firewire: cdev: prevent race between first get_info ioctl

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / firewire / core-cdev.c

/*
 * Char device for device raw access
 *
 * Copyright (C) 2005-2007  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/compat.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/firewire.h>
#include <linux/firewire-cdev.h>
#include <linux/idr.h>
#include <linux/irqflags.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/time.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <linux/wait.h>
#include <linux/workqueue.h>

#include <asm/system.h>

#include "core.h"

struct client {
        u32 version;
        struct fw_device *device;

        spinlock_t lock;
        bool in_shutdown;
        struct idr resource_idr;
        struct list_head event_list;
        wait_queue_head_t wait;
        u64 bus_reset_closure;

        struct fw_iso_context *iso_context;
        u64 iso_closure;
        struct fw_iso_buffer buffer;
        unsigned long vm_start;

        struct list_head link;
        struct kref kref;
};

static inline void client_get(struct client *client)
{
        kref_get(&client->kref);
}

static void client_release(struct kref *kref)
{
        struct client *client = container_of(kref, struct client, kref);

        fw_device_put(client->device);
        kfree(client);
}

static void client_put(struct client *client)
{
        kref_put(&client->kref, client_release);
}

struct client_resource;
typedef void (*client_resource_release_fn_t)(struct client *,
                                             struct client_resource *);
struct client_resource {
        client_resource_release_fn_t release;
        int handle;
};

struct address_handler_resource {
        struct client_resource resource;
        struct fw_address_handler handler;
        __u64 closure;
        struct client *client;
};

struct outbound_transaction_resource {
        struct client_resource resource;
        struct fw_transaction transaction;
};

struct inbound_transaction_resource {
        struct client_resource resource;
        struct fw_request *request;
        void *data;
        size_t length;
};

struct descriptor_resource {
        struct client_resource resource;
        struct fw_descriptor descriptor;
        u32 data[0];
};

struct iso_resource {
        struct client_resource resource;
        struct client *client;
        /* Schedule work and access todo only with client->lock held. */
        struct delayed_work work;
        enum {ISO_RES_ALLOC, ISO_RES_REALLOC, ISO_RES_DEALLOC,
              ISO_RES_ALLOC_ONCE, ISO_RES_DEALLOC_ONCE,} todo;
        int generation;
        u64 channels;
        s32 bandwidth;
        __be32 transaction_data[2];
        struct iso_resource_event *e_alloc, *e_dealloc;
};

static void release_iso_resource(struct client *, struct client_resource *);

static void schedule_iso_resource(struct iso_resource *r, unsigned long delay)
{
        client_get(r->client);
        if (!schedule_delayed_work(&r->work, delay))
                client_put(r->client);
}

static void schedule_if_iso_resource(struct client_resource *resource)
{
        if (resource->release == release_iso_resource)
                schedule_iso_resource(container_of(resource,
                                        struct iso_resource, resource), 0);
}

/*
 * dequeue_event() just kfree()'s the event, so the event has to be
 * the first field in a struct XYZ_event.
 */
struct event {
        struct { void *data; size_t size; } v[2];
        struct list_head link;
};

struct bus_reset_event {
        struct event event;
        struct fw_cdev_event_bus_reset reset;
};

struct outbound_transaction_event {
        struct event event;
        struct client *client;
        struct outbound_transaction_resource r;
        struct fw_cdev_event_response response;
};

struct inbound_transaction_event {
        struct event event;
        struct fw_cdev_event_request request;
};

struct iso_interrupt_event {
        struct event event;
        struct fw_cdev_event_iso_interrupt interrupt;
};

struct iso_resource_event {
        struct event event;
        struct fw_cdev_event_iso_resource iso_resource;
};

static inline void __user *u64_to_uptr(__u64 value)
{
        return (void __user *)(unsigned long)value;
}

static inline __u64 uptr_to_u64(void __user *ptr)
{
        return (__u64)(unsigned long)ptr;
}

static int fw_device_op_open(struct inode *inode, struct file *file)
{
        struct fw_device *device;
        struct client *client;

        device = fw_device_get_by_devt(inode->i_rdev);
        if (device == NULL)
                return -ENODEV;

        if (fw_device_is_shutdown(device)) {
                fw_device_put(device);
                return -ENODEV;
        }

        client = kzalloc(sizeof(*client), GFP_KERNEL);
        if (client == NULL) {
                fw_device_put(device);
                return -ENOMEM;
        }

        client->device = device;
        spin_lock_init(&client->lock);
        idr_init(&client->resource_idr);
        INIT_LIST_HEAD(&client->event_list);
        init_waitqueue_head(&client->wait);
        INIT_LIST_HEAD(&client->link);
        kref_init(&client->kref);

        file->private_data = client;

        return nonseekable_open(inode, file);
}

static void queue_event(struct client *client, struct event *event,
                        void *data0, size_t size0, void *data1, size_t size1)
{
        unsigned long flags;

        event->v[0].data = data0;
        event->v[0].size = size0;
        event->v[1].data = data1;
        event->v[1].size = size1;

        spin_lock_irqsave(&client->lock, flags);
        if (client->in_shutdown)
                kfree(event);
        else
                list_add_tail(&event->link, &client->event_list);
        spin_unlock_irqrestore(&client->lock, flags);

        wake_up_interruptible(&client->wait);
}

static int dequeue_event(struct client *client,
                         char __user *buffer, size_t count)
{
        struct event *event;
        size_t size, total;
        int i, ret;

        ret = wait_event_interruptible(client->wait,
                        !list_empty(&client->event_list) ||
                        fw_device_is_shutdown(client->device));
        if (ret < 0)
                return ret;

        if (list_empty(&client->event_list) &&
                       fw_device_is_shutdown(client->device))
                return -ENODEV;

        spin_lock_irq(&client->lock);
        event = list_first_entry(&client->event_list, struct event, link);
        list_del(&event->link);
        spin_unlock_irq(&client->lock);

        total = 0;
        for (i = 0; i < ARRAY_SIZE(event->v) && total < count; i++) {
                size = min(event->v[i].size, count - total);
                if (copy_to_user(buffer + total, event->v[i].data, size)) {
                        ret = -EFAULT;
                        goto out;
                }
                total += size;
        }
        ret = total;

 out:
        kfree(event);

        return ret;
}

static ssize_t fw_device_op_read(struct file *file, char __user *buffer,
                                 size_t count, loff_t *offset)
{
        struct client *client = file->private_data;

        return dequeue_event(client, buffer, count);
}

static void fill_bus_reset_event(struct fw_cdev_event_bus_reset *event,
                                 struct client *client)
{
        struct fw_card *card = client->device->card;

        spin_lock_irq(&card->lock);

        event->closure       = client->bus_reset_closure;
        event->type          = FW_CDEV_EVENT_BUS_RESET;
        event->generation    = client->device->generation;
        event->node_id       = client->device->node_id;
        event->local_node_id = card->local_node->node_id;
        event->bm_node_id    = 0; /* FIXME: We don't track the BM. */
        event->irm_node_id   = card->irm_node->node_id;
        event->root_node_id  = card->root_node->node_id;

        spin_unlock_irq(&card->lock);
}

static void for_each_client(struct fw_device *device,
                            void (*callback)(struct client *client))
{
        struct client *c;

        mutex_lock(&device->client_list_mutex);
        list_for_each_entry(c, &device->client_list, link)
                callback(c);
        mutex_unlock(&device->client_list_mutex);
}

static int schedule_reallocations(int id, void *p, void *data)
{
        schedule_if_iso_resource(p);

        return 0;
}

static void queue_bus_reset_event(struct client *client)
{
        struct bus_reset_event *e;

        e = kzalloc(sizeof(*e), GFP_KERNEL);
        if (e == NULL) {
                fw_notify("Out of memory when allocating bus reset event\n");
                return;
        }

        fill_bus_reset_event(&e->reset, client);

        queue_event(client, &e->event,
                    &e->reset, sizeof(e->reset), NULL, 0);

        spin_lock_irq(&client->lock);
        idr_for_each(&client->resource_idr, schedule_reallocations, client);
        spin_unlock_irq(&client->lock);
}

void fw_device_cdev_update(struct fw_device *device)
{
        for_each_client(device, queue_bus_reset_event);
}

static void wake_up_client(struct client *client)
{
        wake_up_interruptible(&client->wait);
}

void fw_device_cdev_remove(struct fw_device *device)
{
        for_each_client(device, wake_up_client);
}

union ioctl_arg {
        struct fw_cdev_get_info                 get_info;
        struct fw_cdev_send_request             send_request;
        struct fw_cdev_allocate                 allocate;
        struct fw_cdev_deallocate               deallocate;
        struct fw_cdev_send_response            send_response;
        struct fw_cdev_initiate_bus_reset       initiate_bus_reset;
        struct fw_cdev_add_descriptor           add_descriptor;
        struct fw_cdev_remove_descriptor        remove_descriptor;
        struct fw_cdev_create_iso_context       create_iso_context;
        struct fw_cdev_queue_iso                queue_iso;
        struct fw_cdev_start_iso                start_iso;
        struct fw_cdev_stop_iso                 stop_iso;
        struct fw_cdev_get_cycle_timer          get_cycle_timer;
        struct fw_cdev_allocate_iso_resource    allocate_iso_resource;
        struct fw_cdev_send_stream_packet       send_stream_packet;
        struct fw_cdev_get_cycle_timer2         get_cycle_timer2;
};

static int ioctl_get_info(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_get_info *a = &arg->get_info;
        struct fw_cdev_event_bus_reset bus_reset;
        unsigned long ret = 0;

        client->version = a->version;
        a->version = FW_CDEV_VERSION;
        a->card = client->device->card->index;

        down_read(&fw_device_rwsem);

        if (a->rom != 0) {
                size_t want = a->rom_length;
                size_t have = client->device->config_rom_length * 4;

                ret = copy_to_user(u64_to_uptr(a->rom),
                                   client->device->config_rom, min(want, have));
        }
        a->rom_length = client->device->config_rom_length * 4;

        up_read(&fw_device_rwsem);

        if (ret != 0)
                return -EFAULT;

        mutex_lock(&client->device->client_list_mutex);

        client->bus_reset_closure = a->bus_reset_closure;
        if (a->bus_reset != 0) {
                fill_bus_reset_event(&bus_reset, client);
                ret = copy_to_user(u64_to_uptr(a->bus_reset),
                                   &bus_reset, sizeof(bus_reset));
        }
        if (ret == 0 && list_empty(&client->link))
                list_add_tail(&client->link, &client->device->client_list);

        mutex_unlock(&client->device->client_list_mutex);

        return ret ? -EFAULT : 0;
}

static int add_client_resource(struct client *client,
                               struct client_resource *resource, gfp_t gfp_mask)
{
        unsigned long flags;
        int ret;

 retry:
        if (idr_pre_get(&client->resource_idr, gfp_mask) == 0)
                return -ENOMEM;

        spin_lock_irqsave(&client->lock, flags);
        if (client->in_shutdown)
                ret = -ECANCELED;
        else
                ret = idr_get_new(&client->resource_idr, resource,
                                  &resource->handle);
        if (ret >= 0) {
                client_get(client);
                schedule_if_iso_resource(resource);
        }
        spin_unlock_irqrestore(&client->lock, flags);

        if (ret == -EAGAIN)
                goto retry;

        return ret < 0 ? ret : 0;
}

static int release_client_resource(struct client *client, u32 handle,
                                   client_resource_release_fn_t release,
                                   struct client_resource **return_resource)
{
        struct client_resource *resource;

        spin_lock_irq(&client->lock);
        if (client->in_shutdown)
                resource = NULL;
        else
                resource = idr_find(&client->resource_idr, handle);
        if (resource && resource->release == release)
                idr_remove(&client->resource_idr, handle);
        spin_unlock_irq(&client->lock);

        if (!(resource && resource->release == release))
                return -EINVAL;

        if (return_resource)
                *return_resource = resource;
        else
                resource->release(client, resource);

        client_put(client);

        return 0;
}

static void release_transaction(struct client *client,
                                struct client_resource *resource)
{
        struct outbound_transaction_resource *r = container_of(resource,
                        struct outbound_transaction_resource, resource);

        fw_cancel_transaction(client->device->card, &r->transaction);
}

static void complete_transaction(struct fw_card *card, int rcode,
                                 void *payload, size_t length, void *data)
{
        struct outbound_transaction_event *e = data;
        struct fw_cdev_event_response *rsp = &e->response;
        struct client *client = e->client;
        unsigned long flags;

        if (length < rsp->length)
                rsp->length = length;
        if (rcode == RCODE_COMPLETE)
                memcpy(rsp->data, payload, rsp->length);

        spin_lock_irqsave(&client->lock, flags);
        /*
         * 1. If called while in shutdown, the idr tree must be left untouched.
         *    The idr handle will be removed and the client reference will be
         *    dropped later.
         * 2. If the call chain was release_client_resource ->
         *    release_transaction -> complete_transaction (instead of a normal
         *    conclusion of the transaction), i.e. if this resource was already
         *    unregistered from the idr, the client reference will be dropped
         *    by release_client_resource and we must not drop it here.
         */
        if (!client->in_shutdown &&
            idr_find(&client->resource_idr, e->r.resource.handle)) {
                idr_remove(&client->resource_idr, e->r.resource.handle);
                /* Drop the idr's reference */
                client_put(client);
        }
        spin_unlock_irqrestore(&client->lock, flags);

        rsp->type = FW_CDEV_EVENT_RESPONSE;
        rsp->rcode = rcode;

        /*
         * In the case that sizeof(*rsp) doesn't align with the position of the
         * data, and the read is short, preserve an extra copy of the data
         * to stay compatible with a pre-2.6.27 bug.  Since the bug is harmless
         * for short reads and some apps depended on it, this is both safe
         * and prudent for compatibility.
         */
        if (rsp->length <= sizeof(*rsp) - offsetof(typeof(*rsp), data))
                queue_event(client, &e->event, rsp, sizeof(*rsp),
                            rsp->data, rsp->length);
        else
                queue_event(client, &e->event, rsp, sizeof(*rsp) + rsp->length,
                            NULL, 0);

        /* Drop the transaction callback's reference */
        client_put(client);
}

static int init_request(struct client *client,
                        struct fw_cdev_send_request *request,
                        int destination_id, int speed)
{
        struct outbound_transaction_event *e;
        int ret;

        if (request->tcode != TCODE_STREAM_DATA &&
            (request->length > 4096 || request->length > 512 << speed))
                return -EIO;

        e = kmalloc(sizeof(*e) + request->length, GFP_KERNEL);
        if (e == NULL)
                return -ENOMEM;

        e->client = client;
        e->response.length = request->length;
        e->response.closure = request->closure;

        if (request->data &&
            copy_from_user(e->response.data,
                           u64_to_uptr(request->data), request->length)) {
                ret = -EFAULT;
                goto failed;
        }

        e->r.resource.release = release_transaction;
        ret = add_client_resource(client, &e->r.resource, GFP_KERNEL);
        if (ret < 0)
                goto failed;

        /* Get a reference for the transaction callback */
        client_get(client);

        fw_send_request(client->device->card, &e->r.transaction,
                        request->tcode, destination_id, request->generation,
                        speed, request->offset, e->response.data,
                        request->length, complete_transaction, e);
        return 0;

 failed:
        kfree(e);

        return ret;
}

static int ioctl_send_request(struct client *client, union ioctl_arg *arg)
{
        switch (arg->send_request.tcode) {
        case TCODE_WRITE_QUADLET_REQUEST:
        case TCODE_WRITE_BLOCK_REQUEST:
        case TCODE_READ_QUADLET_REQUEST:
        case TCODE_READ_BLOCK_REQUEST:
        case TCODE_LOCK_MASK_SWAP:
        case TCODE_LOCK_COMPARE_SWAP:
        case TCODE_LOCK_FETCH_ADD:
        case TCODE_LOCK_LITTLE_ADD:
        case TCODE_LOCK_BOUNDED_ADD:
        case TCODE_LOCK_WRAP_ADD:
        case TCODE_LOCK_VENDOR_DEPENDENT:
                break;
        default:
                return -EINVAL;
        }

        return init_request(client, &arg->send_request, client->device->node_id,
                            client->device->max_speed);
}

static inline bool is_fcp_request(struct fw_request *request)
{
        return request == NULL;
}

static void release_request(struct client *client,
                            struct client_resource *resource)
{
        struct inbound_transaction_resource *r = container_of(resource,
                        struct inbound_transaction_resource, resource);

        if (is_fcp_request(r->request))
                kfree(r->data);
        else
                fw_send_response(client->device->card, r->request,
                                 RCODE_CONFLICT_ERROR);
        kfree(r);
}

static void handle_request(struct fw_card *card, struct fw_request *request,
                           int tcode, int destination, int source,
                           int generation, int speed,
                           unsigned long long offset,
                           void *payload, size_t length, void *callback_data)
{
        struct address_handler_resource *handler = callback_data;
        struct inbound_transaction_resource *r;
        struct inbound_transaction_event *e;
        void *fcp_frame = NULL;
        int ret;

        r = kmalloc(sizeof(*r), GFP_ATOMIC);
        e = kmalloc(sizeof(*e), GFP_ATOMIC);
        if (r == NULL || e == NULL)
                goto failed;

        r->request = request;
        r->data    = payload;
        r->length  = length;

        if (is_fcp_request(request)) {
                /*
                 * FIXME: Let core-transaction.c manage a
                 * single reference-counted copy?
                 */
                fcp_frame = kmemdup(payload, length, GFP_ATOMIC);
                if (fcp_frame == NULL)
                        goto failed;

                r->data = fcp_frame;
        }

        r->resource.release = release_request;
        ret = add_client_resource(handler->client, &r->resource, GFP_ATOMIC);
        if (ret < 0)
                goto failed;

        e->request.type    = FW_CDEV_EVENT_REQUEST;
        e->request.tcode   = tcode;
        e->request.offset  = offset;
        e->request.length  = length;
        e->request.handle  = r->resource.handle;
        e->request.closure = handler->closure;

        queue_event(handler->client, &e->event,
                    &e->request, sizeof(e->request), r->data, length);
        return;

 failed:
        kfree(r);
        kfree(e);
        kfree(fcp_frame);

        if (!is_fcp_request(request))
                fw_send_response(card, request, RCODE_CONFLICT_ERROR);
}

static void release_address_handler(struct client *client,
                                    struct client_resource *resource)
{
        struct address_handler_resource *r =
            container_of(resource, struct address_handler_resource, resource);

        fw_core_remove_address_handler(&r->handler);
        kfree(r);
}

static int ioctl_allocate(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_allocate *a = &arg->allocate;
        struct address_handler_resource *r;
        struct fw_address_region region;
        int ret;

        r = kmalloc(sizeof(*r), GFP_KERNEL);
        if (r == NULL)
                return -ENOMEM;

        region.start = a->offset;
        region.end   = a->offset + a->length;
        r->handler.length           = a->length;
        r->handler.address_callback = handle_request;
        r->handler.callback_data    = r;
        r->closure   = a->closure;
        r->client    = client;

        ret = fw_core_add_address_handler(&r->handler, &region);
        if (ret < 0) {
                kfree(r);
                return ret;
        }

        r->resource.release = release_address_handler;
        ret = add_client_resource(client, &r->resource, GFP_KERNEL);
        if (ret < 0) {
                release_address_handler(client, &r->resource);
                return ret;
        }
        a->handle = r->resource.handle;

        return 0;
}

static int ioctl_deallocate(struct client *client, union ioctl_arg *arg)
{
        return release_client_resource(client, arg->deallocate.handle,
                                       release_address_handler, NULL);
}

static int ioctl_send_response(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_send_response *a = &arg->send_response;
        struct client_resource *resource;
        struct inbound_transaction_resource *r;
        int ret = 0;

        if (release_client_resource(client, a->handle,
                                    release_request, &resource) < 0)
                return -EINVAL;

        r = container_of(resource, struct inbound_transaction_resource,
                         resource);
        if (is_fcp_request(r->request))
                goto out;

        if (a->length < r->length)
                r->length = a->length;
        if (copy_from_user(r->data, u64_to_uptr(a->data), r->length)) {
                ret = -EFAULT;
                kfree(r->request);
                goto out;
        }
        fw_send_response(client->device->card, r->request, a->rcode);
 out:
        kfree(r);

        return ret;
}

static int ioctl_initiate_bus_reset(struct client *client, union ioctl_arg *arg)
{
        return fw_core_initiate_bus_reset(client->device->card,
                        arg->initiate_bus_reset.type == FW_CDEV_SHORT_RESET);
}

static void release_descriptor(struct client *client,
                               struct client_resource *resource)
{
        struct descriptor_resource *r =
                container_of(resource, struct descriptor_resource, resource);

        fw_core_remove_descriptor(&r->descriptor);
        kfree(r);
}

static int ioctl_add_descriptor(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_add_descriptor *a = &arg->add_descriptor;
        struct descriptor_resource *r;
        int ret;

        /* Access policy: Allow this ioctl only on local nodes' device files. */
        if (!client->device->is_local)
                return -ENOSYS;

        if (a->length > 256)
                return -EINVAL;

        r = kmalloc(sizeof(*r) + a->length * 4, GFP_KERNEL);
        if (r == NULL)
                return -ENOMEM;

        if (copy_from_user(r->data, u64_to_uptr(a->data), a->length * 4)) {
                ret = -EFAULT;
                goto failed;
        }

        r->descriptor.length    = a->length;
        r->descriptor.immediate = a->immediate;
        r->descriptor.key       = a->key;
        r->descriptor.data      = r->data;

        ret = fw_core_add_descriptor(&r->descriptor);
        if (ret < 0)
                goto failed;

        r->resource.release = release_descriptor;
        ret = add_client_resource(client, &r->resource, GFP_KERNEL);
        if (ret < 0) {
                fw_core_remove_descriptor(&r->descriptor);
                goto failed;
        }
        a->handle = r->resource.handle;

        return 0;
 failed:
        kfree(r);

        return ret;
}

static int ioctl_remove_descriptor(struct client *client, union ioctl_arg *arg)
{
        return release_client_resource(client, arg->remove_descriptor.handle,
                                       release_descriptor, NULL);
}

static void iso_callback(struct fw_iso_context *context, u32 cycle,
                         size_t header_length, void *header, void *data)
{
        struct client *client = data;
        struct iso_interrupt_event *e;

        e = kzalloc(sizeof(*e) + header_length, GFP_ATOMIC);
        if (e == NULL)
                return;

        e->interrupt.type      = FW_CDEV_EVENT_ISO_INTERRUPT;
        e->interrupt.closure   = client->iso_closure;
        e->interrupt.cycle     = cycle;
        e->interrupt.header_length = header_length;
        memcpy(e->interrupt.header, header, header_length);
        queue_event(client, &e->event, &e->interrupt,
                    sizeof(e->interrupt) + header_length, NULL, 0);
}

static int ioctl_create_iso_context(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_create_iso_context *a = &arg->create_iso_context;
        struct fw_iso_context *context;

        /* We only support one context at this time. */
        if (client->iso_context != NULL)
                return -EBUSY;

        if (a->channel > 63)
                return -EINVAL;

        switch (a->type) {
        case FW_ISO_CONTEXT_RECEIVE:
                if (a->header_size < 4 || (a->header_size & 3))
                        return -EINVAL;
                break;

        case FW_ISO_CONTEXT_TRANSMIT:
                if (a->speed > SCODE_3200)
                        return -EINVAL;
                break;

        default:
                return -EINVAL;
        }

        context = fw_iso_context_create(client->device->card, a->type,
                                        a->channel, a->speed, a->header_size,
                                        iso_callback, client);
        if (IS_ERR(context))
                return PTR_ERR(context);

        client->iso_closure = a->closure;
        client->iso_context = context;

        /* We only support one context at this time. */
        a->handle = 0;

        return 0;
}

/* Macros for decoding the iso packet control header. */
#define GET_PAYLOAD_LENGTH(v)   ((v) & 0xffff)
#define GET_INTERRUPT(v)        (((v) >> 16) & 0x01)
#define GET_SKIP(v)             (((v) >> 17) & 0x01)
#define GET_TAG(v)              (((v) >> 18) & 0x03)
#define GET_SY(v)               (((v) >> 20) & 0x0f)
#define GET_HEADER_LENGTH(v)    (((v) >> 24) & 0xff)

static int ioctl_queue_iso(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_queue_iso *a = &arg->queue_iso;
        struct fw_cdev_iso_packet __user *p, *end, *next;
        struct fw_iso_context *ctx = client->iso_context;
        unsigned long payload, buffer_end, header_length;
        u32 control;
        int count;
        struct {
                struct fw_iso_packet packet;
                u8 header[256];
        } u;

        if (ctx == NULL || a->handle != 0)
                return -EINVAL;

        /*
         * If the user passes a non-NULL data pointer, has mmap()'ed
         * the iso buffer, and the pointer points inside the buffer,
         * we setup the payload pointers accordingly.  Otherwise we
         * set them both to 0, which will still let packets with
         * payload_length == 0 through.  In other words, if no packets
         * use the indirect payload, the iso buffer need not be mapped
         * and the a->data pointer is ignored.
         */

        payload = (unsigned long)a->data - client->vm_start;
        buffer_end = client->buffer.page_count << PAGE_SHIFT;
        if (a->data == 0 || client->buffer.pages == NULL ||
            payload >= buffer_end) {
                payload = 0;
                buffer_end = 0;
        }

        p = (struct fw_cdev_iso_packet __user *)u64_to_uptr(a->packets);

        if (!access_ok(VERIFY_READ, p, a->size))
                return -EFAULT;

        end = (void __user *)p + a->size;
        count = 0;
        while (p < end) {
                if (get_user(control, &p->control))
                        return -EFAULT;
                u.packet.payload_length = GET_PAYLOAD_LENGTH(control);
                u.packet.interrupt = GET_INTERRUPT(control);
                u.packet.skip = GET_SKIP(control);
                u.packet.tag = GET_TAG(control);
                u.packet.sy = GET_SY(control);
                u.packet.header_length = GET_HEADER_LENGTH(control);

                if (ctx->type == FW_ISO_CONTEXT_TRANSMIT) {
                        if (u.packet.header_length % 4 != 0)
                                return -EINVAL;
                        header_length = u.packet.header_length;
                } else {
                        /*
                         * We require that header_length is a multiple of
                         * the fixed header size, ctx->header_size.
                         */
                        if (ctx->header_size == 0) {
                                if (u.packet.header_length > 0)
                                        return -EINVAL;
                        } else if (u.packet.header_length == 0 ||
                                   u.packet.header_length % ctx->header_size != 0) {
                                return -EINVAL;
                        }
                        header_length = 0;
                }

                next = (struct fw_cdev_iso_packet __user *)
                        &p->header[header_length / 4];
                if (next > end)
                        return -EINVAL;
                if (__copy_from_user
                    (u.packet.header, p->header, header_length))
                        return -EFAULT;
                if (u.packet.skip && ctx->type == FW_ISO_CONTEXT_TRANSMIT &&
                    u.packet.header_length + u.packet.payload_length > 0)
                        return -EINVAL;
                if (payload + u.packet.payload_length > buffer_end)
                        return -EINVAL;

                if (fw_iso_context_queue(ctx, &u.packet,
                                         &client->buffer, payload))
                        break;

                p = next;
                payload += u.packet.payload_length;
                count++;
        }

        a->size    -= uptr_to_u64(p) - a->packets;
        a->packets  = uptr_to_u64(p);
        a->data     = client->vm_start + payload;

        return count;
}

static int ioctl_start_iso(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_start_iso *a = &arg->start_iso;

        if (client->iso_context == NULL || a->handle != 0)
                return -EINVAL;

        if (client->iso_context->type == FW_ISO_CONTEXT_RECEIVE &&
            (a->tags == 0 || a->tags > 15 || a->sync > 15))
                return -EINVAL;

        return fw_iso_context_start(client->iso_context,
                                    a->cycle, a->sync, a->tags);
}

static int ioctl_stop_iso(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_stop_iso *a = &arg->stop_iso;

        if (client->iso_context == NULL || a->handle != 0)
                return -EINVAL;

        return fw_iso_context_stop(client->iso_context);
}

static int ioctl_get_cycle_timer2(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_get_cycle_timer2 *a = &arg->get_cycle_timer2;
        struct fw_card *card = client->device->card;
        struct timespec ts = {0, 0};
        u32 cycle_time;
        int ret = 0;

        local_irq_disable();

        cycle_time = card->driver->get_cycle_time(card);

        switch (a->clk_id) {
        case CLOCK_REALTIME:      getnstimeofday(&ts);                   break;
        case CLOCK_MONOTONIC:     do_posix_clock_monotonic_gettime(&ts); break;
        case CLOCK_MONOTONIC_RAW: getrawmonotonic(&ts);                  break;
        default:
                ret = -EINVAL;
        }

        local_irq_enable();

        a->tv_sec      = ts.tv_sec;
        a->tv_nsec     = ts.tv_nsec;
        a->cycle_timer = cycle_time;

        return ret;
}

static int ioctl_get_cycle_timer(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_get_cycle_timer *a = &arg->get_cycle_timer;
        struct fw_cdev_get_cycle_timer2 ct2;

        ct2.clk_id = CLOCK_REALTIME;
        ioctl_get_cycle_timer2(client, (union ioctl_arg *)&ct2);

        a->local_time = ct2.tv_sec * USEC_PER_SEC + ct2.tv_nsec / NSEC_PER_USEC;
        a->cycle_timer = ct2.cycle_timer;

        return 0;
}

static void iso_resource_work(struct work_struct *work)
{
        struct iso_resource_event *e;
        struct iso_resource *r =
                        container_of(work, struct iso_resource, work.work);
        struct client *client = r->client;
        int generation, channel, bandwidth, todo;
        bool skip, free, success;

        spin_lock_irq(&client->lock);
        generation = client->device->generation;
        todo = r->todo;
        /* Allow 1000ms grace period for other reallocations. */
        if (todo == ISO_RES_ALLOC &&
            time_is_after_jiffies(client->device->card->reset_jiffies + HZ)) {
                schedule_iso_resource(r, DIV_ROUND_UP(HZ, 3));
                skip = true;
        } else {
                /* We could be called twice within the same generation. */
                skip = todo == ISO_RES_REALLOC &&
                       r->generation == generation;
        }
        free = todo == ISO_RES_DEALLOC ||
               todo == ISO_RES_ALLOC_ONCE ||
               todo == ISO_RES_DEALLOC_ONCE;
        r->generation = generation;
        spin_unlock_irq(&client->lock);

        if (skip)
                goto out;

        bandwidth = r->bandwidth;

        fw_iso_resource_manage(client->device->card, generation,
                        r->channels, &channel, &bandwidth,
                        todo == ISO_RES_ALLOC ||
                        todo == ISO_RES_REALLOC ||
                        todo == ISO_RES_ALLOC_ONCE,
                        r->transaction_data);
        /*
         * Is this generation outdated already?  As long as this resource sticks
         * in the idr, it will be scheduled again for a newer generation or at
         * shutdown.
         */
        if (channel == -EAGAIN &&
            (todo == ISO_RES_ALLOC || todo == ISO_RES_REALLOC))
                goto out;

        success = channel >= 0 || bandwidth > 0;

        spin_lock_irq(&client->lock);
        /*
         * Transit from allocation to reallocation, except if the client
         * requested deallocation in the meantime.
         */
        if (r->todo == ISO_RES_ALLOC)
                r->todo = ISO_RES_REALLOC;
        /*
         * Allocation or reallocation failure?  Pull this resource out of the
         * idr and prepare for deletion, unless the client is shutting down.
         */
        if (r->todo == ISO_RES_REALLOC && !success &&
            !client->in_shutdown &&
            idr_find(&client->resource_idr, r->resource.handle)) {
                idr_remove(&client->resource_idr, r->resource.handle);
                client_put(client);
                free = true;
        }
        spin_unlock_irq(&client->lock);

        if (todo == ISO_RES_ALLOC && channel >= 0)
                r->channels = 1ULL << channel;

        if (todo == ISO_RES_REALLOC && success)
                goto out;

        if (todo == ISO_RES_ALLOC || todo == ISO_RES_ALLOC_ONCE) {
                e = r->e_alloc;
                r->e_alloc = NULL;
        } else {
                e = r->e_dealloc;
                r->e_dealloc = NULL;
        }
        e->iso_resource.handle    = r->resource.handle;
        e->iso_resource.channel   = channel;
        e->iso_resource.bandwidth = bandwidth;

        queue_event(client, &e->event,
                    &e->iso_resource, sizeof(e->iso_resource), NULL, 0);

        if (free) {
                cancel_delayed_work(&r->work);
                kfree(r->e_alloc);
                kfree(r->e_dealloc);
                kfree(r);
        }
 out:
        client_put(client);
}

static void release_iso_resource(struct client *client,
                                 struct client_resource *resource)
{
        struct iso_resource *r =
                container_of(resource, struct iso_resource, resource);

        spin_lock_irq(&client->lock);
        r->todo = ISO_RES_DEALLOC;
        schedule_iso_resource(r, 0);
        spin_unlock_irq(&client->lock);
}

static int init_iso_resource(struct client *client,
                struct fw_cdev_allocate_iso_resource *request, int todo)
{
        struct iso_resource_event *e1, *e2;
        struct iso_resource *r;
        int ret;

        if ((request->channels == 0 && request->bandwidth == 0) ||
            request->bandwidth > BANDWIDTH_AVAILABLE_INITIAL ||
            request->bandwidth < 0)
                return -EINVAL;

        r  = kmalloc(sizeof(*r), GFP_KERNEL);
        e1 = kmalloc(sizeof(*e1), GFP_KERNEL);
        e2 = kmalloc(sizeof(*e2), GFP_KERNEL);
        if (r == NULL || e1 == NULL || e2 == NULL) {
                ret = -ENOMEM;
                goto fail;
        }

        INIT_DELAYED_WORK(&r->work, iso_resource_work);
        r->client       = client;
        r->todo         = todo;
        r->generation   = -1;
        r->channels     = request->channels;
        r->bandwidth    = request->bandwidth;
        r->e_alloc      = e1;
        r->e_dealloc    = e2;

        e1->iso_resource.closure = request->closure;
        e1->iso_resource.type    = FW_CDEV_EVENT_ISO_RESOURCE_ALLOCATED;
        e2->iso_resource.closure = request->closure;
        e2->iso_resource.type    = FW_CDEV_EVENT_ISO_RESOURCE_DEALLOCATED;

        if (todo == ISO_RES_ALLOC) {
                r->resource.release = release_iso_resource;
                ret = add_client_resource(client, &r->resource, GFP_KERNEL);
                if (ret < 0)
                        goto fail;
        } else {
                r->resource.release = NULL;
                r->resource.handle = -1;
                schedule_iso_resource(r, 0);
        }
        request->handle = r->resource.handle;

        return 0;
 fail:
        kfree(r);
        kfree(e1);
        kfree(e2);

        return ret;
}

static int ioctl_allocate_iso_resource(struct client *client,
                                       union ioctl_arg *arg)
{
        return init_iso_resource(client,
                        &arg->allocate_iso_resource, ISO_RES_ALLOC);
}

static int ioctl_deallocate_iso_resource(struct client *client,
                                         union ioctl_arg *arg)
{
        return release_client_resource(client,
                        arg->deallocate.handle, release_iso_resource, NULL);
}

static int ioctl_allocate_iso_resource_once(struct client *client,
                                            union ioctl_arg *arg)
{
        return init_iso_resource(client,
                        &arg->allocate_iso_resource, ISO_RES_ALLOC_ONCE);
}

static int ioctl_deallocate_iso_resource_once(struct client *client,
                                              union ioctl_arg *arg)
{
        return init_iso_resource(client,
                        &arg->allocate_iso_resource, ISO_RES_DEALLOC_ONCE);
}

/*
 * Returns a speed code:  Maximum speed to or from this device,
 * limited by the device's link speed, the local node's link speed,
 * and all PHY port speeds between the two links.
 */
static int ioctl_get_speed(struct client *client, union ioctl_arg *arg)
{
        return client->device->max_speed;
}

static int ioctl_send_broadcast_request(struct client *client,
                                        union ioctl_arg *arg)
{
        struct fw_cdev_send_request *a = &arg->send_request;

        switch (a->tcode) {
        case TCODE_WRITE_QUADLET_REQUEST:
        case TCODE_WRITE_BLOCK_REQUEST:
                break;
        default:
                return -EINVAL;
        }

        /* Security policy: Only allow accesses to Units Space. */
        if (a->offset < CSR_REGISTER_BASE + CSR_CONFIG_ROM_END)
                return -EACCES;

        return init_request(client, a, LOCAL_BUS | 0x3f, SCODE_100);
}

static int ioctl_send_stream_packet(struct client *client, union ioctl_arg *arg)
{
        struct fw_cdev_send_stream_packet *a = &arg->send_stream_packet;
        struct fw_cdev_send_request request;
        int dest;

        if (a->speed > client->device->card->link_speed ||
            a->length > 1024 << a->speed)
                return -EIO;

        if (a->tag > 3 || a->channel > 63 || a->sy > 15)
                return -EINVAL;

        dest = fw_stream_packet_destination_id(a->tag, a->channel, a->sy);
        request.tcode           = TCODE_STREAM_DATA;
        request.length          = a->length;
        request.closure         = a->closure;
        request.data            = a->data;
        request.generation      = a->generation;

        return init_request(client, &request, dest, a->speed);
}

static int (* const ioctl_handlers[])(struct client *, union ioctl_arg *) = {
        ioctl_get_info,
        ioctl_send_request,
        ioctl_allocate,
        ioctl_deallocate,
        ioctl_send_response,
        ioctl_initiate_bus_reset,
        ioctl_add_descriptor,
        ioctl_remove_descriptor,
        ioctl_create_iso_context,
        ioctl_queue_iso,
        ioctl_start_iso,
        ioctl_stop_iso,
        ioctl_get_cycle_timer,
        ioctl_allocate_iso_resource,
        ioctl_deallocate_iso_resource,
        ioctl_allocate_iso_resource_once,
        ioctl_deallocate_iso_resource_once,
        ioctl_get_speed,
        ioctl_send_broadcast_request,
        ioctl_send_stream_packet,
        ioctl_get_cycle_timer2,
};

static int dispatch_ioctl(struct client *client,
                          unsigned int cmd, void __user *arg)
{
        union ioctl_arg buffer;
        int ret;

        if (fw_device_is_shutdown(client->device))
                return -ENODEV;

        if (_IOC_TYPE(cmd) != '#' ||
            _IOC_NR(cmd) >= ARRAY_SIZE(ioctl_handlers) ||
            _IOC_SIZE(cmd) > sizeof(buffer))
                return -EINVAL;

        if (_IOC_DIR(cmd) == _IOC_READ)
                memset(&buffer, 0, _IOC_SIZE(cmd));

        if (_IOC_DIR(cmd) & _IOC_WRITE)
                if (copy_from_user(&buffer, arg, _IOC_SIZE(cmd)))
                        return -EFAULT;

        ret = ioctl_handlers[_IOC_NR(cmd)](client, &buffer);
        if (ret < 0)
                return ret;

        if (_IOC_DIR(cmd) & _IOC_READ)
                if (copy_to_user(arg, &buffer, _IOC_SIZE(cmd)))
                        return -EFAULT;

        return ret;
}

static long fw_device_op_ioctl(struct file *file,
                               unsigned int cmd, unsigned long arg)
{
        return dispatch_ioctl(file->private_data, cmd, (void __user *)arg);
}

#ifdef CONFIG_COMPAT
static long fw_device_op_compat_ioctl(struct file *file,
                                      unsigned int cmd, unsigned long arg)
{
        return dispatch_ioctl(file->private_data, cmd, compat_ptr(arg));
}
#endif

static int fw_device_op_mmap(struct file *file, struct vm_area_struct *vma)
{
        struct client *client = file->private_data;
        enum dma_data_direction direction;
        unsigned long size;
        int page_count, ret;

        if (fw_device_is_shutdown(client->device))
                return -ENODEV;

        /* FIXME: We could support multiple buffers, but we don't. */
        if (client->buffer.pages != NULL)
                return -EBUSY;

        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        if (vma->vm_start & ~PAGE_MASK)
                return -EINVAL;

        client->vm_start = vma->vm_start;
        size = vma->vm_end - vma->vm_start;
        page_count = size >> PAGE_SHIFT;
        if (size & ~PAGE_MASK)
                return -EINVAL;

        if (vma->vm_flags & VM_WRITE)
                direction = DMA_TO_DEVICE;
        else
                direction = DMA_FROM_DEVICE;

        ret = fw_iso_buffer_init(&client->buffer, client->device->card,
                                 page_count, direction);
        if (ret < 0)
                return ret;

        ret = fw_iso_buffer_map(&client->buffer, vma);
        if (ret < 0)
                fw_iso_buffer_destroy(&client->buffer, client->device->card);

        return ret;
}

static int shutdown_resource(int id, void *p, void *data)
{
        struct client_resource *resource = p;
        struct client *client = data;

        resource->release(client, resource);
        client_put(client);

        return 0;
}

static int fw_device_op_release(struct inode *inode, struct file *file)
{
        struct client *client = file->private_data;
        struct event *event, *next_event;

        mutex_lock(&client->device->client_list_mutex);
        list_del(&client->link);
        mutex_unlock(&client->device->client_list_mutex);

        if (client->iso_context)
                fw_iso_context_destroy(client->iso_context);

        if (client->buffer.pages)
                fw_iso_buffer_destroy(&client->buffer, client->device->card);

        /* Freeze client->resource_idr and client->event_list */
        spin_lock_irq(&client->lock);
        client->in_shutdown = true;
        spin_unlock_irq(&client->lock);

        idr_for_each(&client->resource_idr, shutdown_resource, client);
        idr_remove_all(&client->resource_idr);
        idr_destroy(&client->resource_idr);

        list_for_each_entry_safe(event, next_event, &client->event_list, link)
                kfree(event);

        client_put(client);

        return 0;
}

static unsigned int fw_device_op_poll(struct file *file, poll_table * pt)
{
        struct client *client = file->private_data;
        unsigned int mask = 0;

        poll_wait(file, &client->wait, pt);

        if (fw_device_is_shutdown(client->device))
                mask |= POLLHUP | POLLERR;
        if (!list_empty(&client->event_list))
                mask |= POLLIN | POLLRDNORM;

        return mask;
}

const struct file_operations fw_device_ops = {
        .owner          = THIS_MODULE,
        .llseek         = no_llseek,
        .open           = fw_device_op_open,
        .read           = fw_device_op_read,
        .unlocked_ioctl = fw_device_op_ioctl,
        .mmap           = fw_device_op_mmap,
        .release        = fw_device_op_release,
        .poll           = fw_device_op_poll,
#ifdef CONFIG_COMPAT
        .compat_ioctl   = fw_device_op_compat_ioctl,
#endif
};