pcm_oss.c

是关于linux2.5.1的完全源码

	runtime->oss.format = snd_pcm_oss_format_to(params_format(&params));
	runtime->oss.channels = params_channels(&params);
	runtime->oss.rate = params_rate(&params);

	runtime->oss.params = 0;
	runtime->oss.prepare = 1;
	if (runtime->oss.buffer != NULL)
		vfree(runtime->oss.buffer);
	runtime->oss.buffer = vmalloc(runtime->oss.period_bytes);
	runtime->oss.buffer_used = 0;
	snd_assert(runtime->dma_area != NULL, return -EIO);
	snd_pcm_format_set_silence(runtime->format, runtime->dma_area, bytes_to_samples(runtime, runtime->dma_bytes));
	return 0;
}

static int snd_pcm_oss_get_active_substream(snd_pcm_oss_file_t *pcm_oss_file, snd_pcm_substream_t **r_substream)
{
	int idx, err;
	snd_pcm_substream_t *asubstream = NULL, *substream;

	for (idx = 0; idx < 2; idx++) {
		substream = pcm_oss_file->streams[idx];
		if (substream == NULL)
			continue;
		if (asubstream == NULL)
			asubstream = substream;
		if (substream->runtime->oss.params) {
			err = snd_pcm_oss_change_params(substream);
			if (err < 0)
				return err;
		}
	}
	snd_assert(asubstream != NULL, return -EIO);
	if (r_substream)
		*r_substream = asubstream;
	return 0;
}

static int snd_pcm_oss_prepare(snd_pcm_substream_t *substream)
{
	int err;
	snd_pcm_runtime_t *runtime = substream->runtime;

	err = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_PREPARE, 0);
	if (err < 0) {
		snd_printd("snd_pcm_oss_prepare: SNDRV_PCM_IOCTL_PREPARE failed\n");
		return err;
	}
	runtime->oss.prepare = 0;
	runtime->oss.prev_hw_ptr_interrupt = 0;

	return 0;
}

static int snd_pcm_oss_make_ready(snd_pcm_substream_t *substream)
{
	snd_pcm_runtime_t *runtime;
	int err;

	if (substream == NULL)
		return 0;
	runtime = substream->runtime;
	if (runtime->oss.params) {
		err = snd_pcm_oss_change_params(substream);
		if (err < 0)
			return err;
	}
	if (runtime->oss.prepare) {
		err = snd_pcm_oss_prepare(substream);
		if (err < 0)
			return err;
	}
	return 0;
}

snd_pcm_sframes_t snd_pcm_oss_write3(snd_pcm_substream_t *substream, const char *ptr, snd_pcm_uframes_t frames, int in_kernel)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	int ret;
	while (1) {
		if (runtime->status->state == SNDRV_PCM_STATE_XRUN ||
		    runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
			ret = snd_pcm_oss_prepare(substream);
			if (ret < 0)
				break;
		}
		if (in_kernel) {
			mm_segment_t fs;
			fs = snd_enter_user();
			ret = snd_pcm_lib_write(substream, ptr, frames);
			snd_leave_user(fs);
		} else {
			ret = snd_pcm_lib_write(substream, ptr, frames);
		}
		if (ret != -EPIPE && ret != -ESTRPIPE)
			break;
		/* test, if we can't store new data, because the stream */
		/* has not been started */
		if (runtime->status->state == SNDRV_PCM_STATE_PREPARED)
			return -EAGAIN;
	}
	return ret;
}

snd_pcm_sframes_t snd_pcm_oss_read3(snd_pcm_substream_t *substream, char *ptr, snd_pcm_uframes_t frames, int in_kernel)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	int ret;
	while (1) {
		if (runtime->status->state == SNDRV_PCM_STATE_XRUN ||
		    runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
			ret = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DRAIN, 0);
			if (ret < 0)
				break;
		} else if (runtime->status->state == SNDRV_PCM_STATE_SETUP) {
			ret = snd_pcm_oss_prepare(substream);
			if (ret < 0)
				break;
		}
		ret = snd_pcm_lib_read(substream, ptr, frames);
		if (in_kernel) {
			mm_segment_t fs;
			fs = snd_enter_user();
			ret = snd_pcm_lib_read(substream, ptr, frames);
			snd_leave_user(fs);
		} else {
			ret = snd_pcm_lib_read(substream, ptr, frames);
		}
		if (ret != -EPIPE && ret != -ESTRPIPE)
			break;
	}
	return ret;
}

snd_pcm_sframes_t snd_pcm_oss_writev3(snd_pcm_substream_t *substream, void **bufs, snd_pcm_uframes_t frames, int in_kernel)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	int ret;
	while (1) {
		if (runtime->status->state == SNDRV_PCM_STATE_XRUN ||
		    runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
			ret = snd_pcm_oss_prepare(substream);
			if (ret < 0)
				break;
		}
		if (in_kernel) {
			mm_segment_t fs;
			fs = snd_enter_user();
			ret = snd_pcm_lib_writev(substream, bufs, frames);
			snd_leave_user(fs);
		} else {
			ret = snd_pcm_lib_writev(substream, bufs, frames);
		}
		if (ret != -EPIPE && ret != -ESTRPIPE)
			break;

		/* test, if we can't store new data, because the stream */
		/* has not been started */
		if (runtime->status->state == SNDRV_PCM_STATE_PREPARED)
			return -EAGAIN;
	}
	return ret;
}
	
snd_pcm_sframes_t snd_pcm_oss_readv3(snd_pcm_substream_t *substream, void **bufs, snd_pcm_uframes_t frames, int in_kernel)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	int ret;
	while (1) {
		if (runtime->status->state == SNDRV_PCM_STATE_XRUN ||
		    runtime->status->state == SNDRV_PCM_STATE_SUSPENDED) {
			ret = snd_pcm_kernel_ioctl(substream, SNDRV_PCM_IOCTL_DRAIN, 0);
			if (ret < 0)
				break;
		} else if (runtime->status->state == SNDRV_PCM_STATE_SETUP) {
			ret = snd_pcm_oss_prepare(substream);
			if (ret < 0)
				break;
		}
		if (in_kernel) {
			mm_segment_t fs;
			fs = snd_enter_user();
			ret = snd_pcm_lib_readv(substream, bufs, frames);
			snd_leave_user(fs);
		} else {
			ret = snd_pcm_lib_readv(substream, bufs, frames);
		}
		if (ret != -EPIPE && ret != -ESTRPIPE)
			break;
	}
	return ret;
}

static ssize_t snd_pcm_oss_write2(snd_pcm_substream_t *substream, const char *buf, size_t bytes, int in_kernel)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	snd_pcm_sframes_t frames, frames1;
	if (runtime->oss.plugin_first) {
		snd_pcm_plugin_channel_t *channels;
		size_t oss_frame_bytes = (runtime->oss.plugin_first->src_width * runtime->oss.plugin_first->src_format.channels) / 8;
		if (!in_kernel) {
			if (copy_from_user(runtime->oss.buffer, buf, bytes))
				return -EFAULT;
			buf = runtime->oss.buffer;
		}
		frames = bytes / oss_frame_bytes;
		frames1 = snd_pcm_plug_client_channels_buf(substream, (char *)buf, frames, &channels);
		if (frames1 < 0)
			return frames1;
		frames1 = snd_pcm_plug_write_transfer(substream, channels, frames1);
		if (frames1 <= 0)
			return frames1;
		bytes = frames1 * oss_frame_bytes;
	} else {
		frames = bytes_to_frames(runtime, bytes);
		frames1 = snd_pcm_oss_write3(substream, buf, frames, in_kernel);
		if (frames1 <= 0)
			return frames1;
		bytes = frames_to_bytes(runtime, frames1);
	}
	return bytes;
}

static ssize_t snd_pcm_oss_write1(snd_pcm_substream_t *substream, const char *buf, size_t bytes)
{
	size_t xfer = 0;
	ssize_t tmp;
	snd_pcm_runtime_t *runtime = substream->runtime;

	if (atomic_read(&runtime->mmap_count))
		return -ENXIO;

	if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
		return tmp;
	while (bytes > 0) {
		if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
			tmp = bytes;
			if (tmp + runtime->oss.buffer_used > runtime->oss.period_bytes)
				tmp = runtime->oss.period_bytes - runtime->oss.buffer_used;
			if (tmp > 0) {
				if (copy_from_user(runtime->oss.buffer + runtime->oss.buffer_used, buf, tmp))
					return xfer > 0 ? xfer : -EFAULT;
			}
			runtime->oss.buffer_used += tmp;
			buf += tmp;
			bytes -= tmp;
			xfer += tmp;
			if (runtime->oss.buffer_used == runtime->oss.period_bytes) {
				tmp = snd_pcm_oss_write2(substream, runtime->oss.buffer, runtime->oss.period_bytes, 1);
				if (tmp <= 0)
					return xfer > 0 ? xfer : tmp;
				runtime->oss.bytes += tmp;
				runtime->oss.buffer_used = 0;
			}
		} else {
			tmp = snd_pcm_oss_write2(substream, (char *)buf, runtime->oss.period_bytes, 0);
			if (tmp <= 0)
				return xfer > 0 ? xfer : tmp;
			runtime->oss.bytes += tmp;
			buf += tmp;
			bytes -= tmp;
			xfer += tmp;
		}
	}
	return xfer;
}

static ssize_t snd_pcm_oss_read2(snd_pcm_substream_t *substream, char *buf, size_t bytes, int in_kernel)
{
	snd_pcm_runtime_t *runtime = substream->runtime;
	snd_pcm_sframes_t frames, frames1;
	char *final_dst = buf;
	if (runtime->oss.plugin_first) {
		snd_pcm_plugin_channel_t *channels;
		size_t oss_frame_bytes = (runtime->oss.plugin_last->dst_width * runtime->oss.plugin_last->dst_format.channels) / 8;
		if (!in_kernel)
			buf = runtime->oss.buffer;
		frames = bytes / oss_frame_bytes;
		frames1 = snd_pcm_plug_client_channels_buf(substream, buf, frames, &channels);
		if (frames1 < 0)
			return frames1;
		frames1 = snd_pcm_plug_read_transfer(substream, channels, frames1);
		if (frames1 <= 0)
			return frames1;
		bytes = frames1 * oss_frame_bytes;
		if (!in_kernel && copy_to_user(final_dst, buf, bytes))
			return -EFAULT;
	} else {
		frames = bytes_to_frames(runtime, bytes);
		frames1 = snd_pcm_oss_read3(substream, buf, frames, in_kernel);
		if (frames1 <= 0)
			return frames1;
		bytes = frames_to_bytes(runtime, frames1);
	}
	return bytes;
}

static ssize_t snd_pcm_oss_read1(snd_pcm_substream_t *substream, char *buf, size_t bytes)
{
	size_t xfer = 0;
	ssize_t tmp;
	snd_pcm_runtime_t *runtime = substream->runtime;

	if (atomic_read(&runtime->mmap_count))
		return -ENXIO;

	if ((tmp = snd_pcm_oss_make_ready(substream)) < 0)
		return tmp;
	while (bytes > 0) {
		if (bytes < runtime->oss.period_bytes || runtime->oss.buffer_used > 0) {
			if (runtime->oss.buffer_used == 0) {
				tmp = snd_pcm_oss_read2(substream, runtime->oss.buffer, runtime->oss.period_bytes, 1);
				if (tmp <= 0)
					return xfer > 0 ? xfer : tmp;
				runtime->oss.bytes += tmp;
				runtime->oss.buffer_used = runtime->oss.period_bytes;
			}
			tmp = bytes;
			if ((size_t) tmp > runtime->oss.buffer_used)
				tmp = runtime->oss.buffer_used;
			if (copy_to_user(buf, runtime->oss.buffer + (runtime->oss.period_bytes - runtime->oss.buffer_used), tmp))
				return xfer > 0 ? xfer : -EFAULT;
			buf += tmp;
			bytes -= tmp;
			xfer += tmp;
			runtime->oss.buffer_used -= tmp;
		} else {
			tmp = snd_pcm_oss_read2(substream, (char *)buf, runtime->oss.period_bytes, 0);
			if (tmp <= 0)
				return xfer > 0 ? xfer : tmp;
			runtime->oss.bytes += tmp;
			buf += tmp;
			bytes -= tmp;
			xfer += tmp;
		}
	}
	return xfer;
}

static int snd_pcm_oss_reset(snd_pcm_oss_file_t *pcm_oss_file)
{
	snd_pcm_substream_t *substream;

	substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_PLAYBACK];
	if (substream != NULL) {
		snd_pcm_kernel_playback_ioctl(substream, SNDRV_PCM_IOCTL_DROP, 0);
		substream->runtime->oss.prepare = 1;
	}
	substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_CAPTURE];
	if (substream != NULL) {
		snd_pcm_kernel_capture_ioctl(substream, SNDRV_PCM_IOCTL_DROP, 0);
		substream->runtime->oss.prepare = 1;
	}
	return 0;
}

static int snd_pcm_oss_sync(snd_pcm_oss_file_t *pcm_oss_file)
{
	int err = 0;
	unsigned int saved_f_flags;
	snd_pcm_substream_t *substream;
	snd_pcm_runtime_t *runtime;
	ssize_t result;
	wait_queue_t wait;

	substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_PLAYBACK];
	if (substream != NULL) {
		if ((err = snd_pcm_oss_make_ready(substream)) < 0)
			return err;
		
		runtime = substream->runtime;
		if (runtime->oss.buffer_used > 0) {
			snd_pcm_format_set_silence(runtime->format,
						   runtime->oss.buffer + runtime->oss.buffer_used,
						   bytes_to_samples(runtime, runtime->oss.period_bytes - runtime->oss.buffer_used));
			init_waitqueue_entry(&wait, current);
			add_wait_queue(&runtime->sleep, &wait);
			while (1) {
				result = snd_pcm_oss_write2(substream, runtime->oss.buffer, runtime->oss.period_bytes, 1);
				if (result > 0) {
					runtime->oss.buffer_used = 0;
					break;
				}
				if (result != 0 && result != -EAGAIN)
					break;
				set_current_state(TASK_INTERRUPTIBLE);
				schedule();
				if (signal_pending(current)) {
					result = -ERESTARTSYS;
					break;
				}
			}
			set_current_state(TASK_RUNNING);
			remove_wait_queue(&runtime->sleep, &wait);
			if (result < 0)
				return result;
		}
		saved_f_flags = substream->ffile->f_flags;
		substream->ffile->f_flags &= ~O_NONBLOCK;
		err = snd_pcm_kernel_playback_ioctl(substream, SNDRV_PCM_IOCTL_DRAIN, 0);
		substream->ffile->f_flags = saved_f_flags;
		if (err < 0)
			return err;
		runtime->oss.prepare = 1;
	}

	substream = pcm_oss_file->streams[SNDRV_PCM_STREAM_CAPTURE];
	if (substream != NULL) {
		if ((err = snd_pcm_oss_make_ready(substream)) < 0)
			return err;
		runtime = substream->runtime;
		err = snd_pcm_kernel_capture_ioctl(substream, SNDRV_PCM_IOCTL_DROP, 0);
		if (err < 0)
			return err;
		runtime->oss.buffer_used = 0;
		runtime->oss.prepare = 1;
	}
	return 0;
}

static int snd_pcm_oss_set_rate(snd_pcm_oss_file_t *pcm_oss_file, int rate)
{
	int idx;

	for (idx = 1; idx >= 0; --idx) {
		snd_pcm_substream_t *substream = pcm_oss_file->streams[idx];
		snd_pcm_runtime_t *runtime;
		if (substream == NULL)
			continue;
		runtime = substream->runtime;
		if (rate < 1000)
			rate = 1000;
		else if (rate > 48000)
			rate = 48000;
		if (runtime->oss.rate != rate) {
			runtime->oss.params = 1;
			runtime->oss.rate = rate;
		}
	}
	return snd_pcm_oss_get_rate(pcm_oss_file);