sound/soc/fsl/mpc5200_dma.c - kernel/msm-4.19 - Gitiles

 /*
  * Freescale MPC5200 PSC DMA
  * ALSA SoC Platform driver
  *
  * Copyright (C) 2008 Secret Lab Technologies Ltd.
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/device.h>
 #include <linux/delay.h>
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/dma-mapping.h>

 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
 #include <sound/initval.h>
 #include <sound/soc.h>
 #include <sound/soc-of-simple.h>

 #include <sysdev/bestcomm/bestcomm.h>
 #include <sysdev/bestcomm/gen_bd.h>
 #include <asm/mpc52xx_psc.h>

 #include "mpc5200_dma.h"

 MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
 MODULE_DESCRIPTION("Freescale MPC5200 PSC in DMA mode ASoC Driver");
 MODULE_LICENSE("GPL");

 /*
  * Interrupt handlers
  */
 static irqreturn_t psc_i2s_status_irq(int irq, void *_psc_i2s)
 {
 	struct psc_i2s *psc_i2s = _psc_i2s;
 	struct mpc52xx_psc __iomem *regs = psc_i2s->psc_regs;
 	u16 isr;

 	isr = in_be16(&regs->mpc52xx_psc_isr);

 	/* Playback underrun error */
 	if (psc_i2s->playback.active && (isr & MPC52xx_PSC_IMR_TXEMP))
 		psc_i2s->stats.underrun_count++;

 	/* Capture overrun error */
 	if (psc_i2s->capture.active && (isr & MPC52xx_PSC_IMR_ORERR))
 		psc_i2s->stats.overrun_count++;

 	out_8(&regs->command, 4 << 4);	/* reset the error status */

 	return IRQ_HANDLED;
 }

 /**
  * psc_i2s_bcom_enqueue_next_buffer - Enqueue another audio buffer
  * @s: pointer to stream private data structure
  *
  * Enqueues another audio period buffer into the bestcomm queue.
  *
  * Note: The routine must only be called when there is space available in
  * the queue.  Otherwise the enqueue will fail and the audio ring buffer
  * will get out of sync
  */
 static void psc_i2s_bcom_enqueue_next_buffer(struct psc_i2s_stream *s)
 {
 	struct bcom_bd *bd;

 	/* Prepare and enqueue the next buffer descriptor */
 	bd = bcom_prepare_next_buffer(s->bcom_task);
 	bd->status = s->period_bytes;
 	bd->data[0] = s->period_next_pt;
 	bcom_submit_next_buffer(s->bcom_task, NULL);

 	/* Update for next period */
 	s->period_next_pt += s->period_bytes;
 	if (s->period_next_pt >= s->period_end)
 		s->period_next_pt = s->period_start;
 }

 /* Bestcomm DMA irq handler */
 static irqreturn_t psc_i2s_bcom_irq(int irq, void *_psc_i2s_stream)
 {
 	struct psc_i2s_stream *s = _psc_i2s_stream;

 	/* For each finished period, dequeue the completed period buffer
 	 * and enqueue a new one in it's place. */
 	while (bcom_buffer_done(s->bcom_task)) {
 		bcom_retrieve_buffer(s->bcom_task, NULL, NULL);
 		s->period_current_pt += s->period_bytes;
 		if (s->period_current_pt >= s->period_end)
 			s->period_current_pt = s->period_start;
 		psc_i2s_bcom_enqueue_next_buffer(s);
 		bcom_enable(s->bcom_task);
 	}

 	/* If the stream is active, then also inform the PCM middle layer
 	 * of the period finished event. */
 	if (s->active)
 		snd_pcm_period_elapsed(s->stream);

 	return IRQ_HANDLED;
 }

 /**
  * psc_i2s_startup: create a new substream
  *
  * This is the first function called when a stream is opened.
  *
  * If this is the first stream open, then grab the IRQ and program most of
  * the PSC registers.
  */
 int psc_i2s_startup(struct snd_pcm_substream *substream,
 			   struct snd_soc_dai *dai)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
 	int rc;

 	dev_dbg(psc_i2s->dev, "psc_i2s_startup(substream=%p)\n", substream);

 	if (!psc_i2s->playback.active &&
 	    !psc_i2s->capture.active) {
 		/* Setup the IRQs */
 		rc = request_irq(psc_i2s->irq, &psc_i2s_status_irq, IRQF_SHARED,
 				 "psc-i2s-status", psc_i2s);
 		rc |= request_irq(psc_i2s->capture.irq,
 				  &psc_i2s_bcom_irq, IRQF_SHARED,
 				  "psc-i2s-capture", &psc_i2s->capture);
 		rc |= request_irq(psc_i2s->playback.irq,
 				  &psc_i2s_bcom_irq, IRQF_SHARED,
 				  "psc-i2s-playback", &psc_i2s->playback);
 		if (rc) {
 			free_irq(psc_i2s->irq, psc_i2s);
 			free_irq(psc_i2s->capture.irq,
 				 &psc_i2s->capture);
 			free_irq(psc_i2s->playback.irq,
 				 &psc_i2s->playback);
 			return -ENODEV;
 		}
 	}

 	return 0;
 }

 int psc_i2s_hw_free(struct snd_pcm_substream *substream,
 			   struct snd_soc_dai *dai)
 {
 	snd_pcm_set_runtime_buffer(substream, NULL);
 	return 0;
 }

 /**
  * psc_i2s_trigger: start and stop the DMA transfer.
  *
  * This function is called by ALSA to start, stop, pause, and resume the DMA
  * transfer of data.
  */
 int psc_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
 			   struct snd_soc_dai *dai)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct psc_i2s_stream *s;
 	struct mpc52xx_psc __iomem *regs = psc_i2s->psc_regs;
 	u16 imr;
 	u8 psc_cmd;
 	unsigned long flags;

 	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
 		s = &psc_i2s->capture;
 	else
 		s = &psc_i2s->playback;

 	dev_dbg(psc_i2s->dev, "psc_i2s_trigger(substream=%p, cmd=%i)"
 		" stream_id=%i\n",
 		substream, cmd, substream->pstr->stream);

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		s->period_bytes = frames_to_bytes(runtime,
 						  runtime->period_size);
 		s->period_start = virt_to_phys(runtime->dma_area);
 		s->period_end = s->period_start +
 				(s->period_bytes * runtime->periods);
 		s->period_next_pt = s->period_start;
 		s->period_current_pt = s->period_start;
 		s->active = 1;

 		/* First; reset everything */
 		if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) {
 			out_8(&regs->command, MPC52xx_PSC_RST_RX);
 			out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);
 		} else {
 			out_8(&regs->command, MPC52xx_PSC_RST_TX);
 			out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);
 		}

 		/* Next, fill up the bestcomm bd queue and enable DMA.
 		 * This will begin filling the PSC's fifo. */
 		if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
 			bcom_gen_bd_rx_reset(s->bcom_task);
 		else
 			bcom_gen_bd_tx_reset(s->bcom_task);
 		while (!bcom_queue_full(s->bcom_task))
 			psc_i2s_bcom_enqueue_next_buffer(s);
 		bcom_enable(s->bcom_task);

 		/* Due to errata in the i2s mode; need to line up enabling
 		 * the transmitter with a transition on the frame sync
 		 * line */

 		spin_lock_irqsave(&psc_i2s->lock, flags);
 		/* first make sure it is low */
 		while ((in_8(&regs->ipcr_acr.ipcr) & 0x80) != 0)
 			;
 		/* then wait for the transition to high */
 		while ((in_8(&regs->ipcr_acr.ipcr) & 0x80) == 0)
 			;
 		/* Finally, enable the PSC.
 		 * Receiver must always be enabled; even when we only want
 		 * transmit.  (see 15.3.2.3 of MPC5200B User's Guide) */
 		psc_cmd = MPC52xx_PSC_RX_ENABLE;
 		if (substream->pstr->stream == SNDRV_PCM_STREAM_PLAYBACK)
 			psc_cmd |= MPC52xx_PSC_TX_ENABLE;
 		out_8(&regs->command, psc_cmd);
 		spin_unlock_irqrestore(&psc_i2s->lock, flags);

 		break;

 	case SNDRV_PCM_TRIGGER_STOP:
 		/* Turn off the PSC */
 		s->active = 0;
 		if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) {
 			if (!psc_i2s->playback.active) {
 				out_8(&regs->command, 2 << 4);	/* reset rx */
 				out_8(&regs->command, 3 << 4);	/* reset tx */
 				out_8(&regs->command, 4 << 4);	/* reset err */
 			}
 		} else {
 			out_8(&regs->command, 3 << 4);	/* reset tx */
 			out_8(&regs->command, 4 << 4);	/* reset err */
 			if (!psc_i2s->capture.active)
 				out_8(&regs->command, 2 << 4);	/* reset rx */
 		}

 		bcom_disable(s->bcom_task);
 		while (!bcom_queue_empty(s->bcom_task))
 			bcom_retrieve_buffer(s->bcom_task, NULL, NULL);

 		break;

 	default:
 		dev_dbg(psc_i2s->dev, "invalid command\n");
 		return -EINVAL;
 	}

 	/* Update interrupt enable settings */
 	imr = 0;
 	if (psc_i2s->playback.active)
 		imr |= MPC52xx_PSC_IMR_TXEMP;
 	if (psc_i2s->capture.active)
 		imr |= MPC52xx_PSC_IMR_ORERR;
 	out_be16(&regs->isr_imr.imr, imr);

 	return 0;
 }

 /**
  * psc_i2s_shutdown: shutdown the data transfer on a stream
  *
  * Shutdown the PSC if there are no other substreams open.
  */
 void psc_i2s_shutdown(struct snd_pcm_substream *substream,
 			     struct snd_soc_dai *dai)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;

 	dev_dbg(psc_i2s->dev, "psc_i2s_shutdown(substream=%p)\n", substream);

 	/*
 	 * If this is the last active substream, disable the PSC and release
 	 * the IRQ.
 	 */
 	if (!psc_i2s->playback.active &&
 	    !psc_i2s->capture.active) {

 		/* Disable all interrupts and reset the PSC */
 		out_be16(&psc_i2s->psc_regs->isr_imr.imr, 0);
 		out_8(&psc_i2s->psc_regs->command, 3 << 4); /* reset tx */
 		out_8(&psc_i2s->psc_regs->command, 2 << 4); /* reset rx */
 		out_8(&psc_i2s->psc_regs->command, 1 << 4); /* reset mode */
 		out_8(&psc_i2s->psc_regs->command, 4 << 4); /* reset error */

 		/* Release irqs */
 		free_irq(psc_i2s->irq, psc_i2s);
 		free_irq(psc_i2s->capture.irq, &psc_i2s->capture);
 		free_irq(psc_i2s->playback.irq, &psc_i2s->playback);
 	}
 }

 /* ---------------------------------------------------------------------
  * The PSC DMA 'ASoC platform' driver
  *
  * Can be referenced by an 'ASoC machine' driver
  * This driver only deals with the audio bus; it doesn't have any
  * interaction with the attached codec
  */

 static const struct snd_pcm_hardware psc_i2s_pcm_hardware = {
 	.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
 		SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
 		SNDRV_PCM_INFO_BATCH,
 	.formats = SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_BE |
 		   SNDRV_PCM_FMTBIT_S24_BE | SNDRV_PCM_FMTBIT_S32_BE,
 	.rate_min = 8000,
 	.rate_max = 48000,
 	.channels_min = 2,
 	.channels_max = 2,
 	.period_bytes_max	= 1024 * 1024,
 	.period_bytes_min	= 32,
 	.periods_min		= 2,
 	.periods_max		= 256,
 	.buffer_bytes_max	= 2 * 1024 * 1024,
 	.fifo_size		= 0,
 };

 static int psc_i2s_pcm_open(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
 	struct psc_i2s_stream *s;

 	dev_dbg(psc_i2s->dev, "psc_i2s_pcm_open(substream=%p)\n", substream);

 	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
 		s = &psc_i2s->capture;
 	else
 		s = &psc_i2s->playback;

 	snd_soc_set_runtime_hwparams(substream, &psc_i2s_pcm_hardware);

 	s->stream = substream;
 	return 0;
 }

 static int psc_i2s_pcm_close(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
 	struct psc_i2s_stream *s;

 	dev_dbg(psc_i2s->dev, "psc_i2s_pcm_close(substream=%p)\n", substream);

 	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
 		s = &psc_i2s->capture;
 	else
 		s = &psc_i2s->playback;

 	s->stream = NULL;
 	return 0;
 }

 static snd_pcm_uframes_t
 psc_i2s_pcm_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
 	struct psc_i2s_stream *s;
 	dma_addr_t count;

 	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
 		s = &psc_i2s->capture;
 	else
 		s = &psc_i2s->playback;

 	count = s->period_current_pt - s->period_start;

 	return bytes_to_frames(substream->runtime, count);
 }

 static struct snd_pcm_ops psc_i2s_pcm_ops = {
 	.open		= psc_i2s_pcm_open,
 	.close		= psc_i2s_pcm_close,
 	.ioctl		= snd_pcm_lib_ioctl,
 	.pointer	= psc_i2s_pcm_pointer,
 };

 static u64 psc_i2s_pcm_dmamask = 0xffffffff;
 static int psc_i2s_pcm_new(struct snd_card *card, struct snd_soc_dai *dai,
 			   struct snd_pcm *pcm)
 {
 	struct snd_soc_pcm_runtime *rtd = pcm->private_data;
 	size_t size = psc_i2s_pcm_hardware.buffer_bytes_max;
 	int rc = 0;

 	dev_dbg(rtd->socdev->dev, "psc_i2s_pcm_new(card=%p, dai=%p, pcm=%p)\n",
 		card, dai, pcm);

 	if (!card->dev->dma_mask)
 		card->dev->dma_mask = &psc_i2s_pcm_dmamask;
 	if (!card->dev->coherent_dma_mask)
 		card->dev->coherent_dma_mask = 0xffffffff;

 	if (pcm->streams[0].substream) {
 		rc = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->dev, size,
 					&pcm->streams[0].substream->dma_buffer);
 		if (rc)
 			goto playback_alloc_err;
 	}

 	if (pcm->streams[1].substream) {
 		rc = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->dev, size,
 					&pcm->streams[1].substream->dma_buffer);
 		if (rc)
 			goto capture_alloc_err;
 	}

 	return 0;

  capture_alloc_err:
 	if (pcm->streams[0].substream)
 		snd_dma_free_pages(&pcm->streams[0].substream->dma_buffer);
  playback_alloc_err:
 	dev_err(card->dev, "Cannot allocate buffer(s)\n");
 	return -ENOMEM;
 }

 static void psc_i2s_pcm_free(struct snd_pcm *pcm)
 {
 	struct snd_soc_pcm_runtime *rtd = pcm->private_data;
 	struct snd_pcm_substream *substream;
 	int stream;

 	dev_dbg(rtd->socdev->dev, "psc_i2s_pcm_free(pcm=%p)\n", pcm);

 	for (stream = 0; stream < 2; stream++) {
 		substream = pcm->streams[stream].substream;
 		if (substream) {
 			snd_dma_free_pages(&substream->dma_buffer);
 			substream->dma_buffer.area = NULL;
 			substream->dma_buffer.addr = 0;
 		}
 	}
 }

 struct snd_soc_platform psc_i2s_pcm_soc_platform = {
 	.name		= "mpc5200-psc-audio",
 	.pcm_ops	= &psc_i2s_pcm_ops,
 	.pcm_new	= &psc_i2s_pcm_new,
 	.pcm_free	= &psc_i2s_pcm_free,
 };
	/*
	* Freescale MPC5200 PSC DMA
	* ALSA SoC Platform driver
	*
	* Copyright (C) 2008 Secret Lab Technologies Ltd.
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/device.h>
	#include <linux/delay.h>
	#include <linux/of_device.h>
	#include <linux/of_platform.h>
	#include <linux/dma-mapping.h>

	#include <sound/core.h>
	#include <sound/pcm.h>
	#include <sound/pcm_params.h>
	#include <sound/initval.h>
	#include <sound/soc.h>
	#include <sound/soc-of-simple.h>

	#include <sysdev/bestcomm/bestcomm.h>
	#include <sysdev/bestcomm/gen_bd.h>
	#include <asm/mpc52xx_psc.h>

	#include "mpc5200_dma.h"

	MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
	MODULE_DESCRIPTION("Freescale MPC5200 PSC in DMA mode ASoC Driver");
	MODULE_LICENSE("GPL");

	/*
	* Interrupt handlers
	*/
	static irqreturn_t psc_i2s_status_irq(int irq, void *_psc_i2s)
	{
	struct psc_i2s *psc_i2s = _psc_i2s;
	struct mpc52xx_psc __iomem *regs = psc_i2s->psc_regs;
	u16 isr;

	isr = in_be16(&regs->mpc52xx_psc_isr);

	/* Playback underrun error */
	if (psc_i2s->playback.active && (isr & MPC52xx_PSC_IMR_TXEMP))
	psc_i2s->stats.underrun_count++;

	/* Capture overrun error */
	if (psc_i2s->capture.active && (isr & MPC52xx_PSC_IMR_ORERR))
	psc_i2s->stats.overrun_count++;

	out_8(&regs->command, 4 << 4); /* reset the error status */

	return IRQ_HANDLED;
	}

	/**
	* psc_i2s_bcom_enqueue_next_buffer - Enqueue another audio buffer
	* @s: pointer to stream private data structure
	*
	* Enqueues another audio period buffer into the bestcomm queue.
	*
	* Note: The routine must only be called when there is space available in
	* the queue. Otherwise the enqueue will fail and the audio ring buffer
	* will get out of sync
	*/
	static void psc_i2s_bcom_enqueue_next_buffer(struct psc_i2s_stream *s)
	{
	struct bcom_bd *bd;

	/* Prepare and enqueue the next buffer descriptor */
	bd = bcom_prepare_next_buffer(s->bcom_task);
	bd->status = s->period_bytes;
	bd->data[0] = s->period_next_pt;
	bcom_submit_next_buffer(s->bcom_task, NULL);

	/* Update for next period */
	s->period_next_pt += s->period_bytes;
	if (s->period_next_pt >= s->period_end)
	s->period_next_pt = s->period_start;
	}

	/* Bestcomm DMA irq handler */
	static irqreturn_t psc_i2s_bcom_irq(int irq, void *_psc_i2s_stream)
	{
	struct psc_i2s_stream *s = _psc_i2s_stream;

	/* For each finished period, dequeue the completed period buffer
	* and enqueue a new one in it's place. */
	while (bcom_buffer_done(s->bcom_task)) {
	bcom_retrieve_buffer(s->bcom_task, NULL, NULL);
	s->period_current_pt += s->period_bytes;
	if (s->period_current_pt >= s->period_end)
	s->period_current_pt = s->period_start;
	psc_i2s_bcom_enqueue_next_buffer(s);
	bcom_enable(s->bcom_task);
	}

	/* If the stream is active, then also inform the PCM middle layer
	* of the period finished event. */
	if (s->active)
	snd_pcm_period_elapsed(s->stream);

	return IRQ_HANDLED;
	}

	/**
	* psc_i2s_startup: create a new substream
	*
	* This is the first function called when a stream is opened.
	*
	* If this is the first stream open, then grab the IRQ and program most of
	* the PSC registers.
	*/
	int psc_i2s_startup(struct snd_pcm_substream *substream,
	struct snd_soc_dai *dai)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
	int rc;

	dev_dbg(psc_i2s->dev, "psc_i2s_startup(substream=%p)\n", substream);

	if (!psc_i2s->playback.active &&
	!psc_i2s->capture.active) {
	/* Setup the IRQs */
	rc = request_irq(psc_i2s->irq, &psc_i2s_status_irq, IRQF_SHARED,
	"psc-i2s-status", psc_i2s);
	rc \|= request_irq(psc_i2s->capture.irq,
	&psc_i2s_bcom_irq, IRQF_SHARED,
	"psc-i2s-capture", &psc_i2s->capture);
	rc \|= request_irq(psc_i2s->playback.irq,
	&psc_i2s_bcom_irq, IRQF_SHARED,
	"psc-i2s-playback", &psc_i2s->playback);
	if (rc) {
	free_irq(psc_i2s->irq, psc_i2s);
	free_irq(psc_i2s->capture.irq,
	&psc_i2s->capture);
	free_irq(psc_i2s->playback.irq,
	&psc_i2s->playback);
	return -ENODEV;
	}
	}

	return 0;
	}

	int psc_i2s_hw_free(struct snd_pcm_substream *substream,
	struct snd_soc_dai *dai)
	{
	snd_pcm_set_runtime_buffer(substream, NULL);
	return 0;
	}

	/**
	* psc_i2s_trigger: start and stop the DMA transfer.
	*
	* This function is called by ALSA to start, stop, pause, and resume the DMA
	* transfer of data.
	*/
	int psc_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
	struct snd_soc_dai *dai)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct psc_i2s_stream *s;
	struct mpc52xx_psc __iomem *regs = psc_i2s->psc_regs;
	u16 imr;
	u8 psc_cmd;
	unsigned long flags;

	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
	s = &psc_i2s->capture;
	else
	s = &psc_i2s->playback;

	dev_dbg(psc_i2s->dev, "psc_i2s_trigger(substream=%p, cmd=%i)"
	" stream_id=%i\n",
	substream, cmd, substream->pstr->stream);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	s->period_bytes = frames_to_bytes(runtime,
	runtime->period_size);
	s->period_start = virt_to_phys(runtime->dma_area);
	s->period_end = s->period_start +
	(s->period_bytes * runtime->periods);
	s->period_next_pt = s->period_start;
	s->period_current_pt = s->period_start;
	s->active = 1;

	/* First; reset everything */
	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) {
	out_8(&regs->command, MPC52xx_PSC_RST_RX);
	out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);
	} else {
	out_8(&regs->command, MPC52xx_PSC_RST_TX);
	out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);
	}

	/* Next, fill up the bestcomm bd queue and enable DMA.
	* This will begin filling the PSC's fifo. */
	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
	bcom_gen_bd_rx_reset(s->bcom_task);
	else
	bcom_gen_bd_tx_reset(s->bcom_task);
	while (!bcom_queue_full(s->bcom_task))
	psc_i2s_bcom_enqueue_next_buffer(s);
	bcom_enable(s->bcom_task);

	/* Due to errata in the i2s mode; need to line up enabling
	* the transmitter with a transition on the frame sync
	* line */

	spin_lock_irqsave(&psc_i2s->lock, flags);
	/* first make sure it is low */
	while ((in_8(&regs->ipcr_acr.ipcr) & 0x80) != 0)
	;
	/* then wait for the transition to high */
	while ((in_8(&regs->ipcr_acr.ipcr) & 0x80) == 0)
	;
	/* Finally, enable the PSC.
	* Receiver must always be enabled; even when we only want
	* transmit. (see 15.3.2.3 of MPC5200B User's Guide) */
	psc_cmd = MPC52xx_PSC_RX_ENABLE;
	if (substream->pstr->stream == SNDRV_PCM_STREAM_PLAYBACK)
	psc_cmd \|= MPC52xx_PSC_TX_ENABLE;
	out_8(&regs->command, psc_cmd);
	spin_unlock_irqrestore(&psc_i2s->lock, flags);

	break;

	case SNDRV_PCM_TRIGGER_STOP:
	/* Turn off the PSC */
	s->active = 0;
	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) {
	if (!psc_i2s->playback.active) {
	out_8(&regs->command, 2 << 4); /* reset rx */
	out_8(&regs->command, 3 << 4); /* reset tx */
	out_8(&regs->command, 4 << 4); /* reset err */
	}
	} else {
	out_8(&regs->command, 3 << 4); /* reset tx */
	out_8(&regs->command, 4 << 4); /* reset err */
	if (!psc_i2s->capture.active)
	out_8(&regs->command, 2 << 4); /* reset rx */
	}

	bcom_disable(s->bcom_task);
	while (!bcom_queue_empty(s->bcom_task))
	bcom_retrieve_buffer(s->bcom_task, NULL, NULL);

	break;

	default:
	dev_dbg(psc_i2s->dev, "invalid command\n");
	return -EINVAL;
	}

	/* Update interrupt enable settings */
	imr = 0;
	if (psc_i2s->playback.active)
	imr \|= MPC52xx_PSC_IMR_TXEMP;
	if (psc_i2s->capture.active)
	imr \|= MPC52xx_PSC_IMR_ORERR;
	out_be16(&regs->isr_imr.imr, imr);

	return 0;
	}

	/**
	* psc_i2s_shutdown: shutdown the data transfer on a stream
	*
	* Shutdown the PSC if there are no other substreams open.
	*/
	void psc_i2s_shutdown(struct snd_pcm_substream *substream,
	struct snd_soc_dai *dai)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;

	dev_dbg(psc_i2s->dev, "psc_i2s_shutdown(substream=%p)\n", substream);

	/*
	* If this is the last active substream, disable the PSC and release
	* the IRQ.
	*/
	if (!psc_i2s->playback.active &&
	!psc_i2s->capture.active) {

	/* Disable all interrupts and reset the PSC */
	out_be16(&psc_i2s->psc_regs->isr_imr.imr, 0);
	out_8(&psc_i2s->psc_regs->command, 3 << 4); /* reset tx */
	out_8(&psc_i2s->psc_regs->command, 2 << 4); /* reset rx */
	out_8(&psc_i2s->psc_regs->command, 1 << 4); /* reset mode */
	out_8(&psc_i2s->psc_regs->command, 4 << 4); /* reset error */

	/* Release irqs */
	free_irq(psc_i2s->irq, psc_i2s);
	free_irq(psc_i2s->capture.irq, &psc_i2s->capture);
	free_irq(psc_i2s->playback.irq, &psc_i2s->playback);
	}
	}

	/* ---------------------------------------------------------------------
	* The PSC DMA 'ASoC platform' driver
	*
	* Can be referenced by an 'ASoC machine' driver
	* This driver only deals with the audio bus; it doesn't have any
	* interaction with the attached codec
	*/

	static const struct snd_pcm_hardware psc_i2s_pcm_hardware = {
	.info = SNDRV_PCM_INFO_MMAP \| SNDRV_PCM_INFO_MMAP_VALID \|
	SNDRV_PCM_INFO_INTERLEAVED \| SNDRV_PCM_INFO_BLOCK_TRANSFER \|
	SNDRV_PCM_INFO_BATCH,
	.formats = SNDRV_PCM_FMTBIT_S8 \| SNDRV_PCM_FMTBIT_S16_BE \|
	SNDRV_PCM_FMTBIT_S24_BE \| SNDRV_PCM_FMTBIT_S32_BE,
	.rate_min = 8000,
	.rate_max = 48000,
	.channels_min = 2,
	.channels_max = 2,
	.period_bytes_max = 1024 * 1024,
	.period_bytes_min = 32,
	.periods_min = 2,
	.periods_max = 256,
	.buffer_bytes_max = 2 * 1024 * 1024,
	.fifo_size = 0,
	};

	static int psc_i2s_pcm_open(struct snd_pcm_substream *substream)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
	struct psc_i2s_stream *s;

	dev_dbg(psc_i2s->dev, "psc_i2s_pcm_open(substream=%p)\n", substream);

	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
	s = &psc_i2s->capture;
	else
	s = &psc_i2s->playback;

	snd_soc_set_runtime_hwparams(substream, &psc_i2s_pcm_hardware);

	s->stream = substream;
	return 0;
	}

	static int psc_i2s_pcm_close(struct snd_pcm_substream *substream)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
	struct psc_i2s_stream *s;

	dev_dbg(psc_i2s->dev, "psc_i2s_pcm_close(substream=%p)\n", substream);

	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
	s = &psc_i2s->capture;
	else
	s = &psc_i2s->playback;

	s->stream = NULL;
	return 0;
	}

	static snd_pcm_uframes_t
	psc_i2s_pcm_pointer(struct snd_pcm_substream *substream)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
	struct psc_i2s_stream *s;
	dma_addr_t count;

	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
	s = &psc_i2s->capture;
	else
	s = &psc_i2s->playback;

	count = s->period_current_pt - s->period_start;

	return bytes_to_frames(substream->runtime, count);
	}

	static struct snd_pcm_ops psc_i2s_pcm_ops = {
	.open = psc_i2s_pcm_open,
	.close = psc_i2s_pcm_close,
	.ioctl = snd_pcm_lib_ioctl,
	.pointer = psc_i2s_pcm_pointer,
	};

	static u64 psc_i2s_pcm_dmamask = 0xffffffff;
	static int psc_i2s_pcm_new(struct snd_card card, struct snd_soc_dai dai,
	struct snd_pcm *pcm)
	{
	struct snd_soc_pcm_runtime *rtd = pcm->private_data;
	size_t size = psc_i2s_pcm_hardware.buffer_bytes_max;
	int rc = 0;

	dev_dbg(rtd->socdev->dev, "psc_i2s_pcm_new(card=%p, dai=%p, pcm=%p)\n",
	card, dai, pcm);

	if (!card->dev->dma_mask)
	card->dev->dma_mask = &psc_i2s_pcm_dmamask;
	if (!card->dev->coherent_dma_mask)
	card->dev->coherent_dma_mask = 0xffffffff;

	if (pcm->streams[0].substream) {
	rc = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->dev, size,
	&pcm->streams[0].substream->dma_buffer);
	if (rc)
	goto playback_alloc_err;
	}

	if (pcm->streams[1].substream) {
	rc = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->dev, size,
	&pcm->streams[1].substream->dma_buffer);
	if (rc)
	goto capture_alloc_err;
	}

	return 0;

	capture_alloc_err:
	if (pcm->streams[0].substream)
	snd_dma_free_pages(&pcm->streams[0].substream->dma_buffer);
	playback_alloc_err:
	dev_err(card->dev, "Cannot allocate buffer(s)\n");
	return -ENOMEM;
	}

	static void psc_i2s_pcm_free(struct snd_pcm *pcm)
	{
	struct snd_soc_pcm_runtime *rtd = pcm->private_data;
	struct snd_pcm_substream *substream;
	int stream;

	dev_dbg(rtd->socdev->dev, "psc_i2s_pcm_free(pcm=%p)\n", pcm);

	for (stream = 0; stream < 2; stream++) {
	substream = pcm->streams[stream].substream;
	if (substream) {
	snd_dma_free_pages(&substream->dma_buffer);
	substream->dma_buffer.area = NULL;
	substream->dma_buffer.addr = 0;
	}
	}
	}

	struct snd_soc_platform psc_i2s_pcm_soc_platform = {
	.name = "mpc5200-psc-audio",
	.pcm_ops = &psc_i2s_pcm_ops,
	.pcm_new = &psc_i2s_pcm_new,
	.pcm_free = &psc_i2s_pcm_free,
	};