/*
   * Driver for Digigram VX soundcards
   *
   * PCM part
   *
   * Copyright (c) 2002,2003 by Takashi Iwai <tiwai@suse.de>
   *
   *   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
   *
   *
   * STRATEGY
   *  for playback, we send series of "chunks", which size is equal with the
   *  IBL size, typically 126 samples.  at each end of chunk, the end-of-buffer
   *  interrupt is notified, and the interrupt handler will feed the next chunk.
   *
   *  the current position is calculated from the sample count RMH.
   *  pipe->transferred is the counter of data which has been already transferred.
   *  if this counter reaches to the period size, snd_pcm_period_elapsed() will
   *  be issued.
   *
   *  for capture, the situation is much easier.
   *  to get a low latency response, we'll check the capture streams at each
   *  interrupt (capture stream has no EOB notification).  if the pending
   *  data is accumulated to the period size, snd_pcm_period_elapsed() is
   *  called and the pointer is updated.
   *
   *  the current point of read buffer is kept in pipe->hw_ptr.  note that
   *  this is in bytes.
   *
   *
   * TODO
   *  - linked trigger for full-duplex mode.
   *  - scheduled action on the stream.
   */
  
  #include <linux/slab.h>
  #include <linux/delay.h>
  #include <sound/core.h>
  #include <sound/asoundef.h>
  #include <sound/pcm.h>
  #include <sound/vx_core.h>
  #include "vx_cmd.h"
  
  
  /*
   * read three pending pcm bytes via inb()
   */
  static void vx_pcm_read_per_bytes(struct vx_core *chip, struct snd_pcm_runtime *runtime,
  				  struct vx_pipe *pipe)
  {
  	int offset = pipe->hw_ptr;
  	unsigned char *buf = (unsigned char *)(runtime->dma_area + offset);
  	*buf++ = vx_inb(chip, RXH);
  	if (++offset >= pipe->buffer_bytes) {
  		offset = 0;
  		buf = (unsigned char *)runtime->dma_area;
  	}
  	*buf++ = vx_inb(chip, RXM);
  	if (++offset >= pipe->buffer_bytes) {
  		offset = 0;
  		buf = (unsigned char *)runtime->dma_area;
  	}
  	*buf++ = vx_inb(chip, RXL);
  	if (++offset >= pipe->buffer_bytes) {
  		offset = 0;
  		buf = (unsigned char *)runtime->dma_area;
  	}
  	pipe->hw_ptr = offset;
  }
  
  /*
   * vx_set_pcx_time - convert from the PC time to the RMH status time.
   * @pc_time: the pointer for the PC-time to set
   * @dsp_time: the pointer for RMH status time array
   */
  static void vx_set_pcx_time(struct vx_core *chip, pcx_time_t *pc_time,
  			    unsigned int *dsp_time)
  {
  	dsp_time[0] = (unsigned int)((*pc_time) >> 24) & PCX_TIME_HI_MASK;
  	dsp_time[1] = (unsigned int)(*pc_time) &  MASK_DSP_WORD;
  }
  
  /*
   * vx_set_differed_time - set the differed time if specified
   * @rmh: the rmh record to modify
   * @pipe: the pipe to be checked
   *
   * if the pipe is programmed with the differed time, set the DSP time
   * on the rmh and changes its command length.
   *
   * returns the increase of the command length.
   */
  static int vx_set_differed_time(struct vx_core *chip, struct vx_rmh *rmh,
  				struct vx_pipe *pipe)
  {
  	/* Update The length added to the RMH command by the timestamp */
  	if (! (pipe->differed_type & DC_DIFFERED_DELAY))
  		return 0;
  		
  	/* Set the T bit */
  	rmh->Cmd[0] |= DSP_DIFFERED_COMMAND_MASK;
  
  	/* Time stamp is the 1st following parameter */
  	vx_set_pcx_time(chip, &pipe->pcx_time, &rmh->Cmd[1]);
  
  	/* Add the flags to a notified differed command */
  	if (pipe->differed_type & DC_NOTIFY_DELAY)
  		rmh->Cmd[1] |= NOTIFY_MASK_TIME_HIGH ;
  
  	/* Add the flags to a multiple differed command */
  	if (pipe->differed_type & DC_MULTIPLE_DELAY)
  		rmh->Cmd[1] |= MULTIPLE_MASK_TIME_HIGH;
  
  	/* Add the flags to a stream-time differed command */
  	if (pipe->differed_type & DC_STREAM_TIME_DELAY)
  		rmh->Cmd[1] |= STREAM_MASK_TIME_HIGH;
  		
  	rmh->LgCmd += 2;
  	return 2;
  }
  
  /*
   * vx_set_stream_format - send the stream format command
   * @pipe: the affected pipe
   * @data: format bitmask
   */
  static int vx_set_stream_format(struct vx_core *chip, struct vx_pipe *pipe,
  				unsigned int data)
  {
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, pipe->is_capture ?
  		    CMD_FORMAT_STREAM_IN : CMD_FORMAT_STREAM_OUT);
  	rmh.Cmd[0] |= pipe->number << FIELD_SIZE;
  
          /* Command might be longer since we may have to add a timestamp */
  	vx_set_differed_time(chip, &rmh, pipe);
  
  	rmh.Cmd[rmh.LgCmd] = (data & 0xFFFFFF00) >> 8;
  	rmh.Cmd[rmh.LgCmd + 1] = (data & 0xFF) << 16 /*| (datal & 0xFFFF00) >> 8*/;
  	rmh.LgCmd += 2;
      
  	return vx_send_msg(chip, &rmh);
  }
  
  
  /*
   * vx_set_format - set the format of a pipe
   * @pipe: the affected pipe
   * @runtime: pcm runtime instance to be referred
   *
   * returns 0 if successful, or a negative error code.
   */
  static int vx_set_format(struct vx_core *chip, struct vx_pipe *pipe,
  			 struct snd_pcm_runtime *runtime)
  {
  	unsigned int header = HEADER_FMT_BASE;
  
  	if (runtime->channels == 1)
  		header |= HEADER_FMT_MONO;
  	if (snd_pcm_format_little_endian(runtime->format))
  		header |= HEADER_FMT_INTEL;
  	if (runtime->rate < 32000 && runtime->rate > 11025)
  		header |= HEADER_FMT_UPTO32;
  	else if (runtime->rate <= 11025)
  		header |= HEADER_FMT_UPTO11;
  
  	switch (snd_pcm_format_physical_width(runtime->format)) {
  	// case 8: break;
  	case 16: header |= HEADER_FMT_16BITS; break;
  	case 24: header |= HEADER_FMT_24BITS; break;
  	default : 
  		snd_BUG();
  		return -EINVAL;
  	}
  
  	return vx_set_stream_format(chip, pipe, header);
  }
  
  /*
   * set / query the IBL size
   */
  static int vx_set_ibl(struct vx_core *chip, struct vx_ibl_info *info)
  {
  	int err;
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, CMD_IBL);
  	rmh.Cmd[0] |= info->size & 0x03ffff;
  	err = vx_send_msg(chip, &rmh);
  	if (err < 0)
  		return err;
  	info->size = rmh.Stat[0];
  	info->max_size = rmh.Stat[1];
  	info->min_size = rmh.Stat[2];
  	info->granularity = rmh.Stat[3];
  	snd_printdd(KERN_DEBUG "vx_set_ibl: size = %d, max = %d, min = %d, gran = %d
  ",
  		   info->size, info->max_size, info->min_size, info->granularity);
  	return 0;
  }
  
  
  /*
   * vx_get_pipe_state - get the state of a pipe
   * @pipe: the pipe to be checked
   * @state: the pointer for the returned state
   *
   * checks the state of a given pipe, and stores the state (1 = running,
   * 0 = paused) on the given pointer.
   *
   * called from trigger callback only
   */
  static int vx_get_pipe_state(struct vx_core *chip, struct vx_pipe *pipe, int *state)
  {
  	int err;
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, CMD_PIPE_STATE);
  	vx_set_pipe_cmd_params(&rmh, pipe->is_capture, pipe->number, 0);
  	err = vx_send_msg(chip, &rmh);
  	if (! err)
  		*state = (rmh.Stat[0] & (1 << pipe->number)) ? 1 : 0;
  	return err;
  }
  
  
  /*
   * vx_query_hbuffer_size - query available h-buffer size in bytes
   * @pipe: the pipe to be checked
   *
   * return the available size on h-buffer in bytes,
   * or a negative error code.
   *
   * NOTE: calling this function always switches to the stream mode.
   *       you'll need to disconnect the host to get back to the
   *       normal mode.
   */
  static int vx_query_hbuffer_size(struct vx_core *chip, struct vx_pipe *pipe)
  {
  	int result;
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, CMD_SIZE_HBUFFER);
  	vx_set_pipe_cmd_params(&rmh, pipe->is_capture, pipe->number, 0);
  	if (pipe->is_capture)
  		rmh.Cmd[0] |= 0x00000001;
  	result = vx_send_msg(chip, &rmh);
  	if (! result)
  		result = rmh.Stat[0] & 0xffff;
  	return result;
  }
  
  
  /*
   * vx_pipe_can_start - query whether a pipe is ready for start
   * @pipe: the pipe to be checked
   *
   * return 1 if ready, 0 if not ready, and negative value on error.
   *
   * called from trigger callback only
   */
  static int vx_pipe_can_start(struct vx_core *chip, struct vx_pipe *pipe)
  {
  	int err;
  	struct vx_rmh rmh;
          
  	vx_init_rmh(&rmh, CMD_CAN_START_PIPE);
  	vx_set_pipe_cmd_params(&rmh, pipe->is_capture, pipe->number, 0);
  	rmh.Cmd[0] |= 1;
  
  	err = vx_send_msg(chip, &rmh);
  	if (! err) {
  		if (rmh.Stat[0])
  			err = 1;
  	}
  	return err;
  }
  
  /*
   * vx_conf_pipe - tell the pipe to stand by and wait for IRQA.
   * @pipe: the pipe to be configured
   */
  static int vx_conf_pipe(struct vx_core *chip, struct vx_pipe *pipe)
  {
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, CMD_CONF_PIPE);
  	if (pipe->is_capture)
  		rmh.Cmd[0] |= COMMAND_RECORD_MASK;
  	rmh.Cmd[1] = 1 << pipe->number;
  	return vx_send_msg(chip, &rmh);
  }
  
  /*
   * vx_send_irqa - trigger IRQA
   */
  static int vx_send_irqa(struct vx_core *chip)
  {
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, CMD_SEND_IRQA);
  	return vx_send_msg(chip, &rmh);
  }
  
  
  #define MAX_WAIT_FOR_DSP        250
  /*
   * vx boards do not support inter-card sync, besides
   * only 126 samples require to be prepared before a pipe can start
   */
  #define CAN_START_DELAY         2	/* wait 2ms only before asking if the pipe is ready*/
  #define WAIT_STATE_DELAY        2	/* wait 2ms after irqA was requested and check if the pipe state toggled*/
  
  /*
   * vx_toggle_pipe - start / pause a pipe
   * @pipe: the pipe to be triggered
   * @state: start = 1, pause = 0
   *
   * called from trigger callback only
   *
   */
  static int vx_toggle_pipe(struct vx_core *chip, struct vx_pipe *pipe, int state)
  {
  	int err, i, cur_state;
  
  	/* Check the pipe is not already in the requested state */
  	if (vx_get_pipe_state(chip, pipe, &cur_state) < 0)
  		return -EBADFD;
  	if (state == cur_state)
  		return 0;
  
  	/* If a start is requested, ask the DSP to get prepared
  	 * and wait for a positive acknowledge (when there are
  	 * enough sound buffer for this pipe)
  	 */
  	if (state) {
  		for (i = 0 ; i < MAX_WAIT_FOR_DSP; i++) {
  			err = vx_pipe_can_start(chip, pipe);
  			if (err > 0)
  				break;
  			/* Wait for a few, before asking again
  			 * to avoid flooding the DSP with our requests
  			 */
  			mdelay(1);
  		}
  	}
      
  	if ((err = vx_conf_pipe(chip, pipe)) < 0)
  		return err;
  
  	if ((err = vx_send_irqa(chip)) < 0)
  		return err;
      
  	/* If it completes successfully, wait for the pipes
  	 * reaching the expected state before returning
  	 * Check one pipe only (since they are synchronous)
  	 */
  	for (i = 0; i < MAX_WAIT_FOR_DSP; i++) {
  		err = vx_get_pipe_state(chip, pipe, &cur_state);
  		if (err < 0 || cur_state == state)
  			break;
  		err = -EIO;
  		mdelay(1);
  	}
  	return err < 0 ? -EIO : 0;
  }
  
      
  /*
   * vx_stop_pipe - stop a pipe
   * @pipe: the pipe to be stopped
   *
   * called from trigger callback only
   */
  static int vx_stop_pipe(struct vx_core *chip, struct vx_pipe *pipe)
  {
  	struct vx_rmh rmh;
  	vx_init_rmh(&rmh, CMD_STOP_PIPE);
  	vx_set_pipe_cmd_params(&rmh, pipe->is_capture, pipe->number, 0);
  	return vx_send_msg(chip, &rmh);
  }
  
  
  /*
   * vx_alloc_pipe - allocate a pipe and initialize the pipe instance
   * @capture: 0 = playback, 1 = capture operation
   * @audioid: the audio id to be assigned
   * @num_audio: number of audio channels
   * @pipep: the returned pipe instance
   *
   * return 0 on success, or a negative error code.
   */
  static int vx_alloc_pipe(struct vx_core *chip, int capture,
  			 int audioid, int num_audio,
  			 struct vx_pipe **pipep)
  {
  	int err;
  	struct vx_pipe *pipe;
  	struct vx_rmh rmh;
  	int data_mode;
  
  	*pipep = NULL;
  	vx_init_rmh(&rmh, CMD_RES_PIPE);
  	vx_set_pipe_cmd_params(&rmh, capture, audioid, num_audio);
  #if 0	// NYI
  	if (underrun_skip_sound)
  		rmh.Cmd[0] |= BIT_SKIP_SOUND;
  #endif	// NYI
  	data_mode = (chip->uer_bits & IEC958_AES0_NONAUDIO) != 0;
  	if (! capture && data_mode)
  		rmh.Cmd[0] |= BIT_DATA_MODE;
  	err = vx_send_msg(chip, &rmh);
  	if (err < 0)
  		return err;
  
  	/* initialize the pipe record */
  	pipe = kzalloc(sizeof(*pipe), GFP_KERNEL);
  	if (! pipe) {
  		/* release the pipe */
  		vx_init_rmh(&rmh, CMD_FREE_PIPE);
  		vx_set_pipe_cmd_params(&rmh, capture, audioid, 0);
  		vx_send_msg(chip, &rmh);
  		return -ENOMEM;
  	}
  
  	/* the pipe index should be identical with the audio index */
  	pipe->number = audioid;
  	pipe->is_capture = capture;
  	pipe->channels = num_audio;
  	pipe->differed_type = 0;
  	pipe->pcx_time = 0;
  	pipe->data_mode = data_mode;
  	*pipep = pipe;
  
  	return 0;
  }
  
  
  /*
   * vx_free_pipe - release a pipe
   * @pipe: pipe to be released
   */
  static int vx_free_pipe(struct vx_core *chip, struct vx_pipe *pipe)
  {
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, CMD_FREE_PIPE);
  	vx_set_pipe_cmd_params(&rmh, pipe->is_capture, pipe->number, 0);
  	vx_send_msg(chip, &rmh);
  
  	kfree(pipe);
  	return 0;
  }
  
  
  /*
   * vx_start_stream - start the stream
   *
   * called from trigger callback only
   */
  static int vx_start_stream(struct vx_core *chip, struct vx_pipe *pipe)
  {
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, CMD_START_ONE_STREAM);
  	vx_set_stream_cmd_params(&rmh, pipe->is_capture, pipe->number);
  	vx_set_differed_time(chip, &rmh, pipe);
  	return vx_send_msg(chip, &rmh);
  }
  
  
  /*
   * vx_stop_stream - stop the stream
   *
   * called from trigger callback only
   */
  static int vx_stop_stream(struct vx_core *chip, struct vx_pipe *pipe)
  {
  	struct vx_rmh rmh;
  
  	vx_init_rmh(&rmh, CMD_STOP_STREAM);
  	vx_set_stream_cmd_params(&rmh, pipe->is_capture, pipe->number);
  	return vx_send_msg(chip, &rmh);
  }
  
  
  /*
   * playback hw information
   */
  
  static struct snd_pcm_hardware vx_pcm_playback_hw = {
  	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
  				 SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_MMAP_VALID /*|*/
  				 /*SNDRV_PCM_INFO_RESUME*/),
  	.formats =		(/*SNDRV_PCM_FMTBIT_U8 |*/
  				 SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_3LE),
  	.rates =		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
  	.rate_min =		5000,
  	.rate_max =		48000,
  	.channels_min =		1,
  	.channels_max =		2,
  	.buffer_bytes_max =	(128*1024),
  	.period_bytes_min =	126,
  	.period_bytes_max =	(128*1024),
  	.periods_min =		2,
  	.periods_max =		VX_MAX_PERIODS,
  	.fifo_size =		126,
  };
  
  
  /*
   * vx_pcm_playback_open - open callback for playback
   */
  static int vx_pcm_playback_open(struct snd_pcm_substream *subs)
  {
  	struct snd_pcm_runtime *runtime = subs->runtime;
  	struct vx_core *chip = snd_pcm_substream_chip(subs);
  	struct vx_pipe *pipe = NULL;
  	unsigned int audio;
  	int err;
  
  	if (chip->chip_status & VX_STAT_IS_STALE)
  		return -EBUSY;
  
  	audio = subs->pcm->device * 2;
  	if (snd_BUG_ON(audio >= chip->audio_outs))
  		return -EINVAL;
  	
  	/* playback pipe may have been already allocated for monitoring */
  	pipe = chip->playback_pipes[audio];
  	if (! pipe) {
  		/* not allocated yet */
  		err = vx_alloc_pipe(chip, 0, audio, 2, &pipe); /* stereo playback */
  		if (err < 0)
  			return err;
  		chip->playback_pipes[audio] = pipe;
  	}
  	/* open for playback */
  	pipe->references++;
  
  	pipe->substream = subs;
  	chip->playback_pipes[audio] = pipe;
  
  	runtime->hw = vx_pcm_playback_hw;
  	runtime->hw.period_bytes_min = chip->ibl.size;
  	runtime->private_data = pipe;
  
  	/* align to 4 bytes (otherwise will be problematic when 24bit is used) */ 
  	snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 4);
  	snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 4);
  
  	return 0;
  }
  
  /*
   * vx_pcm_playback_close - close callback for playback
   */
  static int vx_pcm_playback_close(struct snd_pcm_substream *subs)
  {
  	struct vx_core *chip = snd_pcm_substream_chip(subs);
  	struct vx_pipe *pipe;
  
  	if (! subs->runtime->private_data)
  		return -EINVAL;
  
  	pipe = subs->runtime->private_data;
  
  	if (--pipe->references == 0) {
  		chip->playback_pipes[pipe->number] = NULL;
  		vx_free_pipe(chip, pipe);
  	}
  
  	return 0;
  
  }
  
  
  /*
   * vx_notify_end_of_buffer - send "end-of-buffer" notifier at the given pipe
   * @pipe: the pipe to notify
   *
   * NB: call with a certain lock.
   */
  static int vx_notify_end_of_buffer(struct vx_core *chip, struct vx_pipe *pipe)
  {
  	int err;
  	struct vx_rmh rmh;  /* use a temporary rmh here */
  
  	/* Toggle Dsp Host Interface into Message mode */
  	vx_send_rih_nolock(chip, IRQ_PAUSE_START_CONNECT);
  	vx_init_rmh(&rmh, CMD_NOTIFY_END_OF_BUFFER);
  	vx_set_stream_cmd_params(&rmh, 0, pipe->number);
  	err = vx_send_msg_nolock(chip, &rmh);
  	if (err < 0)
  		return err;
  	/* Toggle Dsp Host Interface back to sound transfer mode */
  	vx_send_rih_nolock(chip, IRQ_PAUSE_START_CONNECT);
  	return 0;
  }
  
  /*
   * vx_pcm_playback_transfer_chunk - transfer a single chunk
   * @subs: substream
   * @pipe: the pipe to transfer
   * @size: chunk size in bytes
   *
   * transfer a single buffer chunk.  EOB notificaton is added after that.
   * called from the interrupt handler, too.
   *
   * return 0 if ok.
   */
  static int vx_pcm_playback_transfer_chunk(struct vx_core *chip,
  					  struct snd_pcm_runtime *runtime,
  					  struct vx_pipe *pipe, int size)
  {
  	int space, err = 0;
  
  	space = vx_query_hbuffer_size(chip, pipe);
  	if (space < 0) {
  		/* disconnect the host, SIZE_HBUF command always switches to the stream mode */
  		vx_send_rih(chip, IRQ_CONNECT_STREAM_NEXT);
  		snd_printd("error hbuffer
  ");
  		return space;
  	}
  	if (space < size) {
  		vx_send_rih(chip, IRQ_CONNECT_STREAM_NEXT);
  		snd_printd("no enough hbuffer space %d
  ", space);
  		return -EIO; /* XRUN */
  	}
  		
  	/* we don't need irqsave here, because this function
  	 * is called from either trigger callback or irq handler
  	 */
  	mutex_lock(&chip->lock);
  	vx_pseudo_dma_write(chip, runtime, pipe, size);
  	err = vx_notify_end_of_buffer(chip, pipe);
  	/* disconnect the host, SIZE_HBUF command always switches to the stream mode */
  	vx_send_rih_nolock(chip, IRQ_CONNECT_STREAM_NEXT);
  	mutex_unlock(&chip->lock);
  	return err;
  }
  
  /*
   * update the position of the given pipe.
   * pipe->position is updated and wrapped within the buffer size.
   * pipe->transferred is updated, too, but the size is not wrapped,
   * so that the caller can check the total transferred size later
   * (to call snd_pcm_period_elapsed).
   */
  static int vx_update_pipe_position(struct vx_core *chip,
  				   struct snd_pcm_runtime *runtime,
  				   struct vx_pipe *pipe)
  {
  	struct vx_rmh rmh;
  	int err, update;
  	u64 count;
  
  	vx_init_rmh(&rmh, CMD_STREAM_SAMPLE_COUNT);
  	vx_set_pipe_cmd_params(&rmh, pipe->is_capture, pipe->number, 0);
  	err = vx_send_msg(chip, &rmh);
  	if (err < 0)
  		return err;
  
  	count = ((u64)(rmh.Stat[0] & 0xfffff) << 24) | (u64)rmh.Stat[1];
  	update = (int)(count - pipe->cur_count);
  	pipe->cur_count = count;
  	pipe->position += update;
  	if (pipe->position >= (int)runtime->buffer_size)
  		pipe->position %= runtime->buffer_size;
  	pipe->transferred += update;
  	return 0;
  }
  
  /*
   * transfer the pending playback buffer data to DSP
   * called from interrupt handler
   */
  static void vx_pcm_playback_transfer(struct vx_core *chip,
  				     struct snd_pcm_substream *subs,
  				     struct vx_pipe *pipe, int nchunks)
  {
  	int i, err;
  	struct snd_pcm_runtime *runtime = subs->runtime;
  
  	if (! pipe->prepared || (chip->chip_status & VX_STAT_IS_STALE))
  		return;
  	for (i = 0; i < nchunks; i++) {
  		if ((err = vx_pcm_playback_transfer_chunk(chip, runtime, pipe,
  							  chip->ibl.size)) < 0)
  			return;
  	}
  }
  
  /*
   * update the playback position and call snd_pcm_period_elapsed() if necessary
   * called from interrupt handler
   */
  static void vx_pcm_playback_update(struct vx_core *chip,
  				   struct snd_pcm_substream *subs,
  				   struct vx_pipe *pipe)
  {
  	int err;
  	struct snd_pcm_runtime *runtime = subs->runtime;
  
  	if (pipe->running && ! (chip->chip_status & VX_STAT_IS_STALE)) {
  		if ((err = vx_update_pipe_position(chip, runtime, pipe)) < 0)
  			return;
  		if (pipe->transferred >= (int)runtime->period_size) {
  			pipe->transferred %= runtime->period_size;
  			snd_pcm_period_elapsed(subs);
  		}
  	}
  }
  
  /*
   * vx_pcm_playback_trigger - trigger callback for playback
   */
  static int vx_pcm_trigger(struct snd_pcm_substream *subs, int cmd)
  {
  	struct vx_core *chip = snd_pcm_substream_chip(subs);
  	struct vx_pipe *pipe = subs->runtime->private_data;
  	int err;
  
  	if (chip->chip_status & VX_STAT_IS_STALE)
  		return -EBUSY;
  		
  	switch (cmd) {
  	case SNDRV_PCM_TRIGGER_START:
  	case SNDRV_PCM_TRIGGER_RESUME:
  		if (! pipe->is_capture)
  			vx_pcm_playback_transfer(chip, subs, pipe, 2);
  		err = vx_start_stream(chip, pipe);
  		if (err < 0) {
  			pr_debug("vx: cannot start stream
  ");
  			return err;
  		}
  		err = vx_toggle_pipe(chip, pipe, 1);
  		if (err < 0) {
  			pr_debug("vx: cannot start pipe
  ");
  			vx_stop_stream(chip, pipe);
  			return err;
  		}
  		chip->pcm_running++;
  		pipe->running = 1;
  		break;
  	case SNDRV_PCM_TRIGGER_STOP:
  	case SNDRV_PCM_TRIGGER_SUSPEND:
  		vx_toggle_pipe(chip, pipe, 0);
  		vx_stop_pipe(chip, pipe);
  		vx_stop_stream(chip, pipe);
  		chip->pcm_running--;
  		pipe->running = 0;
  		break;
  	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
  		if ((err = vx_toggle_pipe(chip, pipe, 0)) < 0)
  			return err;
  		break;
  	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
  		if ((err = vx_toggle_pipe(chip, pipe, 1)) < 0)
  			return err;
  		break;
  	default:
  		return -EINVAL;
  	}
  	return 0;
  }
  
  /*
   * vx_pcm_playback_pointer - pointer callback for playback
   */
  static snd_pcm_uframes_t vx_pcm_playback_pointer(struct snd_pcm_substream *subs)
  {
  	struct snd_pcm_runtime *runtime = subs->runtime;
  	struct vx_pipe *pipe = runtime->private_data;
  	return pipe->position;
  }
  
  /*
   * vx_pcm_hw_params - hw_params callback for playback and capture
   */
  static int vx_pcm_hw_params(struct snd_pcm_substream *subs,
  				     struct snd_pcm_hw_params *hw_params)
  {
  	return snd_pcm_lib_alloc_vmalloc_32_buffer
  					(subs, params_buffer_bytes(hw_params));
  }
  
  /*
   * vx_pcm_hw_free - hw_free callback for playback and capture
   */
  static int vx_pcm_hw_free(struct snd_pcm_substream *subs)
  {
  	return snd_pcm_lib_free_vmalloc_buffer(subs);
  }
  
  /*
   * vx_pcm_prepare - prepare callback for playback and capture
   */
  static int vx_pcm_prepare(struct snd_pcm_substream *subs)
  {
  	struct vx_core *chip = snd_pcm_substream_chip(subs);
  	struct snd_pcm_runtime *runtime = subs->runtime;
  	struct vx_pipe *pipe = runtime->private_data;
  	int err, data_mode;
  	// int max_size, nchunks;
  
  	if (chip->chip_status & VX_STAT_IS_STALE)
  		return -EBUSY;
  
  	data_mode = (chip->uer_bits & IEC958_AES0_NONAUDIO) != 0;
  	if (data_mode != pipe->data_mode && ! pipe->is_capture) {
  		/* IEC958 status (raw-mode) was changed */
  		/* we reopen the pipe */
  		struct vx_rmh rmh;
  		snd_printdd(KERN_DEBUG "reopen the pipe with data_mode = %d
  ", data_mode);
  		vx_init_rmh(&rmh, CMD_FREE_PIPE);
  		vx_set_pipe_cmd_params(&rmh, 0, pipe->number, 0);
  		if ((err = vx_send_msg(chip, &rmh)) < 0)
  			return err;
  		vx_init_rmh(&rmh, CMD_RES_PIPE);
  		vx_set_pipe_cmd_params(&rmh, 0, pipe->number, pipe->channels);
  		if (data_mode)
  			rmh.Cmd[0] |= BIT_DATA_MODE;
  		if ((err = vx_send_msg(chip, &rmh)) < 0)
  			return err;
  		pipe->data_mode = data_mode;
  	}
  
  	if (chip->pcm_running && chip->freq != runtime->rate) {
  		snd_printk(KERN_ERR "vx: cannot set different clock %d "
  			   "from the current %d
  ", runtime->rate, chip->freq);
  		return -EINVAL;
  	}
  	vx_set_clock(chip, runtime->rate);
  
  	if ((err = vx_set_format(chip, pipe, runtime)) < 0)
  		return err;
  
  	if (vx_is_pcmcia(chip)) {
  		pipe->align = 2; /* 16bit word */
  	} else {
  		pipe->align = 4; /* 32bit word */
  	}
  
  	pipe->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
  	pipe->period_bytes = frames_to_bytes(runtime, runtime->period_size);
  	pipe->hw_ptr = 0;
  
  	/* set the timestamp */
  	vx_update_pipe_position(chip, runtime, pipe);
  	/* clear again */
  	pipe->transferred = 0;
  	pipe->position = 0;
  
  	pipe->prepared = 1;
  
  	return 0;
  }
  
  
  /*
   * operators for PCM playback
   */
  static struct snd_pcm_ops vx_pcm_playback_ops = {
  	.open =		vx_pcm_playback_open,
  	.close =	vx_pcm_playback_close,
  	.ioctl =	snd_pcm_lib_ioctl,
  	.hw_params =	vx_pcm_hw_params,
  	.hw_free =	vx_pcm_hw_free,
  	.prepare =	vx_pcm_prepare,
  	.trigger =	vx_pcm_trigger,
  	.pointer =	vx_pcm_playback_pointer,
  	.page =		snd_pcm_lib_get_vmalloc_page,
  	.mmap =		snd_pcm_lib_mmap_vmalloc,
  };
  
  
  /*
   * playback hw information
   */
  
  static struct snd_pcm_hardware vx_pcm_capture_hw = {
  	.info =			(SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
  				 SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_MMAP_VALID /*|*/
  				 /*SNDRV_PCM_INFO_RESUME*/),
  	.formats =		(/*SNDRV_PCM_FMTBIT_U8 |*/
  				 SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_3LE),
  	.rates =		SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
  	.rate_min =		5000,
  	.rate_max =		48000,
  	.channels_min =		1,
  	.channels_max =		2,
  	.buffer_bytes_max =	(128*1024),
  	.period_bytes_min =	126,
  	.period_bytes_max =	(128*1024),
  	.periods_min =		2,
  	.periods_max =		VX_MAX_PERIODS,
  	.fifo_size =		126,
  };
  
  
  /*
   * vx_pcm_capture_open - open callback for capture
   */
  static int vx_pcm_capture_open(struct snd_pcm_substream *subs)
  {
  	struct snd_pcm_runtime *runtime = subs->runtime;
  	struct vx_core *chip = snd_pcm_substream_chip(subs);
  	struct vx_pipe *pipe;
  	struct vx_pipe *pipe_out_monitoring = NULL;
  	unsigned int audio;
  	int err;
  
  	if (chip->chip_status & VX_STAT_IS_STALE)
  		return -EBUSY;
  
  	audio = subs->pcm->device * 2;
  	if (snd_BUG_ON(audio >= chip->audio_ins))
  		return -EINVAL;
  	err = vx_alloc_pipe(chip, 1, audio, 2, &pipe);
  	if (err < 0)
  		return err;
  	pipe->substream = subs;
  	chip->capture_pipes[audio] = pipe;
  
  	/* check if monitoring is needed */
  	if (chip->audio_monitor_active[audio]) {
  		pipe_out_monitoring = chip->playback_pipes[audio];
  		if (! pipe_out_monitoring) {
  			/* allocate a pipe */
  			err = vx_alloc_pipe(chip, 0, audio, 2, &pipe_out_monitoring);
  			if (err < 0)
  				return err;
  			chip->playback_pipes[audio] = pipe_out_monitoring;
  		}
  		pipe_out_monitoring->references++;
  		/* 
  		   if an output pipe is available, it's audios still may need to be 
  		   unmuted. hence we'll have to call a mixer entry point.
  		*/
  		vx_set_monitor_level(chip, audio, chip->audio_monitor[audio],
  				     chip->audio_monitor_active[audio]);
  		/* assuming stereo */
  		vx_set_monitor_level(chip, audio+1, chip->audio_monitor[audio+1],
  				     chip->audio_monitor_active[audio+1]); 
  	}
  
  	pipe->monitoring_pipe = pipe_out_monitoring; /* default value NULL */
  
  	runtime->hw = vx_pcm_capture_hw;
  	runtime->hw.period_bytes_min = chip->ibl.size;
  	runtime->private_data = pipe;
  
  	/* align to 4 bytes (otherwise will be problematic when 24bit is used) */ 
  	snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 4);
  	snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 4);
  
  	return 0;
  }
  
  /*
   * vx_pcm_capture_close - close callback for capture
   */
  static int vx_pcm_capture_close(struct snd_pcm_substream *subs)
  {
  	struct vx_core *chip = snd_pcm_substream_chip(subs);
  	struct vx_pipe *pipe;
  	struct vx_pipe *pipe_out_monitoring;
  	
  	if (! subs->runtime->private_data)
  		return -EINVAL;
  	pipe = subs->runtime->private_data;
  	chip->capture_pipes[pipe->number] = NULL;
  
  	pipe_out_monitoring = pipe->monitoring_pipe;
  
  	/*
  	  if an output pipe is attached to this input, 
  	  check if it needs to be released.
  	*/
  	if (pipe_out_monitoring) {
  		if (--pipe_out_monitoring->references == 0) {
  			vx_free_pipe(chip, pipe_out_monitoring);
  			chip->playback_pipes[pipe->number] = NULL;
  			pipe->monitoring_pipe = NULL;
  		}
  	}
  	
  	vx_free_pipe(chip, pipe);
  	return 0;
  }
  
  
  
  #define DMA_READ_ALIGN	6	/* hardware alignment for read */
  
  /*
   * vx_pcm_capture_update - update the capture buffer
   */
  static void vx_pcm_capture_update(struct vx_core *chip, struct snd_pcm_substream *subs,
  				  struct vx_pipe *pipe)
  {
  	int size, space, count;
  	struct snd_pcm_runtime *runtime = subs->runtime;
  
  	if (! pipe->prepared || (chip->chip_status & VX_STAT_IS_STALE))
  		return;
  
  	size = runtime->buffer_size - snd_pcm_capture_avail(runtime);
  	if (! size)
  		return;
  	size = frames_to_bytes(runtime, size);
  	space = vx_query_hbuffer_size(chip, pipe);
  	if (space < 0)
  		goto _error;
  	if (size > space)
  		size = space;
  	size = (size / 3) * 3; /* align to 3 bytes */
  	if (size < DMA_READ_ALIGN)
  		goto _error;
  
  	/* keep the last 6 bytes, they will be read after disconnection */
  	count = size - DMA_READ_ALIGN;
  	/* read bytes until the current pointer reaches to the aligned position
  	 * for word-transfer
  	 */
  	while (count > 0) {
  		if ((pipe->hw_ptr % pipe->align) == 0)
  			break;
  		if (vx_wait_for_rx_full(chip) < 0)
  			goto _error;
  		vx_pcm_read_per_bytes(chip, runtime, pipe);
  		count -= 3;
  	}
  	if (count > 0) {
  		/* ok, let's accelerate! */
  		int align = pipe->align * 3;
  		space = (count / align) * align;
  		vx_pseudo_dma_read(chip, runtime, pipe, space);
  		count -= space;
  	}
  	/* read the rest of bytes */
  	while (count > 0) {
  		if (vx_wait_for_rx_full(chip) < 0)
  			goto _error;
  		vx_pcm_read_per_bytes(chip, runtime, pipe);
  		count -= 3;
  	}
  	/* disconnect the host, SIZE_HBUF command always switches to the stream mode */
  	vx_send_rih(chip, IRQ_CONNECT_STREAM_NEXT);
  	/* read the last pending 6 bytes */
  	count = DMA_READ_ALIGN;
  	while (count > 0) {
  		vx_pcm_read_per_bytes(chip, runtime, pipe);
  		count -= 3;
  	}
  	/* update the position */
  	pipe->transferred += size;
  	if (pipe->transferred >= pipe->period_bytes) {
  		pipe->transferred %= pipe->period_bytes;
  		snd_pcm_period_elapsed(subs);
  	}
  	return;
  
   _error:
  	/* disconnect the host, SIZE_HBUF command always switches to the stream mode */
  	vx_send_rih(chip, IRQ_CONNECT_STREAM_NEXT);
  	return;
  }
  
  /*
   * vx_pcm_capture_pointer - pointer callback for capture
   */
  static snd_pcm_uframes_t vx_pcm_capture_pointer(struct snd_pcm_substream *subs)
  {
  	struct snd_pcm_runtime *runtime = subs->runtime;
  	struct vx_pipe *pipe = runtime->private_data;
  	return bytes_to_frames(runtime, pipe->hw_ptr);
  }
  
  /*
   * operators for PCM capture
   */
  static struct snd_pcm_ops vx_pcm_capture_ops = {
  	.open =		vx_pcm_capture_open,
  	.close =	vx_pcm_capture_close,
  	.ioctl =	snd_pcm_lib_ioctl,
  	.hw_params =	vx_pcm_hw_params,
  	.hw_free =	vx_pcm_hw_free,
  	.prepare =	vx_pcm_prepare,
  	.trigger =	vx_pcm_trigger,
  	.pointer =	vx_pcm_capture_pointer,
  	.page =		snd_pcm_lib_get_vmalloc_page,
  	.mmap =		snd_pcm_lib_mmap_vmalloc,
  };
  
  
  /*
   * interrupt handler for pcm streams
   */
  void vx_pcm_update_intr(struct vx_core *chip, unsigned int events)
  {
  	unsigned int i;
  	struct vx_pipe *pipe;
  
  #define EVENT_MASK	(END_OF_BUFFER_EVENTS_PENDING|ASYNC_EVENTS_PENDING)
  
  	if (events & EVENT_MASK) {
  		vx_init_rmh(&chip->irq_rmh, CMD_ASYNC);
  		if (events & ASYNC_EVENTS_PENDING)
  			chip->irq_rmh.Cmd[0] |= 0x00000001;	/* SEL_ASYNC_EVENTS */
  		if (events & END_OF_BUFFER_EVENTS_PENDING)
  			chip->irq_rmh.Cmd[0] |= 0x00000002;	/* SEL_END_OF_BUF_EVENTS */
  
  		if (vx_send_msg(chip, &chip->irq_rmh) < 0) {
  			snd_printdd(KERN_ERR "msg send error!!
  ");
  			return;
  		}
  
  		i = 1;
  		while (i < chip->irq_rmh.LgStat) {
  			int p, buf, capture, eob;
  			p = chip->irq_rmh.Stat[i] & MASK_FIRST_FIELD;
  			capture = (chip->irq_rmh.Stat[i] & 0x400000) ? 1 : 0;
  			eob = (chip->irq_rmh.Stat[i] & 0x800000) ? 1 : 0;
  			i++;
  			if (events & ASYNC_EVENTS_PENDING)
  				i++;
  			buf = 1; /* force to transfer */
  			if (events & END_OF_BUFFER_EVENTS_PENDING) {
  				if (eob)
  					buf = chip->irq_rmh.Stat[i];
  				i++;
  			}
  			if (capture)
  				continue;
  			if (snd_BUG_ON(p < 0 || p >= chip->audio_outs))
  				continue;
  			pipe = chip->playback_pipes[p];
  			if (pipe && pipe->substream) {
  				vx_pcm_playback_update(chip, pipe->substream, pipe);
  				vx_pcm_playback_transfer(chip, pipe->substream, pipe, buf);
  			}
  		}
  	}
  
  	/* update the capture pcm pointers as frequently as possible */
  	for (i = 0; i < chip->audio_ins; i++) {
  		pipe = chip->capture_pipes[i];
  		if (pipe && pipe->substream)
  			vx_pcm_capture_update(chip, pipe->substream, pipe);
  	}
  }
  
  
  /*
   * vx_init_audio_io - check the available audio i/o and allocate pipe arrays
   */
  static int vx_init_audio_io(struct vx_core *chip)
  {
  	struct vx_rmh rmh;
  	int preferred;
  
  	vx_init_rmh(&rmh, CMD_SUPPORTED);
  	if (vx_send_msg(chip, &rmh) < 0) {
  		snd_printk(KERN_ERR "vx: cannot get the supported audio data
  ");
  		return -ENXIO;
  	}
  
  	chip->audio_outs = rmh.Stat[0] & MASK_FIRST_FIELD;
  	chip->audio_ins = (rmh.Stat[0] >> (FIELD_SIZE*2)) & MASK_FIRST_FIELD;
  	chip->audio_info = rmh.Stat[1];
  
  	/* allocate pipes */
  	chip->playback_pipes = kcalloc(chip->audio_outs, sizeof(struct vx_pipe *), GFP_KERNEL);
  	if (!chip->playback_pipes)
  		return -ENOMEM;
  	chip->capture_pipes = kcalloc(chip->audio_ins, sizeof(struct vx_pipe *), GFP_KERNEL);
  	if (!chip->capture_pipes) {
  		kfree(chip->playback_pipes);
  		return -ENOMEM;
  	}
  
  	preferred = chip->ibl.size;
  	chip->ibl.size = 0;
  	vx_set_ibl(chip, &chip->ibl); /* query the info */
  	if (preferred > 0) {
  		chip->ibl.size = ((preferred + chip->ibl.granularity - 1) /
  				  chip->ibl.granularity) * chip->ibl.granularity;
  		if (chip->ibl.size > chip->ibl.max_size)
  			chip->ibl.size = chip->ibl.max_size;
  	} else
  		chip->ibl.size = chip->ibl.min_size; /* set to the minimum */
  	vx_set_ibl(chip, &chip->ibl);
  
  	return 0;
  }
  
  
  /*
   * free callback for pcm
   */
  static void snd_vx_pcm_free(struct snd_pcm *pcm)
  {
  	struct vx_core *chip = pcm->private_data;
  	chip->pcm[pcm->device] = NULL;
  	kfree(chip->playback_pipes);
  	chip->playback_pipes = NULL;
  	kfree(chip->capture_pipes);
  	chip->capture_pipes = NULL;
  }
  
  /*
   * snd_vx_pcm_new - create and initialize a pcm
   */
  int snd_vx_pcm_new(struct vx_core *chip)
  {
  	struct snd_pcm *pcm;
  	unsigned int i;
  	int err;
  
  	if ((err = vx_init_audio_io(chip)) < 0)
  		return err;
  
  	for (i = 0; i < chip->hw->num_codecs; i++) {
  		unsigned int outs, ins;
  		outs = chip->audio_outs > i * 2 ? 1 : 0;
  		ins = chip->audio_ins > i * 2 ? 1 : 0;
  		if (! outs && ! ins)
  			break;
  		err = snd_pcm_new(chip->card, "VX PCM", i,
  				  outs, ins, &pcm);
  		if (err < 0)
  			return err;
  		if (outs)
  			snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &vx_pcm_playback_ops);
  		if (ins)
  			snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &vx_pcm_capture_ops);
  
  		pcm->private_data = chip;
  		pcm->private_free = snd_vx_pcm_free;
  		pcm->info_flags = 0;
  		pcm->nonatomic = true;
  		strcpy(pcm->name, chip->card->shortname);
  		chip->pcm[i] = pcm;
  	}
  
  	return 0;
  }