vx_pcm.c

鼎力推荐！本程序是基于嵌入式LUNUX系统开发的源程序代码

	return vx_send_msg_nolock(chip, &rmh); /* no lock needed for trigger */ 
}


/*
 * vx_alloc_pipe - allocate a pipe and initialize the pipe instance
 * @capture: 0 = playback, 1 = capture operation
 * @audioid: the audio id to be assigned
 * @num_audio: number of audio channels
 * @pipep: the returned pipe instance
 *
 * return 0 on success, or a negative error code.
 */
static int vx_alloc_pipe(vx_core_t *chip, int capture,
			 int audioid, int num_audio,
			 vx_pipe_t **pipep)
{
	int err;
	vx_pipe_t *pipe;
	struct vx_rmh rmh;
	int data_mode;

	*pipep = NULL;
	vx_init_rmh(&rmh, CMD_RES_PIPE);
	vx_set_pipe_cmd_params(&rmh, capture, audioid, num_audio);
#if 0	// NYI
	if (underrun_skip_sound)
		rmh.Cmd[0] |= BIT_SKIP_SOUND;
#endif	// NYI
	data_mode = (chip->uer_bits & IEC958_AES0_NONAUDIO) != 0;
	if (! capture && data_mode)
		rmh.Cmd[0] |= BIT_DATA_MODE;
	err = vx_send_msg(chip, &rmh);
	if (err < 0)
		return err;

	/* initialize the pipe record */
	pipe = kcalloc(1, sizeof(*pipe), GFP_KERNEL);
	if (! pipe) {
		/* release the pipe */
		vx_init_rmh(&rmh, CMD_FREE_PIPE);
		vx_set_pipe_cmd_params(&rmh, capture, audioid, 0);
		vx_send_msg(chip, &rmh);
		return -ENOMEM;
	}

	/* the pipe index should be identical with the audio index */
	pipe->number = audioid;
	pipe->is_capture = capture;
	pipe->channels = num_audio;
	pipe->differed_type = 0;
	pipe->pcx_time = 0;
	pipe->data_mode = data_mode;
	*pipep = pipe;

	return 0;
}


/*
 * vx_free_pipe - release a pipe
 * @pipe: pipe to be released
 */
static int vx_free_pipe(vx_core_t *chip, vx_pipe_t *pipe)
{
	struct vx_rmh rmh;

	vx_init_rmh(&rmh, CMD_FREE_PIPE);
	vx_set_pipe_cmd_params(&rmh, pipe->is_capture, pipe->number, 0);
	vx_send_msg(chip, &rmh);

	kfree(pipe);
	return 0;
}


/*
 * vx_start_stream - start the stream
 *
 * called from trigger callback only
 */
static int vx_start_stream(vx_core_t *chip, vx_pipe_t *pipe)
{
	struct vx_rmh rmh;

	vx_init_rmh(&rmh, CMD_START_ONE_STREAM);
	vx_set_stream_cmd_params(&rmh, pipe->is_capture, pipe->number);
	vx_set_differed_time(chip, &rmh, pipe);
	return vx_send_msg_nolock(chip, &rmh); /* no lock needed for trigger */ 
}


/*
 * vx_stop_stream - stop the stream
 *
 * called from trigger callback only
 */
static int vx_stop_stream(vx_core_t *chip, vx_pipe_t *pipe)
{
	struct vx_rmh rmh;

	vx_init_rmh(&rmh, CMD_STOP_STREAM);
	vx_set_stream_cmd_params(&rmh, pipe->is_capture, pipe->number);
	return vx_send_msg_nolock(chip, &rmh); /* no lock needed for trigger */ 
}


/*
 * playback hw information
 */

static snd_pcm_hardware_t vx_pcm_playback_hw = {
	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
				 SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_MMAP_VALID |
				 SNDRV_PCM_INFO_RESUME),
	.formats =		/*SNDRV_PCM_FMTBIT_U8 |*/ SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_3LE,
	.rates =		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
	.rate_min =		5000,
	.rate_max =		48000,
	.channels_min =		1,
	.channels_max =		2,
	.buffer_bytes_max =	(128*1024),
	.period_bytes_min =	126,
	.period_bytes_max =	(128*1024),
	.periods_min =		2,
	.periods_max =		VX_MAX_PERIODS,
	.fifo_size =		126,
};


static void vx_pcm_delayed_start(unsigned long arg);

/*
 * vx_pcm_playback_open - open callback for playback
 */
static int vx_pcm_playback_open(snd_pcm_substream_t *subs)
{
	snd_pcm_runtime_t *runtime = subs->runtime;
	vx_core_t *chip = snd_pcm_substream_chip(subs);
	vx_pipe_t *pipe = NULL;
	unsigned int audio;
	int err;

	if (chip->chip_status & VX_STAT_IS_STALE)
		return -EBUSY;

	audio = subs->pcm->device * 2;
	snd_assert(audio < chip->audio_outs, return -EINVAL);
	
	/* playback pipe may have been already allocated for monitoring */
	pipe = chip->playback_pipes[audio];
	if (! pipe) {
		/* not allocated yet */
		err = vx_alloc_pipe(chip, 0, audio, 2, &pipe); /* stereo playback */
		if (err < 0)
			return err;
		chip->playback_pipes[audio] = pipe;
	}
	/* open for playback */
	pipe->references++;

	pipe->substream = subs;
	tasklet_init(&pipe->start_tq, vx_pcm_delayed_start, (unsigned long)subs);
	chip->playback_pipes[audio] = pipe;

	runtime->hw = vx_pcm_playback_hw;
	runtime->hw.period_bytes_min = chip->ibl.size;
	runtime->private_data = pipe;

	/* align to 4 bytes (otherwise will be problematic when 24bit is used) */ 
	snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 4);
	snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 4);

	return 0;
}

/*
 * vx_pcm_playback_close - close callback for playback
 */
static int vx_pcm_playback_close(snd_pcm_substream_t *subs)
{
	vx_core_t *chip = snd_pcm_substream_chip(subs);
	vx_pipe_t *pipe;

	if (! subs->runtime->private_data)
		return -EINVAL;

	pipe = subs->runtime->private_data;

	if (--pipe->references == 0) {
		chip->playback_pipes[pipe->number] = NULL;
		vx_free_pipe(chip, pipe);
	}

	return 0;

}


/*
 * vx_notify_end_of_buffer - send "end-of-buffer" notifier at the given pipe
 * @pipe: the pipe to notify
 *
 * NB: call with a certain lock.
 */
static int vx_notify_end_of_buffer(vx_core_t *chip, vx_pipe_t *pipe)
{
	int err;
	struct vx_rmh rmh;  /* use a temporary rmh here */

	/* Toggle Dsp Host Interface into Message mode */
	vx_send_rih_nolock(chip, IRQ_PAUSE_START_CONNECT);
	vx_init_rmh(&rmh, CMD_NOTIFY_END_OF_BUFFER);
	vx_set_stream_cmd_params(&rmh, 0, pipe->number);
	err = vx_send_msg_nolock(chip, &rmh);
	if (err < 0)
		return err;
	/* Toggle Dsp Host Interface back to sound transfer mode */
	vx_send_rih_nolock(chip, IRQ_PAUSE_START_CONNECT);
	return 0;
}

/*
 * vx_pcm_playback_transfer_chunk - transfer a single chunk
 * @subs: substream
 * @pipe: the pipe to transfer
 * @size: chunk size in bytes
 *
 * transfer a single buffer chunk.  EOB notificaton is added after that.
 * called from the interrupt handler, too.
 *
 * return 0 if ok.
 */
static int vx_pcm_playback_transfer_chunk(vx_core_t *chip, snd_pcm_runtime_t *runtime, vx_pipe_t *pipe, int size)
{
	int space, err = 0;

	space = vx_query_hbuffer_size(chip, pipe);
	if (space < 0) {
		/* disconnect the host, SIZE_HBUF command always switches to the stream mode */
		vx_send_rih(chip, IRQ_CONNECT_STREAM_NEXT);
		snd_printd("error hbuffer\n");
		return space;
	}
	if (space < size) {
		vx_send_rih(chip, IRQ_CONNECT_STREAM_NEXT);
		snd_printd("no enough hbuffer space %d\n", space);
		return -EIO; /* XRUN */
	}
		
	/* we don't need irqsave here, because this function
	 * is called from either trigger callback or irq handler
	 */
	spin_lock(&chip->lock); 
	vx_pseudo_dma_write(chip, runtime, pipe, size);
	err = vx_notify_end_of_buffer(chip, pipe);
	/* disconnect the host, SIZE_HBUF command always switches to the stream mode */
	vx_send_rih_nolock(chip, IRQ_CONNECT_STREAM_NEXT);
	spin_unlock(&chip->lock);
	return err;
}

/*
 * update the position of the given pipe.
 * pipe->position is updated and wrapped within the buffer size.
 * pipe->transferred is updated, too, but the size is not wrapped,
 * so that the caller can check the total transferred size later
 * (to call snd_pcm_period_elapsed).
 */
static int vx_update_pipe_position(vx_core_t *chip, snd_pcm_runtime_t *runtime, vx_pipe_t *pipe)
{
	struct vx_rmh rmh;
	int err, update;
	u64 count;

	vx_init_rmh(&rmh, CMD_STREAM_SAMPLE_COUNT);
	vx_set_pipe_cmd_params(&rmh, pipe->is_capture, pipe->number, 0);
	err = vx_send_msg(chip, &rmh);
	if (err < 0)
		return err;

	count = ((u64)(rmh.Stat[0] & 0xfffff) << 24) | (u64)rmh.Stat[1];
	update = (int)(count - pipe->cur_count);
	pipe->cur_count = count;
	pipe->position += update;
	if (pipe->position >= (int)runtime->buffer_size)
		pipe->position %= runtime->buffer_size;
	pipe->transferred += update;
	return 0;
}

/*
 * transfer the pending playback buffer data to DSP
 * called from interrupt handler
 */
static void vx_pcm_playback_transfer(vx_core_t *chip, snd_pcm_substream_t *subs, vx_pipe_t *pipe, int nchunks)
{
	int i, err;
	snd_pcm_runtime_t *runtime = subs->runtime;

	if (! pipe->prepared || (chip->chip_status & VX_STAT_IS_STALE))
		return;
	for (i = 0; i < nchunks; i++) {
		if ((err = vx_pcm_playback_transfer_chunk(chip, runtime, pipe,
							  chip->ibl.size)) < 0)
			return;
	}
}

/*
 * update the playback position and call snd_pcm_period_elapsed() if necessary
 * called from interrupt handler
 */
static void vx_pcm_playback_update(vx_core_t *chip, snd_pcm_substream_t *subs, vx_pipe_t *pipe)
{
	int err;
	snd_pcm_runtime_t *runtime = subs->runtime;

	if (pipe->running && ! (chip->chip_status & VX_STAT_IS_STALE)) {
		if ((err = vx_update_pipe_position(chip, runtime, pipe)) < 0)
			return;
		if (pipe->transferred >= (int)runtime->period_size) {
			pipe->transferred %= runtime->period_size;
			snd_pcm_period_elapsed(subs);
		}
	}
}

/*
 * start the stream and pipe.
 * this function is called from tasklet, which is invoked by the trigger
 * START callback.
 */
static void vx_pcm_delayed_start(unsigned long arg)
{
	snd_pcm_substream_t *subs = (snd_pcm_substream_t *)arg;
	vx_core_t *chip = subs->pcm->private_data;
	vx_pipe_t *pipe = subs->runtime->private_data;
	int err;

	/*  printk( KERN_DEBUG "DDDD tasklet delayed start jiffies = %ld\n", jiffies);*/

	if ((err = vx_start_stream(chip, pipe)) < 0) {
		snd_printk(KERN_ERR "vx: cannot start stream\n");
		return;
	}
	if ((err = vx_toggle_pipe(chip, pipe, 1)) < 0) {
		snd_printk(KERN_ERR "vx: cannot start pipe\n");
		return;
	}
	/*   printk( KERN_DEBUG "dddd tasklet delayed start jiffies = %ld \n", jiffies);*/
}

/*
 * vx_pcm_playback_trigger - trigger callback for playback
 */
static int vx_pcm_trigger(snd_pcm_substream_t *subs, int cmd)
{
	vx_core_t *chip = snd_pcm_substream_chip(subs);
	vx_pipe_t *pipe = subs->runtime->private_data;
	int err;

	if (chip->chip_status & VX_STAT_IS_STALE)
		return -EBUSY;
		
	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
		if (! pipe->is_capture)
			vx_pcm_playback_transfer(chip, subs, pipe, 2);
		/* FIXME:
		 * we trigger the pipe using tasklet, so that the interrupts are
		 * issued surely after the trigger is completed.
		 */ 
		tasklet_hi_schedule(&pipe->start_tq);
		chip->pcm_running++;
		pipe->running = 1;
		break;
	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
		vx_toggle_pipe(chip, pipe, 0);
		vx_stop_pipe(chip, pipe);
		vx_stop_stream(chip, pipe);
		chip->pcm_running--;
		pipe->running = 0;
		break;
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		if ((err = vx_toggle_pipe(chip, pipe, 0)) < 0)
			return err;
		break;
	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
		if ((err = vx_toggle_pipe(chip, pipe, 1)) < 0)
			return err;
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

/*
 * vx_pcm_playback_pointer - pointer callback for playback
 */
static snd_pcm_uframes_t vx_pcm_playback_pointer(snd_pcm_substream_t *subs)
{
	snd_pcm_runtime_t *runtime = subs->runtime;
	vx_pipe_t *pipe = runtime->private_data;
	return pipe->position;
}

/*
 * vx_pcm_hw_params - hw_params callback for playback and capture
 */
static int vx_pcm_hw_params(snd_pcm_substream_t *subs,
				     snd_pcm_hw_params_t *hw_params)
{
	return snd_pcm_alloc_vmalloc_buffer(subs, params_buffer_bytes(hw_params));
}

/*
 * vx_pcm_hw_free - hw_free callback for playback and capture
 */
static int vx_pcm_hw_free(snd_pcm_substream_t *subs)
{
	return snd_pcm_free_vmalloc_buffer(subs);
}

/*
 * vx_pcm_prepare - prepare callback for playback and capture
 */
static int vx_pcm_prepare(snd_pcm_substream_t *subs)
{
	vx_core_t *chip = snd_pcm_substream_chip(subs);
	snd_pcm_runtime_t *runtime = subs->runtime;
	vx_pipe_t *pipe = runtime->private_data;
	int err, data_mode;
	// int max_size, nchunks;