]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commitdiff
USB: g_mass_storage: template f_mass_storage.c file created
authorMichal Nazarewicz <m.nazarewicz@samsung.com>
Wed, 28 Oct 2009 15:57:18 +0000 (16:57 +0100)
committerGreg Kroah-Hartman <gregkh@suse.de>
Fri, 11 Dec 2009 19:55:19 +0000 (11:55 -0800)
Copied file_storage.c to f_mass_storage.c which will be used as
template for the Mass Storage composite Function.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/usb/gadget/f_mass_storage.c [new file with mode: 0644]

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
new file mode 100644 (file)
index 0000000..7998402
--- /dev/null
@@ -0,0 +1,3611 @@
+/*
+ * file_storage.c -- File-backed USB Storage Gadget, for USB development
+ *
+ * Copyright (C) 2003-2008 Alan Stern
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions, and the following disclaimer,
+ *    without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The names of the above-listed copyright holders may not be used
+ *    to endorse or promote products derived from this software without
+ *    specific prior written permission.
+ *
+ * ALTERNATIVELY, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") as published by the Free Software
+ * Foundation, either version 2 of that License or (at your option) any
+ * later version.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+ * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+/*
+ * The File-backed Storage Gadget acts as a USB Mass Storage device,
+ * appearing to the host as a disk drive or as a CD-ROM drive.  In addition
+ * to providing an example of a genuinely useful gadget driver for a USB
+ * device, it also illustrates a technique of double-buffering for increased
+ * throughput.  Last but not least, it gives an easy way to probe the
+ * behavior of the Mass Storage drivers in a USB host.
+ *
+ * Backing storage is provided by a regular file or a block device, specified
+ * by the "file" module parameter.  Access can be limited to read-only by
+ * setting the optional "ro" module parameter.  (For CD-ROM emulation,
+ * access is always read-only.)  The gadget will indicate that it has
+ * removable media if the optional "removable" module parameter is set.
+ *
+ * The gadget supports the Control-Bulk (CB), Control-Bulk-Interrupt (CBI),
+ * and Bulk-Only (also known as Bulk-Bulk-Bulk or BBB) transports, selected
+ * by the optional "transport" module parameter.  It also supports the
+ * following protocols: RBC (0x01), ATAPI or SFF-8020i (0x02), QIC-157 (0c03),
+ * UFI (0x04), SFF-8070i (0x05), and transparent SCSI (0x06), selected by
+ * the optional "protocol" module parameter.  In addition, the default
+ * Vendor ID, Product ID, and release number can be overridden.
+ *
+ * There is support for multiple logical units (LUNs), each of which has
+ * its own backing file.  The number of LUNs can be set using the optional
+ * "luns" module parameter (anywhere from 1 to 8), and the corresponding
+ * files are specified using comma-separated lists for "file" and "ro".
+ * The default number of LUNs is taken from the number of "file" elements;
+ * it is 1 if "file" is not given.  If "removable" is not set then a backing
+ * file must be specified for each LUN.  If it is set, then an unspecified
+ * or empty backing filename means the LUN's medium is not loaded.  Ideally
+ * each LUN would be settable independently as a disk drive or a CD-ROM
+ * drive, but currently all LUNs have to be the same type.  The CD-ROM
+ * emulation includes a single data track and no audio tracks; hence there
+ * need be only one backing file per LUN.  Note also that the CD-ROM block
+ * length is set to 512 rather than the more common value 2048.
+ *
+ * Requirements are modest; only a bulk-in and a bulk-out endpoint are
+ * needed (an interrupt-out endpoint is also needed for CBI).  The memory
+ * requirement amounts to two 16K buffers, size configurable by a parameter.
+ * Support is included for both full-speed and high-speed operation.
+ *
+ * Note that the driver is slightly non-portable in that it assumes a
+ * single memory/DMA buffer will be useable for bulk-in, bulk-out, and
+ * interrupt-in endpoints.  With most device controllers this isn't an
+ * issue, but there may be some with hardware restrictions that prevent
+ * a buffer from being used by more than one endpoint.
+ *
+ * Module options:
+ *
+ *     file=filename[,filename...]
+ *                             Required if "removable" is not set, names of
+ *                                     the files or block devices used for
+ *                                     backing storage
+ *     ro=b[,b...]             Default false, booleans for read-only access
+ *     removable               Default false, boolean for removable media
+ *     luns=N                  Default N = number of filenames, number of
+ *                                     LUNs to support
+ *     stall                   Default determined according to the type of
+ *                                     USB device controller (usually true),
+ *                                     boolean to permit the driver to halt
+ *                                     bulk endpoints
+ *     cdrom                   Default false, boolean for whether to emulate
+ *                                     a CD-ROM drive
+ *     transport=XXX           Default BBB, transport name (CB, CBI, or BBB)
+ *     protocol=YYY            Default SCSI, protocol name (RBC, 8020 or
+ *                                     ATAPI, QIC, UFI, 8070, or SCSI;
+ *                                     also 1 - 6)
+ *     vendor=0xVVVV           Default 0x0525 (NetChip), USB Vendor ID
+ *     product=0xPPPP          Default 0xa4a5 (FSG), USB Product ID
+ *     release=0xRRRR          Override the USB release number (bcdDevice)
+ *     buflen=N                Default N=16384, buffer size used (will be
+ *                                     rounded down to a multiple of
+ *                                     PAGE_CACHE_SIZE)
+ *
+ * If CONFIG_USB_FILE_STORAGE_TEST is not set, only the "file", "ro",
+ * "removable", "luns", "stall", and "cdrom" options are available; default
+ * values are used for everything else.
+ *
+ * The pathnames of the backing files and the ro settings are available in
+ * the attribute files "file" and "ro" in the lun<n> subdirectory of the
+ * gadget's sysfs directory.  If the "removable" option is set, writing to
+ * these files will simulate ejecting/loading the medium (writing an empty
+ * line means eject) and adjusting a write-enable tab.  Changes to the ro
+ * setting are not allowed when the medium is loaded or if CD-ROM emulation
+ * is being used.
+ *
+ * This gadget driver is heavily based on "Gadget Zero" by David Brownell.
+ * The driver's SCSI command interface was based on the "Information
+ * technology - Small Computer System Interface - 2" document from
+ * X3T9.2 Project 375D, Revision 10L, 7-SEP-93, available at
+ * <http://www.t10.org/ftp/t10/drafts/s2/s2-r10l.pdf>.  The single exception
+ * is opcode 0x23 (READ FORMAT CAPACITIES), which was based on the
+ * "Universal Serial Bus Mass Storage Class UFI Command Specification"
+ * document, Revision 1.0, December 14, 1998, available at
+ * <http://www.usb.org/developers/devclass_docs/usbmass-ufi10.pdf>.
+ */
+
+
+/*
+ *                             Driver Design
+ *
+ * The FSG driver is fairly straightforward.  There is a main kernel
+ * thread that handles most of the work.  Interrupt routines field
+ * callbacks from the controller driver: bulk- and interrupt-request
+ * completion notifications, endpoint-0 events, and disconnect events.
+ * Completion events are passed to the main thread by wakeup calls.  Many
+ * ep0 requests are handled at interrupt time, but SetInterface,
+ * SetConfiguration, and device reset requests are forwarded to the
+ * thread in the form of "exceptions" using SIGUSR1 signals (since they
+ * should interrupt any ongoing file I/O operations).
+ *
+ * The thread's main routine implements the standard command/data/status
+ * parts of a SCSI interaction.  It and its subroutines are full of tests
+ * for pending signals/exceptions -- all this polling is necessary since
+ * the kernel has no setjmp/longjmp equivalents.  (Maybe this is an
+ * indication that the driver really wants to be running in userspace.)
+ * An important point is that so long as the thread is alive it keeps an
+ * open reference to the backing file.  This will prevent unmounting
+ * the backing file's underlying filesystem and could cause problems
+ * during system shutdown, for example.  To prevent such problems, the
+ * thread catches INT, TERM, and KILL signals and converts them into
+ * an EXIT exception.
+ *
+ * In normal operation the main thread is started during the gadget's
+ * fsg_bind() callback and stopped during fsg_unbind().  But it can also
+ * exit when it receives a signal, and there's no point leaving the
+ * gadget running when the thread is dead.  So just before the thread
+ * exits, it deregisters the gadget driver.  This makes things a little
+ * tricky: The driver is deregistered at two places, and the exiting
+ * thread can indirectly call fsg_unbind() which in turn can tell the
+ * thread to exit.  The first problem is resolved through the use of the
+ * REGISTERED atomic bitflag; the driver will only be deregistered once.
+ * The second problem is resolved by having fsg_unbind() check
+ * fsg->state; it won't try to stop the thread if the state is already
+ * FSG_STATE_TERMINATED.
+ *
+ * To provide maximum throughput, the driver uses a circular pipeline of
+ * buffer heads (struct fsg_buffhd).  In principle the pipeline can be
+ * arbitrarily long; in practice the benefits don't justify having more
+ * than 2 stages (i.e., double buffering).  But it helps to think of the
+ * pipeline as being a long one.  Each buffer head contains a bulk-in and
+ * a bulk-out request pointer (since the buffer can be used for both
+ * output and input -- directions always are given from the host's
+ * point of view) as well as a pointer to the buffer and various state
+ * variables.
+ *
+ * Use of the pipeline follows a simple protocol.  There is a variable
+ * (fsg->next_buffhd_to_fill) that points to the next buffer head to use.
+ * At any time that buffer head may still be in use from an earlier
+ * request, so each buffer head has a state variable indicating whether
+ * it is EMPTY, FULL, or BUSY.  Typical use involves waiting for the
+ * buffer head to be EMPTY, filling the buffer either by file I/O or by
+ * USB I/O (during which the buffer head is BUSY), and marking the buffer
+ * head FULL when the I/O is complete.  Then the buffer will be emptied
+ * (again possibly by USB I/O, during which it is marked BUSY) and
+ * finally marked EMPTY again (possibly by a completion routine).
+ *
+ * A module parameter tells the driver to avoid stalling the bulk
+ * endpoints wherever the transport specification allows.  This is
+ * necessary for some UDCs like the SuperH, which cannot reliably clear a
+ * halt on a bulk endpoint.  However, under certain circumstances the
+ * Bulk-only specification requires a stall.  In such cases the driver
+ * will halt the endpoint and set a flag indicating that it should clear
+ * the halt in software during the next device reset.  Hopefully this
+ * will permit everything to work correctly.  Furthermore, although the
+ * specification allows the bulk-out endpoint to halt when the host sends
+ * too much data, implementing this would cause an unavoidable race.
+ * The driver will always use the "no-stall" approach for OUT transfers.
+ *
+ * One subtle point concerns sending status-stage responses for ep0
+ * requests.  Some of these requests, such as device reset, can involve
+ * interrupting an ongoing file I/O operation, which might take an
+ * arbitrarily long time.  During that delay the host might give up on
+ * the original ep0 request and issue a new one.  When that happens the
+ * driver should not notify the host about completion of the original
+ * request, as the host will no longer be waiting for it.  So the driver
+ * assigns to each ep0 request a unique tag, and it keeps track of the
+ * tag value of the request associated with a long-running exception
+ * (device-reset, interface-change, or configuration-change).  When the
+ * exception handler is finished, the status-stage response is submitted
+ * only if the current ep0 request tag is equal to the exception request
+ * tag.  Thus only the most recently received ep0 request will get a
+ * status-stage response.
+ *
+ * Warning: This driver source file is too long.  It ought to be split up
+ * into a header file plus about 3 separate .c files, to handle the details
+ * of the Gadget, USB Mass Storage, and SCSI protocols.
+ */
+
+
+/* #define VERBOSE_DEBUG */
+/* #define DUMP_MSGS */
+
+
+#include <linux/blkdev.h>
+#include <linux/completion.h>
+#include <linux/dcache.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/fcntl.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/kref.h>
+#include <linux/kthread.h>
+#include <linux/limits.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/string.h>
+#include <linux/freezer.h>
+#include <linux/utsname.h>
+
+#include <linux/usb/ch9.h>
+#include <linux/usb/gadget.h>
+
+#include "gadget_chips.h"
+
+
+
+/*
+ * Kbuild is not very cooperative with respect to linking separately
+ * compiled library objects into one module.  So for now we won't use
+ * separate compilation ... ensuring init/exit sections work to shrink
+ * the runtime footprint, and giving us at least some parts of what
+ * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
+ */
+#include "usbstring.c"
+#include "config.c"
+#include "epautoconf.c"
+
+/*-------------------------------------------------------------------------*/
+
+#define DRIVER_DESC            "File-backed Storage Gadget"
+#define DRIVER_NAME            "g_file_storage"
+#define DRIVER_VERSION         "20 November 2008"
+
+static       char fsg_string_manufacturer[64];
+static const char fsg_string_product[] = DRIVER_DESC;
+static       char fsg_string_serial[13];
+static const char fsg_string_config[] = "Self-powered";
+static const char fsg_string_interface[] = "Mass Storage";
+
+
+#include "storage_common.c"
+
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("Alan Stern");
+MODULE_LICENSE("Dual BSD/GPL");
+
+/*
+ * This driver assumes self-powered hardware and has no way for users to
+ * trigger remote wakeup.  It uses autoconfiguration to select endpoints
+ * and endpoint addresses.
+ */
+
+
+/*-------------------------------------------------------------------------*/
+
+
+/* Encapsulate the module parameter settings */
+
+static struct {
+       char            *file[FSG_MAX_LUNS];
+       int             ro[FSG_MAX_LUNS];
+       unsigned int    num_filenames;
+       unsigned int    num_ros;
+       unsigned int    nluns;
+
+       int             removable;
+       int             can_stall;
+       int             cdrom;
+
+       char            *transport_parm;
+       char            *protocol_parm;
+       unsigned short  vendor;
+       unsigned short  product;
+       unsigned short  release;
+       unsigned int    buflen;
+
+       int             transport_type;
+       char            *transport_name;
+       int             protocol_type;
+       char            *protocol_name;
+
+} mod_data = {                                 // Default values
+       .transport_parm         = "BBB",
+       .protocol_parm          = "SCSI",
+       .removable              = 0,
+       .can_stall              = 1,
+       .cdrom                  = 0,
+       .vendor                 = FSG_VENDOR_ID,
+       .product                = FSG_PRODUCT_ID,
+       .release                = 0xffff,       // Use controller chip type
+       .buflen                 = 16384,
+       };
+
+
+module_param_array_named(file, mod_data.file, charp, &mod_data.num_filenames,
+               S_IRUGO);
+MODULE_PARM_DESC(file, "names of backing files or devices");
+
+module_param_array_named(ro, mod_data.ro, bool, &mod_data.num_ros, S_IRUGO);
+MODULE_PARM_DESC(ro, "true to force read-only");
+
+module_param_named(luns, mod_data.nluns, uint, S_IRUGO);
+MODULE_PARM_DESC(luns, "number of LUNs");
+
+module_param_named(removable, mod_data.removable, bool, S_IRUGO);
+MODULE_PARM_DESC(removable, "true to simulate removable media");
+
+module_param_named(stall, mod_data.can_stall, bool, S_IRUGO);
+MODULE_PARM_DESC(stall, "false to prevent bulk stalls");
+
+module_param_named(cdrom, mod_data.cdrom, bool, S_IRUGO);
+MODULE_PARM_DESC(cdrom, "true to emulate cdrom instead of disk");
+
+
+/* In the non-TEST version, only the module parameters listed above
+ * are available. */
+#ifdef CONFIG_USB_FILE_STORAGE_TEST
+
+module_param_named(transport, mod_data.transport_parm, charp, S_IRUGO);
+MODULE_PARM_DESC(transport, "type of transport (BBB, CBI, or CB)");
+
+module_param_named(protocol, mod_data.protocol_parm, charp, S_IRUGO);
+MODULE_PARM_DESC(protocol, "type of protocol (RBC, 8020, QIC, UFI, "
+               "8070, or SCSI)");
+
+module_param_named(vendor, mod_data.vendor, ushort, S_IRUGO);
+MODULE_PARM_DESC(vendor, "USB Vendor ID");
+
+module_param_named(product, mod_data.product, ushort, S_IRUGO);
+MODULE_PARM_DESC(product, "USB Product ID");
+
+module_param_named(release, mod_data.release, ushort, S_IRUGO);
+MODULE_PARM_DESC(release, "USB release number");
+
+module_param_named(buflen, mod_data.buflen, uint, S_IRUGO);
+MODULE_PARM_DESC(buflen, "I/O buffer size");
+
+#endif /* CONFIG_USB_FILE_STORAGE_TEST */
+
+
+/*
+ * These definitions will permit the compiler to avoid generating code for
+ * parts of the driver that aren't used in the non-TEST version.  Even gcc
+ * can recognize when a test of a constant expression yields a dead code
+ * path.
+ */
+
+#ifdef CONFIG_USB_FILE_STORAGE_TEST
+
+#define transport_is_bbb()     (mod_data.transport_type == USB_PR_BULK)
+#define transport_is_cbi()     (mod_data.transport_type == USB_PR_CBI)
+#define protocol_is_scsi()     (mod_data.protocol_type == USB_SC_SCSI)
+
+#else
+
+#define transport_is_bbb()     1
+#define transport_is_cbi()     0
+#define protocol_is_scsi()     1
+
+#endif /* CONFIG_USB_FILE_STORAGE_TEST */
+
+
+/*-------------------------------------------------------------------------*/
+
+
+struct fsg_dev {
+       /* lock protects: state, all the req_busy's, and cbbuf_cmnd */
+       spinlock_t              lock;
+       struct usb_gadget       *gadget;
+
+       /* filesem protects: backing files in use */
+       struct rw_semaphore     filesem;
+
+       /* reference counting: wait until all LUNs are released */
+       struct kref             ref;
+
+       struct usb_ep           *ep0;           // Handy copy of gadget->ep0
+       struct usb_request      *ep0req;        // For control responses
+       unsigned int            ep0_req_tag;
+       const char              *ep0req_name;
+
+       struct usb_request      *intreq;        // For interrupt responses
+       int                     intreq_busy;
+       struct fsg_buffhd       *intr_buffhd;
+
+       unsigned int            bulk_out_maxpacket;
+       enum fsg_state          state;          // For exception handling
+       unsigned int            exception_req_tag;
+
+       u8                      config, new_config;
+
+       unsigned int            running : 1;
+       unsigned int            bulk_in_enabled : 1;
+       unsigned int            bulk_out_enabled : 1;
+       unsigned int            intr_in_enabled : 1;
+       unsigned int            phase_error : 1;
+       unsigned int            short_packet_received : 1;
+       unsigned int            bad_lun_okay : 1;
+
+       unsigned long           atomic_bitflags;
+#define REGISTERED             0
+#define IGNORE_BULK_OUT                1
+#define SUSPENDED              2
+
+       struct usb_ep           *bulk_in;
+       struct usb_ep           *bulk_out;
+       struct usb_ep           *intr_in;
+
+       struct fsg_buffhd       *next_buffhd_to_fill;
+       struct fsg_buffhd       *next_buffhd_to_drain;
+       struct fsg_buffhd       buffhds[FSG_NUM_BUFFERS];
+
+       int                     thread_wakeup_needed;
+       struct completion       thread_notifier;
+       struct task_struct      *thread_task;
+
+       int                     cmnd_size;
+       u8                      cmnd[MAX_COMMAND_SIZE];
+       enum data_direction     data_dir;
+       u32                     data_size;
+       u32                     data_size_from_cmnd;
+       u32                     tag;
+       unsigned int            lun;
+       u32                     residue;
+       u32                     usb_amount_left;
+
+       /* The CB protocol offers no way for a host to know when a command
+        * has completed.  As a result the next command may arrive early,
+        * and we will still have to handle it.  For that reason we need
+        * a buffer to store new commands when using CB (or CBI, which
+        * does not oblige a host to wait for command completion either). */
+       int                     cbbuf_cmnd_size;
+       u8                      cbbuf_cmnd[MAX_COMMAND_SIZE];
+
+       unsigned int            nluns;
+       struct fsg_lun          *luns;
+       struct fsg_lun          *curlun;
+};
+
+typedef void (*fsg_routine_t)(struct fsg_dev *);
+
+static int exception_in_progress(struct fsg_dev *fsg)
+{
+       return (fsg->state > FSG_STATE_IDLE);
+}
+
+/* Make bulk-out requests be divisible by the maxpacket size */
+static void set_bulk_out_req_length(struct fsg_dev *fsg,
+               struct fsg_buffhd *bh, unsigned int length)
+{
+       unsigned int    rem;
+
+       bh->bulk_out_intended_length = length;
+       rem = length % fsg->bulk_out_maxpacket;
+       if (rem > 0)
+               length += fsg->bulk_out_maxpacket - rem;
+       bh->outreq->length = length;
+}
+
+static struct fsg_dev                  *the_fsg;
+static struct usb_gadget_driver                fsg_driver;
+
+
+/*-------------------------------------------------------------------------*/
+
+static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
+{
+       const char      *name;
+
+       if (ep == fsg->bulk_in)
+               name = "bulk-in";
+       else if (ep == fsg->bulk_out)
+               name = "bulk-out";
+       else
+               name = ep->name;
+       DBG(fsg, "%s set halt\n", name);
+       return usb_ep_set_halt(ep);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * DESCRIPTORS ... most are static, but strings and (full) configuration
+ * descriptors are built on demand.  Also the (static) config and interface
+ * descriptors are adjusted during fsg_bind().
+ */
+
+/* There is only one configuration. */
+#define        CONFIG_VALUE            1
+
+static struct usb_device_descriptor
+device_desc = {
+       .bLength =              sizeof device_desc,
+       .bDescriptorType =      USB_DT_DEVICE,
+
+       .bcdUSB =               cpu_to_le16(0x0200),
+       .bDeviceClass =         USB_CLASS_PER_INTERFACE,
+
+       /* The next three values can be overridden by module parameters */
+       .idVendor =             cpu_to_le16(FSG_VENDOR_ID),
+       .idProduct =            cpu_to_le16(FSG_PRODUCT_ID),
+       .bcdDevice =            cpu_to_le16(0xffff),
+
+       .iManufacturer =        FSG_STRING_MANUFACTURER,
+       .iProduct =             FSG_STRING_PRODUCT,
+       .iSerialNumber =        FSG_STRING_SERIAL,
+       .bNumConfigurations =   1,
+};
+
+static struct usb_config_descriptor
+config_desc = {
+       .bLength =              sizeof config_desc,
+       .bDescriptorType =      USB_DT_CONFIG,
+
+       /* wTotalLength computed by usb_gadget_config_buf() */
+       .bNumInterfaces =       1,
+       .bConfigurationValue =  CONFIG_VALUE,
+       .iConfiguration =       FSG_STRING_CONFIG,
+       .bmAttributes =         USB_CONFIG_ATT_ONE | USB_CONFIG_ATT_SELFPOWER,
+       .bMaxPower =            CONFIG_USB_GADGET_VBUS_DRAW / 2,
+};
+
+
+static struct usb_qualifier_descriptor
+dev_qualifier = {
+       .bLength =              sizeof dev_qualifier,
+       .bDescriptorType =      USB_DT_DEVICE_QUALIFIER,
+
+       .bcdUSB =               cpu_to_le16(0x0200),
+       .bDeviceClass =         USB_CLASS_PER_INTERFACE,
+
+       .bNumConfigurations =   1,
+};
+
+
+
+/*
+ * Config descriptors must agree with the code that sets configurations
+ * and with code managing interfaces and their altsettings.  They must
+ * also handle different speeds and other-speed requests.
+ */
+static int populate_config_buf(struct usb_gadget *gadget,
+               u8 *buf, u8 type, unsigned index)
+{
+       enum usb_device_speed                   speed = gadget->speed;
+       int                                     len;
+       const struct usb_descriptor_header      **function;
+
+       if (index > 0)
+               return -EINVAL;
+
+       if (gadget_is_dualspeed(gadget) && type == USB_DT_OTHER_SPEED_CONFIG)
+               speed = (USB_SPEED_FULL + USB_SPEED_HIGH) - speed;
+       if (gadget_is_dualspeed(gadget) && speed == USB_SPEED_HIGH)
+               function = fsg_hs_function;
+       else
+               function = fsg_fs_function;
+
+       /* for now, don't advertise srp-only devices */
+       if (!gadget_is_otg(gadget))
+               function++;
+
+       len = usb_gadget_config_buf(&config_desc, buf, EP0_BUFSIZE, function);
+       ((struct usb_config_descriptor *) buf)->bDescriptorType = type;
+       return len;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* These routines may be called in process context or in_irq */
+
+/* Caller must hold fsg->lock */
+static void wakeup_thread(struct fsg_dev *fsg)
+{
+       /* Tell the main thread that something has happened */
+       fsg->thread_wakeup_needed = 1;
+       if (fsg->thread_task)
+               wake_up_process(fsg->thread_task);
+}
+
+
+static void raise_exception(struct fsg_dev *fsg, enum fsg_state new_state)
+{
+       unsigned long           flags;
+
+       /* Do nothing if a higher-priority exception is already in progress.
+        * If a lower-or-equal priority exception is in progress, preempt it
+        * and notify the main thread by sending it a signal. */
+       spin_lock_irqsave(&fsg->lock, flags);
+       if (fsg->state <= new_state) {
+               fsg->exception_req_tag = fsg->ep0_req_tag;
+               fsg->state = new_state;
+               if (fsg->thread_task)
+                       send_sig_info(SIGUSR1, SEND_SIG_FORCED,
+                                       fsg->thread_task);
+       }
+       spin_unlock_irqrestore(&fsg->lock, flags);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* The disconnect callback and ep0 routines.  These always run in_irq,
+ * except that ep0_queue() is called in the main thread to acknowledge
+ * completion of various requests: set config, set interface, and
+ * Bulk-only device reset. */
+
+static void fsg_disconnect(struct usb_gadget *gadget)
+{
+       struct fsg_dev          *fsg = get_gadget_data(gadget);
+
+       DBG(fsg, "disconnect or port reset\n");
+       raise_exception(fsg, FSG_STATE_DISCONNECT);
+}
+
+
+static int ep0_queue(struct fsg_dev *fsg)
+{
+       int     rc;
+
+       rc = usb_ep_queue(fsg->ep0, fsg->ep0req, GFP_ATOMIC);
+       if (rc != 0 && rc != -ESHUTDOWN) {
+
+               /* We can't do much more than wait for a reset */
+               WARNING(fsg, "error in submission: %s --> %d\n",
+                               fsg->ep0->name, rc);
+       }
+       return rc;
+}
+
+static void ep0_complete(struct usb_ep *ep, struct usb_request *req)
+{
+       struct fsg_dev          *fsg = ep->driver_data;
+
+       if (req->actual > 0)
+               dump_msg(fsg, fsg->ep0req_name, req->buf, req->actual);
+       if (req->status || req->actual != req->length)
+               DBG(fsg, "%s --> %d, %u/%u\n", __func__,
+                               req->status, req->actual, req->length);
+       if (req->status == -ECONNRESET)         // Request was cancelled
+               usb_ep_fifo_flush(ep);
+
+       if (req->status == 0 && req->context)
+               ((fsg_routine_t) (req->context))(fsg);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Bulk and interrupt endpoint completion handlers.
+ * These always run in_irq. */
+
+static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
+{
+       struct fsg_dev          *fsg = ep->driver_data;
+       struct fsg_buffhd       *bh = req->context;
+
+       if (req->status || req->actual != req->length)
+               DBG(fsg, "%s --> %d, %u/%u\n", __func__,
+                               req->status, req->actual, req->length);
+       if (req->status == -ECONNRESET)         // Request was cancelled
+               usb_ep_fifo_flush(ep);
+
+       /* Hold the lock while we update the request and buffer states */
+       smp_wmb();
+       spin_lock(&fsg->lock);
+       bh->inreq_busy = 0;
+       bh->state = BUF_STATE_EMPTY;
+       wakeup_thread(fsg);
+       spin_unlock(&fsg->lock);
+}
+
+static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
+{
+       struct fsg_dev          *fsg = ep->driver_data;
+       struct fsg_buffhd       *bh = req->context;
+
+       dump_msg(fsg, "bulk-out", req->buf, req->actual);
+       if (req->status || req->actual != bh->bulk_out_intended_length)
+               DBG(fsg, "%s --> %d, %u/%u\n", __func__,
+                               req->status, req->actual,
+                               bh->bulk_out_intended_length);
+       if (req->status == -ECONNRESET)         // Request was cancelled
+               usb_ep_fifo_flush(ep);
+
+       /* Hold the lock while we update the request and buffer states */
+       smp_wmb();
+       spin_lock(&fsg->lock);
+       bh->outreq_busy = 0;
+       bh->state = BUF_STATE_FULL;
+       wakeup_thread(fsg);
+       spin_unlock(&fsg->lock);
+}
+
+
+#ifdef CONFIG_USB_FILE_STORAGE_TEST
+static void intr_in_complete(struct usb_ep *ep, struct usb_request *req)
+{
+       struct fsg_dev          *fsg = ep->driver_data;
+       struct fsg_buffhd       *bh = req->context;
+
+       if (req->status || req->actual != req->length)
+               DBG(fsg, "%s --> %d, %u/%u\n", __func__,
+                               req->status, req->actual, req->length);
+       if (req->status == -ECONNRESET)         // Request was cancelled
+               usb_ep_fifo_flush(ep);
+
+       /* Hold the lock while we update the request and buffer states */
+       smp_wmb();
+       spin_lock(&fsg->lock);
+       fsg->intreq_busy = 0;
+       bh->state = BUF_STATE_EMPTY;
+       wakeup_thread(fsg);
+       spin_unlock(&fsg->lock);
+}
+
+#else
+static void intr_in_complete(struct usb_ep *ep, struct usb_request *req)
+{}
+#endif /* CONFIG_USB_FILE_STORAGE_TEST */
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Ep0 class-specific handlers.  These always run in_irq. */
+
+#ifdef CONFIG_USB_FILE_STORAGE_TEST
+static void received_cbi_adsc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       struct usb_request      *req = fsg->ep0req;
+       static u8               cbi_reset_cmnd[6] = {
+                       SC_SEND_DIAGNOSTIC, 4, 0xff, 0xff, 0xff, 0xff};
+
+       /* Error in command transfer? */
+       if (req->status || req->length != req->actual ||
+                       req->actual < 6 || req->actual > MAX_COMMAND_SIZE) {
+
+               /* Not all controllers allow a protocol stall after
+                * receiving control-out data, but we'll try anyway. */
+               fsg_set_halt(fsg, fsg->ep0);
+               return;                 // Wait for reset
+       }
+
+       /* Is it the special reset command? */
+       if (req->actual >= sizeof cbi_reset_cmnd &&
+                       memcmp(req->buf, cbi_reset_cmnd,
+                               sizeof cbi_reset_cmnd) == 0) {
+
+               /* Raise an exception to stop the current operation
+                * and reinitialize our state. */
+               DBG(fsg, "cbi reset request\n");
+               raise_exception(fsg, FSG_STATE_RESET);
+               return;
+       }
+
+       VDBG(fsg, "CB[I] accept device-specific command\n");
+       spin_lock(&fsg->lock);
+
+       /* Save the command for later */
+       if (fsg->cbbuf_cmnd_size)
+               WARNING(fsg, "CB[I] overwriting previous command\n");
+       fsg->cbbuf_cmnd_size = req->actual;
+       memcpy(fsg->cbbuf_cmnd, req->buf, fsg->cbbuf_cmnd_size);
+
+       wakeup_thread(fsg);
+       spin_unlock(&fsg->lock);
+}
+
+#else
+static void received_cbi_adsc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{}
+#endif /* CONFIG_USB_FILE_STORAGE_TEST */
+
+
+static int class_setup_req(struct fsg_dev *fsg,
+               const struct usb_ctrlrequest *ctrl)
+{
+       struct usb_request      *req = fsg->ep0req;
+       int                     value = -EOPNOTSUPP;
+       u16                     w_index = le16_to_cpu(ctrl->wIndex);
+       u16                     w_value = le16_to_cpu(ctrl->wValue);
+       u16                     w_length = le16_to_cpu(ctrl->wLength);
+
+       if (!fsg->config)
+               return value;
+
+       /* Handle Bulk-only class-specific requests */
+       if (transport_is_bbb()) {
+               switch (ctrl->bRequest) {
+
+               case USB_BULK_RESET_REQUEST:
+                       if (ctrl->bRequestType != (USB_DIR_OUT |
+                                       USB_TYPE_CLASS | USB_RECIP_INTERFACE))
+                               break;
+                       if (w_index != 0 || w_value != 0) {
+                               value = -EDOM;
+                               break;
+                       }
+
+                       /* Raise an exception to stop the current operation
+                        * and reinitialize our state. */
+                       DBG(fsg, "bulk reset request\n");
+                       raise_exception(fsg, FSG_STATE_RESET);
+                       value = DELAYED_STATUS;
+                       break;
+
+               case USB_BULK_GET_MAX_LUN_REQUEST:
+                       if (ctrl->bRequestType != (USB_DIR_IN |
+                                       USB_TYPE_CLASS | USB_RECIP_INTERFACE))
+                               break;
+                       if (w_index != 0 || w_value != 0) {
+                               value = -EDOM;
+                               break;
+                       }
+                       VDBG(fsg, "get max LUN\n");
+                       *(u8 *) req->buf = fsg->nluns - 1;
+                       value = 1;
+                       break;
+               }
+       }
+
+       /* Handle CBI class-specific requests */
+       else {
+               switch (ctrl->bRequest) {
+
+               case USB_CBI_ADSC_REQUEST:
+                       if (ctrl->bRequestType != (USB_DIR_OUT |
+                                       USB_TYPE_CLASS | USB_RECIP_INTERFACE))
+                               break;
+                       if (w_index != 0 || w_value != 0) {
+                               value = -EDOM;
+                               break;
+                       }
+                       if (w_length > MAX_COMMAND_SIZE) {
+                               value = -EOVERFLOW;
+                               break;
+                       }
+                       value = w_length;
+                       fsg->ep0req->context = received_cbi_adsc;
+                       break;
+               }
+       }
+
+       if (value == -EOPNOTSUPP)
+               VDBG(fsg,
+                       "unknown class-specific control req "
+                       "%02x.%02x v%04x i%04x l%u\n",
+                       ctrl->bRequestType, ctrl->bRequest,
+                       le16_to_cpu(ctrl->wValue), w_index, w_length);
+       return value;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Ep0 standard request handlers.  These always run in_irq. */
+
+static int standard_setup_req(struct fsg_dev *fsg,
+               const struct usb_ctrlrequest *ctrl)
+{
+       struct usb_request      *req = fsg->ep0req;
+       int                     value = -EOPNOTSUPP;
+       u16                     w_index = le16_to_cpu(ctrl->wIndex);
+       u16                     w_value = le16_to_cpu(ctrl->wValue);
+
+       /* Usually this just stores reply data in the pre-allocated ep0 buffer,
+        * but config change events will also reconfigure hardware. */
+       switch (ctrl->bRequest) {
+
+       case USB_REQ_GET_DESCRIPTOR:
+               if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
+                               USB_RECIP_DEVICE))
+                       break;
+               switch (w_value >> 8) {
+
+               case USB_DT_DEVICE:
+                       VDBG(fsg, "get device descriptor\n");
+                       value = sizeof device_desc;
+                       memcpy(req->buf, &device_desc, value);
+                       break;
+               case USB_DT_DEVICE_QUALIFIER:
+                       VDBG(fsg, "get device qualifier\n");
+                       if (!gadget_is_dualspeed(fsg->gadget))
+                               break;
+                       value = sizeof dev_qualifier;
+                       memcpy(req->buf, &dev_qualifier, value);
+                       break;
+
+               case USB_DT_OTHER_SPEED_CONFIG:
+                       VDBG(fsg, "get other-speed config descriptor\n");
+                       if (!gadget_is_dualspeed(fsg->gadget))
+                               break;
+                       goto get_config;
+               case USB_DT_CONFIG:
+                       VDBG(fsg, "get configuration descriptor\n");
+get_config:
+                       value = populate_config_buf(fsg->gadget,
+                                       req->buf,
+                                       w_value >> 8,
+                                       w_value & 0xff);
+                       break;
+
+               case USB_DT_STRING:
+                       VDBG(fsg, "get string descriptor\n");
+
+                       /* wIndex == language code */
+                       value = usb_gadget_get_string(&fsg_stringtab,
+                                       w_value & 0xff, req->buf);
+                       break;
+               }
+               break;
+
+       /* One config, two speeds */
+       case USB_REQ_SET_CONFIGURATION:
+               if (ctrl->bRequestType != (USB_DIR_OUT | USB_TYPE_STANDARD |
+                               USB_RECIP_DEVICE))
+                       break;
+               VDBG(fsg, "set configuration\n");
+               if (w_value == CONFIG_VALUE || w_value == 0) {
+                       fsg->new_config = w_value;
+
+                       /* Raise an exception to wipe out previous transaction
+                        * state (queued bufs, etc) and set the new config. */
+                       raise_exception(fsg, FSG_STATE_CONFIG_CHANGE);
+                       value = DELAYED_STATUS;
+               }
+               break;
+       case USB_REQ_GET_CONFIGURATION:
+               if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
+                               USB_RECIP_DEVICE))
+                       break;
+               VDBG(fsg, "get configuration\n");
+               *(u8 *) req->buf = fsg->config;
+               value = 1;
+               break;
+
+       case USB_REQ_SET_INTERFACE:
+               if (ctrl->bRequestType != (USB_DIR_OUT| USB_TYPE_STANDARD |
+                               USB_RECIP_INTERFACE))
+                       break;
+               if (fsg->config && w_index == 0) {
+
+                       /* Raise an exception to wipe out previous transaction
+                        * state (queued bufs, etc) and install the new
+                        * interface altsetting. */
+                       raise_exception(fsg, FSG_STATE_INTERFACE_CHANGE);
+                       value = DELAYED_STATUS;
+               }
+               break;
+       case USB_REQ_GET_INTERFACE:
+               if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_STANDARD |
+                               USB_RECIP_INTERFACE))
+                       break;
+               if (!fsg->config)
+                       break;
+               if (w_index != 0) {
+                       value = -EDOM;
+                       break;
+               }
+               VDBG(fsg, "get interface\n");
+               *(u8 *) req->buf = 0;
+               value = 1;
+               break;
+
+       default:
+               VDBG(fsg,
+                       "unknown control req %02x.%02x v%04x i%04x l%u\n",
+                       ctrl->bRequestType, ctrl->bRequest,
+                       w_value, w_index, le16_to_cpu(ctrl->wLength));
+       }
+
+       return value;
+}
+
+
+static int fsg_setup(struct usb_gadget *gadget,
+               const struct usb_ctrlrequest *ctrl)
+{
+       struct fsg_dev          *fsg = get_gadget_data(gadget);
+       int                     rc;
+       int                     w_length = le16_to_cpu(ctrl->wLength);
+
+       ++fsg->ep0_req_tag;             // Record arrival of a new request
+       fsg->ep0req->context = NULL;
+       fsg->ep0req->length = 0;
+       dump_msg(fsg, "ep0-setup", (u8 *) ctrl, sizeof(*ctrl));
+
+       if ((ctrl->bRequestType & USB_TYPE_MASK) == USB_TYPE_CLASS)
+               rc = class_setup_req(fsg, ctrl);
+       else
+               rc = standard_setup_req(fsg, ctrl);
+
+       /* Respond with data/status or defer until later? */
+       if (rc >= 0 && rc != DELAYED_STATUS) {
+               rc = min(rc, w_length);
+               fsg->ep0req->length = rc;
+               fsg->ep0req->zero = rc < w_length;
+               fsg->ep0req_name = (ctrl->bRequestType & USB_DIR_IN ?
+                               "ep0-in" : "ep0-out");
+               rc = ep0_queue(fsg);
+       }
+
+       /* Device either stalls (rc < 0) or reports success */
+       return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* All the following routines run in process context */
+
+
+/* Use this for bulk or interrupt transfers, not ep0 */
+static void start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
+               struct usb_request *req, int *pbusy,
+               enum fsg_buffer_state *state)
+{
+       int     rc;
+
+       if (ep == fsg->bulk_in)
+               dump_msg(fsg, "bulk-in", req->buf, req->length);
+       else if (ep == fsg->intr_in)
+               dump_msg(fsg, "intr-in", req->buf, req->length);
+
+       spin_lock_irq(&fsg->lock);
+       *pbusy = 1;
+       *state = BUF_STATE_BUSY;
+       spin_unlock_irq(&fsg->lock);
+       rc = usb_ep_queue(ep, req, GFP_KERNEL);
+       if (rc != 0) {
+               *pbusy = 0;
+               *state = BUF_STATE_EMPTY;
+
+               /* We can't do much more than wait for a reset */
+
+               /* Note: currently the net2280 driver fails zero-length
+                * submissions if DMA is enabled. */
+               if (rc != -ESHUTDOWN && !(rc == -EOPNOTSUPP &&
+                                               req->length == 0))
+                       WARNING(fsg, "error in submission: %s --> %d\n",
+                                       ep->name, rc);
+       }
+}
+
+
+static int sleep_thread(struct fsg_dev *fsg)
+{
+       int     rc = 0;
+
+       /* Wait until a signal arrives or we are woken up */
+       for (;;) {
+               try_to_freeze();
+               set_current_state(TASK_INTERRUPTIBLE);
+               if (signal_pending(current)) {
+                       rc = -EINTR;
+                       break;
+               }
+               if (fsg->thread_wakeup_needed)
+                       break;
+               schedule();
+       }
+       __set_current_state(TASK_RUNNING);
+       fsg->thread_wakeup_needed = 0;
+       return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int do_read(struct fsg_dev *fsg)
+{
+       struct fsg_lun          *curlun = fsg->curlun;
+       u32                     lba;
+       struct fsg_buffhd       *bh;
+       int                     rc;
+       u32                     amount_left;
+       loff_t                  file_offset, file_offset_tmp;
+       unsigned int            amount;
+       unsigned int            partial_page;
+       ssize_t                 nread;
+
+       /* Get the starting Logical Block Address and check that it's
+        * not too big */
+       if (fsg->cmnd[0] == SC_READ_6)
+               lba = get_unaligned_be24(&fsg->cmnd[1]);
+       else {
+               lba = get_unaligned_be32(&fsg->cmnd[2]);
+
+               /* We allow DPO (Disable Page Out = don't save data in the
+                * cache) and FUA (Force Unit Access = don't read from the
+                * cache), but we don't implement them. */
+               if ((fsg->cmnd[1] & ~0x18) != 0) {
+                       curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+                       return -EINVAL;
+               }
+       }
+       if (lba >= curlun->num_sectors) {
+               curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+               return -EINVAL;
+       }
+       file_offset = ((loff_t) lba) << 9;
+
+       /* Carry out the file reads */
+       amount_left = fsg->data_size_from_cmnd;
+       if (unlikely(amount_left == 0))
+               return -EIO;            // No default reply
+
+       for (;;) {
+
+               /* Figure out how much we need to read:
+                * Try to read the remaining amount.
+                * But don't read more than the buffer size.
+                * And don't try to read past the end of the file.
+                * Finally, if we're not at a page boundary, don't read past
+                *      the next page.
+                * If this means reading 0 then we were asked to read past
+                *      the end of file. */
+               amount = min((unsigned int) amount_left, mod_data.buflen);
+               amount = min((loff_t) amount,
+                               curlun->file_length - file_offset);
+               partial_page = file_offset & (PAGE_CACHE_SIZE - 1);
+               if (partial_page > 0)
+                       amount = min(amount, (unsigned int) PAGE_CACHE_SIZE -
+                                       partial_page);
+
+               /* Wait for the next buffer to become available */
+               bh = fsg->next_buffhd_to_fill;
+               while (bh->state != BUF_STATE_EMPTY) {
+                       rc = sleep_thread(fsg);
+                       if (rc)
+                               return rc;
+               }
+
+               /* If we were asked to read past the end of file,
+                * end with an empty buffer. */
+               if (amount == 0) {
+                       curlun->sense_data =
+                                       SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+                       curlun->sense_data_info = file_offset >> 9;
+                       curlun->info_valid = 1;
+                       bh->inreq->length = 0;
+                       bh->state = BUF_STATE_FULL;
+                       break;
+               }
+
+               /* Perform the read */
+               file_offset_tmp = file_offset;
+               nread = vfs_read(curlun->filp,
+                               (char __user *) bh->buf,
+                               amount, &file_offset_tmp);
+               VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
+                               (unsigned long long) file_offset,
+                               (int) nread);
+               if (signal_pending(current))
+                       return -EINTR;
+
+               if (nread < 0) {
+                       LDBG(curlun, "error in file read: %d\n",
+                                       (int) nread);
+                       nread = 0;
+               } else if (nread < amount) {
+                       LDBG(curlun, "partial file read: %d/%u\n",
+                                       (int) nread, amount);
+                       nread -= (nread & 511); // Round down to a block
+               }
+               file_offset  += nread;
+               amount_left  -= nread;
+               fsg->residue -= nread;
+               bh->inreq->length = nread;
+               bh->state = BUF_STATE_FULL;
+
+               /* If an error occurred, report it and its position */
+               if (nread < amount) {
+                       curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
+                       curlun->sense_data_info = file_offset >> 9;
+                       curlun->info_valid = 1;
+                       break;
+               }
+
+               if (amount_left == 0)
+                       break;          // No more left to read
+
+               /* Send this buffer and go read some more */
+               bh->inreq->zero = 0;
+               start_transfer(fsg, fsg->bulk_in, bh->inreq,
+                               &bh->inreq_busy, &bh->state);
+               fsg->next_buffhd_to_fill = bh->next;
+       }
+
+       return -EIO;            // No default reply
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int do_write(struct fsg_dev *fsg)
+{
+       struct fsg_lun          *curlun = fsg->curlun;
+       u32                     lba;
+       struct fsg_buffhd       *bh;
+       int                     get_some_more;
+       u32                     amount_left_to_req, amount_left_to_write;
+       loff_t                  usb_offset, file_offset, file_offset_tmp;
+       unsigned int            amount;
+       unsigned int            partial_page;
+       ssize_t                 nwritten;
+       int                     rc;
+
+       if (curlun->ro) {
+               curlun->sense_data = SS_WRITE_PROTECTED;
+               return -EINVAL;
+       }
+       spin_lock(&curlun->filp->f_lock);
+       curlun->filp->f_flags &= ~O_SYNC;       // Default is not to wait
+       spin_unlock(&curlun->filp->f_lock);
+
+       /* Get the starting Logical Block Address and check that it's
+        * not too big */
+       if (fsg->cmnd[0] == SC_WRITE_6)
+               lba = get_unaligned_be24(&fsg->cmnd[1]);
+       else {
+               lba = get_unaligned_be32(&fsg->cmnd[2]);
+
+               /* We allow DPO (Disable Page Out = don't save data in the
+                * cache) and FUA (Force Unit Access = write directly to the
+                * medium).  We don't implement DPO; we implement FUA by
+                * performing synchronous output. */
+               if ((fsg->cmnd[1] & ~0x18) != 0) {
+                       curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+                       return -EINVAL;
+               }
+               if (fsg->cmnd[1] & 0x08) {      // FUA
+                       spin_lock(&curlun->filp->f_lock);
+                       curlun->filp->f_flags |= O_SYNC;
+                       spin_unlock(&curlun->filp->f_lock);
+               }
+       }
+       if (lba >= curlun->num_sectors) {
+               curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+               return -EINVAL;
+       }
+
+       /* Carry out the file writes */
+       get_some_more = 1;
+       file_offset = usb_offset = ((loff_t) lba) << 9;
+       amount_left_to_req = amount_left_to_write = fsg->data_size_from_cmnd;
+
+       while (amount_left_to_write > 0) {
+
+               /* Queue a request for more data from the host */
+               bh = fsg->next_buffhd_to_fill;
+               if (bh->state == BUF_STATE_EMPTY && get_some_more) {
+
+                       /* Figure out how much we want to get:
+                        * Try to get the remaining amount.
+                        * But don't get more than the buffer size.
+                        * And don't try to go past the end of the file.
+                        * If we're not at a page boundary,
+                        *      don't go past the next page.
+                        * If this means getting 0, then we were asked
+                        *      to write past the end of file.
+                        * Finally, round down to a block boundary. */
+                       amount = min(amount_left_to_req, mod_data.buflen);
+                       amount = min((loff_t) amount, curlun->file_length -
+                                       usb_offset);
+                       partial_page = usb_offset & (PAGE_CACHE_SIZE - 1);
+                       if (partial_page > 0)
+                               amount = min(amount,
+       (unsigned int) PAGE_CACHE_SIZE - partial_page);
+
+                       if (amount == 0) {
+                               get_some_more = 0;
+                               curlun->sense_data =
+                                       SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+                               curlun->sense_data_info = usb_offset >> 9;
+                               curlun->info_valid = 1;
+                               continue;
+                       }
+                       amount -= (amount & 511);
+                       if (amount == 0) {
+
+                               /* Why were we were asked to transfer a
+                                * partial block? */
+                               get_some_more = 0;
+                               continue;
+                       }
+
+                       /* Get the next buffer */
+                       usb_offset += amount;
+                       fsg->usb_amount_left -= amount;
+                       amount_left_to_req -= amount;
+                       if (amount_left_to_req == 0)
+                               get_some_more = 0;
+
+                       /* amount is always divisible by 512, hence by
+                        * the bulk-out maxpacket size */
+                       bh->outreq->length = bh->bulk_out_intended_length =
+                                       amount;
+                       bh->outreq->short_not_ok = 1;
+                       start_transfer(fsg, fsg->bulk_out, bh->outreq,
+                                       &bh->outreq_busy, &bh->state);
+                       fsg->next_buffhd_to_fill = bh->next;
+                       continue;
+               }
+
+               /* Write the received data to the backing file */
+               bh = fsg->next_buffhd_to_drain;
+               if (bh->state == BUF_STATE_EMPTY && !get_some_more)
+                       break;                  // We stopped early
+               if (bh->state == BUF_STATE_FULL) {
+                       smp_rmb();
+                       fsg->next_buffhd_to_drain = bh->next;
+                       bh->state = BUF_STATE_EMPTY;
+
+                       /* Did something go wrong with the transfer? */
+                       if (bh->outreq->status != 0) {
+                               curlun->sense_data = SS_COMMUNICATION_FAILURE;
+                               curlun->sense_data_info = file_offset >> 9;
+                               curlun->info_valid = 1;
+                               break;
+                       }
+
+                       amount = bh->outreq->actual;
+                       if (curlun->file_length - file_offset < amount) {
+                               LERROR(curlun,
+       "write %u @ %llu beyond end %llu\n",
+       amount, (unsigned long long) file_offset,
+       (unsigned long long) curlun->file_length);
+                               amount = curlun->file_length - file_offset;
+                       }
+
+                       /* Perform the write */
+                       file_offset_tmp = file_offset;
+                       nwritten = vfs_write(curlun->filp,
+                                       (char __user *) bh->buf,
+                                       amount, &file_offset_tmp);
+                       VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
+                                       (unsigned long long) file_offset,
+                                       (int) nwritten);
+                       if (signal_pending(current))
+                               return -EINTR;          // Interrupted!
+
+                       if (nwritten < 0) {
+                               LDBG(curlun, "error in file write: %d\n",
+                                               (int) nwritten);
+                               nwritten = 0;
+                       } else if (nwritten < amount) {
+                               LDBG(curlun, "partial file write: %d/%u\n",
+                                               (int) nwritten, amount);
+                               nwritten -= (nwritten & 511);
+                                               // Round down to a block
+                       }
+                       file_offset += nwritten;
+                       amount_left_to_write -= nwritten;
+                       fsg->residue -= nwritten;
+
+                       /* If an error occurred, report it and its position */
+                       if (nwritten < amount) {
+                               curlun->sense_data = SS_WRITE_ERROR;
+                               curlun->sense_data_info = file_offset >> 9;
+                               curlun->info_valid = 1;
+                               break;
+                       }
+
+                       /* Did the host decide to stop early? */
+                       if (bh->outreq->actual != bh->outreq->length) {
+                               fsg->short_packet_received = 1;
+                               break;
+                       }
+                       continue;
+               }
+
+               /* Wait for something to happen */
+               rc = sleep_thread(fsg);
+               if (rc)
+                       return rc;
+       }
+
+       return -EIO;            // No default reply
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int do_synchronize_cache(struct fsg_dev *fsg)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       int             rc;
+
+       /* We ignore the requested LBA and write out all file's
+        * dirty data buffers. */
+       rc = fsg_lun_fsync_sub(curlun);
+       if (rc)
+               curlun->sense_data = SS_WRITE_ERROR;
+       return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static void invalidate_sub(struct fsg_lun *curlun)
+{
+       struct file     *filp = curlun->filp;
+       struct inode    *inode = filp->f_path.dentry->d_inode;
+       unsigned long   rc;
+
+       rc = invalidate_mapping_pages(inode->i_mapping, 0, -1);
+       VLDBG(curlun, "invalidate_inode_pages -> %ld\n", rc);
+}
+
+static int do_verify(struct fsg_dev *fsg)
+{
+       struct fsg_lun          *curlun = fsg->curlun;
+       u32                     lba;
+       u32                     verification_length;
+       struct fsg_buffhd       *bh = fsg->next_buffhd_to_fill;
+       loff_t                  file_offset, file_offset_tmp;
+       u32                     amount_left;
+       unsigned int            amount;
+       ssize_t                 nread;
+
+       /* Get the starting Logical Block Address and check that it's
+        * not too big */
+       lba = get_unaligned_be32(&fsg->cmnd[2]);
+       if (lba >= curlun->num_sectors) {
+               curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+               return -EINVAL;
+       }
+
+       /* We allow DPO (Disable Page Out = don't save data in the
+        * cache) but we don't implement it. */
+       if ((fsg->cmnd[1] & ~0x10) != 0) {
+               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+               return -EINVAL;
+       }
+
+       verification_length = get_unaligned_be16(&fsg->cmnd[7]);
+       if (unlikely(verification_length == 0))
+               return -EIO;            // No default reply
+
+       /* Prepare to carry out the file verify */
+       amount_left = verification_length << 9;
+       file_offset = ((loff_t) lba) << 9;
+
+       /* Write out all the dirty buffers before invalidating them */
+       fsg_lun_fsync_sub(curlun);
+       if (signal_pending(current))
+               return -EINTR;
+
+       invalidate_sub(curlun);
+       if (signal_pending(current))
+               return -EINTR;
+
+       /* Just try to read the requested blocks */
+       while (amount_left > 0) {
+
+               /* Figure out how much we need to read:
+                * Try to read the remaining amount, but not more than
+                * the buffer size.
+                * And don't try to read past the end of the file.
+                * If this means reading 0 then we were asked to read
+                * past the end of file. */
+               amount = min((unsigned int) amount_left, mod_data.buflen);
+               amount = min((loff_t) amount,
+                               curlun->file_length - file_offset);
+               if (amount == 0) {
+                       curlun->sense_data =
+                                       SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+                       curlun->sense_data_info = file_offset >> 9;
+                       curlun->info_valid = 1;
+                       break;
+               }
+
+               /* Perform the read */
+               file_offset_tmp = file_offset;
+               nread = vfs_read(curlun->filp,
+                               (char __user *) bh->buf,
+                               amount, &file_offset_tmp);
+               VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
+                               (unsigned long long) file_offset,
+                               (int) nread);
+               if (signal_pending(current))
+                       return -EINTR;
+
+               if (nread < 0) {
+                       LDBG(curlun, "error in file verify: %d\n",
+                                       (int) nread);
+                       nread = 0;
+               } else if (nread < amount) {
+                       LDBG(curlun, "partial file verify: %d/%u\n",
+                                       (int) nread, amount);
+                       nread -= (nread & 511); // Round down to a sector
+               }
+               if (nread == 0) {
+                       curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
+                       curlun->sense_data_info = file_offset >> 9;
+                       curlun->info_valid = 1;
+                       break;
+               }
+               file_offset += nread;
+               amount_left -= nread;
+       }
+       return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int do_inquiry(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       u8      *buf = (u8 *) bh->buf;
+
+       static char vendor_id[] = "Linux   ";
+       static char product_disk_id[] = "File-Stor Gadget";
+       static char product_cdrom_id[] = "File-CD Gadget  ";
+
+       if (!fsg->curlun) {             // Unsupported LUNs are okay
+               fsg->bad_lun_okay = 1;
+               memset(buf, 0, 36);
+               buf[0] = 0x7f;          // Unsupported, no device-type
+               buf[4] = 31;            // Additional length
+               return 36;
+       }
+
+       memset(buf, 0, 8);
+       buf[0] = (mod_data.cdrom ? TYPE_CDROM : TYPE_DISK);
+       if (mod_data.removable)
+               buf[1] = 0x80;
+       buf[2] = 2;             // ANSI SCSI level 2
+       buf[3] = 2;             // SCSI-2 INQUIRY data format
+       buf[4] = 31;            // Additional length
+                               // No special options
+       sprintf(buf + 8, "%-8s%-16s%04x", vendor_id,
+                       (mod_data.cdrom ? product_cdrom_id :
+                               product_disk_id),
+                       mod_data.release);
+       return 36;
+}
+
+
+static int do_request_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       u8              *buf = (u8 *) bh->buf;
+       u32             sd, sdinfo;
+       int             valid;
+
+       /*
+        * From the SCSI-2 spec., section 7.9 (Unit attention condition):
+        *
+        * If a REQUEST SENSE command is received from an initiator
+        * with a pending unit attention condition (before the target
+        * generates the contingent allegiance condition), then the
+        * target shall either:
+        *   a) report any pending sense data and preserve the unit
+        *      attention condition on the logical unit, or,
+        *   b) report the unit attention condition, may discard any
+        *      pending sense data, and clear the unit attention
+        *      condition on the logical unit for that initiator.
+        *
+        * FSG normally uses option a); enable this code to use option b).
+        */
+#if 0
+       if (curlun && curlun->unit_attention_data != SS_NO_SENSE) {
+               curlun->sense_data = curlun->unit_attention_data;
+               curlun->unit_attention_data = SS_NO_SENSE;
+       }
+#endif
+
+       if (!curlun) {          // Unsupported LUNs are okay
+               fsg->bad_lun_okay = 1;
+               sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
+               sdinfo = 0;
+               valid = 0;
+       } else {
+               sd = curlun->sense_data;
+               sdinfo = curlun->sense_data_info;
+               valid = curlun->info_valid << 7;
+               curlun->sense_data = SS_NO_SENSE;
+               curlun->sense_data_info = 0;
+               curlun->info_valid = 0;
+       }
+
+       memset(buf, 0, 18);
+       buf[0] = valid | 0x70;                  // Valid, current error
+       buf[2] = SK(sd);
+       put_unaligned_be32(sdinfo, &buf[3]);    /* Sense information */
+       buf[7] = 18 - 8;                        // Additional sense length
+       buf[12] = ASC(sd);
+       buf[13] = ASCQ(sd);
+       return 18;
+}
+
+
+static int do_read_capacity(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       u32             lba = get_unaligned_be32(&fsg->cmnd[2]);
+       int             pmi = fsg->cmnd[8];
+       u8              *buf = (u8 *) bh->buf;
+
+       /* Check the PMI and LBA fields */
+       if (pmi > 1 || (pmi == 0 && lba != 0)) {
+               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+               return -EINVAL;
+       }
+
+       put_unaligned_be32(curlun->num_sectors - 1, &buf[0]);
+                                               /* Max logical block */
+       put_unaligned_be32(512, &buf[4]);       /* Block length */
+       return 8;
+}
+
+
+static int do_read_header(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       int             msf = fsg->cmnd[1] & 0x02;
+       u32             lba = get_unaligned_be32(&fsg->cmnd[2]);
+       u8              *buf = (u8 *) bh->buf;
+
+       if ((fsg->cmnd[1] & ~0x02) != 0) {              /* Mask away MSF */
+               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+               return -EINVAL;
+       }
+       if (lba >= curlun->num_sectors) {
+               curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
+               return -EINVAL;
+       }
+
+       memset(buf, 0, 8);
+       buf[0] = 0x01;          /* 2048 bytes of user data, rest is EC */
+       store_cdrom_address(&buf[4], msf, lba);
+       return 8;
+}
+
+
+static int do_read_toc(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       int             msf = fsg->cmnd[1] & 0x02;
+       int             start_track = fsg->cmnd[6];
+       u8              *buf = (u8 *) bh->buf;
+
+       if ((fsg->cmnd[1] & ~0x02) != 0 ||              /* Mask away MSF */
+                       start_track > 1) {
+               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+               return -EINVAL;
+       }
+
+       memset(buf, 0, 20);
+       buf[1] = (20-2);                /* TOC data length */
+       buf[2] = 1;                     /* First track number */
+       buf[3] = 1;                     /* Last track number */
+       buf[5] = 0x16;                  /* Data track, copying allowed */
+       buf[6] = 0x01;                  /* Only track is number 1 */
+       store_cdrom_address(&buf[8], msf, 0);
+
+       buf[13] = 0x16;                 /* Lead-out track is data */
+       buf[14] = 0xAA;                 /* Lead-out track number */
+       store_cdrom_address(&buf[16], msf, curlun->num_sectors);
+       return 20;
+}
+
+
+static int do_mode_sense(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       int             mscmnd = fsg->cmnd[0];
+       u8              *buf = (u8 *) bh->buf;
+       u8              *buf0 = buf;
+       int             pc, page_code;
+       int             changeable_values, all_pages;
+       int             valid_page = 0;
+       int             len, limit;
+
+       if ((fsg->cmnd[1] & ~0x08) != 0) {              // Mask away DBD
+               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+               return -EINVAL;
+       }
+       pc = fsg->cmnd[2] >> 6;
+       page_code = fsg->cmnd[2] & 0x3f;
+       if (pc == 3) {
+               curlun->sense_data = SS_SAVING_PARAMETERS_NOT_SUPPORTED;
+               return -EINVAL;
+       }
+       changeable_values = (pc == 1);
+       all_pages = (page_code == 0x3f);
+
+       /* Write the mode parameter header.  Fixed values are: default
+        * medium type, no cache control (DPOFUA), and no block descriptors.
+        * The only variable value is the WriteProtect bit.  We will fill in
+        * the mode data length later. */
+       memset(buf, 0, 8);
+       if (mscmnd == SC_MODE_SENSE_6) {
+               buf[2] = (curlun->ro ? 0x80 : 0x00);            // WP, DPOFUA
+               buf += 4;
+               limit = 255;
+       } else {                        // SC_MODE_SENSE_10
+               buf[3] = (curlun->ro ? 0x80 : 0x00);            // WP, DPOFUA
+               buf += 8;
+               limit = 65535;          // Should really be mod_data.buflen
+       }
+
+       /* No block descriptors */
+
+       /* The mode pages, in numerical order.  The only page we support
+        * is the Caching page. */
+       if (page_code == 0x08 || all_pages) {
+               valid_page = 1;
+               buf[0] = 0x08;          // Page code
+               buf[1] = 10;            // Page length
+               memset(buf+2, 0, 10);   // None of the fields are changeable
+
+               if (!changeable_values) {
+                       buf[2] = 0x04;  // Write cache enable,
+                                       // Read cache not disabled
+                                       // No cache retention priorities
+                       put_unaligned_be16(0xffff, &buf[4]);
+                                       /* Don't disable prefetch */
+                                       /* Minimum prefetch = 0 */
+                       put_unaligned_be16(0xffff, &buf[8]);
+                                       /* Maximum prefetch */
+                       put_unaligned_be16(0xffff, &buf[10]);
+                                       /* Maximum prefetch ceiling */
+               }
+               buf += 12;
+       }
+
+       /* Check that a valid page was requested and the mode data length
+        * isn't too long. */
+       len = buf - buf0;
+       if (!valid_page || len > limit) {
+               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+               return -EINVAL;
+       }
+
+       /*  Store the mode data length */
+       if (mscmnd == SC_MODE_SENSE_6)
+               buf0[0] = len - 1;
+       else
+               put_unaligned_be16(len - 2, buf0);
+       return len;
+}
+
+
+static int do_start_stop(struct fsg_dev *fsg)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       int             loej, start;
+
+       if (!mod_data.removable) {
+               curlun->sense_data = SS_INVALID_COMMAND;
+               return -EINVAL;
+       }
+
+       // int immed = fsg->cmnd[1] & 0x01;
+       loej = fsg->cmnd[4] & 0x02;
+       start = fsg->cmnd[4] & 0x01;
+
+#ifdef CONFIG_USB_FILE_STORAGE_TEST
+       if ((fsg->cmnd[1] & ~0x01) != 0 ||              // Mask away Immed
+                       (fsg->cmnd[4] & ~0x03) != 0) {  // Mask LoEj, Start
+               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+               return -EINVAL;
+       }
+
+       if (!start) {
+
+               /* Are we allowed to unload the media? */
+               if (curlun->prevent_medium_removal) {
+                       LDBG(curlun, "unload attempt prevented\n");
+                       curlun->sense_data = SS_MEDIUM_REMOVAL_PREVENTED;
+                       return -EINVAL;
+               }
+               if (loej) {             // Simulate an unload/eject
+                       up_read(&fsg->filesem);
+                       down_write(&fsg->filesem);
+                       fsg_lun_close(curlun);
+                       up_write(&fsg->filesem);
+                       down_read(&fsg->filesem);
+               }
+       } else {
+
+               /* Our emulation doesn't support mounting; the medium is
+                * available for use as soon as it is loaded. */
+               if (!fsg_lun_is_open(curlun)) {
+                       curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
+                       return -EINVAL;
+               }
+       }
+#endif
+       return 0;
+}
+
+
+static int do_prevent_allow(struct fsg_dev *fsg)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       int             prevent;
+
+       if (!mod_data.removable) {
+               curlun->sense_data = SS_INVALID_COMMAND;
+               return -EINVAL;
+       }
+
+       prevent = fsg->cmnd[4] & 0x01;
+       if ((fsg->cmnd[4] & ~0x01) != 0) {              // Mask away Prevent
+               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+               return -EINVAL;
+       }
+
+       if (curlun->prevent_medium_removal && !prevent)
+               fsg_lun_fsync_sub(curlun);
+       curlun->prevent_medium_removal = prevent;
+       return 0;
+}
+
+
+static int do_read_format_capacities(struct fsg_dev *fsg,
+                       struct fsg_buffhd *bh)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+       u8              *buf = (u8 *) bh->buf;
+
+       buf[0] = buf[1] = buf[2] = 0;
+       buf[3] = 8;             // Only the Current/Maximum Capacity Descriptor
+       buf += 4;
+
+       put_unaligned_be32(curlun->num_sectors, &buf[0]);
+                                               /* Number of blocks */
+       put_unaligned_be32(512, &buf[4]);       /* Block length */
+       buf[4] = 0x02;                          /* Current capacity */
+       return 12;
+}
+
+
+static int do_mode_select(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       struct fsg_lun  *curlun = fsg->curlun;
+
+       /* We don't support MODE SELECT */
+       curlun->sense_data = SS_INVALID_COMMAND;
+       return -EINVAL;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int halt_bulk_in_endpoint(struct fsg_dev *fsg)
+{
+       int     rc;
+
+       rc = fsg_set_halt(fsg, fsg->bulk_in);
+       if (rc == -EAGAIN)
+               VDBG(fsg, "delayed bulk-in endpoint halt\n");
+       while (rc != 0) {
+               if (rc != -EAGAIN) {
+                       WARNING(fsg, "usb_ep_set_halt -> %d\n", rc);
+                       rc = 0;
+                       break;
+               }
+
+               /* Wait for a short time and then try again */
+               if (msleep_interruptible(100) != 0)
+                       return -EINTR;
+               rc = usb_ep_set_halt(fsg->bulk_in);
+       }
+       return rc;
+}
+
+static int wedge_bulk_in_endpoint(struct fsg_dev *fsg)
+{
+       int     rc;
+
+       DBG(fsg, "bulk-in set wedge\n");
+       rc = usb_ep_set_wedge(fsg->bulk_in);
+       if (rc == -EAGAIN)
+               VDBG(fsg, "delayed bulk-in endpoint wedge\n");
+       while (rc != 0) {
+               if (rc != -EAGAIN) {
+                       WARNING(fsg, "usb_ep_set_wedge -> %d\n", rc);
+                       rc = 0;
+                       break;
+               }
+
+               /* Wait for a short time and then try again */
+               if (msleep_interruptible(100) != 0)
+                       return -EINTR;
+               rc = usb_ep_set_wedge(fsg->bulk_in);
+       }
+       return rc;
+}
+
+static int pad_with_zeros(struct fsg_dev *fsg)
+{
+       struct fsg_buffhd       *bh = fsg->next_buffhd_to_fill;
+       u32                     nkeep = bh->inreq->length;
+       u32                     nsend;
+       int                     rc;
+
+       bh->state = BUF_STATE_EMPTY;            // For the first iteration
+       fsg->usb_amount_left = nkeep + fsg->residue;
+       while (fsg->usb_amount_left > 0) {
+
+               /* Wait for the next buffer to be free */
+               while (bh->state != BUF_STATE_EMPTY) {
+                       rc = sleep_thread(fsg);
+                       if (rc)
+                               return rc;
+               }
+
+               nsend = min(fsg->usb_amount_left, (u32) mod_data.buflen);
+               memset(bh->buf + nkeep, 0, nsend - nkeep);
+               bh->inreq->length = nsend;
+               bh->inreq->zero = 0;
+               start_transfer(fsg, fsg->bulk_in, bh->inreq,
+                               &bh->inreq_busy, &bh->state);
+               bh = fsg->next_buffhd_to_fill = bh->next;
+               fsg->usb_amount_left -= nsend;
+               nkeep = 0;
+       }
+       return 0;
+}
+
+static int throw_away_data(struct fsg_dev *fsg)
+{
+       struct fsg_buffhd       *bh;
+       u32                     amount;
+       int                     rc;
+
+       while ((bh = fsg->next_buffhd_to_drain)->state != BUF_STATE_EMPTY ||
+                       fsg->usb_amount_left > 0) {
+
+               /* Throw away the data in a filled buffer */
+               if (bh->state == BUF_STATE_FULL) {
+                       smp_rmb();
+                       bh->state = BUF_STATE_EMPTY;
+                       fsg->next_buffhd_to_drain = bh->next;
+
+                       /* A short packet or an error ends everything */
+                       if (bh->outreq->actual != bh->outreq->length ||
+                                       bh->outreq->status != 0) {
+                               raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
+                               return -EINTR;
+                       }
+                       continue;
+               }
+
+               /* Try to submit another request if we need one */
+               bh = fsg->next_buffhd_to_fill;
+               if (bh->state == BUF_STATE_EMPTY && fsg->usb_amount_left > 0) {
+                       amount = min(fsg->usb_amount_left,
+                                       (u32) mod_data.buflen);
+
+                       /* amount is always divisible by 512, hence by
+                        * the bulk-out maxpacket size */
+                       bh->outreq->length = bh->bulk_out_intended_length =
+                                       amount;
+                       bh->outreq->short_not_ok = 1;
+                       start_transfer(fsg, fsg->bulk_out, bh->outreq,
+                                       &bh->outreq_busy, &bh->state);
+                       fsg->next_buffhd_to_fill = bh->next;
+                       fsg->usb_amount_left -= amount;
+                       continue;
+               }
+
+               /* Otherwise wait for something to happen */
+               rc = sleep_thread(fsg);
+               if (rc)
+                       return rc;
+       }
+       return 0;
+}
+
+
+static int finish_reply(struct fsg_dev *fsg)
+{
+       struct fsg_buffhd       *bh = fsg->next_buffhd_to_fill;
+       int                     rc = 0;
+
+       switch (fsg->data_dir) {
+       case DATA_DIR_NONE:
+               break;                  // Nothing to send
+
+       /* If we don't know whether the host wants to read or write,
+        * this must be CB or CBI with an unknown command.  We mustn't
+        * try to send or receive any data.  So stall both bulk pipes
+        * if we can and wait for a reset. */
+       case DATA_DIR_UNKNOWN:
+               if (mod_data.can_stall) {
+                       fsg_set_halt(fsg, fsg->bulk_out);
+                       rc = halt_bulk_in_endpoint(fsg);
+               }
+               break;
+
+       /* All but the last buffer of data must have already been sent */
+       case DATA_DIR_TO_HOST:
+               if (fsg->data_size == 0)
+                       ;               // Nothing to send
+
+               /* If there's no residue, simply send the last buffer */
+               else if (fsg->residue == 0) {
+                       bh->inreq->zero = 0;
+                       start_transfer(fsg, fsg->bulk_in, bh->inreq,
+                                       &bh->inreq_busy, &bh->state);
+                       fsg->next_buffhd_to_fill = bh->next;
+               }
+
+               /* There is a residue.  For CB and CBI, simply mark the end
+                * of the data with a short packet.  However, if we are
+                * allowed to stall, there was no data at all (residue ==
+                * data_size), and the command failed (invalid LUN or
+                * sense data is set), then halt the bulk-in endpoint
+                * instead. */
+               else if (!transport_is_bbb()) {
+                       if (mod_data.can_stall &&
+                                       fsg->residue == fsg->data_size &&
+       (!fsg->curlun || fsg->curlun->sense_data != SS_NO_SENSE)) {
+                               bh->state = BUF_STATE_EMPTY;
+                               rc = halt_bulk_in_endpoint(fsg);
+                       } else {
+                               bh->inreq->zero = 1;
+                               start_transfer(fsg, fsg->bulk_in, bh->inreq,
+                                               &bh->inreq_busy, &bh->state);
+                               fsg->next_buffhd_to_fill = bh->next;
+                       }
+               }
+
+               /* For Bulk-only, if we're allowed to stall then send the
+                * short packet and halt the bulk-in endpoint.  If we can't
+                * stall, pad out the remaining data with 0's. */
+               else {
+                       if (mod_data.can_stall) {
+                               bh->inreq->zero = 1;
+                               start_transfer(fsg, fsg->bulk_in, bh->inreq,
+                                               &bh->inreq_busy, &bh->state);
+                               fsg->next_buffhd_to_fill = bh->next;
+                               rc = halt_bulk_in_endpoint(fsg);
+                       } else
+                               rc = pad_with_zeros(fsg);
+               }
+               break;
+
+       /* We have processed all we want from the data the host has sent.
+        * There may still be outstanding bulk-out requests. */
+       case DATA_DIR_FROM_HOST:
+               if (fsg->residue == 0)
+                       ;               // Nothing to receive
+
+               /* Did the host stop sending unexpectedly early? */
+               else if (fsg->short_packet_received) {
+                       raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
+                       rc = -EINTR;
+               }
+
+               /* We haven't processed all the incoming data.  Even though
+                * we may be allowed to stall, doing so would cause a race.
+                * The controller may already have ACK'ed all the remaining
+                * bulk-out packets, in which case the host wouldn't see a
+                * STALL.  Not realizing the endpoint was halted, it wouldn't
+                * clear the halt -- leading to problems later on. */
+#if 0
+               else if (mod_data.can_stall) {
+                       fsg_set_halt(fsg, fsg->bulk_out);
+                       raise_exception(fsg, FSG_STATE_ABORT_BULK_OUT);
+                       rc = -EINTR;
+               }
+#endif
+
+               /* We can't stall.  Read in the excess data and throw it
+                * all away. */
+               else
+                       rc = throw_away_data(fsg);
+               break;
+       }
+       return rc;
+}
+
+
+static int send_status(struct fsg_dev *fsg)
+{
+       struct fsg_lun          *curlun = fsg->curlun;
+       struct fsg_buffhd       *bh;
+       int                     rc;
+       u8                      status = USB_STATUS_PASS;
+       u32                     sd, sdinfo = 0;
+
+       /* Wait for the next buffer to become available */
+       bh = fsg->next_buffhd_to_fill;
+       while (bh->state != BUF_STATE_EMPTY) {
+               rc = sleep_thread(fsg);
+               if (rc)
+                       return rc;
+       }
+
+       if (curlun) {
+               sd = curlun->sense_data;
+               sdinfo = curlun->sense_data_info;
+       } else if (fsg->bad_lun_okay)
+               sd = SS_NO_SENSE;
+       else
+               sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
+
+       if (fsg->phase_error) {
+               DBG(fsg, "sending phase-error status\n");
+               status = USB_STATUS_PHASE_ERROR;
+               sd = SS_INVALID_COMMAND;
+       } else if (sd != SS_NO_SENSE) {
+               DBG(fsg, "sending command-failure status\n");
+               status = USB_STATUS_FAIL;
+               VDBG(fsg, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
+                               "  info x%x\n",
+                               SK(sd), ASC(sd), ASCQ(sd), sdinfo);
+       }
+
+       if (transport_is_bbb()) {
+               struct bulk_cs_wrap     *csw = bh->buf;
+
+               /* Store and send the Bulk-only CSW */
+               csw->Signature = cpu_to_le32(USB_BULK_CS_SIG);
+               csw->Tag = fsg->tag;
+               csw->Residue = cpu_to_le32(fsg->residue);
+               csw->Status = status;
+
+               bh->inreq->length = USB_BULK_CS_WRAP_LEN;
+               bh->inreq->zero = 0;
+               start_transfer(fsg, fsg->bulk_in, bh->inreq,
+                               &bh->inreq_busy, &bh->state);
+
+       } else if (mod_data.transport_type == USB_PR_CB) {
+
+               /* Control-Bulk transport has no status phase! */
+               return 0;
+
+       } else {                        // USB_PR_CBI
+               struct interrupt_data   *buf = bh->buf;
+
+               /* Store and send the Interrupt data.  UFI sends the ASC
+                * and ASCQ bytes.  Everything else sends a Type (which
+                * is always 0) and the status Value. */
+               if (mod_data.protocol_type == USB_SC_UFI) {
+                       buf->bType = ASC(sd);
+                       buf->bValue = ASCQ(sd);
+               } else {
+                       buf->bType = 0;
+                       buf->bValue = status;
+               }
+               fsg->intreq->length = CBI_INTERRUPT_DATA_LEN;
+
+               fsg->intr_buffhd = bh;          // Point to the right buffhd
+               fsg->intreq->buf = bh->inreq->buf;
+               fsg->intreq->context = bh;
+               start_transfer(fsg, fsg->intr_in, fsg->intreq,
+                               &fsg->intreq_busy, &bh->state);
+       }
+
+       fsg->next_buffhd_to_fill = bh->next;
+       return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+/* Check whether the command is properly formed and whether its data size
+ * and direction agree with the values we already have. */
+static int check_command(struct fsg_dev *fsg, int cmnd_size,
+               enum data_direction data_dir, unsigned int mask,
+               int needs_medium, const char *name)
+{
+       int                     i;
+       int                     lun = fsg->cmnd[1] >> 5;
+       static const char       dirletter[4] = {'u', 'o', 'i', 'n'};
+       char                    hdlen[20];
+       struct fsg_lun          *curlun;
+
+       /* Adjust the expected cmnd_size for protocol encapsulation padding.
+        * Transparent SCSI doesn't pad. */
+       if (protocol_is_scsi())
+               ;
+
+       /* There's some disagreement as to whether RBC pads commands or not.
+        * We'll play it safe and accept either form. */
+       else if (mod_data.protocol_type == USB_SC_RBC) {
+               if (fsg->cmnd_size == 12)
+                       cmnd_size = 12;
+
+       /* All the other protocols pad to 12 bytes */
+       } else
+               cmnd_size = 12;
+
+       hdlen[0] = 0;
+       if (fsg->data_dir != DATA_DIR_UNKNOWN)
+               sprintf(hdlen, ", H%c=%u", dirletter[(int) fsg->data_dir],
+                               fsg->data_size);
+       VDBG(fsg, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
+                       name, cmnd_size, dirletter[(int) data_dir],
+                       fsg->data_size_from_cmnd, fsg->cmnd_size, hdlen);
+
+       /* We can't reply at all until we know the correct data direction
+        * and size. */
+       if (fsg->data_size_from_cmnd == 0)
+               data_dir = DATA_DIR_NONE;
+       if (fsg->data_dir == DATA_DIR_UNKNOWN) {        // CB or CBI
+               fsg->data_dir = data_dir;
+               fsg->data_size = fsg->data_size_from_cmnd;
+
+       } else {                                        // Bulk-only
+               if (fsg->data_size < fsg->data_size_from_cmnd) {
+
+                       /* Host data size < Device data size is a phase error.
+                        * Carry out the command, but only transfer as much
+                        * as we are allowed. */
+                       fsg->data_size_from_cmnd = fsg->data_size;
+                       fsg->phase_error = 1;
+               }
+       }
+       fsg->residue = fsg->usb_amount_left = fsg->data_size;
+
+       /* Conflicting data directions is a phase error */
+       if (fsg->data_dir != data_dir && fsg->data_size_from_cmnd > 0) {
+               fsg->phase_error = 1;
+               return -EINVAL;
+       }
+
+       /* Verify the length of the command itself */
+       if (cmnd_size != fsg->cmnd_size) {
+
+               /* Special case workaround: There are plenty of buggy SCSI
+                * implementations. Many have issues with cbw->Length
+                * field passing a wrong command size. For those cases we
+                * always try to work around the problem by using the length
+                * sent by the host side provided it is at least as large
+                * as the correct command length.
+                * Examples of such cases would be MS-Windows, which issues
+                * REQUEST SENSE with cbw->Length == 12 where it should
+                * be 6, and xbox360 issuing INQUIRY, TEST UNIT READY and
+                * REQUEST SENSE with cbw->Length == 10 where it should
+                * be 6 as well.
+                */
+               if (cmnd_size <= fsg->cmnd_size) {
+                       DBG(fsg, "%s is buggy! Expected length %d "
+                                       "but we got %d\n", name,
+                                       cmnd_size, fsg->cmnd_size);
+                       cmnd_size = fsg->cmnd_size;
+               } else {
+                       fsg->phase_error = 1;
+                       return -EINVAL;
+               }
+       }
+
+       /* Check that the LUN values are consistent */
+       if (transport_is_bbb()) {
+               if (fsg->lun != lun)
+                       DBG(fsg, "using LUN %d from CBW, "
+                                       "not LUN %d from CDB\n",
+                                       fsg->lun, lun);
+       } else
+               fsg->lun = lun;         // Use LUN from the command
+
+       /* Check the LUN */
+       if (fsg->lun >= 0 && fsg->lun < fsg->nluns) {
+               fsg->curlun = curlun = &fsg->luns[fsg->lun];
+               if (fsg->cmnd[0] != SC_REQUEST_SENSE) {
+                       curlun->sense_data = SS_NO_SENSE;
+                       curlun->sense_data_info = 0;
+                       curlun->info_valid = 0;
+               }
+       } else {
+               fsg->curlun = curlun = NULL;
+               fsg->bad_lun_okay = 0;
+
+               /* INQUIRY and REQUEST SENSE commands are explicitly allowed
+                * to use unsupported LUNs; all others may not. */
+               if (fsg->cmnd[0] != SC_INQUIRY &&
+                               fsg->cmnd[0] != SC_REQUEST_SENSE) {
+                       DBG(fsg, "unsupported LUN %d\n", fsg->lun);
+                       return -EINVAL;
+               }
+       }
+
+       /* If a unit attention condition exists, only INQUIRY and
+        * REQUEST SENSE commands are allowed; anything else must fail. */
+       if (curlun && curlun->unit_attention_data != SS_NO_SENSE &&
+                       fsg->cmnd[0] != SC_INQUIRY &&
+                       fsg->cmnd[0] != SC_REQUEST_SENSE) {
+               curlun->sense_data = curlun->unit_attention_data;
+               curlun->unit_attention_data = SS_NO_SENSE;
+               return -EINVAL;
+       }
+
+       /* Check that only command bytes listed in the mask are non-zero */
+       fsg->cmnd[1] &= 0x1f;                   // Mask away the LUN
+       for (i = 1; i < cmnd_size; ++i) {
+               if (fsg->cmnd[i] && !(mask & (1 << i))) {
+                       if (curlun)
+                               curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
+                       return -EINVAL;
+               }
+       }
+
+       /* If the medium isn't mounted and the command needs to access
+        * it, return an error. */
+       if (curlun && !fsg_lun_is_open(curlun) && needs_medium) {
+               curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+
+static int do_scsi_command(struct fsg_dev *fsg)
+{
+       struct fsg_buffhd       *bh;
+       int                     rc;
+       int                     reply = -EINVAL;
+       int                     i;
+       static char             unknown[16];
+
+       dump_cdb(fsg);
+
+       /* Wait for the next buffer to become available for data or status */
+       bh = fsg->next_buffhd_to_drain = fsg->next_buffhd_to_fill;
+       while (bh->state != BUF_STATE_EMPTY) {
+               rc = sleep_thread(fsg);
+               if (rc)
+                       return rc;
+       }
+       fsg->phase_error = 0;
+       fsg->short_packet_received = 0;
+
+       down_read(&fsg->filesem);       // We're using the backing file
+       switch (fsg->cmnd[0]) {
+
+       case SC_INQUIRY:
+               fsg->data_size_from_cmnd = fsg->cmnd[4];
+               if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
+                               (1<<4), 0,
+                               "INQUIRY")) == 0)
+                       reply = do_inquiry(fsg, bh);
+               break;
+
+       case SC_MODE_SELECT_6:
+               fsg->data_size_from_cmnd = fsg->cmnd[4];
+               if ((reply = check_command(fsg, 6, DATA_DIR_FROM_HOST,
+                               (1<<1) | (1<<4), 0,
+                               "MODE SELECT(6)")) == 0)
+                       reply = do_mode_select(fsg, bh);
+               break;
+
+       case SC_MODE_SELECT_10:
+               fsg->data_size_from_cmnd = get_unaligned_be16(&fsg->cmnd[7]);
+               if ((reply = check_command(fsg, 10, DATA_DIR_FROM_HOST,
+                               (1<<1) | (3<<7), 0,
+                               "MODE SELECT(10)")) == 0)
+                       reply = do_mode_select(fsg, bh);
+               break;
+
+       case SC_MODE_SENSE_6:
+               fsg->data_size_from_cmnd = fsg->cmnd[4];
+               if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
+                               (1<<1) | (1<<2) | (1<<4), 0,
+                               "MODE SENSE(6)")) == 0)
+                       reply = do_mode_sense(fsg, bh);
+               break;
+
+       case SC_MODE_SENSE_10:
+               fsg->data_size_from_cmnd = get_unaligned_be16(&fsg->cmnd[7]);
+               if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+                               (1<<1) | (1<<2) | (3<<7), 0,
+                               "MODE SENSE(10)")) == 0)
+                       reply = do_mode_sense(fsg, bh);
+               break;
+
+       case SC_PREVENT_ALLOW_MEDIUM_REMOVAL:
+               fsg->data_size_from_cmnd = 0;
+               if ((reply = check_command(fsg, 6, DATA_DIR_NONE,
+                               (1<<4), 0,
+                               "PREVENT-ALLOW MEDIUM REMOVAL")) == 0)
+                       reply = do_prevent_allow(fsg);
+               break;
+
+       case SC_READ_6:
+               i = fsg->cmnd[4];
+               fsg->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
+               if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
+                               (7<<1) | (1<<4), 1,
+                               "READ(6)")) == 0)
+                       reply = do_read(fsg);
+               break;
+
+       case SC_READ_10:
+               fsg->data_size_from_cmnd =
+                               get_unaligned_be16(&fsg->cmnd[7]) << 9;
+               if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+                               (1<<1) | (0xf<<2) | (3<<7), 1,
+                               "READ(10)")) == 0)
+                       reply = do_read(fsg);
+               break;
+
+       case SC_READ_12:
+               fsg->data_size_from_cmnd =
+                               get_unaligned_be32(&fsg->cmnd[6]) << 9;
+               if ((reply = check_command(fsg, 12, DATA_DIR_TO_HOST,
+                               (1<<1) | (0xf<<2) | (0xf<<6), 1,
+                               "READ(12)")) == 0)
+                       reply = do_read(fsg);
+               break;
+
+       case SC_READ_CAPACITY:
+               fsg->data_size_from_cmnd = 8;
+               if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+                               (0xf<<2) | (1<<8), 1,
+                               "READ CAPACITY")) == 0)
+                       reply = do_read_capacity(fsg, bh);
+               break;
+
+       case SC_READ_HEADER:
+               if (!mod_data.cdrom)
+                       goto unknown_cmnd;
+               fsg->data_size_from_cmnd = get_unaligned_be16(&fsg->cmnd[7]);
+               if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+                               (3<<7) | (0x1f<<1), 1,
+                               "READ HEADER")) == 0)
+                       reply = do_read_header(fsg, bh);
+               break;
+
+       case SC_READ_TOC:
+               if (!mod_data.cdrom)
+                       goto unknown_cmnd;
+               fsg->data_size_from_cmnd = get_unaligned_be16(&fsg->cmnd[7]);
+               if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+                               (7<<6) | (1<<1), 1,
+                               "READ TOC")) == 0)
+                       reply = do_read_toc(fsg, bh);
+               break;
+
+       case SC_READ_FORMAT_CAPACITIES:
+               fsg->data_size_from_cmnd = get_unaligned_be16(&fsg->cmnd[7]);
+               if ((reply = check_command(fsg, 10, DATA_DIR_TO_HOST,
+                               (3<<7), 1,
+                               "READ FORMAT CAPACITIES")) == 0)
+                       reply = do_read_format_capacities(fsg, bh);
+               break;
+
+       case SC_REQUEST_SENSE:
+               fsg->data_size_from_cmnd = fsg->cmnd[4];
+               if ((reply = check_command(fsg, 6, DATA_DIR_TO_HOST,
+                               (1<<4), 0,
+                               "REQUEST SENSE")) == 0)
+                       reply = do_request_sense(fsg, bh);
+               break;
+
+       case SC_START_STOP_UNIT:
+               fsg->data_size_from_cmnd = 0;
+               if ((reply = check_command(fsg, 6, DATA_DIR_NONE,
+                               (1<<1) | (1<<4), 0,
+                               "START-STOP UNIT")) == 0)
+                       reply = do_start_stop(fsg);
+               break;
+
+       case SC_SYNCHRONIZE_CACHE:
+               fsg->data_size_from_cmnd = 0;
+               if ((reply = check_command(fsg, 10, DATA_DIR_NONE,
+                               (0xf<<2) | (3<<7), 1,
+                               "SYNCHRONIZE CACHE")) == 0)
+                       reply = do_synchronize_cache(fsg);
+               break;
+
+       case SC_TEST_UNIT_READY:
+               fsg->data_size_from_cmnd = 0;
+               reply = check_command(fsg, 6, DATA_DIR_NONE,
+                               0, 1,
+                               "TEST UNIT READY");
+               break;
+
+       /* Although optional, this command is used by MS-Windows.  We
+        * support a minimal version: BytChk must be 0. */
+       case SC_VERIFY:
+               fsg->data_size_from_cmnd = 0;
+               if ((reply = check_command(fsg, 10, DATA_DIR_NONE,
+                               (1<<1) | (0xf<<2) | (3<<7), 1,
+                               "VERIFY")) == 0)
+                       reply = do_verify(fsg);
+               break;
+
+       case SC_WRITE_6:
+               i = fsg->cmnd[4];
+               fsg->data_size_from_cmnd = (i == 0 ? 256 : i) << 9;
+               if ((reply = check_command(fsg, 6, DATA_DIR_FROM_HOST,
+                               (7<<1) | (1<<4), 1,
+                               "WRITE(6)")) == 0)
+                       reply = do_write(fsg);
+               break;
+
+       case SC_WRITE_10:
+               fsg->data_size_from_cmnd =
+                               get_unaligned_be16(&fsg->cmnd[7]) << 9;
+               if ((reply = check_command(fsg, 10, DATA_DIR_FROM_HOST,
+                               (1<<1) | (0xf<<2) | (3<<7), 1,
+                               "WRITE(10)")) == 0)
+                       reply = do_write(fsg);
+               break;
+
+       case SC_WRITE_12:
+               fsg->data_size_from_cmnd =
+                               get_unaligned_be32(&fsg->cmnd[6]) << 9;
+               if ((reply = check_command(fsg, 12, DATA_DIR_FROM_HOST,
+                               (1<<1) | (0xf<<2) | (0xf<<6), 1,
+                               "WRITE(12)")) == 0)
+                       reply = do_write(fsg);
+               break;
+
+       /* Some mandatory commands that we recognize but don't implement.
+        * They don't mean much in this setting.  It's left as an exercise
+        * for anyone interested to implement RESERVE and RELEASE in terms
+        * of Posix locks. */
+       case SC_FORMAT_UNIT:
+       case SC_RELEASE:
+       case SC_RESERVE:
+       case SC_SEND_DIAGNOSTIC:
+               // Fall through
+
+       default:
+ unknown_cmnd:
+               fsg->data_size_from_cmnd = 0;
+               sprintf(unknown, "Unknown x%02x", fsg->cmnd[0]);
+               if ((reply = check_command(fsg, fsg->cmnd_size,
+                               DATA_DIR_UNKNOWN, 0xff, 0, unknown)) == 0) {
+                       fsg->curlun->sense_data = SS_INVALID_COMMAND;
+                       reply = -EINVAL;
+               }
+               break;
+       }
+       up_read(&fsg->filesem);
+
+       if (reply == -EINTR || signal_pending(current))
+               return -EINTR;
+
+       /* Set up the single reply buffer for finish_reply() */
+       if (reply == -EINVAL)
+               reply = 0;              // Error reply length
+       if (reply >= 0 && fsg->data_dir == DATA_DIR_TO_HOST) {
+               reply = min((u32) reply, fsg->data_size_from_cmnd);
+               bh->inreq->length = reply;
+               bh->state = BUF_STATE_FULL;
+               fsg->residue -= reply;
+       }                               // Otherwise it's already set
+
+       return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
+{
+       struct usb_request              *req = bh->outreq;
+       struct fsg_bulk_cb_wrap *cbw = req->buf;
+
+       /* Was this a real packet?  Should it be ignored? */
+       if (req->status || test_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags))
+               return -EINVAL;
+
+       /* Is the CBW valid? */
+       if (req->actual != USB_BULK_CB_WRAP_LEN ||
+                       cbw->Signature != cpu_to_le32(
+                               USB_BULK_CB_SIG)) {
+               DBG(fsg, "invalid CBW: len %u sig 0x%x\n",
+                               req->actual,
+                               le32_to_cpu(cbw->Signature));
+
+               /* The Bulk-only spec says we MUST stall the IN endpoint
+                * (6.6.1), so it's unavoidable.  It also says we must
+                * retain this state until the next reset, but there's
+                * no way to tell the controller driver it should ignore
+                * Clear-Feature(HALT) requests.
+                *
+                * We aren't required to halt the OUT endpoint; instead
+                * we can simply accept and discard any data received
+                * until the next reset. */
+               wedge_bulk_in_endpoint(fsg);
+               set_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
+               return -EINVAL;
+       }
+
+       /* Is the CBW meaningful? */
+       if (cbw->Lun >= FSG_MAX_LUNS || cbw->Flags & ~USB_BULK_IN_FLAG ||
+                       cbw->Length <= 0 || cbw->Length > MAX_COMMAND_SIZE) {
+               DBG(fsg, "non-meaningful CBW: lun = %u, flags = 0x%x, "
+                               "cmdlen %u\n",
+                               cbw->Lun, cbw->Flags, cbw->Length);
+
+               /* We can do anything we want here, so let's stall the
+                * bulk pipes if we are allowed to. */
+               if (mod_data.can_stall) {
+                       fsg_set_halt(fsg, fsg->bulk_out);
+                       halt_bulk_in_endpoint(fsg);
+               }
+               return -EINVAL;
+       }
+
+       /* Save the command for later */
+       fsg->cmnd_size = cbw->Length;
+       memcpy(fsg->cmnd, cbw->CDB, fsg->cmnd_size);
+       if (cbw->Flags & USB_BULK_IN_FLAG)
+               fsg->data_dir = DATA_DIR_TO_HOST;
+       else
+               fsg->data_dir = DATA_DIR_FROM_HOST;
+       fsg->data_size = le32_to_cpu(cbw->DataTransferLength);
+       if (fsg->data_size == 0)
+               fsg->data_dir = DATA_DIR_NONE;
+       fsg->lun = cbw->Lun;
+       fsg->tag = cbw->Tag;
+       return 0;
+}
+
+
+static int get_next_command(struct fsg_dev *fsg)
+{
+       struct fsg_buffhd       *bh;
+       int                     rc = 0;
+
+       if (transport_is_bbb()) {
+
+               /* Wait for the next buffer to become available */
+               bh = fsg->next_buffhd_to_fill;
+               while (bh->state != BUF_STATE_EMPTY) {
+                       rc = sleep_thread(fsg);
+                       if (rc)
+                               return rc;
+               }
+
+               /* Queue a request to read a Bulk-only CBW */
+               set_bulk_out_req_length(fsg, bh, USB_BULK_CB_WRAP_LEN);
+               bh->outreq->short_not_ok = 1;
+               start_transfer(fsg, fsg->bulk_out, bh->outreq,
+                               &bh->outreq_busy, &bh->state);
+
+               /* We will drain the buffer in software, which means we
+                * can reuse it for the next filling.  No need to advance
+                * next_buffhd_to_fill. */
+
+               /* Wait for the CBW to arrive */
+               while (bh->state != BUF_STATE_FULL) {
+                       rc = sleep_thread(fsg);
+                       if (rc)
+                               return rc;
+               }
+               smp_rmb();
+               rc = received_cbw(fsg, bh);
+               bh->state = BUF_STATE_EMPTY;
+
+       } else {                // USB_PR_CB or USB_PR_CBI
+
+               /* Wait for the next command to arrive */
+               while (fsg->cbbuf_cmnd_size == 0) {
+                       rc = sleep_thread(fsg);
+                       if (rc)
+                               return rc;
+               }
+
+               /* Is the previous status interrupt request still busy?
+                * The host is allowed to skip reading the status,
+                * so we must cancel it. */
+               if (fsg->intreq_busy)
+                       usb_ep_dequeue(fsg->intr_in, fsg->intreq);
+
+               /* Copy the command and mark the buffer empty */
+               fsg->data_dir = DATA_DIR_UNKNOWN;
+               spin_lock_irq(&fsg->lock);
+               fsg->cmnd_size = fsg->cbbuf_cmnd_size;
+               memcpy(fsg->cmnd, fsg->cbbuf_cmnd, fsg->cmnd_size);
+               fsg->cbbuf_cmnd_size = 0;
+               spin_unlock_irq(&fsg->lock);
+       }
+       return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int enable_endpoint(struct fsg_dev *fsg, struct usb_ep *ep,
+               const struct usb_endpoint_descriptor *d)
+{
+       int     rc;
+
+       ep->driver_data = fsg;
+       rc = usb_ep_enable(ep, d);
+       if (rc)
+               ERROR(fsg, "can't enable %s, result %d\n", ep->name, rc);
+       return rc;
+}
+
+static int alloc_request(struct fsg_dev *fsg, struct usb_ep *ep,
+               struct usb_request **preq)
+{
+       *preq = usb_ep_alloc_request(ep, GFP_ATOMIC);
+       if (*preq)
+               return 0;
+       ERROR(fsg, "can't allocate request for %s\n", ep->name);
+       return -ENOMEM;
+}
+
+/*
+ * Reset interface setting and re-init endpoint state (toggle etc).
+ * Call with altsetting < 0 to disable the interface.  The only other
+ * available altsetting is 0, which enables the interface.
+ */
+static int do_set_interface(struct fsg_dev *fsg, int altsetting)
+{
+       int     rc = 0;
+       int     i;
+       const struct usb_endpoint_descriptor    *d;
+
+       if (fsg->running)
+               DBG(fsg, "reset interface\n");
+
+reset:
+       /* Deallocate the requests */
+       for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+               struct fsg_buffhd *bh = &fsg->buffhds[i];
+
+               if (bh->inreq) {
+                       usb_ep_free_request(fsg->bulk_in, bh->inreq);
+                       bh->inreq = NULL;
+               }
+               if (bh->outreq) {
+                       usb_ep_free_request(fsg->bulk_out, bh->outreq);
+                       bh->outreq = NULL;
+               }
+       }
+       if (fsg->intreq) {
+               usb_ep_free_request(fsg->intr_in, fsg->intreq);
+               fsg->intreq = NULL;
+       }
+
+       /* Disable the endpoints */
+       if (fsg->bulk_in_enabled) {
+               usb_ep_disable(fsg->bulk_in);
+               fsg->bulk_in_enabled = 0;
+       }
+       if (fsg->bulk_out_enabled) {
+               usb_ep_disable(fsg->bulk_out);
+               fsg->bulk_out_enabled = 0;
+       }
+       if (fsg->intr_in_enabled) {
+               usb_ep_disable(fsg->intr_in);
+               fsg->intr_in_enabled = 0;
+       }
+
+       fsg->running = 0;
+       if (altsetting < 0 || rc != 0)
+               return rc;
+
+       DBG(fsg, "set interface %d\n", altsetting);
+
+       /* Enable the endpoints */
+       d = fsg_ep_desc(fsg->gadget,
+                       &fsg_fs_bulk_in_desc, &fsg_hs_bulk_in_desc);
+       if ((rc = enable_endpoint(fsg, fsg->bulk_in, d)) != 0)
+               goto reset;
+       fsg->bulk_in_enabled = 1;
+
+       d = fsg_ep_desc(fsg->gadget,
+                       &fsg_fs_bulk_out_desc, &fsg_hs_bulk_out_desc);
+       if ((rc = enable_endpoint(fsg, fsg->bulk_out, d)) != 0)
+               goto reset;
+       fsg->bulk_out_enabled = 1;
+       fsg->bulk_out_maxpacket = le16_to_cpu(d->wMaxPacketSize);
+       clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
+
+       if (transport_is_cbi()) {
+               d = fsg_ep_desc(fsg->gadget,
+                               &fsg_fs_intr_in_desc, &fsg_hs_intr_in_desc);
+               if ((rc = enable_endpoint(fsg, fsg->intr_in, d)) != 0)
+                       goto reset;
+               fsg->intr_in_enabled = 1;
+       }
+
+       /* Allocate the requests */
+       for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+               struct fsg_buffhd       *bh = &fsg->buffhds[i];
+
+               if ((rc = alloc_request(fsg, fsg->bulk_in, &bh->inreq)) != 0)
+                       goto reset;
+               if ((rc = alloc_request(fsg, fsg->bulk_out, &bh->outreq)) != 0)
+                       goto reset;
+               bh->inreq->buf = bh->outreq->buf = bh->buf;
+               bh->inreq->context = bh->outreq->context = bh;
+               bh->inreq->complete = bulk_in_complete;
+               bh->outreq->complete = bulk_out_complete;
+       }
+       if (transport_is_cbi()) {
+               if ((rc = alloc_request(fsg, fsg->intr_in, &fsg->intreq)) != 0)
+                       goto reset;
+               fsg->intreq->complete = intr_in_complete;
+       }
+
+       fsg->running = 1;
+       for (i = 0; i < fsg->nluns; ++i)
+               fsg->luns[i].unit_attention_data = SS_RESET_OCCURRED;
+       return rc;
+}
+
+
+/*
+ * Change our operational configuration.  This code must agree with the code
+ * that returns config descriptors, and with interface altsetting code.
+ *
+ * It's also responsible for power management interactions.  Some
+ * configurations might not work with our current power sources.
+ * For now we just assume the gadget is always self-powered.
+ */
+static int do_set_config(struct fsg_dev *fsg, u8 new_config)
+{
+       int     rc = 0;
+
+       /* Disable the single interface */
+       if (fsg->config != 0) {
+               DBG(fsg, "reset config\n");
+               fsg->config = 0;
+               rc = do_set_interface(fsg, -1);
+       }
+
+       /* Enable the interface */
+       if (new_config != 0) {
+               fsg->config = new_config;
+               if ((rc = do_set_interface(fsg, 0)) != 0)
+                       fsg->config = 0;        // Reset on errors
+               else {
+                       char *speed;
+
+                       switch (fsg->gadget->speed) {
+                       case USB_SPEED_LOW:     speed = "low";  break;
+                       case USB_SPEED_FULL:    speed = "full"; break;
+                       case USB_SPEED_HIGH:    speed = "high"; break;
+                       default:                speed = "?";    break;
+                       }
+                       INFO(fsg, "%s speed config #%d\n", speed, fsg->config);
+               }
+       }
+       return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static void handle_exception(struct fsg_dev *fsg)
+{
+       siginfo_t               info;
+       int                     sig;
+       int                     i;
+       int                     num_active;
+       struct fsg_buffhd       *bh;
+       enum fsg_state          old_state;
+       u8                      new_config;
+       struct fsg_lun          *curlun;
+       unsigned int            exception_req_tag;
+       int                     rc;
+
+       /* Clear the existing signals.  Anything but SIGUSR1 is converted
+        * into a high-priority EXIT exception. */
+       for (;;) {
+               sig = dequeue_signal_lock(current, &current->blocked, &info);
+               if (!sig)
+                       break;
+               if (sig != SIGUSR1) {
+                       if (fsg->state < FSG_STATE_EXIT)
+                               DBG(fsg, "Main thread exiting on signal\n");
+                       raise_exception(fsg, FSG_STATE_EXIT);
+               }
+       }
+
+       /* Cancel all the pending transfers */
+       if (fsg->intreq_busy)
+               usb_ep_dequeue(fsg->intr_in, fsg->intreq);
+       for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+               bh = &fsg->buffhds[i];
+               if (bh->inreq_busy)
+                       usb_ep_dequeue(fsg->bulk_in, bh->inreq);
+               if (bh->outreq_busy)
+                       usb_ep_dequeue(fsg->bulk_out, bh->outreq);
+       }
+
+       /* Wait until everything is idle */
+       for (;;) {
+               num_active = fsg->intreq_busy;
+               for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+                       bh = &fsg->buffhds[i];
+                       num_active += bh->inreq_busy + bh->outreq_busy;
+               }
+               if (num_active == 0)
+                       break;
+               if (sleep_thread(fsg))
+                       return;
+       }
+
+       /* Clear out the controller's fifos */
+       if (fsg->bulk_in_enabled)
+               usb_ep_fifo_flush(fsg->bulk_in);
+       if (fsg->bulk_out_enabled)
+               usb_ep_fifo_flush(fsg->bulk_out);
+       if (fsg->intr_in_enabled)
+               usb_ep_fifo_flush(fsg->intr_in);
+
+       /* Reset the I/O buffer states and pointers, the SCSI
+        * state, and the exception.  Then invoke the handler. */
+       spin_lock_irq(&fsg->lock);
+
+       for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+               bh = &fsg->buffhds[i];
+               bh->state = BUF_STATE_EMPTY;
+       }
+       fsg->next_buffhd_to_fill = fsg->next_buffhd_to_drain =
+                       &fsg->buffhds[0];
+
+       exception_req_tag = fsg->exception_req_tag;
+       new_config = fsg->new_config;
+       old_state = fsg->state;
+
+       if (old_state == FSG_STATE_ABORT_BULK_OUT)
+               fsg->state = FSG_STATE_STATUS_PHASE;
+       else {
+               for (i = 0; i < fsg->nluns; ++i) {
+                       curlun = &fsg->luns[i];
+                       curlun->prevent_medium_removal = 0;
+                       curlun->sense_data = curlun->unit_attention_data =
+                                       SS_NO_SENSE;
+                       curlun->sense_data_info = 0;
+                       curlun->info_valid = 0;
+               }
+               fsg->state = FSG_STATE_IDLE;
+       }
+       spin_unlock_irq(&fsg->lock);
+
+       /* Carry out any extra actions required for the exception */
+       switch (old_state) {
+       default:
+               break;
+
+       case FSG_STATE_ABORT_BULK_OUT:
+               send_status(fsg);
+               spin_lock_irq(&fsg->lock);
+               if (fsg->state == FSG_STATE_STATUS_PHASE)
+                       fsg->state = FSG_STATE_IDLE;
+               spin_unlock_irq(&fsg->lock);
+               break;
+
+       case FSG_STATE_RESET:
+               /* In case we were forced against our will to halt a
+                * bulk endpoint, clear the halt now.  (The SuperH UDC
+                * requires this.) */
+               if (test_and_clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags))
+                       usb_ep_clear_halt(fsg->bulk_in);
+
+               if (transport_is_bbb()) {
+                       if (fsg->ep0_req_tag == exception_req_tag)
+                               ep0_queue(fsg); // Complete the status stage
+
+               } else if (transport_is_cbi())
+                       send_status(fsg);       // Status by interrupt pipe
+
+               /* Technically this should go here, but it would only be
+                * a waste of time.  Ditto for the INTERFACE_CHANGE and
+                * CONFIG_CHANGE cases. */
+               // for (i = 0; i < fsg->nluns; ++i)
+               //      fsg->luns[i].unit_attention_data = SS_RESET_OCCURRED;
+               break;
+
+       case FSG_STATE_INTERFACE_CHANGE:
+               rc = do_set_interface(fsg, 0);
+               if (fsg->ep0_req_tag != exception_req_tag)
+                       break;
+               if (rc != 0)                    // STALL on errors
+                       fsg_set_halt(fsg, fsg->ep0);
+               else                            // Complete the status stage
+                       ep0_queue(fsg);
+               break;
+
+       case FSG_STATE_CONFIG_CHANGE:
+               rc = do_set_config(fsg, new_config);
+               if (fsg->ep0_req_tag != exception_req_tag)
+                       break;
+               if (rc != 0)                    // STALL on errors
+                       fsg_set_halt(fsg, fsg->ep0);
+               else                            // Complete the status stage
+                       ep0_queue(fsg);
+               break;
+
+       case FSG_STATE_DISCONNECT:
+               for (i = 0; i < fsg->nluns; ++i)
+                       fsg_lun_fsync_sub(fsg->luns + i);
+               do_set_config(fsg, 0);          // Unconfigured state
+               break;
+
+       case FSG_STATE_EXIT:
+       case FSG_STATE_TERMINATED:
+               do_set_config(fsg, 0);                  // Free resources
+               spin_lock_irq(&fsg->lock);
+               fsg->state = FSG_STATE_TERMINATED;      // Stop the thread
+               spin_unlock_irq(&fsg->lock);
+               break;
+       }
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static int fsg_main_thread(void *fsg_)
+{
+       struct fsg_dev          *fsg = fsg_;
+
+       /* Allow the thread to be killed by a signal, but set the signal mask
+        * to block everything but INT, TERM, KILL, and USR1. */
+       allow_signal(SIGINT);
+       allow_signal(SIGTERM);
+       allow_signal(SIGKILL);
+       allow_signal(SIGUSR1);
+
+       /* Allow the thread to be frozen */
+       set_freezable();
+
+       /* Arrange for userspace references to be interpreted as kernel
+        * pointers.  That way we can pass a kernel pointer to a routine
+        * that expects a __user pointer and it will work okay. */
+       set_fs(get_ds());
+
+       /* The main loop */
+       while (fsg->state != FSG_STATE_TERMINATED) {
+               if (exception_in_progress(fsg) || signal_pending(current)) {
+                       handle_exception(fsg);
+                       continue;
+               }
+
+               if (!fsg->running) {
+                       sleep_thread(fsg);
+                       continue;
+               }
+
+               if (get_next_command(fsg))
+                       continue;
+
+               spin_lock_irq(&fsg->lock);
+               if (!exception_in_progress(fsg))
+                       fsg->state = FSG_STATE_DATA_PHASE;
+               spin_unlock_irq(&fsg->lock);
+
+               if (do_scsi_command(fsg) || finish_reply(fsg))
+                       continue;
+
+               spin_lock_irq(&fsg->lock);
+               if (!exception_in_progress(fsg))
+                       fsg->state = FSG_STATE_STATUS_PHASE;
+               spin_unlock_irq(&fsg->lock);
+
+               if (send_status(fsg))
+                       continue;
+
+               spin_lock_irq(&fsg->lock);
+               if (!exception_in_progress(fsg))
+                       fsg->state = FSG_STATE_IDLE;
+               spin_unlock_irq(&fsg->lock);
+               }
+
+       spin_lock_irq(&fsg->lock);
+       fsg->thread_task = NULL;
+       spin_unlock_irq(&fsg->lock);
+
+       /* If we are exiting because of a signal, unregister the
+        * gadget driver. */
+       if (test_and_clear_bit(REGISTERED, &fsg->atomic_bitflags))
+               usb_gadget_unregister_driver(&fsg_driver);
+
+       /* Let the unbind and cleanup routines know the thread has exited */
+       complete_and_exit(&fsg->thread_notifier, 0);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+
+/* The write permissions and store_xxx pointers are set in fsg_bind() */
+static DEVICE_ATTR(ro, 0444, fsg_show_ro, NULL);
+static DEVICE_ATTR(file, 0444, fsg_show_file, NULL);
+
+
+/*-------------------------------------------------------------------------*/
+
+static void fsg_release(struct kref *ref)
+{
+       struct fsg_dev  *fsg = container_of(ref, struct fsg_dev, ref);
+
+       kfree(fsg->luns);
+       kfree(fsg);
+}
+
+static void lun_release(struct device *dev)
+{
+       struct rw_semaphore     *filesem = dev_get_drvdata(dev);
+       struct fsg_dev          *fsg =
+               container_of(filesem, struct fsg_dev, filesem);
+
+       kref_put(&fsg->ref, fsg_release);
+}
+
+static void /* __init_or_exit */ fsg_unbind(struct usb_gadget *gadget)
+{
+       struct fsg_dev          *fsg = get_gadget_data(gadget);
+       int                     i;
+       struct fsg_lun          *curlun;
+       struct usb_request      *req = fsg->ep0req;
+
+       DBG(fsg, "unbind\n");
+       clear_bit(REGISTERED, &fsg->atomic_bitflags);
+
+       /* Unregister the sysfs attribute files and the LUNs */
+       for (i = 0; i < fsg->nluns; ++i) {
+               curlun = &fsg->luns[i];
+               if (curlun->registered) {
+                       device_remove_file(&curlun->dev, &dev_attr_ro);
+                       device_remove_file(&curlun->dev, &dev_attr_file);
+                       fsg_lun_close(curlun);
+                       device_unregister(&curlun->dev);
+                       curlun->registered = 0;
+               }
+       }
+
+       /* If the thread isn't already dead, tell it to exit now */
+       if (fsg->state != FSG_STATE_TERMINATED) {
+               raise_exception(fsg, FSG_STATE_EXIT);
+               wait_for_completion(&fsg->thread_notifier);
+
+               /* The cleanup routine waits for this completion also */
+               complete(&fsg->thread_notifier);
+       }
+
+       /* Free the data buffers */
+       for (i = 0; i < FSG_NUM_BUFFERS; ++i)
+               kfree(fsg->buffhds[i].buf);
+
+       /* Free the request and buffer for endpoint 0 */
+       if (req) {
+               kfree(req->buf);
+               usb_ep_free_request(fsg->ep0, req);
+       }
+
+       set_gadget_data(gadget, NULL);
+}
+
+
+static int __init check_parameters(struct fsg_dev *fsg)
+{
+       int     prot;
+       int     gcnum;
+
+       /* Store the default values */
+       mod_data.transport_type = USB_PR_BULK;
+       mod_data.transport_name = "Bulk-only";
+       mod_data.protocol_type = USB_SC_SCSI;
+       mod_data.protocol_name = "Transparent SCSI";
+
+       /* Some peripheral controllers are known not to be able to
+        * halt bulk endpoints correctly.  If one of them is present,
+        * disable stalls.
+        */
+       if (gadget_is_sh(fsg->gadget) || gadget_is_at91(fsg->gadget))
+               mod_data.can_stall = 0;
+
+       if (mod_data.release == 0xffff) {       // Parameter wasn't set
+               /* The sa1100 controller is not supported */
+               if (gadget_is_sa1100(fsg->gadget))
+                       gcnum = -1;
+               else
+                       gcnum = usb_gadget_controller_number(fsg->gadget);
+               if (gcnum >= 0)
+                       mod_data.release = 0x0300 + gcnum;
+               else {
+                       WARNING(fsg, "controller '%s' not recognized\n",
+                               fsg->gadget->name);
+                       mod_data.release = 0x0399;
+               }
+       }
+
+       prot = simple_strtol(mod_data.protocol_parm, NULL, 0);
+
+#ifdef CONFIG_USB_FILE_STORAGE_TEST
+       if (strnicmp(mod_data.transport_parm, "BBB", 10) == 0) {
+               ;               // Use default setting
+       } else if (strnicmp(mod_data.transport_parm, "CB", 10) == 0) {
+               mod_data.transport_type = USB_PR_CB;
+               mod_data.transport_name = "Control-Bulk";
+       } else if (strnicmp(mod_data.transport_parm, "CBI", 10) == 0) {
+               mod_data.transport_type = USB_PR_CBI;
+               mod_data.transport_name = "Control-Bulk-Interrupt";
+       } else {
+               ERROR(fsg, "invalid transport: %s\n", mod_data.transport_parm);
+               return -EINVAL;
+       }
+
+       if (strnicmp(mod_data.protocol_parm, "SCSI", 10) == 0 ||
+                       prot == USB_SC_SCSI) {
+               ;               // Use default setting
+       } else if (strnicmp(mod_data.protocol_parm, "RBC", 10) == 0 ||
+                       prot == USB_SC_RBC) {
+               mod_data.protocol_type = USB_SC_RBC;
+               mod_data.protocol_name = "RBC";
+       } else if (strnicmp(mod_data.protocol_parm, "8020", 4) == 0 ||
+                       strnicmp(mod_data.protocol_parm, "ATAPI", 10) == 0 ||
+                       prot == USB_SC_8020) {
+               mod_data.protocol_type = USB_SC_8020;
+               mod_data.protocol_name = "8020i (ATAPI)";
+       } else if (strnicmp(mod_data.protocol_parm, "QIC", 3) == 0 ||
+                       prot == USB_SC_QIC) {
+               mod_data.protocol_type = USB_SC_QIC;
+               mod_data.protocol_name = "QIC-157";
+       } else if (strnicmp(mod_data.protocol_parm, "UFI", 10) == 0 ||
+                       prot == USB_SC_UFI) {
+               mod_data.protocol_type = USB_SC_UFI;
+               mod_data.protocol_name = "UFI";
+       } else if (strnicmp(mod_data.protocol_parm, "8070", 4) == 0 ||
+                       prot == USB_SC_8070) {
+               mod_data.protocol_type = USB_SC_8070;
+               mod_data.protocol_name = "8070i";
+       } else {
+               ERROR(fsg, "invalid protocol: %s\n", mod_data.protocol_parm);
+               return -EINVAL;
+       }
+
+       mod_data.buflen &= PAGE_CACHE_MASK;
+       if (mod_data.buflen <= 0) {
+               ERROR(fsg, "invalid buflen\n");
+               return -ETOOSMALL;
+       }
+#endif /* CONFIG_USB_FILE_STORAGE_TEST */
+
+       return 0;
+}
+
+
+static int __init fsg_bind(struct usb_gadget *gadget)
+{
+       struct fsg_dev          *fsg = the_fsg;
+       int                     rc;
+       int                     i;
+       struct fsg_lun          *curlun;
+       struct usb_ep           *ep;
+       struct usb_request      *req;
+       char                    *pathbuf, *p;
+
+       fsg->gadget = gadget;
+       set_gadget_data(gadget, fsg);
+       fsg->ep0 = gadget->ep0;
+       fsg->ep0->driver_data = fsg;
+
+       if ((rc = check_parameters(fsg)) != 0)
+               goto out;
+
+       if (mod_data.removable) {       // Enable the store_xxx attributes
+               dev_attr_file.attr.mode = 0644;
+               dev_attr_file.store = fsg_store_file;
+               if (!mod_data.cdrom) {
+                       dev_attr_ro.attr.mode = 0644;
+                       dev_attr_ro.store = fsg_store_ro;
+               }
+       }
+
+       /* Find out how many LUNs there should be */
+       i = mod_data.nluns;
+       if (i == 0)
+               i = max(mod_data.num_filenames, 1u);
+       if (i > FSG_MAX_LUNS) {
+               ERROR(fsg, "invalid number of LUNs: %d\n", i);
+               rc = -EINVAL;
+               goto out;
+       }
+
+       /* Create the LUNs, open their backing files, and register the
+        * LUN devices in sysfs. */
+       fsg->luns = kzalloc(i * sizeof(struct fsg_lun), GFP_KERNEL);
+       if (!fsg->luns) {
+               rc = -ENOMEM;
+               goto out;
+       }
+       fsg->nluns = i;
+
+       for (i = 0; i < fsg->nluns; ++i) {
+               curlun = &fsg->luns[i];
+               curlun->cdrom = !!mod_data.cdrom;
+               curlun->ro = mod_data.cdrom || mod_data.ro[i];
+               curlun->initially_ro = curlun->ro;
+               curlun->removable = mod_data.removable;
+               curlun->dev.release = lun_release;
+               curlun->dev.parent = &gadget->dev;
+               curlun->dev.driver = &fsg_driver.driver;
+               dev_set_drvdata(&curlun->dev, &fsg->filesem);
+               dev_set_name(&curlun->dev,"%s-lun%d",
+                            dev_name(&gadget->dev), i);
+
+               if ((rc = device_register(&curlun->dev)) != 0) {
+                       INFO(fsg, "failed to register LUN%d: %d\n", i, rc);
+                       goto out;
+               }
+               if ((rc = device_create_file(&curlun->dev,
+                                       &dev_attr_ro)) != 0 ||
+                               (rc = device_create_file(&curlun->dev,
+                                       &dev_attr_file)) != 0) {
+                       device_unregister(&curlun->dev);
+                       goto out;
+               }
+               curlun->registered = 1;
+               kref_get(&fsg->ref);
+
+               if (mod_data.file[i] && *mod_data.file[i]) {
+                       if ((rc = fsg_lun_open(curlun,
+                                       mod_data.file[i])) != 0)
+                               goto out;
+               } else if (!mod_data.removable) {
+                       ERROR(fsg, "no file given for LUN%d\n", i);
+                       rc = -EINVAL;
+                       goto out;
+               }
+       }
+
+       /* Find all the endpoints we will use */
+       usb_ep_autoconfig_reset(gadget);
+       ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_in_desc);
+       if (!ep)
+               goto autoconf_fail;
+       ep->driver_data = fsg;          // claim the endpoint
+       fsg->bulk_in = ep;
+
+       ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_out_desc);
+       if (!ep)
+               goto autoconf_fail;
+       ep->driver_data = fsg;          // claim the endpoint
+       fsg->bulk_out = ep;
+
+       if (transport_is_cbi()) {
+               ep = usb_ep_autoconfig(gadget, &fsg_fs_intr_in_desc);
+               if (!ep)
+                       goto autoconf_fail;
+               ep->driver_data = fsg;          // claim the endpoint
+               fsg->intr_in = ep;
+       }
+
+       /* Fix up the descriptors */
+       device_desc.bMaxPacketSize0 = fsg->ep0->maxpacket;
+       device_desc.idVendor = cpu_to_le16(mod_data.vendor);
+       device_desc.idProduct = cpu_to_le16(mod_data.product);
+       device_desc.bcdDevice = cpu_to_le16(mod_data.release);
+
+       i = (transport_is_cbi() ? 3 : 2);       // Number of endpoints
+       fsg_intf_desc.bNumEndpoints = i;
+       fsg_intf_desc.bInterfaceSubClass = mod_data.protocol_type;
+       fsg_intf_desc.bInterfaceProtocol = mod_data.transport_type;
+       fsg_fs_function[i + FSG_FS_FUNCTION_PRE_EP_ENTRIES] = NULL;
+
+       if (gadget_is_dualspeed(gadget)) {
+               fsg_hs_function[i + FSG_HS_FUNCTION_PRE_EP_ENTRIES] = NULL;
+
+               /* Assume ep0 uses the same maxpacket value for both speeds */
+               dev_qualifier.bMaxPacketSize0 = fsg->ep0->maxpacket;
+
+               /* Assume endpoint addresses are the same for both speeds */
+               fsg_hs_bulk_in_desc.bEndpointAddress =
+                       fsg_fs_bulk_in_desc.bEndpointAddress;
+               fsg_hs_bulk_out_desc.bEndpointAddress =
+                       fsg_fs_bulk_out_desc.bEndpointAddress;
+               fsg_hs_intr_in_desc.bEndpointAddress =
+                       fsg_fs_intr_in_desc.bEndpointAddress;
+       }
+
+       if (gadget_is_otg(gadget))
+               fsg_otg_desc.bmAttributes |= USB_OTG_HNP;
+
+       rc = -ENOMEM;
+
+       /* Allocate the request and buffer for endpoint 0 */
+       fsg->ep0req = req = usb_ep_alloc_request(fsg->ep0, GFP_KERNEL);
+       if (!req)
+               goto out;
+       req->buf = kmalloc(EP0_BUFSIZE, GFP_KERNEL);
+       if (!req->buf)
+               goto out;
+       req->complete = ep0_complete;
+
+       /* Allocate the data buffers */
+       for (i = 0; i < FSG_NUM_BUFFERS; ++i) {
+               struct fsg_buffhd       *bh = &fsg->buffhds[i];
+
+               /* Allocate for the bulk-in endpoint.  We assume that
+                * the buffer will also work with the bulk-out (and
+                * interrupt-in) endpoint. */
+               bh->buf = kmalloc(mod_data.buflen, GFP_KERNEL);
+               if (!bh->buf)
+                       goto out;
+               bh->next = bh + 1;
+       }
+       fsg->buffhds[FSG_NUM_BUFFERS - 1].next = &fsg->buffhds[0];
+
+       /* This should reflect the actual gadget power source */
+       usb_gadget_set_selfpowered(gadget);
+
+       snprintf(fsg_string_manufacturer, sizeof fsg_string_manufacturer,
+                       "%s %s with %s",
+                       init_utsname()->sysname, init_utsname()->release,
+                       gadget->name);
+
+       /* On a real device, serial[] would be loaded from permanent
+        * storage.  We just encode it from the driver version string. */
+       for (i = 0; i < sizeof fsg_string_serial - 2; i += 2) {
+               unsigned char           c = DRIVER_VERSION[i / 2];
+
+               if (!c)
+                       break;
+               sprintf(&fsg_string_serial[i], "%02X", c);
+       }
+
+       fsg->thread_task = kthread_create(fsg_main_thread, fsg,
+                       "file-storage-gadget");
+       if (IS_ERR(fsg->thread_task)) {
+               rc = PTR_ERR(fsg->thread_task);
+               goto out;
+       }
+
+       INFO(fsg, DRIVER_DESC ", version: " DRIVER_VERSION "\n");
+       INFO(fsg, "Number of LUNs=%d\n", fsg->nluns);
+
+       pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
+       for (i = 0; i < fsg->nluns; ++i) {
+               curlun = &fsg->luns[i];
+               if (fsg_lun_is_open(curlun)) {
+                       p = NULL;
+                       if (pathbuf) {
+                               p = d_path(&curlun->filp->f_path,
+                                          pathbuf, PATH_MAX);
+                               if (IS_ERR(p))
+                                       p = NULL;
+                       }
+                       LINFO(curlun, "ro=%d, file: %s\n",
+                                       curlun->ro, (p ? p : "(error)"));
+               }
+       }
+       kfree(pathbuf);
+
+       DBG(fsg, "transport=%s (x%02x)\n",
+                       mod_data.transport_name, mod_data.transport_type);
+       DBG(fsg, "protocol=%s (x%02x)\n",
+                       mod_data.protocol_name, mod_data.protocol_type);
+       DBG(fsg, "VendorID=x%04x, ProductID=x%04x, Release=x%04x\n",
+                       mod_data.vendor, mod_data.product, mod_data.release);
+       DBG(fsg, "removable=%d, stall=%d, cdrom=%d, buflen=%u\n",
+                       mod_data.removable, mod_data.can_stall,
+                       mod_data.cdrom, mod_data.buflen);
+       DBG(fsg, "I/O thread pid: %d\n", task_pid_nr(fsg->thread_task));
+
+       set_bit(REGISTERED, &fsg->atomic_bitflags);
+
+       /* Tell the thread to start working */
+       wake_up_process(fsg->thread_task);
+       return 0;
+
+autoconf_fail:
+       ERROR(fsg, "unable to autoconfigure all endpoints\n");
+       rc = -ENOTSUPP;
+
+out:
+       fsg->state = FSG_STATE_TERMINATED;      // The thread is dead
+       fsg_unbind(gadget);
+       complete(&fsg->thread_notifier);
+       return rc;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static void fsg_suspend(struct usb_gadget *gadget)
+{
+       struct fsg_dev          *fsg = get_gadget_data(gadget);
+
+       DBG(fsg, "suspend\n");
+       set_bit(SUSPENDED, &fsg->atomic_bitflags);
+}
+
+static void fsg_resume(struct usb_gadget *gadget)
+{
+       struct fsg_dev          *fsg = get_gadget_data(gadget);
+
+       DBG(fsg, "resume\n");
+       clear_bit(SUSPENDED, &fsg->atomic_bitflags);
+}
+
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_gadget_driver                fsg_driver = {
+#ifdef CONFIG_USB_GADGET_DUALSPEED
+       .speed          = USB_SPEED_HIGH,
+#else
+       .speed          = USB_SPEED_FULL,
+#endif
+       .function       = (char *) fsg_string_product,
+       .bind           = fsg_bind,
+       .unbind         = fsg_unbind,
+       .disconnect     = fsg_disconnect,
+       .setup          = fsg_setup,
+       .suspend        = fsg_suspend,
+       .resume         = fsg_resume,
+
+       .driver         = {
+               .name           = DRIVER_NAME,
+               .owner          = THIS_MODULE,
+               // .release = ...
+               // .suspend = ...
+               // .resume = ...
+       },
+};
+
+
+static int __init fsg_alloc(void)
+{
+       struct fsg_dev          *fsg;
+
+       fsg = kzalloc(sizeof *fsg, GFP_KERNEL);
+       if (!fsg)
+               return -ENOMEM;
+       spin_lock_init(&fsg->lock);
+       init_rwsem(&fsg->filesem);
+       kref_init(&fsg->ref);
+       init_completion(&fsg->thread_notifier);
+
+       the_fsg = fsg;
+       return 0;
+}
+
+
+static int __init fsg_init(void)
+{
+       int             rc;
+       struct fsg_dev  *fsg;
+
+       if ((rc = fsg_alloc()) != 0)
+               return rc;
+       fsg = the_fsg;
+       if ((rc = usb_gadget_register_driver(&fsg_driver)) != 0)
+               kref_put(&fsg->ref, fsg_release);
+       return rc;
+}
+module_init(fsg_init);
+
+
+static void __exit fsg_cleanup(void)
+{
+       struct fsg_dev  *fsg = the_fsg;
+
+       /* Unregister the driver iff the thread hasn't already done so */
+       if (test_and_clear_bit(REGISTERED, &fsg->atomic_bitflags))
+               usb_gadget_unregister_driver(&fsg_driver);
+
+       /* Wait for the thread to finish up */
+       wait_for_completion(&fsg->thread_notifier);
+
+       kref_put(&fsg->ref, fsg_release);
+}
+module_exit(fsg_cleanup);