ASoC: add ep93xx AC97 audio driver

Add support for AC97 controllers found in Cirrus Logic EP93xx family SoCs.

Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/ep93xx/Kconfig

@@ -3,11 +3,16 @@ config SND_EP93XX_SOC
 	depends on ARCH_EP93XX && SND_SOC
 	help
 	  Say Y or M if you want to add support for codecs attached to
-	  the EP93xx I2S interface.
+	  the EP93xx I2S or AC97 interfaces.
 
 config SND_EP93XX_SOC_I2S
 	tristate
 
+config SND_EP93XX_SOC_AC97
+	tristate
+	select AC97_BUS
+	select SND_SOC_AC97_BUS
+
 config SND_EP93XX_SOC_SNAPPERCL15
         tristate "SoC Audio support for Bluewater Systems Snapper CL15 module"
         depends on SND_EP93XX_SOC && MACH_SNAPPER_CL15

sound/soc/ep93xx/Makefile

@@ -1,9 +1,11 @@
 # EP93xx Platform Support
 snd-soc-ep93xx-objs				:= ep93xx-pcm.o
 snd-soc-ep93xx-i2s-objs	 			:= ep93xx-i2s.o
+snd-soc-ep93xx-ac97-objs 			:= ep93xx-ac97.o
 
 obj-$(CONFIG_SND_EP93XX_SOC)			+= snd-soc-ep93xx.o
 obj-$(CONFIG_SND_EP93XX_SOC_I2S)		+= snd-soc-ep93xx-i2s.o
+obj-$(CONFIG_SND_EP93XX_SOC_AC97)		+= snd-soc-ep93xx-ac97.o
 
 # EP93XX Machine Support
 snd-soc-snappercl15-objs			:= snappercl15.o

sound/soc/ep93xx/ep93xx-ac97.c

@@ -0,0 +1,468 @@
+/*
+ * ASoC driver for Cirrus Logic EP93xx AC97 controller.
+ *
+ * Copyright (c) 2010 Mika Westerberg
+ *
+ * Based on s3c-ac97 ASoC driver by Jaswinder Singh.
+ *
+ * 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/delay.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <sound/core.h>
+#include <sound/ac97_codec.h>
+#include <sound/soc.h>
+
+#include <mach/dma.h>
+#include "ep93xx-pcm.h"
+
+/*
+ * Per channel (1-4) registers.
+ */
+#define AC97CH(n)		(((n) - 1) * 0x20)
+
+#define AC97DR(n)		(AC97CH(n) + 0x0000)
+
+#define AC97RXCR(n)		(AC97CH(n) + 0x0004)
+#define AC97RXCR_REN		BIT(0)
+#define AC97RXCR_RX3		BIT(3)
+#define AC97RXCR_RX4		BIT(4)
+#define AC97RXCR_CM		BIT(15)
+
+#define AC97TXCR(n)		(AC97CH(n) + 0x0008)
+#define AC97TXCR_TEN		BIT(0)
+#define AC97TXCR_TX3		BIT(3)
+#define AC97TXCR_TX4		BIT(4)
+#define AC97TXCR_CM		BIT(15)
+
+#define AC97SR(n)		(AC97CH(n) + 0x000c)
+#define AC97SR_TXFE		BIT(1)
+#define AC97SR_TXUE		BIT(6)
+
+#define AC97RISR(n)		(AC97CH(n) + 0x0010)
+#define AC97ISR(n)		(AC97CH(n) + 0x0014)
+#define AC97IE(n)		(AC97CH(n) + 0x0018)
+
+/*
+ * Global AC97 controller registers.
+ */
+#define AC97S1DATA		0x0080
+#define AC97S2DATA		0x0084
+#define AC97S12DATA		0x0088
+
+#define AC97RGIS		0x008c
+#define AC97GIS			0x0090
+#define AC97IM			0x0094
+/*
+ * Common bits for RGIS, GIS and IM registers.
+ */
+#define AC97_SLOT2RXVALID	BIT(1)
+#define AC97_CODECREADY		BIT(5)
+#define AC97_SLOT2TXCOMPLETE	BIT(6)
+
+#define AC97EOI			0x0098
+#define AC97EOI_WINT		BIT(0)
+#define AC97EOI_CODECREADY	BIT(1)
+
+#define AC97GCR			0x009c
+#define AC97GCR_AC97IFE		BIT(0)
+
+#define AC97RESET		0x00a0
+#define AC97RESET_TIMEDRESET	BIT(0)
+
+#define AC97SYNC		0x00a4
+#define AC97SYNC_TIMEDSYNC	BIT(0)
+
+#define AC97_TIMEOUT		msecs_to_jiffies(5)
+
+/**
+ * struct ep93xx_ac97_info - EP93xx AC97 controller info structure
+ * @lock: mutex serializing access to the bus (slot 1 & 2 ops)
+ * @dev: pointer to the platform device dev structure
+ * @mem: physical memory resource for the registers
+ * @regs: mapped AC97 controller registers
+ * @irq: AC97 interrupt number
+ * @done: bus ops wait here for an interrupt
+ */
+struct ep93xx_ac97_info {
+	struct mutex		lock;
+	struct device		*dev;
+	struct resource		*mem;
+	void __iomem		*regs;
+	int			irq;
+	struct completion	done;
+};
+
+/* currently ALSA only supports a single AC97 device */
+static struct ep93xx_ac97_info *ep93xx_ac97_info;
+
+static struct ep93xx_pcm_dma_params ep93xx_ac97_pcm_out = {
+	.name		= "ac97-pcm-out",
+	.dma_port	= EP93XX_DMA_M2P_PORT_AAC1,
+};
+
+static struct ep93xx_pcm_dma_params ep93xx_ac97_pcm_in = {
+	.name		= "ac97-pcm-in",
+	.dma_port	= EP93XX_DMA_M2P_PORT_AAC1,
+};
+
+static inline unsigned ep93xx_ac97_read_reg(struct ep93xx_ac97_info *info,
+					    unsigned reg)
+{
+	return __raw_readl(info->regs + reg);
+}
+
+static inline void ep93xx_ac97_write_reg(struct ep93xx_ac97_info *info,
+					 unsigned reg, unsigned val)
+{
+	__raw_writel(val, info->regs + reg);
+}
+
+static unsigned short ep93xx_ac97_read(struct snd_ac97 *ac97,
+				       unsigned short reg)
+{
+	struct ep93xx_ac97_info *info = ep93xx_ac97_info;
+	unsigned short val;
+
+	mutex_lock(&info->lock);
+
+	ep93xx_ac97_write_reg(info, AC97S1DATA, reg);
+	ep93xx_ac97_write_reg(info, AC97IM, AC97_SLOT2RXVALID);
+	if (!wait_for_completion_timeout(&info->done, AC97_TIMEOUT)) {
+		dev_warn(info->dev, "timeout reading register %x\n", reg);
+		mutex_unlock(&info->lock);
+		return -ETIMEDOUT;
+	}
+	val = (unsigned short)ep93xx_ac97_read_reg(info, AC97S2DATA);
+
+	mutex_unlock(&info->lock);
+	return val;
+}
+
+static void ep93xx_ac97_write(struct snd_ac97 *ac97,
+			      unsigned short reg,
+			      unsigned short val)
+{
+	struct ep93xx_ac97_info *info = ep93xx_ac97_info;
+
+	mutex_lock(&info->lock);
+
+	/*
+	 * Writes to the codec need to be done so that slot 2 is filled in
+	 * before slot 1.
+	 */
+	ep93xx_ac97_write_reg(info, AC97S2DATA, val);
+	ep93xx_ac97_write_reg(info, AC97S1DATA, reg);
+
+	ep93xx_ac97_write_reg(info, AC97IM, AC97_SLOT2TXCOMPLETE);
+	if (!wait_for_completion_timeout(&info->done, AC97_TIMEOUT))
+		dev_warn(info->dev, "timeout writing register %x\n", reg);
+
+	mutex_unlock(&info->lock);
+}
+
+static void ep93xx_ac97_warm_reset(struct snd_ac97 *ac97)
+{
+	struct ep93xx_ac97_info *info = ep93xx_ac97_info;
+
+	mutex_lock(&info->lock);
+
+	/*
+	 * We are assuming that before this functions gets called, the codec
+	 * BIT_CLK is stopped by forcing the codec into powerdown mode. We can
+	 * control the SYNC signal directly via AC97SYNC register. Using
+	 * TIMEDSYNC the controller will keep the SYNC high > 1us.
+	 */
+	ep93xx_ac97_write_reg(info, AC97SYNC, AC97SYNC_TIMEDSYNC);
+	ep93xx_ac97_write_reg(info, AC97IM, AC97_CODECREADY);
+	if (!wait_for_completion_timeout(&info->done, AC97_TIMEOUT))
+		dev_warn(info->dev, "codec warm reset timeout\n");
+
+	mutex_unlock(&info->lock);
+}
+
+static void ep93xx_ac97_cold_reset(struct snd_ac97 *ac97)
+{
+	struct ep93xx_ac97_info *info = ep93xx_ac97_info;
+
+	mutex_lock(&info->lock);
+
+	/*
+	 * For doing cold reset, we disable the AC97 controller interface, clear
+	 * WINT and CODECREADY bits, and finally enable the interface again.
+	 */
+	ep93xx_ac97_write_reg(info, AC97GCR, 0);
+	ep93xx_ac97_write_reg(info, AC97EOI, AC97EOI_CODECREADY | AC97EOI_WINT);
+	ep93xx_ac97_write_reg(info, AC97GCR, AC97GCR_AC97IFE);
+
+	/*
+	 * Now, assert the reset and wait for the codec to become ready.
+	 */
+	ep93xx_ac97_write_reg(info, AC97RESET, AC97RESET_TIMEDRESET);
+	ep93xx_ac97_write_reg(info, AC97IM, AC97_CODECREADY);
+	if (!wait_for_completion_timeout(&info->done, AC97_TIMEOUT))
+		dev_warn(info->dev, "codec cold reset timeout\n");
+
+	/*
+	 * Give the codec some time to come fully out from the reset. This way
+	 * we ensure that the subsequent reads/writes will work.
+	 */
+	usleep_range(15000, 20000);
+
+	mutex_unlock(&info->lock);
+}
+
+static irqreturn_t ep93xx_ac97_interrupt(int irq, void *dev_id)
+{
+	struct ep93xx_ac97_info *info = dev_id;
+	unsigned status, mask;
+
+	/*
+	 * Just mask out the interrupt and wake up the waiting thread.
+	 * Interrupts are cleared via reading/writing to slot 1 & 2 registers by
+	 * the waiting thread.
+	 */
+	status = ep93xx_ac97_read_reg(info, AC97GIS);
+	mask = ep93xx_ac97_read_reg(info, AC97IM);
+	mask &= ~status;
+	ep93xx_ac97_write_reg(info, AC97IM, mask);
+
+	complete(&info->done);
+	return IRQ_HANDLED;
+}
+
+struct snd_ac97_bus_ops soc_ac97_ops = {
+	.read		= ep93xx_ac97_read,
+	.write		= ep93xx_ac97_write,
+	.reset		= ep93xx_ac97_cold_reset,
+	.warm_reset	= ep93xx_ac97_warm_reset,
+};
+EXPORT_SYMBOL_GPL(soc_ac97_ops);
+
+static int ep93xx_ac97_trigger(struct snd_pcm_substream *substream,
+			       int cmd, struct snd_soc_dai *dai)
+{
+	struct ep93xx_ac97_info *info = snd_soc_dai_get_drvdata(dai);
+	unsigned v = 0;
+
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_RESUME:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+			/*
+			 * Enable compact mode, TX slots 3 & 4, and the TX FIFO
+			 * itself.
+			 */
+			v |= AC97TXCR_CM;
+			v |= AC97TXCR_TX3 | AC97TXCR_TX4;
+			v |= AC97TXCR_TEN;
+			ep93xx_ac97_write_reg(info, AC97TXCR(1), v);
+		} else {
+			/*
+			 * Enable compact mode, RX slots 3 & 4, and the RX FIFO
+			 * itself.
+			 */
+			v |= AC97RXCR_CM;
+			v |= AC97RXCR_RX3 | AC97RXCR_RX4;
+			v |= AC97RXCR_REN;
+			ep93xx_ac97_write_reg(info, AC97RXCR(1), v);
+		}
+		break;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_SUSPEND:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+			/*
+			 * As per Cirrus EP93xx errata described below:
+			 *
+			 * http://www.cirrus.com/en/pubs/errata/ER667E2B.pdf
+			 *
+			 * we will wait for the TX FIFO to be empty before
+			 * clearing the TEN bit.
+			 */
+			unsigned long timeout = jiffies + AC97_TIMEOUT;
+
+			do {
+				v = ep93xx_ac97_read_reg(info, AC97SR(1));
+				if (time_after(jiffies, timeout)) {
+					dev_warn(info->dev, "TX timeout\n");
+					break;
+				}
+			} while (!(v & (AC97SR_TXFE | AC97SR_TXUE)));
+
+			/* disable the TX FIFO */
+			ep93xx_ac97_write_reg(info, AC97TXCR(1), 0);
+		} else {
+			/* disable the RX FIFO */
+			ep93xx_ac97_write_reg(info, AC97RXCR(1), 0);
+		}
+		break;
+
+	default:
+		dev_warn(info->dev, "unknown command %d\n", cmd);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ep93xx_ac97_startup(struct snd_pcm_substream *substream,
+			       struct snd_soc_dai *dai)
+{
+	struct ep93xx_pcm_dma_params *dma_data;
+
+	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		dma_data = &ep93xx_ac97_pcm_out;
+	else
+		dma_data = &ep93xx_ac97_pcm_in;
+
+	snd_soc_dai_set_dma_data(dai, substream, dma_data);
+	return 0;
+}
+
+static struct snd_soc_dai_ops ep93xx_ac97_dai_ops = {
+	.startup	= ep93xx_ac97_startup,
+	.trigger	= ep93xx_ac97_trigger,
+};
+
+struct snd_soc_dai_driver ep93xx_ac97_dai = {
+	.name		= "ep93xx-ac97",
+	.id		= 0,
+	.ac97_control	= 1,
+	.playback	= {
+		.stream_name	= "AC97 Playback",
+		.channels_min	= 2,
+		.channels_max	= 2,
+		.rates		= SNDRV_PCM_RATE_8000_48000,
+		.formats	= SNDRV_PCM_FMTBIT_S16_LE,
+	},
+	.capture	= {
+		.stream_name	= "AC97 Capture",
+		.channels_min	= 2,
+		.channels_max	= 2,
+		.rates		= SNDRV_PCM_RATE_8000_48000,
+		.formats	= SNDRV_PCM_FMTBIT_S16_LE,
+	},
+	.ops			= &ep93xx_ac97_dai_ops,
+};
+
+static int __devinit ep93xx_ac97_probe(struct platform_device *pdev)
+{
+	struct ep93xx_ac97_info *info;
+	int ret;
+
+	info = kzalloc(sizeof(struct ep93xx_ac97_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	dev_set_drvdata(&pdev->dev, info);
+
+	mutex_init(&info->lock);
+	init_completion(&info->done);
+	info->dev = &pdev->dev;
+
+	info->mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!info->mem) {
+		ret = -ENXIO;
+		goto fail_free_info;
+	}
+
+	info->irq = platform_get_irq(pdev, 0);
+	if (!info->irq) {
+		ret = -ENXIO;
+		goto fail_free_info;
+	}
+
+	if (!request_mem_region(info->mem->start, resource_size(info->mem),
+				pdev->name)) {
+		ret = -EBUSY;
+		goto fail_free_info;
+	}
+
+	info->regs = ioremap(info->mem->start, resource_size(info->mem));
+	if (!info->regs) {
+		ret = -ENOMEM;
+		goto fail_release_mem;
+	}
+
+	ret = request_irq(info->irq, ep93xx_ac97_interrupt, IRQF_TRIGGER_HIGH,
+			  pdev->name, info);
+	if (ret)
+		goto fail_unmap_mem;
+
+	ep93xx_ac97_info = info;
+	platform_set_drvdata(pdev, info);
+
+	ret = snd_soc_register_dai(&pdev->dev, &ep93xx_ac97_dai);
+	if (ret)
+		goto fail_free_irq;
+
+	return 0;
+
+fail_free_irq:
+	platform_set_drvdata(pdev, NULL);
+	free_irq(info->irq, info);
+fail_unmap_mem:
+	iounmap(info->regs);
+fail_release_mem:
+	release_mem_region(info->mem->start, resource_size(info->mem));
+fail_free_info:
+	kfree(info);
+
+	return ret;
+}
+
+static int __devexit ep93xx_ac97_remove(struct platform_device *pdev)
+{
+	struct ep93xx_ac97_info	*info = platform_get_drvdata(pdev);
+
+	snd_soc_unregister_dai(&pdev->dev);
+
+	/* disable the AC97 controller */
+	ep93xx_ac97_write_reg(info, AC97GCR, 0);
+
+	free_irq(info->irq, info);
+	iounmap(info->regs);
+	release_mem_region(info->mem->start, resource_size(info->mem));
+	platform_set_drvdata(pdev, NULL);
+	kfree(info);
+
+	return 0;
+}
+
+static struct platform_driver ep93xx_ac97_driver = {
+	.probe	= ep93xx_ac97_probe,
+	.remove	= __devexit_p(ep93xx_ac97_remove),
+	.driver = {
+		.name = "ep93xx-ac97",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init ep93xx_ac97_init(void)
+{
+	return platform_driver_register(&ep93xx_ac97_driver);
+}
+module_init(ep93xx_ac97_init);
+
+static void __exit ep93xx_ac97_exit(void)
+{
+	platform_driver_unregister(&ep93xx_ac97_driver);
+}
+module_exit(ep93xx_ac97_exit);
+
+MODULE_DESCRIPTION("EP93xx AC97 ASoC Driver");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:ep93xx-ac97");