/*
   * Au1000/Au1500/Au1100 AC97C controller driver for ASoC
   *
   * (c) 2011 Manuel Lauss <manuel.lauss@googlemail.com>
   *
   * based on the old ALSA driver originally written by
   *			Charles Eidsness <charles@cooper-street.com>
   */
  
  #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/platform_device.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 "psc.h"
  
  /* register offsets and bits */
  #define AC97_CONFIG	0x00
  #define AC97_STATUS	0x04
  #define AC97_DATA	0x08
  #define AC97_CMDRESP	0x0c
  #define AC97_ENABLE	0x10
  
  #define CFG_RC(x)	(((x) & 0x3ff) << 13)	/* valid rx slots mask */
  #define CFG_XS(x)	(((x) & 0x3ff) << 3)	/* valid tx slots mask */
  #define CFG_SG		(1 << 2)	/* sync gate */
  #define CFG_SN		(1 << 1)	/* sync control */
  #define CFG_RS		(1 << 0)	/* acrst# control */
  #define STAT_XU		(1 << 11)	/* tx underflow */
  #define STAT_XO		(1 << 10)	/* tx overflow */
  #define STAT_RU		(1 << 9)	/* rx underflow */
  #define STAT_RO		(1 << 8)	/* rx overflow */
  #define STAT_RD		(1 << 7)	/* codec ready */
  #define STAT_CP		(1 << 6)	/* command pending */
  #define STAT_TE		(1 << 4)	/* tx fifo empty */
  #define STAT_TF		(1 << 3)	/* tx fifo full */
  #define STAT_RE		(1 << 1)	/* rx fifo empty */
  #define STAT_RF		(1 << 0)	/* rx fifo full */
  #define CMD_SET_DATA(x)	(((x) & 0xffff) << 16)
  #define CMD_GET_DATA(x)	((x) & 0xffff)
  #define CMD_READ	(1 << 7)
  #define CMD_WRITE	(0 << 7)
  #define CMD_IDX(x)	((x) & 0x7f)
  #define EN_D		(1 << 1)	/* DISable bit */
  #define EN_CE		(1 << 0)	/* clock enable bit */
  
  /* how often to retry failed codec register reads/writes */
  #define AC97_RW_RETRIES	5
  
  #define AC97_RATES	\
  	SNDRV_PCM_RATE_CONTINUOUS
  
  #define AC97_FMTS	\
  	(SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S16_BE)
  
  /* instance data. There can be only one, MacLeod!!!!, fortunately there IS only
   * once AC97C on early Alchemy chips. The newer ones aren't so lucky.
   */
  static struct au1xpsc_audio_data *ac97c_workdata;
  #define ac97_to_ctx(x)		ac97c_workdata
  
  static inline unsigned long RD(struct au1xpsc_audio_data *ctx, int reg)
  {
  	return __raw_readl(ctx->mmio + reg);
  }
  
  static inline void WR(struct au1xpsc_audio_data *ctx, int reg, unsigned long v)
  {
  	__raw_writel(v, ctx->mmio + reg);
  	wmb();
  }
  
  static unsigned short au1xac97c_ac97_read(struct snd_ac97 *ac97,
  					  unsigned short r)
  {
  	struct au1xpsc_audio_data *ctx = ac97_to_ctx(ac97);
  	unsigned int tmo, retry;
  	unsigned long data;
  
  	data = ~0;
  	retry = AC97_RW_RETRIES;
  	do {
  		mutex_lock(&ctx->lock);
  
  		tmo = 5;
  		while ((RD(ctx, AC97_STATUS) & STAT_CP) && tmo--)
  			udelay(21);	/* wait an ac97 frame time */
  		if (!tmo) {
  			pr_debug("ac97rd timeout #1
  ");
  			goto next;
  		}
  
  		WR(ctx, AC97_CMDRESP, CMD_IDX(r) | CMD_READ);
  
  		/* stupid errata: data is only valid for 21us, so
  		 * poll, Forrest, poll...
  		 */
  		tmo = 0x10000;
  		while ((RD(ctx, AC97_STATUS) & STAT_CP) && tmo--)
  			asm volatile ("nop");
  		data = RD(ctx, AC97_CMDRESP);
  
  		if (!tmo)
  			pr_debug("ac97rd timeout #2
  ");
  
  next:
  		mutex_unlock(&ctx->lock);
  	} while (--retry && !tmo);
  
  	pr_debug("AC97RD %04x %04lx %d
  ", r, data, retry);
  
  	return retry ? data & 0xffff : 0xffff;
  }
  
  static void au1xac97c_ac97_write(struct snd_ac97 *ac97, unsigned short r,
  				 unsigned short v)
  {
  	struct au1xpsc_audio_data *ctx = ac97_to_ctx(ac97);
  	unsigned int tmo, retry;
  
  	retry = AC97_RW_RETRIES;
  	do {
  		mutex_lock(&ctx->lock);
  
  		for (tmo = 5; (RD(ctx, AC97_STATUS) & STAT_CP) && tmo; tmo--)
  			udelay(21);
  		if (!tmo) {
  			pr_debug("ac97wr timeout #1
  ");
  			goto next;
  		}
  
  		WR(ctx, AC97_CMDRESP, CMD_WRITE | CMD_IDX(r) | CMD_SET_DATA(v));
  
  		for (tmo = 10; (RD(ctx, AC97_STATUS) & STAT_CP) && tmo; tmo--)
  			udelay(21);
  		if (!tmo)
  			pr_debug("ac97wr timeout #2
  ");
  next:
  		mutex_unlock(&ctx->lock);
  	} while (--retry && !tmo);
  
  	pr_debug("AC97WR %04x %04x %d
  ", r, v, retry);
  }
  
  static void au1xac97c_ac97_warm_reset(struct snd_ac97 *ac97)
  {
  	struct au1xpsc_audio_data *ctx = ac97_to_ctx(ac97);
  
  	WR(ctx, AC97_CONFIG, ctx->cfg | CFG_SG | CFG_SN);
  	msleep(20);
  	WR(ctx, AC97_CONFIG, ctx->cfg | CFG_SG);
  	WR(ctx, AC97_CONFIG, ctx->cfg);
  }
  
  static void au1xac97c_ac97_cold_reset(struct snd_ac97 *ac97)
  {
  	struct au1xpsc_audio_data *ctx = ac97_to_ctx(ac97);
  	int i;
  
  	WR(ctx, AC97_CONFIG, ctx->cfg | CFG_RS);
  	msleep(500);
  	WR(ctx, AC97_CONFIG, ctx->cfg);
  
  	/* wait for codec ready */
  	i = 50;
  	while (((RD(ctx, AC97_STATUS) & STAT_RD) == 0) && --i)
  		msleep(20);
  	if (!i)
  		printk(KERN_ERR "ac97c: codec not ready after cold reset
  ");
  }
  
  /* AC97 controller operations */
  static struct snd_ac97_bus_ops ac97c_bus_ops = {
  	.read		= au1xac97c_ac97_read,
  	.write		= au1xac97c_ac97_write,
  	.reset		= au1xac97c_ac97_cold_reset,
  	.warm_reset	= au1xac97c_ac97_warm_reset,
  };
  
  static int alchemy_ac97c_startup(struct snd_pcm_substream *substream,
  				 struct snd_soc_dai *dai)
  {
  	struct au1xpsc_audio_data *ctx = snd_soc_dai_get_drvdata(dai);
  	snd_soc_dai_set_dma_data(dai, substream, &ctx->dmaids[0]);
  	return 0;
  }
  
  static const struct snd_soc_dai_ops alchemy_ac97c_ops = {
  	.startup		= alchemy_ac97c_startup,
  };
  
  static int au1xac97c_dai_probe(struct snd_soc_dai *dai)
  {
  	return ac97c_workdata ? 0 : -ENODEV;
  }
  
  static struct snd_soc_dai_driver au1xac97c_dai_driver = {
  	.name			= "alchemy-ac97c",
  	.ac97_control		= 1,
  	.probe			= au1xac97c_dai_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			= &alchemy_ac97c_ops,
  };
  
  static const struct snd_soc_component_driver au1xac97c_component = {
  	.name		= "au1xac97c",
  };
  
  static int au1xac97c_drvprobe(struct platform_device *pdev)
  {
  	int ret;
  	struct resource *iores, *dmares;
  	struct au1xpsc_audio_data *ctx;
  
  	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
  	if (!ctx)
  		return -ENOMEM;
  
  	mutex_init(&ctx->lock);
  
  	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!iores)
  		return -ENODEV;
  
  	if (!devm_request_mem_region(&pdev->dev, iores->start,
  				     resource_size(iores),
  				     pdev->name))
  		return -EBUSY;
  
  	ctx->mmio = devm_ioremap_nocache(&pdev->dev, iores->start,
  					 resource_size(iores));
  	if (!ctx->mmio)
  		return -EBUSY;
  
  	dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0);
  	if (!dmares)
  		return -EBUSY;
  	ctx->dmaids[SNDRV_PCM_STREAM_PLAYBACK] = dmares->start;
  
  	dmares = platform_get_resource(pdev, IORESOURCE_DMA, 1);
  	if (!dmares)
  		return -EBUSY;
  	ctx->dmaids[SNDRV_PCM_STREAM_CAPTURE] = dmares->start;
  
  	/* switch it on */
  	WR(ctx, AC97_ENABLE, EN_D | EN_CE);
  	WR(ctx, AC97_ENABLE, EN_CE);
  
  	ctx->cfg = CFG_RC(3) | CFG_XS(3);
  	WR(ctx, AC97_CONFIG, ctx->cfg);
  
  	platform_set_drvdata(pdev, ctx);
  
  	ret = snd_soc_set_ac97_ops(&ac97c_bus_ops);
  	if (ret)
  		return ret;
  
  	ret = snd_soc_register_component(&pdev->dev, &au1xac97c_component,
  					 &au1xac97c_dai_driver, 1);
  	if (ret)
  		return ret;
  
  	ac97c_workdata = ctx;
  	return 0;
  }
  
  static int au1xac97c_drvremove(struct platform_device *pdev)
  {
  	struct au1xpsc_audio_data *ctx = platform_get_drvdata(pdev);
  
  	snd_soc_unregister_component(&pdev->dev);
  
  	WR(ctx, AC97_ENABLE, EN_D);	/* clock off, disable */
  
  	ac97c_workdata = NULL;	/* MDEV */
  
  	return 0;
  }
  
  #ifdef CONFIG_PM
  static int au1xac97c_drvsuspend(struct device *dev)
  {
  	struct au1xpsc_audio_data *ctx = dev_get_drvdata(dev);
  
  	WR(ctx, AC97_ENABLE, EN_D);	/* clock off, disable */
  
  	return 0;
  }
  
  static int au1xac97c_drvresume(struct device *dev)
  {
  	struct au1xpsc_audio_data *ctx = dev_get_drvdata(dev);
  
  	WR(ctx, AC97_ENABLE, EN_D | EN_CE);
  	WR(ctx, AC97_ENABLE, EN_CE);
  	WR(ctx, AC97_CONFIG, ctx->cfg);
  
  	return 0;
  }
  
  static const struct dev_pm_ops au1xpscac97_pmops = {
  	.suspend	= au1xac97c_drvsuspend,
  	.resume		= au1xac97c_drvresume,
  };
  
  #define AU1XPSCAC97_PMOPS (&au1xpscac97_pmops)
  
  #else
  
  #define AU1XPSCAC97_PMOPS NULL
  
  #endif
  
  static struct platform_driver au1xac97c_driver = {
  	.driver	= {
  		.name	= "alchemy-ac97c",
  		.owner	= THIS_MODULE,
  		.pm	= AU1XPSCAC97_PMOPS,
  	},
  	.probe		= au1xac97c_drvprobe,
  	.remove		= au1xac97c_drvremove,
  };
  
  module_platform_driver(au1xac97c_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Au1000/1500/1100 AC97C ASoC driver");
  MODULE_AUTHOR("Manuel Lauss");