[ALSA] Add ARM PXA2xx AC97 driver

Documentation,ARM,/arm/Makefile,ARM PXA2XX driver
Added ARM PXA2xx AC97 driver by Nicolas Pitre
(moved from alsa-driver tree).
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/alsa/ALSA-Configuration.txt

@@ -1059,6 +1059,13 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
 
     The power-management is supported.
 
+  Module snd-pxa2xx-ac97 (on arm only)
+  ------------------------------------
+
+    Module for AC97 driver for the Intel PXA2xx chip
+
+    For ARM architecture only.
+
   Module snd-rme32
   ----------------
 

sound/arm/Kconfig

@@ -20,5 +20,17 @@ config SND_ARMAACI
 	select SND_PCM
 	select SND_AC97_CODEC
 
-endmenu
+config SND_PXA2XX_PCM
+	tristate
+	select SND_PCM
+
+config SND_PXA2XX_AC97
+	tristate "AC97 driver for the Intel PXA2xx chip"
+	depends on ARCH_PXA && SND
+	select SND_PXA2XX_PCM
+	select SND_AC97_CODEC
+	help
+	  Say Y or M if you want to support any AC97 codec attached to
+	  the PXA2xx AC97 interface.
 
+endmenu

sound/arm/Makefile

@@ -3,9 +3,11 @@
 #
 
 snd-sa11xx-uda1341-objs := sa11xx-uda1341.o
+snd-aaci-objs			:= aaci.o devdma.o
+snd-pxa2xx-pcm-objs := pxa2xx-pcm.o
+snd-pxa2xx-ac97-objs := pxa2xx-ac97.o
 
-# Toplevel Module Dependency
 obj-$(CONFIG_SND_SA11XX_UDA1341) += snd-sa11xx-uda1341.o 
-
 obj-$(CONFIG_SND_ARMAACI)	+= snd-aaci.o
-snd-aaci-objs			:= aaci.o devdma.o
+obj-$(CONFIG_SND_PXA2XX_PCM) += snd-pxa2xx-pcm.o
+obj-$(CONFIG_SND_PXA2XX_AC97) += snd-pxa2xx-ac97.o

sound/arm/pxa2xx-ac97.c

+/*
+ * linux/sound/pxa2xx-ac97.c -- AC97 support for the Intel PXA2xx chip.
+ *
+ * Author:	Nicolas Pitre
+ * Created:	Dec 02, 2004
+ * Copyright:	MontaVista Software Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include <linux/delay.h>
+
+#include <sound/driver.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/ac97_codec.h>
+#include <sound/initval.h>
+
+#include <asm/irq.h>
+#include <asm/semaphore.h>
+#include <asm/hardware.h>
+#include <asm/arch/pxa-regs.h>
+#include <asm/arch/audio.h>
+
+#include "pxa2xx-pcm.h"
+
+
+static DECLARE_MUTEX(car_mutex);
+static DECLARE_WAIT_QUEUE_HEAD(gsr_wq);
+static volatile long gsr_bits;
+
+static unsigned short pxa2xx_ac97_read(ac97_t *ac97, unsigned short reg)
+{
+	unsigned short val = -1;
+	volatile u32 *reg_addr;
+
+	down(&car_mutex);
+	if (CAR & CAR_CAIP) {
+		printk(KERN_CRIT"%s: CAR_CAIP already set\n", __FUNCTION__);
+		goto out;
+	}
+
+	/* set up primary or secondary codec space */
+	reg_addr = (ac97->num & 1) ? &SAC_REG_BASE : &PAC_REG_BASE;
+	reg_addr += (reg >> 1);
+
+	/* start read access across the ac97 link */
+	gsr_bits = 0;
+	val = *reg_addr;
+	if (reg == AC97_GPIO_STATUS)
+		goto out;
+	wait_event_timeout(gsr_wq, gsr_bits & GSR_SDONE, 1);
+	if (!gsr_bits & GSR_SDONE) {
+		printk(KERN_ERR "%s: read error (ac97_reg=%d GSR=%#lx)\n",
+				__FUNCTION__, reg, gsr_bits);
+		val = -1;
+		goto out;
+	}
+
+	/* valid data now */
+	gsr_bits = 0;
+	val = *reg_addr;			
+	/* but we've just started another cycle... */
+	wait_event_timeout(gsr_wq, gsr_bits & GSR_SDONE, 1);
+
+out:	up(&car_mutex);
+	return val;
+}
+
+static void pxa2xx_ac97_write(ac97_t *ac97, unsigned short reg, unsigned short val)
+{
+	volatile u32 *reg_addr;
+
+	down(&car_mutex);
+
+	if (CAR & CAR_CAIP) {
+		printk(KERN_CRIT "%s: CAR_CAIP already set\n", __FUNCTION__);
+		goto out;
+	}
+
+	/* set up primary or secondary codec space */
+	reg_addr = (ac97->num & 1) ? &SAC_REG_BASE : &PAC_REG_BASE;
+	reg_addr += (reg >> 1);
+	gsr_bits = 0;
+	*reg_addr = val;
+	wait_event_timeout(gsr_wq, gsr_bits & GSR_CDONE, 1);
+	if (!gsr_bits & GSR_SDONE)
+		printk(KERN_ERR "%s: write error (ac97_reg=%d GSR=%#lx)\n",
+				__FUNCTION__, reg, gsr_bits);
+
+out:	up(&car_mutex);
+}
+
+static void pxa2xx_ac97_reset(ac97_t *ac97)
+{
+	/* First, try cold reset */
+	GCR &=  GCR_COLD_RST;  /* clear everything but nCRST */
+	GCR &= ~GCR_COLD_RST;  /* then assert nCRST */
+
+	gsr_bits = 0;
+#ifdef CONFIG_PXA27x
+	/* PXA27x Developers Manual section 13.5.2.2.1 */
+	pxa_set_cken(1 << 31, 1);
+	udelay(5);
+	pxa_set_cken(1 << 31, 0);
+	GCR = GCR_COLD_RST;
+	udelay(50);
+#else
+	GCR = GCR_COLD_RST;
+	GCR |= GCR_CDONE_IE|GCR_SDONE_IE;
+	wait_event_timeout(gsr_wq, gsr_bits & (GSR_PCR | GSR_SCR), 1);
+#endif
+
+	if (!((GSR | gsr_bits) & (GSR_PCR | GSR_SCR))) {
+		printk(KERN_INFO "%s: cold reset timeout (GSR=%#lx)\n",
+				 __FUNCTION__, gsr_bits);
+
+		/* let's try warm reset */
+		gsr_bits = 0;
+#ifdef CONFIG_PXA27x
+		/* warm reset broken on Bulverde,
+		   so manually keep AC97 reset high */
+		pxa_gpio_mode(113 | GPIO_OUT | GPIO_DFLT_HIGH); 
+		udelay(10);
+		GCR |= GCR_WARM_RST;
+		pxa_gpio_mode(113 | GPIO_ALT_FN_2_OUT);
+		udelay(50);
+#else
+		GCR |= GCR_WARM_RST|GCR_PRIRDY_IEN|GCR_SECRDY_IEN;;
+		wait_event_timeout(gsr_wq, gsr_bits & (GSR_PCR | GSR_SCR), 1);
+#endif			
+
+		if (!((GSR | gsr_bits) & (GSR_PCR | GSR_SCR)))
+			printk(KERN_INFO "%s: warm reset timeout (GSR=%#lx)\n",
+					 __FUNCTION__, gsr_bits);
+	}
+
+	GCR &= ~(GCR_PRIRDY_IEN|GCR_SECRDY_IEN);
+	GCR |= GCR_SDONE_IE|GCR_CDONE_IE;
+}
+
+static irqreturn_t pxa2xx_ac97_irq(int irq, void *dev_id, struct pt_regs *regs)
+{
+	long status;
+
+	status = GSR;
+	if (status) {
+		GSR = status;
+		gsr_bits |= status;
+		wake_up(&gsr_wq);
+
+#ifdef CONFIG_PXA27x
+		/* Although we don't use those we still need to clear them
+		   since they tend to spuriously trigger when MMC is used
+		   (hardware bug? go figure)... */
+		MISR = MISR_EOC;
+		PISR = PISR_EOC;
+		MCSR = MCSR_EOC;
+#endif
+
+		return IRQ_HANDLED;
+	}
+
+	return IRQ_NONE;
+}
+
+static ac97_bus_ops_t pxa2xx_ac97_ops = {
+	.read	= pxa2xx_ac97_read,
+	.write	= pxa2xx_ac97_write,
+	.reset	= pxa2xx_ac97_reset,
+};
+
+static pxa2xx_pcm_dma_params_t pxa2xx_ac97_pcm_out = {
+	.name			= "AC97 PCM out",
+	.dev_addr		= __PREG(PCDR),
+	.drcmr			= &DRCMRTXPCDR,
+	.dcmd			= DCMD_INCSRCADDR | DCMD_FLOWTRG |
+				  DCMD_BURST32 | DCMD_WIDTH4,
+};
+
+static pxa2xx_pcm_dma_params_t pxa2xx_ac97_pcm_in = {
+	.name			= "AC97 PCM in",
+	.dev_addr		= __PREG(PCDR),
+	.drcmr			= &DRCMRRXPCDR,
+	.dcmd			= DCMD_INCTRGADDR | DCMD_FLOWSRC |
+				  DCMD_BURST32 | DCMD_WIDTH4,
+};
+
+static snd_pcm_t *pxa2xx_ac97_pcm;
+static ac97_t *pxa2xx_ac97_ac97;
+
+static int pxa2xx_ac97_pcm_startup(snd_pcm_substream_t *substream)
+{
+	snd_pcm_runtime_t *runtime = substream->runtime;
+	pxa2xx_audio_ops_t *platform_ops;
+	int r;
+
+	runtime->hw.channels_min = 2;
+	runtime->hw.channels_max = 2;
+
+	r = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
+	    AC97_RATES_FRONT_DAC : AC97_RATES_ADC;
+	runtime->hw.rates = pxa2xx_ac97_ac97->rates[r];
+	snd_pcm_limit_hw_rates(runtime);
+
+       	platform_ops = substream->pcm->card->dev->platform_data;
+	if (platform_ops && platform_ops->startup)
+		return platform_ops->startup(substream, platform_ops->priv);
+	else
+		return 0;
+}
+
+static void pxa2xx_ac97_pcm_shutdown(snd_pcm_substream_t *substream)
+{
+	pxa2xx_audio_ops_t *platform_ops;
+
+       	platform_ops = substream->pcm->card->dev->platform_data;
+	if (platform_ops && platform_ops->shutdown)
+		platform_ops->shutdown(substream, platform_ops->priv);
+}
+
+static int pxa2xx_ac97_pcm_prepare(snd_pcm_substream_t *substream)
+{
+	snd_pcm_runtime_t *runtime = substream->runtime;
+	int reg = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
+		  AC97_PCM_FRONT_DAC_RATE : AC97_PCM_LR_ADC_RATE;
+	return snd_ac97_set_rate(pxa2xx_ac97_ac97, reg, runtime->rate);
+}
+
+static pxa2xx_pcm_client_t pxa2xx_ac97_pcm_client = {
+	.playback_params	= &pxa2xx_ac97_pcm_out,
+	.capture_params		= &pxa2xx_ac97_pcm_in,
+	.startup		= pxa2xx_ac97_pcm_startup,
+	.shutdown		= pxa2xx_ac97_pcm_shutdown,
+	.prepare		= pxa2xx_ac97_pcm_prepare,
+};
+
+#ifdef CONFIG_PM
+
+static int pxa2xx_ac97_do_suspend(snd_card_t *card, unsigned int state)
+{
+	if (card->power_state != SNDRV_CTL_POWER_D3cold) {
+		pxa2xx_audio_ops_t *platform_ops = card->dev->platform_data;
+		snd_pcm_suspend_all(pxa2xx_ac97_pcm);
+		snd_ac97_suspend(pxa2xx_ac97_ac97);
+		snd_power_change_state(card, SNDRV_CTL_POWER_D3cold);
+		if (platform_ops && platform_ops->suspend)
+			platform_ops->suspend(platform_ops->priv);
+		GCR |= GCR_ACLINK_OFF;
+		pxa_set_cken(CKEN2_AC97, 0);
+	}
+
+	return 0;
+}
+
+static int pxa2xx_ac97_do_resume(snd_card_t *card, unsigned int state)
+{
+	if (card->power_state != SNDRV_CTL_POWER_D0) {
+		pxa2xx_audio_ops_t *platform_ops = card->dev->platform_data;
+		pxa_set_cken(CKEN2_AC97, 1);
+		if (platform_ops && platform_ops->resume)
+			platform_ops->resume(platform_ops->priv);
+		snd_ac97_resume(pxa2xx_ac97_ac97);
+		snd_power_change_state(card, SNDRV_CTL_POWER_D0);
+	}
+
+	return 0;
+}
+
+static int pxa2xx_ac97_suspend(struct device *_dev, u32 state, u32 level)
+{
+	snd_card_t *card = dev_get_drvdata(_dev);
+	int ret = 0;
+
+	if (card && level == SUSPEND_DISABLE)
+		ret = pxa2xx_ac97_do_suspend(card, SNDRV_CTL_POWER_D3cold);
+
+	return ret;
+}
+
+static int pxa2xx_ac97_resume(struct device *_dev, u32 level)
+{
+	snd_card_t *card = dev_get_drvdata(_dev);
+	int ret = 0;
+
+	if (card && level == RESUME_ENABLE)
+		ret = pxa2xx_ac97_do_resume(card, SNDRV_CTL_POWER_D0);
+
+	return ret;
+}
+
+#else
+#define pxa2xx_ac97_suspend	NULL
+#define pxa2xx_ac97_resume	NULL
+#endif
+
+static int pxa2xx_ac97_probe(struct device *dev)
+{
+	snd_card_t *card;
+	ac97_bus_t *ac97_bus;
+	ac97_template_t ac97_template;
+	int ret;
+
+	ret = -ENOMEM;
+	card = snd_card_new(SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
+			    THIS_MODULE, 0);
+	if (!card)
+		goto err;
+
+	card->dev = dev;
+	strncpy(card->driver, dev->driver->name, sizeof(card->driver));
+
+	ret = pxa2xx_pcm_new(card, &pxa2xx_ac97_pcm_client, &pxa2xx_ac97_pcm);
+	if (ret)
+		goto err;
+
+	ret = request_irq(IRQ_AC97, pxa2xx_ac97_irq, 0, "AC97", NULL);
+	if (ret < 0)
+		goto err;
+
+	pxa_gpio_mode(GPIO31_SYNC_AC97_MD);
+	pxa_gpio_mode(GPIO30_SDATA_OUT_AC97_MD);
+	pxa_gpio_mode(GPIO28_BITCLK_AC97_MD);
+	pxa_gpio_mode(GPIO29_SDATA_IN_AC97_MD);
+#ifdef CONFIG_PXA27x
+	/* Use GPIO 113 as AC97 Reset on Bulverde */
+	pxa_gpio_mode(113 | GPIO_ALT_FN_2_OUT);
+#endif
+	pxa_set_cken(CKEN2_AC97, 1);
+
+	ret = snd_ac97_bus(card, 0, &pxa2xx_ac97_ops, NULL, &ac97_bus);
+	if (ret)
+		goto err;
+	memset(&ac97_template, 0, sizeof(ac97_template));
+	ret = snd_ac97_mixer(ac97_bus, &ac97_template, &pxa2xx_ac97_ac97);
+	if (ret)
+		goto err;
+
+	snprintf(card->shortname, sizeof(card->shortname),
+		 "%s", snd_ac97_get_short_name(pxa2xx_ac97_ac97));
+	snprintf(card->longname, sizeof(card->longname),
+		 "%s (%s)", dev->driver->name, card->mixername);
+
+	snd_card_set_pm_callback(card, pxa2xx_ac97_do_suspend,
+				 pxa2xx_ac97_do_resume, NULL);
+	ret = snd_card_register(card);
+	if (ret == 0) {
+		dev_set_drvdata(dev, card);
+		return 0;
+	}
+
+ err:
+	if (card)
+		snd_card_free(card);
+	if (CKEN & CKEN2_AC97) {
+		GCR |= GCR_ACLINK_OFF;
+		free_irq(IRQ_AC97, NULL);
+		pxa_set_cken(CKEN2_AC97, 0);
+	}
+	return ret;
+}
+
+static int pxa2xx_ac97_remove(struct device *dev)
+{
+	snd_card_t *card = dev_get_drvdata(dev);
+
+	if (card) {
+		snd_card_free(card);
+		dev_set_drvdata(dev, NULL);
+		GCR |= GCR_ACLINK_OFF;
+		free_irq(IRQ_AC97, NULL);
+		pxa_set_cken(CKEN2_AC97, 0);
+	}
+
+	return 0;
+}
+
+static struct device_driver pxa2xx_ac97_driver = {
+	.name		= "pxa2xx-ac97",
+	.bus		= &platform_bus_type,
+	.probe		= pxa2xx_ac97_probe,
+	.remove		= pxa2xx_ac97_remove,
+	.suspend	= pxa2xx_ac97_suspend,
+	.resume		= pxa2xx_ac97_resume,
+};
+
+static int __init pxa2xx_ac97_init(void)
+{
+	return driver_register(&pxa2xx_ac97_driver);
+}
+
+static void __exit pxa2xx_ac97_exit(void)
+{
+	driver_unregister(&pxa2xx_ac97_driver);
+}
+
+module_init(pxa2xx_ac97_init);
+module_exit(pxa2xx_ac97_exit);
+
+MODULE_AUTHOR("Nicolas Pitre");
+MODULE_DESCRIPTION("AC97 driver for the Intel PXA2xx chip");
+MODULE_LICENSE("GPL");

sound/arm/pxa2xx-pcm.c

+/*
+ * linux/sound/arm/pxa2xx-pcm.c -- ALSA PCM interface for the Intel PXA2xx chip
+ *
+ * Author:	Nicolas Pitre
+ * Created:	Nov 30, 2004
+ * Copyright:	(C) 2004 MontaVista Software, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/dma-mapping.h>
+
+#include <sound/driver.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+
+#include <asm/dma.h>
+#include <asm/hardware.h>
+#include <asm/arch/pxa-regs.h>
+
+#include "pxa2xx-pcm.h"
+
+
+static const snd_pcm_hardware_t pxa2xx_pcm_hardware = {
+	.info			= SNDRV_PCM_INFO_MMAP |
+				  SNDRV_PCM_INFO_MMAP_VALID |
+				  SNDRV_PCM_INFO_INTERLEAVED |
+				  SNDRV_PCM_INFO_PAUSE,
+	.formats		= SNDRV_PCM_FMTBIT_S16_LE,
+	.period_bytes_min	= 32,
+	.period_bytes_max	= 8192 - 32,
+	.periods_min		= 1,
+	.periods_max		= PAGE_SIZE/sizeof(pxa_dma_desc),
+	.buffer_bytes_max	= 128 * 1024,
+	.fifo_size		= 32,
+};
+
+struct pxa2xx_runtime_data {
+	int dma_ch;
+	pxa2xx_pcm_dma_params_t *params;
+	pxa_dma_desc *dma_desc_array;
+	dma_addr_t dma_desc_array_phys;
+};
+
+static int pxa2xx_pcm_hw_params(snd_pcm_substream_t *substream,
+				snd_pcm_hw_params_t *params)
+{
+	snd_pcm_runtime_t *runtime = substream->runtime;
+	struct pxa2xx_runtime_data *rtd = runtime->private_data;
+	size_t totsize = params_buffer_bytes(params);
+	size_t period = params_period_bytes(params);
+	pxa_dma_desc *dma_desc;
+	dma_addr_t dma_buff_phys, next_desc_phys;
+
+	snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
+	runtime->dma_bytes = totsize;
+
+	dma_desc = rtd->dma_desc_array;
+	next_desc_phys = rtd->dma_desc_array_phys;
+	dma_buff_phys = runtime->dma_addr;
+	do {
+		next_desc_phys += sizeof(pxa_dma_desc);
+		dma_desc->ddadr = next_desc_phys;
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+			dma_desc->dsadr = dma_buff_phys;
+			dma_desc->dtadr = rtd->params->dev_addr;
+		} else {
+			dma_desc->dsadr = rtd->params->dev_addr;
+			dma_desc->dtadr = dma_buff_phys;
+		}
+		if (period > totsize)
+			period = totsize;
+		dma_desc->dcmd = rtd->params->dcmd | period | DCMD_ENDIRQEN;
+		dma_desc++;
+		dma_buff_phys += period;
+	} while (totsize -= period);
+	dma_desc[-1].ddadr = rtd->dma_desc_array_phys;
+
+	return 0;
+}
+
+static int pxa2xx_pcm_hw_free(snd_pcm_substream_t *substream)
+{
+	struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
+
+	*rtd->params->drcmr = 0;
+	snd_pcm_set_runtime_buffer(substream, NULL);
+	return 0;
+}
+
+static int pxa2xx_pcm_prepare(snd_pcm_substream_t *substream)
+{
+	pxa2xx_pcm_client_t *client = substream->private_data;
+	snd_pcm_runtime_t *runtime = substream->runtime;
+	struct pxa2xx_runtime_data *rtd = runtime->private_data;
+
+	DCSR(rtd->dma_ch) &= ~DCSR_RUN;
+	DCSR(rtd->dma_ch) = 0;
+	DCMD(rtd->dma_ch) = 0;
+	*rtd->params->drcmr = rtd->dma_ch | DRCMR_MAPVLD;
+
+	return client->prepare(substream);
+}
+
+static int pxa2xx_pcm_trigger(snd_pcm_substream_t *substream, int cmd)
+{
+	struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
+	int ret = 0;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+		DDADR(rtd->dma_ch) = rtd->dma_desc_array_phys;
+		DCSR(rtd->dma_ch) = DCSR_RUN;
+		break;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		DCSR(rtd->dma_ch) &= ~DCSR_RUN;
+		break;
+
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		DCSR(rtd->dma_ch) |= DCSR_RUN;
+		break;
+
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static void pxa2xx_pcm_dma_irq(int dma_ch, void *dev_id, struct pt_regs *regs)
+{
+	snd_pcm_substream_t *substream = dev_id;
+	struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
+	int dcsr;
+
+	dcsr = DCSR(dma_ch);
+	DCSR(dma_ch) = dcsr & ~DCSR_STOPIRQEN;
+
+	if (dcsr & DCSR_ENDINTR) {
+		snd_pcm_period_elapsed(substream);
+	} else {
+		printk( KERN_ERR "%s: DMA error on channel %d (DCSR=%#x)\n",
+			rtd->params->name, dma_ch, dcsr );
+		snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
+	}
+}
+
+static snd_pcm_uframes_t pxa2xx_pcm_pointer(snd_pcm_substream_t *substream)
+{
+	snd_pcm_runtime_t *runtime = substream->runtime;
+	struct pxa2xx_runtime_data *rtd = runtime->private_data;
+	dma_addr_t ptr = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
+			 DSADR(rtd->dma_ch) : DTADR(rtd->dma_ch);
+	snd_pcm_uframes_t x = bytes_to_frames(runtime, ptr - runtime->dma_addr);
+	if (x == runtime->buffer_size)
+		x = 0;
+	return x;
+}
+
+static int
+pxa2xx_pcm_hw_rule_mult32(snd_pcm_hw_params_t *params, snd_pcm_hw_rule_t *rule)
+{
+	snd_interval_t *i = hw_param_interval(params, rule->var);
+	int changed = 0;
+
+	if (i->min & 31) {
+		i->min = (i->min & ~31) + 32;
+		i->openmin = 0;
+		changed = 1;
+	}
+
+	if (i->max & 31) {
+		i->max &= ~31;
+		i->openmax = 0;
+		changed = 1;
+	}
+
+	return changed;
+}
+
+static int pxa2xx_pcm_open(snd_pcm_substream_t *substream)
+{
+	pxa2xx_pcm_client_t *client = substream->private_data;
+	snd_pcm_runtime_t *runtime = substream->runtime;
+	struct pxa2xx_runtime_data *rtd;
+	int ret;
+
+	runtime->hw = pxa2xx_pcm_hardware;
+
+	/*
+	 * For mysterious reasons (and despite what the manual says)
+	 * playback samples are lost if the DMA count is not a multiple
+	 * of the DMA burst size.  Let's add a rule to enforce that.
+	 */
+	ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
+				  pxa2xx_pcm_hw_rule_mult32, NULL,
+				  SNDRV_PCM_HW_PARAM_PERIOD_BYTES, -1);
+	if (ret)
+		goto out;
+	ret = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
+				  pxa2xx_pcm_hw_rule_mult32, NULL,
+				  SNDRV_PCM_HW_PARAM_BUFFER_BYTES, -1);
+	if (ret)
+		goto out;
+
+	ret = -ENOMEM;
+	rtd = kmalloc(sizeof(*rtd), GFP_KERNEL);
+	if (!rtd)
+		goto out;
+	rtd->dma_desc_array =
+		dma_alloc_writecombine(substream->pcm->card->dev, PAGE_SIZE,
+				       &rtd->dma_desc_array_phys, GFP_KERNEL);
+	if (!rtd->dma_desc_array)
+		goto err1;
+
+	rtd->params = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
+		      client->playback_params : client->capture_params;
+	ret = pxa_request_dma(rtd->params->name, DMA_PRIO_LOW,
+			      pxa2xx_pcm_dma_irq, substream);
+	if (ret < 0)
+		goto err2;
+	rtd->dma_ch = ret;
+
+	runtime->private_data = rtd;
+	ret = client->startup(substream);
+	if (!ret)
+		goto out;
+
+	pxa_free_dma(rtd->dma_ch);
+ err2:
+	dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
+			      rtd->dma_desc_array, rtd->dma_desc_array_phys);
+ err1:
+	kfree(rtd);
+ out:
+	return ret;
+}
+
+static int pxa2xx_pcm_close(snd_pcm_substream_t *substream)
+{
+	pxa2xx_pcm_client_t *client = substream->private_data;
+	struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
+
+	pxa_free_dma(rtd->dma_ch);
+	client->shutdown(substream);
+	dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
+			      rtd->dma_desc_array, rtd->dma_desc_array_phys);
+	kfree(rtd);
+	return 0;
+}
+
+static int
+pxa2xx_pcm_mmap(snd_pcm_substream_t *substream, struct vm_area_struct *vma)
+{
+	snd_pcm_runtime_t *runtime = substream->runtime;
+	return dma_mmap_writecombine(substream->pcm->card->dev, vma,
+				     runtime->dma_area,
+				     runtime->dma_addr,
+				     runtime->dma_bytes);
+}
+
+static snd_pcm_ops_t pxa2xx_pcm_ops = {
+	.open		= pxa2xx_pcm_open,
+	.close		= pxa2xx_pcm_close,
+	.ioctl		= snd_pcm_lib_ioctl,
+	.hw_params	= pxa2xx_pcm_hw_params,
+	.hw_free	= pxa2xx_pcm_hw_free,
+	.prepare	= pxa2xx_pcm_prepare,
+	.trigger	= pxa2xx_pcm_trigger,
+	.pointer	= pxa2xx_pcm_pointer,
+	.mmap		= pxa2xx_pcm_mmap,
+};
+
+static int pxa2xx_pcm_preallocate_dma_buffer(snd_pcm_t *pcm, int stream)
+{
+	snd_pcm_substream_t *substream = pcm->streams[stream].substream;
+	struct snd_dma_buffer *buf = &substream->dma_buffer;
+	size_t size = pxa2xx_pcm_hardware.buffer_bytes_max;
+	buf->dev.type = SNDRV_DMA_TYPE_DEV;
+	buf->dev.dev = pcm->card->dev;
+	buf->private_data = NULL;
+	buf->area = dma_alloc_writecombine(pcm->card->dev, size,
+					   &buf->addr, GFP_KERNEL);
+	if (!buf->area)
+		return -ENOMEM;
+	buf->bytes = size;
+	return 0;
+}
+
+static void pxa2xx_pcm_free_dma_buffers(snd_pcm_t *pcm)
+{
+	snd_pcm_substream_t *substream;
+	struct snd_dma_buffer *buf;
+	int stream;
+
+	for (stream = 0; stream < 2; stream++) {
+		substream = pcm->streams[stream].substream;
+		if (!substream)
+			continue;
+		buf = &substream->dma_buffer;
+		if (!buf->area)
+			continue;
+		dma_free_writecombine(pcm->card->dev, buf->bytes,
+				      buf->area, buf->addr);
+		buf->area = NULL;
+	}
+}
+
+static u64 pxa2xx_pcm_dmamask = 0xffffffff;
+
+int pxa2xx_pcm_new(snd_card_t *card, pxa2xx_pcm_client_t *client, snd_pcm_t **rpcm)
+{
+	snd_pcm_t *pcm;
+	int play = client->playback_params ? 1 : 0;
+	int capt = client->capture_params ? 1 : 0;
+	int ret;
+
+	ret = snd_pcm_new(card, "PXA2xx-PCM", 0, play, capt, &pcm);
+	if (ret)
+		goto out;
+
+	pcm->private_data = client;
+	pcm->private_free = pxa2xx_pcm_free_dma_buffers;
+
+	if (!card->dev->dma_mask)
+		card->dev->dma_mask = &pxa2xx_pcm_dmamask;
+	if (!card->dev->coherent_dma_mask)
+		card->dev->coherent_dma_mask = 0xffffffff;
+
+	if (play) {
+		int stream = SNDRV_PCM_STREAM_PLAYBACK;
+		snd_pcm_set_ops(pcm, stream, &pxa2xx_pcm_ops);
+		ret = pxa2xx_pcm_preallocate_dma_buffer(pcm, stream);
+		if (ret)
+			goto out;
+	}
+	if (capt) {
+		int stream = SNDRV_PCM_STREAM_CAPTURE;
+		snd_pcm_set_ops(pcm, stream, &pxa2xx_pcm_ops);
+		ret = pxa2xx_pcm_preallocate_dma_buffer(pcm, stream);
+		if (ret)
+			goto out;
+	}
+
+	if (rpcm)
+		*rpcm = pcm;
+	ret = 0;
+
+ out:
+	return ret;
+}
+
+EXPORT_SYMBOL(pxa2xx_pcm_new);
+
+MODULE_AUTHOR("Nicolas Pitre");
+MODULE_DESCRIPTION("Intel PXA2xx PCM DMA module");
+MODULE_LICENSE("GPL");

sound/arm/pxa2xx-pcm.h

+/*
+ * linux/sound/arm/pxa2xx-pcm.h -- ALSA PCM interface for the Intel PXA2xx chip
+ *
+ * Author:	Nicolas Pitre
+ * Created:	Nov 30, 2004
+ * Copyright:	MontaVista Software, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+typedef struct {
+	char *name;			/* stream identifier */
+	u32 dcmd;			/* DMA descriptor dcmd field */
+	volatile u32 *drcmr;		/* the DMA request channel to use */
+	u32 dev_addr;			/* device physical address for DMA */
+} pxa2xx_pcm_dma_params_t;
+	
+typedef struct {
+	pxa2xx_pcm_dma_params_t *playback_params;
+	pxa2xx_pcm_dma_params_t *capture_params;
+	int (*startup)(snd_pcm_substream_t *);
+	void (*shutdown)(snd_pcm_substream_t *);
+	int (*prepare)(snd_pcm_substream_t *);
+} pxa2xx_pcm_client_t;
+
+extern int pxa2xx_pcm_new(snd_card_t *, pxa2xx_pcm_client_t *, snd_pcm_t **);
+