pcm_oss.c

linux 内核源代码

	else
		v = snd_pcm_hw_param_first(pcm, params, var, dir);
	snd_assert(v >= 0, return -EINVAL);
	return v;
}

static int _snd_pcm_hw_param_set(struct snd_pcm_hw_params *params,
				 snd_pcm_hw_param_t var, unsigned int val,
				 int dir)
{
	int changed;
	if (hw_is_mask(var)) {
		struct snd_mask *m = hw_param_mask(params, var);
		if (val == 0 && dir < 0) {
			changed = -EINVAL;
			snd_mask_none(m);
		} else {
			if (dir > 0)
				val++;
			else if (dir < 0)
				val--;
			changed = snd_mask_refine_set(hw_param_mask(params, var), val);
		}
	} else if (hw_is_interval(var)) {
		struct snd_interval *i = hw_param_interval(params, var);
		if (val == 0 && dir < 0) {
			changed = -EINVAL;
			snd_interval_none(i);
		} else if (dir == 0)
			changed = snd_interval_refine_set(i, val);
		else {
			struct snd_interval t;
			t.openmin = 1;
			t.openmax = 1;
			t.empty = 0;
			t.integer = 0;
			if (dir < 0) {
				t.min = val - 1;
				t.max = val;
			} else {
				t.min = val;
				t.max = val+1;
			}
			changed = snd_interval_refine(i, &t);
		}
	} else
		return -EINVAL;
	if (changed) {
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	}
	return changed;
}

/**
 * snd_pcm_hw_param_set
 * @pcm: PCM instance
 * @params: the hw_params instance
 * @var: parameter to retrieve
 * @val: value to set
 * @dir: pointer to the direction (-1,0,1) or NULL
 *
 * Inside configuration space defined by PARAMS remove from PAR all 
 * values != VAL. Reduce configuration space accordingly.
 *  Return VAL or -EINVAL if the configuration space is empty
 */
static int snd_pcm_hw_param_set(struct snd_pcm_substream *pcm,
				struct snd_pcm_hw_params *params,
				snd_pcm_hw_param_t var, unsigned int val,
				int dir)
{
	int changed = _snd_pcm_hw_param_set(params, var, val, dir);
	if (changed < 0)
		return changed;
	if (params->rmask) {
		int err = snd_pcm_hw_refine(pcm, params);
		if (err < 0)
			return err;
	}
	return snd_pcm_hw_param_value(params, var, NULL);
}

static int _snd_pcm_hw_param_setinteger(struct snd_pcm_hw_params *params,
					snd_pcm_hw_param_t var)
{
	int changed;
	changed = snd_interval_setinteger(hw_param_interval(params, var));
	if (changed) {
		params->cmask |= 1 << var;
		params->rmask |= 1 << var;
	}
	return changed;
}
	
/*
 * plugin
 */

#ifdef CONFIG_SND_PCM_OSS_PLUGINS
static int snd_pcm_oss_plugin_clear(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_pcm_plugin *plugin, *next;
	
	plugin = runtime->oss.plugin_first;
	while (plugin) {
		next = plugin->next;
		snd_pcm_plugin_free(plugin);
		plugin = next;
	}
	runtime->oss.plugin_first = runtime->oss.plugin_last = NULL;
	return 0;
}

static int snd_pcm_plugin_insert(struct snd_pcm_plugin *plugin)
{
	struct snd_pcm_runtime *runtime = plugin->plug->runtime;
	plugin->next = runtime->oss.plugin_first;
	plugin->prev = NULL;
	if (runtime->oss.plugin_first) {
		runtime->oss.plugin_first->prev = plugin;
		runtime->oss.plugin_first = plugin;
	} else {
		runtime->oss.plugin_last =
		runtime->oss.plugin_first = plugin;
	}
	return 0;
}

int snd_pcm_plugin_append(struct snd_pcm_plugin *plugin)
{
	struct snd_pcm_runtime *runtime = plugin->plug->runtime;
	plugin->next = NULL;
	plugin->prev = runtime->oss.plugin_last;
	if (runtime->oss.plugin_last) {
		runtime->oss.plugin_last->next = plugin;
		runtime->oss.plugin_last = plugin;
	} else {
		runtime->oss.plugin_last =
		runtime->oss.plugin_first = plugin;
	}
	return 0;
}
#endif /* CONFIG_SND_PCM_OSS_PLUGINS */

static long snd_pcm_oss_bytes(struct snd_pcm_substream *substream, long frames)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	long buffer_size = snd_pcm_lib_buffer_bytes(substream);
	long bytes = frames_to_bytes(runtime, frames);
	if (buffer_size == runtime->oss.buffer_bytes)
		return bytes;
#if BITS_PER_LONG >= 64
	return runtime->oss.buffer_bytes * bytes / buffer_size;
#else
	{
		u64 bsize = (u64)runtime->oss.buffer_bytes * (u64)bytes;
		u32 rem;
		div64_32(&bsize, buffer_size, &rem);
		return (long)bsize;
	}
#endif
}

static long snd_pcm_alsa_frames(struct snd_pcm_substream *substream, long bytes)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	long buffer_size = snd_pcm_lib_buffer_bytes(substream);
	if (buffer_size == runtime->oss.buffer_bytes)
		return bytes_to_frames(runtime, bytes);
	return bytes_to_frames(runtime, (buffer_size * bytes) / runtime->oss.buffer_bytes);
}

/* define extended formats in the recent OSS versions (if any) */
/* linear formats */
#define AFMT_S32_LE      0x00001000
#define AFMT_S32_BE      0x00002000
#define AFMT_S24_LE      0x00008000
#define AFMT_S24_BE      0x00010000
#define AFMT_S24_PACKED  0x00040000

/* other supported formats */
#define AFMT_FLOAT       0x00004000
#define AFMT_SPDIF_RAW   0x00020000

/* unsupported formats */
#define AFMT_AC3         0x00000400
#define AFMT_VORBIS      0x00000800

static int snd_pcm_oss_format_from(int format)
{
	switch (format) {
	case AFMT_MU_LAW:	return SNDRV_PCM_FORMAT_MU_LAW;
	case AFMT_A_LAW:	return SNDRV_PCM_FORMAT_A_LAW;
	case AFMT_IMA_ADPCM:	return SNDRV_PCM_FORMAT_IMA_ADPCM;
	case AFMT_U8:		return SNDRV_PCM_FORMAT_U8;
	case AFMT_S16_LE:	return SNDRV_PCM_FORMAT_S16_LE;
	case AFMT_S16_BE:	return SNDRV_PCM_FORMAT_S16_BE;
	case AFMT_S8:		return SNDRV_PCM_FORMAT_S8;
	case AFMT_U16_LE:	return SNDRV_PCM_FORMAT_U16_LE;
	case AFMT_U16_BE:	return SNDRV_PCM_FORMAT_U16_BE;
	case AFMT_MPEG:		return SNDRV_PCM_FORMAT_MPEG;
	case AFMT_S32_LE:	return SNDRV_PCM_FORMAT_S32_LE;
	case AFMT_S32_BE:	return SNDRV_PCM_FORMAT_S32_BE;
	case AFMT_S24_LE:	return SNDRV_PCM_FORMAT_S24_LE;
	case AFMT_S24_BE:	return SNDRV_PCM_FORMAT_S24_BE;
	case AFMT_S24_PACKED:	return SNDRV_PCM_FORMAT_S24_3LE;
	case AFMT_FLOAT:	return SNDRV_PCM_FORMAT_FLOAT;
	case AFMT_SPDIF_RAW:	return SNDRV_PCM_FORMAT_IEC958_SUBFRAME;
	default:		return SNDRV_PCM_FORMAT_U8;
	}
}

static int snd_pcm_oss_format_to(int format)
{
	switch (format) {
	case SNDRV_PCM_FORMAT_MU_LAW:	return AFMT_MU_LAW;
	case SNDRV_PCM_FORMAT_A_LAW:	return AFMT_A_LAW;
	case SNDRV_PCM_FORMAT_IMA_ADPCM:	return AFMT_IMA_ADPCM;
	case SNDRV_PCM_FORMAT_U8:		return AFMT_U8;
	case SNDRV_PCM_FORMAT_S16_LE:	return AFMT_S16_LE;
	case SNDRV_PCM_FORMAT_S16_BE:	return AFMT_S16_BE;
	case SNDRV_PCM_FORMAT_S8:		return AFMT_S8;
	case SNDRV_PCM_FORMAT_U16_LE:	return AFMT_U16_LE;
	case SNDRV_PCM_FORMAT_U16_BE:	return AFMT_U16_BE;
	case SNDRV_PCM_FORMAT_MPEG:		return AFMT_MPEG;
	case SNDRV_PCM_FORMAT_S32_LE:	return AFMT_S32_LE;
	case SNDRV_PCM_FORMAT_S32_BE:	return AFMT_S32_BE;
	case SNDRV_PCM_FORMAT_S24_LE:	return AFMT_S24_LE;
	case SNDRV_PCM_FORMAT_S24_BE:	return AFMT_S24_BE;
	case SNDRV_PCM_FORMAT_S24_3LE:	return AFMT_S24_PACKED;
	case SNDRV_PCM_FORMAT_FLOAT:	return AFMT_FLOAT;
	case SNDRV_PCM_FORMAT_IEC958_SUBFRAME: return AFMT_SPDIF_RAW;
	default:			return -EINVAL;
	}
}

static int snd_pcm_oss_period_size(struct snd_pcm_substream *substream, 
				   struct snd_pcm_hw_params *oss_params,
				   struct snd_pcm_hw_params *slave_params)
{
	size_t s;
	size_t oss_buffer_size, oss_period_size, oss_periods;
	size_t min_period_size, max_period_size;
	struct snd_pcm_runtime *runtime = substream->runtime;
	size_t oss_frame_size;

	oss_frame_size = snd_pcm_format_physical_width(params_format(oss_params)) *
			 params_channels(oss_params) / 8;

	oss_buffer_size = snd_pcm_plug_client_size(substream,
						   snd_pcm_hw_param_value_max(slave_params, SNDRV_PCM_HW_PARAM_BUFFER_SIZE, NULL)) * oss_frame_size;
	oss_buffer_size = 1 << ld2(oss_buffer_size);
	if (atomic_read(&substream->mmap_count)) {
		if (oss_buffer_size > runtime->oss.mmap_bytes)
			oss_buffer_size = runtime->oss.mmap_bytes;
	}

	if (substream->oss.setup.period_size > 16)
		oss_period_size = substream->oss.setup.period_size;
	else if (runtime->oss.fragshift) {
		oss_period_size = 1 << runtime->oss.fragshift;
		if (oss_period_size > oss_buffer_size / 2)
			oss_period_size = oss_buffer_size / 2;
	} else {
		int sd;
		size_t bytes_per_sec = params_rate(oss_params) * snd_pcm_format_physical_width(params_format(oss_params)) * params_channels(oss_params) / 8;

		oss_period_size = oss_buffer_size;
		do {
			oss_period_size /= 2;
		} while (oss_period_size > bytes_per_sec);
		if (runtime->oss.subdivision == 0) {
			sd = 4;
			if (oss_period_size / sd > 4096)
				sd *= 2;
			if (oss_period_size / sd < 4096)
				sd = 1;
		} else
			sd = runtime->oss.subdivision;
		oss_period_size /= sd;
		if (oss_period_size < 16)
			oss_period_size = 16;
	}

	min_period_size = snd_pcm_plug_client_size(substream,
						   snd_pcm_hw_param_value_min(slave_params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, NULL));
	min_period_size *= oss_frame_size;
	min_period_size = 1 << (ld2(min_period_size - 1) + 1);
	if (oss_period_size < min_period_size)
		oss_period_size = min_period_size;

	max_period_size = snd_pcm_plug_client_size(substream,
						   snd_pcm_hw_param_value_max(slave_params, SNDRV_PCM_HW_PARAM_PERIOD_SIZE, NULL));
	max_period_size *= oss_frame_size;
	max_period_size = 1 << ld2(max_period_size);
	if (oss_period_size > max_period_size)
		oss_period_size = max_period_size;

	oss_periods = oss_buffer_size / oss_period_size;

	if (substream->oss.setup.periods > 1)
		oss_periods = substream->oss.setup.periods;

	s = snd_pcm_hw_param_value_max(slave_params, SNDRV_PCM_HW_PARAM_PERIODS, NULL);
	if (runtime->oss.maxfrags && s > runtime->oss.maxfrags)
		s = runtime->oss.maxfrags;
	if (oss_periods > s)
		oss_periods = s;

	s = snd_pcm_hw_param_value_min(slave_params, SNDRV_PCM_HW_PARAM_PERIODS, NULL);
	if (s < 2)
		s = 2;
	if (oss_periods < s)
		oss_periods = s;

	while (oss_period_size * oss_periods > oss_buffer_size)
		oss_period_size /= 2;

	snd_assert(oss_period_size >= 16, return -EINVAL);
	runtime->oss.period_bytes = oss_period_size;
	runtime->oss.period_frames = 1;
	runtime->oss.periods = oss_periods;
	return 0;
}

static int choose_rate(struct snd_pcm_substream *substream,
		       struct snd_pcm_hw_params *params, unsigned int best_rate)
{
	struct snd_interval *it;
	struct snd_pcm_hw_params *save;
	unsigned int rate, prev;

	save = kmalloc(sizeof(*save), GFP_KERNEL);
	if (save == NULL)
		return -ENOMEM;
	*save = *params;
	it = hw_param_interval(save, SNDRV_PCM_HW_PARAM_RATE);

	/* try multiples of the best rate */
	rate = best_rate;
	for (;;) {
		if (it->max < rate || (it->max == rate && it->openmax))
			break;
		if (it->min < rate || (it->min == rate && !it->openmin)) {
			int ret;
			ret = snd_pcm_hw_param_set(substream, params,
						   SNDRV_PCM_HW_PARAM_RATE,
						   rate, 0);
			if (ret == (int)rate) {
				kfree(save);
				return rate;
			}
			*params = *save;
		}
		prev = rate;
		rate += best_rate;
		if (rate <= prev)
			break;
	}

	/* not found, use the nearest rate */
	kfree(save);
	return snd_pcm_hw_param_near(substream, params, SNDRV_PCM_HW_PARAM_RATE, best_rate, NULL);
}

static int snd_pcm_oss_change_params(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_pcm_hw_params *params, *sparams;
	struct snd_pcm_sw_params *sw_params;
	ssize_t oss_buffer_size, oss_period_size;
	size_t oss_frame_size;
	int err;
	int direct;
	int format, sformat, n;
	struct snd_mask sformat_mask;
	struct snd_mask mask;

	if (mutex_lock_interruptible(&runtime->oss.params_lock))
		return -EINTR;
	sw_params = kmalloc(sizeof(*sw_params), GFP_KERNEL);
	params = kmalloc(sizeof(*params), GFP_KERNEL);
	sparams = kmalloc(sizeof(*sparams), GFP_KERNEL);
	if (!sw_params || !params || !sparams) {
		snd_printd("No memory\n");
		err = -ENOMEM;
		goto failure;
	}

	if (atomic_read(&substream->mmap_count))
		direct = 1;
	else
		direct = substream->oss.setup.direct;

	_snd_pcm_hw_params_any(sparams);
	_snd_pcm_hw_param_setinteger(sparams, SNDRV_PCM_HW_PARAM_PERIODS);
	_snd_pcm_hw_param_min(sparams, SNDRV_PCM_HW_PARAM_PERIODS, 2, 0);
	snd_mask_none(&mask);
	if (atomic_read(&substream->mmap_count))
		snd_mask_set(&mask, SNDRV_PCM_ACCESS_MMAP_INTERLEAVED);
	else {
		snd_mask_set(&mask, SNDRV_PCM_ACCESS_RW_INTERLEAVED);
		if (!direct)
			snd_mask_set(&mask, SNDRV_PCM_ACCESS_RW_NONINTERLEAVED);
	}
	err = snd_pcm_hw_param_mask(substream, sparams, SNDRV_PCM_HW_PARAM_ACCESS, &mask);
	if (err < 0) {
		snd_printd("No usable accesses\n");
		err = -EINVAL;
		goto failure;
	}
	choose_rate(substream, sparams, runtime->oss.rate);
	snd_pcm_hw_param_near(substream, sparams, SNDRV_PCM_HW_PARAM_CHANNELS, runtime->oss.channels, NULL);

	format = snd_pcm_oss_format_from(runtime->oss.format);

	sformat_mask = *hw_param_mask(sparams, SNDRV_PCM_HW_PARAM_FORMAT);
	if (direct)
		sformat = format;
	else
		sformat = snd_pcm_plug_slave_format(format, &sformat_mask);

	if (sformat < 0 || !snd_mask_test(&sformat_mask, sformat)) {
		for (sformat = 0; sformat <= SNDRV_PCM_FORMAT_LAST; sformat++) {
			if (snd_mask_test(&sformat_mask, sformat) &&
			    snd_pcm_oss_format_to(sformat) >= 0)
				break;
		}
		if (sformat > SNDRV_PCM_FORMAT_LAST) {
			snd_printd("Cannot find a format!!!\n");
			err = -EINVAL;
			goto failure;
		}
	}
	err = _snd_pcm_hw_param_set(sparams, SNDRV_PCM_HW_PARAM_FORMAT, sformat, 0);
	snd_assert(err >= 0, goto failure);

	if (direct) {
		memcpy(params, sparams, sizeof(*params));
	} else {
		_snd_pcm_hw_params_any(params);
		_snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_ACCESS,
				      SNDRV_PCM_ACCESS_RW_INTERLEAVED, 0);
		_snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_FORMAT,
				      snd_pcm_oss_format_from(runtime->oss.format), 0);
		_snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_CHANNELS,
				      runtime->oss.channels, 0);
		_snd_pcm_hw_param_set(params, SNDRV_PCM_HW_PARAM_RATE,
				      runtime->oss.rate, 0);
		pdprintf("client: access = %i, format = %i, channels = %i, rate = %i\n",
			 params_access(params), params_format(params),
			 params_channels(params), params_rate(params));
	}
	pdprintf("slave: access = %i, format = %i, channels = %i, rate = %i\n",
		 params_access(sparams), params_format(sparams),
		 params_channels(sparams), params_rate(sparams));

	oss_frame_size = snd_pcm_format_physical_width(params_format(params)) *
			 params_channels(params) / 8;

#ifdef CONFIG_SND_PCM_OSS_PLUGINS