ASoC: add DMA platform driver for MX1x and MX2x

This adds support for DMA platform valid for i.MX1 and i.MX2 platforms.

This is not valid for i.MX3 since it doesn't share the same DMA
interface than i.MX1 and i.MX2.

It has been tested on i.MX27 board.

Signed-off-by: Javier Martin <javier.martin@vista-silicon.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 487 insertions, 0 deletions

diff --git a/sound/soc/imx/mx1_mx2-pcm.c b/sound/soc/imx/mx1_mx2-pcm.c
new file mode 100644
index 000000000000..94807f844131
--- /dev/null
+++ b/sound/soc/imx/mx1_mx2-pcm.c
@@ -0,0 +1,487 @@
+/*
+ * mx1_mx2-pcm.c -- ALSA SoC interface for Freescale i.MX1x, i.MX2x CPUs
+ *
+ * Copyright 2009 Vista Silicon S.L.
+ * Author: Javier Martin
+ *         javier.martin@vista-silicon.com
+ *
+ * Based on mxc-pcm.c by Liam Girdwood.
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/dma-mapping.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <asm/dma.h>
+#include <mach/hardware.h>
+#include <mach/dma-mx1-mx2.h>
+
+#include "mx1_mx2-pcm.h"
+
+
+static const struct snd_pcm_hardware mx1_mx2_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,
+        .buffer_bytes_max       = 32 * 1024,
+        .period_bytes_min       = 64,
+        .period_bytes_max       = 8 * 1024,
+        .periods_min            = 2,
+        .periods_max            = 255,
+        .fifo_size              = 0,
+};
+
+struct mx1_mx2_runtime_data {
+        int dma_ch;
+        int active;
+        unsigned int period;
+        unsigned int periods;
+        int tx_spin;
+        spinlock_t dma_lock;
+        struct mx1_mx2_pcm_dma_params *dma_params;
+};
+
+
+/**
+  * This function stops the current dma transfer for playback
+  * and clears the dma pointers.
+  *
+  * @param      substream       pointer to the structure of the current stream.
+  *
+  */
+static int audio_stop_dma(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct mx1_mx2_runtime_data *prtd = runtime->private_data;
+        unsigned long flags;
+
+        spin_lock_irqsave(&prtd->dma_lock, flags);
+
+        pr_debug("%s\n", __func__);
+
+        prtd->active = 0;
+        prtd->period = 0;
+        prtd->periods = 0;
+
+        /* this stops the dma channel and clears the buffer ptrs */
+
+        imx_dma_disable(prtd->dma_ch);
+
+        spin_unlock_irqrestore(&prtd->dma_lock, flags);
+
+        return 0;
+}
+
+/**
+  * This function is called whenever a new audio block needs to be
+  * transferred to the codec. The function receives the address and the size
+  * of the new block and start a new DMA transfer.
+  *
+  * @param      substream       pointer to the structure of the current stream.
+  *
+  */
+static int dma_new_period(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime =  substream->runtime;
+        struct mx1_mx2_runtime_data *prtd = runtime->private_data;
+        unsigned int dma_size;
+        unsigned int offset;
+        int ret = 0;
+        dma_addr_t mem_addr;
+        unsigned int dev_addr;
+
+        if (prtd->active) {
+                dma_size = frames_to_bytes(runtime, runtime->period_size);
+                offset = dma_size * prtd->period;
+
+                pr_debug("%s: period (%d) out of (%d)\n", __func__,
+                        prtd->period,
+                        runtime->periods);
+                pr_debug("period_size %d frames\n offset %d bytes\n",
+                        (unsigned int)runtime->period_size,
+                        offset);
+                pr_debug("dma_size %d bytes\n", dma_size);
+
+                snd_BUG_ON(dma_size > mx1_mx2_pcm_hardware.period_bytes_max);
+
+                mem_addr = (dma_addr_t)(runtime->dma_addr + offset);
+                dev_addr = prtd->dma_params->per_address;
+                pr_debug("%s: mem_addr is %x\n dev_addr is %x\n",
+                                 __func__, mem_addr, dev_addr);
+
+                ret = imx_dma_setup_single(prtd->dma_ch, mem_addr,
+                                        dma_size, dev_addr,
+                                        prtd->dma_params->transfer_type);
+                if (ret < 0) {
+                        printk(KERN_ERR "Error configuring DMA\n");
+                        return ret;
+                }
+                imx_dma_enable(prtd->dma_ch);
+
+                pr_debug("%s: transfer enabled\nmem_addr = %x\n",
+                        __func__, (unsigned int) mem_addr);
+                pr_debug("dev_addr = %x\ndma_size = %d\n",
+                        (unsigned int) dev_addr, dma_size);
+
+                prtd->tx_spin = 1; /* FGA little trick to retrieve DMA pos */
+                prtd->period++;
+                prtd->period %= runtime->periods;
+    }
+        return ret;
+}
+
+
+/**
+  * This is a callback which will be called
+  * when a TX transfer finishes. The call occurs
+  * in interrupt context.
+  *
+  * @param      dat     pointer to the structure of the current stream.
+  *
+  */
+static void audio_dma_irq(int channel, void *data)
+{
+        struct snd_pcm_substream *substream;
+        struct snd_pcm_runtime *runtime;
+        struct mx1_mx2_runtime_data *prtd;
+        unsigned int dma_size;
+        unsigned int previous_period;
+        unsigned int offset;
+
+        substream = data;
+        runtime = substream->runtime;
+        prtd = runtime->private_data;
+        previous_period  = prtd->periods;
+        dma_size = frames_to_bytes(runtime, runtime->period_size);
+        offset = dma_size * previous_period;
+
+        prtd->tx_spin = 0;
+        prtd->periods++;
+        prtd->periods %= runtime->periods;
+
+        pr_debug("%s: irq per %d offset %x\n", __func__, prtd->periods, offset);
+
+        /*
+          * If we are getting a callback for an active stream then we inform
+          * the PCM middle layer we've finished a period
+          */
+        if (prtd->active)
+                snd_pcm_period_elapsed(substream);
+
+        /*
+          * Trig next DMA transfer
+          */
+        dma_new_period(substream);
+}
+
+/**
+  * This function configures the hardware to allow audio
+  * playback operations. It is called by ALSA framework.
+  *
+  * @param      substream       pointer to the structure of the current stream.
+  *
+  * @return              0 on success, -1 otherwise.
+  */
+static int
+snd_mx1_mx2_prepare(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime =  substream->runtime;
+        struct mx1_mx2_runtime_data *prtd = runtime->private_data;
+
+        prtd->period = 0;
+        prtd->periods = 0;
+
+        return 0;
+}
+
+static int mx1_mx2_pcm_hw_params(struct snd_pcm_substream *substream,
+        struct snd_pcm_hw_params *hw_params)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        int ret;
+
+        ret = snd_pcm_lib_malloc_pages(substream,
+                                        params_buffer_bytes(hw_params));
+        if (ret < 0) {
+                printk(KERN_ERR "%s: failed to malloc pcm pages\n", __func__);
+                return ret;
+        }
+
+        pr_debug("%s: snd_imx1_mx2_audio_hw_params runtime->dma_addr 0x(%x)\n",
+                __func__, (unsigned int)runtime->dma_addr);
+        pr_debug("%s: snd_imx1_mx2_audio_hw_params runtime->dma_area 0x(%x)\n",
+                __func__, (unsigned int)runtime->dma_area);
+        pr_debug("%s: snd_imx1_mx2_audio_hw_params runtime->dma_bytes 0x(%x)\n",
+                __func__, (unsigned int)runtime->dma_bytes);
+
+        return ret;
+}
+
+static int mx1_mx2_pcm_hw_free(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct mx1_mx2_runtime_data *prtd = runtime->private_data;
+
+        imx_dma_free(prtd->dma_ch);
+
+        snd_pcm_lib_free_pages(substream);
+
+        return 0;
+}
+
+static int mx1_mx2_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
+{
+        struct mx1_mx2_runtime_data *prtd = substream->runtime->private_data;
+        int ret = 0;
+
+        switch (cmd) {
+        case SNDRV_PCM_TRIGGER_START:
+                prtd->tx_spin = 0;
+                /* requested stream startup */
+                prtd->active = 1;
+                pr_debug("%s: starting dma_new_period\n", __func__);
+                ret = dma_new_period(substream);
+                break;
+        case SNDRV_PCM_TRIGGER_STOP:
+                /* requested stream shutdown */
+                pr_debug("%s: stopping dma transfer\n", __func__);
+                ret = audio_stop_dma(substream);
+                break;
+        default:
+                ret = -EINVAL;
+                break;
+        }
+
+        return ret;
+}
+
+static snd_pcm_uframes_t
+mx1_mx2_pcm_pointer(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct mx1_mx2_runtime_data *prtd = runtime->private_data;
+        unsigned int offset = 0;
+
+        /* tx_spin value is used here to check if a transfer is active */
+        if (prtd->tx_spin) {
+                offset = (runtime->period_size * (prtd->periods)) +
+                                                (runtime->period_size >> 1);
+                if (offset >= runtime->buffer_size)
+                        offset = runtime->period_size >> 1;
+        } else {
+                offset = (runtime->period_size * (prtd->periods));
+                if (offset >= runtime->buffer_size)
+                        offset = 0;
+        }
+        pr_debug("%s: pointer offset %x\n", __func__, offset);
+
+        return offset;
+}
+
+static int mx1_mx2_pcm_open(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct mx1_mx2_runtime_data *prtd;
+        struct snd_soc_pcm_runtime *rtd = substream->private_data;
+        struct mx1_mx2_pcm_dma_params *dma_data = rtd->dai->cpu_dai->dma_data;
+        int ret;
+
+        snd_soc_set_runtime_hwparams(substream, &mx1_mx2_pcm_hardware);
+
+        ret = snd_pcm_hw_constraint_integer(runtime,
+                                        SNDRV_PCM_HW_PARAM_PERIODS);
+        if (ret < 0)
+                return ret;
+
+        prtd = kzalloc(sizeof(struct mx1_mx2_runtime_data), GFP_KERNEL);
+        if (prtd == NULL) {
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        runtime->private_data = prtd;
+
+        if (!dma_data)
+                return -ENODEV;
+
+        prtd->dma_params = dma_data;
+
+        pr_debug("%s: Requesting dma channel (%s)\n", __func__,
+                                                prtd->dma_params->name);
+        prtd->dma_ch = imx_dma_request_by_prio(prtd->dma_params->name,
+                                                DMA_PRIO_HIGH);
+        if (prtd->dma_ch < 0) {
+                printk(KERN_ERR "Error requesting dma channel\n");
+                return ret;
+        }
+        imx_dma_config_burstlen(prtd->dma_ch,
+                                prtd->dma_params->watermark_level);
+
+        ret = imx_dma_config_channel(prtd->dma_ch,
+                        prtd->dma_params->per_config,
+                        prtd->dma_params->mem_config,
+                        prtd->dma_params->event_id, 0);
+
+        if (ret) {
+                pr_debug(KERN_ERR "Error configuring dma channel %d\n",
+                        prtd->dma_ch);
+                return ret;
+        }
+
+        pr_debug("%s: Setting tx dma callback function\n", __func__);
+        ret = imx_dma_setup_handlers(prtd->dma_ch,
+                                audio_dma_irq, NULL,
+                                (void *)substream);
+        if (ret < 0) {
+                printk(KERN_ERR "Error setting dma callback function\n");
+                return ret;
+        }
+        return 0;
+
+ out:
+        return ret;
+}
+
+static int mx1_mx2_pcm_close(struct snd_pcm_substream *substream)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        struct mx1_mx2_runtime_data *prtd = runtime->private_data;
+
+        kfree(prtd);
+
+        return 0;
+}
+
+static int mx1_mx2_pcm_mmap(struct snd_pcm_substream *substream,
+                                struct vm_area_struct *vma)
+{
+        struct snd_pcm_runtime *runtime = substream->runtime;
+        return dma_mmap_writecombine(substream->pcm->card->dev, vma,
+                                     runtime->dma_area,
+                                     runtime->dma_addr,
+                                     runtime->dma_bytes);
+}
+
+struct snd_pcm_ops mx1_mx2_pcm_ops = {
+        .open           = mx1_mx2_pcm_open,
+        .close          = mx1_mx2_pcm_close,
+        .ioctl          = snd_pcm_lib_ioctl,
+        .hw_params      = mx1_mx2_pcm_hw_params,
+        .hw_free        = mx1_mx2_pcm_hw_free,
+        .prepare        = snd_mx1_mx2_prepare,
+        .trigger        = mx1_mx2_pcm_trigger,
+        .pointer        = mx1_mx2_pcm_pointer,
+        .mmap           = mx1_mx2_pcm_mmap,
+};
+
+static u64 mx1_mx2_pcm_dmamask = 0xffffffff;
+
+static int mx1_mx2_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 = mx1_mx2_pcm_hardware.buffer_bytes_max;
+        buf->dev.type = SNDRV_DMA_TYPE_DEV;
+        buf->dev.dev = pcm->card->dev;
+        buf->private_data = NULL;
+
+        /* Reserve uncached-buffered memory area for DMA */
+        buf->area = dma_alloc_writecombine(pcm->card->dev, size,
+                                           &buf->addr, GFP_KERNEL);
+
+        pr_debug("%s: preallocate_dma_buffer: area=%p, addr=%p, size=%d\n",
+                __func__, (void *) buf->area, (void *) buf->addr, size);
+
+        if (!buf->area)
+                return -ENOMEM;
+
+        buf->bytes = size;
+        return 0;
+}
+
+static void mx1_mx2_pcm_free_dma_buffers(struct snd_pcm *pcm)
+{
+        struct snd_pcm_substream *substream;
+        struct snd_dma_buffer *buf;
+        int stream;
+
+        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;
+        }
+}
+
+int mx1_mx2_pcm_new(struct snd_card *card, struct snd_soc_dai *dai,
+        struct snd_pcm *pcm)
+{
+        int ret = 0;
+
+        if (!card->dev->dma_mask)
+                card->dev->dma_mask = &mx1_mx2_pcm_dmamask;
+        if (!card->dev->coherent_dma_mask)
+                card->dev->coherent_dma_mask = 0xffffffff;
+
+        if (dai->playback.channels_min) {
+                ret = mx1_mx2_pcm_preallocate_dma_buffer(pcm,
+                        SNDRV_PCM_STREAM_PLAYBACK);
+                pr_debug("%s: preallocate playback buffer\n", __func__);
+                if (ret)
+                        goto out;
+        }
+
+        if (dai->capture.channels_min) {
+                ret = mx1_mx2_pcm_preallocate_dma_buffer(pcm,
+                        SNDRV_PCM_STREAM_CAPTURE);
+                pr_debug("%s: preallocate capture buffer\n", __func__);
+                if (ret)
+                        goto out;
+        }
+ out:
+        return ret;
+}
+
+struct snd_soc_platform mx1_mx2_soc_platform = {
+        .name           = "mx1_mx2-audio",
+        .pcm_ops        = &mx1_mx2_pcm_ops,
+        .pcm_new        = mx1_mx2_pcm_new,
+        .pcm_free       = mx1_mx2_pcm_free_dma_buffers,
+};
+EXPORT_SYMBOL_GPL(mx1_mx2_soc_platform);
+
+static int __init mx1_mx2_soc_platform_init(void)
+{
+        return snd_soc_register_platform(&mx1_mx2_soc_platform);
+}
+module_init(mx1_mx2_soc_platform_init);
+
+static void __exit mx1_mx2_soc_platform_exit(void)
+{
+        snd_soc_unregister_platform(&mx1_mx2_soc_platform);
+}
+module_exit(mx1_mx2_soc_platform_exit);
+
+MODULE_AUTHOR("Javier Martin, javier.martin@vista-silicon.com");
+MODULE_DESCRIPTION("Freescale i.MX2x, i.MX1x PCM DMA module");
+MODULE_LICENSE("GPL");