text: /*
   * 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 <linux/genalloc.h>
  #include <linux/platform_data/edma.h>
  
  #include <sound/core.h>
  #include <sound/pcm.h>
  #include <sound/pcm_params.h>
  #include <sound/soc.h>
  
  #include <asm/dma.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|
  		 SNDRV_PCM_INFO_BATCH),
  	.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 |
  		 SNDRV_PCM_INFO_BATCH),
  	.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
   */
  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;
  };
  
  static void davinci_pcm_period_elapsed(struct snd_pcm_substream *substream)
  {
  	struct davinci_runtime_data *prtd = substream->runtime->private_data;
  	struct snd_pcm_runtime *runtime = substream->runtime;
  
  	prtd->period++;
  	if (unlikely(prtd->period >= runtime->periods))
  		prtd->period = 0;
  }
  
  static void davinci_pcm_period_reset(struct snd_pcm_substream *substream)
  {
  	struct davinci_runtime_data *prtd = substream->runtime->private_data;
  
  	prtd->period = 0;
  }
  /*
   * 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;
  	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", prtd->asp_link[0], 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 = 4;
  		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(prtd->asp_link[0], src, INCR, W8BIT);
  	edma_set_dest(prtd->asp_link[0], dst, INCR, W8BIT);
  
  	edma_set_src_index(prtd->asp_link[0], src_bidx, src_cidx);
  	edma_set_dest_index(prtd->asp_link[0], dst_bidx, dst_cidx);
  
  	if (!fifo_level)
  		edma_set_transfer_params(prtd->asp_link[0], acnt, count, 1, 0,
  							ASYNC);
  	else
  		edma_set_transfer_params(prtd->asp_link[0], acnt,
  						fifo_level,
  						count, fifo_level,
  						ABSYNC);
  }
  
  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 != EDMA_DMA_COMPLETE))
  		return;
  
  	if (snd_pcm_running(substream)) {
  		spin_lock(&prtd->lock);
  		if (prtd->ram_channel < 0) {
  			/* No ping/pong must fix up link dma data*/
  			davinci_pcm_enqueue_dma(substream);
  		}
  		davinci_pcm_period_elapsed(substream);
  		spin_unlock(&prtd->lock);
  		snd_pcm_period_elapsed(substream);
  	}
  }
  
  #ifdef CONFIG_GENERIC_ALLOCATOR
  static int allocate_sram(struct snd_pcm_substream *substream,
  		struct gen_pool *sram_pool, 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 = gen_pool_dma_alloc(sram_pool, 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)
  		gen_pool_free(sram_pool, (unsigned)iram_virt, size);
  exit1:
  	return -ENOMEM;
  }
  
  static void davinci_free_sram(struct snd_pcm_substream *substream,
  			      struct snd_dma_buffer *iram_dma)
  {
  	struct davinci_runtime_data *prtd = substream->runtime->private_data;
  	struct gen_pool *sram_pool = prtd->params->sram_pool;
  
  	gen_pool_free(sram_pool, (unsigned) iram_dma->area, iram_dma->bytes);
  }
  #else
  static int allocate_sram(struct snd_pcm_substream *substream,
  		struct gen_pool *sram_pool, unsigned size,
  		struct snd_pcm_hardware *ppcm)
  {
  	return 0;
  }
  
  static void davinci_free_sram(struct snd_pcm_substream *substream,
  			      struct snd_dma_buffer *iram_dma)
  {
  }
  #endif
  
  /*
   * 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;
  	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(prtd->asp_link[1], asp_src_pong, INCR, W8BIT);
  
  		edma_set_src_index(prtd->asp_link[0], data_type,
  				data_type * fifo_level);
  		edma_set_src_index(prtd->asp_link[1], data_type,
  				data_type * fifo_level);
  
  		edma_set_src(prtd->ram_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(prtd->asp_link[1], asp_dst_pong, INCR, W8BIT);
  
  		edma_set_dest_index(prtd->asp_link[0], data_type,
  				data_type * fifo_level);
  		edma_set_dest_index(prtd->asp_link[1], data_type,
  				data_type * fifo_level);
  
  		edma_set_dest(prtd->ram_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);
  	}
  
  	edma_set_src_index(prtd->ram_link, ping_size, ram_src_cidx);
  	edma_set_dest_index(prtd->ram_link, ping_size, ram_dst_cidx);
  	edma_set_transfer_params(prtd->ram_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 ret;
  	struct davinci_pcm_dma_params *params = prtd->params;
  
  	/* Request ram master channel */
  	ret = prtd->ram_channel = edma_alloc_channel(EDMA_CHANNEL_ANY,
  				  davinci_pcm_dma_irq, substream,
  				  prtd->params->ram_chan_q);
  	if (ret < 0)
  		goto exit1;
  
  	/* Request ram link channel */
  	ret = prtd->ram_link = edma_alloc_slot(
  			EDMA_CTLR(prtd->ram_channel), EDMA_SLOT_ANY);
  	if (ret < 0)
  		goto exit2;
  
  	ret = prtd->asp_link[1] = edma_alloc_slot(
  			EDMA_CTLR(prtd->asp_channel), EDMA_SLOT_ANY);
  	if (ret < 0)
  		goto exit3;
  
  	prtd->ram_link2 = -1;
  	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
  		ret = prtd->ram_link2 = edma_alloc_slot(
  			EDMA_CTLR(prtd->ram_channel), EDMA_SLOT_ANY);
  		if (ret < 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 */
  	edma_set_src(prtd->asp_link[0], asp_src_ping, INCR, W16BIT);
  	edma_set_dest(prtd->asp_link[0], asp_dst_ping, INCR, W16BIT);
  	edma_set_src_index(prtd->asp_link[0], 0, 0);
  	edma_set_dest_index(prtd->asp_link[0], 0, 0);
  
  	edma_read_slot(prtd->asp_link[0], &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(prtd->asp_link[0], &prtd->asp_params);
  
  	/* pong */
  	edma_set_src(prtd->asp_link[1], asp_src_ping, INCR, W16BIT);
  	edma_set_dest(prtd->asp_link[1], asp_dst_ping, INCR, W16BIT);
  	edma_set_src_index(prtd->asp_link[1], 0, 0);
  	edma_set_dest_index(prtd->asp_link[1], 0, 0);
  
  	edma_read_slot(prtd->asp_link[1], &prtd->asp_params);
  	prtd->asp_params.opt &= ~(TCCMODE | EDMA_TCC(0x3f));
  	/* interrupt after every pong completion */
  	prtd->asp_params.opt |= TCINTEN | TCCHEN |
  		EDMA_TCC(prtd->ram_channel & 0x3f);
  	edma_write_slot(prtd->asp_link[1], &prtd->asp_params);
  
  	/* ram */
  	edma_set_src(prtd->ram_link, iram_dma->addr, INCR, W32BIT);
  	edma_set_dest(prtd->ram_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 ret;
  }
  
  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 ret;
  
  	if (!params)
  		return -ENODEV;
  
  	/* Request asp master DMA channel */
  	ret = prtd->asp_channel = edma_alloc_channel(params->channel,
  			davinci_pcm_dma_irq, substream,
  			prtd->params->asp_chan_q);
  	if (ret < 0)
  		goto exit1;
  
  	/* Request asp link channels */
  	ret = prtd->asp_link[0] = edma_alloc_slot(
  			EDMA_CTLR(prtd->asp_channel), EDMA_SLOT_ANY);
  	if (ret < 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(prtd->asp_link[0], &prtd->asp_params);
  	prtd->asp_params.opt |= TCINTEN |
  		EDMA_TCC(EDMA_CHAN_SLOT(prtd->asp_channel));
  	prtd->asp_params.link_bcntrld = EDMA_CHAN_SLOT(prtd->asp_link[0]) << 5;
  	edma_write_slot(prtd->asp_link[0], &prtd->asp_params);
  	return 0;
  exit2:
  	edma_free_channel(prtd->asp_channel);
  	prtd->asp_channel = -1;
  exit1:
  	return ret;
  }
  
  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:
  		edma_start(prtd->asp_channel);
  		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK &&
  		    prtd->ram_channel >= 0) {
  			/* copy 1st iram buffer */
  			edma_start(prtd->ram_channel);
  		}
  		break;
  	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;
  
  	davinci_pcm_period_reset(substream);
  	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]");
  
  		/*
  		 * There is a phase offset of 2 periods between the position
  		 * used by dma setup and the position reported in the pointer
  		 * function.
  		 *
  		 * The phase offset, when not using ping-pong buffers, is due to
  		 * the two consecutive calls to davinci_pcm_enqueue_dma() below.
  		 *
  		 * Whereas here, with ping-pong buffers, the phase is due to
  		 * there being an entire buffer transfer complete before the
  		 * first dma completion event triggers davinci_pcm_dma_irq().
  		 */
  		davinci_pcm_period_elapsed(substream);
  		davinci_pcm_period_elapsed(substream);
  
  		return 0;
  	}
  	davinci_pcm_enqueue_dma(substream);
  	davinci_pcm_period_elapsed(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);
  	davinci_pcm_period_elapsed(substream);
  
  	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;
  	unsigned int period_size = snd_pcm_lib_period_bytes(substream);
  
  	/*
  	 * There is a phase offset of 2 periods between the position used by dma
  	 * setup and the position reported in the pointer function. Either +2 in
  	 * the dma setup or -2 here in the pointer function (with wrapping,
  	 * both) accounts for this offset -- choose the latter since it makes
  	 * the first-time setup clearer.
  	 */
  	spin_lock(&prtd->lock);
  	asp_count = prtd->period - 2;
  	spin_unlock(&prtd->lock);
  
  	if (asp_count < 0)
  		asp_count += runtime->periods;
  	asp_count *= period_size;
  
  	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_pool, 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) {
  			davinci_free_sram(substream, iram_dma);
  			kfree(iram_dma);
  		}
  	}
  }
  
  static int davinci_pcm_new(struct snd_soc_pcm_runtime *rtd)
  {
  	struct snd_card *card = rtd->card->snd_card;
  	struct snd_pcm *pcm = rtd->pcm;
  	int ret;
  
  	ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
  	if (ret)
  		return ret;
  
  	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
  		ret = davinci_pcm_preallocate_dma_buffer(pcm,
  			SNDRV_PCM_STREAM_PLAYBACK,
  			pcm_hardware_playback.buffer_bytes_max);
  		if (ret)
  			return ret;
  	}
  
  	if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream) {
  		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,
  };
  
  int davinci_soc_platform_register(struct device *dev)
  {
  	return devm_snd_soc_register_platform(dev, &davinci_soc_platform);
  }
  EXPORT_SYMBOL_GPL(davinci_soc_platform_register);
  
  MODULE_AUTHOR("Vladimir Barinov");
  MODULE_DESCRIPTION("TI DAVINCI PCM DMA module");
  MODULE_LICENSE("GPL");
  