[ALSA] Add ARM PXA2xx AC97 driver (2c484df0) · Commits · e / devices / android_kernel_xiaomi_markw

Documentation/sound/alsa/ALSA-Configuration.txt

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		@@ -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

+13 −1

Original line number	Diff line number	Diff line
		@@ -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

+5 −3

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		@@ -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

0 → 100644

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		/*
		* 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

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		/*
		* 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");