firewire: Use only a wait queue and terminate poll and read on device removal.

[mirror_ubuntu-artful-kernel.git] / drivers / firewire / fw-device.c

/*                                              -*- c-basic-offset: 8 -*-
 *
 * fw-device.c - Device probing and sysfs code.
 *
 * Copyright (C) 2005-2006  Kristian Hoegsberg <krh@bitplanet.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <linux/module.h>
#include <linux/wait.h>
#include <linux/errno.h>
#include <linux/kthread.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/idr.h>
#include "fw-transaction.h"
#include "fw-topology.h"
#include "fw-device.h"

void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
{
        ci->p = p + 1;
        ci->end = ci->p + (p[0] >> 16);
}
EXPORT_SYMBOL(fw_csr_iterator_init);

int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
{
        *key = *ci->p >> 24;
        *value = *ci->p & 0xffffff;

        return ci->p++ < ci->end;
}
EXPORT_SYMBOL(fw_csr_iterator_next);

static int is_fw_unit(struct device *dev);

static int match_unit_directory(u32 * directory, const struct fw_device_id *id)
{
        struct fw_csr_iterator ci;
        int key, value, match;

        match = 0;
        fw_csr_iterator_init(&ci, directory);
        while (fw_csr_iterator_next(&ci, &key, &value)) {
                if (key == CSR_VENDOR && value == id->vendor)
                        match |= FW_MATCH_VENDOR;
                if (key == CSR_MODEL && value == id->model)
                        match |= FW_MATCH_MODEL;
                if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
                        match |= FW_MATCH_SPECIFIER_ID;
                if (key == CSR_VERSION && value == id->version)
                        match |= FW_MATCH_VERSION;
        }

        return (match & id->match_flags) == id->match_flags;
}

static int fw_unit_match(struct device *dev, struct device_driver *drv)
{
        struct fw_unit *unit = fw_unit(dev);
        struct fw_driver *driver = fw_driver(drv);
        int i;

        /* We only allow binding to fw_units. */
        if (!is_fw_unit(dev))
                return 0;

        for (i = 0; driver->id_table[i].match_flags != 0; i++) {
                if (match_unit_directory(unit->directory, &driver->id_table[i]))
                        return 1;
        }

        return 0;
}

static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
{
        struct fw_device *device = fw_device(unit->device.parent);
        struct fw_csr_iterator ci;

        int key, value;
        int vendor = 0;
        int model = 0;
        int specifier_id = 0;
        int version = 0;

        fw_csr_iterator_init(&ci, &device->config_rom[5]);
        while (fw_csr_iterator_next(&ci, &key, &value)) {
                switch (key) {
                case CSR_VENDOR:
                        vendor = value;
                        break;
                case CSR_MODEL:
                        model = value;
                        break;
                }
        }

        fw_csr_iterator_init(&ci, unit->directory);
        while (fw_csr_iterator_next(&ci, &key, &value)) {
                switch (key) {
                case CSR_SPECIFIER_ID:
                        specifier_id = value;
                        break;
                case CSR_VERSION:
                        version = value;
                        break;
                }
        }

        return snprintf(buffer, buffer_size,
                        "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
                        vendor, model, specifier_id, version);
}

static int
fw_unit_uevent(struct device *dev, char **envp, int num_envp,
               char *buffer, int buffer_size)
{
        struct fw_unit *unit = fw_unit(dev);
        char modalias[64];
        int length = 0;
        int i = 0;

        if (!is_fw_unit(dev))
                goto out;

        get_modalias(unit, modalias, sizeof modalias);

        if (add_uevent_var(envp, num_envp, &i,
                           buffer, buffer_size, &length,
                           "MODALIAS=%s", modalias))
                return -ENOMEM;

 out:
        envp[i] = NULL;

        return 0;
}

struct bus_type fw_bus_type = {
        .name = "firewire",
        .match = fw_unit_match,
        .uevent = fw_unit_uevent,
};
EXPORT_SYMBOL(fw_bus_type);

extern struct fw_device *fw_device_get(struct fw_device *device)
{
        get_device(&device->device);

        return device;
}

extern void fw_device_put(struct fw_device *device)
{
        put_device(&device->device);
}

static void fw_device_release(struct device *dev)
{
        struct fw_device *device = fw_device(dev);
        unsigned long flags;

        /* Take the card lock so we don't set this to NULL while a
         * FW_NODE_UPDATED callback is being handled. */
        spin_lock_irqsave(&device->card->lock, flags);
        device->node->data = NULL;
        spin_unlock_irqrestore(&device->card->lock, flags);

        fw_node_put(device->node);
        fw_card_put(device->card);
        kfree(device->config_rom);
        kfree(device);
}

int fw_device_enable_phys_dma(struct fw_device *device)
{
        return device->card->driver->enable_phys_dma(device->card,
                                                     device->node_id,
                                                     device->generation);
}
EXPORT_SYMBOL(fw_device_enable_phys_dma);

static ssize_t
show_modalias_attribute(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        struct fw_unit *unit = fw_unit(dev);
        int length;

        length = get_modalias(unit, buf, PAGE_SIZE);
        strcpy(buf + length, "\n");

        return length + 1;
}

static struct device_attribute modalias_attribute = {
        .attr = { .name = "modalias", .mode = S_IRUGO, },
        .show = show_modalias_attribute,
};

static ssize_t
show_config_rom_attribute(struct device *dev,
                          struct device_attribute *attr, char *buf)
{
        struct fw_device *device = fw_device(dev);

        memcpy(buf, device->config_rom, device->config_rom_length * 4);

        return device->config_rom_length * 4;
}

static struct device_attribute config_rom_attribute = {
        .attr = {.name = "config_rom", .mode = S_IRUGO,},
        .show = show_config_rom_attribute,
};

static ssize_t
show_rom_index_attribute(struct device *dev,
                         struct device_attribute *attr, char *buf)
{
        struct fw_device *device = fw_device(dev->parent);
        struct fw_unit *unit = fw_unit(dev);

        return snprintf(buf, PAGE_SIZE, "%d\n",
                        unit->directory - device->config_rom);
}

static struct device_attribute rom_index_attribute = {
        .attr = { .name = "rom_index", .mode = S_IRUGO, },
        .show = show_rom_index_attribute,
};

struct read_quadlet_callback_data {
        struct completion done;
        int rcode;
        u32 data;
};

static void
complete_transaction(struct fw_card *card, int rcode,
                     void *payload, size_t length, void *data)
{
        struct read_quadlet_callback_data *callback_data = data;

        if (rcode == RCODE_COMPLETE)
                callback_data->data = be32_to_cpu(*(__be32 *)payload);
        callback_data->rcode = rcode;
        complete(&callback_data->done);
}

static int read_rom(struct fw_device *device, int index, u32 * data)
{
        struct read_quadlet_callback_data callback_data;
        struct fw_transaction t;
        u64 offset;

        init_completion(&callback_data.done);

        offset = 0xfffff0000400ULL + index * 4;
        fw_send_request(device->card, &t, TCODE_READ_QUADLET_REQUEST,
                        device->node_id,
                        device->generation, SCODE_100,
                        offset, NULL, 4, complete_transaction, &callback_data);

        wait_for_completion(&callback_data.done);

        *data = callback_data.data;

        return callback_data.rcode;
}

static int read_bus_info_block(struct fw_device *device)
{
        static u32 rom[256];
        u32 stack[16], sp, key;
        int i, end, length;

        /* First read the bus info block. */
        for (i = 0; i < 5; i++) {
                if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
                        return -1;
                /* As per IEEE1212 7.2, during power-up, devices can
                 * reply with a 0 for the first quadlet of the config
                 * rom to indicate that they are booting (for example,
                 * if the firmware is on the disk of a external
                 * harddisk).  In that case we just fail, and the
                 * retry mechanism will try again later. */
                if (i == 0 && rom[i] == 0)
                        return -1;
        }

        /* Now parse the config rom.  The config rom is a recursive
         * directory structure so we parse it using a stack of
         * references to the blocks that make up the structure.  We
         * push a reference to the root directory on the stack to
         * start things off. */
        length = i;
        sp = 0;
        stack[sp++] = 0xc0000005;
        while (sp > 0) {
                /* Pop the next block reference of the stack.  The
                 * lower 24 bits is the offset into the config rom,
                 * the upper 8 bits are the type of the reference the
                 * block. */
                key = stack[--sp];
                i = key & 0xffffff;
                if (i >= ARRAY_SIZE(rom))
                        /* The reference points outside the standard
                         * config rom area, something's fishy. */
                        return -1;

                /* Read header quadlet for the block to get the length. */
                if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
                        return -1;
                end = i + (rom[i] >> 16) + 1;
                i++;
                if (end > ARRAY_SIZE(rom))
                        /* This block extends outside standard config
                         * area (and the array we're reading it
                         * into).  That's broken, so ignore this
                         * device. */
                        return -1;

                /* Now read in the block.  If this is a directory
                 * block, check the entries as we read them to see if
                 * it references another block, and push it in that case. */
                while (i < end) {
                        if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
                                return -1;
                        if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
                            sp < ARRAY_SIZE(stack))
                                stack[sp++] = i + rom[i];
                        i++;
                }
                if (length < i)
                        length = i;
        }

        device->config_rom = kmalloc(length * 4, GFP_KERNEL);
        if (device->config_rom == NULL)
                return -1;
        memcpy(device->config_rom, rom, length * 4);
        device->config_rom_length = length;

        return 0;
}

static void fw_unit_release(struct device *dev)
{
        struct fw_unit *unit = fw_unit(dev);

        kfree(unit);
}

static int is_fw_unit(struct device *dev)
{
        return dev->release == fw_unit_release;
}

static void create_units(struct fw_device *device)
{
        struct fw_csr_iterator ci;
        struct fw_unit *unit;
        int key, value, i;

        i = 0;
        fw_csr_iterator_init(&ci, &device->config_rom[5]);
        while (fw_csr_iterator_next(&ci, &key, &value)) {
                if (key != (CSR_UNIT | CSR_DIRECTORY))
                        continue;

                /* Get the address of the unit directory and try to
                 * match the drivers id_tables against it. */
                unit = kzalloc(sizeof *unit, GFP_KERNEL);
                if (unit == NULL) {
                        fw_error("failed to allocate memory for unit\n");
                        continue;
                }

                unit->directory = ci.p + value - 1;
                unit->device.bus = &fw_bus_type;
                unit->device.release = fw_unit_release;
                unit->device.parent = &device->device;
                snprintf(unit->device.bus_id, sizeof unit->device.bus_id,
                         "%s.%d", device->device.bus_id, i++);

                if (device_register(&unit->device) < 0) {
                        kfree(unit);
                        continue;
                }

                if (device_create_file(&unit->device, &modalias_attribute) < 0) {
                        device_unregister(&unit->device);
                        kfree(unit);
                }

                if (device_create_file(&unit->device, &rom_index_attribute) < 0) {
                        device_unregister(&unit->device);
                        kfree(unit);
                }
        }
}

static int shutdown_unit(struct device *device, void *data)
{
        struct fw_unit *unit = fw_unit(device);

        if (is_fw_unit(device)) {
                device_remove_file(&unit->device, &modalias_attribute);
                device_unregister(&unit->device);
        }

        return 0;
}

static DEFINE_IDR(fw_device_idr);
int fw_cdev_major;

struct fw_device *fw_device_from_devt(dev_t devt)
{
        struct fw_device *device;

        down_read(&fw_bus_type.subsys.rwsem);
        device = idr_find(&fw_device_idr, MINOR(devt));
        up_read(&fw_bus_type.subsys.rwsem);

        return device;
}

static void fw_device_shutdown(struct work_struct *work)
{
        struct fw_device *device =
                container_of(work, struct fw_device, work.work);
        int minor = MINOR(device->device.devt);

        down_write(&fw_bus_type.subsys.rwsem);
        idr_remove(&fw_device_idr, minor);
        up_write(&fw_bus_type.subsys.rwsem);

        fw_device_cdev_remove(device);
        device_remove_file(&device->device, &config_rom_attribute);
        device_for_each_child(&device->device, NULL, shutdown_unit);
        device_unregister(&device->device);
}

/* These defines control the retry behavior for reading the config
 * rom.  It shouldn't be necessary to tweak these; if the device
 * doesn't respond to a config rom read within 10 seconds, it's not
 * going to respond at all.  As for the initial delay, a lot of
 * devices will be able to respond within half a second after bus
 * reset.  On the other hand, it's not really worth being more
 * aggressive than that, since it scales pretty well; if 10 devices
 * are plugged in, they're all getting read within one second. */

#define MAX_RETRIES     5
#define RETRY_DELAY     (2 * HZ)
#define INITIAL_DELAY   (HZ / 2)

static void fw_device_init(struct work_struct *work)
{
        struct fw_device *device =
                container_of(work, struct fw_device, work.work);
        int minor, err;

        /* All failure paths here set node->data to NULL, so that we
         * don't try to do device_for_each_child() on a kfree()'d
         * device. */

        if (read_bus_info_block(device) < 0) {
                if (device->config_rom_retries < MAX_RETRIES) {
                        device->config_rom_retries++;
                        schedule_delayed_work(&device->work, RETRY_DELAY);
                } else {
                        fw_notify("giving up on config rom for node id %x\n",
                                  device->node_id);
                        if (device->node == device->card->root_node)
                                schedule_delayed_work(&device->card->work, 0);
                        fw_device_release(&device->device);
                }
                return;
        }

        err = -ENOMEM;
        down_write(&fw_bus_type.subsys.rwsem);
        if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
                err = idr_get_new(&fw_device_idr, device, &minor);
        up_write(&fw_bus_type.subsys.rwsem);
        if (err < 0)
                goto error;

        device->device.bus = &fw_bus_type;
        device->device.release = fw_device_release;
        device->device.parent = device->card->device;
        device->device.devt = MKDEV(fw_cdev_major, minor);
        snprintf(device->device.bus_id, sizeof device->device.bus_id,
                 "fw%d", minor);

        if (device_add(&device->device)) {
                fw_error("Failed to add device.\n");
                goto error_with_cdev;
        }

        if (device_create_file(&device->device, &config_rom_attribute) < 0) {
                fw_error("Failed to create config rom file.\n");
                goto error_with_device;
        }

        create_units(device);

        /* Transition the device to running state.  If it got pulled
         * out from under us while we did the intialization work, we
         * have to shut down the device again here.  Normally, though,
         * fw_node_event will be responsible for shutting it down when
         * necessary.  We have to use the atomic cmpxchg here to avoid
         * racing with the FW_NODE_DESTROYED case in
         * fw_node_event(). */
        if (atomic_cmpxchg(&device->state,
                    FW_DEVICE_INITIALIZING,
                    FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
                fw_device_shutdown(&device->work.work);
        else
                fw_notify("created new fw device %s (%d config rom retries)\n",
                          device->device.bus_id, device->config_rom_retries);

        /* Reschedule the IRM work if we just finished reading the
         * root node config rom.  If this races with a bus reset we
         * just end up running the IRM work a couple of extra times -
         * pretty harmless. */
        if (device->node == device->card->root_node)
                schedule_delayed_work(&device->card->work, 0);

        return;

 error_with_device:
        device_del(&device->device);
 error_with_cdev:
        down_write(&fw_bus_type.subsys.rwsem);
        idr_remove(&fw_device_idr, minor);
        up_write(&fw_bus_type.subsys.rwsem);
 error:
        put_device(&device->device);
}

static int update_unit(struct device *dev, void *data)
{
        struct fw_unit *unit = fw_unit(dev);
        struct fw_driver *driver = (struct fw_driver *)dev->driver;

        if (is_fw_unit(dev) && driver != NULL && driver->update != NULL)
                driver->update(unit);

        return 0;
}

static void fw_device_update(struct work_struct *work)
{
        struct fw_device *device =
                container_of(work, struct fw_device, work.work);

        fw_device_cdev_update(device);
        device_for_each_child(&device->device, NULL, update_unit);
}

void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
{
        struct fw_device *device;

        switch (event) {
        case FW_NODE_CREATED:
        case FW_NODE_LINK_ON:
                if (!node->link_on)
                        break;

                device = kzalloc(sizeof(*device), GFP_ATOMIC);
                if (device == NULL)
                        break;

                /* Do minimal intialization of the device here, the
                 * rest will happen in fw_device_init().  We need the
                 * card and node so we can read the config rom and we
                 * need to do device_initialize() now so
                 * device_for_each_child() in FW_NODE_UPDATED is
                 * doesn't freak out. */
                device_initialize(&device->device);
                atomic_set(&device->state, FW_DEVICE_INITIALIZING);
                device->card = fw_card_get(card);
                device->node = fw_node_get(node);
                device->node_id = node->node_id;
                device->generation = card->generation;
                INIT_LIST_HEAD(&device->client_list);

                /* Set the node data to point back to this device so
                 * FW_NODE_UPDATED callbacks can update the node_id
                 * and generation for the device. */
                node->data = device;

                /* Many devices are slow to respond after bus resets,
                 * especially if they are bus powered and go through
                 * power-up after getting plugged in.  We schedule the
                 * first config rom scan half a second after bus reset. */
                INIT_DELAYED_WORK(&device->work, fw_device_init);
                schedule_delayed_work(&device->work, INITIAL_DELAY);
                break;

        case FW_NODE_UPDATED:
                if (!node->link_on || node->data == NULL)
                        break;

                device = node->data;
                device->node_id = node->node_id;
                device->generation = card->generation;
                if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
                        PREPARE_DELAYED_WORK(&device->work, fw_device_update);
                        schedule_delayed_work(&device->work, 0);
                }
                break;

        case FW_NODE_DESTROYED:
        case FW_NODE_LINK_OFF:
                if (!node->data)
                        break;

                /* Destroy the device associated with the node.  There
                 * are two cases here: either the device is fully
                 * initialized (FW_DEVICE_RUNNING) or we're in the
                 * process of reading its config rom
                 * (FW_DEVICE_INITIALIZING).  If it is fully
                 * initialized we can reuse device->work to schedule a
                 * full fw_device_shutdown().  If not, there's work
                 * scheduled to read it's config rom, and we just put
                 * the device in shutdown state to have that code fail
                 * to create the device. */
                device = node->data;
                if (atomic_xchg(&device->state,
                                FW_DEVICE_SHUTDOWN) == FW_DEVICE_RUNNING) {
                        PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
                        schedule_delayed_work(&device->work, 0);
                }
                break;
        }
}