usbaudio.c

linux 内核源代码

	list_for_each_entry(fp, &subs->fmt_list, list) {
		int i;
		for (i = 0; i < fp->nr_rates; i++)
			subs->rate_list.list[count++] = fp->rate_table[i];
	}
	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
					 &subs->rate_list);
	if (err < 0)
		return err;

	return 0;
}


/*
 * set up the runtime hardware information.
 */

static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
{
	struct list_head *p;
	int err;

	runtime->hw.formats = subs->formats;

	runtime->hw.rate_min = 0x7fffffff;
	runtime->hw.rate_max = 0;
	runtime->hw.channels_min = 256;
	runtime->hw.channels_max = 0;
	runtime->hw.rates = 0;
	/* check min/max rates and channels */
	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		runtime->hw.rates |= fp->rates;
		if (runtime->hw.rate_min > fp->rate_min)
			runtime->hw.rate_min = fp->rate_min;
		if (runtime->hw.rate_max < fp->rate_max)
			runtime->hw.rate_max = fp->rate_max;
		if (runtime->hw.channels_min > fp->channels)
			runtime->hw.channels_min = fp->channels;
		if (runtime->hw.channels_max < fp->channels)
			runtime->hw.channels_max = fp->channels;
		if (fp->fmt_type == USB_FORMAT_TYPE_II && fp->frame_size > 0) {
			/* FIXME: there might be more than one audio formats... */
			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
				fp->frame_size;
		}
	}

	/* set the period time minimum 1ms */
	/* FIXME: high-speed mode allows 125us minimum period, but many parts
	 * in the current code assume the 1ms period.
	 */
	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
				     1000 * MIN_PACKS_URB,
				     /*(nrpacks * MAX_URBS) * 1000*/ UINT_MAX);

	if (check_hw_params_convention(subs)) {
		hwc_debug("setting extra hw constraints...\n");
		if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
					       hw_rule_rate, subs,
					       SNDRV_PCM_HW_PARAM_FORMAT,
					       SNDRV_PCM_HW_PARAM_CHANNELS,
					       -1)) < 0)
			return err;
		if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
					       hw_rule_channels, subs,
					       SNDRV_PCM_HW_PARAM_FORMAT,
					       SNDRV_PCM_HW_PARAM_RATE,
					       -1)) < 0)
			return err;
		if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
					       hw_rule_format, subs,
					       SNDRV_PCM_HW_PARAM_RATE,
					       SNDRV_PCM_HW_PARAM_CHANNELS,
					       -1)) < 0)
			return err;
		if ((err = snd_usb_pcm_check_knot(runtime, subs)) < 0)
			return err;
	}
	return 0;
}

static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
{
	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_usb_substream *subs = &as->substream[direction];

	subs->interface = -1;
	subs->format = 0;
	runtime->hw = snd_usb_hardware;
	runtime->private_data = subs;
	subs->pcm_substream = substream;
	return setup_hw_info(runtime, subs);
}

static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
{
	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
	struct snd_usb_substream *subs = &as->substream[direction];

	if (subs->interface >= 0) {
		usb_set_interface(subs->dev, subs->interface, 0);
		subs->interface = -1;
	}
	subs->pcm_substream = NULL;
	return 0;
}

static int snd_usb_playback_open(struct snd_pcm_substream *substream)
{
	return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_PLAYBACK);
}

static int snd_usb_playback_close(struct snd_pcm_substream *substream)
{
	return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_PLAYBACK);
}

static int snd_usb_capture_open(struct snd_pcm_substream *substream)
{
	return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_CAPTURE);
}

static int snd_usb_capture_close(struct snd_pcm_substream *substream)
{
	return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_CAPTURE);
}

static struct snd_pcm_ops snd_usb_playback_ops = {
	.open =		snd_usb_playback_open,
	.close =	snd_usb_playback_close,
	.ioctl =	snd_pcm_lib_ioctl,
	.hw_params =	snd_usb_hw_params,
	.hw_free =	snd_usb_hw_free,
	.prepare =	snd_usb_pcm_prepare,
	.trigger =	snd_usb_pcm_playback_trigger,
	.pointer =	snd_usb_pcm_pointer,
	.page =		snd_pcm_get_vmalloc_page,
};

static struct snd_pcm_ops snd_usb_capture_ops = {
	.open =		snd_usb_capture_open,
	.close =	snd_usb_capture_close,
	.ioctl =	snd_pcm_lib_ioctl,
	.hw_params =	snd_usb_hw_params,
	.hw_free =	snd_usb_hw_free,
	.prepare =	snd_usb_pcm_prepare,
	.trigger =	snd_usb_pcm_capture_trigger,
	.pointer =	snd_usb_pcm_pointer,
	.page =		snd_pcm_get_vmalloc_page,
};



/*
 * helper functions
 */

/*
 * combine bytes and get an integer value
 */
unsigned int snd_usb_combine_bytes(unsigned char *bytes, int size)
{
	switch (size) {
	case 1:  return *bytes;
	case 2:  return combine_word(bytes);
	case 3:  return combine_triple(bytes);
	case 4:  return combine_quad(bytes);
	default: return 0;
	}
}

/*
 * parse descriptor buffer and return the pointer starting the given
 * descriptor type.
 */
void *snd_usb_find_desc(void *descstart, int desclen, void *after, u8 dtype)
{
	u8 *p, *end, *next;

	p = descstart;
	end = p + desclen;
	for (; p < end;) {
		if (p[0] < 2)
			return NULL;
		next = p + p[0];
		if (next > end)
			return NULL;
		if (p[1] == dtype && (!after || (void *)p > after)) {
			return p;
		}
		p = next;
	}
	return NULL;
}

/*
 * find a class-specified interface descriptor with the given subtype.
 */
void *snd_usb_find_csint_desc(void *buffer, int buflen, void *after, u8 dsubtype)
{
	unsigned char *p = after;

	while ((p = snd_usb_find_desc(buffer, buflen, p,
				      USB_DT_CS_INTERFACE)) != NULL) {
		if (p[0] >= 3 && p[2] == dsubtype)
			return p;
	}
	return NULL;
}

/*
 * Wrapper for usb_control_msg().
 * Allocates a temp buffer to prevent dmaing from/to the stack.
 */
int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, __u8 request,
		    __u8 requesttype, __u16 value, __u16 index, void *data,
		    __u16 size, int timeout)
{
	int err;
	void *buf = NULL;

	if (size > 0) {
		buf = kmemdup(data, size, GFP_KERNEL);
		if (!buf)
			return -ENOMEM;
	}
	err = usb_control_msg(dev, pipe, request, requesttype,
			      value, index, buf, size, timeout);
	if (size > 0) {
		memcpy(data, buf, size);
		kfree(buf);
	}
	return err;
}


/*
 * entry point for linux usb interface
 */

static int usb_audio_probe(struct usb_interface *intf,
			   const struct usb_device_id *id);
static void usb_audio_disconnect(struct usb_interface *intf);

static struct usb_device_id usb_audio_ids [] = {
#include "usbquirks.h"
    { .match_flags = (USB_DEVICE_ID_MATCH_INT_CLASS | USB_DEVICE_ID_MATCH_INT_SUBCLASS),
      .bInterfaceClass = USB_CLASS_AUDIO,
      .bInterfaceSubClass = USB_SUBCLASS_AUDIO_CONTROL },
    { }						/* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, usb_audio_ids);

static struct usb_driver usb_audio_driver = {
	.name =		"snd-usb-audio",
	.probe =	usb_audio_probe,
	.disconnect =	usb_audio_disconnect,
	.id_table =	usb_audio_ids,
};


#if defined(CONFIG_PROC_FS) && defined(CONFIG_SND_VERBOSE_PROCFS)

/*
 * proc interface for list the supported pcm formats
 */
static void proc_dump_substream_formats(struct snd_usb_substream *subs, struct snd_info_buffer *buffer)
{
	struct list_head *p;
	static char *sync_types[4] = {
		"NONE", "ASYNC", "ADAPTIVE", "SYNC"
	};

	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		snd_iprintf(buffer, "  Interface %d\n", fp->iface);
		snd_iprintf(buffer, "    Altset %d\n", fp->altsetting);
		snd_iprintf(buffer, "    Format: 0x%x\n", fp->format);
		snd_iprintf(buffer, "    Channels: %d\n", fp->channels);
		snd_iprintf(buffer, "    Endpoint: %d %s (%s)\n",
			    fp->endpoint & USB_ENDPOINT_NUMBER_MASK,
			    fp->endpoint & USB_DIR_IN ? "IN" : "OUT",
			    sync_types[(fp->ep_attr & EP_ATTR_MASK) >> 2]);
		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS) {
			snd_iprintf(buffer, "    Rates: %d - %d (continuous)\n",
				    fp->rate_min, fp->rate_max);
		} else {
			unsigned int i;
			snd_iprintf(buffer, "    Rates: ");
			for (i = 0; i < fp->nr_rates; i++) {
				if (i > 0)
					snd_iprintf(buffer, ", ");
				snd_iprintf(buffer, "%d", fp->rate_table[i]);
			}
			snd_iprintf(buffer, "\n");
		}
		// snd_iprintf(buffer, "    Max Packet Size = %d\n", fp->maxpacksize);
		// snd_iprintf(buffer, "    EP Attribute = 0x%x\n", fp->attributes);
	}
}

static void proc_dump_substream_status(struct snd_usb_substream *subs, struct snd_info_buffer *buffer)
{
	if (subs->running) {
		unsigned int i;
		snd_iprintf(buffer, "  Status: Running\n");
		snd_iprintf(buffer, "    Interface = %d\n", subs->interface);
		snd_iprintf(buffer, "    Altset = %d\n", subs->format);
		snd_iprintf(buffer, "    URBs = %d [ ", subs->nurbs);
		for (i = 0; i < subs->nurbs; i++)
			snd_iprintf(buffer, "%d ", subs->dataurb[i].packets);
		snd_iprintf(buffer, "]\n");
		snd_iprintf(buffer, "    Packet Size = %d\n", subs->curpacksize);
		snd_iprintf(buffer, "    Momentary freq = %u Hz (%#x.%04x)\n",
			    snd_usb_get_speed(subs->dev) == USB_SPEED_FULL
			    ? get_full_speed_hz(subs->freqm)
			    : get_high_speed_hz(subs->freqm),
			    subs->freqm >> 16, subs->freqm & 0xffff);
	} else {
		snd_iprintf(buffer, "  Status: Stop\n");
	}
}

static void proc_pcm_format_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
{
	struct snd_usb_stream *stream = entry->private_data;

	snd_iprintf(buffer, "%s : %s\n", stream->chip->card->longname, stream->pcm->name);

	if (stream->substream[SNDRV_PCM_STREAM_PLAYBACK].num_formats) {
		snd_iprintf(buffer, "\nPlayback:\n");
		proc_dump_substream_status(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
		proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_PLAYBACK], buffer);
	}
	if (stream->substream[SNDRV_PCM_STREAM_CAPTURE].num_formats) {
		snd_iprintf(buffer, "\nCapture:\n");
		proc_dump_substream_status(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
		proc_dump_substream_formats(&stream->substream[SNDRV_PCM_STREAM_CAPTURE], buffer);
	}
}

static void proc_pcm_format_add(struct snd_usb_stream *stream)
{
	struct snd_info_entry *entry;
	char name[32];
	struct snd_card *card = stream->chip->card;

	sprintf(name, "stream%d", stream->pcm_index);
	if (! snd_card_proc_new(card, name, &entry))
		snd_info_set_text_ops(entry, stream, proc_pcm_format_read);
}

#else

static inline void proc_pcm_format_add(struct snd_usb_stream *stream)
{
}

#endif

/*
 * initialize the substream instance.
 */

static void init_substream(struct snd_usb_stream *as, int stream, struct audioformat *fp)
{
	struct snd_usb_substream *subs = &as->substream[stream];

	INIT_LIST_HEAD(&subs->fmt_list);
	spin_lock_init(&subs->lock);

	subs->stream = as;
	subs->direction = stream;
	subs->dev = as->chip->dev;
	if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
		subs->ops = audio_urb_ops[stream];
	else
		subs->ops = audio_urb_ops_high_speed[stream];
	snd_pcm_set_ops(as->pcm, stream,
			stream == SNDRV_PCM_STREAM_PLAYBACK ?
			&snd_usb_playback_ops : &snd_usb_capture_ops);

	list_add_tail(&fp->list, &subs->fmt_list);
	subs->formats |= 1ULL << fp->format;
	subs->endpoint = fp->endpoint;
	subs->num_formats++;
	subs->fmt_type = fp->fmt_type;
}


/*
 * free a substream
 */
static void free_substream(struct snd_usb_substream *subs)
{
	struct list_head *p, *n;

	if (! subs->num_formats)
		return; /* not initialized */
	list_for_each_safe(p, n, &subs->fmt_list) {
		struct audioformat *fp = list_entry(p, struct audioformat, list);
		kfree(fp->rate_table);
		kfree(fp);
	}
	kfree(subs->rate_list.list);
}


/*
 * free a usb stream instance
 */
static void snd_usb_audio_stream_free(struct snd_usb_stream *stream)
{
	free_substream(&stream->substream[0]);
	free_substream(&stream->substream[1]);
	list_del(&stream->list);
	kfree(stream);
}

static void snd_usb_audio_pcm_free(struct snd_pcm *pcm)
{
	struct snd_usb_stream *stream = pcm->private_data;
	if (stream) {
		stream->pcm = NULL;
		snd_usb_audio_stream_free(stream);
	}
}


/*
 * add this endpoint to the chip instance.
 * if a stream with the same endpoint already exists, append to it.
 * if not, create a new pcm stream.
 */
static int add_audio_endpoint(struct snd_usb_audio *chip, int stream, struct audioformat *fp)
{
	struct list_head *p;
	struct snd_usb_stream *as;
	struct snd_usb_substream *subs;
	struct snd_pcm *pcm;
	int err;

	list_for_each(p, &chip->pcm_list) {
		as = list_entry(p, struct snd_usb_stream, list);
		if (as->fmt_type != fp->fmt_type)
			continue;
		subs = &as->substream[stream];