sound/soc/fsl/mpc5200_dma.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 //
 // Freescale MPC5200 PSC DMA
 // ALSA SoC Platform driver
 //
 // Copyright (C) 2008 Secret Lab Technologies Ltd.
 // Copyright (C) 2009 Jon Smirl, Digispeaker

 #include <linux/module.h>
 #include <linux/of_device.h>
 #include <linux/dma-mapping.h>
 #include <linux/slab.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>

 #include <sound/soc.h>

 #include <linux/fsl/bestcomm/bestcomm.h>
 #include <linux/fsl/bestcomm/gen_bd.h>
 #include <asm/mpc52xx_psc.h>

 #include "mpc5200_dma.h"

 #define DRV_NAME "mpc5200_dma"

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

 	isr = in_be16(&regs->mpc52xx_psc_isr);

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

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

 	out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);

 	return IRQ_HANDLED;
 }

 /**
  * psc_dma_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_dma_bcom_enqueue_next_buffer(struct psc_dma_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->runtime->dma_addr + (s->period_next * s->period_bytes);
 	bcom_submit_next_buffer(s->bcom_task, NULL);

 	/* Update for next period */
 	s->period_next = (s->period_next + 1) % s->runtime->periods;
 }

 /* Bestcomm DMA irq handler */
 static irqreturn_t psc_dma_bcom_irq(int irq, void *_psc_dma_stream)
 {
 	struct psc_dma_stream *s = _psc_dma_stream;

 	spin_lock(&s->psc_dma->lock);
 	/* 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 = (s->period_current+1) % s->runtime->periods;
 		s->period_count++;

 		psc_dma_bcom_enqueue_next_buffer(s);
 	}
 	spin_unlock(&s->psc_dma->lock);

 	/* 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;
 }

 static int psc_dma_hw_free(struct snd_pcm_substream *substream)
 {
 	snd_pcm_set_runtime_buffer(substream, NULL);
 	return 0;
 }

 /**
  * psc_dma_trigger: start and stop the DMA transfer.
  *
  * This function is called by ALSA to start, stop, pause, and resume the DMA
  * transfer of data.
  */
 static int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(rtd->cpu_dai);
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct psc_dma_stream *s = to_psc_dma_stream(substream, psc_dma);
 	struct mpc52xx_psc __iomem *regs = psc_dma->psc_regs;
 	u16 imr;
 	unsigned long flags;
 	int i;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 		dev_dbg(psc_dma->dev, "START: stream=%i fbits=%u ps=%u #p=%u\n",
 			substream->pstr->stream, runtime->frame_bits,
 			(int)runtime->period_size, runtime->periods);
 		s->period_bytes = frames_to_bytes(runtime,
 						  runtime->period_size);
 		s->period_next = 0;
 		s->period_current = 0;
 		s->active = 1;
 		s->period_count = 0;
 		s->runtime = runtime;

 		/* Fill up the bestcomm bd queue and enable DMA.
 		 * This will begin filling the PSC's fifo.
 		 */
 		spin_lock_irqsave(&psc_dma->lock, flags);

 		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);

 		for (i = 0; i < runtime->periods; i++)
 			if (!bcom_queue_full(s->bcom_task))
 				psc_dma_bcom_enqueue_next_buffer(s);

 		bcom_enable(s->bcom_task);
 		spin_unlock_irqrestore(&psc_dma->lock, flags);

 		out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);

 		break;

 	case SNDRV_PCM_TRIGGER_STOP:
 		dev_dbg(psc_dma->dev, "STOP: stream=%i periods_count=%i\n",
 			substream->pstr->stream, s->period_count);
 		s->active = 0;

 		spin_lock_irqsave(&psc_dma->lock, flags);
 		bcom_disable(s->bcom_task);
 		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);
 		spin_unlock_irqrestore(&psc_dma->lock, flags);

 		break;

 	default:
 		dev_dbg(psc_dma->dev, "unhandled trigger: stream=%i cmd=%i\n",
 			substream->pstr->stream, cmd);
 		return -EINVAL;
 	}

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

 	return 0;
 }


 /* ---------------------------------------------------------------------
  * 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_dma_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,
 	.period_bytes_max	= 1024 * 1024,
 	.period_bytes_min	= 32,
 	.periods_min		= 2,
 	.periods_max		= 256,
 	.buffer_bytes_max	= 2 * 1024 * 1024,
 	.fifo_size		= 512,
 };

 static int psc_dma_open(struct snd_pcm_substream *substream)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(rtd->cpu_dai);
 	struct psc_dma_stream *s;
 	int rc;

 	dev_dbg(psc_dma->dev, "psc_dma_open(substream=%p)\n", substream);

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

 	snd_soc_set_runtime_hwparams(substream, &psc_dma_hardware);

 	rc = snd_pcm_hw_constraint_integer(runtime,
 		SNDRV_PCM_HW_PARAM_PERIODS);
 	if (rc < 0) {
 		dev_err(substream->pcm->card->dev, "invalid buffer size\n");
 		return rc;
 	}

 	s->stream = substream;
 	return 0;
 }

 static int psc_dma_close(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(rtd->cpu_dai);
 	struct psc_dma_stream *s;

 	dev_dbg(psc_dma->dev, "psc_dma_close(substream=%p)\n", substream);

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

 	if (!psc_dma->playback.active &&
 	    !psc_dma->capture.active) {

 		/* Disable all interrupts and reset the PSC */
 		out_be16(&psc_dma->psc_regs->isr_imr.imr, psc_dma->imr);
 		out_8(&psc_dma->psc_regs->command, 4 << 4); /* reset error */
 	}
 	s->stream = NULL;
 	return 0;
 }

 static snd_pcm_uframes_t
 psc_dma_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(rtd->cpu_dai);
 	struct psc_dma_stream *s;
 	dma_addr_t count;

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

 	count = s->period_current * s->period_bytes;

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

 static int
 psc_dma_hw_params(struct snd_pcm_substream *substream,
 			 struct snd_pcm_hw_params *params)
 {
 	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

 	return 0;
 }

 static const struct snd_pcm_ops psc_dma_ops = {
 	.open		= psc_dma_open,
 	.close		= psc_dma_close,
 	.hw_free	= psc_dma_hw_free,
 	.ioctl		= snd_pcm_lib_ioctl,
 	.pointer	= psc_dma_pointer,
 	.trigger	= psc_dma_trigger,
 	.hw_params	= psc_dma_hw_params,
 };

 static int psc_dma_new(struct snd_soc_pcm_runtime *rtd)
 {
 	struct snd_card *card = rtd->card->snd_card;
 	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, DRV_NAME);
 	struct snd_soc_dai *dai = rtd->cpu_dai;
 	struct snd_pcm *pcm = rtd->pcm;
 	size_t size = psc_dma_hardware.buffer_bytes_max;
 	int rc;

 	dev_dbg(component->dev, "psc_dma_new(card=%p, dai=%p, pcm=%p)\n",
 		card, dai, pcm);

 	rc = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
 	if (rc)
 		return rc;

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

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

 	return 0;

  capture_alloc_err:
 	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream)
 		snd_dma_free_pages(&pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream->dma_buffer);

  playback_alloc_err:
 	dev_err(card->dev, "Cannot allocate buffer(s)\n");

 	return -ENOMEM;
 }

 static void psc_dma_free(struct snd_pcm *pcm)
 {
 	struct snd_soc_pcm_runtime *rtd = pcm->private_data;
 	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, DRV_NAME);
 	struct snd_pcm_substream *substream;
 	int stream;

 	dev_dbg(component->dev, "psc_dma_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;
 		}
 	}
 }

 static const struct snd_soc_component_driver mpc5200_audio_dma_component = {
 	.name		= DRV_NAME,
 	.ops		= &psc_dma_ops,
 	.pcm_new	= &psc_dma_new,
 	.pcm_free	= &psc_dma_free,
 };

 int mpc5200_audio_dma_create(struct platform_device *op)
 {
 	phys_addr_t fifo;
 	struct psc_dma *psc_dma;
 	struct resource res;
 	int size, irq, rc;
 	const __be32 *prop;
 	void __iomem *regs;
 	int ret;

 	/* Fetch the registers and IRQ of the PSC */
 	irq = irq_of_parse_and_map(op->dev.of_node, 0);
 	if (of_address_to_resource(op->dev.of_node, 0, &res)) {
 		dev_err(&op->dev, "Missing reg property\n");
 		return -ENODEV;
 	}
 	regs = ioremap(res.start, resource_size(&res));
 	if (!regs) {
 		dev_err(&op->dev, "Could not map registers\n");
 		return -ENODEV;
 	}

 	/* Allocate and initialize the driver private data */
 	psc_dma = kzalloc(sizeof *psc_dma, GFP_KERNEL);
 	if (!psc_dma) {
 		ret = -ENOMEM;
 		goto out_unmap;
 	}

 	/* Get the PSC ID */
 	prop = of_get_property(op->dev.of_node, "cell-index", &size);
 	if (!prop || size < sizeof *prop) {
 		ret = -ENODEV;
 		goto out_free;
 	}

 	spin_lock_init(&psc_dma->lock);
 	mutex_init(&psc_dma->mutex);
 	psc_dma->id = be32_to_cpu(*prop);
 	psc_dma->irq = irq;
 	psc_dma->psc_regs = regs;
 	psc_dma->fifo_regs = regs + sizeof *psc_dma->psc_regs;
 	psc_dma->dev = &op->dev;
 	psc_dma->playback.psc_dma = psc_dma;
 	psc_dma->capture.psc_dma = psc_dma;
 	snprintf(psc_dma->name, sizeof psc_dma->name, "PSC%u", psc_dma->id);

 	/* Find the address of the fifo data registers and setup the
 	 * DMA tasks */
 	fifo = res.start + offsetof(struct mpc52xx_psc, buffer.buffer_32);
 	psc_dma->capture.bcom_task =
 		bcom_psc_gen_bd_rx_init(psc_dma->id, 10, fifo, 512);
 	psc_dma->playback.bcom_task =
 		bcom_psc_gen_bd_tx_init(psc_dma->id, 10, fifo);
 	if (!psc_dma->capture.bcom_task ||
 	    !psc_dma->playback.bcom_task) {
 		dev_err(&op->dev, "Could not allocate bestcomm tasks\n");
 		ret = -ENODEV;
 		goto out_free;
 	}

 	/* Disable all interrupts and reset the PSC */
 	out_be16(&psc_dma->psc_regs->isr_imr.imr, psc_dma->imr);
 	 /* reset receiver */
 	out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_RX);
 	 /* reset transmitter */
 	out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_TX);
 	 /* reset error */
 	out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_ERR_STAT);
 	 /* reset mode */
 	out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_SEL_MODE_REG_1);

 	/* Set up mode register;
 	 * First write: RxRdy (FIFO Alarm) generates rx FIFO irq
 	 * Second write: register Normal mode for non loopback
 	 */
 	out_8(&psc_dma->psc_regs->mode, 0);
 	out_8(&psc_dma->psc_regs->mode, 0);

 	/* Set the TX and RX fifo alarm thresholds */
 	out_be16(&psc_dma->fifo_regs->rfalarm, 0x100);
 	out_8(&psc_dma->fifo_regs->rfcntl, 0x4);
 	out_be16(&psc_dma->fifo_regs->tfalarm, 0x100);
 	out_8(&psc_dma->fifo_regs->tfcntl, 0x7);

 	/* Lookup the IRQ numbers */
 	psc_dma->playback.irq =
 		bcom_get_task_irq(psc_dma->playback.bcom_task);
 	psc_dma->capture.irq =
 		bcom_get_task_irq(psc_dma->capture.bcom_task);

 	rc = request_irq(psc_dma->irq, &psc_dma_status_irq, IRQF_SHARED,
 			 "psc-dma-status", psc_dma);
 	rc |= request_irq(psc_dma->capture.irq, &psc_dma_bcom_irq, IRQF_SHARED,
 			  "psc-dma-capture", &psc_dma->capture);
 	rc |= request_irq(psc_dma->playback.irq, &psc_dma_bcom_irq, IRQF_SHARED,
 			  "psc-dma-playback", &psc_dma->playback);
 	if (rc) {
 		ret = -ENODEV;
 		goto out_irq;
 	}

 	/* Save what we've done so it can be found again later */
 	dev_set_drvdata(&op->dev, psc_dma);

 	/* Tell the ASoC OF helpers about it */
 	return devm_snd_soc_register_component(&op->dev,
 					&mpc5200_audio_dma_component, NULL, 0);
 out_irq:
 	free_irq(psc_dma->irq, psc_dma);
 	free_irq(psc_dma->capture.irq, &psc_dma->capture);
 	free_irq(psc_dma->playback.irq, &psc_dma->playback);
 out_free:
 	kfree(psc_dma);
 out_unmap:
 	iounmap(regs);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(mpc5200_audio_dma_create);

 int mpc5200_audio_dma_destroy(struct platform_device *op)
 {
 	struct psc_dma *psc_dma = dev_get_drvdata(&op->dev);

 	dev_dbg(&op->dev, "mpc5200_audio_dma_destroy()\n");

 	bcom_gen_bd_rx_release(psc_dma->capture.bcom_task);
 	bcom_gen_bd_tx_release(psc_dma->playback.bcom_task);

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

 	iounmap(psc_dma->psc_regs);
 	kfree(psc_dma);
 	dev_set_drvdata(&op->dev, NULL);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(mpc5200_audio_dma_destroy);

 MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
 MODULE_DESCRIPTION("Freescale MPC5200 PSC in DMA mode ASoC Driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-only
	//
	// Freescale MPC5200 PSC DMA
	// ALSA SoC Platform driver
	//
	// Copyright (C) 2008 Secret Lab Technologies Ltd.
	// Copyright (C) 2009 Jon Smirl, Digispeaker

	#include <linux/module.h>
	#include <linux/of_device.h>
	#include <linux/dma-mapping.h>
	#include <linux/slab.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/of_platform.h>

	#include <sound/soc.h>

	#include <linux/fsl/bestcomm/bestcomm.h>
	#include <linux/fsl/bestcomm/gen_bd.h>
	#include <asm/mpc52xx_psc.h>

	#include "mpc5200_dma.h"

	#define DRV_NAME "mpc5200_dma"

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

	isr = in_be16(&regs->mpc52xx_psc_isr);

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

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

	out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);

	return IRQ_HANDLED;
	}

	/**
	* psc_dma_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_dma_bcom_enqueue_next_buffer(struct psc_dma_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->runtime->dma_addr + (s->period_next * s->period_bytes);
	bcom_submit_next_buffer(s->bcom_task, NULL);

	/* Update for next period */
	s->period_next = (s->period_next + 1) % s->runtime->periods;
	}

	/* Bestcomm DMA irq handler */
	static irqreturn_t psc_dma_bcom_irq(int irq, void *_psc_dma_stream)
	{
	struct psc_dma_stream *s = _psc_dma_stream;

	spin_lock(&s->psc_dma->lock);
	/* 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 = (s->period_current+1) % s->runtime->periods;
	s->period_count++;

	psc_dma_bcom_enqueue_next_buffer(s);
	}
	spin_unlock(&s->psc_dma->lock);

	/* 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;
	}

	static int psc_dma_hw_free(struct snd_pcm_substream *substream)
	{
	snd_pcm_set_runtime_buffer(substream, NULL);
	return 0;
	}

	/**
	* psc_dma_trigger: start and stop the DMA transfer.
	*
	* This function is called by ALSA to start, stop, pause, and resume the DMA
	* transfer of data.
	*/
	static int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(rtd->cpu_dai);
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct psc_dma_stream *s = to_psc_dma_stream(substream, psc_dma);
	struct mpc52xx_psc __iomem *regs = psc_dma->psc_regs;
	u16 imr;
	unsigned long flags;
	int i;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	dev_dbg(psc_dma->dev, "START: stream=%i fbits=%u ps=%u #p=%u\n",
	substream->pstr->stream, runtime->frame_bits,
	(int)runtime->period_size, runtime->periods);
	s->period_bytes = frames_to_bytes(runtime,
	runtime->period_size);
	s->period_next = 0;
	s->period_current = 0;
	s->active = 1;
	s->period_count = 0;
	s->runtime = runtime;

	/* Fill up the bestcomm bd queue and enable DMA.
	* This will begin filling the PSC's fifo.
	*/
	spin_lock_irqsave(&psc_dma->lock, flags);

	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);

	for (i = 0; i < runtime->periods; i++)
	if (!bcom_queue_full(s->bcom_task))
	psc_dma_bcom_enqueue_next_buffer(s);

	bcom_enable(s->bcom_task);
	spin_unlock_irqrestore(&psc_dma->lock, flags);

	out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);

	break;

	case SNDRV_PCM_TRIGGER_STOP:
	dev_dbg(psc_dma->dev, "STOP: stream=%i periods_count=%i\n",
	substream->pstr->stream, s->period_count);
	s->active = 0;

	spin_lock_irqsave(&psc_dma->lock, flags);
	bcom_disable(s->bcom_task);
	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);
	spin_unlock_irqrestore(&psc_dma->lock, flags);

	break;

	default:
	dev_dbg(psc_dma->dev, "unhandled trigger: stream=%i cmd=%i\n",
	substream->pstr->stream, cmd);
	return -EINVAL;
	}

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

	return 0;
	}


	/* ---------------------------------------------------------------------
	* 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_dma_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,
	.period_bytes_max = 1024 * 1024,
	.period_bytes_min = 32,
	.periods_min = 2,
	.periods_max = 256,
	.buffer_bytes_max = 2 * 1024 * 1024,
	.fifo_size = 512,
	};

	static int psc_dma_open(struct snd_pcm_substream *substream)
	{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(rtd->cpu_dai);
	struct psc_dma_stream *s;
	int rc;

	dev_dbg(psc_dma->dev, "psc_dma_open(substream=%p)\n", substream);

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

	snd_soc_set_runtime_hwparams(substream, &psc_dma_hardware);

	rc = snd_pcm_hw_constraint_integer(runtime,
	SNDRV_PCM_HW_PARAM_PERIODS);
	if (rc < 0) {
	dev_err(substream->pcm->card->dev, "invalid buffer size\n");
	return rc;
	}

	s->stream = substream;
	return 0;
	}

	static int psc_dma_close(struct snd_pcm_substream *substream)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(rtd->cpu_dai);
	struct psc_dma_stream *s;

	dev_dbg(psc_dma->dev, "psc_dma_close(substream=%p)\n", substream);

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

	if (!psc_dma->playback.active &&
	!psc_dma->capture.active) {

	/* Disable all interrupts and reset the PSC */
	out_be16(&psc_dma->psc_regs->isr_imr.imr, psc_dma->imr);
	out_8(&psc_dma->psc_regs->command, 4 << 4); /* reset error */
	}
	s->stream = NULL;
	return 0;
	}

	static snd_pcm_uframes_t
	psc_dma_pointer(struct snd_pcm_substream *substream)
	{
	struct snd_soc_pcm_runtime *rtd = substream->private_data;
	struct psc_dma *psc_dma = snd_soc_dai_get_drvdata(rtd->cpu_dai);
	struct psc_dma_stream *s;
	dma_addr_t count;

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

	count = s->period_current * s->period_bytes;

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

	static int
	psc_dma_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params)
	{
	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

	return 0;
	}

	static const struct snd_pcm_ops psc_dma_ops = {
	.open = psc_dma_open,
	.close = psc_dma_close,
	.hw_free = psc_dma_hw_free,
	.ioctl = snd_pcm_lib_ioctl,
	.pointer = psc_dma_pointer,
	.trigger = psc_dma_trigger,
	.hw_params = psc_dma_hw_params,
	};

	static int psc_dma_new(struct snd_soc_pcm_runtime *rtd)
	{
	struct snd_card *card = rtd->card->snd_card;
	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, DRV_NAME);
	struct snd_soc_dai *dai = rtd->cpu_dai;
	struct snd_pcm *pcm = rtd->pcm;
	size_t size = psc_dma_hardware.buffer_bytes_max;
	int rc;

	dev_dbg(component->dev, "psc_dma_new(card=%p, dai=%p, pcm=%p)\n",
	card, dai, pcm);

	rc = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
	if (rc)
	return rc;

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

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

	return 0;

	capture_alloc_err:
	if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream)
	snd_dma_free_pages(&pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream->dma_buffer);

	playback_alloc_err:
	dev_err(card->dev, "Cannot allocate buffer(s)\n");

	return -ENOMEM;
	}

	static void psc_dma_free(struct snd_pcm *pcm)
	{
	struct snd_soc_pcm_runtime *rtd = pcm->private_data;
	struct snd_soc_component *component = snd_soc_rtdcom_lookup(rtd, DRV_NAME);
	struct snd_pcm_substream *substream;
	int stream;

	dev_dbg(component->dev, "psc_dma_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;
	}
	}
	}

	static const struct snd_soc_component_driver mpc5200_audio_dma_component = {
	.name = DRV_NAME,
	.ops = &psc_dma_ops,
	.pcm_new = &psc_dma_new,
	.pcm_free = &psc_dma_free,
	};

	int mpc5200_audio_dma_create(struct platform_device *op)
	{
	phys_addr_t fifo;
	struct psc_dma *psc_dma;
	struct resource res;
	int size, irq, rc;
	const __be32 *prop;
	void __iomem *regs;
	int ret;

	/* Fetch the registers and IRQ of the PSC */
	irq = irq_of_parse_and_map(op->dev.of_node, 0);
	if (of_address_to_resource(op->dev.of_node, 0, &res)) {
	dev_err(&op->dev, "Missing reg property\n");
	return -ENODEV;
	}
	regs = ioremap(res.start, resource_size(&res));
	if (!regs) {
	dev_err(&op->dev, "Could not map registers\n");
	return -ENODEV;
	}

	/* Allocate and initialize the driver private data */
	psc_dma = kzalloc(sizeof *psc_dma, GFP_KERNEL);
	if (!psc_dma) {
	ret = -ENOMEM;
	goto out_unmap;
	}

	/* Get the PSC ID */
	prop = of_get_property(op->dev.of_node, "cell-index", &size);
	if (!prop \|\| size < sizeof *prop) {
	ret = -ENODEV;
	goto out_free;
	}

	spin_lock_init(&psc_dma->lock);
	mutex_init(&psc_dma->mutex);
	psc_dma->id = be32_to_cpu(*prop);
	psc_dma->irq = irq;
	psc_dma->psc_regs = regs;
	psc_dma->fifo_regs = regs + sizeof *psc_dma->psc_regs;
	psc_dma->dev = &op->dev;
	psc_dma->playback.psc_dma = psc_dma;
	psc_dma->capture.psc_dma = psc_dma;
	snprintf(psc_dma->name, sizeof psc_dma->name, "PSC%u", psc_dma->id);

	/* Find the address of the fifo data registers and setup the
	* DMA tasks */
	fifo = res.start + offsetof(struct mpc52xx_psc, buffer.buffer_32);
	psc_dma->capture.bcom_task =
	bcom_psc_gen_bd_rx_init(psc_dma->id, 10, fifo, 512);
	psc_dma->playback.bcom_task =
	bcom_psc_gen_bd_tx_init(psc_dma->id, 10, fifo);
	if (!psc_dma->capture.bcom_task \|\|
	!psc_dma->playback.bcom_task) {
	dev_err(&op->dev, "Could not allocate bestcomm tasks\n");
	ret = -ENODEV;
	goto out_free;
	}

	/* Disable all interrupts and reset the PSC */
	out_be16(&psc_dma->psc_regs->isr_imr.imr, psc_dma->imr);
	/* reset receiver */
	out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_RX);
	/* reset transmitter */
	out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_TX);
	/* reset error */
	out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_ERR_STAT);
	/* reset mode */
	out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_SEL_MODE_REG_1);

	/* Set up mode register;
	* First write: RxRdy (FIFO Alarm) generates rx FIFO irq
	* Second write: register Normal mode for non loopback
	*/
	out_8(&psc_dma->psc_regs->mode, 0);
	out_8(&psc_dma->psc_regs->mode, 0);

	/* Set the TX and RX fifo alarm thresholds */
	out_be16(&psc_dma->fifo_regs->rfalarm, 0x100);
	out_8(&psc_dma->fifo_regs->rfcntl, 0x4);
	out_be16(&psc_dma->fifo_regs->tfalarm, 0x100);
	out_8(&psc_dma->fifo_regs->tfcntl, 0x7);

	/* Lookup the IRQ numbers */
	psc_dma->playback.irq =
	bcom_get_task_irq(psc_dma->playback.bcom_task);
	psc_dma->capture.irq =
	bcom_get_task_irq(psc_dma->capture.bcom_task);

	rc = request_irq(psc_dma->irq, &psc_dma_status_irq, IRQF_SHARED,
	"psc-dma-status", psc_dma);
	rc \|= request_irq(psc_dma->capture.irq, &psc_dma_bcom_irq, IRQF_SHARED,
	"psc-dma-capture", &psc_dma->capture);
	rc \|= request_irq(psc_dma->playback.irq, &psc_dma_bcom_irq, IRQF_SHARED,
	"psc-dma-playback", &psc_dma->playback);
	if (rc) {
	ret = -ENODEV;
	goto out_irq;
	}

	/* Save what we've done so it can be found again later */
	dev_set_drvdata(&op->dev, psc_dma);

	/* Tell the ASoC OF helpers about it */
	return devm_snd_soc_register_component(&op->dev,
	&mpc5200_audio_dma_component, NULL, 0);
	out_irq:
	free_irq(psc_dma->irq, psc_dma);
	free_irq(psc_dma->capture.irq, &psc_dma->capture);
	free_irq(psc_dma->playback.irq, &psc_dma->playback);
	out_free:
	kfree(psc_dma);
	out_unmap:
	iounmap(regs);
	return ret;
	}
	EXPORT_SYMBOL_GPL(mpc5200_audio_dma_create);

	int mpc5200_audio_dma_destroy(struct platform_device *op)
	{
	struct psc_dma *psc_dma = dev_get_drvdata(&op->dev);

	dev_dbg(&op->dev, "mpc5200_audio_dma_destroy()\n");

	bcom_gen_bd_rx_release(psc_dma->capture.bcom_task);
	bcom_gen_bd_tx_release(psc_dma->playback.bcom_task);

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

	iounmap(psc_dma->psc_regs);
	kfree(psc_dma);
	dev_set_drvdata(&op->dev, NULL);

	return 0;
	}
	EXPORT_SYMBOL_GPL(mpc5200_audio_dma_destroy);

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