[mirror_ubuntu-zesty-kernel.git] / drivers / usb / storage / uas.c

/*
 * USB Attached SCSI
 * Note that this is not the same as the USB Mass Storage driver
 *
 * Copyright Hans de Goede <hdegoede@redhat.com> for Red Hat, Inc. 2013 - 2014
 * Copyright Matthew Wilcox for Intel Corp, 2010
 * Copyright Sarah Sharp for Intel Corp, 2010
 *
 * Distributed under the terms of the GNU GPL, version two.
 */

#include <linux/blkdev.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb_usual.h>
#include <linux/usb/hcd.h>
#include <linux/usb/storage.h>
#include <linux/usb/uas.h>

#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dbg.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_tcq.h>

#include "uas-detect.h"
#include "scsiglue.h"

#define MAX_CMNDS 256

/*
 * The r00-r01c specs define this version of the SENSE IU data structure.
 * It's still in use by several different firmware releases.
 */
struct sense_iu_old {
        __u8 iu_id;
        __u8 rsvd1;
        __be16 tag;
        __be16 len;
        __u8 status;
        __u8 service_response;
        __u8 sense[SCSI_SENSE_BUFFERSIZE];
};

struct uas_dev_info {
        struct usb_interface *intf;
        struct usb_device *udev;
        struct usb_anchor cmd_urbs;
        struct usb_anchor sense_urbs;
        struct usb_anchor data_urbs;
        unsigned long flags;
        int qdepth, resetting;
        unsigned cmd_pipe, status_pipe, data_in_pipe, data_out_pipe;
        unsigned use_streams:1;
        unsigned uas_sense_old:1;
        unsigned shutdown:1;
        struct scsi_cmnd *cmnd[MAX_CMNDS];
        spinlock_t lock;
        struct work_struct work;
};

enum {
        SUBMIT_STATUS_URB       = (1 << 1),
        ALLOC_DATA_IN_URB       = (1 << 2),
        SUBMIT_DATA_IN_URB      = (1 << 3),
        ALLOC_DATA_OUT_URB      = (1 << 4),
        SUBMIT_DATA_OUT_URB     = (1 << 5),
        ALLOC_CMD_URB           = (1 << 6),
        SUBMIT_CMD_URB          = (1 << 7),
        COMMAND_INFLIGHT        = (1 << 8),
        DATA_IN_URB_INFLIGHT    = (1 << 9),
        DATA_OUT_URB_INFLIGHT   = (1 << 10),
        COMMAND_COMPLETED       = (1 << 11),
        COMMAND_ABORTED         = (1 << 12),
        IS_IN_WORK_LIST         = (1 << 13),
};

/* Overrides scsi_pointer */
struct uas_cmd_info {
        unsigned int state;
        unsigned int stream;
        struct urb *cmd_urb;
        struct urb *data_in_urb;
        struct urb *data_out_urb;
};

/* I hate forward declarations, but I actually have a loop */
static int uas_submit_urbs(struct scsi_cmnd *cmnd,
                                struct uas_dev_info *devinfo, gfp_t gfp);
static void uas_do_work(struct work_struct *work);
static int uas_try_complete(struct scsi_cmnd *cmnd, const char *caller);
static void uas_free_streams(struct uas_dev_info *devinfo);
static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *caller);

static void uas_do_work(struct work_struct *work)
{
        struct uas_dev_info *devinfo =
                container_of(work, struct uas_dev_info, work);
        struct uas_cmd_info *cmdinfo;
        struct scsi_cmnd *cmnd;
        unsigned long flags;
        int i, err;

        spin_lock_irqsave(&devinfo->lock, flags);

        if (devinfo->resetting)
                goto out;

        for (i = 0; i < devinfo->qdepth; i++) {
                if (!devinfo->cmnd[i])
                        continue;

                cmnd = devinfo->cmnd[i];
                cmdinfo = (void *)&cmnd->SCp;

                if (!(cmdinfo->state & IS_IN_WORK_LIST))
                        continue;

                err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_ATOMIC);
                if (!err)
                        cmdinfo->state &= ~IS_IN_WORK_LIST;
                else
                        schedule_work(&devinfo->work);
        }
out:
        spin_unlock_irqrestore(&devinfo->lock, flags);
}

static void uas_add_work(struct uas_cmd_info *cmdinfo)
{
        struct scsi_pointer *scp = (void *)cmdinfo;
        struct scsi_cmnd *cmnd = container_of(scp, struct scsi_cmnd, SCp);
        struct uas_dev_info *devinfo = cmnd->device->hostdata;

        lockdep_assert_held(&devinfo->lock);
        cmdinfo->state |= IS_IN_WORK_LIST;
        schedule_work(&devinfo->work);
}

static void uas_zap_pending(struct uas_dev_info *devinfo, int result)
{
        struct uas_cmd_info *cmdinfo;
        struct scsi_cmnd *cmnd;
        unsigned long flags;
        int i, err;

        spin_lock_irqsave(&devinfo->lock, flags);
        for (i = 0; i < devinfo->qdepth; i++) {
                if (!devinfo->cmnd[i])
                        continue;

                cmnd = devinfo->cmnd[i];
                cmdinfo = (void *)&cmnd->SCp;
                uas_log_cmd_state(cmnd, __func__);
                /* Sense urbs were killed, clear COMMAND_INFLIGHT manually */
                cmdinfo->state &= ~COMMAND_INFLIGHT;
                cmnd->result = result << 16;
                err = uas_try_complete(cmnd, __func__);
                WARN_ON(err != 0);
        }
        spin_unlock_irqrestore(&devinfo->lock, flags);
}

static void uas_sense(struct urb *urb, struct scsi_cmnd *cmnd)
{
        struct sense_iu *sense_iu = urb->transfer_buffer;
        struct scsi_device *sdev = cmnd->device;

        if (urb->actual_length > 16) {
                unsigned len = be16_to_cpup(&sense_iu->len);
                if (len + 16 != urb->actual_length) {
                        int newlen = min(len + 16, urb->actual_length) - 16;
                        if (newlen < 0)
                                newlen = 0;
                        sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
                                "disagrees with IU sense data length %d, "
                                "using %d bytes of sense data\n", __func__,
                                        urb->actual_length, len, newlen);
                        len = newlen;
                }
                memcpy(cmnd->sense_buffer, sense_iu->sense, len);
        }

        cmnd->result = sense_iu->status;
}

static void uas_sense_old(struct urb *urb, struct scsi_cmnd *cmnd)
{
        struct sense_iu_old *sense_iu = urb->transfer_buffer;
        struct scsi_device *sdev = cmnd->device;

        if (urb->actual_length > 8) {
                unsigned len = be16_to_cpup(&sense_iu->len) - 2;
                if (len + 8 != urb->actual_length) {
                        int newlen = min(len + 8, urb->actual_length) - 8;
                        if (newlen < 0)
                                newlen = 0;
                        sdev_printk(KERN_INFO, sdev, "%s: urb length %d "
                                "disagrees with IU sense data length %d, "
                                "using %d bytes of sense data\n", __func__,
                                        urb->actual_length, len, newlen);
                        len = newlen;
                }
                memcpy(cmnd->sense_buffer, sense_iu->sense, len);
        }

        cmnd->result = sense_iu->status;
}

/*
 * scsi-tags go from 0 - (nr_tags - 1), uas tags need to match stream-ids,
 * which go from 1 - nr_streams. And we use 1 for untagged commands.
 */
static int uas_get_tag(struct scsi_cmnd *cmnd)
{
        int tag;

        if (blk_rq_tagged(cmnd->request))
                tag = cmnd->request->tag + 2;
        else
                tag = 1;

        return tag;
}

static void uas_log_cmd_state(struct scsi_cmnd *cmnd, const char *caller)
{
        struct uas_cmd_info *ci = (void *)&cmnd->SCp;

        scmd_printk(KERN_INFO, cmnd,
                    "%s %p tag %d, inflight:%s%s%s%s%s%s%s%s%s%s%s%s%s\n",
                    caller, cmnd, uas_get_tag(cmnd),
                    (ci->state & SUBMIT_STATUS_URB)     ? " s-st"  : "",
                    (ci->state & ALLOC_DATA_IN_URB)     ? " a-in"  : "",
                    (ci->state & SUBMIT_DATA_IN_URB)    ? " s-in"  : "",
                    (ci->state & ALLOC_DATA_OUT_URB)    ? " a-out" : "",
                    (ci->state & SUBMIT_DATA_OUT_URB)   ? " s-out" : "",
                    (ci->state & ALLOC_CMD_URB)         ? " a-cmd" : "",
                    (ci->state & SUBMIT_CMD_URB)        ? " s-cmd" : "",
                    (ci->state & COMMAND_INFLIGHT)      ? " CMD"   : "",
                    (ci->state & DATA_IN_URB_INFLIGHT)  ? " IN"    : "",
                    (ci->state & DATA_OUT_URB_INFLIGHT) ? " OUT"   : "",
                    (ci->state & COMMAND_COMPLETED)     ? " done"  : "",
                    (ci->state & COMMAND_ABORTED)       ? " abort" : "",
                    (ci->state & IS_IN_WORK_LIST)       ? " work"  : "");
}

static void uas_free_unsubmitted_urbs(struct scsi_cmnd *cmnd)
{
        struct uas_cmd_info *cmdinfo;

        if (!cmnd)
                return;

        cmdinfo = (void *)&cmnd->SCp;

        if (cmdinfo->state & SUBMIT_CMD_URB)
                usb_free_urb(cmdinfo->cmd_urb);

        /* data urbs may have never gotten their submit flag set */
        if (!(cmdinfo->state & DATA_IN_URB_INFLIGHT))
                usb_free_urb(cmdinfo->data_in_urb);
        if (!(cmdinfo->state & DATA_OUT_URB_INFLIGHT))
                usb_free_urb(cmdinfo->data_out_urb);
}

static int uas_try_complete(struct scsi_cmnd *cmnd, const char *caller)
{
        struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
        struct uas_dev_info *devinfo = (void *)cmnd->device->hostdata;

        lockdep_assert_held(&devinfo->lock);
        if (cmdinfo->state & (COMMAND_INFLIGHT |
                              DATA_IN_URB_INFLIGHT |
                              DATA_OUT_URB_INFLIGHT |
                              COMMAND_ABORTED))
                return -EBUSY;
        WARN_ON_ONCE(cmdinfo->state & COMMAND_COMPLETED);
        cmdinfo->state |= COMMAND_COMPLETED;
        devinfo->cmnd[uas_get_tag(cmnd) - 1] = NULL;
        uas_free_unsubmitted_urbs(cmnd);
        cmnd->scsi_done(cmnd);
        return 0;
}

static void uas_xfer_data(struct urb *urb, struct scsi_cmnd *cmnd,
                          unsigned direction)
{
        struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
        int err;

        cmdinfo->state |= direction | SUBMIT_STATUS_URB;
        err = uas_submit_urbs(cmnd, cmnd->device->hostdata, GFP_ATOMIC);
        if (err) {
                uas_add_work(cmdinfo);
        }
}

static void uas_stat_cmplt(struct urb *urb)
{
        struct iu *iu = urb->transfer_buffer;
        struct Scsi_Host *shost = urb->context;
        struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
        struct urb *data_in_urb = NULL;
        struct urb *data_out_urb = NULL;
        struct scsi_cmnd *cmnd;
        struct uas_cmd_info *cmdinfo;
        unsigned long flags;
        unsigned int idx;

        spin_lock_irqsave(&devinfo->lock, flags);

        if (devinfo->resetting)
                goto out;

        if (urb->status) {
                if (urb->status == -ENOENT) {
                        dev_err(&urb->dev->dev, "stat urb: killed, stream %d\n",
                                urb->stream_id);
                } else {
                        dev_err(&urb->dev->dev, "stat urb: status %d\n",
                                urb->status);
                }
                goto out;
        }

        idx = be16_to_cpup(&iu->tag) - 1;
        if (idx >= MAX_CMNDS || !devinfo->cmnd[idx]) {
                dev_err(&urb->dev->dev,
                        "stat urb: no pending cmd for tag %d\n", idx + 1);
                goto out;
        }

        cmnd = devinfo->cmnd[idx];
        cmdinfo = (void *)&cmnd->SCp;

        if (!(cmdinfo->state & COMMAND_INFLIGHT)) {
                scmd_printk(KERN_ERR, cmnd, "unexpected status cmplt\n");
                goto out;
        }

        switch (iu->iu_id) {
        case IU_ID_STATUS:
                if (urb->actual_length < 16)
                        devinfo->uas_sense_old = 1;
                if (devinfo->uas_sense_old)
                        uas_sense_old(urb, cmnd);
                else
                        uas_sense(urb, cmnd);
                if (cmnd->result != 0) {
                        /* cancel data transfers on error */
                        data_in_urb = usb_get_urb(cmdinfo->data_in_urb);
                        data_out_urb = usb_get_urb(cmdinfo->data_out_urb);
                }
                cmdinfo->state &= ~COMMAND_INFLIGHT;
                uas_try_complete(cmnd, __func__);
                break;
        case IU_ID_READ_READY:
                if (!cmdinfo->data_in_urb ||
                                (cmdinfo->state & DATA_IN_URB_INFLIGHT)) {
                        scmd_printk(KERN_ERR, cmnd, "unexpected read rdy\n");
                        break;
                }
                uas_xfer_data(urb, cmnd, SUBMIT_DATA_IN_URB);
                break;
        case IU_ID_WRITE_READY:
                if (!cmdinfo->data_out_urb ||
                                (cmdinfo->state & DATA_OUT_URB_INFLIGHT)) {
                        scmd_printk(KERN_ERR, cmnd, "unexpected write rdy\n");
                        break;
                }
                uas_xfer_data(urb, cmnd, SUBMIT_DATA_OUT_URB);
                break;
        default:
                scmd_printk(KERN_ERR, cmnd,
                        "Bogus IU (%d) received on status pipe\n", iu->iu_id);
        }
out:
        usb_free_urb(urb);
        spin_unlock_irqrestore(&devinfo->lock, flags);

        /* Unlinking of data urbs must be done without holding the lock */
        if (data_in_urb) {
                usb_unlink_urb(data_in_urb);
                usb_put_urb(data_in_urb);
        }
        if (data_out_urb) {
                usb_unlink_urb(data_out_urb);
                usb_put_urb(data_out_urb);
        }
}

static void uas_data_cmplt(struct urb *urb)
{
        struct scsi_cmnd *cmnd = urb->context;
        struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
        struct uas_dev_info *devinfo = (void *)cmnd->device->hostdata;
        struct scsi_data_buffer *sdb = NULL;
        unsigned long flags;

        spin_lock_irqsave(&devinfo->lock, flags);

        if (cmdinfo->data_in_urb == urb) {
                sdb = scsi_in(cmnd);
                cmdinfo->state &= ~DATA_IN_URB_INFLIGHT;
                cmdinfo->data_in_urb = NULL;
        } else if (cmdinfo->data_out_urb == urb) {
                sdb = scsi_out(cmnd);
                cmdinfo->state &= ~DATA_OUT_URB_INFLIGHT;
                cmdinfo->data_out_urb = NULL;
        }
        if (sdb == NULL) {
                WARN_ON_ONCE(1);
                goto out;
        }

        if (devinfo->resetting)
                goto out;

        /* Data urbs should not complete before the cmd urb is submitted */
        if (cmdinfo->state & SUBMIT_CMD_URB) {
                scmd_printk(KERN_ERR, cmnd, "unexpected data cmplt\n");
                goto out;
        }

        if (urb->status) {
                if (urb->status != -ECONNRESET) {
                        uas_log_cmd_state(cmnd, __func__);
                        scmd_printk(KERN_ERR, cmnd,
                                "data cmplt err %d stream %d\n",
                                urb->status, urb->stream_id);
                }
                /* error: no data transfered */
                sdb->resid = sdb->length;
        } else {
                sdb->resid = sdb->length - urb->actual_length;
        }
        uas_try_complete(cmnd, __func__);
out:
        usb_free_urb(urb);
        spin_unlock_irqrestore(&devinfo->lock, flags);
}

static void uas_cmd_cmplt(struct urb *urb)
{
        if (urb->status)
                dev_err(&urb->dev->dev, "cmd cmplt err %d\n", urb->status);

        usb_free_urb(urb);
}

static struct urb *uas_alloc_data_urb(struct uas_dev_info *devinfo, gfp_t gfp,
                                      unsigned int pipe, u16 stream_id,
                                      struct scsi_cmnd *cmnd,
                                      enum dma_data_direction dir)
{
        struct usb_device *udev = devinfo->udev;
        struct urb *urb = usb_alloc_urb(0, gfp);
        struct scsi_data_buffer *sdb = (dir == DMA_FROM_DEVICE)
                ? scsi_in(cmnd) : scsi_out(cmnd);

        if (!urb)
                goto out;
        usb_fill_bulk_urb(urb, udev, pipe, NULL, sdb->length,
                          uas_data_cmplt, cmnd);
        urb->stream_id = stream_id;
        urb->num_sgs = udev->bus->sg_tablesize ? sdb->table.nents : 0;
        urb->sg = sdb->table.sgl;
 out:
        return urb;
}

static struct urb *uas_alloc_sense_urb(struct uas_dev_info *devinfo, gfp_t gfp,
                                       struct Scsi_Host *shost, u16 stream_id)
{
        struct usb_device *udev = devinfo->udev;
        struct urb *urb = usb_alloc_urb(0, gfp);
        struct sense_iu *iu;

        if (!urb)
                goto out;

        iu = kzalloc(sizeof(*iu), gfp);
        if (!iu)
                goto free;

        usb_fill_bulk_urb(urb, udev, devinfo->status_pipe, iu, sizeof(*iu),
                                                uas_stat_cmplt, shost);
        urb->stream_id = stream_id;
        urb->transfer_flags |= URB_FREE_BUFFER;
 out:
        return urb;
 free:
        usb_free_urb(urb);
        return NULL;
}

static struct urb *uas_alloc_cmd_urb(struct uas_dev_info *devinfo, gfp_t gfp,
                                        struct scsi_cmnd *cmnd)
{
        struct usb_device *udev = devinfo->udev;
        struct scsi_device *sdev = cmnd->device;
        struct urb *urb = usb_alloc_urb(0, gfp);
        struct command_iu *iu;
        int len;

        if (!urb)
                goto out;

        len = cmnd->cmd_len - 16;
        if (len < 0)
                len = 0;
        len = ALIGN(len, 4);
        iu = kzalloc(sizeof(*iu) + len, gfp);
        if (!iu)
                goto free;

        iu->iu_id = IU_ID_COMMAND;
        iu->tag = cpu_to_be16(uas_get_tag(cmnd));
        iu->prio_attr = UAS_SIMPLE_TAG;
        iu->len = len;
        int_to_scsilun(sdev->lun, &iu->lun);
        memcpy(iu->cdb, cmnd->cmnd, cmnd->cmd_len);

        usb_fill_bulk_urb(urb, udev, devinfo->cmd_pipe, iu, sizeof(*iu) + len,
                                                        uas_cmd_cmplt, NULL);
        urb->transfer_flags |= URB_FREE_BUFFER;
 out:
        return urb;
 free:
        usb_free_urb(urb);
        return NULL;
}

/*
 * Why should I request the Status IU before sending the Command IU?  Spec
 * says to, but also says the device may receive them in any order.  Seems
 * daft to me.
 */

static struct urb *uas_submit_sense_urb(struct scsi_cmnd *cmnd,
                                        gfp_t gfp, unsigned int stream)
{
        struct Scsi_Host *shost = cmnd->device->host;
        struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
        struct urb *urb;
        int err;

        urb = uas_alloc_sense_urb(devinfo, gfp, shost, stream);
        if (!urb)
                return NULL;
        usb_anchor_urb(urb, &devinfo->sense_urbs);
        err = usb_submit_urb(urb, gfp);
        if (err) {
                usb_unanchor_urb(urb);
                uas_log_cmd_state(cmnd, __func__);
                shost_printk(KERN_INFO, shost,
                             "sense urb submission error %d stream %d\n",
                             err, stream);
                usb_free_urb(urb);
                return NULL;
        }
        return urb;
}

static int uas_submit_urbs(struct scsi_cmnd *cmnd,
                           struct uas_dev_info *devinfo, gfp_t gfp)
{
        struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
        struct urb *urb;
        int err;

        lockdep_assert_held(&devinfo->lock);
        if (cmdinfo->state & SUBMIT_STATUS_URB) {
                urb = uas_submit_sense_urb(cmnd, gfp, cmdinfo->stream);
                if (!urb)
                        return SCSI_MLQUEUE_DEVICE_BUSY;
                cmdinfo->state &= ~SUBMIT_STATUS_URB;
        }

        if (cmdinfo->state & ALLOC_DATA_IN_URB) {
                cmdinfo->data_in_urb = uas_alloc_data_urb(devinfo, gfp,
                                        devinfo->data_in_pipe, cmdinfo->stream,
                                        cmnd, DMA_FROM_DEVICE);
                if (!cmdinfo->data_in_urb)
                        return SCSI_MLQUEUE_DEVICE_BUSY;
                cmdinfo->state &= ~ALLOC_DATA_IN_URB;
        }

        if (cmdinfo->state & SUBMIT_DATA_IN_URB) {
                usb_anchor_urb(cmdinfo->data_in_urb, &devinfo->data_urbs);
                err = usb_submit_urb(cmdinfo->data_in_urb, gfp);
                if (err) {
                        usb_unanchor_urb(cmdinfo->data_in_urb);
                        uas_log_cmd_state(cmnd, __func__);
                        scmd_printk(KERN_INFO, cmnd,
                                "data in urb submission error %d stream %d\n",
                                err, cmdinfo->data_in_urb->stream_id);
                        return SCSI_MLQUEUE_DEVICE_BUSY;
                }
                cmdinfo->state &= ~SUBMIT_DATA_IN_URB;
                cmdinfo->state |= DATA_IN_URB_INFLIGHT;
        }

        if (cmdinfo->state & ALLOC_DATA_OUT_URB) {
                cmdinfo->data_out_urb = uas_alloc_data_urb(devinfo, gfp,
                                        devinfo->data_out_pipe, cmdinfo->stream,
                                        cmnd, DMA_TO_DEVICE);
                if (!cmdinfo->data_out_urb)
                        return SCSI_MLQUEUE_DEVICE_BUSY;
                cmdinfo->state &= ~ALLOC_DATA_OUT_URB;
        }

        if (cmdinfo->state & SUBMIT_DATA_OUT_URB) {
                usb_anchor_urb(cmdinfo->data_out_urb, &devinfo->data_urbs);
                err = usb_submit_urb(cmdinfo->data_out_urb, gfp);
                if (err) {
                        usb_unanchor_urb(cmdinfo->data_out_urb);
                        uas_log_cmd_state(cmnd, __func__);
                        scmd_printk(KERN_INFO, cmnd,
                                "data out urb submission error %d stream %d\n",
                                err, cmdinfo->data_out_urb->stream_id);
                        return SCSI_MLQUEUE_DEVICE_BUSY;
                }
                cmdinfo->state &= ~SUBMIT_DATA_OUT_URB;
                cmdinfo->state |= DATA_OUT_URB_INFLIGHT;
        }

        if (cmdinfo->state & ALLOC_CMD_URB) {
                cmdinfo->cmd_urb = uas_alloc_cmd_urb(devinfo, gfp, cmnd);
                if (!cmdinfo->cmd_urb)
                        return SCSI_MLQUEUE_DEVICE_BUSY;
                cmdinfo->state &= ~ALLOC_CMD_URB;
        }

        if (cmdinfo->state & SUBMIT_CMD_URB) {
                usb_anchor_urb(cmdinfo->cmd_urb, &devinfo->cmd_urbs);
                err = usb_submit_urb(cmdinfo->cmd_urb, gfp);
                if (err) {
                        usb_unanchor_urb(cmdinfo->cmd_urb);
                        uas_log_cmd_state(cmnd, __func__);
                        scmd_printk(KERN_INFO, cmnd,
                                    "cmd urb submission error %d\n", err);
                        return SCSI_MLQUEUE_DEVICE_BUSY;
                }
                cmdinfo->cmd_urb = NULL;
                cmdinfo->state &= ~SUBMIT_CMD_URB;
                cmdinfo->state |= COMMAND_INFLIGHT;
        }

        return 0;
}

static int uas_queuecommand_lck(struct scsi_cmnd *cmnd,
                                        void (*done)(struct scsi_cmnd *))
{
        struct scsi_device *sdev = cmnd->device;
        struct uas_dev_info *devinfo = sdev->hostdata;
        struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
        unsigned long flags;
        unsigned int stream;
        int err;

        BUILD_BUG_ON(sizeof(struct uas_cmd_info) > sizeof(struct scsi_pointer));

        if ((devinfo->flags & US_FL_NO_ATA_1X) &&
                        (cmnd->cmnd[0] == ATA_12 || cmnd->cmnd[0] == ATA_16)) {
                memcpy(cmnd->sense_buffer, usb_stor_sense_invalidCDB,
                       sizeof(usb_stor_sense_invalidCDB));
                cmnd->result = SAM_STAT_CHECK_CONDITION;
                cmnd->scsi_done(cmnd);
                return 0;
        }

        spin_lock_irqsave(&devinfo->lock, flags);

        if (devinfo->resetting) {
                cmnd->result = DID_ERROR << 16;
                cmnd->scsi_done(cmnd);
                spin_unlock_irqrestore(&devinfo->lock, flags);
                return 0;
        }

        stream = uas_get_tag(cmnd);
        if (devinfo->cmnd[stream - 1]) {
                spin_unlock_irqrestore(&devinfo->lock, flags);
                return SCSI_MLQUEUE_DEVICE_BUSY;
        }

        cmnd->scsi_done = done;

        memset(cmdinfo, 0, sizeof(*cmdinfo));
        cmdinfo->stream = stream;
        cmdinfo->state = SUBMIT_STATUS_URB | ALLOC_CMD_URB | SUBMIT_CMD_URB;

        switch (cmnd->sc_data_direction) {
        case DMA_FROM_DEVICE:
                cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
                break;
        case DMA_BIDIRECTIONAL:
                cmdinfo->state |= ALLOC_DATA_IN_URB | SUBMIT_DATA_IN_URB;
        case DMA_TO_DEVICE:
                cmdinfo->state |= ALLOC_DATA_OUT_URB | SUBMIT_DATA_OUT_URB;
        case DMA_NONE:
                break;
        }

        if (!devinfo->use_streams) {
                cmdinfo->state &= ~(SUBMIT_DATA_IN_URB | SUBMIT_DATA_OUT_URB);
                cmdinfo->stream = 0;
        }

        err = uas_submit_urbs(cmnd, devinfo, GFP_ATOMIC);
        if (err) {
                /* If we did nothing, give up now */
                if (cmdinfo->state & SUBMIT_STATUS_URB) {
                        spin_unlock_irqrestore(&devinfo->lock, flags);
                        return SCSI_MLQUEUE_DEVICE_BUSY;
                }
                uas_add_work(cmdinfo);
        }

        devinfo->cmnd[stream - 1] = cmnd;
        spin_unlock_irqrestore(&devinfo->lock, flags);
        return 0;
}

static DEF_SCSI_QCMD(uas_queuecommand)

/*
 * For now we do not support actually sending an abort to the device, so
 * this eh always fails. Still we must define it to make sure that we've
 * dropped all references to the cmnd in question once this function exits.
 */
static int uas_eh_abort_handler(struct scsi_cmnd *cmnd)
{
        struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
        struct uas_dev_info *devinfo = (void *)cmnd->device->hostdata;
        struct urb *data_in_urb = NULL;
        struct urb *data_out_urb = NULL;
        unsigned long flags;

        spin_lock_irqsave(&devinfo->lock, flags);

        uas_log_cmd_state(cmnd, __func__);

        /* Ensure that try_complete does not call scsi_done */
        cmdinfo->state |= COMMAND_ABORTED;

        /* Drop all refs to this cmnd, kill data urbs to break their ref */
        devinfo->cmnd[uas_get_tag(cmnd) - 1] = NULL;
        if (cmdinfo->state & DATA_IN_URB_INFLIGHT)
                data_in_urb = usb_get_urb(cmdinfo->data_in_urb);
        if (cmdinfo->state & DATA_OUT_URB_INFLIGHT)
                data_out_urb = usb_get_urb(cmdinfo->data_out_urb);

        uas_free_unsubmitted_urbs(cmnd);

        spin_unlock_irqrestore(&devinfo->lock, flags);

        if (data_in_urb) {
                usb_kill_urb(data_in_urb);
                usb_put_urb(data_in_urb);
        }
        if (data_out_urb) {
                usb_kill_urb(data_out_urb);
                usb_put_urb(data_out_urb);
        }

        return FAILED;
}

static int uas_eh_bus_reset_handler(struct scsi_cmnd *cmnd)
{
        struct scsi_device *sdev = cmnd->device;
        struct uas_dev_info *devinfo = sdev->hostdata;
        struct usb_device *udev = devinfo->udev;
        unsigned long flags;
        int err;

        err = usb_lock_device_for_reset(udev, devinfo->intf);
        if (err) {
                shost_printk(KERN_ERR, sdev->host,
                             "%s FAILED to get lock err %d\n", __func__, err);
                return FAILED;
        }

        shost_printk(KERN_INFO, sdev->host, "%s start\n", __func__);

        spin_lock_irqsave(&devinfo->lock, flags);
        devinfo->resetting = 1;
        spin_unlock_irqrestore(&devinfo->lock, flags);

        usb_kill_anchored_urbs(&devinfo->cmd_urbs);
        usb_kill_anchored_urbs(&devinfo->sense_urbs);
        usb_kill_anchored_urbs(&devinfo->data_urbs);
        uas_zap_pending(devinfo, DID_RESET);

        err = usb_reset_device(udev);

        spin_lock_irqsave(&devinfo->lock, flags);
        devinfo->resetting = 0;
        spin_unlock_irqrestore(&devinfo->lock, flags);

        usb_unlock_device(udev);

        if (err) {
                shost_printk(KERN_INFO, sdev->host, "%s FAILED\n", __func__);
                return FAILED;
        }

        shost_printk(KERN_INFO, sdev->host, "%s success\n", __func__);
        return SUCCESS;
}

static int uas_slave_alloc(struct scsi_device *sdev)
{
        sdev->hostdata = (void *)sdev->host->hostdata;

        /* USB has unusual DMA-alignment requirements: Although the
         * starting address of each scatter-gather element doesn't matter,
         * the length of each element except the last must be divisible
         * by the Bulk maxpacket value.  There's currently no way to
         * express this by block-layer constraints, so we'll cop out
         * and simply require addresses to be aligned at 512-byte
         * boundaries.  This is okay since most block I/O involves
         * hardware sectors that are multiples of 512 bytes in length,
         * and since host controllers up through USB 2.0 have maxpacket
         * values no larger than 512.
         *
         * But it doesn't suffice for Wireless USB, where Bulk maxpacket
         * values can be as large as 2048.  To make that work properly
         * will require changes to the block layer.
         */
        blk_queue_update_dma_alignment(sdev->request_queue, (512 - 1));

        return 0;
}

static int uas_slave_configure(struct scsi_device *sdev)
{
        struct uas_dev_info *devinfo = sdev->hostdata;

        if (devinfo->flags & US_FL_NO_REPORT_OPCODES)
                sdev->no_report_opcodes = 1;

        scsi_set_tag_type(sdev, MSG_ORDERED_TAG);
        scsi_activate_tcq(sdev, devinfo->qdepth - 2);
        return 0;
}

static struct scsi_host_template uas_host_template = {
        .module = THIS_MODULE,
        .name = "uas",
        .queuecommand = uas_queuecommand,
        .slave_alloc = uas_slave_alloc,
        .slave_configure = uas_slave_configure,
        .eh_abort_handler = uas_eh_abort_handler,
        .eh_bus_reset_handler = uas_eh_bus_reset_handler,
        .can_queue = 65536,     /* Is there a limit on the _host_ ? */
        .this_id = -1,
        .sg_tablesize = SG_NONE,
        .cmd_per_lun = 1,       /* until we override it */
        .skip_settle_delay = 1,
        .ordered_tag = 1,
};

#define UNUSUAL_DEV(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax, \
                    vendorName, productName, useProtocol, useTransport, \
                    initFunction, flags) \
{ USB_DEVICE_VER(id_vendor, id_product, bcdDeviceMin, bcdDeviceMax), \
        .driver_info = (flags) }

static struct usb_device_id uas_usb_ids[] = {
#       include "unusual_uas.h"
        { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_BULK) },
        { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, USB_PR_UAS) },
        /* 0xaa is a prototype device I happen to have access to */
        { USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, USB_SC_SCSI, 0xaa) },
        { }
};
MODULE_DEVICE_TABLE(usb, uas_usb_ids);

#undef UNUSUAL_DEV

static int uas_switch_interface(struct usb_device *udev,
                                struct usb_interface *intf)
{
        int alt;

        alt = uas_find_uas_alt_setting(intf);
        if (alt < 0)
                return alt;

        return usb_set_interface(udev,
                        intf->altsetting[0].desc.bInterfaceNumber, alt);
}

static int uas_configure_endpoints(struct uas_dev_info *devinfo)
{
        struct usb_host_endpoint *eps[4] = { };
        struct usb_device *udev = devinfo->udev;
        int r;

        devinfo->uas_sense_old = 0;

        r = uas_find_endpoints(devinfo->intf->cur_altsetting, eps);
        if (r)
                return r;

        devinfo->cmd_pipe = usb_sndbulkpipe(udev,
                                            usb_endpoint_num(&eps[0]->desc));
        devinfo->status_pipe = usb_rcvbulkpipe(udev,
                                            usb_endpoint_num(&eps[1]->desc));
        devinfo->data_in_pipe = usb_rcvbulkpipe(udev,
                                            usb_endpoint_num(&eps[2]->desc));
        devinfo->data_out_pipe = usb_sndbulkpipe(udev,
                                            usb_endpoint_num(&eps[3]->desc));

        if (udev->speed != USB_SPEED_SUPER) {
                devinfo->qdepth = 32;
                devinfo->use_streams = 0;
        } else {
                devinfo->qdepth = usb_alloc_streams(devinfo->intf, eps + 1,
                                                    3, MAX_CMNDS, GFP_NOIO);
                if (devinfo->qdepth < 0)
                        return devinfo->qdepth;
                devinfo->use_streams = 1;
        }

        return 0;
}

static void uas_free_streams(struct uas_dev_info *devinfo)
{
        struct usb_device *udev = devinfo->udev;
        struct usb_host_endpoint *eps[3];

        eps[0] = usb_pipe_endpoint(udev, devinfo->status_pipe);
        eps[1] = usb_pipe_endpoint(udev, devinfo->data_in_pipe);
        eps[2] = usb_pipe_endpoint(udev, devinfo->data_out_pipe);
        usb_free_streams(devinfo->intf, eps, 3, GFP_NOIO);
}

static int uas_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
        int result = -ENOMEM;
        struct Scsi_Host *shost = NULL;
        struct uas_dev_info *devinfo;
        struct usb_device *udev = interface_to_usbdev(intf);

        if (!uas_use_uas_driver(intf, id))
                return -ENODEV;

        if (uas_switch_interface(udev, intf))
                return -ENODEV;

        shost = scsi_host_alloc(&uas_host_template,
                                sizeof(struct uas_dev_info));
        if (!shost)
                goto set_alt0;

        shost->max_cmd_len = 16 + 252;
        shost->max_id = 1;
        shost->max_lun = 256;
        shost->max_channel = 0;
        shost->sg_tablesize = udev->bus->sg_tablesize;

        devinfo = (struct uas_dev_info *)shost->hostdata;
        devinfo->intf = intf;
        devinfo->udev = udev;
        devinfo->resetting = 0;
        devinfo->shutdown = 0;
        devinfo->flags = id->driver_info;
        usb_stor_adjust_quirks(udev, &devinfo->flags);
        init_usb_anchor(&devinfo->cmd_urbs);
        init_usb_anchor(&devinfo->sense_urbs);
        init_usb_anchor(&devinfo->data_urbs);
        spin_lock_init(&devinfo->lock);
        INIT_WORK(&devinfo->work, uas_do_work);

        result = uas_configure_endpoints(devinfo);
        if (result)
                goto set_alt0;

        result = scsi_init_shared_tag_map(shost, devinfo->qdepth - 2);
        if (result)
                goto free_streams;

        usb_set_intfdata(intf, shost);
        result = scsi_add_host(shost, &intf->dev);
        if (result)
                goto free_streams;

        scsi_scan_host(shost);
        return result;

free_streams:
        uas_free_streams(devinfo);
        usb_set_intfdata(intf, NULL);
set_alt0:
        usb_set_interface(udev, intf->altsetting[0].desc.bInterfaceNumber, 0);
        if (shost)
                scsi_host_put(shost);
        return result;
}

static int uas_pre_reset(struct usb_interface *intf)
{
        struct Scsi_Host *shost = usb_get_intfdata(intf);
        struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
        unsigned long flags;

        if (devinfo->shutdown)
                return 0;

        /* Block new requests */
        spin_lock_irqsave(shost->host_lock, flags);
        scsi_block_requests(shost);
        spin_unlock_irqrestore(shost->host_lock, flags);

        /* Wait for any pending requests to complete */
        flush_work(&devinfo->work);
        if (usb_wait_anchor_empty_timeout(&devinfo->sense_urbs, 5000) == 0) {
                shost_printk(KERN_ERR, shost, "%s: timed out\n", __func__);
                return 1;
        }

        uas_free_streams(devinfo);

        return 0;
}

static int uas_post_reset(struct usb_interface *intf)
{
        struct Scsi_Host *shost = usb_get_intfdata(intf);
        struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
        unsigned long flags;

        if (devinfo->shutdown)
                return 0;

        if (uas_configure_endpoints(devinfo) != 0) {
                shost_printk(KERN_ERR, shost,
                             "%s: alloc streams error after reset", __func__);
                return 1;
        }

        spin_lock_irqsave(shost->host_lock, flags);
        scsi_report_bus_reset(shost, 0);
        spin_unlock_irqrestore(shost->host_lock, flags);

        scsi_unblock_requests(shost);

        return 0;
}

static int uas_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct Scsi_Host *shost = usb_get_intfdata(intf);
        struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;

        /* Wait for any pending requests to complete */
        flush_work(&devinfo->work);
        if (usb_wait_anchor_empty_timeout(&devinfo->sense_urbs, 5000) == 0) {
                shost_printk(KERN_ERR, shost, "%s: timed out\n", __func__);
                return -ETIME;
        }

        return 0;
}

static int uas_resume(struct usb_interface *intf)
{
        return 0;
}

static int uas_reset_resume(struct usb_interface *intf)
{
        struct Scsi_Host *shost = usb_get_intfdata(intf);
        struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
        unsigned long flags;

        if (uas_configure_endpoints(devinfo) != 0) {
                shost_printk(KERN_ERR, shost,
                             "%s: alloc streams error after reset", __func__);
                return -EIO;
        }

        spin_lock_irqsave(shost->host_lock, flags);
        scsi_report_bus_reset(shost, 0);
        spin_unlock_irqrestore(shost->host_lock, flags);

        return 0;
}

static void uas_disconnect(struct usb_interface *intf)
{
        struct Scsi_Host *shost = usb_get_intfdata(intf);
        struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;
        unsigned long flags;

        spin_lock_irqsave(&devinfo->lock, flags);
        devinfo->resetting = 1;
        spin_unlock_irqrestore(&devinfo->lock, flags);

        cancel_work_sync(&devinfo->work);
        usb_kill_anchored_urbs(&devinfo->cmd_urbs);
        usb_kill_anchored_urbs(&devinfo->sense_urbs);
        usb_kill_anchored_urbs(&devinfo->data_urbs);
        uas_zap_pending(devinfo, DID_NO_CONNECT);

        scsi_remove_host(shost);
        uas_free_streams(devinfo);
        scsi_host_put(shost);
}

/*
 * Put the device back in usb-storage mode on shutdown, as some BIOS-es
 * hang on reboot when the device is still in uas mode. Note the reset is
 * necessary as some devices won't revert to usb-storage mode without it.
 */
static void uas_shutdown(struct device *dev)
{
        struct usb_interface *intf = to_usb_interface(dev);
        struct usb_device *udev = interface_to_usbdev(intf);
        struct Scsi_Host *shost = usb_get_intfdata(intf);
        struct uas_dev_info *devinfo = (struct uas_dev_info *)shost->hostdata;

        if (system_state != SYSTEM_RESTART)
                return;

        devinfo->shutdown = 1;
        uas_free_streams(devinfo);
        usb_set_interface(udev, intf->altsetting[0].desc.bInterfaceNumber, 0);
        usb_reset_device(udev);
}

static struct usb_driver uas_driver = {
        .name = "uas",
        .probe = uas_probe,
        .disconnect = uas_disconnect,
        .pre_reset = uas_pre_reset,
        .post_reset = uas_post_reset,
        .suspend = uas_suspend,
        .resume = uas_resume,
        .reset_resume = uas_reset_resume,
        .drvwrap.driver.shutdown = uas_shutdown,
        .id_table = uas_usb_ids,
};

module_usb_driver(uas_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR(
        "Hans de Goede <hdegoede@redhat.com>, Matthew Wilcox and Sarah Sharp");