path: root/sound/usb/pcm.c

/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>

#include "usbaudio.h"
#include "card.h"
#include "quirks.h"
#include "debug.h"
#include "endpoint.h"
#include "helper.h"
#include "pcm.h"
#include "clock.h"
#include "power.h"

/* return the estimated delay based on USB frame counters */
snd_pcm_uframes_t snd_usb_pcm_delay(struct snd_usb_substream *subs,
				    unsigned int rate)
{
	int current_frame_number;
	int frame_diff;
	int est_delay;

	current_frame_number = usb_get_current_frame_number(subs->dev);
	/*
	 * HCD implementations use different widths, use lower 8 bits.
	 * The delay will be managed up to 256ms, which is more than
	 * enough
	 */
	frame_diff = (current_frame_number - subs->last_frame_number) & 0xff;

	/* Approximation based on number of samples per USB frame (ms),
	   some truncation for 44.1 but the estimate is good enough */
	est_delay =  subs->last_delay - (frame_diff * rate / 1000);
	if (est_delay < 0)
		est_delay = 0;
	return est_delay;
}

/*
 * return the current pcm pointer.  just based on the hwptr_done value.
 */
static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
{
	struct snd_usb_substream *subs;
	unsigned int hwptr_done;

	subs = (struct snd_usb_substream *)substream->runtime->private_data;
	if (subs->stream->chip->shutdown)
		return SNDRV_PCM_POS_XRUN;
	spin_lock(&subs->lock);
	hwptr_done = subs->hwptr_done;
	substream->runtime->delay = snd_usb_pcm_delay(subs,
						substream->runtime->rate);
	spin_unlock(&subs->lock);
	return hwptr_done / (substream->runtime->frame_bits >> 3);
}

/*
 * find a matching audio format
 */
static struct audioformat *find_format(struct snd_usb_substream *subs, unsigned int format,
				       unsigned int rate, unsigned int channels)
{
	struct list_head *p;
	struct audioformat *found = NULL;
	int cur_attr = 0, attr;

	list_for_each(p, &subs->fmt_list) {
		struct audioformat *fp;
		fp = list_entry(p, struct audioformat, list);
		if (!(fp->formats & (1uLL << format)))
			continue;
		if (fp->channels != channels)
			continue;
		if (rate < fp->rate_min || rate > fp->rate_max)
			continue;
		if (! (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)) {
			unsigned int i;
			for (i = 0; i < fp->nr_rates; i++)
				if (fp->rate_table[i] == rate)
					break;
			if (i >= fp->nr_rates)
				continue;
		}
		attr = fp->ep_attr & USB_ENDPOINT_SYNCTYPE;
		if (! found) {
			found = fp;
			cur_attr = attr;
			continue;
		}
		/* avoid async out and adaptive in if the other method
		 * supports the same format.
		 * this is a workaround for the case like
		 * M-audio audiophile USB.
		 */
		if (attr != cur_attr) {
			if ((attr == USB_ENDPOINT_SYNC_ASYNC &&
			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
			    (attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
			     subs->direction == SNDRV_PCM_STREAM_CAPTURE))
				continue;
			if ((cur_attr == USB_ENDPOINT_SYNC_ASYNC &&
			     subs->direction == SNDRV_PCM_STREAM_PLAYBACK) ||
			    (cur_attr == USB_ENDPOINT_SYNC_ADAPTIVE &&
			     subs->direction == SNDRV_PCM_STREAM_CAPTURE)) {
				found = fp;
				cur_attr = attr;
				continue;
			}
		}
		/* find the format with the largest max. packet size */
		if (fp->maxpacksize > found->maxpacksize) {
			found = fp;
			cur_attr = attr;
		}
	}
	return found;
}

static int init_pitch_v1(struct snd_usb_audio *chip, int iface,
			 struct usb_host_interface *alts,
			 struct audioformat *fmt)
{
	struct usb_device *dev = chip->dev;
	unsigned int ep;
	unsigned char data[1];
	int err;

	ep = get_endpoint(alts, 0)->bEndpointAddress;

	data[0] = 1;
	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
				   USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,