pcm_lib.c

linux 内核源代码

 * @r: struct snd_ratdens constriants
 */
int snd_pcm_hw_constraint_ratdens(struct snd_pcm_runtime *runtime, 
				  unsigned int cond,
				  snd_pcm_hw_param_t var,
				  struct snd_pcm_hw_constraint_ratdens *r)
{
	return snd_pcm_hw_rule_add(runtime, cond, var,
				   snd_pcm_hw_rule_ratdens, r,
				   var, -1);
}

EXPORT_SYMBOL(snd_pcm_hw_constraint_ratdens);

static int snd_pcm_hw_rule_msbits(struct snd_pcm_hw_params *params,
				  struct snd_pcm_hw_rule *rule)
{
	unsigned int l = (unsigned long) rule->private;
	int width = l & 0xffff;
	unsigned int msbits = l >> 16;
	struct snd_interval *i = hw_param_interval(params, SNDRV_PCM_HW_PARAM_SAMPLE_BITS);
	if (snd_interval_single(i) && snd_interval_value(i) == width)
		params->msbits = msbits;
	return 0;
}

/**
 * snd_pcm_hw_constraint_msbits
 * @runtime: PCM runtime instance
 * @cond: condition bits
 * @width: sample bits width
 * @msbits: msbits width
 */
int snd_pcm_hw_constraint_msbits(struct snd_pcm_runtime *runtime, 
				 unsigned int cond,
				 unsigned int width,
				 unsigned int msbits)
{
	unsigned long l = (msbits << 16) | width;
	return snd_pcm_hw_rule_add(runtime, cond, -1,
				    snd_pcm_hw_rule_msbits,
				    (void*) l,
				    SNDRV_PCM_HW_PARAM_SAMPLE_BITS, -1);
}

EXPORT_SYMBOL(snd_pcm_hw_constraint_msbits);

static int snd_pcm_hw_rule_step(struct snd_pcm_hw_params *params,
				struct snd_pcm_hw_rule *rule)
{
	unsigned long step = (unsigned long) rule->private;
	return snd_interval_step(hw_param_interval(params, rule->var), 0, step);
}

/**
 * snd_pcm_hw_constraint_step
 * @runtime: PCM runtime instance
 * @cond: condition bits
 * @var: hw_params variable to apply the step constraint
 * @step: step size
 */
int snd_pcm_hw_constraint_step(struct snd_pcm_runtime *runtime,
			       unsigned int cond,
			       snd_pcm_hw_param_t var,
			       unsigned long step)
{
	return snd_pcm_hw_rule_add(runtime, cond, var, 
				   snd_pcm_hw_rule_step, (void *) step,
				   var, -1);
}

EXPORT_SYMBOL(snd_pcm_hw_constraint_step);

static int snd_pcm_hw_rule_pow2(struct snd_pcm_hw_params *params, struct snd_pcm_hw_rule *rule)
{
	static int pow2_sizes[] = {
		1<<0, 1<<1, 1<<2, 1<<3, 1<<4, 1<<5, 1<<6, 1<<7,
		1<<8, 1<<9, 1<<10, 1<<11, 1<<12, 1<<13, 1<<14, 1<<15,
		1<<16, 1<<17, 1<<18, 1<<19, 1<<20, 1<<21, 1<<22, 1<<23,
		1<<24, 1<<25, 1<<26, 1<<27, 1<<28, 1<<29, 1<<30
	};
	return snd_interval_list(hw_param_interval(params, rule->var),
				 ARRAY_SIZE(pow2_sizes), pow2_sizes, 0);
}		

/**
 * snd_pcm_hw_constraint_pow2
 * @runtime: PCM runtime instance
 * @cond: condition bits
 * @var: hw_params variable to apply the power-of-2 constraint
 */
int snd_pcm_hw_constraint_pow2(struct snd_pcm_runtime *runtime,
			       unsigned int cond,
			       snd_pcm_hw_param_t var)
{
	return snd_pcm_hw_rule_add(runtime, cond, var, 
				   snd_pcm_hw_rule_pow2, NULL,
				   var, -1);
}

EXPORT_SYMBOL(snd_pcm_hw_constraint_pow2);

static void _snd_pcm_hw_param_any(struct snd_pcm_hw_params *params,
				  snd_pcm_hw_param_t var)
{
	if (hw_is_mask(var)) {
		snd_mask_any(hw_param_mask(params, var));
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
		return;
	}
	if (hw_is_interval(var)) {
		snd_interval_any(hw_param_interval(params, var));
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
		return;
	}
	snd_BUG();
}

void _snd_pcm_hw_params_any(struct snd_pcm_hw_params *params)
{
	unsigned int k;
	memset(params, 0, sizeof(*params));
	for (k = SNDRV_PCM_HW_PARAM_FIRST_MASK; k <= SNDRV_PCM_HW_PARAM_LAST_MASK; k++)
		_snd_pcm_hw_param_any(params, k);
	for (k = SNDRV_PCM_HW_PARAM_FIRST_INTERVAL; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++)
		_snd_pcm_hw_param_any(params, k);
	params->info = ~0U;
}

EXPORT_SYMBOL(_snd_pcm_hw_params_any);

/**
 * snd_pcm_hw_param_value
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Return the value for field PAR if it's fixed in configuration space 
 *  defined by PARAMS. Return -EINVAL otherwise
 */
int snd_pcm_hw_param_value(const struct snd_pcm_hw_params *params,
			   snd_pcm_hw_param_t var, int *dir)
{
	if (hw_is_mask(var)) {
		const struct snd_mask *mask = hw_param_mask_c(params, var);
		if (!snd_mask_single(mask))
			return -EINVAL;
		if (dir)
			*dir = 0;
		return snd_mask_value(mask);
	}
	if (hw_is_interval(var)) {
		const struct snd_interval *i = hw_param_interval_c(params, var);
		if (!snd_interval_single(i))
			return -EINVAL;
		if (dir)
			*dir = i->openmin;
		return snd_interval_value(i);
	}
	return -EINVAL;
}

EXPORT_SYMBOL(snd_pcm_hw_param_value);

void _snd_pcm_hw_param_setempty(struct snd_pcm_hw_params *params,
				snd_pcm_hw_param_t var)
{
	if (hw_is_mask(var)) {
		snd_mask_none(hw_param_mask(params, var));
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	} else if (hw_is_interval(var)) {
		snd_interval_none(hw_param_interval(params, var));
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	} else {
		snd_BUG();
	}
}

EXPORT_SYMBOL(_snd_pcm_hw_param_setempty);

static int _snd_pcm_hw_param_first(struct snd_pcm_hw_params *params,
				   snd_pcm_hw_param_t var)
{
	int changed;
	if (hw_is_mask(var))
		changed = snd_mask_refine_first(hw_param_mask(params, var));
	else if (hw_is_interval(var))
		changed = snd_interval_refine_first(hw_param_interval(params, var));
	else
		return -EINVAL;
	if (changed) {
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	}
	return changed;
}


/**
 * snd_pcm_hw_param_first
 * @pcm: PCM instance
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Inside configuration space defined by PARAMS remove from PAR all 
 * values > minimum. Reduce configuration space accordingly.
 * Return the minimum.
 */
int snd_pcm_hw_param_first(struct snd_pcm_substream *pcm, 
			   struct snd_pcm_hw_params *params, 
			   snd_pcm_hw_param_t var, int *dir)
{
	int changed = _snd_pcm_hw_param_first(params, var);
	if (changed < 0)
		return changed;
	if (params->rmask) {
		int err = snd_pcm_hw_refine(pcm, params);
		snd_assert(err >= 0, return err);
	}
	return snd_pcm_hw_param_value(params, var, dir);
}

EXPORT_SYMBOL(snd_pcm_hw_param_first);

static int _snd_pcm_hw_param_last(struct snd_pcm_hw_params *params,
				  snd_pcm_hw_param_t var)
{
	int changed;
	if (hw_is_mask(var))
		changed = snd_mask_refine_last(hw_param_mask(params, var));
	else if (hw_is_interval(var))
		changed = snd_interval_refine_last(hw_param_interval(params, var));
	else
		return -EINVAL;
	if (changed) {
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	}
	return changed;
}


/**
 * snd_pcm_hw_param_last
 * @pcm: PCM instance
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Inside configuration space defined by PARAMS remove from PAR all 
 * values < maximum. Reduce configuration space accordingly.
 * Return the maximum.
 */
int snd_pcm_hw_param_last(struct snd_pcm_substream *pcm, 
			  struct snd_pcm_hw_params *params,
			  snd_pcm_hw_param_t var, int *dir)
{
	int changed = _snd_pcm_hw_param_last(params, var);
	if (changed < 0)
		return changed;
	if (params->rmask) {
		int err = snd_pcm_hw_refine(pcm, params);
		snd_assert(err >= 0, return err);
	}
	return snd_pcm_hw_param_value(params, var, dir);
}

EXPORT_SYMBOL(snd_pcm_hw_param_last);

/**
 * snd_pcm_hw_param_choose
 * @pcm: PCM instance
 * @params: the hw_params instance
 *
 * Choose one configuration from configuration space defined by PARAMS
 * The configuration chosen is that obtained fixing in this order:
 * first access, first format, first subformat, min channels,
 * min rate, min period time, max buffer size, min tick time
 */
int snd_pcm_hw_params_choose(struct snd_pcm_substream *pcm,
			     struct snd_pcm_hw_params *params)
{
	static int vars[] = {
		SNDRV_PCM_HW_PARAM_ACCESS,
		SNDRV_PCM_HW_PARAM_FORMAT,
		SNDRV_PCM_HW_PARAM_SUBFORMAT,
		SNDRV_PCM_HW_PARAM_CHANNELS,
		SNDRV_PCM_HW_PARAM_RATE,
		SNDRV_PCM_HW_PARAM_PERIOD_TIME,
		SNDRV_PCM_HW_PARAM_BUFFER_SIZE,
		SNDRV_PCM_HW_PARAM_TICK_TIME,
		-1
	};
	int err, *v;

	for (v = vars; *v != -1; v++) {
		if (*v != SNDRV_PCM_HW_PARAM_BUFFER_SIZE)
			err = snd_pcm_hw_param_first(pcm, params, *v, NULL);
		else
			err = snd_pcm_hw_param_last(pcm, params, *v, NULL);
		snd_assert(err >= 0, return err);
	}
	return 0;
}

static int snd_pcm_lib_ioctl_reset(struct snd_pcm_substream *substream,
				   void *arg)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	unsigned long flags;
	snd_pcm_stream_lock_irqsave(substream, flags);
	if (snd_pcm_running(substream) &&
	    snd_pcm_update_hw_ptr(substream) >= 0)
		runtime->status->hw_ptr %= runtime->buffer_size;
	else
		runtime->status->hw_ptr = 0;
	snd_pcm_stream_unlock_irqrestore(substream, flags);
	return 0;
}

static int snd_pcm_lib_ioctl_channel_info(struct snd_pcm_substream *substream,
					  void *arg)
{
	struct snd_pcm_channel_info *info = arg;
	struct snd_pcm_runtime *runtime = substream->runtime;
	int width;
	if (!(runtime->info & SNDRV_PCM_INFO_MMAP)) {
		info->offset = -1;
		return 0;
	}
	width = snd_pcm_format_physical_width(runtime->format);
	if (width < 0)
		return width;
	info->offset = 0;
	switch (runtime->access) {
	case SNDRV_PCM_ACCESS_MMAP_INTERLEAVED:
	case SNDRV_PCM_ACCESS_RW_INTERLEAVED:
		info->first = info->channel * width;
		info->step = runtime->channels * width;
		break;
	case SNDRV_PCM_ACCESS_MMAP_NONINTERLEAVED:
	case SNDRV_PCM_ACCESS_RW_NONINTERLEAVED:
	{
		size_t size = runtime->dma_bytes / runtime->channels;
		info->first = info->channel * size * 8;
		info->step = width;
		break;
	}
	default:
		snd_BUG();
		break;
	}
	return 0;
}

/**
 * snd_pcm_lib_ioctl - a generic PCM ioctl callback
 * @substream: the pcm substream instance
 * @cmd: ioctl command
 * @arg: ioctl argument
 *
 * Processes the generic ioctl commands for PCM.
 * Can be passed as the ioctl callback for PCM ops.
 *
 * Returns zero if successful, or a negative error code on failure.
 */
int snd_pcm_lib_ioctl(struct snd_pcm_substream *substream,
		      unsigned int cmd, void *arg)
{
	switch (cmd) {
	case SNDRV_PCM_IOCTL1_INFO:
		return 0;
	case SNDRV_PCM_IOCTL1_RESET:
		return snd_pcm_lib_ioctl_reset(substream, arg);
	case SNDRV_PCM_IOCTL1_CHANNEL_INFO:
		return snd_pcm_lib_ioctl_channel_info(substream, arg);
	}
	return -ENXIO;
}

EXPORT_SYMBOL(snd_pcm_lib_ioctl);

/*
 *  Conditions
 */

static void snd_pcm_system_tick_set(struct snd_pcm_substream *substream, 
				    unsigned long ticks)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	if (ticks == 0)
		del_timer(&runtime->tick_timer);
	else {
		ticks += (1000000 / HZ) - 1;
		ticks /= (1000000 / HZ);
		mod_timer(&runtime->tick_timer, jiffies + ticks);
	}
}

/* Temporary alias */
void snd_pcm_tick_set(struct snd_pcm_substream *substream, unsigned long ticks)
{
	snd_pcm_system_tick_set(substream, ticks);
}

void snd_pcm_tick_prepare(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	snd_pcm_uframes_t frames = ULONG_MAX;
	snd_pcm_uframes_t avail, dist;
	unsigned int ticks;
	u_int64_t n;
	u_int32_t r;
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
		if (runtime->silence_size >= runtime->boundary) {
			frames = 1;
		} else if (runtime->silence_size > 0 &&
			   runtime->silence_filled < runtime->buffer_size) {
			snd_pcm_sframes_t noise_dist;
			noise_dist = snd_pcm_playback_hw_avail(runtime) + runtime->silence_filled;
			if (noise_dist > (snd_pcm_sframes_t)runtime->silence_threshold)
				frames = noise_dist - runtime->silence_threshold;
		}
		avail = snd_pcm_playback_avail(runtime);
	} else {
		avail = snd_pcm_capture_avail(runtime);
	}
	if (avail < runtime->control->avail_min) {
		snd_pcm_sframes_t n = runtime->control->avail_min - avail;
		if (n > 0 && frames > (snd_pcm_uframes_t)n)
			frames = n;
	}
	if (avail < runtime->buffer_size) {
		snd_pcm_sframes_t n = runtime->buffer_size - avail;
		if (n > 0 && frames > (snd_pcm_uframes_t)n)
			frames = n;
	}
	if (frames == ULONG_MAX) {
		snd_pcm_tick_set(substream, 0);
		return;
	}
	dist = runtime->status->hw_ptr - runtime->hw_ptr_base;
	/* Distance to next interrupt */
	dist = runtime->period_size - dist % runtime->period_size;
	if (dist <= frames) {
		snd_pcm_tick_set(substream, 0);
		return;
	}
	/* the base time is us */
	n = frames;
	n *= 1000000;
	div64_32(&n, runtime->tick_time * runtime->rate, &r);
	ticks = n + (r > 0 ? 1 : 0);
	if (ticks < runtime->sleep_min)
		ticks = runtime->sleep_min;
	snd_pcm_tick_set(substream, (unsigned long) ticks);
}

void snd_pcm_tick_elapsed(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime;
	unsigned long flags;
	
	snd_assert(substream != NULL, return);
	runtime = substream->runtime;
	snd_assert(runtime != NULL, return);

	snd_pcm_stream_lock_irqsave(substream, flags);
	if (!snd_pcm_running(substream) ||
	    snd_pcm_update_hw_ptr(substream) < 0)
		goto _end;
	if (runtime->sleep_min)
		snd_pcm_tick_prepare(substream);
 _end:
	snd_pcm_stream_unlock_irqrestore(substream, flags);
}

/**
 * snd_pcm_period_elapsed - update the pcm status for the next period
 * @substream: the pcm substream instance
 *
 * This function is called from the interrupt handler when the
 * PCM has processed the period size.  It will update the current
 * pointer, set up the tick, wake up sleepers, etc.
 *
 * Even if more than one periods have elapsed since the last call, you
 * have to call this only once.
 */
void snd_pcm_period_elapsed(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime;
	unsigned long flags;

	snd_assert(substream != NULL, return);
	runtime = substream->runtime;
	snd_assert(runtime != NULL, return);

	if (runtime->transfer_ack_begin)
		runtime->transfer_ack_begin(substream);

	snd_pcm_stream_lock_irqsave(substream, flags);
	if (!snd_pcm_running(substream) ||
	    snd_pcm_update_hw_ptr_interrupt(substream) < 0)
		goto _end;

	if (substream->timer_running)
		snd_timer_interrupt(substream->timer, 1);
	if (runtime->sleep_min)
		snd_pcm_tick_prepare(substream);
 _end:
	snd_pcm_stream_unlock_irqrestore(substream, flags);
	if (runtime->transfer_ack_end)
		runtime->transfer_ack_end(substream);
	kill_fasync(&runtime->fasync, SIGIO, POLL_IN);
}

EXPORT_SYMBOL(snd_pcm_period_elapsed);

static int snd_pcm_lib_write_transfer(struct snd_pcm_substream *substream,
				      unsigned int hwoff,
				      unsigned long data, unsigned int off,
				      snd_pcm_uframes_t frames)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	int err;
	char __user *buf = (char __user *) data + frames_to_bytes(runtime, off);
	if (substream->ops->copy) {
		if ((err = substream->ops->copy(substream, -1, hwoff, buf, frames)) < 0)