[ALSA] ASoC Samsung S3C24xx audio DMA

This patch by Ben Dooks from Simtec Electronics adds ASoC audio DMA
support for the Samsung S3C24xx CPU.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Graeme Gregory <gg@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lg@opensource.wolfsonmicro.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 462 insertions, 0 deletions

diff --git a/sound/soc/s3c24xx/s3c24xx-pcm.c b/sound/soc/s3c24xx/s3c24xx-pcm.c
new file mode 100644
index 000000000000..f1c0b9fa179c
--- /dev/null
+++ b/sound/soc/s3c24xx/s3c24xx-pcm.c
@@ -0,0 +1,462 @@
+/*
+ * s3c24xx-pcm.c  --  ALSA Soc Audio Layer
+ *
+ * (c) 2006 Wolfson Microelectronics PLC.
+ * Graeme Gregory graeme.gregory@wolfsonmicro.com or linux@wolfsonmicro.com
+ *
+ * (c) 2004-2005 Simtec Electronics
+ *      http://armlinux.simtec.co.uk/
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ *
+ *  Revision history
+ *    11th Dec 2006   Merged with Simtec driver
+ *    10th Nov 2006   Initial version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_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 <sound/soc.h>
+
+#include <asm/dma.h>
+#include <asm/io.h>
+#include <asm/hardware.h>
+#include <asm/arch/dma.h>
+#include <asm/arch/audio.h>
+
+#include "s3c24xx-pcm.h"
+
+#define S3C24XX_PCM_DEBUG 0
+#if S3C24XX_PCM_DEBUG
+#define DBG(x...) printk(KERN_DEBUG x)
+#else
+#define DBG(x...)
+#endif
+
+static const struct snd_pcm_hardware s3c24xx_pcm_hardware = {
+        .info                   = SNDRV_PCM_INFO_INTERLEAVED |
+                                    SNDRV_PCM_INFO_BLOCK_TRANSFER |
+                                    SNDRV_PCM_INFO_MMAP |
+                                    SNDRV_PCM_INFO_MMAP_VALID,
+        .formats                = SNDRV_PCM_FMTBIT_S16_LE |
+                                    SNDRV_PCM_FMTBIT_U16_LE |
+                                    SNDRV_PCM_FMTBIT_U8 |
+                                    SNDRV_PCM_FMTBIT_S8,
+        .channels_min           = 2,
+        .channels_max           = 2,
+        .buffer_bytes_max       = 128*1024,
+        .period_bytes_min       = PAGE_SIZE,
+        .period_bytes_max       = PAGE_SIZE*2,
+        .periods_min            = 2,
+        .periods_max            = 128,
+        .fifo_size              = 32,
+};
+
+struct s3c24xx_runtime_data {
+        spinlock_t lock;
+        int state;
+        unsigned int dma_loaded;
+        unsigned int dma_limit;
+        unsigned int dma_period;
+        dma_addr_t dma_start;
+        dma_addr_t dma_pos;
+        dma_addr_t dma_end;
+        struct s3c24xx_pcm_dma_params *params;
+};
+
+/* s3c24xx_pcm_enqueue
+ *
+ * place a dma buffer onto the queue for the dma system
+ * to handle.
+*/
+static void s3c24xx_pcm_enqueue(struct snd_pcm_substream *substream)
+{
+        struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
+        dma_addr_t pos = prtd->dma_pos;
+        int ret;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        while ( prtd->dma_loaded < prtd->dma_limit) {
+                unsigned long len = prtd->dma_period;
+
+                DBG("dma_loaded: %d\n",prtd->dma_loaded);
+
+                if ((pos + len) > prtd->dma_end) {
+                        len  = prtd->dma_end - pos;
+                        DBG(KERN_DEBUG "%s: corrected dma len %ld\n",
+                               __FUNCTION__, len);
+                }
+
+                ret = s3c2410_dma_enqueue(prtd->params->channel, substream, pos, len);
+
+                if (ret == 0) {
+                        prtd->dma_loaded++;
+                        pos += prtd->dma_period;
+                        if (pos >= prtd->dma_end)
+                                pos = prtd->dma_start;
+                } else
+                        break;
+        }
+
+        prtd->dma_pos = pos;
+}
+
+static void s3c24xx_audio_buffdone(struct s3c2410_dma_chan *channel,
+                                                        void *dev_id, int size,
+                                                        enum s3c2410_dma_buffresult result)
+{
+        struct snd_pcm_substream *substream = dev_id;
+        struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        if (result == S3C2410_RES_ABORT || result == S3C2410_RES_ERR)
+                return;
+
+        if (substream)
+                snd_pcm_period_elapsed(substream);
+
+        spin_lock(&prtd->lock);
+        if (prtd->state & ST_RUNNING) {
+                prtd->dma_loaded--;
+                s3c24xx_pcm_enqueue(substream);
+        }
+
+        spin_unlock(&prtd->lock);
+}
+
+static int s3c24xx_pcm_hw_params(struct snd_pcm_substream *substream,
+        struct snd_pcm_hw_params *params)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct s3c24xx_runtime_data *prtd = runtime->private_data;
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+        struct s3c24xx_pcm_dma_params *dma = rtd->dai->cpu_dai->dma_data;
+        unsigned long totbytes = params_buffer_bytes(params);
+        int ret=0;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        /* return if this is a bufferless transfer e.g.
+         * codec <--> BT codec or GSM modem -- lg FIXME */
+        if (!dma)
+                return 0;
+
+        /* prepare DMA */
+        prtd->params = dma;
+
+        DBG("params %p, client %p, channel %d\n", prtd->params,
+                prtd->params->client, prtd->params->channel);
+
+        ret = s3c2410_dma_request(prtd->params->channel,
+                                  prtd->params->client, NULL);
+
+        if (ret) {
+                DBG(KERN_ERR "failed to get dma channel\n");
+                return ret;
+        }
+
+        /* channel needs configuring for mem=>device, increment memory addr,
+         * sync to pclk, half-word transfers to the IIS-FIFO. */
+        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+                s3c2410_dma_devconfig(prtd->params->channel,
+                                                S3C2410_DMASRC_MEM, S3C2410_DISRCC_INC |
+                                                S3C2410_DISRCC_APB, prtd->params->dma_addr);
+
+                s3c2410_dma_config(prtd->params->channel,
+                                                2, S3C2410_DCON_SYNC_PCLK | S3C2410_DCON_HANDSHAKE);
+        } else {
+                s3c2410_dma_config(prtd->params->channel,
+                                                2, S3C2410_DCON_HANDSHAKE | S3C2410_DCON_SYNC_PCLK);
+
+                s3c2410_dma_devconfig(prtd->params->channel,
+                                                S3C2410_DMASRC_HW, 0x3,
+                                                prtd->params->dma_addr);
+        }
+
+        s3c2410_dma_set_buffdone_fn(prtd->params->channel,
+                                    s3c24xx_audio_buffdone);
+
+        snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
+
+        runtime->dma_bytes = totbytes;
+
+        spin_lock_irq(&prtd->lock);
+        prtd->dma_loaded = 0;
+        prtd->dma_limit = runtime->hw.periods_min;
+        prtd->dma_period = params_period_bytes(params);
+        prtd->dma_start = runtime->dma_addr;
+        prtd->dma_pos = prtd->dma_start;
+        prtd->dma_end = prtd->dma_start + totbytes;
+        spin_unlock_irq(&prtd->lock);
+
+        return 0;
+}
+
+static int s3c24xx_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+        struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        /* TODO - do we need to ensure DMA flushed */
+        snd_pcm_set_runtime_buffer(substream, NULL);
+
+        if(prtd->params) {
+                s3c2410_dma_free(prtd->params->channel, prtd->params->client);
+                prtd->params = NULL;
+        }
+
+        return 0;
+}
+
+static int s3c24xx_pcm_prepare(struct snd_pcm_substream *substream)
+{
+        struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
+        int ret = 0;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        /* return if this is a bufferless transfer e.g.
+         * codec <--> BT codec or GSM modem -- lg FIXME */
+        if (!prtd->params)
+                return 0;
+
+        /* flush the DMA channel */
+        s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_FLUSH);
+        prtd->dma_loaded = 0;
+        prtd->dma_pos = prtd->dma_start;
+
+        /* enqueue dma buffers */
+        s3c24xx_pcm_enqueue(substream);
+
+        return ret;
+}
+
+static int s3c24xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+        struct s3c24xx_runtime_data *prtd = substream->runtime->private_data;
+        int ret = 0;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        spin_lock(&prtd->lock);
+
+        switch (cmd) {
+        case SNDRV_PCM_TRIGGER_START:
+        case SNDRV_PCM_TRIGGER_RESUME:
+        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+                prtd->state |= ST_RUNNING;
+                s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_START);
+                s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_STARTED);
+                break;
+
+        case SNDRV_PCM_TRIGGER_STOP:
+        case SNDRV_PCM_TRIGGER_SUSPEND:
+        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+                prtd->state &= ~ST_RUNNING;
+                s3c2410_dma_ctrl(prtd->params->channel, S3C2410_DMAOP_STOP);
+                break;
+
+        default:
+                ret = -EINVAL;
+                break;
+        }
+
+        spin_unlock(&prtd->lock);
+
+        return ret;
+}
+
+static snd_pcm_uframes_t s3c24xx_pcm_pointer(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct s3c24xx_runtime_data *prtd = runtime->private_data;
+        unsigned long res;
+        dma_addr_t src, dst;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        spin_lock(&prtd->lock);
+        s3c2410_dma_getposition(prtd->params->channel, &src, &dst);
+
+        if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
+                res = dst - prtd->dma_start;
+        else
+                res = src - prtd->dma_start;
+
+        spin_unlock(&prtd->lock);
+
+        DBG("Pointer %x %x\n",src,dst);
+
+        /* we seem to be getting the odd error from the pcm library due
+         * to out-of-bounds pointers. this is maybe due to the dma engine
+         * not having loaded the new values for the channel before being
+         * callled... (todo - fix )
+         */
+
+        if (res >= snd_pcm_lib_buffer_bytes(substream)) {
+                if (res == snd_pcm_lib_buffer_bytes(substream))
+                        res = 0;
+        }
+
+        return bytes_to_frames(substream->runtime, res);
+}
+
+static int s3c24xx_pcm_open(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct s3c24xx_runtime_data *prtd;
+
+        int ret;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        snd_soc_set_runtime_hwparams(substream, &s3c24xx_pcm_hardware);
+
+        prtd = kzalloc(sizeof(struct s3c24xx_runtime_data), GFP_KERNEL);
+        if (prtd == NULL)
+                return -ENOMEM;
+
+        runtime->private_data = prtd;
+        return 0;
+}
+
+static int s3c24xx_pcm_close(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct s3c24xx_runtime_data *prtd = runtime->private_data;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        if(prtd)
+                kfree(prtd);
+        else
+                DBG("s3c24xx_pcm_close called with prtd == NULL\n");
+
+        return 0;
+}
+
+static int s3c24xx_pcm_mmap(struct snd_pcm_substream *substream,
+        struct vm_area_struct *vma)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        return dma_mmap_writecombine(substream->pcm->card->dev, vma,
+                                     runtime->dma_area,
+                                     runtime->dma_addr,
+                                     runtime->dma_bytes);
+}
+
+static struct snd_pcm_ops s3c24xx_pcm_ops = {
+        .open           = s3c24xx_pcm_open,
+        .close          = s3c24xx_pcm_close,
+        .ioctl          = snd_pcm_lib_ioctl,
+        .hw_params      = s3c24xx_pcm_hw_params,
+        .hw_free        = s3c24xx_pcm_hw_free,
+        .prepare        = s3c24xx_pcm_prepare,
+        .trigger        = s3c24xx_pcm_trigger,
+        .pointer        = s3c24xx_pcm_pointer,
+        .mmap           = s3c24xx_pcm_mmap,
+};
+
+static int s3c24xx_pcm_preallocate_dma_buffer(struct snd_pcm *pcm, int stream)
+{
+        struct snd_pcm_substream *substream = pcm->streams[stream].substream;
+        struct snd_dma_buffer *buf = &substream->dma_buffer;
+        size_t size = s3c24xx_pcm_hardware.buffer_bytes_max;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        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 s3c24xx_pcm_free_dma_buffers(struct snd_pcm *pcm)
+{
+        struct snd_pcm_substream *substream;
+        struct snd_dma_buffer *buf;
+        int stream;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        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 s3c24xx_pcm_dmamask = DMA_32BIT_MASK;
+
+static int s3c24xx_pcm_new(struct snd_card *card, struct snd_soc_codec_dai *dai,
+        struct snd_pcm *pcm)
+{
+        int ret = 0;
+
+        DBG("Entered %s\n", __FUNCTION__);
+
+        if (!card->dev->dma_mask)
+                card->dev->dma_mask = &s3c24xx_pcm_dmamask;
+        if (!card->dev->coherent_dma_mask)
+                card->dev->coherent_dma_mask = 0xffffffff;
+
+        if (dai->playback.channels_min) {
+                ret = s3c24xx_pcm_preallocate_dma_buffer(pcm,
+                        SNDRV_PCM_STREAM_PLAYBACK);
+                if (ret)
+                        goto out;
+        }
+
+        if (dai->capture.channels_min) {
+                ret = s3c24xx_pcm_preallocate_dma_buffer(pcm,
+                        SNDRV_PCM_STREAM_CAPTURE);
+                if (ret)
+                        goto out;
+        }
+ out:
+        return ret;
+}
+
+struct snd_soc_platform s3c24xx_soc_platform = {
+        .name           = "s3c24xx-audio",
+        .pcm_ops        = &s3c24xx_pcm_ops,
+        .pcm_new        = s3c24xx_pcm_new,
+        .pcm_free       = s3c24xx_pcm_free_dma_buffers,
+};
+
+EXPORT_SYMBOL_GPL(s3c24xx_soc_platform);
+
+MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
+MODULE_DESCRIPTION("Samsung S3C24XX PCM DMA module");
+MODULE_LICENSE("GPL");