sound/soc/au1x/psc-ac97.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Au12x0/Au1550 PSC ALSA ASoC audio support.
  *
  * (c) 2007-2009 MSC Vertriebsges.m.b.H.,
  *	Manuel Lauss <manuel.lauss@gmail.com>
  *
  * Au1xxx-PSC AC97 glue.
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/device.h>
 #include <linux/delay.h>
 #include <linux/mutex.h>
 #include <linux/suspend.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/initval.h>
 #include <sound/soc.h>
 #include <asm/mach-au1x00/au1000.h>
 #include <asm/mach-au1x00/au1xxx_psc.h>

 #include "psc.h"

 /* how often to retry failed codec register reads/writes */
 #define AC97_RW_RETRIES	5

 #define AC97_DIR	\
 	(SND_SOC_DAIDIR_PLAYBACK | SND_SOC_DAIDIR_CAPTURE)

 #define AC97_RATES	\
 	SNDRV_PCM_RATE_8000_48000

 #define AC97_FMTS	\
 	(SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3BE)

 #define AC97PCR_START(stype)	\
 	((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TS : PSC_AC97PCR_RS)
 #define AC97PCR_STOP(stype)	\
 	((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TP : PSC_AC97PCR_RP)
 #define AC97PCR_CLRFIFO(stype)	\
 	((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TC : PSC_AC97PCR_RC)

 #define AC97STAT_BUSY(stype)	\
 	((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97STAT_TB : PSC_AC97STAT_RB)

 /* instance data. There can be only one, MacLeod!!!! */
 static struct au1xpsc_audio_data *au1xpsc_ac97_workdata;

 #if 0

 /* this could theoretically work, but ac97->bus->card->private_data can be NULL
  * when snd_ac97_mixer() is called; I don't know if the rest further down the
  * chain are always valid either.
  */
 static inline struct au1xpsc_audio_data *ac97_to_pscdata(struct snd_ac97 *x)
 {
 	struct snd_soc_card *c = x->bus->card->private_data;
 	return snd_soc_dai_get_drvdata(c->rtd->cpu_dai);
 }

 #else

 #define ac97_to_pscdata(x)	au1xpsc_ac97_workdata

 #endif

 /* AC97 controller reads codec register */
 static unsigned short au1xpsc_ac97_read(struct snd_ac97 *ac97,
 					unsigned short reg)
 {
 	struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
 	unsigned short retry, tmo;
 	unsigned long data;

 	__raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
 	wmb(); /* drain writebuffer */

 	retry = AC97_RW_RETRIES;
 	do {
 		mutex_lock(&pscdata->lock);

 		__raw_writel(PSC_AC97CDC_RD | PSC_AC97CDC_INDX(reg),
 			  AC97_CDC(pscdata));
 		wmb(); /* drain writebuffer */

 		tmo = 20;
 		do {
 			udelay(21);
 			if (__raw_readl(AC97_EVNT(pscdata)) & PSC_AC97EVNT_CD)
 				break;
 		} while (--tmo);

 		data = __raw_readl(AC97_CDC(pscdata));

 		__raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
 		wmb(); /* drain writebuffer */

 		mutex_unlock(&pscdata->lock);

 		if (reg != ((data >> 16) & 0x7f))
 			tmo = 1;	/* wrong register, try again */

 	} while (--retry && !tmo);

 	return retry ? data & 0xffff : 0xffff;
 }

 /* AC97 controller writes to codec register */
 static void au1xpsc_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
 				unsigned short val)
 {
 	struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
 	unsigned int tmo, retry;

 	__raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
 	wmb(); /* drain writebuffer */

 	retry = AC97_RW_RETRIES;
 	do {
 		mutex_lock(&pscdata->lock);

 		__raw_writel(PSC_AC97CDC_INDX(reg) | (val & 0xffff),
 			  AC97_CDC(pscdata));
 		wmb(); /* drain writebuffer */

 		tmo = 20;
 		do {
 			udelay(21);
 			if (__raw_readl(AC97_EVNT(pscdata)) & PSC_AC97EVNT_CD)
 				break;
 		} while (--tmo);

 		__raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
 		wmb(); /* drain writebuffer */

 		mutex_unlock(&pscdata->lock);
 	} while (--retry && !tmo);
 }

 /* AC97 controller asserts a warm reset */
 static void au1xpsc_ac97_warm_reset(struct snd_ac97 *ac97)
 {
 	struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);

 	__raw_writel(PSC_AC97RST_SNC, AC97_RST(pscdata));
 	wmb(); /* drain writebuffer */
 	msleep(10);
 	__raw_writel(0, AC97_RST(pscdata));
 	wmb(); /* drain writebuffer */
 }

 static void au1xpsc_ac97_cold_reset(struct snd_ac97 *ac97)
 {
 	struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
 	int i;

 	/* disable PSC during cold reset */
 	__raw_writel(0, AC97_CFG(au1xpsc_ac97_workdata));
 	wmb(); /* drain writebuffer */
 	__raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(pscdata));
 	wmb(); /* drain writebuffer */

 	/* issue cold reset */
 	__raw_writel(PSC_AC97RST_RST, AC97_RST(pscdata));
 	wmb(); /* drain writebuffer */
 	msleep(500);
 	__raw_writel(0, AC97_RST(pscdata));
 	wmb(); /* drain writebuffer */

 	/* enable PSC */
 	__raw_writel(PSC_CTRL_ENABLE, PSC_CTRL(pscdata));
 	wmb(); /* drain writebuffer */

 	/* wait for PSC to indicate it's ready */
 	i = 1000;
 	while (!((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_SR)) && (--i))
 		msleep(1);

 	if (i == 0) {
 		printk(KERN_ERR "au1xpsc-ac97: PSC not ready!\n");
 		return;
 	}

 	/* enable the ac97 function */
 	__raw_writel(pscdata->cfg | PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
 	wmb(); /* drain writebuffer */

 	/* wait for AC97 core to become ready */
 	i = 1000;
 	while (!((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR)) && (--i))
 		msleep(1);
 	if (i == 0)
 		printk(KERN_ERR "au1xpsc-ac97: AC97 ctrl not ready\n");
 }

 /* AC97 controller operations */
 static struct snd_ac97_bus_ops psc_ac97_ops = {
 	.read		= au1xpsc_ac97_read,
 	.write		= au1xpsc_ac97_write,
 	.reset		= au1xpsc_ac97_cold_reset,
 	.warm_reset	= au1xpsc_ac97_warm_reset,
 };

 static int au1xpsc_ac97_hw_params(struct snd_pcm_substream *substream,
 				  struct snd_pcm_hw_params *params,
 				  struct snd_soc_dai *dai)
 {
 	struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
 	unsigned long r, ro, stat;
 	int chans, t, stype = substream->stream;

 	chans = params_channels(params);

 	r = ro = __raw_readl(AC97_CFG(pscdata));
 	stat = __raw_readl(AC97_STAT(pscdata));

 	/* already active? */
 	if (stat & (PSC_AC97STAT_TB | PSC_AC97STAT_RB)) {
 		/* reject parameters not currently set up */
 		if ((PSC_AC97CFG_GET_LEN(r) != params->msbits) ||
 		    (pscdata->rate != params_rate(params)))
 			return -EINVAL;
 	} else {

 		/* set sample bitdepth: REG[24:21]=(BITS-2)/2 */
 		r &= ~PSC_AC97CFG_LEN_MASK;
 		r |= PSC_AC97CFG_SET_LEN(params->msbits);

 		/* channels: enable slots for front L/R channel */
 		if (stype == SNDRV_PCM_STREAM_PLAYBACK) {
 			r &= ~PSC_AC97CFG_TXSLOT_MASK;
 			r |= PSC_AC97CFG_TXSLOT_ENA(3);
 			r |= PSC_AC97CFG_TXSLOT_ENA(4);
 		} else {
 			r &= ~PSC_AC97CFG_RXSLOT_MASK;
 			r |= PSC_AC97CFG_RXSLOT_ENA(3);
 			r |= PSC_AC97CFG_RXSLOT_ENA(4);
 		}

 		/* do we need to poke the hardware? */
 		if (!(r ^ ro))
 			goto out;

 		/* ac97 engine is about to be disabled */
 		mutex_lock(&pscdata->lock);

 		/* disable AC97 device controller first... */
 		__raw_writel(r & ~PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
 		wmb(); /* drain writebuffer */

 		/* ...wait for it... */
 		t = 100;
 		while ((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR) && --t)
 			msleep(1);

 		if (!t)
 			printk(KERN_ERR "PSC-AC97: can't disable!\n");

 		/* ...write config... */
 		__raw_writel(r, AC97_CFG(pscdata));
 		wmb(); /* drain writebuffer */

 		/* ...enable the AC97 controller again... */
 		__raw_writel(r | PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
 		wmb(); /* drain writebuffer */

 		/* ...and wait for ready bit */
 		t = 100;
 		while ((!(__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR)) && --t)
 			msleep(1);

 		if (!t)
 			printk(KERN_ERR "PSC-AC97: can't enable!\n");

 		mutex_unlock(&pscdata->lock);

 		pscdata->cfg = r;
 		pscdata->rate = params_rate(params);
 	}

 out:
 	return 0;
 }

 static int au1xpsc_ac97_trigger(struct snd_pcm_substream *substream,
 				int cmd, struct snd_soc_dai *dai)
 {
 	struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
 	int ret, stype = substream->stream;

 	ret = 0;

 	switch (cmd) {
 	case SNDRV_PCM_TRIGGER_START:
 	case SNDRV_PCM_TRIGGER_RESUME:
 		__raw_writel(AC97PCR_CLRFIFO(stype), AC97_PCR(pscdata));
 		wmb(); /* drain writebuffer */
 		__raw_writel(AC97PCR_START(stype), AC97_PCR(pscdata));
 		wmb(); /* drain writebuffer */
 		break;
 	case SNDRV_PCM_TRIGGER_STOP:
 	case SNDRV_PCM_TRIGGER_SUSPEND:
 		__raw_writel(AC97PCR_STOP(stype), AC97_PCR(pscdata));
 		wmb(); /* drain writebuffer */

 		while (__raw_readl(AC97_STAT(pscdata)) & AC97STAT_BUSY(stype))
 			asm volatile ("nop");

 		__raw_writel(AC97PCR_CLRFIFO(stype), AC97_PCR(pscdata));
 		wmb(); /* drain writebuffer */

 		break;
 	default:
 		ret = -EINVAL;
 	}
 	return ret;
 }

 static int au1xpsc_ac97_startup(struct snd_pcm_substream *substream,
 				struct snd_soc_dai *dai)
 {
 	struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
 	snd_soc_dai_set_dma_data(dai, substream, &pscdata->dmaids[0]);
 	return 0;
 }

 static int au1xpsc_ac97_probe(struct snd_soc_dai *dai)
 {
 	return au1xpsc_ac97_workdata ? 0 : -ENODEV;
 }

 static const struct snd_soc_dai_ops au1xpsc_ac97_dai_ops = {
 	.startup	= au1xpsc_ac97_startup,
 	.trigger	= au1xpsc_ac97_trigger,
 	.hw_params	= au1xpsc_ac97_hw_params,
 };

 static const struct snd_soc_dai_driver au1xpsc_ac97_dai_template = {
 	.bus_control		= true,
 	.probe			= au1xpsc_ac97_probe,
 	.playback = {
 		.rates		= AC97_RATES,
 		.formats	= AC97_FMTS,
 		.channels_min	= 2,
 		.channels_max	= 2,
 	},
 	.capture = {
 		.rates		= AC97_RATES,
 		.formats	= AC97_FMTS,
 		.channels_min	= 2,
 		.channels_max	= 2,
 	},
 	.ops = &au1xpsc_ac97_dai_ops,
 };

 static const struct snd_soc_component_driver au1xpsc_ac97_component = {
 	.name		= "au1xpsc-ac97",
 };

 static int au1xpsc_ac97_drvprobe(struct platform_device *pdev)
 {
 	int ret;
 	struct resource *iores, *dmares;
 	unsigned long sel;
 	struct au1xpsc_audio_data *wd;

 	wd = devm_kzalloc(&pdev->dev, sizeof(struct au1xpsc_audio_data),
 			  GFP_KERNEL);
 	if (!wd)
 		return -ENOMEM;

 	mutex_init(&wd->lock);

 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	wd->mmio = devm_ioremap_resource(&pdev->dev, iores);
 	if (IS_ERR(wd->mmio))
 		return PTR_ERR(wd->mmio);

 	dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 	if (!dmares)
 		return -EBUSY;
 	wd->dmaids[SNDRV_PCM_STREAM_PLAYBACK] = dmares->start;

 	dmares = platform_get_resource(pdev, IORESOURCE_DMA, 1);
 	if (!dmares)
 		return -EBUSY;
 	wd->dmaids[SNDRV_PCM_STREAM_CAPTURE] = dmares->start;

 	/* configuration: max dma trigger threshold, enable ac97 */
 	wd->cfg = PSC_AC97CFG_RT_FIFO8 | PSC_AC97CFG_TT_FIFO8 |
 		  PSC_AC97CFG_DE_ENABLE;

 	/* preserve PSC clock source set up by platform	 */
 	sel = __raw_readl(PSC_SEL(wd)) & PSC_SEL_CLK_MASK;
 	__raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
 	wmb(); /* drain writebuffer */
 	__raw_writel(0, PSC_SEL(wd));
 	wmb(); /* drain writebuffer */
 	__raw_writel(PSC_SEL_PS_AC97MODE | sel, PSC_SEL(wd));
 	wmb(); /* drain writebuffer */

 	/* name the DAI like this device instance ("au1xpsc-ac97.PSCINDEX") */
 	memcpy(&wd->dai_drv, &au1xpsc_ac97_dai_template,
 	       sizeof(struct snd_soc_dai_driver));
 	wd->dai_drv.name = dev_name(&pdev->dev);

 	platform_set_drvdata(pdev, wd);

 	ret = snd_soc_set_ac97_ops(&psc_ac97_ops);
 	if (ret)
 		return ret;

 	ret = snd_soc_register_component(&pdev->dev, &au1xpsc_ac97_component,
 					 &wd->dai_drv, 1);
 	if (ret)
 		return ret;

 	au1xpsc_ac97_workdata = wd;
 	return 0;
 }

 static int au1xpsc_ac97_drvremove(struct platform_device *pdev)
 {
 	struct au1xpsc_audio_data *wd = platform_get_drvdata(pdev);

 	snd_soc_unregister_component(&pdev->dev);

 	/* disable PSC completely */
 	__raw_writel(0, AC97_CFG(wd));
 	wmb(); /* drain writebuffer */
 	__raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
 	wmb(); /* drain writebuffer */

 	au1xpsc_ac97_workdata = NULL;	/* MDEV */

 	return 0;
 }

 #ifdef CONFIG_PM
 static int au1xpsc_ac97_drvsuspend(struct device *dev)
 {
 	struct au1xpsc_audio_data *wd = dev_get_drvdata(dev);

 	/* save interesting registers and disable PSC */
 	wd->pm[0] = __raw_readl(PSC_SEL(wd));

 	__raw_writel(0, AC97_CFG(wd));
 	wmb(); /* drain writebuffer */
 	__raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
 	wmb(); /* drain writebuffer */

 	return 0;
 }

 static int au1xpsc_ac97_drvresume(struct device *dev)
 {
 	struct au1xpsc_audio_data *wd = dev_get_drvdata(dev);

 	/* restore PSC clock config */
 	__raw_writel(wd->pm[0] | PSC_SEL_PS_AC97MODE, PSC_SEL(wd));
 	wmb(); /* drain writebuffer */

 	/* after this point the ac97 core will cold-reset the codec.
 	 * During cold-reset the PSC is reinitialized and the last
 	 * configuration set up in hw_params() is restored.
 	 */
 	return 0;
 }

 static const struct dev_pm_ops au1xpscac97_pmops = {
 	.suspend	= au1xpsc_ac97_drvsuspend,
 	.resume		= au1xpsc_ac97_drvresume,
 };

 #define AU1XPSCAC97_PMOPS &au1xpscac97_pmops

 #else

 #define AU1XPSCAC97_PMOPS NULL

 #endif

 static struct platform_driver au1xpsc_ac97_driver = {
 	.driver	= {
 		.name	= "au1xpsc_ac97",
 		.pm	= AU1XPSCAC97_PMOPS,
 	},
 	.probe		= au1xpsc_ac97_drvprobe,
 	.remove		= au1xpsc_ac97_drvremove,
 };

 module_platform_driver(au1xpsc_ac97_driver);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Au12x0/Au1550 PSC AC97 ALSA ASoC audio driver");
 MODULE_AUTHOR("Manuel Lauss");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Au12x0/Au1550 PSC ALSA ASoC audio support.
	*
	* (c) 2007-2009 MSC Vertriebsges.m.b.H.,
	* Manuel Lauss <manuel.lauss@gmail.com>
	*
	* Au1xxx-PSC AC97 glue.
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/device.h>
	#include <linux/delay.h>
	#include <linux/mutex.h>
	#include <linux/suspend.h>
	#include <sound/core.h>
	#include <sound/pcm.h>
	#include <sound/initval.h>
	#include <sound/soc.h>
	#include <asm/mach-au1x00/au1000.h>
	#include <asm/mach-au1x00/au1xxx_psc.h>

	#include "psc.h"

	/* how often to retry failed codec register reads/writes */
	#define AC97_RW_RETRIES 5

	#define AC97_DIR \
	(SND_SOC_DAIDIR_PLAYBACK \| SND_SOC_DAIDIR_CAPTURE)

	#define AC97_RATES \
	SNDRV_PCM_RATE_8000_48000

	#define AC97_FMTS \
	(SNDRV_PCM_FMTBIT_S16_LE \| SNDRV_PCM_FMTBIT_S20_3BE)

	#define AC97PCR_START(stype) \
	((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TS : PSC_AC97PCR_RS)
	#define AC97PCR_STOP(stype) \
	((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TP : PSC_AC97PCR_RP)
	#define AC97PCR_CLRFIFO(stype) \
	((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97PCR_TC : PSC_AC97PCR_RC)

	#define AC97STAT_BUSY(stype) \
	((stype) == SNDRV_PCM_STREAM_PLAYBACK ? PSC_AC97STAT_TB : PSC_AC97STAT_RB)

	/* instance data. There can be only one, MacLeod!!!! */
	static struct au1xpsc_audio_data *au1xpsc_ac97_workdata;

	#if 0

	/* this could theoretically work, but ac97->bus->card->private_data can be NULL
	* when snd_ac97_mixer() is called; I don't know if the rest further down the
	* chain are always valid either.
	*/
	static inline struct au1xpsc_audio_data ac97_to_pscdata(struct snd_ac97 x)
	{
	struct snd_soc_card *c = x->bus->card->private_data;
	return snd_soc_dai_get_drvdata(c->rtd->cpu_dai);
	}

	#else

	#define ac97_to_pscdata(x) au1xpsc_ac97_workdata

	#endif

	/* AC97 controller reads codec register */
	static unsigned short au1xpsc_ac97_read(struct snd_ac97 *ac97,
	unsigned short reg)
	{
	struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
	unsigned short retry, tmo;
	unsigned long data;

	__raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
	wmb(); /* drain writebuffer */

	retry = AC97_RW_RETRIES;
	do {
	mutex_lock(&pscdata->lock);

	__raw_writel(PSC_AC97CDC_RD \| PSC_AC97CDC_INDX(reg),
	AC97_CDC(pscdata));
	wmb(); /* drain writebuffer */

	tmo = 20;
	do {
	udelay(21);
	if (__raw_readl(AC97_EVNT(pscdata)) & PSC_AC97EVNT_CD)
	break;
	} while (--tmo);

	data = __raw_readl(AC97_CDC(pscdata));

	__raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
	wmb(); /* drain writebuffer */

	mutex_unlock(&pscdata->lock);

	if (reg != ((data >> 16) & 0x7f))
	tmo = 1; /* wrong register, try again */

	} while (--retry && !tmo);

	return retry ? data & 0xffff : 0xffff;
	}

	/* AC97 controller writes to codec register */
	static void au1xpsc_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
	unsigned short val)
	{
	struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
	unsigned int tmo, retry;

	__raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
	wmb(); /* drain writebuffer */

	retry = AC97_RW_RETRIES;
	do {
	mutex_lock(&pscdata->lock);

	__raw_writel(PSC_AC97CDC_INDX(reg) \| (val & 0xffff),
	AC97_CDC(pscdata));
	wmb(); /* drain writebuffer */

	tmo = 20;
	do {
	udelay(21);
	if (__raw_readl(AC97_EVNT(pscdata)) & PSC_AC97EVNT_CD)
	break;
	} while (--tmo);

	__raw_writel(PSC_AC97EVNT_CD, AC97_EVNT(pscdata));
	wmb(); /* drain writebuffer */

	mutex_unlock(&pscdata->lock);
	} while (--retry && !tmo);
	}

	/* AC97 controller asserts a warm reset */
	static void au1xpsc_ac97_warm_reset(struct snd_ac97 *ac97)
	{
	struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);

	__raw_writel(PSC_AC97RST_SNC, AC97_RST(pscdata));
	wmb(); /* drain writebuffer */
	msleep(10);
	__raw_writel(0, AC97_RST(pscdata));
	wmb(); /* drain writebuffer */
	}

	static void au1xpsc_ac97_cold_reset(struct snd_ac97 *ac97)
	{
	struct au1xpsc_audio_data *pscdata = ac97_to_pscdata(ac97);
	int i;

	/* disable PSC during cold reset */
	__raw_writel(0, AC97_CFG(au1xpsc_ac97_workdata));
	wmb(); /* drain writebuffer */
	__raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(pscdata));
	wmb(); /* drain writebuffer */

	/* issue cold reset */
	__raw_writel(PSC_AC97RST_RST, AC97_RST(pscdata));
	wmb(); /* drain writebuffer */
	msleep(500);
	__raw_writel(0, AC97_RST(pscdata));
	wmb(); /* drain writebuffer */

	/* enable PSC */
	__raw_writel(PSC_CTRL_ENABLE, PSC_CTRL(pscdata));
	wmb(); /* drain writebuffer */

	/* wait for PSC to indicate it's ready */
	i = 1000;
	while (!((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_SR)) && (--i))
	msleep(1);

	if (i == 0) {
	printk(KERN_ERR "au1xpsc-ac97: PSC not ready!\n");
	return;
	}

	/* enable the ac97 function */
	__raw_writel(pscdata->cfg \| PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
	wmb(); /* drain writebuffer */

	/* wait for AC97 core to become ready */
	i = 1000;
	while (!((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR)) && (--i))
	msleep(1);
	if (i == 0)
	printk(KERN_ERR "au1xpsc-ac97: AC97 ctrl not ready\n");
	}

	/* AC97 controller operations */
	static struct snd_ac97_bus_ops psc_ac97_ops = {
	.read = au1xpsc_ac97_read,
	.write = au1xpsc_ac97_write,
	.reset = au1xpsc_ac97_cold_reset,
	.warm_reset = au1xpsc_ac97_warm_reset,
	};

	static int au1xpsc_ac97_hw_params(struct snd_pcm_substream *substream,
	struct snd_pcm_hw_params *params,
	struct snd_soc_dai *dai)
	{
	struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
	unsigned long r, ro, stat;
	int chans, t, stype = substream->stream;

	chans = params_channels(params);

	r = ro = __raw_readl(AC97_CFG(pscdata));
	stat = __raw_readl(AC97_STAT(pscdata));

	/* already active? */
	if (stat & (PSC_AC97STAT_TB \| PSC_AC97STAT_RB)) {
	/* reject parameters not currently set up */
	if ((PSC_AC97CFG_GET_LEN(r) != params->msbits) \|\|
	(pscdata->rate != params_rate(params)))
	return -EINVAL;
	} else {

	/* set sample bitdepth: REG[24:21]=(BITS-2)/2 */
	r &= ~PSC_AC97CFG_LEN_MASK;
	r \|= PSC_AC97CFG_SET_LEN(params->msbits);

	/* channels: enable slots for front L/R channel */
	if (stype == SNDRV_PCM_STREAM_PLAYBACK) {
	r &= ~PSC_AC97CFG_TXSLOT_MASK;
	r \|= PSC_AC97CFG_TXSLOT_ENA(3);
	r \|= PSC_AC97CFG_TXSLOT_ENA(4);
	} else {
	r &= ~PSC_AC97CFG_RXSLOT_MASK;
	r \|= PSC_AC97CFG_RXSLOT_ENA(3);
	r \|= PSC_AC97CFG_RXSLOT_ENA(4);
	}

	/* do we need to poke the hardware? */
	if (!(r ^ ro))
	goto out;

	/* ac97 engine is about to be disabled */
	mutex_lock(&pscdata->lock);

	/* disable AC97 device controller first... */
	__raw_writel(r & ~PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
	wmb(); /* drain writebuffer */

	/* ...wait for it... */
	t = 100;
	while ((__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR) && --t)
	msleep(1);

	if (!t)
	printk(KERN_ERR "PSC-AC97: can't disable!\n");

	/* ...write config... */
	__raw_writel(r, AC97_CFG(pscdata));
	wmb(); /* drain writebuffer */

	/* ...enable the AC97 controller again... */
	__raw_writel(r \| PSC_AC97CFG_DE_ENABLE, AC97_CFG(pscdata));
	wmb(); /* drain writebuffer */

	/* ...and wait for ready bit */
	t = 100;
	while ((!(__raw_readl(AC97_STAT(pscdata)) & PSC_AC97STAT_DR)) && --t)
	msleep(1);

	if (!t)
	printk(KERN_ERR "PSC-AC97: can't enable!\n");

	mutex_unlock(&pscdata->lock);

	pscdata->cfg = r;
	pscdata->rate = params_rate(params);
	}

	out:
	return 0;
	}

	static int au1xpsc_ac97_trigger(struct snd_pcm_substream *substream,
	int cmd, struct snd_soc_dai *dai)
	{
	struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
	int ret, stype = substream->stream;

	ret = 0;

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
	case SNDRV_PCM_TRIGGER_RESUME:
	__raw_writel(AC97PCR_CLRFIFO(stype), AC97_PCR(pscdata));
	wmb(); /* drain writebuffer */
	__raw_writel(AC97PCR_START(stype), AC97_PCR(pscdata));
	wmb(); /* drain writebuffer */
	break;
	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	__raw_writel(AC97PCR_STOP(stype), AC97_PCR(pscdata));
	wmb(); /* drain writebuffer */

	while (__raw_readl(AC97_STAT(pscdata)) & AC97STAT_BUSY(stype))
	asm volatile ("nop");

	__raw_writel(AC97PCR_CLRFIFO(stype), AC97_PCR(pscdata));
	wmb(); /* drain writebuffer */

	break;
	default:
	ret = -EINVAL;
	}
	return ret;
	}

	static int au1xpsc_ac97_startup(struct snd_pcm_substream *substream,
	struct snd_soc_dai *dai)
	{
	struct au1xpsc_audio_data *pscdata = snd_soc_dai_get_drvdata(dai);
	snd_soc_dai_set_dma_data(dai, substream, &pscdata->dmaids[0]);
	return 0;
	}

	static int au1xpsc_ac97_probe(struct snd_soc_dai *dai)
	{
	return au1xpsc_ac97_workdata ? 0 : -ENODEV;
	}

	static const struct snd_soc_dai_ops au1xpsc_ac97_dai_ops = {
	.startup = au1xpsc_ac97_startup,
	.trigger = au1xpsc_ac97_trigger,
	.hw_params = au1xpsc_ac97_hw_params,
	};

	static const struct snd_soc_dai_driver au1xpsc_ac97_dai_template = {
	.bus_control = true,
	.probe = au1xpsc_ac97_probe,
	.playback = {
	.rates = AC97_RATES,
	.formats = AC97_FMTS,
	.channels_min = 2,
	.channels_max = 2,
	},
	.capture = {
	.rates = AC97_RATES,
	.formats = AC97_FMTS,
	.channels_min = 2,
	.channels_max = 2,
	},
	.ops = &au1xpsc_ac97_dai_ops,
	};

	static const struct snd_soc_component_driver au1xpsc_ac97_component = {
	.name = "au1xpsc-ac97",
	};

	static int au1xpsc_ac97_drvprobe(struct platform_device *pdev)
	{
	int ret;
	struct resource iores, dmares;
	unsigned long sel;
	struct au1xpsc_audio_data *wd;

	wd = devm_kzalloc(&pdev->dev, sizeof(struct au1xpsc_audio_data),
	GFP_KERNEL);
	if (!wd)
	return -ENOMEM;

	mutex_init(&wd->lock);

	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	wd->mmio = devm_ioremap_resource(&pdev->dev, iores);
	if (IS_ERR(wd->mmio))
	return PTR_ERR(wd->mmio);

	dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0);
	if (!dmares)
	return -EBUSY;
	wd->dmaids[SNDRV_PCM_STREAM_PLAYBACK] = dmares->start;

	dmares = platform_get_resource(pdev, IORESOURCE_DMA, 1);
	if (!dmares)
	return -EBUSY;
	wd->dmaids[SNDRV_PCM_STREAM_CAPTURE] = dmares->start;

	/* configuration: max dma trigger threshold, enable ac97 */
	wd->cfg = PSC_AC97CFG_RT_FIFO8 \| PSC_AC97CFG_TT_FIFO8 \|
	PSC_AC97CFG_DE_ENABLE;

	/* preserve PSC clock source set up by platform */
	sel = __raw_readl(PSC_SEL(wd)) & PSC_SEL_CLK_MASK;
	__raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
	wmb(); /* drain writebuffer */
	__raw_writel(0, PSC_SEL(wd));
	wmb(); /* drain writebuffer */
	__raw_writel(PSC_SEL_PS_AC97MODE \| sel, PSC_SEL(wd));
	wmb(); /* drain writebuffer */

	/* name the DAI like this device instance ("au1xpsc-ac97.PSCINDEX") */
	memcpy(&wd->dai_drv, &au1xpsc_ac97_dai_template,
	sizeof(struct snd_soc_dai_driver));
	wd->dai_drv.name = dev_name(&pdev->dev);

	platform_set_drvdata(pdev, wd);

	ret = snd_soc_set_ac97_ops(&psc_ac97_ops);
	if (ret)
	return ret;

	ret = snd_soc_register_component(&pdev->dev, &au1xpsc_ac97_component,
	&wd->dai_drv, 1);
	if (ret)
	return ret;

	au1xpsc_ac97_workdata = wd;
	return 0;
	}

	static int au1xpsc_ac97_drvremove(struct platform_device *pdev)
	{
	struct au1xpsc_audio_data *wd = platform_get_drvdata(pdev);

	snd_soc_unregister_component(&pdev->dev);

	/* disable PSC completely */
	__raw_writel(0, AC97_CFG(wd));
	wmb(); /* drain writebuffer */
	__raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
	wmb(); /* drain writebuffer */

	au1xpsc_ac97_workdata = NULL; /* MDEV */

	return 0;
	}

	#ifdef CONFIG_PM
	static int au1xpsc_ac97_drvsuspend(struct device *dev)
	{
	struct au1xpsc_audio_data *wd = dev_get_drvdata(dev);

	/* save interesting registers and disable PSC */
	wd->pm[0] = __raw_readl(PSC_SEL(wd));

	__raw_writel(0, AC97_CFG(wd));
	wmb(); /* drain writebuffer */
	__raw_writel(PSC_CTRL_DISABLE, PSC_CTRL(wd));
	wmb(); /* drain writebuffer */

	return 0;
	}

	static int au1xpsc_ac97_drvresume(struct device *dev)
	{
	struct au1xpsc_audio_data *wd = dev_get_drvdata(dev);

	/* restore PSC clock config */
	__raw_writel(wd->pm[0] \| PSC_SEL_PS_AC97MODE, PSC_SEL(wd));
	wmb(); /* drain writebuffer */

	/* after this point the ac97 core will cold-reset the codec.
	* During cold-reset the PSC is reinitialized and the last
	* configuration set up in hw_params() is restored.
	*/
	return 0;
	}

	static const struct dev_pm_ops au1xpscac97_pmops = {
	.suspend = au1xpsc_ac97_drvsuspend,
	.resume = au1xpsc_ac97_drvresume,
	};

	#define AU1XPSCAC97_PMOPS &au1xpscac97_pmops

	#else

	#define AU1XPSCAC97_PMOPS NULL

	#endif

	static struct platform_driver au1xpsc_ac97_driver = {
	.driver = {
	.name = "au1xpsc_ac97",
	.pm = AU1XPSCAC97_PMOPS,
	},
	.probe = au1xpsc_ac97_drvprobe,
	.remove = au1xpsc_ac97_drvremove,
	};

	module_platform_driver(au1xpsc_ac97_driver);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Au12x0/Au1550 PSC AC97 ALSA ASoC audio driver");
	MODULE_AUTHOR("Manuel Lauss");