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davinci-pcm.c

/*
 * ALSA PCM interface for the TI DAVINCI processor
 *
 * Author:      Vladimir Barinov, <vbarinov@embeddedalley.com>
 * Copyright:   (C) 2007 MontaVista Software, Inc., <source@mvista.com>
 * added SRAM ping/pong (C) 2008 Troy Kisky <troy.kisky@boundarydevices.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/kernel.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <asm/dma.h>
#include <mach/edma.h>
#include <mach/sram.h>

#include "davinci-pcm.h"

#ifdef DEBUG
static void print_buf_info(int slot, char *name)
{
      struct edmacc_param p;
      if (slot < 0)
            return;
      edma_read_slot(slot, &p);
      printk(KERN_DEBUG "%s: 0x%x, opt=%x, src=%x, a_b_cnt=%x dst=%x\n",
                  name, slot, p.opt, p.src, p.a_b_cnt, p.dst);
      printk(KERN_DEBUG "    src_dst_bidx=%x link_bcntrld=%x src_dst_cidx=%x ccnt=%x\n",
                  p.src_dst_bidx, p.link_bcntrld, p.src_dst_cidx, p.ccnt);
}
#else
static void print_buf_info(int slot, char *name)
{
}
#endif

static struct snd_pcm_hardware pcm_hardware_playback = {
      .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
             SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
             SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME),
      .formats = (SNDRV_PCM_FMTBIT_S16_LE),
      .rates = (SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000 |
              SNDRV_PCM_RATE_22050 | SNDRV_PCM_RATE_32000 |
              SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |
              SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000 |
              SNDRV_PCM_RATE_KNOT),
      .rate_min = 8000,
      .rate_max = 96000,
      .channels_min = 2,
      .channels_max = 2,
      .buffer_bytes_max = 128 * 1024,
      .period_bytes_min = 32,
      .period_bytes_max = 8 * 1024,
      .periods_min = 16,
      .periods_max = 255,
      .fifo_size = 0,
};

static struct snd_pcm_hardware pcm_hardware_capture = {
      .info = (SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
             SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
             SNDRV_PCM_INFO_PAUSE),
      .formats = (SNDRV_PCM_FMTBIT_S16_LE),
      .rates = (SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000 |
              SNDRV_PCM_RATE_22050 | SNDRV_PCM_RATE_32000 |
              SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |
              SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000 |
              SNDRV_PCM_RATE_KNOT),
      .rate_min = 8000,
      .rate_max = 96000,
      .channels_min = 2,
      .channels_max = 2,
      .buffer_bytes_max = 128 * 1024,
      .period_bytes_min = 32,
      .period_bytes_max = 8 * 1024,
      .periods_min = 16,
      .periods_max = 255,
      .fifo_size = 0,
};

/*
 * How ping/pong works....
 *
 * Playback:
 * ram_params - copys 2*ping_size from start of SDRAM to iram,
 *    links to ram_link2
 * ram_link2 - copys rest of SDRAM to iram in ping_size units,
 *    links to ram_link
 * ram_link - copys entire SDRAM to iram in ping_size uints,
 *    links to self
 *
 * asp_params - same as asp_link[0]
 * asp_link[0] - copys from lower half of iram to asp port
 *    links to asp_link[1], triggers iram copy event on completion
 * asp_link[1] - copys from upper half of iram to asp port
 *    links to asp_link[0], triggers iram copy event on completion
 *    triggers interrupt only needed to let upper SOC levels update position
 *    in stream on completion
 *
 * When playback is started:
 *    ram_params started
 *    asp_params started
 *
 * Capture:
 * ram_params - same as ram_link,
 *    links to ram_link
 * ram_link - same as playback
 *    links to self
 *
 * asp_params - same as playback
 * asp_link[0] - same as playback
 * asp_link[1] - same as playback
 *
 * When capture is started:
 *    asp_params started
 */
00129 struct davinci_runtime_data {
      spinlock_t lock;
      int period;       /* current DMA period */
      int asp_channel;  /* Master DMA channel */
      int asp_link[2];  /* asp parameter link channel, ping/pong */
      struct davinci_pcm_dma_params *params;    /* DMA params */
      int ram_channel;
      int ram_link;
      int ram_link2;
      struct edmacc_param asp_params;
      struct edmacc_param ram_params;
};

/*
 * Not used with ping/pong
 */
static void davinci_pcm_enqueue_dma(struct snd_pcm_substream *substream)
{
      struct davinci_runtime_data *prtd = substream->runtime->private_data;
      struct snd_pcm_runtime *runtime = substream->runtime;
      int link = prtd->asp_link[0];
      unsigned int period_size;
      unsigned int dma_offset;
      dma_addr_t dma_pos;
      dma_addr_t src, dst;
      unsigned short src_bidx, dst_bidx;
      unsigned short src_cidx, dst_cidx;
      unsigned int data_type;
      unsigned short acnt;
      unsigned int count;
      unsigned int fifo_level;

      period_size = snd_pcm_lib_period_bytes(substream);
      dma_offset = prtd->period * period_size;
      dma_pos = runtime->dma_addr + dma_offset;
      fifo_level = prtd->params->fifo_level;

      pr_debug("davinci_pcm: audio_set_dma_params_play channel = %d "
            "dma_ptr = %x period_size=%x\n", link, dma_pos, period_size);

      data_type = prtd->params->data_type;
      count = period_size / data_type;
      if (fifo_level)
            count /= fifo_level;

      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            src = dma_pos;
            dst = prtd->params->dma_addr;
            src_bidx = data_type;
            dst_bidx = 0;
            src_cidx = data_type * fifo_level;
            dst_cidx = 0;
      } else {
            src = prtd->params->dma_addr;
            dst = dma_pos;
            src_bidx = 0;
            dst_bidx = data_type;
            src_cidx = 0;
            dst_cidx = data_type * fifo_level;
      }

      acnt = prtd->params->acnt;
      edma_set_src(link, src, INCR, W8BIT);
      edma_set_dest(link, dst, INCR, W8BIT);

      edma_set_src_index(link, src_bidx, src_cidx);
      edma_set_dest_index(link, dst_bidx, dst_cidx);

      if (!fifo_level)
            edma_set_transfer_params(link, acnt, count, 1, 0, ASYNC);
      else
            edma_set_transfer_params(link, acnt, fifo_level, count,
                                          fifo_level, ABSYNC);

      prtd->period++;
      if (unlikely(prtd->period >= runtime->periods))
            prtd->period = 0;
}

static void davinci_pcm_dma_irq(unsigned link, u16 ch_status, void *data)
{
      struct snd_pcm_substream *substream = data;
      struct davinci_runtime_data *prtd = substream->runtime->private_data;

      print_buf_info(prtd->ram_channel, "i ram_channel");
      pr_debug("davinci_pcm: link=%d, status=0x%x\n", link, ch_status);

      if (unlikely(ch_status != DMA_COMPLETE))
            return;

      if (snd_pcm_running(substream)) {
            if (prtd->ram_channel < 0) {
                  /* No ping/pong must fix up link dma data*/
                  spin_lock(&prtd->lock);
                  davinci_pcm_enqueue_dma(substream);
                  spin_unlock(&prtd->lock);
            }
            snd_pcm_period_elapsed(substream);
      }
}

static int allocate_sram(struct snd_pcm_substream *substream, unsigned size,
            struct snd_pcm_hardware *ppcm)
{
      struct snd_dma_buffer *buf = &substream->dma_buffer;
      struct snd_dma_buffer *iram_dma = NULL;
      dma_addr_t iram_phys = 0;
      void *iram_virt = NULL;

      if (buf->private_data || !size)
            return 0;

      ppcm->period_bytes_max = size;
      iram_virt = sram_alloc(size, &iram_phys);
      if (!iram_virt)
            goto exit1;
      iram_dma = kzalloc(sizeof(*iram_dma), GFP_KERNEL);
      if (!iram_dma)
            goto exit2;
      iram_dma->area = iram_virt;
      iram_dma->addr = iram_phys;
      memset(iram_dma->area, 0, size);
      iram_dma->bytes = size;
      buf->private_data = iram_dma;
      return 0;
exit2:
      if (iram_virt)
            sram_free(iram_virt, size);
exit1:
      return -ENOMEM;
}

/*
 * Only used with ping/pong.
 * This is called after runtime->dma_addr, period_bytes and data_type are valid
 */
static int ping_pong_dma_setup(struct snd_pcm_substream *substream)
{
      unsigned short ram_src_cidx, ram_dst_cidx;
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct davinci_runtime_data *prtd = runtime->private_data;
      struct snd_dma_buffer *iram_dma =
            (struct snd_dma_buffer *)substream->dma_buffer.private_data;
      struct davinci_pcm_dma_params *params = prtd->params;
      unsigned int data_type = params->data_type;
      unsigned int acnt = params->acnt;
      /* divide by 2 for ping/pong */
      unsigned int ping_size = snd_pcm_lib_period_bytes(substream) >> 1;
      int link = prtd->asp_link[1];
      unsigned int fifo_level = prtd->params->fifo_level;
      unsigned int count;
      if ((data_type == 0) || (data_type > 4)) {
            printk(KERN_ERR "%s: data_type=%i\n", __func__, data_type);
            return -EINVAL;
      }
      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            dma_addr_t asp_src_pong = iram_dma->addr + ping_size;
            ram_src_cidx = ping_size;
            ram_dst_cidx = -ping_size;
            edma_set_src(link, asp_src_pong, INCR, W8BIT);

            link = prtd->asp_link[0];
            edma_set_src_index(link, data_type, data_type * fifo_level);
            link = prtd->asp_link[1];
            edma_set_src_index(link, data_type, data_type * fifo_level);

            link = prtd->ram_link;
            edma_set_src(link, runtime->dma_addr, INCR, W32BIT);
      } else {
            dma_addr_t asp_dst_pong = iram_dma->addr + ping_size;
            ram_src_cidx = -ping_size;
            ram_dst_cidx = ping_size;
            edma_set_dest(link, asp_dst_pong, INCR, W8BIT);

            link = prtd->asp_link[0];
            edma_set_dest_index(link, data_type, data_type * fifo_level);
            link = prtd->asp_link[1];
            edma_set_dest_index(link, data_type, data_type * fifo_level);

            link = prtd->ram_link;
            edma_set_dest(link, runtime->dma_addr, INCR, W32BIT);
      }

      if (!fifo_level) {
            count = ping_size / data_type;
            edma_set_transfer_params(prtd->asp_link[0], acnt, count,
                        1, 0, ASYNC);
            edma_set_transfer_params(prtd->asp_link[1], acnt, count,
                        1, 0, ASYNC);
      } else {
            count = ping_size / (data_type * fifo_level);
            edma_set_transfer_params(prtd->asp_link[0], acnt, fifo_level,
                        count, fifo_level, ABSYNC);
            edma_set_transfer_params(prtd->asp_link[1], acnt, fifo_level,
                        count, fifo_level, ABSYNC);
      }

      link = prtd->ram_link;
      edma_set_src_index(link, ping_size, ram_src_cidx);
      edma_set_dest_index(link, ping_size, ram_dst_cidx);
      edma_set_transfer_params(link, ping_size, 2,
                  runtime->periods, 2, ASYNC);

      /* init master params */
      edma_read_slot(prtd->asp_link[0], &prtd->asp_params);
      edma_read_slot(prtd->ram_link, &prtd->ram_params);
      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            struct edmacc_param p_ram;
            /* Copy entire iram buffer before playback started */
            prtd->ram_params.a_b_cnt = (1 << 16) | (ping_size << 1);
            /* 0 dst_bidx */
            prtd->ram_params.src_dst_bidx = (ping_size << 1);
            /* 0 dst_cidx */
            prtd->ram_params.src_dst_cidx = (ping_size << 1);
            prtd->ram_params.ccnt = 1;

            /* Skip 1st period */
            edma_read_slot(prtd->ram_link, &p_ram);
            p_ram.src += (ping_size << 1);
            p_ram.ccnt -= 1;
            edma_write_slot(prtd->ram_link2, &p_ram);
            /*
             * When 1st started, ram -> iram dma channel will fill the
             * entire iram.  Then, whenever a ping/pong asp buffer finishes,
             * 1/2 iram will be filled.
             */
            prtd->ram_params.link_bcntrld =
                  EDMA_CHAN_SLOT(prtd->ram_link2) << 5;
      }
      return 0;
}

/* 1 asp tx or rx channel using 2 parameter channels
 * 1 ram to/from iram channel using 1 parameter channel
 *
 * Playback
 * ram copy channel kicks off first,
 * 1st ram copy of entire iram buffer completion kicks off asp channel
 * asp tcc always kicks off ram copy of 1/2 iram buffer
 *
 * Record
 * asp channel starts, tcc kicks off ram copy
 */
static int request_ping_pong(struct snd_pcm_substream *substream,
            struct davinci_runtime_data *prtd,
            struct snd_dma_buffer *iram_dma)
{
      dma_addr_t asp_src_ping;
      dma_addr_t asp_dst_ping;
      int link;
      struct davinci_pcm_dma_params *params = prtd->params;

      /* Request ram master channel */
      link = prtd->ram_channel = edma_alloc_channel(EDMA_CHANNEL_ANY,
                          davinci_pcm_dma_irq, substream,
                          prtd->params->ram_chan_q);
      if (link < 0)
            goto exit1;

      /* Request ram link channel */
      link = prtd->ram_link = edma_alloc_slot(
                  EDMA_CTLR(prtd->ram_channel), EDMA_SLOT_ANY);
      if (link < 0)
            goto exit2;

      link = prtd->asp_link[1] = edma_alloc_slot(
                  EDMA_CTLR(prtd->asp_channel), EDMA_SLOT_ANY);
      if (link < 0)
            goto exit3;

      prtd->ram_link2 = -1;
      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            link = prtd->ram_link2 = edma_alloc_slot(
                  EDMA_CTLR(prtd->ram_channel), EDMA_SLOT_ANY);
            if (link < 0)
                  goto exit4;
      }
      /* circle ping-pong buffers */
      edma_link(prtd->asp_link[0], prtd->asp_link[1]);
      edma_link(prtd->asp_link[1], prtd->asp_link[0]);
      /* circle ram buffers */
      edma_link(prtd->ram_link, prtd->ram_link);

      if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            asp_src_ping = iram_dma->addr;
            asp_dst_ping = params->dma_addr;    /* fifo */
      } else {
            asp_src_ping = params->dma_addr;    /* fifo */
            asp_dst_ping = iram_dma->addr;
      }
      /* ping */
      link = prtd->asp_link[0];
      edma_set_src(link, asp_src_ping, INCR, W16BIT);
      edma_set_dest(link, asp_dst_ping, INCR, W16BIT);
      edma_set_src_index(link, 0, 0);
      edma_set_dest_index(link, 0, 0);

      edma_read_slot(link, &prtd->asp_params);
      prtd->asp_params.opt &= ~(TCCMODE | EDMA_TCC(0x3f) | TCINTEN);
      prtd->asp_params.opt |= TCCHEN | EDMA_TCC(prtd->ram_channel & 0x3f);
      edma_write_slot(link, &prtd->asp_params);

      /* pong */
      link = prtd->asp_link[1];
      edma_set_src(link, asp_src_ping, INCR, W16BIT);
      edma_set_dest(link, asp_dst_ping, INCR, W16BIT);
      edma_set_src_index(link, 0, 0);
      edma_set_dest_index(link, 0, 0);

      edma_read_slot(link, &prtd->asp_params);
      prtd->asp_params.opt &= ~(TCCMODE | EDMA_TCC(0x3f));
      /* interrupt after every pong completion */
      prtd->asp_params.opt |= TCINTEN | TCCHEN |
            EDMA_TCC(EDMA_CHAN_SLOT(prtd->ram_channel));
      edma_write_slot(link, &prtd->asp_params);

      /* ram */
      link = prtd->ram_link;
      edma_set_src(link, iram_dma->addr, INCR, W32BIT);
      edma_set_dest(link, iram_dma->addr, INCR, W32BIT);
      pr_debug("%s: audio dma channels/slots in use for ram:%u %u %u,"
            "for asp:%u %u %u\n", __func__,
            prtd->ram_channel, prtd->ram_link, prtd->ram_link2,
            prtd->asp_channel, prtd->asp_link[0],
            prtd->asp_link[1]);
      return 0;
exit4:
      edma_free_channel(prtd->asp_link[1]);
      prtd->asp_link[1] = -1;
exit3:
      edma_free_channel(prtd->ram_link);
      prtd->ram_link = -1;
exit2:
      edma_free_channel(prtd->ram_channel);
      prtd->ram_channel = -1;
exit1:
      return link;
}

static int davinci_pcm_dma_request(struct snd_pcm_substream *substream)
{
      struct snd_dma_buffer *iram_dma;
      struct davinci_runtime_data *prtd = substream->runtime->private_data;
      struct davinci_pcm_dma_params *params = prtd->params;
      int link;

      if (!params)
            return -ENODEV;

      /* Request asp master DMA channel */
      link = prtd->asp_channel = edma_alloc_channel(params->channel,
                  davinci_pcm_dma_irq, substream,
                  prtd->params->asp_chan_q);
      if (link < 0)
            goto exit1;

      /* Request asp link channels */
      link = prtd->asp_link[0] = edma_alloc_slot(
                  EDMA_CTLR(prtd->asp_channel), EDMA_SLOT_ANY);
      if (link < 0)
            goto exit2;

      iram_dma = (struct snd_dma_buffer *)substream->dma_buffer.private_data;
      if (iram_dma) {
            if (request_ping_pong(substream, prtd, iram_dma) == 0)
                  return 0;
            printk(KERN_WARNING "%s: dma channel allocation failed,"
                        "not using sram\n", __func__);
      }

      /* Issue transfer completion IRQ when the channel completes a
       * transfer, then always reload from the same slot (by a kind
       * of loopback link).  The completion IRQ handler will update
       * the reload slot with a new buffer.
       *
       * REVISIT save p_ram here after setting up everything except
       * the buffer and its length (ccnt) ... use it as a template
       * so davinci_pcm_enqueue_dma() takes less time in IRQ.
       */
      edma_read_slot(link, &prtd->asp_params);
      prtd->asp_params.opt |= TCINTEN |
            EDMA_TCC(EDMA_CHAN_SLOT(prtd->asp_channel));
      prtd->asp_params.link_bcntrld = EDMA_CHAN_SLOT(link) << 5;
      edma_write_slot(link, &prtd->asp_params);
      return 0;
exit2:
      edma_free_channel(prtd->asp_channel);
      prtd->asp_channel = -1;
exit1:
      return link;
}

static int davinci_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
      struct davinci_runtime_data *prtd = substream->runtime->private_data;
      int ret = 0;

      spin_lock(&prtd->lock);

      switch (cmd) {
      case SNDRV_PCM_TRIGGER_START:
      case SNDRV_PCM_TRIGGER_RESUME:
      case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
            edma_resume(prtd->asp_channel);
            break;
      case SNDRV_PCM_TRIGGER_STOP:
      case SNDRV_PCM_TRIGGER_SUSPEND:
      case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
            edma_pause(prtd->asp_channel);
            break;
      default:
            ret = -EINVAL;
            break;
      }

      spin_unlock(&prtd->lock);

      return ret;
}

static int davinci_pcm_prepare(struct snd_pcm_substream *substream)
{
      struct davinci_runtime_data *prtd = substream->runtime->private_data;

      if (prtd->ram_channel >= 0) {
            int ret = ping_pong_dma_setup(substream);
            if (ret < 0)
                  return ret;

            edma_write_slot(prtd->ram_channel, &prtd->ram_params);
            edma_write_slot(prtd->asp_channel, &prtd->asp_params);

            print_buf_info(prtd->ram_channel, "ram_channel");
            print_buf_info(prtd->ram_link, "ram_link");
            print_buf_info(prtd->ram_link2, "ram_link2");
            print_buf_info(prtd->asp_channel, "asp_channel");
            print_buf_info(prtd->asp_link[0], "asp_link[0]");
            print_buf_info(prtd->asp_link[1], "asp_link[1]");

            if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                  /* copy 1st iram buffer */
                  edma_start(prtd->ram_channel);
            }
            edma_start(prtd->asp_channel);
            return 0;
      }
      prtd->period = 0;
      davinci_pcm_enqueue_dma(substream);

      /* Copy self-linked parameter RAM entry into master channel */
      edma_read_slot(prtd->asp_link[0], &prtd->asp_params);
      edma_write_slot(prtd->asp_channel, &prtd->asp_params);
      davinci_pcm_enqueue_dma(substream);
      edma_start(prtd->asp_channel);

      return 0;
}

static snd_pcm_uframes_t
davinci_pcm_pointer(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct davinci_runtime_data *prtd = runtime->private_data;
      unsigned int offset;
      int asp_count;
      dma_addr_t asp_src, asp_dst;

      spin_lock(&prtd->lock);
      if (prtd->ram_channel >= 0) {
            int ram_count;
            int mod_ram;
            dma_addr_t ram_src, ram_dst;
            unsigned int period_size = snd_pcm_lib_period_bytes(substream);
            if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                  /* reading ram before asp should be safe
                   * as long as the asp transfers less than a ping size
                   * of bytes between the 2 reads
                   */
                  edma_get_position(prtd->ram_channel,
                              &ram_src, &ram_dst);
                  edma_get_position(prtd->asp_channel,
                              &asp_src, &asp_dst);
                  asp_count = asp_src - prtd->asp_params.src;
                  ram_count = ram_src - prtd->ram_params.src;
                  mod_ram = ram_count % period_size;
                  mod_ram -= asp_count;
                  if (mod_ram < 0)
                        mod_ram += period_size;
                  else if (mod_ram == 0) {
                        if (snd_pcm_running(substream))
                              mod_ram += period_size;
                  }
                  ram_count -= mod_ram;
                  if (ram_count < 0)
                        ram_count += period_size * runtime->periods;
            } else {
                  edma_get_position(prtd->ram_channel,
                              &ram_src, &ram_dst);
                  ram_count = ram_dst - prtd->ram_params.dst;
            }
            asp_count = ram_count;
      } else {
            edma_get_position(prtd->asp_channel, &asp_src, &asp_dst);
            if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                  asp_count = asp_src - runtime->dma_addr;
            else
                  asp_count = asp_dst - runtime->dma_addr;
      }
      spin_unlock(&prtd->lock);

      offset = bytes_to_frames(runtime, asp_count);
      if (offset >= runtime->buffer_size)
            offset = 0;

      return offset;
}

static int davinci_pcm_open(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct davinci_runtime_data *prtd;
      struct snd_pcm_hardware *ppcm;
      int ret = 0;
      struct snd_soc_pcm_runtime *rtd = substream->private_data;
      struct davinci_pcm_dma_params *pa;
      struct davinci_pcm_dma_params *params;

      pa = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
      if (!pa)
            return -ENODEV;
      params = &pa[substream->stream];

      ppcm = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
                  &pcm_hardware_playback : &pcm_hardware_capture;
      allocate_sram(substream, params->sram_size, ppcm);
      snd_soc_set_runtime_hwparams(substream, ppcm);
      /* ensure that buffer size is a multiple of period size */
      ret = snd_pcm_hw_constraint_integer(runtime,
                                    SNDRV_PCM_HW_PARAM_PERIODS);
      if (ret < 0)
            return ret;

      prtd = kzalloc(sizeof(struct davinci_runtime_data), GFP_KERNEL);
      if (prtd == NULL)
            return -ENOMEM;

      spin_lock_init(&prtd->lock);
      prtd->params = params;
      prtd->asp_channel = -1;
      prtd->asp_link[0] = prtd->asp_link[1] = -1;
      prtd->ram_channel = -1;
      prtd->ram_link = -1;
      prtd->ram_link2 = -1;

      runtime->private_data = prtd;

      ret = davinci_pcm_dma_request(substream);
      if (ret) {
            printk(KERN_ERR "davinci_pcm: Failed to get dma channels\n");
            kfree(prtd);
      }

      return ret;
}

static int davinci_pcm_close(struct snd_pcm_substream *substream)
{
      struct snd_pcm_runtime *runtime = substream->runtime;
      struct davinci_runtime_data *prtd = runtime->private_data;

      if (prtd->ram_channel >= 0)
            edma_stop(prtd->ram_channel);
      if (prtd->asp_channel >= 0)
            edma_stop(prtd->asp_channel);
      if (prtd->asp_link[0] >= 0)
            edma_unlink(prtd->asp_link[0]);
      if (prtd->asp_link[1] >= 0)
            edma_unlink(prtd->asp_link[1]);
      if (prtd->ram_link >= 0)
            edma_unlink(prtd->ram_link);

      if (prtd->asp_link[0] >= 0)
            edma_free_slot(prtd->asp_link[0]);
      if (prtd->asp_link[1] >= 0)
            edma_free_slot(prtd->asp_link[1]);
      if (prtd->asp_channel >= 0)
            edma_free_channel(prtd->asp_channel);
      if (prtd->ram_link >= 0)
            edma_free_slot(prtd->ram_link);
      if (prtd->ram_link2 >= 0)
            edma_free_slot(prtd->ram_link2);
      if (prtd->ram_channel >= 0)
            edma_free_channel(prtd->ram_channel);

      kfree(prtd);

      return 0;
}

static int davinci_pcm_hw_params(struct snd_pcm_substream *substream,
                         struct snd_pcm_hw_params *hw_params)
{
      return snd_pcm_lib_malloc_pages(substream,
                              params_buffer_bytes(hw_params));
}

static int davinci_pcm_hw_free(struct snd_pcm_substream *substream)
{
      return snd_pcm_lib_free_pages(substream);
}

static int davinci_pcm_mmap(struct snd_pcm_substream *substream,
                      struct vm_area_struct *vma)
{
      struct snd_pcm_runtime *runtime = substream->runtime;

      return dma_mmap_writecombine(substream->pcm->card->dev, vma,
                             runtime->dma_area,
                             runtime->dma_addr,
                             runtime->dma_bytes);
}

static struct snd_pcm_ops davinci_pcm_ops = {
      .open =     davinci_pcm_open,
      .close =    davinci_pcm_close,
      .ioctl =    snd_pcm_lib_ioctl,
      .hw_params =      davinci_pcm_hw_params,
      .hw_free =  davinci_pcm_hw_free,
      .prepare =  davinci_pcm_prepare,
      .trigger =  davinci_pcm_trigger,
      .pointer =  davinci_pcm_pointer,
      .mmap =     davinci_pcm_mmap,
};

static int davinci_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream,
            size_t size)
{
      struct snd_pcm_substream *substream = pcm->streams[stream].substream;
      struct snd_dma_buffer *buf = &substream->dma_buffer;

      buf->dev.type = SNDRV_DMA_TYPE_DEV;
      buf->dev.dev = pcm->card->dev;
      buf->private_data = NULL;
      buf->area = dma_alloc_writecombine(pcm->card->dev, size,
                                 &buf->addr, GFP_KERNEL);

      pr_debug("davinci_pcm: preallocate_dma_buffer: area=%p, addr=%p, "
            "size=%d\n", (void *) buf->area, (void *) buf->addr, size);

      if (!buf->area)
            return -ENOMEM;

      buf->bytes = size;
      return 0;
}

static void davinci_pcm_free(struct snd_pcm *pcm)
{
      struct snd_pcm_substream *substream;
      struct snd_dma_buffer *buf;
      int stream;

      for (stream = 0; stream < 2; stream++) {
            struct snd_dma_buffer *iram_dma;
            substream = pcm->streams[stream].substream;
            if (!substream)
                  continue;

            buf = &substream->dma_buffer;
            if (!buf->area)
                  continue;

            dma_free_writecombine(pcm->card->dev, buf->bytes,
                              buf->area, buf->addr);
            buf->area = NULL;
            iram_dma = buf->private_data;
            if (iram_dma) {
                  sram_free(iram_dma->area, iram_dma->bytes);
                  kfree(iram_dma);
            }
      }
}

static u64 davinci_pcm_dmamask = 0xffffffff;

static int davinci_pcm_new(struct snd_card *card,
                     struct snd_soc_dai *dai, struct snd_pcm *pcm)
{
      int ret;

      if (!card->dev->dma_mask)
            card->dev->dma_mask = &davinci_pcm_dmamask;
      if (!card->dev->coherent_dma_mask)
            card->dev->coherent_dma_mask = 0xffffffff;

      if (dai->driver->playback.channels_min) {
            ret = davinci_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_PLAYBACK,
                  pcm_hardware_playback.buffer_bytes_max);
            if (ret)
                  return ret;
      }

      if (dai->driver->capture.channels_min) {
            ret = davinci_pcm_preallocate_dma_buffer(pcm,
                  SNDRV_PCM_STREAM_CAPTURE,
                  pcm_hardware_capture.buffer_bytes_max);
            if (ret)
                  return ret;
      }

      return 0;
}

static struct snd_soc_platform_driver davinci_soc_platform = {
      .ops =            &davinci_pcm_ops,
      .pcm_new =  davinci_pcm_new,
      .pcm_free =       davinci_pcm_free,
};

static int __devinit davinci_soc_platform_probe(struct platform_device *pdev)
{
      return snd_soc_register_platform(&pdev->dev, &davinci_soc_platform);
}

static int __devexit davinci_soc_platform_remove(struct platform_device *pdev)
{
      snd_soc_unregister_platform(&pdev->dev);
      return 0;
}

static struct platform_driver davinci_pcm_driver = {
      .driver = {
                  .name = "davinci-pcm-audio",
                  .owner = THIS_MODULE,
      },

      .probe = davinci_soc_platform_probe,
      .remove = __devexit_p(davinci_soc_platform_remove),
};

static int __init snd_davinci_pcm_init(void)
{
      return platform_driver_register(&davinci_pcm_driver);
}
module_init(snd_davinci_pcm_init);

static void __exit snd_davinci_pcm_exit(void)
{
      platform_driver_unregister(&davinci_pcm_driver);
}
module_exit(snd_davinci_pcm_exit);

MODULE_AUTHOR("Vladimir Barinov");
MODULE_DESCRIPTION("TI DAVINCI PCM DMA module");
MODULE_LICENSE("GPL");

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