usbaudio.c

linux 内核源代码

		}
		ep &= USB_ENDPOINT_NUMBER_MASK;
		if (is_playback)
			subs->syncpipe = usb_rcvisocpipe(dev, ep);
		else
			subs->syncpipe = usb_sndisocpipe(dev, ep);
		if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
		    get_endpoint(alts, 1)->bRefresh >= 1 &&
		    get_endpoint(alts, 1)->bRefresh <= 9)
			subs->syncinterval = get_endpoint(alts, 1)->bRefresh;
		else if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
			subs->syncinterval = 1;
		else if (get_endpoint(alts, 1)->bInterval >= 1 &&
			 get_endpoint(alts, 1)->bInterval <= 16)
			subs->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
		else
			subs->syncinterval = 3;
	}

	/* always fill max packet size */
	if (fmt->attributes & EP_CS_ATTR_FILL_MAX)
		subs->fill_max = 1;

	if ((err = init_usb_pitch(dev, subs->interface, alts, fmt)) < 0)
		return err;

	subs->cur_audiofmt = fmt;

#if 0
	printk("setting done: format = %d, rate = %d, channels = %d\n",
	       fmt->format, fmt->rate, fmt->channels);
	printk("  datapipe = 0x%0x, syncpipe = 0x%0x\n",
	       subs->datapipe, subs->syncpipe);
#endif

	return 0;
}

/*
 * hw_params callback
 *
 * allocate a buffer and set the given audio format.
 *
 * so far we use a physically linear buffer although packetize transfer
 * doesn't need a continuous area.
 * if sg buffer is supported on the later version of alsa, we'll follow
 * that.
 */
static int snd_usb_hw_params(struct snd_pcm_substream *substream,
			     struct snd_pcm_hw_params *hw_params)
{
	struct snd_usb_substream *subs = substream->runtime->private_data;
	struct audioformat *fmt;
	unsigned int channels, rate, format;
	int ret, changed;

	ret = snd_pcm_alloc_vmalloc_buffer(substream,
					   params_buffer_bytes(hw_params));
	if (ret < 0)
		return ret;

	format = params_format(hw_params);
	rate = params_rate(hw_params);
	channels = params_channels(hw_params);
	fmt = find_format(subs, format, rate, channels);
	if (! fmt) {
		snd_printd(KERN_DEBUG "cannot set format: format = 0x%x, rate = %d, channels = %d\n",
			   format, rate, channels);
		return -EINVAL;
	}

	changed = subs->cur_audiofmt != fmt ||
		subs->period_bytes != params_period_bytes(hw_params) ||
		subs->cur_rate != rate;
	if ((ret = set_format(subs, fmt)) < 0)
		return ret;

	if (subs->cur_rate != rate) {
		struct usb_host_interface *alts;
		struct usb_interface *iface;
		iface = usb_ifnum_to_if(subs->dev, fmt->iface);
		alts = &iface->altsetting[fmt->altset_idx];
		ret = init_usb_sample_rate(subs->dev, subs->interface, alts, fmt, rate);
		if (ret < 0)
			return ret;
		subs->cur_rate = rate;
	}

	if (changed) {
		/* format changed */
		release_substream_urbs(subs, 0);
		/* influenced: period_bytes, channels, rate, format, */
		ret = init_substream_urbs(subs, params_period_bytes(hw_params),
					  params_rate(hw_params),
					  snd_pcm_format_physical_width(params_format(hw_params)) * params_channels(hw_params));
	}

	return ret;
}

/*
 * hw_free callback
 *
 * reset the audio format and release the buffer
 */
static int snd_usb_hw_free(struct snd_pcm_substream *substream)
{
	struct snd_usb_substream *subs = substream->runtime->private_data;

	subs->cur_audiofmt = NULL;
	subs->cur_rate = 0;
	subs->period_bytes = 0;
	if (!subs->stream->chip->shutdown)
		release_substream_urbs(subs, 0);
	return snd_pcm_free_vmalloc_buffer(substream);
}

/*
 * prepare callback
 *
 * only a few subtle things...
 */
static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_usb_substream *subs = runtime->private_data;

	if (! subs->cur_audiofmt) {
		snd_printk(KERN_ERR "usbaudio: no format is specified!\n");
		return -ENXIO;
	}

	/* some unit conversions in runtime */
	subs->maxframesize = bytes_to_frames(runtime, subs->maxpacksize);
	subs->curframesize = bytes_to_frames(runtime, subs->curpacksize);

	/* reset the pointer */
	subs->hwptr_done = 0;
	subs->transfer_done = 0;
	subs->phase = 0;

	/* clear urbs (to be sure) */
	deactivate_urbs(subs, 0, 1);
	wait_clear_urbs(subs);

	/* for playback, submit the URBs now; otherwise, the first hwptr_done
	 * updates for all URBs would happen at the same time when starting */
	if (subs->direction == SNDRV_PCM_STREAM_PLAYBACK) {
		subs->ops.prepare = prepare_nodata_playback_urb;
		return start_urbs(subs, runtime);
	} else
		return 0;
}

static struct snd_pcm_hardware snd_usb_hardware =
{
	.info =			SNDRV_PCM_INFO_MMAP |
				SNDRV_PCM_INFO_MMAP_VALID |
				SNDRV_PCM_INFO_BATCH |
				SNDRV_PCM_INFO_INTERLEAVED |
				SNDRV_PCM_INFO_BLOCK_TRANSFER |
				SNDRV_PCM_INFO_PAUSE,
	.buffer_bytes_max =	1024 * 1024,
	.period_bytes_min =	64,
	.period_bytes_max =	512 * 1024,
	.periods_min =		2,
	.periods_max =		1024,
};

/*
 * h/w constraints
 */

#ifdef HW_CONST_DEBUG
#define hwc_debug(fmt, args...) printk(KERN_DEBUG fmt, ##args)
#else
#define hwc_debug(fmt, args...) /**/
#endif

static int hw_check_valid_format(struct snd_pcm_hw_params *params, struct audioformat *fp)
{
	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);

	/* check the format */
	if (! snd_mask_test(fmts, fp->format)) {
		hwc_debug("   > check: no supported format %d\n", fp->format);
		return 0;
	}
	/* check the channels */
	if (fp->channels < ct->min || fp->channels > ct->max) {
		hwc_debug("   > check: no valid channels %d (%d/%d)\n", fp->channels, ct->min, ct->max);
		return 0;
	}
	/* check the rate is within the range */
	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
		hwc_debug("   > check: rate_min %d > max %d\n", fp->rate_min, it->max);
		return 0;
	}
	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
		hwc_debug("   > check: rate_max %d < min %d\n", fp->rate_max, it->min);
		return 0;
	}
	return 1;
}

static int hw_rule_rate(struct snd_pcm_hw_params *params,
			struct snd_pcm_hw_rule *rule)
{
	struct snd_usb_substream *subs = rule->private;
	struct list_head *p;
	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
	unsigned int rmin, rmax;
	int changed;

	hwc_debug("hw_rule_rate: (%d,%d)\n", it->min, it->max);
	changed = 0;
	rmin = rmax = 0;
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		if (! hw_check_valid_format(params, fp))
			continue;
		if (changed++) {
			if (rmin > fp->rate_min)
				rmin = fp->rate_min;
			if (rmax < fp->rate_max)
				rmax = fp->rate_max;
		} else {
			rmin = fp->rate_min;
			rmax = fp->rate_max;
		}
	}

	if (! changed) {
		hwc_debug("  --> get empty\n");
		it->empty = 1;
		return -EINVAL;
	}

	changed = 0;
	if (it->min < rmin) {
		it->min = rmin;
		it->openmin = 0;
		changed = 1;
	}
	if (it->max > rmax) {
		it->max = rmax;
		it->openmax = 0;
		changed = 1;
	}
	if (snd_interval_checkempty(it)) {
		it->empty = 1;
		return -EINVAL;
	}
	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
	return changed;
}


static int hw_rule_channels(struct snd_pcm_hw_params *params,
			    struct snd_pcm_hw_rule *rule)
{
	struct snd_usb_substream *subs = rule->private;
	struct list_head *p;
	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
	unsigned int rmin, rmax;
	int changed;

	hwc_debug("hw_rule_channels: (%d,%d)\n", it->min, it->max);
	changed = 0;
	rmin = rmax = 0;
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		if (! hw_check_valid_format(params, fp))
			continue;
		if (changed++) {
			if (rmin > fp->channels)
				rmin = fp->channels;
			if (rmax < fp->channels)
				rmax = fp->channels;
		} else {
			rmin = fp->channels;
			rmax = fp->channels;
		}
	}

	if (! changed) {
		hwc_debug("  --> get empty\n");
		it->empty = 1;
		return -EINVAL;
	}

	changed = 0;
	if (it->min < rmin) {
		it->min = rmin;
		it->openmin = 0;
		changed = 1;
	}
	if (it->max > rmax) {
		it->max = rmax;
		it->openmax = 0;
		changed = 1;
	}
	if (snd_interval_checkempty(it)) {
		it->empty = 1;
		return -EINVAL;
	}
	hwc_debug("  --> (%d, %d) (changed = %d)\n", it->min, it->max, changed);
	return changed;
}

static int hw_rule_format(struct snd_pcm_hw_params *params,
			  struct snd_pcm_hw_rule *rule)
{
	struct snd_usb_substream *subs = rule->private;
	struct list_head *p;
	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
	u64 fbits;
	u32 oldbits[2];
	int changed;

	hwc_debug("hw_rule_format: %x:%x\n", fmt->bits[0], fmt->bits[1]);
	fbits = 0;
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		if (! hw_check_valid_format(params, fp))
			continue;
		fbits |= (1ULL << fp->format);
	}

	oldbits[0] = fmt->bits[0];
	oldbits[1] = fmt->bits[1];
	fmt->bits[0] &= (u32)fbits;
	fmt->bits[1] &= (u32)(fbits >> 32);
	if (! fmt->bits[0] && ! fmt->bits[1]) {
		hwc_debug("  --> get empty\n");
		return -EINVAL;
	}
	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
	hwc_debug("  --> %x:%x (changed = %d)\n", fmt->bits[0], fmt->bits[1], changed);
	return changed;
}

#define MAX_MASK	64

/*
 * check whether the registered audio formats need special hw-constraints
 */
static int check_hw_params_convention(struct snd_usb_substream *subs)
{
	int i;
	u32 *channels;
	u32 *rates;
	u32 cmaster, rmaster;
	u32 rate_min = 0, rate_max = 0;
	struct list_head *p;
	int err = 1;

	channels = kcalloc(MAX_MASK, sizeof(u32), GFP_KERNEL);
	rates = kcalloc(MAX_MASK, sizeof(u32), GFP_KERNEL);

	list_for_each(p, &subs->fmt_list) {
		struct audioformat *f;
		f = list_entry(p, struct audioformat, list);
		/* unconventional channels? */
		if (f->channels > 32)
			goto __out;
		/* continuous rate min/max matches? */
		if (f->rates & SNDRV_PCM_RATE_CONTINUOUS) {
			if (rate_min && f->rate_min != rate_min)
				goto __out;
			if (rate_max && f->rate_max != rate_max)
				goto __out;
			rate_min = f->rate_min;
			rate_max = f->rate_max;
		}
		/* combination of continuous rates and fixed rates? */
		if (rates[f->format] & SNDRV_PCM_RATE_CONTINUOUS) {
			if (f->rates != rates[f->format])
				goto __out;
		}
		if (f->rates & SNDRV_PCM_RATE_CONTINUOUS) {
			if (rates[f->format] && rates[f->format] != f->rates)
				goto __out;
		}
		channels[f->format] |= (1 << f->channels);
		rates[f->format] |= f->rates;
		/* needs knot? */
		if (f->rates & SNDRV_PCM_RATE_KNOT)
			goto __out;
	}
	/* check whether channels and rates match for all formats */
	cmaster = rmaster = 0;
	for (i = 0; i < MAX_MASK; i++) {
		if (cmaster != channels[i] && cmaster && channels[i])
			goto __out;
		if (rmaster != rates[i] && rmaster && rates[i])
			goto __out;
		if (channels[i])
			cmaster = channels[i];
		if (rates[i])
			rmaster = rates[i];
	}
	/* check whether channels match for all distinct rates */
	memset(channels, 0, MAX_MASK * sizeof(u32));
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *f;
		f = list_entry(p, struct audioformat, list);
		if (f->rates & SNDRV_PCM_RATE_CONTINUOUS)
			continue;
		for (i = 0; i < 32; i++) {
			if (f->rates & (1 << i))
				channels[i] |= (1 << f->channels);
		}
	}
	cmaster = 0;
	for (i = 0; i < 32; i++) {
		if (cmaster != channels[i] && cmaster && channels[i])
			goto __out;
		if (channels[i])
			cmaster = channels[i];
	}
	err = 0;

 __out:
	kfree(channels);
	kfree(rates);
	return err;
}

/*
 *  If the device supports unusual bit rates, does the request meet these?
 */
static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
				  struct snd_usb_substream *subs)
{
	struct audioformat *fp;
	int count = 0, needs_knot = 0;
	int err;

	list_for_each_entry(fp, &subs->fmt_list, list) {
		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
			return 0;
		count += fp->nr_rates;
		if (fp->rates & SNDRV_PCM_RATE_KNOT)
			needs_knot = 1;
	}
	if (!needs_knot)
		return 0;

	subs->rate_list.count = count;
	subs->rate_list.list = kmalloc(sizeof(int) * count, GFP_KERNEL);
	subs->rate_list.mask = 0;
	count = 0;