pcm.c

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/*
 *   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/ratelimit.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"

#define SUBSTREAM_FLAG_DATA_EP_STARTED  0
#define SUBSTREAM_FLAG_SYNC_EP_STARTED  1

/* 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)
{
    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 << subs->pcm_format)))
            continue;
        if (fp->channels != subs->channels)
            continue;
        if (subs->cur_rate < fp->rate_min ||
            subs->cur_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] == subs->cur_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,
                   UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
                   data, sizeof(data))) < 0) {
        snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH\n",
               dev->devnum, iface, ep);
        return err;
    }

    return 0;
}

static int init_pitch_v2(struct snd_usb_audio *chip, int iface,
             struct usb_host_interface *alts,
             struct audioformat *fmt)
{
    struct usb_device *dev = chip->dev;
    unsigned char data[1];
    unsigned int ep;
    int err;

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

    data[0] = 1;
    if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
                   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
                   UAC2_EP_CS_PITCH << 8, 0,
                   data, sizeof(data))) < 0) {
        snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH (v2)\n",
               dev->devnum, iface, fmt->altsetting);
        return err;
    }

    return 0;
}

/*
 * initialize the pitch control and sample rate
 */
int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,
               struct usb_host_interface *alts,
               struct audioformat *fmt)
{
    struct usb_interface_descriptor *altsd = get_iface_desc(alts);

    /* if endpoint doesn't have pitch control, bail out */
    if (!(fmt->attributes & UAC_EP_CS_ATTR_PITCH_CONTROL))
        return 0;

    switch (altsd->bInterfaceProtocol) {
    case UAC_VERSION_1:
    default:
        return init_pitch_v1(chip, iface, alts, fmt);

    case UAC_VERSION_2:
        return init_pitch_v2(chip, iface, alts, fmt);
    }
}

static int start_endpoints(struct snd_usb_substream *subs, int can_sleep)
{
    int err;

    if (!subs->data_endpoint)
        return -EINVAL;

    if (!test_and_set_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags)) {
        struct snd_usb_endpoint *ep = subs->data_endpoint;

        snd_printdd(KERN_DEBUG "Starting data EP @%p\n", ep);

        ep->data_subs = subs;
        err = snd_usb_endpoint_start(ep, can_sleep);
        if (err < 0) {
            clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags);
            return err;
        }
    }

    if (subs->sync_endpoint &&
        !test_and_set_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags)) {
        struct snd_usb_endpoint *ep = subs->sync_endpoint;

        if (subs->data_endpoint->iface != subs->sync_endpoint->iface ||
            subs->data_endpoint->alt_idx != subs->sync_endpoint->alt_idx) {
            err = usb_set_interface(subs->dev,
                        subs->sync_endpoint->iface,
                        subs->sync_endpoint->alt_idx);
            if (err < 0) {
                snd_printk(KERN_ERR
                       "%d:%d:%d: cannot set interface (%d)\n",
                       subs->dev->devnum,
                       subs->sync_endpoint->iface,
                       subs->sync_endpoint->alt_idx, err);
                return -EIO;
            }
        }

        snd_printdd(KERN_DEBUG "Starting sync EP @%p\n", ep);

        ep->sync_slave = subs->data_endpoint;
        err = snd_usb_endpoint_start(ep, can_sleep);
        if (err < 0) {
            clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags);
            return err;
        }
    }

    return 0;
}

static void stop_endpoints(struct snd_usb_substream *subs,
               int force, int can_sleep, int wait)
{
    if (test_and_clear_bit(SUBSTREAM_FLAG_SYNC_EP_STARTED, &subs->flags))
        snd_usb_endpoint_stop(subs->sync_endpoint,
                      force, can_sleep, wait);

    if (test_and_clear_bit(SUBSTREAM_FLAG_DATA_EP_STARTED, &subs->flags))
        snd_usb_endpoint_stop(subs->data_endpoint,
                      force, can_sleep, wait);
}

static int deactivate_endpoints(struct snd_usb_substream *subs)
{
    int reta, retb;

    reta = snd_usb_endpoint_deactivate(subs->sync_endpoint);
    retb = snd_usb_endpoint_deactivate(subs->data_endpoint);

    if (reta < 0)
        return reta;

    if (retb < 0)
        return retb;

    return 0;
}

/*
 * find a matching format and set up the interface
 */
static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
{
    struct usb_device *dev = subs->dev;
    struct usb_host_interface *alts;
    struct usb_interface_descriptor *altsd;
    struct usb_interface *iface;
    unsigned int ep, attr;
    int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
    int err, implicit_fb = 0;

    iface = usb_ifnum_to_if(dev, fmt->iface);
    if (WARN_ON(!iface))
        return -EINVAL;
    alts = &iface->altsetting[fmt->altset_idx];
    altsd = get_iface_desc(alts);
    if (WARN_ON(altsd->bAlternateSetting != fmt->altsetting))
        return -EINVAL;

    if (fmt == subs->cur_audiofmt)
        return 0;

    /* close the old interface */
    if (subs->interface >= 0 && subs->interface != fmt->iface) {
        err = usb_set_interface(subs->dev, subs->interface, 0);
        if (err < 0) {
            snd_printk(KERN_ERR "%d:%d:%d: return to setting 0 failed (%d)\n",
                dev->devnum, fmt->iface, fmt->altsetting, err);
            return -EIO;
        }
        subs->interface = -1;
        subs->altset_idx = 0;
    }

    /* set interface */
    if (subs->interface != fmt->iface ||
        subs->altset_idx != fmt->altset_idx) {
        err = usb_set_interface(dev, fmt->iface, fmt->altsetting);
        if (err < 0) {
            snd_printk(KERN_ERR "%d:%d:%d: usb_set_interface failed (%d)\n",
                   dev->devnum, fmt->iface, fmt->altsetting, err);
            return -EIO;
        }
        snd_printdd(KERN_INFO "setting usb interface %d:%d\n",
                fmt->iface, fmt->altsetting);
        subs->interface = fmt->iface;
        subs->altset_idx = fmt->altset_idx;
    }

    subs->data_endpoint = snd_usb_add_endpoint(subs->stream->chip,
                           alts, fmt->endpoint, subs->direction,
                           SND_USB_ENDPOINT_TYPE_DATA);
    if (!subs->data_endpoint)
        return -EINVAL;

    /* we need a sync pipe in async OUT or adaptive IN mode */
    /* check the number of EP, since some devices have broken
     * descriptors which fool us.  if it has only one EP,
     * assume it as adaptive-out or sync-in.
     */
    attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;

    switch (subs->stream->chip->usb_id) {
    case USB_ID(0x0763, 0x2080): /* M-Audio FastTrack Ultra */
    case USB_ID(0x0763, 0x2081):
        if (is_playback) {
            implicit_fb = 1;
            ep = 0x81;
            iface = usb_ifnum_to_if(dev, 2);

            if (!iface || iface->num_altsetting == 0)
                return -EINVAL;

            alts = &iface->altsetting[1];
            goto add_sync_ep;
        }
    }

    if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) ||
         (!is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) &&
        altsd->bNumEndpoints >= 2) {
        /* check sync-pipe endpoint */
        /* ... and check descriptor size before accessing bSynchAddress
           because there is a version of the SB Audigy 2 NX firmware lacking
           the audio fields in the endpoint descriptors */
        if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != 0x01 ||
            (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
             get_endpoint(alts, 1)->bSynchAddress != 0 &&
             !implicit_fb)) {
            snd_printk(KERN_ERR "%d:%d:%d : invalid sync pipe. bmAttributes %02x, bLength %d, bSynchAddress %02x\n",
                   dev->devnum, fmt->iface, fmt->altsetting,
                   get_endpoint(alts, 1)->bmAttributes,
                   get_endpoint(alts, 1)->bLength,
                   get_endpoint(alts, 1)->bSynchAddress);
            return -EINVAL;
        }
        ep = get_endpoint(alts, 1)->bEndpointAddress;
        if (!implicit_fb &&
            get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
            (( is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
             (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
            snd_printk(KERN_ERR "%d:%d:%d : invalid sync pipe. is_playback %d, ep %02x, bSynchAddress %02x\n",
                   dev->devnum, fmt->iface, fmt->altsetting,
                   is_playback, ep, get_endpoint(alts, 0)->bSynchAddress);
            return -EINVAL;
        }

        implicit_fb = (get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_USAGE_MASK)
                == USB_ENDPOINT_USAGE_IMPLICIT_FB;

add_sync_ep:
        subs->sync_endpoint = snd_usb_add_endpoint(subs->stream->chip,
                               alts, ep, !subs->direction,
                               implicit_fb ?
                                SND_USB_ENDPOINT_TYPE_DATA :
                                SND_USB_ENDPOINT_TYPE_SYNC);
        if (!subs->sync_endpoint)
            return -EINVAL;

        subs->data_endpoint->sync_master = subs->sync_endpoint;
    }

    if ((err = snd_usb_init_pitch(subs->stream->chip, fmt->iface, alts, fmt)) < 0)
        return err;

    subs->cur_audiofmt = fmt;

    snd_usb_set_format_quirk(subs, fmt);

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

    return 0;
}

/*
 * configure endpoint params
 *
 * called  during initial setup and upon resume
 */
static int configure_endpoint(struct snd_usb_substream *subs)
{
    int ret;

    /* format changed */
    stop_endpoints(subs, 0, 0, 0);
    ret = snd_usb_endpoint_set_params(subs->data_endpoint,
                      subs->pcm_format,
                      subs->channels,
                      subs->period_bytes,
                      subs->cur_rate,
                      subs->cur_audiofmt,
                      subs->sync_endpoint);
    if (ret < 0)
        return ret;

    if (subs->sync_endpoint)
        ret = snd_usb_endpoint_set_params(subs->sync_endpoint,
                          subs->pcm_format,
                          subs->channels,
                          subs->period_bytes,
                          subs->cur_rate,
                          subs->cur_audiofmt,
                          NULL);
    return ret;
}

/*
 * 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;
    int ret;

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

    subs->pcm_format = params_format(hw_params);
    subs->period_bytes = params_period_bytes(hw_params);
    subs->channels = params_channels(hw_params);
    subs->cur_rate = params_rate(hw_params);

    fmt = find_format(subs);
    if (!fmt) {
        snd_printd(KERN_DEBUG "cannot set format: format = %#x, rate = %d, channels = %d\n",
               subs->pcm_format, subs->cur_rate, subs->channels);
        return -EINVAL;
    }

    down_read(&subs->stream->chip->shutdown_rwsem);
    if (subs->stream->chip->shutdown)
        ret = -ENODEV;
    else
        ret = set_format(subs, fmt);
    up_read(&subs->stream->chip->shutdown_rwsem);
    if (ret < 0)
        return ret;

    subs->interface = fmt->iface;
    subs->altset_idx = fmt->altset_idx;
    subs->need_setup_ep = true;

    return 0;
}

/*
 * 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;
    down_read(&subs->stream->chip->shutdown_rwsem);
    if (!subs->stream->chip->shutdown) {
        stop_endpoints(subs, 0, 1, 1);
        deactivate_endpoints(subs);
    }
    up_read(&subs->stream->chip->shutdown_rwsem);
    return snd_pcm_lib_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;
    struct usb_host_interface *alts;
    struct usb_interface *iface;
    int ret;

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

    down_read(&subs->stream->chip->shutdown_rwsem);
    if (subs->stream->chip->shutdown) {
        ret = -ENODEV;
        goto unlock;
    }
    if (snd_BUG_ON(!subs->data_endpoint)) {
        ret = -EIO;
        goto unlock;
    }

    snd_usb_endpoint_sync_pending_stop(subs->sync_endpoint);
    snd_usb_endpoint_sync_pending_stop(subs->data_endpoint);

    ret = set_format(subs, subs->cur_audiofmt);
    if (ret < 0)
        goto unlock;

    iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
    alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
    ret = snd_usb_init_sample_rate(subs->stream->chip,
                       subs->cur_audiofmt->iface,
                       alts,
                       subs->cur_audiofmt,
                       subs->cur_rate);
    if (ret < 0)
        goto unlock;

    if (subs->need_setup_ep) {
        ret = configure_endpoint(subs);
        if (ret < 0)
            goto unlock;
        subs->need_setup_ep = false;
    }

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

    /* reset the pointer */
    subs->hwptr_done = 0;
    subs->transfer_done = 0;
    subs->last_delay = 0;
    subs->last_frame_number = 0;
    runtime->delay = 0;

    /* 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)
        ret = start_endpoints(subs, 1);

 unlock:
    up_read(&subs->stream->chip->shutdown_rwsem);
    return ret;
}

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,
};

static int hw_check_valid_format(struct snd_usb_substream *subs,
                 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);
    struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
    struct snd_mask check_fmts;
    unsigned int ptime;

    /* check the format */
    snd_mask_none(&check_fmts);
    check_fmts.bits[0] = (u32)fp->formats;
    check_fmts.bits[1] = (u32)(fp->formats >> 32);
    snd_mask_intersect(&check_fmts, fmts);
    if (snd_mask_empty(&check_fmts)) {
        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;
    }
    /* check whether the period time is >= the data packet interval */
    if (subs->speed != USB_SPEED_FULL) {
        ptime = 125 * (1 << fp->datainterval);
        if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
            hwc_debug("   > check: ptime %u > max %u\n", ptime, pt->max);
            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(subs, 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(subs, 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(subs, params, fp))
            continue;
        fbits |= fp->formats;
    }

    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;
}

static int hw_rule_period_time(struct snd_pcm_hw_params *params,
                   struct snd_pcm_hw_rule *rule)
{
    struct snd_usb_substream *subs = rule->private;
    struct audioformat *fp;
    struct snd_interval *it;
    unsigned char min_datainterval;
    unsigned int pmin;
    int changed;

    it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
    hwc_debug("hw_rule_period_time: (%u,%u)\n", it->min, it->max);
    min_datainterval = 0xff;
    list_for_each_entry(fp, &subs->fmt_list, list) {
        if (!hw_check_valid_format(subs, params, fp))
            continue;
        min_datainterval = min(min_datainterval, fp->datainterval);
    }
    if (min_datainterval == 0xff) {
        hwc_debug("  --> get empty\n");
        it->empty = 1;
        return -EINVAL;
    }
    pmin = 125 * (1 << min_datainterval);
    changed = 0;
    if (it->min < pmin) {
        it->min = pmin;
        it->openmin = 0;
        changed = 1;
    }
    if (snd_interval_checkempty(it)) {
        it->empty = 1;
        return -EINVAL;
    }
    hwc_debug("  --> (%u,%u) (changed = %d)\n", it->min, it->max, changed);
    return changed;
}

/*
 *  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 *rate_list;
    int count = 0, needs_knot = 0;
    int err;

    kfree(subs->rate_list.list);
    subs->rate_list.list = NULL;

    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.list = rate_list =
        kmalloc(sizeof(int) * count, GFP_KERNEL);
    if (!subs->rate_list.list)
        return -ENOMEM;
    subs->rate_list.count = count;
    subs->rate_list.mask = 0;
    count = 0;
    list_for_each_entry(fp, &subs->fmt_list, list) {
        int i;
        for (i = 0; i < fp->nr_rates; i++)
            rate_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;
    unsigned int pt, ptmin;
    int param_period_time_if_needed;
    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;
    ptmin = UINT_MAX;
    /* 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 == UAC_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;
        }
        pt = 125 * (1 << fp->datainterval);
        ptmin = min(ptmin, pt);
    }
    err = snd_usb_autoresume(subs->stream->chip);
    if (err < 0)
        return err;

    param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;
    if (subs->speed == USB_SPEED_FULL)
        /* full speed devices have fixed data packet interval */
        ptmin = 1000;
    if (ptmin == 1000)
        /* if period time doesn't go below 1 ms, no rules needed */
        param_period_time_if_needed = -1;
    snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
                     ptmin, UINT_MAX);

    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,
                       param_period_time_if_needed,
                       -1)) < 0)
        goto rep_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,
                       param_period_time_if_needed,
                       -1)) < 0)
        goto rep_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,
                       param_period_time_if_needed,
                       -1)) < 0)
        goto rep_err;
    if (param_period_time_if_needed >= 0) {
        err = snd_pcm_hw_rule_add(runtime, 0,
                      SNDRV_PCM_HW_PARAM_PERIOD_TIME,
                      hw_rule_period_time, subs,
                      SNDRV_PCM_HW_PARAM_FORMAT,
                      SNDRV_PCM_HW_PARAM_CHANNELS,
                      SNDRV_PCM_HW_PARAM_RATE,
                      -1);
        if (err < 0)
            goto rep_err;
    }
    if ((err = snd_usb_pcm_check_knot(runtime, subs)) < 0)
        goto rep_err;
    return 0;

rep_err:
    snd_usb_autosuspend(subs->stream->chip);
    return err;
}

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->altset_idx = 0;
    runtime->hw = snd_usb_hardware;
    runtime->private_data = subs;
    subs->pcm_substream = substream;
    /* runtime PM is also done there */
    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];

    stop_endpoints(subs, 0, 0, 0);

    if (!as->chip->shutdown && subs->interface >= 0) {
        usb_set_interface(subs->dev, subs->interface, 0);
        subs->interface = -1;
    }

    subs->pcm_substream = NULL;
    snd_usb_autosuspend(subs->stream->chip);

    return 0;
}

/* Since a URB can handle only a single linear buffer, we must use double
 * buffering when the data to be transferred overflows the buffer boundary.
 * To avoid inconsistencies when updating hwptr_done, we use double buffering
 * for all URBs.
 */
static void retire_capture_urb(struct snd_usb_substream *subs,
                   struct urb *urb)
{
    struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
    unsigned int stride, frames, bytes, oldptr;
    int i, period_elapsed = 0;
    unsigned long flags;
    unsigned char *cp;

    stride = runtime->frame_bits >> 3;

    for (i = 0; i < urb->number_of_packets; i++) {
        cp = (unsigned char *)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
        if (urb->iso_frame_desc[i].status && printk_ratelimit()) {
            snd_printdd(KERN_ERR "frame %d active: %d\n", i, urb->iso_frame_desc[i].status);
            // continue;
        }
        bytes = urb->iso_frame_desc[i].actual_length;
        frames = bytes / stride;
        if (!subs->txfr_quirk)
            bytes = frames * stride;
        if (bytes % (runtime->sample_bits >> 3) != 0) {
#ifdef CONFIG_SND_DEBUG_VERBOSE
            int oldbytes = bytes;
#endif
            bytes = frames * stride;
            snd_printdd(KERN_ERR "Corrected urb data len. %d->%d\n",
                            oldbytes, bytes);
        }
        /* update the current pointer */
        spin_lock_irqsave(&subs->lock, flags);
        oldptr = subs->hwptr_done;
        subs->hwptr_done += bytes;
        if (subs->hwptr_done >= runtime->buffer_size * stride)
            subs->hwptr_done -= runtime->buffer_size * stride;
        frames = (bytes + (oldptr % stride)) / stride;
        subs->transfer_done += frames;
        if (subs->transfer_done >= runtime->period_size) {
            subs->transfer_done -= runtime->period_size;
            period_elapsed = 1;
        }
        spin_unlock_irqrestore(&subs->lock, flags);
        /* copy a data chunk */
        if (oldptr + bytes > runtime->buffer_size * stride) {
            unsigned int bytes1 =
                    runtime->buffer_size * stride - oldptr;
            memcpy(runtime->dma_area + oldptr, cp, bytes1);
            memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
        } else {
            memcpy(runtime->dma_area + oldptr, cp, bytes);
        }
    }

    if (period_elapsed)
        snd_pcm_period_elapsed(subs->pcm_substream);
}

static void prepare_playback_urb(struct snd_usb_substream *subs,
                 struct urb *urb)
{
    struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
    struct snd_usb_endpoint *ep = subs->data_endpoint;
    struct snd_urb_ctx *ctx = urb->context;
    unsigned int counts, frames, bytes;
    int i, stride, period_elapsed = 0;
    unsigned long flags;

    stride = runtime->frame_bits >> 3;

    frames = 0;
    urb->number_of_packets = 0;
    spin_lock_irqsave(&subs->lock, flags);
    for (i = 0; i < ctx->packets; i++) {
        if (ctx->packet_size[i])
            counts = ctx->packet_size[i];
        else
            counts = snd_usb_endpoint_next_packet_size(ep);

        /* set up descriptor */
        urb->iso_frame_desc[i].offset = frames * stride;
        urb->iso_frame_desc[i].length = counts * stride;
        frames += counts;
        urb->number_of_packets++;
        subs->transfer_done += counts;
        if (subs->transfer_done >= runtime->period_size) {
            subs->transfer_done -= runtime->period_size;
            period_elapsed = 1;
            if (subs->fmt_type == UAC_FORMAT_TYPE_II) {
                if (subs->transfer_done > 0) {
                    /* FIXME: fill-max mode is not
                     * supported yet */
                    frames -= subs->transfer_done;
                    counts -= subs->transfer_done;
                    urb->iso_frame_desc[i].length =
                        counts * stride;
                    subs->transfer_done = 0;
                }
                i++;
                if (i < ctx->packets) {
                    /* add a transfer delimiter */
                    urb->iso_frame_desc[i].offset =
                        frames * stride;
                    urb->iso_frame_desc[i].length = 0;
                    urb->number_of_packets++;
                }
                break;
            }
        }
        if (period_elapsed &&
            !snd_usb_endpoint_implict_feedback_sink(subs->data_endpoint)) /* finish at the period boundary */
            break;
    }
    bytes = frames * stride;
    if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
        /* err, the transferred area goes over buffer boundary. */
        unsigned int bytes1 =
            runtime->buffer_size * stride - subs->hwptr_done;
        memcpy(urb->transfer_buffer,
               runtime->dma_area + subs->hwptr_done, bytes1);
        memcpy(urb->transfer_buffer + bytes1,
               runtime->dma_area, bytes - bytes1);
    } else {
        memcpy(urb->transfer_buffer,
               runtime->dma_area + subs->hwptr_done, bytes);
    }
    subs->hwptr_done += bytes;
    if (subs->hwptr_done >= runtime->buffer_size * stride)
        subs->hwptr_done -= runtime->buffer_size * stride;

    /* update delay with exact number of samples queued */
    runtime->delay = subs->last_delay;
    runtime->delay += frames;
    subs->last_delay = runtime->delay;

    /* realign last_frame_number */
    subs->last_frame_number = usb_get_current_frame_number(subs->dev);
    subs->last_frame_number &= 0xFF; /* keep 8 LSBs */

    spin_unlock_irqrestore(&subs->lock, flags);
    urb->transfer_buffer_length = bytes;
    if (period_elapsed)
        snd_pcm_period_elapsed(subs->pcm_substream);
}

/*
 * process after playback data complete
 * - decrease the delay count again
 */
static void retire_playback_urb(struct snd_usb_substream *subs,
                   struct urb *urb)
{
    unsigned long flags;
    struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
    int stride = runtime->frame_bits >> 3;
    int processed = urb->transfer_buffer_length / stride;
    int est_delay;

    /* ignore the delay accounting when procssed=0 is given, i.e.
     * silent payloads are procssed before handling the actual data
     */
    if (!processed)
        return;

    spin_lock_irqsave(&subs->lock, flags);
    est_delay = snd_usb_pcm_delay(subs, runtime->rate);
    /* update delay with exact number of samples played */
    if (processed > subs->last_delay)
        subs->last_delay = 0;
    else
        subs->last_delay -= processed;
    runtime->delay = subs->last_delay;

    /*
     * Report when delay estimate is off by more than 2ms.
     * The error should be lower than 2ms since the estimate relies
     * on two reads of a counter updated every ms.
     */
    if (abs(est_delay - subs->last_delay) * 1000 > runtime->rate * 2)
        snd_printk(KERN_DEBUG "delay: estimated %d, actual %d\n",
            est_delay, subs->last_delay);

    spin_unlock_irqrestore(&subs->lock, flags);
}

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 int snd_usb_substream_playback_trigger(struct snd_pcm_substream *substream,
                          int cmd)
{
    struct snd_usb_substream *subs = substream->runtime->private_data;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        subs->data_endpoint->prepare_data_urb = prepare_playback_urb;
        subs->data_endpoint->retire_data_urb = retire_playback_urb;
        subs->running = 1;
        return 0;
    case SNDRV_PCM_TRIGGER_STOP:
        stop_endpoints(subs, 0, 0, 0);
        subs->running = 0;
        return 0;
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        subs->data_endpoint->prepare_data_urb = NULL;
        subs->data_endpoint->retire_data_urb = NULL;
        subs->running = 0;
        return 0;
    }

    return -EINVAL;
}

static int snd_usb_substream_capture_trigger(struct snd_pcm_substream *substream,
                         int cmd)
{
    int err;
    struct snd_usb_substream *subs = substream->runtime->private_data;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        err = start_endpoints(subs, 0);
        if (err < 0)
            return err;

        subs->data_endpoint->retire_data_urb = retire_capture_urb;
        subs->running = 1;
        return 0;
    case SNDRV_PCM_TRIGGER_STOP:
        stop_endpoints(subs, 0, 0, 0);
        subs->running = 0;
        return 0;
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        subs->data_endpoint->retire_data_urb = NULL;
        subs->running = 0;
        return 0;
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        subs->data_endpoint->retire_data_urb = retire_capture_urb;
        subs->running = 1;
        return 0;
    }

    return -EINVAL;
}

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_substream_playback_trigger,
    .pointer =  snd_usb_pcm_pointer,
    .page =     snd_pcm_lib_get_vmalloc_page,
    .mmap =     snd_pcm_lib_mmap_vmalloc,
};

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_substream_capture_trigger,
    .pointer =  snd_usb_pcm_pointer,
    .page =     snd_pcm_lib_get_vmalloc_page,
    .mmap =     snd_pcm_lib_mmap_vmalloc,
};

void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
{
    snd_pcm_set_ops(pcm, stream,
            stream == SNDRV_PCM_STREAM_PLAYBACK ?
            &snd_usb_playback_ops : &snd_usb_capture_ops);
}