// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   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 <tiwai@suse.de>
 *
 *   Many codes borrowed from audio.c by
 *          Alan Cox (alan@lxorguk.ukuu.org.uk)
 *          Thomas Sailer (sailer@ife.ee.ethz.ch)
 */


#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"

/* 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 4

/* 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.
 */
#define USX2Y_NRPACKS_VARIABLE 1

#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;
        int             cnt, blen;
        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) {
                        cnt = runtime->buffer_size - hwptr_done;
                        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;
                hwptr_done += len;
                if (hwptr_done >= 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)
{
        struct usx2ydev *usx2y = subs->usx2y;
        struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
        int count, counts, pack, len;

        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.
                         */
                        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;
                        subs->hwptr += count;
                        if (subs->hwptr >= 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 */
        err = usb_submit_urb(urb, GFP_ATOMIC);
        if (err < 0) {
                snd_printk(KERN_ERR "usb_submit_urb() returned %i\n", err);
                return err;
        }
        return 0;
}

static 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 (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) {
                err = usx2y_urb_play_prepare(playbacksubs, capsubs->completed_urb, urb);
                if (err)
                        return err;
                err = usx2y_urb_submit(playbacksubs, urb, frame);
                if (err)
                        return err;
        }

        playbacksubs->completed_urb = NULL;

        state = atomic_read(&capsubs->state);
        if (state >= STATE_PREPARED) {
                if (state == STATE_RUNNING) {
                        err = usx2y_urb_capt_retire(capsubs);
                        if (err)
                                return err;
                } else if (state >= STATE_PRERUNNING) {
                        atomic_inc(&capsubs->state);
                }
                err = usx2y_urb_submit(capsubs, capsubs->completed_urb, frame);
                if (err)
                        return err;
        }
        capsubs->completed_urb = NULL;
        return 0;
}

static void usx2y_clients_stop(struct usx2ydev *usx2y)
{
        struct snd_usx2y_substream *subs;
        struct urb *urb;
        int s, u;

        for (s = 0; s < 4; s++) {
                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++) {
                subs = usx2y->subs[s];
                if (subs) {
                        if (atomic_read(&subs->state) >= STATE_PRERUNNING)
                                snd_pcm_stop_xrun(subs->pcm_substream);
                        for (u = 0; u < NRURBS; u++) {
                                urb = subs->urb[u];
                                if (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 i_usx2y_urb_complete(struct urb *urb)
{
        struct snd_usx2y_substream *subs = urb->context;
        struct usx2ydev *usx2y = subs->usx2y;
        struct snd_usx2y_substream *capsubs, *playbacksubs;

        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;
        }

        subs->completed_urb = urb;

        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 *))
{
        struct snd_usx2y_substream *subs;
        struct urb *urb;
        int s, u;

        for (s = 0; s < 4; s++) {
                subs = usx2y->subs[s];
                if (subs) {
                        for (u = 0; u < NRURBS; u++) {
                                urb = subs->urb[u];
                                if (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 (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("%s %i\n", __func__, 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;
        struct urb **purb;

        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 && !subs->tmpbuf) {     /* allocate a temporary buffer for playback */
                subs->tmpbuf = kcalloc(nr_of_packs(), subs->maxpacksize, GFP_KERNEL);
                if (!subs->tmpbuf)
                        return -ENOMEM;
        }
        /* allocate and initialize data urbs */
        for (i = 0; i < NRURBS; i++) {
                purb = subs->urb + i;
                if (*purb) {
                        usb_kill_urb(*purb);
                        continue;
                }
                *purb = usb_alloc_urb(nr_of_packs(), GFP_KERNEL);
                if (!*purb) {
                        usx2y_urbs_release(subs);
                        return -ENOMEM;
                }
                if (!is_playback && !(*purb)->transfer_buffer) {
                        /* allocate a capture buffer per urb */
                        (*purb)->transfer_buffer =
                                kmalloc_array(subs->maxpacksize,
                                              nr_of_packs(), GFP_KERNEL);
                        if (!(*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;
        struct urb *urb;
        unsigned long pack;

        err = usx2y_urbs_allocate(subs);
        if (err < 0)
                return err;
        subs->completed_urb = NULL;
        for (i = 0; i < 4; i++) {
                struct snd_usx2y_substream *subs = usx2y->subs[i];

                if (subs && atomic_read(&subs->state) >= STATE_PREPARED)
                        goto start;
        }

 start:
        usx2y_subs_startup(subs);
        for (i = 0; i < NRURBS; i++) {
                urb = subs->urb[i];
                if (usb_pipein(urb->pipe)) {
                        if (!i)
                                atomic_set(&subs->state, STATE_STARTING3);
                        urb->dev = usx2y->dev;
                        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();
                        err = usb_submit_urb(urb, GFP_ATOMIC);
                        if (err < 0) {
                                snd_printk(KERN_ERR "cannot submit datapipe for urb %d, err = %d\n", i, err);
                                err = -EPIPE;
                                goto cleanup;
                        } else {
                                if (!i)
                                        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, !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 wrong > stop everything
        }
        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("%s(START)\n", __func__);
                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("%s(STOP)\n", __func__);
                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.
 */
struct s_c2 {
        char c1, c2;
};

static const struct s_c2 setrate_44100[] = {
        { 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 const struct s_c2 setrate_48000[] = {
        { 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(setrate_48000)

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 (!--usx2y->us04->len)
                wake_up(&usx2y->in04_wait_queue);
}

static int usx2y_rate_set(struct usx2ydev *usx2y, int rate)
{
        int                     err = 0, i;
        struct snd_usx2y_urb_seq        *us = NULL;
        int                     *usbdata = NULL;
        const struct s_c2       *ra = rate == 48000 ? setrate_48000 : setrate_44100;
        struct urb *urb;

        if (usx2y->rate != rate) {
                us = kzalloc(sizeof(*us) + sizeof(struct urb *) * NOOF_SETRATE_URBS, GFP_KERNEL);
                if (!us) {
                        err = -ENOMEM;
                        goto cleanup;
                }
                usbdata = kmalloc_array(NOOF_SETRATE_URBS, sizeof(int),
                                        GFP_KERNEL);
                if (!usbdata) {
                        err = -ENOMEM;
                        goto cleanup;
                }
                for (i = 0; i < NOOF_SETRATE_URBS; ++i) {
                        us->urb[i] = usb_alloc_urb(0, GFP_KERNEL);
                        if (!us->urb[i]) {
                                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);
                }
                err = usb_urb_ep_type_check(us->urb[0]);
                if (err < 0)
                        goto cleanup;
                us->submitted = 0;
                us->len =       NOOF_SETRATE_URBS;
                usx2y->us04 =   us;
                wait_event_timeout(usx2y->in04_wait_queue, !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) {
                                urb = us->urb[i];
                                if (!urb)
                                        continue;
                                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->in04_urb);
        err = usb_set_interface(usx2y->dev, 0, alternate);
        if (err) {
                snd_printk(KERN_ERR "usb_set_interface error\n");
                return err;
        }
        usx2y->in04_urb->dev = usx2y->dev;
        err = usb_submit_urb(usx2y->in04_urb, 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 usx2ydev *dev = usx2y(card);
        struct snd_usx2y_substream *subs;
        struct snd_pcm_substream *test_substream;
        int i;

        mutex_lock(&usx2y(card)->pcm_mutex);
        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
         */
        for (i = 0; i < dev->pcm_devs * 2; i++) {
                subs = dev->subs[i];
                if (!subs)
                        continue;
                test_substream = subs->pcm_substream;
                if (!test_substream || test_substream == substream ||
                    !test_substream->runtime)
                        continue;
                if ((test_substream->runtime->format &&
                     test_substream->runtime->format != format) ||
                    (test_substream->runtime->rate &&
                     test_substream->runtime->rate != rate)) {
                        err = -EINVAL;
                        goto error;
                }
        }

 error:
        mutex_unlock(&usx2y(card)->pcm_mutex);
        return err;
}

/*
 * 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;
        struct snd_usx2y_substream *cap_subs, *playback_subs;

        mutex_lock(&subs->usx2y->pcm_mutex);
        snd_printdd("snd_usx2y_hw_free(%p)\n", substream);

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                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 {
                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->pcm_mutex);
        return 0;
}

/*
 * 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("%s(%p)\n", __func__, substream);

        mutex_lock(&usx2y->pcm_mutex);
        usx2y_subs_prepare(subs);
        // Start hardware streams
        // SyncStream first....
        if (atomic_read(&capsubs->state) < STATE_PREPARED) {
                if (usx2y->format != runtime->format) {
                        err = usx2y_format_set(usx2y, runtime->format);
                        if (err < 0)
                                goto up_prepare_mutex;
                }
                if (usx2y->rate != runtime->rate) {
                        err = usx2y_rate_set(usx2y, runtime->rate);
                        if (err < 0)
                                goto up_prepare_mutex;
                }
                snd_printdd("starting capture pipe for %s\n", subs == capsubs ? "self" : "playpipe");
                err = usx2y_urbs_start(capsubs);
                if (err < 0)
                        goto up_prepare_mutex;
        }

        if (subs != capsubs && atomic_read(&subs->state) < STATE_PREPARED)
                err = usx2y_urbs_start(subs);

 up_prepare_mutex:
        mutex_unlock(&usx2y->pcm_mutex);
        return err;
}

static const 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 const struct snd_pcm_ops snd_usx2y_pcm_ops = {
        .open =         snd_usx2y_pcm_open,
        .close =        snd_usx2y_pcm_close,
        .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)
{
        int stream;

        for_each_pcm_streams(stream) {
                kfree(usx2y_substream[stream]);
                usx2y_substream[stream] = 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 (!usx2y_substream[i])
                        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) {
                snd_pcm_set_managed_buffer(pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream,

                                           SNDRV_DMA_TYPE_CONTINUOUS,
                                           NULL,
                                           64*1024, 128*1024);
        }

        snd_pcm_set_managed_buffer(pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream,
                                   SNDRV_DMA_TYPE_CONTINUOUS,
                                   NULL,
                                   64*1024, 128*1024);
        usx2y(card)->pcm_devs++;

        return 0;
}

/*
 * create a chip instance and set its names.
 */
int usx2y_audio_create(struct snd_card *card)
{
        int err;

        err = usx2y_audio_stream_new(card, 0xA, 0x8);
        if (err < 0)
                return err;
        if (le16_to_cpu(usx2y(card)->dev->descriptor.idProduct) == USB_ID_US428) {
                err = usx2y_audio_stream_new(card, 0, 0xA);
                if (err < 0)
                        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;
}