usbusx2yaudio.c

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/*
 *   US-X2Y AUDIO
 *   Copyright (c) 2002-2004 by Karsten Wiese
 *
 *   based on
 *
 *   (Tentative) USB Audio Driver for ALSA
 *
 *   Main and PCM part
 *
 *   Copyright (c) 2002 by Takashi Iwai <[email protected]>
 *
 *   Many codes borrowed from audio.c by 
 *      Alan Cox ([email protected])
 *      Thomas Sailer ([email protected])
 *
 *
 *   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/interrupt.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/moduleparam.h>
#include <sound/core.h>
#include <sound/info.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include "usx2y.h"
#include "usbusx2y.h"

#define USX2Y_NRPACKS 4         /* Default value used for nr of packs per urb.
                      1 to 4 have been tested ok on uhci.
                      To use 3 on ohci, you'd need a patch:
                      look for "0000425-linux-2.6.9-rc4-mm1_ohci-hcd.patch.gz" on
                      "https://bugtrack.alsa-project.org/alsa-bug/bug_view_page.php?bug_id=0000425"
                      .
                      1, 2 and 4 work out of the box on ohci, if I recall correctly.
                      Bigger is safer operation,
                      smaller gives lower latencies.
                    */
#define USX2Y_NRPACKS_VARIABLE y    /* If your system works ok with this module's parameter
                       nrpacks set to 1, you might as well comment 
                       this #define out, and thereby produce smaller, faster code.
                       You'd also set USX2Y_NRPACKS to 1 then.
                    */

#ifdef USX2Y_NRPACKS_VARIABLE
 static int nrpacks = USX2Y_NRPACKS; /* number of packets per urb */
 #define  nr_of_packs() nrpacks
 module_param(nrpacks, int, 0444);
 MODULE_PARM_DESC(nrpacks, "Number of packets per URB.");
#else
 #define nr_of_packs() USX2Y_NRPACKS
#endif


static int usX2Y_urb_capt_retire(struct snd_usX2Y_substream *subs)
{
    struct urb  *urb = subs->completed_urb;
    struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
    unsigned char   *cp;
    int         i, len, lens = 0, hwptr_done = subs->hwptr_done;
    struct usX2Ydev *usX2Y = subs->usX2Y;

    for (i = 0; i < nr_of_packs(); i++) {
        cp = (unsigned char*)urb->transfer_buffer + urb->iso_frame_desc[i].offset;
        if (urb->iso_frame_desc[i].status) { /* active? hmm, skip this */
            snd_printk(KERN_ERR "active frame status %i. "
                   "Most probably some hardware problem.\n",
                   urb->iso_frame_desc[i].status);
            return urb->iso_frame_desc[i].status;
        }
        len = urb->iso_frame_desc[i].actual_length / usX2Y->stride;
        if (! len) {
            snd_printd("0 == len ERROR!\n");
            continue;
        }

        /* copy a data chunk */
        if ((hwptr_done + len) > runtime->buffer_size) {
            int cnt = runtime->buffer_size - hwptr_done;
            int blen = cnt * usX2Y->stride;
            memcpy(runtime->dma_area + hwptr_done * usX2Y->stride, cp, blen);
            memcpy(runtime->dma_area, cp + blen, len * usX2Y->stride - blen);
        } else {
            memcpy(runtime->dma_area + hwptr_done * usX2Y->stride, cp,
                   len * usX2Y->stride);
        }
        lens += len;
        if ((hwptr_done += len) >= runtime->buffer_size)
            hwptr_done -= runtime->buffer_size;
    }

    subs->hwptr_done = hwptr_done;
    subs->transfer_done += lens;
    /* update the pointer, call callback if necessary */
    if (subs->transfer_done >= runtime->period_size) {
        subs->transfer_done -= runtime->period_size;
        snd_pcm_period_elapsed(subs->pcm_substream);
    }
    return 0;
}
/*
 * prepare urb for playback data pipe
 *
 * we copy the data directly from the pcm buffer.
 * the current position to be copied is held in hwptr field.
 * since a urb can handle only a single linear buffer, if the total
 * transferred area overflows the buffer boundary, we cannot send
 * it directly from the buffer.  thus the data is once copied to
 * a temporary buffer and urb points to that.
 */
static int usX2Y_urb_play_prepare(struct snd_usX2Y_substream *subs,
                  struct urb *cap_urb,
                  struct urb *urb)
{
    int count, counts, pack;
    struct usX2Ydev *usX2Y = subs->usX2Y;
    struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;

    count = 0;
    for (pack = 0; pack <  nr_of_packs(); pack++) {
        /* calculate the size of a packet */
        counts = cap_urb->iso_frame_desc[pack].actual_length / usX2Y->stride;
        count += counts;
        if (counts < 43 || counts > 50) {
            snd_printk(KERN_ERR "should not be here with counts=%i\n", counts);
            return -EPIPE;
        }
        /* set up descriptor */
        urb->iso_frame_desc[pack].offset = pack ?
            urb->iso_frame_desc[pack - 1].offset +
            urb->iso_frame_desc[pack - 1].length :
            0;
        urb->iso_frame_desc[pack].length = cap_urb->iso_frame_desc[pack].actual_length;
    }
    if (atomic_read(&subs->state) >= state_PRERUNNING)
        if (subs->hwptr + count > runtime->buffer_size) {
            /* err, the transferred area goes over buffer boundary.
             * copy the data to the temp buffer.
             */
            int len;
            len = runtime->buffer_size - subs->hwptr;
            urb->transfer_buffer = subs->tmpbuf;
            memcpy(subs->tmpbuf, runtime->dma_area +
                   subs->hwptr * usX2Y->stride, len * usX2Y->stride);
            memcpy(subs->tmpbuf + len * usX2Y->stride,
                   runtime->dma_area, (count - len) * usX2Y->stride);
            subs->hwptr += count;
            subs->hwptr -= runtime->buffer_size;
        } else {
            /* set the buffer pointer */
            urb->transfer_buffer = runtime->dma_area + subs->hwptr * usX2Y->stride;
            if ((subs->hwptr += count) >= runtime->buffer_size)
            subs->hwptr -= runtime->buffer_size;            
        }
    else
        urb->transfer_buffer = subs->tmpbuf;
    urb->transfer_buffer_length = count * usX2Y->stride;
    return 0;
}

/*
 * process after playback data complete
 *
 * update the current position and call callback if a period is processed.
 */
static void usX2Y_urb_play_retire(struct snd_usX2Y_substream *subs, struct urb *urb)
{
    struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
    int     len = urb->actual_length / subs->usX2Y->stride;

    subs->transfer_done += len;
    subs->hwptr_done +=  len;
    if (subs->hwptr_done >= runtime->buffer_size)
        subs->hwptr_done -= runtime->buffer_size;
    if (subs->transfer_done >= runtime->period_size) {
        subs->transfer_done -= runtime->period_size;
        snd_pcm_period_elapsed(subs->pcm_substream);
    }
}

static int usX2Y_urb_submit(struct snd_usX2Y_substream *subs, struct urb *urb, int frame)
{
    int err;
    if (!urb)
        return -ENODEV;
    urb->start_frame = (frame + NRURBS * nr_of_packs());  // let hcd do rollover sanity checks
    urb->hcpriv = NULL;
    urb->dev = subs->usX2Y->dev; /* we need to set this at each time */
    if ((err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
        snd_printk(KERN_ERR "usb_submit_urb() returned %i\n", err);
        return err;
    }
    return 0;
}

static inline int usX2Y_usbframe_complete(struct snd_usX2Y_substream *capsubs,
                      struct snd_usX2Y_substream *playbacksubs,
                      int frame)
{
    int err, state;
    struct urb *urb = playbacksubs->completed_urb;

    state = atomic_read(&playbacksubs->state);
    if (NULL != urb) {
        if (state == state_RUNNING)
            usX2Y_urb_play_retire(playbacksubs, urb);
        else if (state >= state_PRERUNNING)
            atomic_inc(&playbacksubs->state);
    } else {
        switch (state) {
        case state_STARTING1:
            urb = playbacksubs->urb[0];
            atomic_inc(&playbacksubs->state);
            break;
        case state_STARTING2:
            urb = playbacksubs->urb[1];
            atomic_inc(&playbacksubs->state);
            break;
        }
    }
    if (urb) {
        if ((err = usX2Y_urb_play_prepare(playbacksubs, capsubs->completed_urb, urb)) ||
            (err = usX2Y_urb_submit(playbacksubs, urb, frame))) {
            return err;
        }
    }

    playbacksubs->completed_urb = NULL;

    state = atomic_read(&capsubs->state);
    if (state >= state_PREPARED) {
        if (state == state_RUNNING) {
            if ((err = usX2Y_urb_capt_retire(capsubs)))
                return err;
        } else if (state >= state_PRERUNNING)
            atomic_inc(&capsubs->state);
        if ((err = usX2Y_urb_submit(capsubs, capsubs->completed_urb, frame)))
            return err;
    }
    capsubs->completed_urb = NULL;
    return 0;
}


static void usX2Y_clients_stop(struct usX2Ydev *usX2Y)
{
    int s, u;

    for (s = 0; s < 4; s++) {
        struct snd_usX2Y_substream *subs = usX2Y->subs[s];
        if (subs) {
            snd_printdd("%i %p state=%i\n", s, subs, atomic_read(&subs->state));
            atomic_set(&subs->state, state_STOPPED);
        }
    }
    for (s = 0; s < 4; s++) {
        struct snd_usX2Y_substream *subs = usX2Y->subs[s];
        if (subs) {
            if (atomic_read(&subs->state) >= state_PRERUNNING) {
                snd_pcm_stop(subs->pcm_substream, SNDRV_PCM_STATE_XRUN);
            }
            for (u = 0; u < NRURBS; u++) {
                struct urb *urb = subs->urb[u];
                if (NULL != urb)
                    snd_printdd("%i status=%i start_frame=%i\n",
                            u, urb->status, urb->start_frame);
            }
        }
    }
    usX2Y->prepare_subs = NULL;
    wake_up(&usX2Y->prepare_wait_queue);
}

static void usX2Y_error_urb_status(struct usX2Ydev *usX2Y,
                   struct snd_usX2Y_substream *subs, struct urb *urb)
{
    snd_printk(KERN_ERR "ep=%i stalled with status=%i\n", subs->endpoint, urb->status);
    urb->status = 0;
    usX2Y_clients_stop(usX2Y);
}

static void usX2Y_error_sequence(struct usX2Ydev *usX2Y,
                 struct snd_usX2Y_substream *subs, struct urb *urb)
{
    snd_printk(KERN_ERR
"Sequence Error!(hcd_frame=%i ep=%i%s;wait=%i,frame=%i).\n"
"Most probably some urb of usb-frame %i is still missing.\n"
"Cause could be too long delays in usb-hcd interrupt handling.\n",
           usb_get_current_frame_number(usX2Y->dev),
           subs->endpoint, usb_pipein(urb->pipe) ? "in" : "out",
           usX2Y->wait_iso_frame, urb->start_frame, usX2Y->wait_iso_frame);
    usX2Y_clients_stop(usX2Y);
}

static void i_usX2Y_urb_complete(struct urb *urb)
{
    struct snd_usX2Y_substream *subs = urb->context;
    struct usX2Ydev *usX2Y = subs->usX2Y;

    if (unlikely(atomic_read(&subs->state) < state_PREPARED)) {
        snd_printdd("hcd_frame=%i ep=%i%s status=%i start_frame=%i\n",
                usb_get_current_frame_number(usX2Y->dev),
                subs->endpoint, usb_pipein(urb->pipe) ? "in" : "out",
                urb->status, urb->start_frame);
        return;
    }
    if (unlikely(urb->status)) {
        usX2Y_error_urb_status(usX2Y, subs, urb);
        return;
    }
    if (likely((urb->start_frame & 0xFFFF) == (usX2Y->wait_iso_frame & 0xFFFF)))
        subs->completed_urb = urb;
    else {
        usX2Y_error_sequence(usX2Y, subs, urb);
        return;
    }
    {
        struct snd_usX2Y_substream *capsubs = usX2Y->subs[SNDRV_PCM_STREAM_CAPTURE],
            *playbacksubs = usX2Y->subs[SNDRV_PCM_STREAM_PLAYBACK];
        if (capsubs->completed_urb &&
            atomic_read(&capsubs->state) >= state_PREPARED &&
            (playbacksubs->completed_urb ||
             atomic_read(&playbacksubs->state) < state_PREPARED)) {
            if (!usX2Y_usbframe_complete(capsubs, playbacksubs, urb->start_frame))
                usX2Y->wait_iso_frame += nr_of_packs();
            else {
                snd_printdd("\n");
                usX2Y_clients_stop(usX2Y);
            }
        }
    }
}

static void usX2Y_urbs_set_complete(struct usX2Ydev * usX2Y,
                    void (*complete)(struct urb *))
{
    int s, u;
    for (s = 0; s < 4; s++) {
        struct snd_usX2Y_substream *subs = usX2Y->subs[s];
        if (NULL != subs)
            for (u = 0; u < NRURBS; u++) {
                struct urb * urb = subs->urb[u];
                if (NULL != urb)
                    urb->complete = complete;
            }
    }
}

static void usX2Y_subs_startup_finish(struct usX2Ydev * usX2Y)
{
    usX2Y_urbs_set_complete(usX2Y, i_usX2Y_urb_complete);
    usX2Y->prepare_subs = NULL;
}

static void i_usX2Y_subs_startup(struct urb *urb)
{
    struct snd_usX2Y_substream *subs = urb->context;
    struct usX2Ydev *usX2Y = subs->usX2Y;
    struct snd_usX2Y_substream *prepare_subs = usX2Y->prepare_subs;
    if (NULL != prepare_subs)
        if (urb->start_frame == prepare_subs->urb[0]->start_frame) {
            usX2Y_subs_startup_finish(usX2Y);
            atomic_inc(&prepare_subs->state);
            wake_up(&usX2Y->prepare_wait_queue);
        }

    i_usX2Y_urb_complete(urb);
}

static void usX2Y_subs_prepare(struct snd_usX2Y_substream *subs)
{
    snd_printdd("usX2Y_substream_prepare(%p) ep=%i urb0=%p urb1=%p\n",
            subs, subs->endpoint, subs->urb[0], subs->urb[1]);
    /* reset the pointer */
    subs->hwptr = 0;
    subs->hwptr_done = 0;
    subs->transfer_done = 0;
}


static void usX2Y_urb_release(struct urb **urb, int free_tb)
{
    if (*urb) {
        usb_kill_urb(*urb);
        if (free_tb)
            kfree((*urb)->transfer_buffer);
        usb_free_urb(*urb);
        *urb = NULL;
    }
}
/*
 * release a substreams urbs
 */
static void usX2Y_urbs_release(struct snd_usX2Y_substream *subs)
{
    int i;
    snd_printdd("usX2Y_urbs_release() %i\n", subs->endpoint);
    for (i = 0; i < NRURBS; i++)
        usX2Y_urb_release(subs->urb + i,
                  subs != subs->usX2Y->subs[SNDRV_PCM_STREAM_PLAYBACK]);

    kfree(subs->tmpbuf);
    subs->tmpbuf = NULL;
}
/*
 * initialize a substream's urbs
 */
static int usX2Y_urbs_allocate(struct snd_usX2Y_substream *subs)
{
    int i;
    unsigned int pipe;
    int is_playback = subs == subs->usX2Y->subs[SNDRV_PCM_STREAM_PLAYBACK];
    struct usb_device *dev = subs->usX2Y->dev;

    pipe = is_playback ? usb_sndisocpipe(dev, subs->endpoint) :
            usb_rcvisocpipe(dev, subs->endpoint);
    subs->maxpacksize = usb_maxpacket(dev, pipe, is_playback);
    if (!subs->maxpacksize)
        return -EINVAL;

    if (is_playback && NULL == subs->tmpbuf) {  /* allocate a temporary buffer for playback */
        subs->tmpbuf = kcalloc(nr_of_packs(), subs->maxpacksize, GFP_KERNEL);
        if (NULL == subs->tmpbuf) {
            snd_printk(KERN_ERR "cannot malloc tmpbuf\n");
            return -ENOMEM;
        }
    }
    /* allocate and initialize data urbs */
    for (i = 0; i < NRURBS; i++) {
        struct urb **purb = subs->urb + i;
        if (*purb) {
            usb_kill_urb(*purb);
            continue;
        }
        *purb = usb_alloc_urb(nr_of_packs(), GFP_KERNEL);
        if (NULL == *purb) {
            usX2Y_urbs_release(subs);
            return -ENOMEM;
        }
        if (!is_playback && !(*purb)->transfer_buffer) {
            /* allocate a capture buffer per urb */
            (*purb)->transfer_buffer = kmalloc(subs->maxpacksize * nr_of_packs(), GFP_KERNEL);
            if (NULL == (*purb)->transfer_buffer) {
                usX2Y_urbs_release(subs);
                return -ENOMEM;
            }
        }
        (*purb)->dev = dev;
        (*purb)->pipe = pipe;
        (*purb)->number_of_packets = nr_of_packs();
        (*purb)->context = subs;
        (*purb)->interval = 1;
        (*purb)->complete = i_usX2Y_subs_startup;
    }
    return 0;
}

static void usX2Y_subs_startup(struct snd_usX2Y_substream *subs)
{
    struct usX2Ydev *usX2Y = subs->usX2Y;
    usX2Y->prepare_subs = subs;
    subs->urb[0]->start_frame = -1;
    wmb();
    usX2Y_urbs_set_complete(usX2Y, i_usX2Y_subs_startup);
}

static int usX2Y_urbs_start(struct snd_usX2Y_substream *subs)
{
    int i, err;
    struct usX2Ydev *usX2Y = subs->usX2Y;

    if ((err = usX2Y_urbs_allocate(subs)) < 0)
        return err;
    subs->completed_urb = NULL;
    for (i = 0; i < 4; i++) {
        struct snd_usX2Y_substream *subs = usX2Y->subs[i];
        if (subs != NULL && atomic_read(&subs->state) >= state_PREPARED)
            goto start;
    }

 start:
    usX2Y_subs_startup(subs);
    for (i = 0; i < NRURBS; i++) {
        struct urb *urb = subs->urb[i];
        if (usb_pipein(urb->pipe)) {
            unsigned long pack;
            if (0 == i)
                atomic_set(&subs->state, state_STARTING3);
            urb->dev = usX2Y->dev;
            urb->transfer_flags = URB_ISO_ASAP;
            for (pack = 0; pack < nr_of_packs(); pack++) {
                urb->iso_frame_desc[pack].offset = subs->maxpacksize * pack;
                urb->iso_frame_desc[pack].length = subs->maxpacksize;
            }
            urb->transfer_buffer_length = subs->maxpacksize * nr_of_packs(); 
            if ((err = usb_submit_urb(urb, GFP_ATOMIC)) < 0) {
                snd_printk (KERN_ERR "cannot submit datapipe for urb %d, err = %d\n", i, err);
                err = -EPIPE;
                goto cleanup;
            } else
                if (i == 0)
                    usX2Y->wait_iso_frame = urb->start_frame;
            urb->transfer_flags = 0;
        } else {
            atomic_set(&subs->state, state_STARTING1);
            break;
        }
    }
    err = 0;
    wait_event(usX2Y->prepare_wait_queue, NULL == usX2Y->prepare_subs);
    if (atomic_read(&subs->state) != state_PREPARED)
        err = -EPIPE;

 cleanup:
    if (err) {
        usX2Y_subs_startup_finish(usX2Y);
        usX2Y_clients_stop(usX2Y);      // something is completely wroong > stop evrything
    }
    return err;
}

/*
 * return the current pcm pointer.  just return the hwptr_done value.
 */
static snd_pcm_uframes_t snd_usX2Y_pcm_pointer(struct snd_pcm_substream *substream)
{
    struct snd_usX2Y_substream *subs = substream->runtime->private_data;
    return subs->hwptr_done;
}
/*
 * start/stop substream
 */
static int snd_usX2Y_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct snd_usX2Y_substream *subs = substream->runtime->private_data;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        snd_printdd("snd_usX2Y_pcm_trigger(START)\n");
        if (atomic_read(&subs->state) == state_PREPARED &&
            atomic_read(&subs->usX2Y->subs[SNDRV_PCM_STREAM_CAPTURE]->state) >= state_PREPARED) {
            atomic_set(&subs->state, state_PRERUNNING);
        } else {
            snd_printdd("\n");
            return -EPIPE;
        }
        break;
    case SNDRV_PCM_TRIGGER_STOP:
        snd_printdd("snd_usX2Y_pcm_trigger(STOP)\n");
        if (atomic_read(&subs->state) >= state_PRERUNNING)
            atomic_set(&subs->state, state_PREPARED);
        break;
    default:
        return -EINVAL;
    }
    return 0;
}


/*
 * allocate a buffer, setup samplerate
 *
 * 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 struct s_c2
{
    char c1, c2;
}
    SetRate44100[] =
{
    { 0x14, 0x08},  // this line sets 44100, well actually a little less
    { 0x18, 0x40},  // only tascam / frontier design knows the further lines .......
    { 0x18, 0x42},
    { 0x18, 0x45},
    { 0x18, 0x46},
    { 0x18, 0x48},
    { 0x18, 0x4A},
    { 0x18, 0x4C},
    { 0x18, 0x4E},
    { 0x18, 0x50},
    { 0x18, 0x52},
    { 0x18, 0x54},
    { 0x18, 0x56},
    { 0x18, 0x58},
    { 0x18, 0x5A},
    { 0x18, 0x5C},
    { 0x18, 0x5E},
    { 0x18, 0x60},
    { 0x18, 0x62},
    { 0x18, 0x64},
    { 0x18, 0x66},
    { 0x18, 0x68},
    { 0x18, 0x6A},
    { 0x18, 0x6C},
    { 0x18, 0x6E},
    { 0x18, 0x70},
    { 0x18, 0x72},
    { 0x18, 0x74},
    { 0x18, 0x76},
    { 0x18, 0x78},
    { 0x18, 0x7A},
    { 0x18, 0x7C},
    { 0x18, 0x7E}
};
static struct s_c2 SetRate48000[] =
{
    { 0x14, 0x09},  // this line sets 48000, well actually a little less
    { 0x18, 0x40},  // only tascam / frontier design knows the further lines .......
    { 0x18, 0x42},
    { 0x18, 0x45},
    { 0x18, 0x46},
    { 0x18, 0x48},
    { 0x18, 0x4A},
    { 0x18, 0x4C},
    { 0x18, 0x4E},
    { 0x18, 0x50},
    { 0x18, 0x52},
    { 0x18, 0x54},
    { 0x18, 0x56},
    { 0x18, 0x58},
    { 0x18, 0x5A},
    { 0x18, 0x5C},
    { 0x18, 0x5E},
    { 0x18, 0x60},
    { 0x18, 0x62},
    { 0x18, 0x64},
    { 0x18, 0x66},
    { 0x18, 0x68},
    { 0x18, 0x6A},
    { 0x18, 0x6C},
    { 0x18, 0x6E},
    { 0x18, 0x70},
    { 0x18, 0x73},
    { 0x18, 0x74},
    { 0x18, 0x76},
    { 0x18, 0x78},
    { 0x18, 0x7A},
    { 0x18, 0x7C},
    { 0x18, 0x7E}
};
#define NOOF_SETRATE_URBS ARRAY_SIZE(SetRate48000)

static void i_usX2Y_04Int(struct urb *urb)
{
    struct usX2Ydev *usX2Y = urb->context;
    
    if (urb->status)
        snd_printk(KERN_ERR "snd_usX2Y_04Int() urb->status=%i\n", urb->status);
    if (0 == --usX2Y->US04->len)
        wake_up(&usX2Y->In04WaitQueue);
}

static int usX2Y_rate_set(struct usX2Ydev *usX2Y, int rate)
{
    int         err = 0, i;
    struct snd_usX2Y_urbSeq *us = NULL;
    int         *usbdata = NULL;
    struct s_c2     *ra = rate == 48000 ? SetRate48000 : SetRate44100;

    if (usX2Y->rate != rate) {
        us = kzalloc(sizeof(*us) + sizeof(struct urb*) * NOOF_SETRATE_URBS, GFP_KERNEL);
        if (NULL == us) {
            err = -ENOMEM;
            goto cleanup;
        }
        usbdata = kmalloc(sizeof(int) * NOOF_SETRATE_URBS, GFP_KERNEL);
        if (NULL == usbdata) {
            err = -ENOMEM;
            goto cleanup;
        }
        for (i = 0; i < NOOF_SETRATE_URBS; ++i) {
            if (NULL == (us->urb[i] = usb_alloc_urb(0, GFP_KERNEL))) {
                err = -ENOMEM;
                goto cleanup;
            }
            ((char*)(usbdata + i))[0] = ra[i].c1;
            ((char*)(usbdata + i))[1] = ra[i].c2;
            usb_fill_bulk_urb(us->urb[i], usX2Y->dev, usb_sndbulkpipe(usX2Y->dev, 4),
                      usbdata + i, 2, i_usX2Y_04Int, usX2Y);
#ifdef OLD_USB
            us->urb[i]->transfer_flags = USB_QUEUE_BULK;
#endif
        }
        us->submitted = 0;
        us->len =   NOOF_SETRATE_URBS;
        usX2Y->US04 =   us;
        wait_event_timeout(usX2Y->In04WaitQueue, 0 == us->len, HZ);
        usX2Y->US04 =   NULL;
        if (us->len)
            err = -ENODEV;
    cleanup:
        if (us) {
            us->submitted = 2*NOOF_SETRATE_URBS;
            for (i = 0; i < NOOF_SETRATE_URBS; ++i) {
                struct urb *urb = us->urb[i];
                if (urb->status) {
                    if (!err)
                        err = -ENODEV;
                    usb_kill_urb(urb);
                }
                usb_free_urb(urb);
            }
            usX2Y->US04 = NULL;
            kfree(usbdata);
            kfree(us);
            if (!err)
                usX2Y->rate = rate;
        }
    }

    return err;
}


static int usX2Y_format_set(struct usX2Ydev *usX2Y, snd_pcm_format_t format)
{
    int alternate, err;
    struct list_head* p;
    if (format == SNDRV_PCM_FORMAT_S24_3LE) {
        alternate = 2;
        usX2Y->stride = 6;
    } else {
        alternate = 1;
        usX2Y->stride = 4;
    }
    list_for_each(p, &usX2Y->midi_list) {
        snd_usbmidi_input_stop(p);
    }
    usb_kill_urb(usX2Y->In04urb);
    if ((err = usb_set_interface(usX2Y->dev, 0, alternate))) {
        snd_printk(KERN_ERR "usb_set_interface error \n");
        return err;
    }
    usX2Y->In04urb->dev = usX2Y->dev;
    err = usb_submit_urb(usX2Y->In04urb, GFP_KERNEL);
    list_for_each(p, &usX2Y->midi_list) {
        snd_usbmidi_input_start(p);
    }
    usX2Y->format = format;
    usX2Y->rate = 0;
    return err;
}


static int snd_usX2Y_pcm_hw_params(struct snd_pcm_substream *substream,
                   struct snd_pcm_hw_params *hw_params)
{
    int         err = 0;
    unsigned int        rate = params_rate(hw_params);
    snd_pcm_format_t    format = params_format(hw_params);
    struct snd_card *card = substream->pstr->pcm->card;
    struct list_head *list;

    snd_printdd("snd_usX2Y_hw_params(%p, %p)\n", substream, hw_params);
    // all pcm substreams off one usX2Y have to operate at the same rate & format
    list_for_each(list, &card->devices) {
        struct snd_device *dev;
        struct snd_pcm *pcm;
        int s;
        dev = snd_device(list);
        if (dev->type != SNDRV_DEV_PCM)
            continue;
        pcm = dev->device_data;
        for (s = 0; s < 2; ++s) {
            struct snd_pcm_substream *test_substream;
            test_substream = pcm->streams[s].substream;
            if (test_substream && test_substream != substream  &&
                test_substream->runtime &&
                ((test_substream->runtime->format &&
                  test_substream->runtime->format != format) ||
                 (test_substream->runtime->rate &&
                  test_substream->runtime->rate != rate)))
                return -EINVAL;
        }
    }
    if (0 > (err = snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(hw_params)))) {
        snd_printk(KERN_ERR "snd_pcm_lib_malloc_pages(%p, %i) returned %i\n",
               substream, params_buffer_bytes(hw_params), err);
        return err;
    }
    return 0;
}

/*
 * free the buffer
 */
static int snd_usX2Y_pcm_hw_free(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct snd_usX2Y_substream *subs = runtime->private_data;
    mutex_lock(&subs->usX2Y->prepare_mutex);
    snd_printdd("snd_usX2Y_hw_free(%p)\n", substream);

    if (SNDRV_PCM_STREAM_PLAYBACK == substream->stream) {
        struct snd_usX2Y_substream *cap_subs = subs->usX2Y->subs[SNDRV_PCM_STREAM_CAPTURE];
        atomic_set(&subs->state, state_STOPPED);
        usX2Y_urbs_release(subs);
        if (!cap_subs->pcm_substream ||
            !cap_subs->pcm_substream->runtime ||
            !cap_subs->pcm_substream->runtime->status ||
            cap_subs->pcm_substream->runtime->status->state < SNDRV_PCM_STATE_PREPARED) {
            atomic_set(&cap_subs->state, state_STOPPED);
            usX2Y_urbs_release(cap_subs);
        }
    } else {
        struct snd_usX2Y_substream *playback_subs = subs->usX2Y->subs[SNDRV_PCM_STREAM_PLAYBACK];
        if (atomic_read(&playback_subs->state) < state_PREPARED) {
            atomic_set(&subs->state, state_STOPPED);
            usX2Y_urbs_release(subs);
        }
    }
    mutex_unlock(&subs->usX2Y->prepare_mutex);
    return snd_pcm_lib_free_pages(substream);
}
/*
 * prepare callback
 *
 * set format and initialize urbs
 */
static int snd_usX2Y_pcm_prepare(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct snd_usX2Y_substream *subs = runtime->private_data;
    struct usX2Ydev *usX2Y = subs->usX2Y;
    struct snd_usX2Y_substream *capsubs = subs->usX2Y->subs[SNDRV_PCM_STREAM_CAPTURE];
    int err = 0;
    snd_printdd("snd_usX2Y_pcm_prepare(%p)\n", substream);

    mutex_lock(&usX2Y->prepare_mutex);
    usX2Y_subs_prepare(subs);
// Start hardware streams
// SyncStream first....
    if (atomic_read(&capsubs->state) < state_PREPARED) {
        if (usX2Y->format != runtime->format)
            if ((err = usX2Y_format_set(usX2Y, runtime->format)) < 0)
                goto up_prepare_mutex;
        if (usX2Y->rate != runtime->rate)
            if ((err = usX2Y_rate_set(usX2Y, runtime->rate)) < 0)
                goto up_prepare_mutex;
        snd_printdd("starting capture pipe for %s\n", subs == capsubs ? "self" : "playpipe");
        if (0 > (err = usX2Y_urbs_start(capsubs)))
            goto up_prepare_mutex;
    }

    if (subs != capsubs && atomic_read(&subs->state) < state_PREPARED)
        err = usX2Y_urbs_start(subs);

 up_prepare_mutex:
    mutex_unlock(&usX2Y->prepare_mutex);
    return err;
}

static struct snd_pcm_hardware snd_usX2Y_2c =
{
    .info =         (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
                 SNDRV_PCM_INFO_MMAP_VALID |
                 SNDRV_PCM_INFO_BATCH),
    .formats =                 SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_3LE,
    .rates =                   SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000,
    .rate_min =                44100,
    .rate_max =                48000,
    .channels_min =            2,
    .channels_max =            2,
    .buffer_bytes_max = (2*128*1024),
    .period_bytes_min = 64,
    .period_bytes_max = (128*1024),
    .periods_min =      2,
    .periods_max =      1024,
    .fifo_size =              0
};



static int snd_usX2Y_pcm_open(struct snd_pcm_substream *substream)
{
    struct snd_usX2Y_substream  *subs = ((struct snd_usX2Y_substream **)
                     snd_pcm_substream_chip(substream))[substream->stream];
    struct snd_pcm_runtime  *runtime = substream->runtime;

    if (subs->usX2Y->chip_status & USX2Y_STAT_CHIP_MMAP_PCM_URBS)
        return -EBUSY;

    runtime->hw = snd_usX2Y_2c;
    runtime->private_data = subs;
    subs->pcm_substream = substream;
    snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME, 1000, 200000);
    return 0;
}



static int snd_usX2Y_pcm_close(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct snd_usX2Y_substream *subs = runtime->private_data;

    subs->pcm_substream = NULL;

    return 0;
}


static struct snd_pcm_ops snd_usX2Y_pcm_ops = 
{
    .open =     snd_usX2Y_pcm_open,
    .close =    snd_usX2Y_pcm_close,
    .ioctl =    snd_pcm_lib_ioctl,
    .hw_params =    snd_usX2Y_pcm_hw_params,
    .hw_free =  snd_usX2Y_pcm_hw_free,
    .prepare =  snd_usX2Y_pcm_prepare,
    .trigger =  snd_usX2Y_pcm_trigger,
    .pointer =  snd_usX2Y_pcm_pointer,
};


/*
 * free a usb stream instance
 */
static void usX2Y_audio_stream_free(struct snd_usX2Y_substream **usX2Y_substream)
{
    kfree(usX2Y_substream[SNDRV_PCM_STREAM_PLAYBACK]);
    usX2Y_substream[SNDRV_PCM_STREAM_PLAYBACK] = NULL;

    kfree(usX2Y_substream[SNDRV_PCM_STREAM_CAPTURE]);
    usX2Y_substream[SNDRV_PCM_STREAM_CAPTURE] = NULL;
}

static void snd_usX2Y_pcm_private_free(struct snd_pcm *pcm)
{
    struct snd_usX2Y_substream **usX2Y_stream = pcm->private_data;
    if (usX2Y_stream)
        usX2Y_audio_stream_free(usX2Y_stream);
}

static int usX2Y_audio_stream_new(struct snd_card *card, int playback_endpoint, int capture_endpoint)
{
    struct snd_pcm *pcm;
    int err, i;
    struct snd_usX2Y_substream **usX2Y_substream =
        usX2Y(card)->subs + 2 * usX2Y(card)->pcm_devs;

    for (i = playback_endpoint ? SNDRV_PCM_STREAM_PLAYBACK : SNDRV_PCM_STREAM_CAPTURE;
         i <= SNDRV_PCM_STREAM_CAPTURE; ++i) {
        usX2Y_substream[i] = kzalloc(sizeof(struct snd_usX2Y_substream), GFP_KERNEL);
        if (NULL == usX2Y_substream[i]) {
            snd_printk(KERN_ERR "cannot malloc\n");
            return -ENOMEM;
        }
        usX2Y_substream[i]->usX2Y = usX2Y(card);
    }

    if (playback_endpoint)
        usX2Y_substream[SNDRV_PCM_STREAM_PLAYBACK]->endpoint = playback_endpoint;
    usX2Y_substream[SNDRV_PCM_STREAM_CAPTURE]->endpoint = capture_endpoint;

    err = snd_pcm_new(card, NAME_ALLCAPS" Audio", usX2Y(card)->pcm_devs,
              playback_endpoint ? 1 : 0, 1,
              &pcm);
    if (err < 0) {
        usX2Y_audio_stream_free(usX2Y_substream);
        return err;
    }

    if (playback_endpoint)
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_usX2Y_pcm_ops);
    snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_usX2Y_pcm_ops);

    pcm->private_data = usX2Y_substream;
    pcm->private_free = snd_usX2Y_pcm_private_free;
    pcm->info_flags = 0;

    sprintf(pcm->name, NAME_ALLCAPS" Audio #%d", usX2Y(card)->pcm_devs);

    if ((playback_endpoint &&
         0 > (err = snd_pcm_lib_preallocate_pages(pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream,
                             SNDRV_DMA_TYPE_CONTINUOUS,
                             snd_dma_continuous_data(GFP_KERNEL),
                             64*1024, 128*1024))) ||
        0 > (err = snd_pcm_lib_preallocate_pages(pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream,
                                 SNDRV_DMA_TYPE_CONTINUOUS,
                                 snd_dma_continuous_data(GFP_KERNEL),
                             64*1024, 128*1024))) {
        snd_usX2Y_pcm_private_free(pcm);
        return err;
    }
    usX2Y(card)->pcm_devs++;

    return 0;
}

/*
 * create a chip instance and set its names.
 */
int usX2Y_audio_create(struct snd_card *card)
{
    int err = 0;
    
    INIT_LIST_HEAD(&usX2Y(card)->pcm_list);

    if (0 > (err = usX2Y_audio_stream_new(card, 0xA, 0x8)))
        return err;
    if (le16_to_cpu(usX2Y(card)->dev->descriptor.idProduct) == USB_ID_US428)
         if (0 > (err = usX2Y_audio_stream_new(card, 0, 0xA)))
             return err;
    if (le16_to_cpu(usX2Y(card)->dev->descriptor.idProduct) != USB_ID_US122)
        err = usX2Y_rate_set(usX2Y(card), 44100);   // Lets us428 recognize output-volume settings, disturbs us122.
    return err;
}