ALSA: ASoC: Add mpc5200-psc I2S driver

This is an I2S bus driver for the MPC5200 PSC device.  It depends on the
soc-of helper functions to match a PSC device with a codec based on data
in the device tree.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

3 files changed, 893 insertions, 0 deletions

diff --git a/sound/soc/fsl/Kconfig b/sound/soc/fsl/Kconfig
index 398f00208678..bba9546ba5f5 100644
--- a/sound/soc/fsl/Kconfig
+++ b/sound/soc/fsl/Kconfig
@@ -17,3 +17,10 @@ config SND_SOC_MPC8610_HPCD
 	default y if MPC8610_HPCD
 	help
 	  Say Y if you want to enable audio on the Freescale MPC8610 HPCD.
+
+config SND_SOC_MPC5200_I2S
+	tristate "Freescale MPC5200 PSC in I2S mode driver"
+	select SND_SOC_OF_SIMPLE
+	depends on SND_SOC && PPC_MPC52xx
+	help
+	  Say Y here to support the MPC5200 PSCs in I2S mode.
diff --git a/sound/soc/fsl/Makefile b/sound/soc/fsl/Makefile
index aa2100b41146..035da4afec34 100644
--- a/sound/soc/fsl/Makefile
+++ b/sound/soc/fsl/Makefile
@@ -7,3 +7,5 @@ obj-$(CONFIG_SND_SOC_MPC8610_HPCD) += mpc8610_hpcd.o
 # MPC8610 Platform Support
 obj-$(CONFIG_SND_SOC_MPC8610) += fsl_ssi.o fsl_dma.o
 
+obj-$(CONFIG_SND_SOC_MPC5200_I2S) += mpc5200_psc_i2s.o
+
diff --git a/sound/soc/fsl/mpc5200_psc_i2s.c b/sound/soc/fsl/mpc5200_psc_i2s.c
new file mode 100644
index 000000000000..86923299bc10
--- /dev/null
+++ b/sound/soc/fsl/mpc5200_psc_i2s.c
@@ -0,0 +1,884 @@
+/*
+ * Freescale MPC5200 PSC in I2S mode
+ * ALSA SoC Digital Audio Interface (DAI) 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>
+
+MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
+MODULE_DESCRIPTION("Freescale MPC5200 PSC in I2S mode ASoC Driver");
+MODULE_LICENSE("GPL");
+
+/**
+ * PSC_I2S_RATES: sample rates supported by the I2S
+ *
+ * This driver currently only supports the PSC running in I2S slave mode,
+ * which means the codec determines the sample rate.  Therefore, we tell
+ * ALSA that we support all rates and let the codec driver decide what rates
+ * are really supported.
+ */
+#define PSC_I2S_RATES (SNDRV_PCM_RATE_5512 | SNDRV_PCM_RATE_8000_192000 | \
+			SNDRV_PCM_RATE_CONTINUOUS)
+
+/**
+ * PSC_I2S_FORMATS: audio formats supported by the PSC I2S mode
+ */
+#define PSC_I2S_FORMATS (SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_BE | \
+			 SNDRV_PCM_FMTBIT_S24_BE | SNDRV_PCM_FMTBIT_S24_BE | \
+			 SNDRV_PCM_FMTBIT_S32_BE)
+
+/**
+ * psc_i2s_stream - Data specific to a single stream (playback or capture)
+ * @active:		flag indicating if the stream is active
+ * @psc_i2s:		pointer back to parent psc_i2s data structure
+ * @bcom_task:		bestcomm task structure
+ * @irq:		irq number for bestcomm task
+ * @period_start:	physical address of start of DMA region
+ * @period_end:		physical address of end of DMA region
+ * @period_next_pt:	physical address of next DMA buffer to enqueue
+ * @period_bytes:	size of DMA period in bytes
+ */
+struct psc_i2s_stream {
+	int active;
+	struct psc_i2s *psc_i2s;
+	struct bcom_task *bcom_task;
+	int irq;
+	struct snd_pcm_substream *stream;
+	dma_addr_t period_start;
+	dma_addr_t period_end;
+	dma_addr_t period_next_pt;
+	dma_addr_t period_current_pt;
+	int period_bytes;
+};
+
+/**
+ * psc_i2s - Private driver data
+ * @name: short name for this device ("PSC0", "PSC1", etc)
+ * @psc_regs: pointer to the PSC's registers
+ * @fifo_regs: pointer to the PSC's FIFO registers
+ * @irq: IRQ of this PSC
+ * @dev: struct device pointer
+ * @dai: the CPU DAI for this device
+ * @sicr: Base value used in serial interface control register; mode is ORed
+ *        with this value.
+ * @playback: Playback stream context data
+ * @capture: Capture stream context data
+ */
+struct psc_i2s {
+	char name[32];
+	struct mpc52xx_psc __iomem *psc_regs;
+	struct mpc52xx_psc_fifo __iomem *fifo_regs;
+	unsigned int irq;
+	struct device *dev;
+	struct snd_soc_dai dai;
+	spinlock_t lock;
+	u32 sicr;
+
+	/* per-stream data */
+	struct psc_i2s_stream playback;
+	struct psc_i2s_stream capture;
+
+	/* Statistics */
+	struct {
+		int overrun_count;
+		int underrun_count;
+	} stats;
+};
+
+/*
+ * 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.
+ */
+static int psc_i2s_startup(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;
+	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;
+}
+
+static int psc_i2s_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *params)
+{
+	struct snd_soc_pcm_runtime *rtd = substream->private_data;
+	struct psc_i2s *psc_i2s = rtd->dai->cpu_dai->private_data;
+	u32 mode;
+
+	dev_dbg(psc_i2s->dev, "%s(substream=%p) p_size=%i p_bytes=%i"
+		" periods=%i buffer_size=%i  buffer_bytes=%i\n",
+		__func__, substream, params_period_size(params),
+		params_period_bytes(params), params_periods(params),
+		params_buffer_size(params), params_buffer_bytes(params));
+
+	switch (params_format(params)) {
+	case SNDRV_PCM_FORMAT_S8:
+		mode = MPC52xx_PSC_SICR_SIM_CODEC_8;
+		break;
+	case SNDRV_PCM_FORMAT_S16_BE:
+		mode = MPC52xx_PSC_SICR_SIM_CODEC_16;
+		break;
+	case SNDRV_PCM_FORMAT_S24_BE:
+		mode = MPC52xx_PSC_SICR_SIM_CODEC_24;
+		break;
+	case SNDRV_PCM_FORMAT_S32_BE:
+		mode = MPC52xx_PSC_SICR_SIM_CODEC_32;
+		break;
+	default:
+		dev_dbg(psc_i2s->dev, "invalid format\n");
+		return -EINVAL;
+	}
+	out_be32(&psc_i2s->psc_regs->sicr, psc_i2s->sicr | mode);
+
+	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
+
+	return 0;
+}
+
+static int psc_i2s_hw_free(struct snd_pcm_substream *substream)
+{
+	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.
+ */
+static int psc_i2s_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+	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;
+	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.
+ */
+static void psc_i2s_shutdown(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;
+
+	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);
+	}
+}
+
+/**
+ * psc_i2s_set_sysclk: set the clock frequency and direction
+ *
+ * This function is called by the machine driver to tell us what the clock
+ * frequency and direction are.
+ *
+ * Currently, we only support operating as a clock slave (SND_SOC_CLOCK_IN),
+ * and we don't care about the frequency.  Return an error if the direction
+ * is not SND_SOC_CLOCK_IN.
+ *
+ * @clk_id: reserved, should be zero
+ * @freq: the frequency of the given clock ID, currently ignored
+ * @dir: SND_SOC_CLOCK_IN (clock slave) or SND_SOC_CLOCK_OUT (clock master)
+ */
+static int psc_i2s_set_sysclk(struct snd_soc_dai *cpu_dai,
+			      int clk_id, unsigned int freq, int dir)
+{
+	struct psc_i2s *psc_i2s = cpu_dai->private_data;
+	dev_dbg(psc_i2s->dev, "psc_i2s_set_sysclk(cpu_dai=%p, dir=%i)\n",
+				cpu_dai, dir);
+	return (dir == SND_SOC_CLOCK_IN) ? 0 : -EINVAL;
+}
+
+/**
+ * psc_i2s_set_fmt: set the serial format.
+ *
+ * This function is called by the machine driver to tell us what serial
+ * format to use.
+ *
+ * This driver only supports I2S mode.  Return an error if the format is
+ * not SND_SOC_DAIFMT_I2S.
+ *
+ * @format: one of SND_SOC_DAIFMT_xxx
+ */
+static int psc_i2s_set_fmt(struct snd_soc_dai *cpu_dai, unsigned int format)
+{
+	struct psc_i2s *psc_i2s = cpu_dai->private_data;
+	dev_dbg(psc_i2s->dev, "psc_i2s_set_fmt(cpu_dai=%p, format=%i)\n",
+				cpu_dai, format);
+	return (format == SND_SOC_DAIFMT_I2S) ? 0 : -EINVAL;
+}
+
+/* ---------------------------------------------------------------------
+ * ALSA SoC Bindings
+ *
+ * - Digital Audio Interface (DAI) template
+ * - create/destroy dai hooks
+ */
+
+/**
+ * psc_i2s_dai_template: template CPU Digital Audio Interface
+ */
+static struct snd_soc_dai psc_i2s_dai_template = {
+	.type = SND_SOC_DAI_I2S,
+	.playback = {
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = PSC_I2S_RATES,
+		.formats = PSC_I2S_FORMATS,
+	},
+	.capture = {
+		.channels_min = 2,
+		.channels_max = 2,
+		.rates = PSC_I2S_RATES,
+		.formats = PSC_I2S_FORMATS,
+	},
+	.ops = {
+		.startup = psc_i2s_startup,
+		.hw_params = psc_i2s_hw_params,
+		.hw_free = psc_i2s_hw_free,
+		.shutdown = psc_i2s_shutdown,
+		.trigger = psc_i2s_trigger,
+	},
+	.dai_ops = {
+		.set_sysclk = psc_i2s_set_sysclk,
+		.set_fmt = psc_i2s_set_fmt,
+	},
+};
+
+/* ---------------------------------------------------------------------
+ * The PSC I2S '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,
+	.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,
+};
+
+/* ---------------------------------------------------------------------
+ * Sysfs attributes for debugging
+ */
+
+static ssize_t psc_i2s_status_show(struct device *dev,
+			   struct device_attribute *attr, char *buf)
+{
+	struct psc_i2s *psc_i2s = dev_get_drvdata(dev);
+
+	return sprintf(buf, "status=%.4x sicr=%.8x rfnum=%i rfstat=0x%.4x "
+			"tfnum=%i tfstat=0x%.4x\n",
+			in_be16(&psc_i2s->psc_regs->sr_csr.status),
+			in_be32(&psc_i2s->psc_regs->sicr),
+			in_be16(&psc_i2s->fifo_regs->rfnum) & 0x1ff,
+			in_be16(&psc_i2s->fifo_regs->rfstat),
+			in_be16(&psc_i2s->fifo_regs->tfnum) & 0x1ff,
+			in_be16(&psc_i2s->fifo_regs->tfstat));
+}
+
+static int *psc_i2s_get_stat_attr(struct psc_i2s *psc_i2s, const char *name)
+{
+	if (strcmp(name, "playback_underrun") == 0)
+		return &psc_i2s->stats.underrun_count;
+	if (strcmp(name, "capture_overrun") == 0)
+		return &psc_i2s->stats.overrun_count;
+
+	return NULL;
+}
+
+static ssize_t psc_i2s_stat_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	struct psc_i2s *psc_i2s = dev_get_drvdata(dev);
+	int *attrib;
+
+	attrib = psc_i2s_get_stat_attr(psc_i2s, attr->attr.name);
+	if (!attrib)
+		return 0;
+
+	return sprintf(buf, "%i\n", *attrib);
+}
+
+static ssize_t psc_i2s_stat_store(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t count)
+{
+	struct psc_i2s *psc_i2s = dev_get_drvdata(dev);
+	int *attrib;
+
+	attrib = psc_i2s_get_stat_attr(psc_i2s, attr->attr.name);
+	if (!attrib)
+		return 0;
+
+	*attrib = simple_strtoul(buf, NULL, 0);
+	return count;
+}
+
+DEVICE_ATTR(status, 0644, psc_i2s_status_show, NULL);
+DEVICE_ATTR(playback_underrun, 0644, psc_i2s_stat_show, psc_i2s_stat_store);
+DEVICE_ATTR(capture_overrun, 0644, psc_i2s_stat_show, psc_i2s_stat_store);
+
+/* ---------------------------------------------------------------------
+ * OF platform bus binding code:
+ * - Probe/remove operations
+ * - OF device match table
+ */
+static int __devinit psc_i2s_of_probe(struct of_device *op,
+				      const struct of_device_id *match)
+{
+	phys_addr_t fifo;
+	struct psc_i2s *psc_i2s;
+	struct resource res;
+	int size, psc_id, irq, rc;
+	const __be32 *prop;
+	void __iomem *regs;
+
+	dev_dbg(&op->dev, "probing psc i2s device\n");
+
+	/* Get the PSC ID */
+	prop = of_get_property(op->node, "cell-index", &size);
+	if (!prop || size < sizeof *prop)
+		return -ENODEV;
+	psc_id = be32_to_cpu(*prop);
+
+	/* 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_i2s = kzalloc(sizeof *psc_i2s, GFP_KERNEL);
+	if (!psc_i2s) {
+		iounmap(regs);
+		return -ENOMEM;
+	}
+	spin_lock_init(&psc_i2s->lock);
+	psc_i2s->irq = irq;
+	psc_i2s->psc_regs = regs;
+	psc_i2s->fifo_regs = regs + sizeof *psc_i2s->psc_regs;
+	psc_i2s->dev = &op->dev;
+	psc_i2s->playback.psc_i2s = psc_i2s;
+	psc_i2s->capture.psc_i2s = psc_i2s;
+	snprintf(psc_i2s->name, sizeof psc_i2s->name, "PSC%u", psc_id+1);
+
+	/* Fill out the CPU DAI structure */
+	memcpy(&psc_i2s->dai, &psc_i2s_dai_template, sizeof psc_i2s->dai);
+	psc_i2s->dai.private_data = psc_i2s;
+	psc_i2s->dai.name = psc_i2s->name;
+	psc_i2s->dai.id = psc_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_i2s->capture.bcom_task =
+		bcom_psc_gen_bd_rx_init(psc_id, 10, fifo, 512);
+	psc_i2s->playback.bcom_task =
+		bcom_psc_gen_bd_tx_init(psc_id, 10, fifo);
+	if (!psc_i2s->capture.bcom_task ||
+	    !psc_i2s->playback.bcom_task) {
+		dev_err(&op->dev, "Could not allocate bestcomm tasks\n");
+		iounmap(regs);
+		kfree(psc_i2s);
+		return -ENODEV;
+	}
+
+	/* 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 transmitter */
+	out_8(&psc_i2s->psc_regs->command, 2 << 4); /* reset receiver */
+	out_8(&psc_i2s->psc_regs->command, 1 << 4); /* reset mode */
+	out_8(&psc_i2s->psc_regs->command, 4 << 4); /* reset error */
+
+	/* Configure the serial interface mode; defaulting to CODEC8 mode */
+	psc_i2s->sicr = MPC52xx_PSC_SICR_DTS1 | MPC52xx_PSC_SICR_I2S |
+			MPC52xx_PSC_SICR_CLKPOL;
+	if (of_get_property(op->node, "fsl,cellslave", NULL))
+		psc_i2s->sicr |= MPC52xx_PSC_SICR_CELLSLAVE |
+				 MPC52xx_PSC_SICR_GENCLK;
+	out_be32(&psc_i2s->psc_regs->sicr,
+		 psc_i2s->sicr | MPC52xx_PSC_SICR_SIM_CODEC_8);
+
+	/* Check for the codec handle.  If it is not present then we
+	 * are done */
+	if (!of_get_property(op->node, "codec-handle", NULL))
+		return 0;
+
+	/* Set up mode register;
+	 * First write: RxRdy (FIFO Alarm) generates rx FIFO irq
+	 * Second write: register Normal mode for non loopback
+	 */
+	out_8(&psc_i2s->psc_regs->mode, 0);
+	out_8(&psc_i2s->psc_regs->mode, 0);
+
+	/* Set the TX and RX fifo alarm thresholds */
+	out_be16(&psc_i2s->fifo_regs->rfalarm, 0x100);
+	out_8(&psc_i2s->fifo_regs->rfcntl, 0x4);
+	out_be16(&psc_i2s->fifo_regs->tfalarm, 0x100);
+	out_8(&psc_i2s->fifo_regs->tfcntl, 0x7);
+
+	/* Lookup the IRQ numbers */
+	psc_i2s->playback.irq =
+		bcom_get_task_irq(psc_i2s->playback.bcom_task);
+	psc_i2s->capture.irq =
+		bcom_get_task_irq(psc_i2s->capture.bcom_task);
+
+	/* Save what we've done so it can be found again later */
+	dev_set_drvdata(&op->dev, psc_i2s);
+
+	/* Register the SYSFS files */
+	rc = device_create_file(psc_i2s->dev, &dev_attr_status);
+	rc = device_create_file(psc_i2s->dev, &dev_attr_capture_overrun);
+	rc = device_create_file(psc_i2s->dev, &dev_attr_playback_underrun);
+	if (rc)
+		dev_info(psc_i2s->dev, "error creating sysfs files\n");
+
+	/* Tell the ASoC OF helpers about it */
+	of_snd_soc_register_platform(&psc_i2s_pcm_soc_platform, op->node,
+				     &psc_i2s->dai);
+
+	return 0;
+}
+
+static int __devexit psc_i2s_of_remove(struct of_device *op)
+{
+	struct psc_i2s *psc_i2s = dev_get_drvdata(&op->dev);
+
+	dev_dbg(&op->dev, "psc_i2s_remove()\n");
+
+	bcom_gen_bd_rx_release(psc_i2s->capture.bcom_task);
+	bcom_gen_bd_tx_release(psc_i2s->playback.bcom_task);
+
+	iounmap(psc_i2s->psc_regs);
+	iounmap(psc_i2s->fifo_regs);
+	kfree(psc_i2s);
+	dev_set_drvdata(&op->dev, NULL);
+
+	return 0;
+}
+
+/* Match table for of_platform binding */
+static struct of_device_id psc_i2s_match[] __devinitdata = {
+	{ .compatible = "fsl,mpc5200-psc-i2s", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, psc_i2s_match);
+
+static struct of_platform_driver psc_i2s_driver = {
+	.match_table = psc_i2s_match,
+	.probe = psc_i2s_of_probe,
+	.remove = __devexit_p(psc_i2s_of_remove),
+	.driver = {
+		.name = "mpc5200-psc-i2s",
+		.owner = THIS_MODULE,
+	},
+};
+
+/* ---------------------------------------------------------------------
+ * Module setup and teardown; simply register the of_platform driver
+ * for the PSC in I2S mode.
+ */
+static int __init psc_i2s_init(void)
+{
+	return of_register_platform_driver(&psc_i2s_driver);
+}
+module_init(psc_i2s_init);
+
+static void __exit psc_i2s_exit(void)
+{
+	of_unregister_platform_driver(&psc_i2s_driver);
+}
+module_exit(psc_i2s_exit);
+
+