adb.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 913 行 · 第 1/2 页

	va_list list;
	int i, use_sreq;
	int rc;

	if ((adb_controller == NULL) || (adb_controller->send_request == NULL))
		return -ENXIO;
	if (nbytes < 1)
		return -EINVAL;
	if (req == NULL && (flags & ADBREQ_NOSEND))
		return -EINVAL;
	
	if (req == NULL) {
		if (test_and_set_bit(0,&adb_sreq_lock)) {
			printk("adb.c: Warning: contention on static request !\n");
			return -EPERM;
		}
		req = &adb_sreq;
		flags |= ADBREQ_SYNC;
		use_sreq = 1;
	} else
		use_sreq = 0;
	req->nbytes = nbytes+1;
	req->done = done;
	req->reply_expected = flags & ADBREQ_REPLY;
	req->data[0] = ADB_PACKET;
	va_start(list, nbytes);
	for (i = 0; i < nbytes; ++i)
		req->data[i+1] = va_arg(list, int);
	va_end(list);

	if (flags & ADBREQ_NOSEND)
		return 0;

	/* Synchronous requests send from the probe thread cause it to
	 * block. Beware that the "done" callback will be overriden !
	 */
	if ((flags & ADBREQ_SYNC) &&
	    (current->pid && adb_probe_task_pid &&
	    adb_probe_task_pid == current->pid)) {
		req->done = adb_probe_wakeup;
		rc = adb_controller->send_request(req, 0);
		if (rc || req->complete)
			goto bail;
		wait_for_completion(&adb_probe_task_comp);
		rc = 0;
		goto bail;
	}

	rc = adb_controller->send_request(req, flags & ADBREQ_SYNC);
bail:
	if (use_sreq)
		clear_bit(0, &adb_sreq_lock);

	return rc;
}

 /* Ultimately this should return the number of devices with
    the given default id.
    And it does it now ! Note: changed behaviour: This function
    will now register if default_id _and_ handler_id both match
    but handler_id can be left to 0 to match with default_id only.
    When handler_id is set, this function will try to adjust
    the handler_id id it doesn't match. */
int
adb_register(int default_id, int handler_id, struct adb_ids *ids,
	     void (*handler)(unsigned char *, int, struct pt_regs *, int))
{
	int i;

	down(&adb_handler_sem);
	ids->nids = 0;
	for (i = 1; i < 16; i++) {
		if ((adb_handler[i].original_address == default_id) &&
		    (!handler_id || (handler_id == adb_handler[i].handler_id) || 
		    try_handler_change(i, handler_id))) {
			if (adb_handler[i].handler != 0) {
				printk(KERN_ERR
				       "Two handlers for ADB device %d\n",
				       default_id);
				continue;
			}
			write_lock_irq(&adb_handler_lock);
			adb_handler[i].handler = handler;
			write_unlock_irq(&adb_handler_lock);
			ids->id[ids->nids++] = i;
		}
	}
	up(&adb_handler_sem);
	return ids->nids;
}

int
adb_unregister(int index)
{
	int ret = -ENODEV;

	down(&adb_handler_sem);
	write_lock_irq(&adb_handler_lock);
	if (adb_handler[index].handler) {
		while(adb_handler[index].busy) {
			write_unlock_irq(&adb_handler_lock);
			yield();
			write_lock_irq(&adb_handler_lock);
		}
		ret = 0;
		adb_handler[index].handler = NULL;
	}
	write_unlock_irq(&adb_handler_lock);
	up(&adb_handler_sem);
	return ret;
}

void
adb_input(unsigned char *buf, int nb, struct pt_regs *regs, int autopoll)
{
	int i, id;
	static int dump_adb_input = 0;
	unsigned long flags;
	
	void (*handler)(unsigned char *, int, struct pt_regs *, int);

	/* We skip keystrokes and mouse moves when the sleep process
	 * has been started. We stop autopoll, but this is another security
	 */
	if (adb_got_sleep)
		return;
		
	id = buf[0] >> 4;
	if (dump_adb_input) {
		printk(KERN_INFO "adb packet: ");
		for (i = 0; i < nb; ++i)
			printk(" %x", buf[i]);
		printk(", id = %d\n", id);
	}
	write_lock_irqsave(&adb_handler_lock, flags);
	handler = adb_handler[id].handler;
	if (handler != NULL)
		adb_handler[id].busy = 1;
	write_unlock_irqrestore(&adb_handler_lock, flags);
	if (handler != NULL) {
		(*handler)(buf, nb, regs, autopoll);
		wmb();
		adb_handler[id].busy = 0;
	}
		
}

/* Try to change handler to new_id. Will return 1 if successful. */
static int try_handler_change(int address, int new_id)
{
	struct adb_request req;

	if (adb_handler[address].handler_id == new_id)
	    return 1;
	adb_request(&req, NULL, ADBREQ_SYNC, 3,
	    ADB_WRITEREG(address, 3), address | 0x20, new_id);
	adb_request(&req, NULL, ADBREQ_SYNC | ADBREQ_REPLY, 1,
	    ADB_READREG(address, 3));
	if (req.reply_len < 2)
	    return 0;
	if (req.reply[2] != new_id)
	    return 0;
	adb_handler[address].handler_id = req.reply[2];

	return 1;
}

int
adb_try_handler_change(int address, int new_id)
{
	int ret;

	down(&adb_handler_sem);
	ret = try_handler_change(address, new_id);
	up(&adb_handler_sem);
	return ret;
}

int
adb_get_infos(int address, int *original_address, int *handler_id)
{
	down(&adb_handler_sem);
	*original_address = adb_handler[address].original_address;
	*handler_id = adb_handler[address].handler_id;
	up(&adb_handler_sem);

	return (*original_address != 0);
}


/*
 * /dev/adb device driver.
 */

#define ADB_MAJOR	56	/* major number for /dev/adb */

struct adbdev_state {
	spinlock_t	lock;
	atomic_t	n_pending;
	struct adb_request *completed;
  	wait_queue_head_t wait_queue;
	int		inuse;
};

static void adb_write_done(struct adb_request *req)
{
	struct adbdev_state *state = (struct adbdev_state *) req->arg;
	unsigned long flags;

	if (!req->complete) {
		req->reply_len = 0;
		req->complete = 1;
	}
	spin_lock_irqsave(&state->lock, flags);
	atomic_dec(&state->n_pending);
	if (!state->inuse) {
		kfree(req);
		if (atomic_read(&state->n_pending) == 0) {
			spin_unlock_irqrestore(&state->lock, flags);
			kfree(state);
			return;
		}
	} else {
		struct adb_request **ap = &state->completed;
		while (*ap != NULL)
			ap = &(*ap)->next;
		req->next = NULL;
		*ap = req;
		wake_up_interruptible(&state->wait_queue);
	}
	spin_unlock_irqrestore(&state->lock, flags);
}

static int
do_adb_query(struct adb_request *req)
{
	int	ret = -EINVAL;

	switch(req->data[1])
	{
	case ADB_QUERY_GETDEVINFO:
		if (req->nbytes < 3)
			break;
		down(&adb_handler_sem);
		req->reply[0] = adb_handler[req->data[2]].original_address;
		req->reply[1] = adb_handler[req->data[2]].handler_id;
		up(&adb_handler_sem);
		req->complete = 1;
		req->reply_len = 2;
		adb_write_done(req);
		ret = 0;
		break;
	}
	return ret;
}

static int adb_open(struct inode *inode, struct file *file)
{
	struct adbdev_state *state;

	if (iminor(inode) > 0 || adb_controller == NULL)
		return -ENXIO;
	state = kmalloc(sizeof(struct adbdev_state), GFP_KERNEL);
	if (state == 0)
		return -ENOMEM;
	file->private_data = state;
	spin_lock_init(&state->lock);
	atomic_set(&state->n_pending, 0);
	state->completed = NULL;
	init_waitqueue_head(&state->wait_queue);
	state->inuse = 1;

	return 0;
}

static int adb_release(struct inode *inode, struct file *file)
{
	struct adbdev_state *state = file->private_data;
	unsigned long flags;

	lock_kernel();
	if (state) {
		file->private_data = NULL;
		spin_lock_irqsave(&state->lock, flags);
		if (atomic_read(&state->n_pending) == 0
		    && state->completed == NULL) {
			spin_unlock_irqrestore(&state->lock, flags);
			kfree(state);
		} else {
			state->inuse = 0;
			spin_unlock_irqrestore(&state->lock, flags);
		}
	}
	unlock_kernel();
	return 0;
}

static ssize_t adb_read(struct file *file, char __user *buf,
			size_t count, loff_t *ppos)
{
	int ret;
	struct adbdev_state *state = file->private_data;
	struct adb_request *req;
	wait_queue_t wait = __WAITQUEUE_INITIALIZER(wait,current);
	unsigned long flags;

	if (count < 2)
		return -EINVAL;
	if (count > sizeof(req->reply))
		count = sizeof(req->reply);
	ret = verify_area(VERIFY_WRITE, buf, count);
	if (ret)
		return ret;

	req = NULL;
	spin_lock_irqsave(&state->lock, flags);
	add_wait_queue(&state->wait_queue, &wait);
	current->state = TASK_INTERRUPTIBLE;

	for (;;) {
		req = state->completed;
		if (req != NULL)
			state->completed = req->next;
		else if (atomic_read(&state->n_pending) == 0)
			ret = -EIO;
		if (req != NULL || ret != 0)
			break;
		
		if (file->f_flags & O_NONBLOCK) {
			ret = -EAGAIN;
			break;
		}
		if (signal_pending(current)) {
			ret = -ERESTARTSYS;
			break;
		}
		spin_unlock_irqrestore(&state->lock, flags);
		schedule();
		spin_lock_irqsave(&state->lock, flags);
	}

	current->state = TASK_RUNNING;
	remove_wait_queue(&state->wait_queue, &wait);
	spin_unlock_irqrestore(&state->lock, flags);
	
	if (ret)
		return ret;

	ret = req->reply_len;
	if (ret > count)
		ret = count;
	if (ret > 0 && copy_to_user(buf, req->reply, ret))
		ret = -EFAULT;

	kfree(req);
	return ret;
}

static ssize_t adb_write(struct file *file, const char __user *buf,
			 size_t count, loff_t *ppos)
{
	int ret/*, i*/;
	struct adbdev_state *state = file->private_data;
	struct adb_request *req;

	if (count < 2 || count > sizeof(req->data))
		return -EINVAL;
	if (adb_controller == NULL)
		return -ENXIO;
	ret = verify_area(VERIFY_READ, buf, count);
	if (ret)
		return ret;

	req = (struct adb_request *) kmalloc(sizeof(struct adb_request),
					     GFP_KERNEL);
	if (req == NULL)
		return -ENOMEM;

	req->nbytes = count;
	req->done = adb_write_done;
	req->arg = (void *) state;
	req->complete = 0;
	
	ret = -EFAULT;
	if (copy_from_user(req->data, buf, count))
		goto out;

	atomic_inc(&state->n_pending);

	/* If a probe is in progress or we are sleeping, wait for it to complete */
	down(&adb_probe_mutex);

	/* Queries are special requests sent to the ADB driver itself */
	if (req->data[0] == ADB_QUERY) {
		if (count > 1)
			ret = do_adb_query(req);
		else
			ret = -EINVAL;
		up(&adb_probe_mutex);
	}
	/* Special case for ADB_BUSRESET request, all others are sent to
	   the controller */
	else if ((req->data[0] == ADB_PACKET)&&(count > 1)
		&&(req->data[1] == ADB_BUSRESET)) {
		ret = do_adb_reset_bus();
		up(&adb_probe_mutex);
		atomic_dec(&state->n_pending);
		if (ret == 0)
			ret = count;
		goto out;
	} else {	
		req->reply_expected = ((req->data[1] & 0xc) == 0xc);
		if (adb_controller && adb_controller->send_request)
			ret = adb_controller->send_request(req, 0);
		else
			ret = -ENXIO;
		up(&adb_probe_mutex);
	}

	if (ret != 0) {
		atomic_dec(&state->n_pending);
		goto out;
	}
	return count;

out:
	kfree(req);
	return ret;
}

static struct file_operations adb_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.read		= adb_read,
	.write		= adb_write,
	.open		= adb_open,
	.release	= adb_release,
};

static void
adbdev_init(void)
{
	if (register_chrdev(ADB_MAJOR, "adb", &adb_fops)) {
		printk(KERN_ERR "adb: unable to get major %d\n", ADB_MAJOR);
		return;
	}

	devfs_mk_cdev(MKDEV(ADB_MAJOR, 0), S_IFCHR | S_IRUSR | S_IWUSR, "adb");

	adb_dev_class = class_simple_create(THIS_MODULE, "adb");
	if (IS_ERR(adb_dev_class)) {
		return;
	}
	class_simple_device_add(adb_dev_class, MKDEV(ADB_MAJOR, 0), NULL, "adb");
}