x86: fix bootup crash in native_read_tsc()

[wrt350n-kernel.git] / drivers / firewire / fw-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/module.h>
#include <linux/kernel.h>
#include <linux/wait.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/vmalloc.h>
#include <linux/poll.h>
#include <linux/preempt.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/idr.h>
#include <linux/compat.h>
#include <linux/firewire-cdev.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include "fw-transaction.h"
#include "fw-topology.h"
#include "fw-device.h"

struct client;
struct client_resource {
        struct list_head link;
        void (*release)(struct client *client, struct client_resource *r);
        u32 handle;
};

/*
 * dequeue_event() just kfree()'s the event, so the event has to be
 * the first field in the struct.
 */

struct event {
        struct { void *data; size_t size; } v[2];
        struct list_head link;
};

struct bus_reset {
        struct event event;
        struct fw_cdev_event_bus_reset reset;
};

struct response {
        struct event event;
        struct fw_transaction transaction;
        struct client *client;
        struct client_resource resource;
        struct fw_cdev_event_response response;
};

struct iso_interrupt {
        struct event event;
        struct fw_cdev_event_iso_interrupt interrupt;
};

struct client {
        u32 version;
        struct fw_device *device;
        spinlock_t lock;
        u32 resource_handle;
        struct list_head resource_list;
        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;
};

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;
        unsigned long flags;

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

        client = kzalloc(sizeof(*client), GFP_KERNEL);
        if (client == NULL)
                return -ENOMEM;

        client->device = fw_device_get(device);
        INIT_LIST_HEAD(&client->event_list);
        INIT_LIST_HEAD(&client->resource_list);
        spin_lock_init(&client->lock);
        init_waitqueue_head(&client->wait);

        file->private_data = client;

        spin_lock_irqsave(&device->card->lock, flags);
        list_add_tail(&client->link, &device->client_list);
        spin_unlock_irqrestore(&device->card->lock, flags);

        return 0;
}

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);
        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)
{
        unsigned long flags;
        struct event *event;
        size_t size, total;
        int i, retval;

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

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

        spin_lock_irqsave(&client->lock, flags);
        event = container_of(client->event_list.next, struct event, link);
        list_del(&event->link);
        spin_unlock_irqrestore(&client->lock, flags);

        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)) {
                        retval = -EFAULT;
                        goto out;
                }
                total += size;
        }
        retval = total;

 out:
        kfree(event);

        return retval;
}

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;

        event->closure       = client->bus_reset_closure;
        event->type          = FW_CDEV_EVENT_BUS_RESET;
        event->generation    = client->device->generation;
        smp_rmb();           /* node_id must not be older than 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;
}

static void
for_each_client(struct fw_device *device,
                void (*callback)(struct client *client))
{
        struct fw_card *card = device->card;
        struct client *c;
        unsigned long flags;

        spin_lock_irqsave(&card->lock, flags);

        list_for_each_entry(c, &device->client_list, link)
                callback(c);

        spin_unlock_irqrestore(&card->lock, flags);
}

static void
queue_bus_reset_event(struct client *client)
{
        struct bus_reset *bus_reset;

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

        fill_bus_reset_event(&bus_reset->reset, client);

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

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);
}

static int ioctl_get_info(struct client *client, void *buffer)
{
        struct fw_cdev_get_info *get_info = buffer;
        struct fw_cdev_event_bus_reset bus_reset;

        client->version = get_info->version;
        get_info->version = FW_CDEV_VERSION;

        if (get_info->rom != 0) {
                void __user *uptr = u64_to_uptr(get_info->rom);
                size_t want = get_info->rom_length;
                size_t have = client->device->config_rom_length * 4;

                if (copy_to_user(uptr, client->device->config_rom,
                                 min(want, have)))
                        return -EFAULT;
        }
        get_info->rom_length = client->device->config_rom_length * 4;

        client->bus_reset_closure = get_info->bus_reset_closure;
        if (get_info->bus_reset != 0) {
                void __user *uptr = u64_to_uptr(get_info->bus_reset);

                fill_bus_reset_event(&bus_reset, client);
                if (copy_to_user(uptr, &bus_reset, sizeof(bus_reset)))
                        return -EFAULT;
        }

        get_info->card = client->device->card->index;

        return 0;
}

static void
add_client_resource(struct client *client, struct client_resource *resource)
{
        unsigned long flags;

        spin_lock_irqsave(&client->lock, flags);
        list_add_tail(&resource->link, &client->resource_list);
        resource->handle = client->resource_handle++;
        spin_unlock_irqrestore(&client->lock, flags);
}

static int
release_client_resource(struct client *client, u32 handle,
                        struct client_resource **resource)
{
        struct client_resource *r;
        unsigned long flags;

        spin_lock_irqsave(&client->lock, flags);
        list_for_each_entry(r, &client->resource_list, link) {
                if (r->handle == handle) {
                        list_del(&r->link);
                        break;
                }
        }
        spin_unlock_irqrestore(&client->lock, flags);

        if (&r->link == &client->resource_list)
                return -EINVAL;

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

        return 0;
}

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

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

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

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

        spin_lock_irqsave(&client->lock, flags);
        list_del(&response->resource.link);
        spin_unlock_irqrestore(&client->lock, flags);

        response->response.type   = FW_CDEV_EVENT_RESPONSE;
        response->response.rcode  = rcode;
        queue_event(client, &response->event,
                    &response->response, sizeof(response->response),
                    response->response.data, response->response.length);
}

static int ioctl_send_request(struct client *client, void *buffer)
{
        struct fw_device *device = client->device;
        struct fw_cdev_send_request *request = buffer;
        struct response *response;

        /* What is the biggest size we'll accept, really? */
        if (request->length > 4096)
                return -EINVAL;

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

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

        if (request->data &&
            copy_from_user(response->response.data,
                           u64_to_uptr(request->data), request->length)) {
                kfree(response);
                return -EFAULT;
        }

        response->resource.release = release_transaction;
        add_client_resource(client, &response->resource);

        fw_send_request(device->card, &response->transaction,
                        request->tcode & 0x1f,
                        device->node->node_id,
                        request->generation,
                        device->max_speed,
                        request->offset,
                        response->response.data, request->length,
                        complete_transaction, response);

        if (request->data)
                return sizeof(request) + request->length;
        else
                return sizeof(request);
}

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

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

struct request_event {
        struct event event;
        struct fw_cdev_event_request request;
};

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

        fw_send_response(client->device->card, request->request,
                         RCODE_CONFLICT_ERROR);
        kfree(request);
}

static void
handle_request(struct fw_card *card, struct fw_request *r,
               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 *handler = callback_data;
        struct request *request;
        struct request_event *e;
        struct client *client = handler->client;

        request = kmalloc(sizeof(*request), GFP_ATOMIC);
        e = kmalloc(sizeof(*e), GFP_ATOMIC);
        if (request == NULL || e == NULL) {
                kfree(request);
                kfree(e);
                fw_send_response(card, r, RCODE_CONFLICT_ERROR);
                return;
        }

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

        request->resource.release = release_request;
        add_client_resource(client, &request->resource);

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

        queue_event(client, &e->event,
                    &e->request, sizeof(e->request), payload, length);
}

static void
release_address_handler(struct client *client,
                        struct client_resource *resource)
{
        struct address_handler *handler =
                container_of(resource, struct address_handler, resource);

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

static int ioctl_allocate(struct client *client, void *buffer)
{
        struct fw_cdev_allocate *request = buffer;
        struct address_handler *handler;
        struct fw_address_region region;

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

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

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

        handler->resource.release = release_address_handler;
        add_client_resource(client, &handler->resource);
        request->handle = handler->resource.handle;

        return 0;
}

static int ioctl_deallocate(struct client *client, void *buffer)
{
        struct fw_cdev_deallocate *request = buffer;

        return release_client_resource(client, request->handle, NULL);
}

static int ioctl_send_response(struct client *client, void *buffer)
{
        struct fw_cdev_send_response *request = buffer;
        struct client_resource *resource;
        struct request *r;

        if (release_client_resource(client, request->handle, &resource) < 0)
                return -EINVAL;
        r = container_of(resource, struct request, resource);
        if (request->length < r->length)
                r->length = request->length;
        if (copy_from_user(r->data, u64_to_uptr(request->data), r->length))
                return -EFAULT;

        fw_send_response(client->device->card, r->request, request->rcode);
        kfree(r);

        return 0;
}

static int ioctl_initiate_bus_reset(struct client *client, void *buffer)
{
        struct fw_cdev_initiate_bus_reset *request = buffer;
        int short_reset;

        short_reset = (request->type == FW_CDEV_SHORT_RESET);

        return fw_core_initiate_bus_reset(client->device->card, short_reset);
}

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

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

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

static int ioctl_add_descriptor(struct client *client, void *buffer)
{
        struct fw_cdev_add_descriptor *request = buffer;
        struct descriptor *descriptor;
        int retval;

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

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

        if (copy_from_user(descriptor->data,
                           u64_to_uptr(request->data), request->length * 4)) {
                kfree(descriptor);
                return -EFAULT;
        }

        descriptor->d.length = request->length;
        descriptor->d.immediate = request->immediate;
        descriptor->d.key = request->key;
        descriptor->d.data = descriptor->data;

        retval = fw_core_add_descriptor(&descriptor->d);
        if (retval < 0) {
                kfree(descriptor);
                return retval;
        }

        descriptor->resource.release = release_descriptor;
        add_client_resource(client, &descriptor->resource);
        request->handle = descriptor->resource.handle;

        return 0;
}

static int ioctl_remove_descriptor(struct client *client, void *buffer)
{
        struct fw_cdev_remove_descriptor *request = buffer;

        return release_client_resource(client, request->handle, 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 *irq;

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

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

static int ioctl_create_iso_context(struct client *client, void *buffer)
{
        struct fw_cdev_create_iso_context *request = buffer;
        struct fw_iso_context *context;

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

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

                break;

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

                break;

        default:
                return -EINVAL;
        }

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

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

        /* We only support one context at this time. */
        request->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) & 0x02)
#define GET_SY(v)               (((v) >> 20) & 0x04)
#define GET_HEADER_LENGTH(v)    (((v) >> 24) & 0xff)

static int ioctl_queue_iso(struct client *client, void *buffer)
{
        struct fw_cdev_queue_iso *request = buffer;
        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 || request->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 request->data pointer is ignored.
         */

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

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

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

        end = (void __user *)p + request->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) {
                        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 % 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++;
        }

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

        return count;
}

static int ioctl_start_iso(struct client *client, void *buffer)
{
        struct fw_cdev_start_iso *request = buffer;

        if (request->handle != 0)
                return -EINVAL;
        if (client->iso_context->type == FW_ISO_CONTEXT_RECEIVE) {
                if (request->tags == 0 || request->tags > 15)
                        return -EINVAL;

                if (request->sync > 15)
                        return -EINVAL;
        }

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

static int ioctl_stop_iso(struct client *client, void *buffer)
{
        struct fw_cdev_stop_iso *request = buffer;

        if (request->handle != 0)
                return -EINVAL;

        return fw_iso_context_stop(client->iso_context);
}

static int ioctl_get_cycle_timer(struct client *client, void *buffer)
{
        struct fw_cdev_get_cycle_timer *request = buffer;
        struct fw_card *card = client->device->card;
        unsigned long long bus_time;
        struct timeval tv;
        unsigned long flags;

        preempt_disable();
        local_irq_save(flags);

        bus_time = card->driver->get_bus_time(card);
        do_gettimeofday(&tv);

        local_irq_restore(flags);
        preempt_enable();

        request->local_time = tv.tv_sec * 1000000ULL + tv.tv_usec;
        request->cycle_timer = bus_time & 0xffffffff;
        return 0;
}

static int (* const ioctl_handlers[])(struct client *client, void *buffer) = {
        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,
};

static int
dispatch_ioctl(struct client *client, unsigned int cmd, void __user *arg)
{
        char buffer[256];
        int retval;

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

        if (_IOC_DIR(cmd) & _IOC_WRITE) {
                if (_IOC_SIZE(cmd) > sizeof(buffer) ||
                    copy_from_user(buffer, arg, _IOC_SIZE(cmd)))
                        return -EFAULT;
        }

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

        if (_IOC_DIR(cmd) & _IOC_READ) {
                if (_IOC_SIZE(cmd) > sizeof(buffer) ||
                    copy_to_user(arg, buffer, _IOC_SIZE(cmd)))
                        return -EFAULT;
        }

        return 0;
}

static long
fw_device_op_ioctl(struct file *file,
                   unsigned int cmd, unsigned long arg)
{
        struct client *client = file->private_data;

        return dispatch_ioctl(client, cmd, (void __user *) arg);
}

#ifdef CONFIG_COMPAT
static long
fw_device_op_compat_ioctl(struct file *file,
                          unsigned int cmd, unsigned long arg)
{
        struct client *client = file->private_data;

        return dispatch_ioctl(client, 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, retval;

        /* 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;

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

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

        return retval;
}

static int fw_device_op_release(struct inode *inode, struct file *file)
{
        struct client *client = file->private_data;
        struct event *e, *next_e;
        struct client_resource *r, *next_r;
        unsigned long flags;

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

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

        list_for_each_entry_safe(r, next_r, &client->resource_list, link)
                r->release(client, r);

        /*
         * FIXME: We should wait for the async tasklets to stop
         * running before freeing the memory.
         */

        list_for_each_entry_safe(e, next_e, &client->event_list, link)
                kfree(e);

        spin_lock_irqsave(&client->device->card->lock, flags);
        list_del(&client->link);
        spin_unlock_irqrestore(&client->device->card->lock, flags);

        fw_device_put(client->device);
        kfree(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,
        .open           = fw_device_op_open,
        .read           = fw_device_op_read,
        .unlocked_ioctl = fw_device_op_ioctl,
        .poll           = fw_device_op_poll,
        .release        = fw_device_op_release,
        .mmap           = fw_device_op_mmap,

#ifdef CONFIG_COMPAT
        .compat_ioctl   = fw_device_op_compat_ioctl,
#endif
};