ASoC: Main rewite of the mpc5200 audio DMA code

Rewrite the mpc5200 audio DMA code to support both I2S and AC97.

Signed-off-by: Jon Smirl <jonsmirl@gmail.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 274 insertions, 168 deletions

diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c
index 685039213f0..efec33a1c5b 100644
--- a/sound/soc/fsl/mpc5200_dma.c
+++ b/sound/soc/fsl/mpc5200_dma.c
@@ -3,23 +3,13 @@
  * ALSA SoC Platform driver
  *
  * Copyright (C) 2008 Secret Lab Technologies Ltd.
+ * Copyright (C) 2009 Jon Smirl, Digispeaker
  */
 
-#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>
@@ -27,10 +17,6 @@
 
 #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
  */
@@ -50,7 +36,7 @@ static irqreturn_t psc_dma_status_irq(int irq, void *_psc_dma)
 	if (psc_dma->capture.active && (isr & MPC52xx_PSC_IMR_ORERR))
 		psc_dma->stats.overrun_count++;
 
-	out_8(&regs->command, 4 << 4);	/* reset the error status */
+	out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);
 
 	return IRQ_HANDLED;
 }
@@ -81,21 +67,36 @@ static void psc_dma_bcom_enqueue_next_buffer(struct psc_dma_stream *s)
 		s->period_next_pt = s->period_start;
 }
 
+static void psc_dma_bcom_enqueue_tx(struct psc_dma_stream *s)
+{
+	while (s->appl_ptr < s->runtime->control->appl_ptr) {
+
+		if (bcom_queue_full(s->bcom_task))
+			return;
+
+		s->appl_ptr += s->period_size;
+
+		psc_dma_bcom_enqueue_next_buffer(s);
+	}
+}
+
 /* Bestcomm DMA irq handler */
-static irqreturn_t psc_dma_bcom_irq(int irq, void *_psc_dma_stream)
+static irqreturn_t psc_dma_bcom_irq_tx(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_pt += s->period_bytes;
 		if (s->period_current_pt >= s->period_end)
 			s->period_current_pt = s->period_start;
-		psc_dma_bcom_enqueue_next_buffer(s);
-		bcom_enable(s->bcom_task);
 	}
+	psc_dma_bcom_enqueue_tx(s);
+	spin_unlock(&s->psc_dma->lock);
 
 	/* If the stream is active, then also inform the PCM middle layer
 	 * of the period finished event. */
@@ -105,49 +106,33 @@ static irqreturn_t psc_dma_bcom_irq(int irq, void *_psc_dma_stream)
 	return IRQ_HANDLED;
 }
 
-/**
- * psc_dma_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_dma_startup(struct snd_pcm_substream *substream,
-			   struct snd_soc_dai *dai)
+static irqreturn_t psc_dma_bcom_irq_rx(int irq, void *_psc_dma_stream)
 {
-	struct snd_soc_pcm_runtime *rtd = substream->private_data;
-	struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
-	int rc;
+	struct psc_dma_stream *s = _psc_dma_stream;
 
-	dev_dbg(psc_dma->dev, "psc_dma_startup(substream=%p)\n", substream);
+	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);
 
-	if (!psc_dma->playback.active &&
-	    !psc_dma->capture.active) {
-		/* Setup the IRQs */
-		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) {
-			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);
-			return -ENODEV;
-		}
+		s->period_current_pt += s->period_bytes;
+		if (s->period_current_pt >= s->period_end)
+			s->period_current_pt = s->period_start;
+
+		psc_dma_bcom_enqueue_next_buffer(s);
 	}
+	spin_unlock(&s->psc_dma->lock);
 
-	return 0;
+	/* 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;
 }
 
-int psc_dma_hw_free(struct snd_pcm_substream *substream,
-			   struct snd_soc_dai *dai)
+static int psc_dma_hw_free(struct snd_pcm_substream *substream)
 {
 	snd_pcm_set_runtime_buffer(substream, NULL);
 	return 0;
@@ -159,8 +144,7 @@ int psc_dma_hw_free(struct snd_pcm_substream *substream,
  * This function is called by ALSA to start, stop, pause, and resume the DMA
  * transfer of data.
  */
-int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd,
-			   struct snd_soc_dai *dai)
+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 = rtd->dai->cpu_dai->private_data;
@@ -168,8 +152,8 @@ int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd,
 	struct psc_dma_stream *s;
 	struct mpc52xx_psc __iomem *regs = psc_dma->psc_regs;
 	u16 imr;
-	u8 psc_cmd;
 	unsigned long flags;
+	int i;
 
 	if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
 		s = &psc_dma->capture;
@@ -189,68 +173,48 @@ int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd,
 				(s->period_bytes * runtime->periods);
 		s->period_next_pt = s->period_start;
 		s->period_current_pt = s->period_start;
+		s->period_size = runtime->period_size;
 		s->active = 1;
 
-		/* First; reset everything */
+		/* track appl_ptr so that we have a better chance of detecting
+		 * end of stream and not over running it.
+		 */
+		s->runtime = runtime;
+		s->appl_ptr = s->runtime->control->appl_ptr -
+				(runtime->period_size * runtime->periods);
+
+		/* 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) {
-			out_8(&regs->command, MPC52xx_PSC_RST_RX);
-			out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);
+			bcom_gen_bd_rx_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);
 		} else {
-			out_8(&regs->command, MPC52xx_PSC_RST_TX);
-			out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);
+			bcom_gen_bd_tx_reset(s->bcom_task);
+			psc_dma_bcom_enqueue_tx(s);
 		}
 
-		/* 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_dma_bcom_enqueue_next_buffer(s);
 		bcom_enable(s->bcom_task);
-
-		/* Due to errata in the dma mode; need to line up enabling
-		 * the transmitter with a transition on the frame sync
-		 * line */
-
-		spin_lock_irqsave(&psc_dma->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_dma->lock, flags);
 
+		out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);
+
 		break;
 
 	case SNDRV_PCM_TRIGGER_STOP:
-		/* Turn off the PSC */
 		s->active = 0;
-		if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) {
-			if (!psc_dma->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_dma->capture.active)
-				out_8(&regs->command, 2 << 4);	/* reset rx */
-		}
 
+		spin_lock_irqsave(&psc_dma->lock, flags);
 		bcom_disable(s->bcom_task);
-		while (!bcom_queue_empty(s->bcom_task))
-			bcom_retrieve_buffer(s->bcom_task, NULL, NULL);
+		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;
 
@@ -265,44 +229,11 @@ int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd,
 		imr |= MPC52xx_PSC_IMR_TXEMP;
 	if (psc_dma->capture.active)
 		imr |= MPC52xx_PSC_IMR_ORERR;
-	out_be16(&regs->isr_imr.imr, imr);
+	out_be16(&regs->isr_imr.imr, psc_dma->imr | imr);
 
 	return 0;
 }
 
-/**
- * psc_dma_shutdown: shutdown the data transfer on a stream
- *
- * Shutdown the PSC if there are no other substreams open.
- */
-void psc_dma_shutdown(struct snd_pcm_substream *substream,
-			     struct snd_soc_dai *dai)
-{
-	struct snd_soc_pcm_runtime *rtd = substream->private_data;
-	struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
-
-	dev_dbg(psc_dma->dev, "psc_dma_shutdown(substream=%p)\n", substream);
-
-	/*
-	 * If this is the last active substream, disable the PSC and release
-	 * the IRQ.
-	 */
-	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, 0);
-		out_8(&psc_dma->psc_regs->command, 3 << 4); /* reset tx */
-		out_8(&psc_dma->psc_regs->command, 2 << 4); /* reset rx */
-		out_8(&psc_dma->psc_regs->command, 1 << 4); /* reset mode */
-		out_8(&psc_dma->psc_regs->command, 4 << 4); /* reset error */
-
-		/* 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);
-	}
-}
 
 /* ---------------------------------------------------------------------
  * The PSC DMA 'ASoC platform' driver
@@ -312,62 +243,78 @@ void psc_dma_shutdown(struct snd_pcm_substream *substream,
  * interaction with the attached codec
  */
 
-static const struct snd_pcm_hardware psc_dma_pcm_hardware = {
+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,
+		SNDRV_PCM_FMTBIT_S24_BE | SNDRV_PCM_FMTBIT_S32_BE,
 	.rate_min = 8000,
 	.rate_max = 48000,
-	.channels_min = 2,
+	.channels_min = 1,
 	.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,
+	.fifo_size		= 512,
 };
 
-static int psc_dma_pcm_open(struct snd_pcm_substream *substream)
+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 = rtd->dai->cpu_dai->private_data;
 	struct psc_dma_stream *s;
+	int rc;
 
-	dev_dbg(psc_dma->dev, "psc_dma_pcm_open(substream=%p)\n", substream);
+	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_pcm_hardware);
+	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_pcm_close(struct snd_pcm_substream *substream)
+static int psc_dma_close(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
 	struct psc_dma_stream *s;
 
-	dev_dbg(psc_dma->dev, "psc_dma_pcm_close(substream=%p)\n", substream);
+	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_pcm_pointer(struct snd_pcm_substream *substream)
+psc_dma_pointer(struct snd_pcm_substream *substream)
 {
 	struct snd_soc_pcm_runtime *rtd = substream->private_data;
 	struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
@@ -384,60 +331,78 @@ psc_dma_pcm_pointer(struct snd_pcm_substream *substream)
 	return bytes_to_frames(substream->runtime, count);
 }
 
-static struct snd_pcm_ops psc_dma_pcm_ops = {
-	.open		= psc_dma_pcm_open,
-	.close		= psc_dma_pcm_close,
+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 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_pcm_pointer,
+	.pointer	= psc_dma_pointer,
+	.trigger	= psc_dma_trigger,
+	.hw_params	= psc_dma_hw_params,
 };
 
-static u64 psc_dma_pcm_dmamask = 0xffffffff;
-static int psc_dma_pcm_new(struct snd_card *card, struct snd_soc_dai *dai,
+static u64 psc_dma_dmamask = 0xffffffff;
+static int psc_dma_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_dma_pcm_hardware.buffer_bytes_max;
+	struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
+	size_t size = psc_dma_hardware.buffer_bytes_max;
 	int rc = 0;
 
-	dev_dbg(rtd->socdev->dev, "psc_dma_pcm_new(card=%p, dai=%p, pcm=%p)\n",
+	dev_dbg(rtd->socdev->dev, "psc_dma_new(card=%p, dai=%p, pcm=%p)\n",
 		card, dai, pcm);
 
 	if (!card->dev->dma_mask)
-		card->dev->dma_mask = &psc_dma_pcm_dmamask;
+		card->dev->dma_mask = &psc_dma_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);
+		rc = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->card->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);
+		rc = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->card->dev,
+				size, &pcm->streams[1].substream->dma_buffer);
 		if (rc)
 			goto capture_alloc_err;
 	}
 
+	if (rtd->socdev->card->codec->ac97)
+		rtd->socdev->card->codec->ac97->private_data = psc_dma;
+
 	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_dma_pcm_free(struct snd_pcm *pcm)
+static void psc_dma_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_dma_pcm_free(pcm=%p)\n", pcm);
+	dev_dbg(rtd->socdev->dev, "psc_dma_free(pcm=%p)\n", pcm);
 
 	for (stream = 0; stream < 2; stream++) {
 		substream = pcm->streams[stream].substream;
@@ -449,10 +414,151 @@ static void psc_dma_pcm_free(struct snd_pcm *pcm)
 	}
 }
 
-struct snd_soc_platform psc_dma_pcm_soc_platform = {
+struct snd_soc_platform mpc5200_audio_dma_platform = {
 	.name		= "mpc5200-psc-audio",
-	.pcm_ops	= &psc_dma_pcm_ops,
-	.pcm_new	= &psc_dma_pcm_new,
-	.pcm_free	= &psc_dma_pcm_free,
+	.pcm_ops	= &psc_dma_ops,
+	.pcm_new	= &psc_dma_new,
+	.pcm_free	= &psc_dma_free,
 };
+EXPORT_SYMBOL_GPL(mpc5200_audio_dma_platform);
+
+int mpc5200_audio_dma_create(struct of_device *op)
+{
+	phys_addr_t fifo;
+	struct psc_dma *psc_dma;
+	struct resource res;
+	int size, irq, rc;
+	const __be32 *prop;
+	void __iomem *regs;
+
+	/* Fetch the registers and IRQ of the PSC */
+	irq = irq_of_parse_and_map(op->node, 0);
+	if (of_address_to_resource(op->node, 0, &res)) {
+		dev_err(&op->dev, "Missing reg property\n");
+		return -ENODEV;
+	}
+	regs = ioremap(res.start, 1 + res.end - res.start);
+	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) {
+		iounmap(regs);
+		return -ENOMEM;
+	}
+
+	/* Get the PSC ID */
+	prop = of_get_property(op->node, "cell-index", &size);
+	if (!prop || size < sizeof *prop)
+		return -ENODEV;
+
+	spin_lock_init(&psc_dma->lock);
+	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");
+		iounmap(regs);
+		kfree(psc_dma);
+		return -ENODEV;
+	}
+
+	/* 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_rx, IRQF_SHARED,
+			  "psc-dma-capture", &psc_dma->capture);
+	rc |= request_irq(psc_dma->playback.irq,
+			  &psc_dma_bcom_irq_tx, IRQF_SHARED,
+			  "psc-dma-playback", &psc_dma->playback);
+	if (rc) {
+		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);
+		return -ENODEV;
+	}
 
+	/* 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 snd_soc_register_platform(&mpc5200_audio_dma_platform);
+}
+EXPORT_SYMBOL_GPL(mpc5200_audio_dma_create);
+
+int mpc5200_audio_dma_destroy(struct of_device *op)
+{
+	struct psc_dma *psc_dma = dev_get_drvdata(&op->dev);
+
+	dev_dbg(&op->dev, "mpc5200_audio_dma_destroy()\n");
+
+	snd_soc_unregister_platform(&mpc5200_audio_dma_platform);
+
+	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");