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

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

	client->device = 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);