rawmidi.c

linux 内核源代码

	return -ENOIOCTLCMD;
}

/**
 * snd_rawmidi_receive - receive the input data from the device
 * @substream: the rawmidi substream
 * @buffer: the buffer pointer
 * @count: the data size to read
 *
 * Reads the data from the internal buffer.
 *
 * Returns the size of read data, or a negative error code on failure.
 */
int snd_rawmidi_receive(struct snd_rawmidi_substream *substream,
			const unsigned char *buffer, int count)
{
	unsigned long flags;
	int result = 0, count1;
	struct snd_rawmidi_runtime *runtime = substream->runtime;

	if (runtime->buffer == NULL) {
		snd_printd("snd_rawmidi_receive: input is not active!!!\n");
		return -EINVAL;
	}
	spin_lock_irqsave(&runtime->lock, flags);
	if (count == 1) {	/* special case, faster code */
		substream->bytes++;
		if (runtime->avail < runtime->buffer_size) {
			runtime->buffer[runtime->hw_ptr++] = buffer[0];
			runtime->hw_ptr %= runtime->buffer_size;
			runtime->avail++;
			result++;
		} else {
			runtime->xruns++;
		}
	} else {
		substream->bytes += count;
		count1 = runtime->buffer_size - runtime->hw_ptr;
		if (count1 > count)
			count1 = count;
		if (count1 > (int)(runtime->buffer_size - runtime->avail))
			count1 = runtime->buffer_size - runtime->avail;
		memcpy(runtime->buffer + runtime->hw_ptr, buffer, count1);
		runtime->hw_ptr += count1;
		runtime->hw_ptr %= runtime->buffer_size;
		runtime->avail += count1;
		count -= count1;
		result += count1;
		if (count > 0) {
			buffer += count1;
			count1 = count;
			if (count1 > (int)(runtime->buffer_size - runtime->avail)) {
				count1 = runtime->buffer_size - runtime->avail;
				runtime->xruns += count - count1;
			}
			if (count1 > 0) {
				memcpy(runtime->buffer, buffer, count1);
				runtime->hw_ptr = count1;
				runtime->avail += count1;
				result += count1;
			}
		}
	}
	if (result > 0) {
		if (runtime->event)
			tasklet_hi_schedule(&runtime->tasklet);
		else if (snd_rawmidi_ready(substream))
			wake_up(&runtime->sleep);
	}
	spin_unlock_irqrestore(&runtime->lock, flags);
	return result;
}

static long snd_rawmidi_kernel_read1(struct snd_rawmidi_substream *substream,
				     unsigned char *buf, long count, int kernel)
{
	unsigned long flags;
	long result = 0, count1;
	struct snd_rawmidi_runtime *runtime = substream->runtime;

	while (count > 0 && runtime->avail) {
		count1 = runtime->buffer_size - runtime->appl_ptr;
		if (count1 > count)
			count1 = count;
		spin_lock_irqsave(&runtime->lock, flags);
		if (count1 > (int)runtime->avail)
			count1 = runtime->avail;
		if (kernel) {
			memcpy(buf + result, runtime->buffer + runtime->appl_ptr, count1);
		} else {
			spin_unlock_irqrestore(&runtime->lock, flags);
			if (copy_to_user((char __user *)buf + result,
					 runtime->buffer + runtime->appl_ptr, count1)) {
				return result > 0 ? result : -EFAULT;
			}
			spin_lock_irqsave(&runtime->lock, flags);
		}
		runtime->appl_ptr += count1;
		runtime->appl_ptr %= runtime->buffer_size;
		runtime->avail -= count1;
		spin_unlock_irqrestore(&runtime->lock, flags);
		result += count1;
		count -= count1;
	}
	return result;
}

long snd_rawmidi_kernel_read(struct snd_rawmidi_substream *substream,
			     unsigned char *buf, long count)
{
	snd_rawmidi_input_trigger(substream, 1);
	return snd_rawmidi_kernel_read1(substream, buf, count, 1);
}

static ssize_t snd_rawmidi_read(struct file *file, char __user *buf, size_t count,
				loff_t *offset)
{
	long result;
	int count1;
	struct snd_rawmidi_file *rfile;
	struct snd_rawmidi_substream *substream;
	struct snd_rawmidi_runtime *runtime;

	rfile = file->private_data;
	substream = rfile->input;
	if (substream == NULL)
		return -EIO;
	runtime = substream->runtime;
	snd_rawmidi_input_trigger(substream, 1);
	result = 0;
	while (count > 0) {
		spin_lock_irq(&runtime->lock);
		while (!snd_rawmidi_ready(substream)) {
			wait_queue_t wait;
			if ((file->f_flags & O_NONBLOCK) != 0 || result > 0) {
				spin_unlock_irq(&runtime->lock);
				return result > 0 ? result : -EAGAIN;
			}
			init_waitqueue_entry(&wait, current);
			add_wait_queue(&runtime->sleep, &wait);
			set_current_state(TASK_INTERRUPTIBLE);
			spin_unlock_irq(&runtime->lock);
			schedule();
			remove_wait_queue(&runtime->sleep, &wait);
			if (signal_pending(current))
				return result > 0 ? result : -ERESTARTSYS;
			if (!runtime->avail)
				return result > 0 ? result : -EIO;
			spin_lock_irq(&runtime->lock);
		}
		spin_unlock_irq(&runtime->lock);
		count1 = snd_rawmidi_kernel_read1(substream,
						  (unsigned char __force *)buf,
						  count, 0);
		if (count1 < 0)
			return result > 0 ? result : count1;
		result += count1;
		buf += count1;
		count -= count1;
	}
	return result;
}

/**
 * snd_rawmidi_transmit_empty - check whether the output buffer is empty
 * @substream: the rawmidi substream
 * 
 * Returns 1 if the internal output buffer is empty, 0 if not.
 */
int snd_rawmidi_transmit_empty(struct snd_rawmidi_substream *substream)
{
	struct snd_rawmidi_runtime *runtime = substream->runtime;
	int result;
	unsigned long flags;

	if (runtime->buffer == NULL) {
		snd_printd("snd_rawmidi_transmit_empty: output is not active!!!\n");
		return 1;
	}
	spin_lock_irqsave(&runtime->lock, flags);
	result = runtime->avail >= runtime->buffer_size;
	spin_unlock_irqrestore(&runtime->lock, flags);
	return result;		
}

/**
 * snd_rawmidi_transmit_peek - copy data from the internal buffer
 * @substream: the rawmidi substream
 * @buffer: the buffer pointer
 * @count: data size to transfer
 *
 * Copies data from the internal output buffer to the given buffer.
 *
 * Call this in the interrupt handler when the midi output is ready,
 * and call snd_rawmidi_transmit_ack() after the transmission is
 * finished.
 *
 * Returns the size of copied data, or a negative error code on failure.
 */
int snd_rawmidi_transmit_peek(struct snd_rawmidi_substream *substream,
			      unsigned char *buffer, int count)
{
	unsigned long flags;
	int result, count1;
	struct snd_rawmidi_runtime *runtime = substream->runtime;

	if (runtime->buffer == NULL) {
		snd_printd("snd_rawmidi_transmit_peek: output is not active!!!\n");
		return -EINVAL;
	}
	result = 0;
	spin_lock_irqsave(&runtime->lock, flags);
	if (runtime->avail >= runtime->buffer_size) {
		/* warning: lowlevel layer MUST trigger down the hardware */
		goto __skip;
	}
	if (count == 1) {	/* special case, faster code */
		*buffer = runtime->buffer[runtime->hw_ptr];
		result++;
	} else {
		count1 = runtime->buffer_size - runtime->hw_ptr;
		if (count1 > count)
			count1 = count;
		if (count1 > (int)(runtime->buffer_size - runtime->avail))
			count1 = runtime->buffer_size - runtime->avail;
		memcpy(buffer, runtime->buffer + runtime->hw_ptr, count1);
		count -= count1;
		result += count1;
		if (count > 0) {
			if (count > (int)(runtime->buffer_size - runtime->avail - count1))
				count = runtime->buffer_size - runtime->avail - count1;
			memcpy(buffer + count1, runtime->buffer, count);
			result += count;
		}
	}
      __skip:
	spin_unlock_irqrestore(&runtime->lock, flags);
	return result;
}

/**
 * snd_rawmidi_transmit_ack - acknowledge the transmission
 * @substream: the rawmidi substream
 * @count: the tranferred count
 *
 * Advances the hardware pointer for the internal output buffer with
 * the given size and updates the condition.
 * Call after the transmission is finished.
 *
 * Returns the advanced size if successful, or a negative error code on failure.
 */
int snd_rawmidi_transmit_ack(struct snd_rawmidi_substream *substream, int count)
{
	unsigned long flags;
	struct snd_rawmidi_runtime *runtime = substream->runtime;

	if (runtime->buffer == NULL) {
		snd_printd("snd_rawmidi_transmit_ack: output is not active!!!\n");
		return -EINVAL;
	}
	spin_lock_irqsave(&runtime->lock, flags);
	snd_assert(runtime->avail + count <= runtime->buffer_size, );
	runtime->hw_ptr += count;
	runtime->hw_ptr %= runtime->buffer_size;
	runtime->avail += count;
	substream->bytes += count;
	if (count > 0) {
		if (runtime->drain || snd_rawmidi_ready(substream))
			wake_up(&runtime->sleep);
	}
	spin_unlock_irqrestore(&runtime->lock, flags);
	return count;
}

/**
 * snd_rawmidi_transmit - copy from the buffer to the device
 * @substream: the rawmidi substream
 * @buffer: the buffer pointer
 * @count: the data size to transfer
 * 
 * Copies data from the buffer to the device and advances the pointer.
 *
 * Returns the copied size if successful, or a negative error code on failure.
 */
int snd_rawmidi_transmit(struct snd_rawmidi_substream *substream,
			 unsigned char *buffer, int count)
{
	count = snd_rawmidi_transmit_peek(substream, buffer, count);
	if (count < 0)
		return count;
	return snd_rawmidi_transmit_ack(substream, count);
}

static long snd_rawmidi_kernel_write1(struct snd_rawmidi_substream *substream,
				      const unsigned char *buf, long count, int kernel)
{
	unsigned long flags;
	long count1, result;
	struct snd_rawmidi_runtime *runtime = substream->runtime;

	snd_assert(buf != NULL, return -EINVAL);
	snd_assert(runtime->buffer != NULL, return -EINVAL);

	result = 0;
	spin_lock_irqsave(&runtime->lock, flags);
	if (substream->append) {
		if ((long)runtime->avail < count) {
			spin_unlock_irqrestore(&runtime->lock, flags);
			return -EAGAIN;
		}
	}
	while (count > 0 && runtime->avail > 0) {
		count1 = runtime->buffer_size - runtime->appl_ptr;
		if (count1 > count)
			count1 = count;
		if (count1 > (long)runtime->avail)
			count1 = runtime->avail;
		if (kernel) {
			memcpy(runtime->buffer + runtime->appl_ptr, buf, count1);
		} else {
			spin_unlock_irqrestore(&runtime->lock, flags);
			if (copy_from_user(runtime->buffer + runtime->appl_ptr,
					   (char __user *)buf, count1)) {
				spin_lock_irqsave(&runtime->lock, flags);
				result = result > 0 ? result : -EFAULT;
				goto __end;
			}
			spin_lock_irqsave(&runtime->lock, flags);
		}
		runtime->appl_ptr += count1;
		runtime->appl_ptr %= runtime->buffer_size;
		runtime->avail -= count1;
		result += count1;
		buf += count1;
		count -= count1;
	}
      __end:
	count1 = runtime->avail < runtime->buffer_size;
	spin_unlock_irqrestore(&runtime->lock, flags);
	if (count1)
		snd_rawmidi_output_trigger(substream, 1);
	return result;
}

long snd_rawmidi_kernel_write(struct snd_rawmidi_substream *substream,
			      const unsigned char *buf, long count)
{
	return snd_rawmidi_kernel_write1(substream, buf, count, 1);
}

static ssize_t snd_rawmidi_write(struct file *file, const char __user *buf,
				 size_t count, loff_t *offset)
{
	long result, timeout;
	int count1;
	struct snd_rawmidi_file *rfile;
	struct snd_rawmidi_runtime *runtime;
	struct snd_rawmidi_substream *substream;

	rfile = file->private_data;
	substream = rfile->output;
	runtime = substream->runtime;
	/* we cannot put an atomic message to our buffer */
	if (substream->append && count > runtime->buffer_size)
		return -EIO;
	result = 0;
	while (count > 0) {
		spin_lock_irq(&runtime->lock);
		while (!snd_rawmidi_ready_append(substream, count)) {
			wait_queue_t wait;
			if (file->f_flags & O_NONBLOCK) {
				spin_unlock_irq(&runtime->lock);
				return result > 0 ? result : -EAGAIN;
			}
			init_waitqueue_entry(&wait, current);
			add_wait_queue(&runtime->sleep, &wait);
			set_current_state(TASK_INTERRUPTIBLE);
			spin_unlock_irq(&runtime->lock);
			timeout = schedule_timeout(30 * HZ);
			remove_wait_queue(&runtime->sleep, &wait);
			if (signal_pending(current))
				return result > 0 ? result : -ERESTARTSYS;
			if (!runtime->avail && !timeout)
				return result > 0 ? result : -EIO;
			spin_lock_irq(&runtime->lock);
		}
		spin_unlock_irq(&runtime->lock);
		count1 = snd_rawmidi_kernel_write1(substream,
						   (unsigned char __force *)buf,
						   count, 0);
		if (count1 < 0)
			return result > 0 ? result : count1;
		result += count1;
		buf += count1;
		if ((size_t)count1 < count && (file->f_flags & O_NONBLOCK))
			break;
		count -= count1;
	}
	if (file->f_flags & O_SYNC) {
		spin_lock_irq(&runtime->lock);
		while (runtime->avail != runtime->buffer_size) {
			wait_queue_t wait;
			unsigned int last_avail = runtime->avail;
			init_waitqueue_entry(&wait, current);
			add_wait_queue(&runtime->sleep, &wait);
			set_current_state(TASK_INTERRUPTIBLE);
			spin_unlock_irq(&runtime->lock);
			timeout = schedule_timeout(30 * HZ);
			remove_wait_queue(&runtime->sleep, &wait);
			if (signal_pending(current))
				return result > 0 ? result : -ERESTARTSYS;
			if (runtime->avail == last_avail && !timeout)
				return result > 0 ? result : -EIO;
			spin_lock_irq(&runtime->lock);
		}
		spin_unlock_irq(&runtime->lock);
	}
	return result;
}