/*
   *   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)
   *
   *
   *   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 propably some hardware problem.
  ",
  				   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!
  ");
  			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
  ", 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
  ", 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
  ", 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
  ",
  						    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
  ", 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).
  "
  "Most propably some urb of usb-frame %i is still missing.
  "
  "Cause could be too long delays in usb-hcd interrupt handling.
  ",

  		   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
  ",

  			    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("
  ");
  				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
  ",
  		    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
  ", 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
  ");
  			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
  ", 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)
  ");
  		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("
  ");
  			return -EPIPE;
  		}
  		break;
  	case SNDRV_PCM_TRIGGER_STOP:
  		snd_printdd("snd_usX2Y_pcm_trigger(STOP)
  ");
  		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
  ", 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 
  ");

  		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)
  ", 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
  ",
  			   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)
  ", 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)
  ", 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
  ", 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
  ");
  			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;
  }