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

  #include <linux/slab.h>

  #include <linux/usb.h>
  #include <linux/usb/audio.h>

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

  
  #include <sound/core.h>
  #include <sound/pcm.h>
  #include <sound/pcm_params.h>
  
  #include "usbaudio.h"
  #include "card.h"
  #include "quirks.h"
  #include "debug.h"
  #include "urb.h"
  #include "helper.h"
  #include "pcm.h"

  #include "clock.h"

  #include "power.h"

  
  /*
   * return the current pcm pointer.  just based on the hwptr_done value.
   */
  static snd_pcm_uframes_t snd_usb_pcm_pointer(struct snd_pcm_substream *substream)
  {
  	struct snd_usb_substream *subs;
  	unsigned int hwptr_done;
  
  	subs = (struct snd_usb_substream *)substream->runtime->private_data;
  	spin_lock(&subs->lock);
  	hwptr_done = subs->hwptr_done;
  	spin_unlock(&subs->lock);
  	return hwptr_done / (substream->runtime->frame_bits >> 3);
  }
  
  /*
   * find a matching audio format
   */
  static struct audioformat *find_format(struct snd_usb_substream *subs, unsigned int format,
  				       unsigned int rate, unsigned int channels)
  {
  	struct list_head *p;
  	struct audioformat *found = NULL;
  	int cur_attr = 0, attr;
  
  	list_for_each(p, &subs->fmt_list) {
  		struct audioformat *fp;
  		fp = list_entry(p, struct audioformat, list);

  		if (!(fp->formats & (1uLL << format)))
  			continue;
  		if (fp->channels != channels)

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

  static int init_pitch_v1(struct snd_usb_audio *chip, int iface,
  			 struct usb_host_interface *alts,
  			 struct audioformat *fmt)
  {
  	struct usb_device *dev = chip->dev;
  	unsigned int ep;
  	unsigned char data[1];
  	int err;
  
  	ep = get_endpoint(alts, 0)->bEndpointAddress;

  	data[0] = 1;
  	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC_SET_CUR,
  				   USB_TYPE_CLASS|USB_RECIP_ENDPOINT|USB_DIR_OUT,
  				   UAC_EP_CS_ATTR_PITCH_CONTROL << 8, ep,
  				   data, sizeof(data), 1000)) < 0) {
  		snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH
  ",
  			   dev->devnum, iface, ep);
  		return err;
  	}
  
  	return 0;
  }

  static int init_pitch_v2(struct snd_usb_audio *chip, int iface,
  			 struct usb_host_interface *alts,
  			 struct audioformat *fmt)
  {
  	struct usb_device *dev = chip->dev;
  	unsigned char data[1];
  	unsigned int ep;
  	int err;
  
  	ep = get_endpoint(alts, 0)->bEndpointAddress;
  
  	data[0] = 1;
  	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
  				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_OUT,
  				   UAC2_EP_CS_PITCH << 8, 0,
  				   data, sizeof(data), 1000)) < 0) {
  		snd_printk(KERN_ERR "%d:%d:%d: cannot set enable PITCH (v2)
  ",
  			   dev->devnum, iface, fmt->altsetting);
  		return err;
  	}
  
  	return 0;
  }

  /*

   * initialize the pitch control and sample rate

   */

  int snd_usb_init_pitch(struct snd_usb_audio *chip, int iface,

  		       struct usb_host_interface *alts,
  		       struct audioformat *fmt)
  {

  	struct usb_interface_descriptor *altsd = get_iface_desc(alts);

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

  	switch (altsd->bInterfaceProtocol) {
  	case UAC_VERSION_1:

  	default:

  		return init_pitch_v1(chip, iface, alts, fmt);
  
  	case UAC_VERSION_2:

  		return init_pitch_v2(chip, iface, alts, fmt);

  	}

  }

  /*
   * find a matching format and set up the interface
   */
  static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
  {
  	struct usb_device *dev = subs->dev;
  	struct usb_host_interface *alts;
  	struct usb_interface_descriptor *altsd;
  	struct usb_interface *iface;
  	unsigned int ep, attr;
  	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;
  	int err;
  
  	iface = usb_ifnum_to_if(dev, fmt->iface);
  	if (WARN_ON(!iface))
  		return -EINVAL;
  	alts = &iface->altsetting[fmt->altset_idx];
  	altsd = get_iface_desc(alts);
  	if (WARN_ON(altsd->bAlternateSetting != fmt->altsetting))
  		return -EINVAL;
  
  	if (fmt == subs->cur_audiofmt)
  		return 0;
  
  	/* close the old interface */
  	if (subs->interface >= 0 && subs->interface != fmt->iface) {
  		if (usb_set_interface(subs->dev, subs->interface, 0) < 0) {
  			snd_printk(KERN_ERR "%d:%d:%d: return to setting 0 failed
  ",
  				dev->devnum, fmt->iface, fmt->altsetting);
  			return -EIO;
  		}
  		subs->interface = -1;

  		subs->altset_idx = 0;

  	}
  
  	/* set interface */

  	if (subs->interface != fmt->iface || subs->altset_idx != fmt->altset_idx) {

  		if (usb_set_interface(dev, fmt->iface, fmt->altsetting) < 0) {
  			snd_printk(KERN_ERR "%d:%d:%d: usb_set_interface failed
  ",
  				   dev->devnum, fmt->iface, fmt->altsetting);
  			return -EIO;
  		}
  		snd_printdd(KERN_INFO "setting usb interface %d:%d
  ", fmt->iface, fmt->altsetting);
  		subs->interface = fmt->iface;

  		subs->altset_idx = fmt->altset_idx;

  	}
  
  	/* create a data pipe */
  	ep = fmt->endpoint & USB_ENDPOINT_NUMBER_MASK;
  	if (is_playback)
  		subs->datapipe = usb_sndisocpipe(dev, ep);
  	else
  		subs->datapipe = usb_rcvisocpipe(dev, ep);
  	subs->datainterval = fmt->datainterval;
  	subs->syncpipe = subs->syncinterval = 0;
  	subs->maxpacksize = fmt->maxpacksize;

  	subs->syncmaxsize = 0;

  	subs->fill_max = 0;
  
  	/* we need a sync pipe in async OUT or adaptive IN mode */
  	/* check the number of EP, since some devices have broken
  	 * descriptors which fool us.  if it has only one EP,
  	 * assume it as adaptive-out or sync-in.
  	 */
  	attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;
  	if (((is_playback && attr == USB_ENDPOINT_SYNC_ASYNC) ||
  	     (! is_playback && attr == USB_ENDPOINT_SYNC_ADAPTIVE)) &&
  	    altsd->bNumEndpoints >= 2) {
  		/* check sync-pipe endpoint */
  		/* ... and check descriptor size before accessing bSynchAddress
  		   because there is a version of the SB Audigy 2 NX firmware lacking
  		   the audio fields in the endpoint descriptors */
  		if ((get_endpoint(alts, 1)->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) != 0x01 ||
  		    (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
  		     get_endpoint(alts, 1)->bSynchAddress != 0)) {
  			snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe
  ",
  				   dev->devnum, fmt->iface, fmt->altsetting);
  			return -EINVAL;
  		}
  		ep = get_endpoint(alts, 1)->bEndpointAddress;
  		if (get_endpoint(alts, 0)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
  		    (( is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress | USB_DIR_IN)) ||
  		     (!is_playback && ep != (unsigned int)(get_endpoint(alts, 0)->bSynchAddress & ~USB_DIR_IN)))) {
  			snd_printk(KERN_ERR "%d:%d:%d : invalid synch pipe
  ",
  				   dev->devnum, fmt->iface, fmt->altsetting);
  			return -EINVAL;
  		}
  		ep &= USB_ENDPOINT_NUMBER_MASK;
  		if (is_playback)
  			subs->syncpipe = usb_rcvisocpipe(dev, ep);
  		else
  			subs->syncpipe = usb_sndisocpipe(dev, ep);
  		if (get_endpoint(alts, 1)->bLength >= USB_DT_ENDPOINT_AUDIO_SIZE &&
  		    get_endpoint(alts, 1)->bRefresh >= 1 &&
  		    get_endpoint(alts, 1)->bRefresh <= 9)
  			subs->syncinterval = get_endpoint(alts, 1)->bRefresh;
  		else if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)
  			subs->syncinterval = 1;
  		else if (get_endpoint(alts, 1)->bInterval >= 1 &&
  			 get_endpoint(alts, 1)->bInterval <= 16)
  			subs->syncinterval = get_endpoint(alts, 1)->bInterval - 1;
  		else
  			subs->syncinterval = 3;

  		subs->syncmaxsize = le16_to_cpu(get_endpoint(alts, 1)->wMaxPacketSize);

  	}
  
  	/* always fill max packet size */
  	if (fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX)
  		subs->fill_max = 1;

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

  		return err;
  
  	subs->cur_audiofmt = fmt;
  
  	snd_usb_set_format_quirk(subs, fmt);
  
  #if 0
  	printk(KERN_DEBUG
  	       "setting done: format = %d, rate = %d..%d, channels = %d
  ",
  	       fmt->format, fmt->rate_min, fmt->rate_max, fmt->channels);
  	printk(KERN_DEBUG
  	       "  datapipe = 0x%0x, syncpipe = 0x%0x
  ",
  	       subs->datapipe, subs->syncpipe);
  #endif
  
  	return 0;
  }
  
  /*
   * hw_params callback
   *
   * allocate a buffer and set the given audio format.
   *
   * so far we use a physically linear buffer although packetize transfer
   * doesn't need a continuous area.
   * if sg buffer is supported on the later version of alsa, we'll follow
   * that.
   */
  static int snd_usb_hw_params(struct snd_pcm_substream *substream,
  			     struct snd_pcm_hw_params *hw_params)
  {
  	struct snd_usb_substream *subs = substream->runtime->private_data;
  	struct audioformat *fmt;
  	unsigned int channels, rate, format;
  	int ret, changed;
  
  	ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
  					       params_buffer_bytes(hw_params));
  	if (ret < 0)
  		return ret;
  
  	format = params_format(hw_params);
  	rate = params_rate(hw_params);
  	channels = params_channels(hw_params);
  	fmt = find_format(subs, format, rate, channels);
  	if (!fmt) {
  		snd_printd(KERN_DEBUG "cannot set format: format = %#x, rate = %d, channels = %d
  ",
  			   format, rate, channels);
  		return -EINVAL;
  	}
  
  	changed = subs->cur_audiofmt != fmt ||
  		subs->period_bytes != params_period_bytes(hw_params) ||
  		subs->cur_rate != rate;
  	if ((ret = set_format(subs, fmt)) < 0)
  		return ret;
  
  	if (subs->cur_rate != rate) {
  		struct usb_host_interface *alts;
  		struct usb_interface *iface;
  		iface = usb_ifnum_to_if(subs->dev, fmt->iface);
  		alts = &iface->altsetting[fmt->altset_idx];

  		ret = snd_usb_init_sample_rate(subs->stream->chip, subs->interface, alts, fmt, rate);

  		if (ret < 0)
  			return ret;
  		subs->cur_rate = rate;
  	}
  
  	if (changed) {

  		mutex_lock(&subs->stream->chip->shutdown_mutex);

  		/* format changed */
  		snd_usb_release_substream_urbs(subs, 0);
  		/* influenced: period_bytes, channels, rate, format, */
  		ret = snd_usb_init_substream_urbs(subs, params_period_bytes(hw_params),
  						  params_rate(hw_params),
  						  snd_pcm_format_physical_width(params_format(hw_params)) *
  							params_channels(hw_params));

  		mutex_unlock(&subs->stream->chip->shutdown_mutex);

  	}
  
  	return ret;
  }
  
  /*
   * hw_free callback
   *
   * reset the audio format and release the buffer
   */
  static int snd_usb_hw_free(struct snd_pcm_substream *substream)
  {
  	struct snd_usb_substream *subs = substream->runtime->private_data;
  
  	subs->cur_audiofmt = NULL;
  	subs->cur_rate = 0;
  	subs->period_bytes = 0;

  	mutex_lock(&subs->stream->chip->shutdown_mutex);
  	snd_usb_release_substream_urbs(subs, 0);
  	mutex_unlock(&subs->stream->chip->shutdown_mutex);

  	return snd_pcm_lib_free_vmalloc_buffer(substream);
  }
  
  /*
   * prepare callback
   *
   * only a few subtle things...
   */
  static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct snd_usb_substream *subs = runtime->private_data;
  
  	if (! subs->cur_audiofmt) {
  		snd_printk(KERN_ERR "usbaudio: no format is specified!
  ");
  		return -ENXIO;
  	}
  
  	/* some unit conversions in runtime */
  	subs->maxframesize = bytes_to_frames(runtime, subs->maxpacksize);
  	subs->curframesize = bytes_to_frames(runtime, subs->curpacksize);
  
  	/* reset the pointer */
  	subs->hwptr_done = 0;
  	subs->transfer_done = 0;
  	subs->phase = 0;
  	runtime->delay = 0;
  
  	return snd_usb_substream_prepare(subs, runtime);
  }
  
  static struct snd_pcm_hardware snd_usb_hardware =
  {
  	.info =			SNDRV_PCM_INFO_MMAP |
  				SNDRV_PCM_INFO_MMAP_VALID |
  				SNDRV_PCM_INFO_BATCH |
  				SNDRV_PCM_INFO_INTERLEAVED |
  				SNDRV_PCM_INFO_BLOCK_TRANSFER |
  				SNDRV_PCM_INFO_PAUSE,
  	.buffer_bytes_max =	1024 * 1024,
  	.period_bytes_min =	64,
  	.period_bytes_max =	512 * 1024,
  	.periods_min =		2,
  	.periods_max =		1024,
  };
  
  static int hw_check_valid_format(struct snd_usb_substream *subs,
  				 struct snd_pcm_hw_params *params,
  				 struct audioformat *fp)
  {
  	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
  	struct snd_interval *ct = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
  	struct snd_mask *fmts = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
  	struct snd_interval *pt = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);

  	struct snd_mask check_fmts;

  	unsigned int ptime;
  
  	/* check the format */

  	snd_mask_none(&check_fmts);
  	check_fmts.bits[0] = (u32)fp->formats;
  	check_fmts.bits[1] = (u32)(fp->formats >> 32);
  	snd_mask_intersect(&check_fmts, fmts);
  	if (snd_mask_empty(&check_fmts)) {

  		hwc_debug("   > check: no supported format %d
  ", fp->format);
  		return 0;
  	}
  	/* check the channels */
  	if (fp->channels < ct->min || fp->channels > ct->max) {
  		hwc_debug("   > check: no valid channels %d (%d/%d)
  ", fp->channels, ct->min, ct->max);
  		return 0;
  	}
  	/* check the rate is within the range */
  	if (fp->rate_min > it->max || (fp->rate_min == it->max && it->openmax)) {
  		hwc_debug("   > check: rate_min %d > max %d
  ", fp->rate_min, it->max);
  		return 0;
  	}
  	if (fp->rate_max < it->min || (fp->rate_max == it->min && it->openmin)) {
  		hwc_debug("   > check: rate_max %d < min %d
  ", fp->rate_max, it->min);
  		return 0;
  	}
  	/* check whether the period time is >= the data packet interval */

  	if (snd_usb_get_speed(subs->dev) != USB_SPEED_FULL) {

  		ptime = 125 * (1 << fp->datainterval);
  		if (ptime > pt->max || (ptime == pt->max && pt->openmax)) {
  			hwc_debug("   > check: ptime %u > max %u
  ", ptime, pt->max);
  			return 0;
  		}
  	}
  	return 1;
  }
  
  static int hw_rule_rate(struct snd_pcm_hw_params *params,
  			struct snd_pcm_hw_rule *rule)
  {
  	struct snd_usb_substream *subs = rule->private;
  	struct list_head *p;
  	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
  	unsigned int rmin, rmax;
  	int changed;
  
  	hwc_debug("hw_rule_rate: (%d,%d)
  ", it->min, it->max);
  	changed = 0;
  	rmin = rmax = 0;
  	list_for_each(p, &subs->fmt_list) {
  		struct audioformat *fp;
  		fp = list_entry(p, struct audioformat, list);
  		if (!hw_check_valid_format(subs, params, fp))
  			continue;
  		if (changed++) {
  			if (rmin > fp->rate_min)
  				rmin = fp->rate_min;
  			if (rmax < fp->rate_max)
  				rmax = fp->rate_max;
  		} else {
  			rmin = fp->rate_min;
  			rmax = fp->rate_max;
  		}
  	}
  
  	if (!changed) {
  		hwc_debug("  --> get empty
  ");
  		it->empty = 1;
  		return -EINVAL;
  	}
  
  	changed = 0;
  	if (it->min < rmin) {
  		it->min = rmin;
  		it->openmin = 0;
  		changed = 1;
  	}
  	if (it->max > rmax) {
  		it->max = rmax;
  		it->openmax = 0;
  		changed = 1;
  	}
  	if (snd_interval_checkempty(it)) {
  		it->empty = 1;
  		return -EINVAL;
  	}
  	hwc_debug("  --> (%d, %d) (changed = %d)
  ", it->min, it->max, changed);
  	return changed;
  }
  
  
  static int hw_rule_channels(struct snd_pcm_hw_params *params,
  			    struct snd_pcm_hw_rule *rule)
  {
  	struct snd_usb_substream *subs = rule->private;
  	struct list_head *p;
  	struct snd_interval *it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
  	unsigned int rmin, rmax;
  	int changed;
  
  	hwc_debug("hw_rule_channels: (%d,%d)
  ", it->min, it->max);
  	changed = 0;
  	rmin = rmax = 0;
  	list_for_each(p, &subs->fmt_list) {
  		struct audioformat *fp;
  		fp = list_entry(p, struct audioformat, list);
  		if (!hw_check_valid_format(subs, params, fp))
  			continue;
  		if (changed++) {
  			if (rmin > fp->channels)
  				rmin = fp->channels;
  			if (rmax < fp->channels)
  				rmax = fp->channels;
  		} else {
  			rmin = fp->channels;
  			rmax = fp->channels;
  		}
  	}
  
  	if (!changed) {
  		hwc_debug("  --> get empty
  ");
  		it->empty = 1;
  		return -EINVAL;
  	}
  
  	changed = 0;
  	if (it->min < rmin) {
  		it->min = rmin;
  		it->openmin = 0;
  		changed = 1;
  	}
  	if (it->max > rmax) {
  		it->max = rmax;
  		it->openmax = 0;
  		changed = 1;
  	}
  	if (snd_interval_checkempty(it)) {
  		it->empty = 1;
  		return -EINVAL;
  	}
  	hwc_debug("  --> (%d, %d) (changed = %d)
  ", it->min, it->max, changed);
  	return changed;
  }
  
  static int hw_rule_format(struct snd_pcm_hw_params *params,
  			  struct snd_pcm_hw_rule *rule)
  {
  	struct snd_usb_substream *subs = rule->private;
  	struct list_head *p;
  	struct snd_mask *fmt = hw_param_mask(params, SNDRV_PCM_HW_PARAM_FORMAT);
  	u64 fbits;
  	u32 oldbits[2];
  	int changed;
  
  	hwc_debug("hw_rule_format: %x:%x
  ", fmt->bits[0], fmt->bits[1]);
  	fbits = 0;
  	list_for_each(p, &subs->fmt_list) {
  		struct audioformat *fp;
  		fp = list_entry(p, struct audioformat, list);
  		if (!hw_check_valid_format(subs, params, fp))
  			continue;

  		fbits |= fp->formats;

  	}
  
  	oldbits[0] = fmt->bits[0];
  	oldbits[1] = fmt->bits[1];
  	fmt->bits[0] &= (u32)fbits;
  	fmt->bits[1] &= (u32)(fbits >> 32);
  	if (!fmt->bits[0] && !fmt->bits[1]) {
  		hwc_debug("  --> get empty
  ");
  		return -EINVAL;
  	}
  	changed = (oldbits[0] != fmt->bits[0] || oldbits[1] != fmt->bits[1]);
  	hwc_debug("  --> %x:%x (changed = %d)
  ", fmt->bits[0], fmt->bits[1], changed);
  	return changed;
  }
  
  static int hw_rule_period_time(struct snd_pcm_hw_params *params,
  			       struct snd_pcm_hw_rule *rule)
  {
  	struct snd_usb_substream *subs = rule->private;
  	struct audioformat *fp;
  	struct snd_interval *it;
  	unsigned char min_datainterval;
  	unsigned int pmin;
  	int changed;
  
  	it = hw_param_interval(params, SNDRV_PCM_HW_PARAM_PERIOD_TIME);
  	hwc_debug("hw_rule_period_time: (%u,%u)
  ", it->min, it->max);
  	min_datainterval = 0xff;
  	list_for_each_entry(fp, &subs->fmt_list, list) {
  		if (!hw_check_valid_format(subs, params, fp))
  			continue;
  		min_datainterval = min(min_datainterval, fp->datainterval);
  	}
  	if (min_datainterval == 0xff) {

  		hwc_debug("  --> get empty
  ");

  		it->empty = 1;
  		return -EINVAL;
  	}
  	pmin = 125 * (1 << min_datainterval);
  	changed = 0;
  	if (it->min < pmin) {
  		it->min = pmin;
  		it->openmin = 0;
  		changed = 1;
  	}
  	if (snd_interval_checkempty(it)) {
  		it->empty = 1;
  		return -EINVAL;
  	}
  	hwc_debug("  --> (%u,%u) (changed = %d)
  ", it->min, it->max, changed);
  	return changed;
  }
  
  /*
   *  If the device supports unusual bit rates, does the request meet these?
   */
  static int snd_usb_pcm_check_knot(struct snd_pcm_runtime *runtime,
  				  struct snd_usb_substream *subs)
  {
  	struct audioformat *fp;
  	int count = 0, needs_knot = 0;
  	int err;
  
  	list_for_each_entry(fp, &subs->fmt_list, list) {
  		if (fp->rates & SNDRV_PCM_RATE_CONTINUOUS)
  			return 0;
  		count += fp->nr_rates;
  		if (fp->rates & SNDRV_PCM_RATE_KNOT)
  			needs_knot = 1;
  	}
  	if (!needs_knot)
  		return 0;

  	subs->rate_list.list = kmalloc(sizeof(int) * count, GFP_KERNEL);

  	if (!subs->rate_list.list)
  		return -ENOMEM;
  	subs->rate_list.count = count;

  	subs->rate_list.mask = 0;
  	count = 0;
  	list_for_each_entry(fp, &subs->fmt_list, list) {
  		int i;
  		for (i = 0; i < fp->nr_rates; i++)
  			subs->rate_list.list[count++] = fp->rate_table[i];
  	}
  	err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
  					 &subs->rate_list);
  	if (err < 0)
  		return err;
  
  	return 0;
  }
  
  
  /*
   * set up the runtime hardware information.
   */
  
  static int setup_hw_info(struct snd_pcm_runtime *runtime, struct snd_usb_substream *subs)
  {
  	struct list_head *p;
  	unsigned int pt, ptmin;
  	int param_period_time_if_needed;
  	int err;
  
  	runtime->hw.formats = subs->formats;
  
  	runtime->hw.rate_min = 0x7fffffff;
  	runtime->hw.rate_max = 0;
  	runtime->hw.channels_min = 256;
  	runtime->hw.channels_max = 0;
  	runtime->hw.rates = 0;
  	ptmin = UINT_MAX;
  	/* check min/max rates and channels */
  	list_for_each(p, &subs->fmt_list) {
  		struct audioformat *fp;
  		fp = list_entry(p, struct audioformat, list);
  		runtime->hw.rates |= fp->rates;
  		if (runtime->hw.rate_min > fp->rate_min)
  			runtime->hw.rate_min = fp->rate_min;
  		if (runtime->hw.rate_max < fp->rate_max)
  			runtime->hw.rate_max = fp->rate_max;
  		if (runtime->hw.channels_min > fp->channels)
  			runtime->hw.channels_min = fp->channels;
  		if (runtime->hw.channels_max < fp->channels)
  			runtime->hw.channels_max = fp->channels;
  		if (fp->fmt_type == UAC_FORMAT_TYPE_II && fp->frame_size > 0) {
  			/* FIXME: there might be more than one audio formats... */
  			runtime->hw.period_bytes_min = runtime->hw.period_bytes_max =
  				fp->frame_size;
  		}
  		pt = 125 * (1 << fp->datainterval);
  		ptmin = min(ptmin, pt);
  	}

  	err = snd_usb_autoresume(subs->stream->chip);
  	if (err < 0)
  		return err;

  
  	param_period_time_if_needed = SNDRV_PCM_HW_PARAM_PERIOD_TIME;

  	if (snd_usb_get_speed(subs->dev) == USB_SPEED_FULL)

  		/* full speed devices have fixed data packet interval */
  		ptmin = 1000;
  	if (ptmin == 1000)
  		/* if period time doesn't go below 1 ms, no rules needed */
  		param_period_time_if_needed = -1;
  	snd_pcm_hw_constraint_minmax(runtime, SNDRV_PCM_HW_PARAM_PERIOD_TIME,
  				     ptmin, UINT_MAX);
  
  	if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
  				       hw_rule_rate, subs,
  				       SNDRV_PCM_HW_PARAM_FORMAT,
  				       SNDRV_PCM_HW_PARAM_CHANNELS,
  				       param_period_time_if_needed,
  				       -1)) < 0)

  		goto rep_err;

  	if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
  				       hw_rule_channels, subs,
  				       SNDRV_PCM_HW_PARAM_FORMAT,
  				       SNDRV_PCM_HW_PARAM_RATE,
  				       param_period_time_if_needed,
  				       -1)) < 0)

  		goto rep_err;

  	if ((err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_FORMAT,
  				       hw_rule_format, subs,
  				       SNDRV_PCM_HW_PARAM_RATE,
  				       SNDRV_PCM_HW_PARAM_CHANNELS,
  				       param_period_time_if_needed,
  				       -1)) < 0)

  		goto rep_err;

  	if (param_period_time_if_needed >= 0) {
  		err = snd_pcm_hw_rule_add(runtime, 0,
  					  SNDRV_PCM_HW_PARAM_PERIOD_TIME,
  					  hw_rule_period_time, subs,
  					  SNDRV_PCM_HW_PARAM_FORMAT,
  					  SNDRV_PCM_HW_PARAM_CHANNELS,
  					  SNDRV_PCM_HW_PARAM_RATE,
  					  -1);
  		if (err < 0)

  			goto rep_err;

  	}
  	if ((err = snd_usb_pcm_check_knot(runtime, subs)) < 0)

  		goto rep_err;

  	return 0;

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

  }
  
  static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
  {
  	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct snd_usb_substream *subs = &as->substream[direction];
  
  	subs->interface = -1;

  	subs->altset_idx = 0;

  	runtime->hw = snd_usb_hardware;
  	runtime->private_data = subs;
  	subs->pcm_substream = substream;

  	/* runtime PM is also done there */

  	return setup_hw_info(runtime, subs);
  }
  
  static int snd_usb_pcm_close(struct snd_pcm_substream *substream, int direction)
  {
  	struct snd_usb_stream *as = snd_pcm_substream_chip(substream);
  	struct snd_usb_substream *subs = &as->substream[direction];
  
  	if (!as->chip->shutdown && subs->interface >= 0) {
  		usb_set_interface(subs->dev, subs->interface, 0);
  		subs->interface = -1;
  	}
  	subs->pcm_substream = NULL;

  	snd_usb_autosuspend(subs->stream->chip);

  	return 0;
  }
  
  static int snd_usb_playback_open(struct snd_pcm_substream *substream)
  {
  	return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_PLAYBACK);
  }
  
  static int snd_usb_playback_close(struct snd_pcm_substream *substream)
  {
  	return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_PLAYBACK);
  }
  
  static int snd_usb_capture_open(struct snd_pcm_substream *substream)
  {
  	return snd_usb_pcm_open(substream, SNDRV_PCM_STREAM_CAPTURE);
  }
  
  static int snd_usb_capture_close(struct snd_pcm_substream *substream)
  {
  	return snd_usb_pcm_close(substream, SNDRV_PCM_STREAM_CAPTURE);
  }
  
  static struct snd_pcm_ops snd_usb_playback_ops = {
  	.open =		snd_usb_playback_open,
  	.close =	snd_usb_playback_close,
  	.ioctl =	snd_pcm_lib_ioctl,
  	.hw_params =	snd_usb_hw_params,
  	.hw_free =	snd_usb_hw_free,
  	.prepare =	snd_usb_pcm_prepare,
  	.trigger =	snd_usb_substream_playback_trigger,
  	.pointer =	snd_usb_pcm_pointer,
  	.page =		snd_pcm_lib_get_vmalloc_page,
  	.mmap =		snd_pcm_lib_mmap_vmalloc,
  };
  
  static struct snd_pcm_ops snd_usb_capture_ops = {
  	.open =		snd_usb_capture_open,
  	.close =	snd_usb_capture_close,
  	.ioctl =	snd_pcm_lib_ioctl,
  	.hw_params =	snd_usb_hw_params,
  	.hw_free =	snd_usb_hw_free,
  	.prepare =	snd_usb_pcm_prepare,
  	.trigger =	snd_usb_substream_capture_trigger,
  	.pointer =	snd_usb_pcm_pointer,
  	.page =		snd_pcm_lib_get_vmalloc_page,
  	.mmap =		snd_pcm_lib_mmap_vmalloc,
  };
  
  void snd_usb_set_pcm_ops(struct snd_pcm *pcm, int stream)
  {
  	snd_pcm_set_ops(pcm, stream,
  			stream == SNDRV_PCM_STREAM_PLAYBACK ?
  			&snd_usb_playback_ops : &snd_usb_capture_ops);
  }