/*
   *   Clock domain and sample rate management functions
   *
   *   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/bitops.h>
  #include <linux/init.h>

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

  #include <linux/usb/audio.h>
  #include <linux/usb/audio-v2.h>
  
  #include <sound/core.h>
  #include <sound/info.h>
  #include <sound/pcm.h>

  
  #include "usbaudio.h"
  #include "card.h"

  #include "helper.h"

  #include "clock.h"

  
  static struct uac_clock_source_descriptor *
  	snd_usb_find_clock_source(struct usb_host_interface *ctrl_iface,
  				  int clock_id)
  {
  	struct uac_clock_source_descriptor *cs = NULL;
  
  	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
  					     ctrl_iface->extralen,
  					     cs, UAC2_CLOCK_SOURCE))) {
  		if (cs->bClockID == clock_id)
  			return cs;
  	}
  
  	return NULL;
  }
  
  static struct uac_clock_selector_descriptor *
  	snd_usb_find_clock_selector(struct usb_host_interface *ctrl_iface,
  				    int clock_id)
  {
  	struct uac_clock_selector_descriptor *cs = NULL;
  
  	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
  					     ctrl_iface->extralen,
  					     cs, UAC2_CLOCK_SELECTOR))) {
  		if (cs->bClockID == clock_id)
  			return cs;
  	}
  
  	return NULL;
  }
  
  static struct uac_clock_multiplier_descriptor *
  	snd_usb_find_clock_multiplier(struct usb_host_interface *ctrl_iface,
  				      int clock_id)
  {
  	struct uac_clock_multiplier_descriptor *cs = NULL;
  
  	while ((cs = snd_usb_find_csint_desc(ctrl_iface->extra,
  					     ctrl_iface->extralen,
  					     cs, UAC2_CLOCK_MULTIPLIER))) {
  		if (cs->bClockID == clock_id)
  			return cs;
  	}
  
  	return NULL;
  }
  
  static int uac_clock_selector_get_val(struct snd_usb_audio *chip, int selector_id)
  {
  	unsigned char buf;
  	int ret;
  
  	ret = snd_usb_ctl_msg(chip->dev, usb_rcvctrlpipe(chip->dev, 0),
  			      UAC2_CS_CUR,
  			      USB_RECIP_INTERFACE | USB_TYPE_CLASS | USB_DIR_IN,

  			      UAC2_CX_CLOCK_SELECTOR << 8,
  			      snd_usb_ctrl_intf(chip) | (selector_id << 8),

  			      &buf, sizeof(buf));

  
  	if (ret < 0)
  		return ret;
  
  	return buf;
  }
  
  static bool uac_clock_source_is_valid(struct snd_usb_audio *chip, int source_id)
  {
  	int err;
  	unsigned char data;
  	struct usb_device *dev = chip->dev;

  	struct uac_clock_source_descriptor *cs_desc =
  		snd_usb_find_clock_source(chip->ctrl_intf, source_id);
  
  	if (!cs_desc)
  		return 0;
  
  	/* If a clock source can't tell us whether it's valid, we assume it is */
  	if (!uac2_control_is_readable(cs_desc->bmControls, UAC2_CS_CONTROL_CLOCK_VALID))
  		return 1;

  
  	err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
  			      USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,

  			      UAC2_CS_CONTROL_CLOCK_VALID << 8,
  			      snd_usb_ctrl_intf(chip) | (source_id << 8),

  			      &data, sizeof(data));

  
  	if (err < 0) {
  		snd_printk(KERN_WARNING "%s(): cannot get clock validity for id %d
  ",
  			   __func__, source_id);

  		return 0;

  	}
  
  	return !!data;
  }

  static int __uac_clock_find_source(struct snd_usb_audio *chip,

  				   int entity_id, unsigned long *visited)
  {
  	struct uac_clock_source_descriptor *source;
  	struct uac_clock_selector_descriptor *selector;
  	struct uac_clock_multiplier_descriptor *multiplier;
  
  	entity_id &= 0xff;
  
  	if (test_and_set_bit(entity_id, visited)) {
  		snd_printk(KERN_WARNING
  			"%s(): recursive clock topology detected, id %d.
  ",
  			__func__, entity_id);
  		return -EINVAL;
  	}
  
  	/* first, see if the ID we're looking for is a clock source already */

  	source = snd_usb_find_clock_source(chip->ctrl_intf, entity_id);

  	if (source)
  		return source->bClockID;

  	selector = snd_usb_find_clock_selector(chip->ctrl_intf, entity_id);

  	if (selector) {
  		int ret;
  
  		/* the entity ID we are looking for is a selector.
  		 * find out what it currently selects */
  		ret = uac_clock_selector_get_val(chip, selector->bClockID);
  		if (ret < 0)
  			return ret;

  		/* Selector values are one-based */

  		if (ret > selector->bNrInPins || ret < 1) {
  			printk(KERN_ERR
  				"%s(): selector reported illegal value, id %d, ret %d
  ",
  				__func__, selector->bClockID, ret);
  
  			return -EINVAL;
  		}

  		return __uac_clock_find_source(chip, selector->baCSourceID[ret-1],

  					       visited);
  	}
  
  	/* FIXME: multipliers only act as pass-thru element for now */

  	multiplier = snd_usb_find_clock_multiplier(chip->ctrl_intf, entity_id);

  	if (multiplier)

  		return __uac_clock_find_source(chip, multiplier->bCSourceID,
  						visited);

  
  	return -EINVAL;
  }

  /*
   * For all kinds of sample rate settings and other device queries,
   * the clock source (end-leaf) must be used. However, clock selectors,
   * clock multipliers and sample rate converters may be specified as
   * clock source input to terminal. This functions walks the clock path
   * to its end and tries to find the source.
   *
   * The 'visited' bitfield is used internally to detect recursive loops.
   *
   * Returns the clock source UnitID (>=0) on success, or an error.
   */

  int snd_usb_clock_find_source(struct snd_usb_audio *chip, int entity_id)

  {
  	DECLARE_BITMAP(visited, 256);
  	memset(visited, 0, sizeof(visited));

  	return __uac_clock_find_source(chip, entity_id, visited);

  }
  
  static int set_sample_rate_v1(struct snd_usb_audio *chip, int iface,
  			      struct usb_host_interface *alts,
  			      struct audioformat *fmt, int rate)
  {
  	struct usb_device *dev = chip->dev;
  	unsigned int ep;
  	unsigned char data[3];
  	int err, crate;
  
  	ep = get_endpoint(alts, 0)->bEndpointAddress;
  
  	/* if endpoint doesn't have sampling rate control, bail out */

  	if (!(fmt->attributes & UAC_EP_CS_ATTR_SAMPLE_RATE))

  		return 0;

  
  	data[0] = rate;
  	data[1] = rate >> 8;
  	data[2] = rate >> 16;
  	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_SAMPLE_RATE << 8, ep,

  				   data, sizeof(data))) < 0) {

  		snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d to ep %#x
  ",
  			   dev->devnum, iface, fmt->altsetting, rate, ep);
  		return err;
  	}
  
  	if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC_GET_CUR,
  				   USB_TYPE_CLASS | USB_RECIP_ENDPOINT | USB_DIR_IN,
  				   UAC_EP_CS_ATTR_SAMPLE_RATE << 8, ep,

  				   data, sizeof(data))) < 0) {

  		snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq at ep %#x
  ",
  			   dev->devnum, iface, fmt->altsetting, ep);
  		return 0; /* some devices don't support reading */
  	}
  
  	crate = data[0] | (data[1] << 8) | (data[2] << 16);
  	if (crate != rate) {
  		snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d
  ", crate, rate);
  		// runtime->rate = crate;
  	}
  
  	return 0;
  }
  
  static int set_sample_rate_v2(struct snd_usb_audio *chip, int iface,
  			      struct usb_host_interface *alts,
  			      struct audioformat *fmt, int rate)
  {
  	struct usb_device *dev = chip->dev;
  	unsigned char data[4];
  	int err, crate;

  	int clock = snd_usb_clock_find_source(chip, fmt->clock);

  
  	if (clock < 0)
  		return clock;
  
  	if (!uac_clock_source_is_valid(chip, clock)) {

  		/* TODO: should we try to find valid clock setups by ourself? */

  		snd_printk(KERN_ERR "%d:%d:%d: clock source %d is not valid, cannot use
  ",
  			   dev->devnum, iface, fmt->altsetting, clock);
  		return -ENXIO;
  	}
  
  	data[0] = rate;
  	data[1] = rate >> 8;
  	data[2] = rate >> 16;
  	data[3] = rate >> 24;
  	if ((err = snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0), UAC2_CS_CUR,
  				   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,

  				   UAC2_CS_CONTROL_SAM_FREQ << 8,
  				   snd_usb_ctrl_intf(chip) | (clock << 8),

  				   data, sizeof(data))) < 0) {

  		snd_printk(KERN_ERR "%d:%d:%d: cannot set freq %d (v2)
  ",
  			   dev->devnum, iface, fmt->altsetting, rate);
  		return err;
  	}
  
  	if ((err = snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0), UAC2_CS_CUR,
  				   USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,

  				   UAC2_CS_CONTROL_SAM_FREQ << 8,
  				   snd_usb_ctrl_intf(chip) | (clock << 8),

  				   data, sizeof(data))) < 0) {

  		snd_printk(KERN_WARNING "%d:%d:%d: cannot get freq (v2)
  ",
  			   dev->devnum, iface, fmt->altsetting);
  		return err;
  	}
  
  	crate = data[0] | (data[1] << 8) | (data[2] << 16) | (data[3] << 24);
  	if (crate != rate)
  		snd_printd(KERN_WARNING "current rate %d is different from the runtime rate %d
  ", crate, rate);
  
  	return 0;
  }
  
  int snd_usb_init_sample_rate(struct snd_usb_audio *chip, int iface,
  			     struct usb_host_interface *alts,
  			     struct audioformat *fmt, int rate)
  {
  	struct usb_interface_descriptor *altsd = get_iface_desc(alts);
  
  	switch (altsd->bInterfaceProtocol) {
  	case UAC_VERSION_1:

  	default:

  		return set_sample_rate_v1(chip, iface, alts, fmt, rate);
  
  	case UAC_VERSION_2:
  		return set_sample_rate_v2(chip, iface, alts, fmt, rate);
  	}

  }