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>

3 files changed, 476 insertions, 1 deletions

diff --git a/sound/soc/ep93xx/Kconfig b/sound/soc/ep93xx/Kconfig
index f617f560f46b..108e5ff3ffc2 100644
--- a/sound/soc/ep93xx/Kconfig
+++ b/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
diff --git a/sound/soc/ep93xx/Makefile b/sound/soc/ep93xx/Makefile
index 272e60f57b9a..ac06e0092f95 100644
--- a/sound/soc/ep93xx/Makefile
+++ b/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
diff --git a/sound/soc/ep93xx/ep93xx-ac97.c b/sound/soc/ep93xx/ep93xx-ac97.c
new file mode 100644
index 000000000000..68a0bae1208a
--- /dev/null
+++ b/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");