pxa2xx-pcm-lib.c

Go to the documentation of this file.

/*
 * 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/slab.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/pxa2xx-lib.h>

#include <mach/dma.h>

#include "pxa2xx-pcm.h"

static const struct snd_pcm_hardware pxa2xx_pcm_hardware = {
    .info           = SNDRV_PCM_INFO_MMAP |
                  SNDRV_PCM_INFO_MMAP_VALID |
                  SNDRV_PCM_INFO_INTERLEAVED |
                  SNDRV_PCM_INFO_PAUSE |
                  SNDRV_PCM_INFO_RESUME,
    .formats        = SNDRV_PCM_FMTBIT_S16_LE |
                    SNDRV_PCM_FMTBIT_S24_LE |
                    SNDRV_PCM_FMTBIT_S32_LE,
    .period_bytes_min   = 32,
    .period_bytes_max   = 8192 - 32,
    .periods_min        = 1,
    .periods_max        = PAGE_SIZE/sizeof(pxa_dma_desc),
    .buffer_bytes_max   = 128 * 1024,
    .fifo_size      = 32,
};

int __pxa2xx_pcm_hw_params(struct snd_pcm_substream *substream,
                struct snd_pcm_hw_params *params)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct pxa2xx_runtime_data *rtd = runtime->private_data;
    size_t totsize = params_buffer_bytes(params);
    size_t period = params_period_bytes(params);
    pxa_dma_desc *dma_desc;
    dma_addr_t dma_buff_phys, next_desc_phys;

    snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);
    runtime->dma_bytes = totsize;

    dma_desc = rtd->dma_desc_array;
    next_desc_phys = rtd->dma_desc_array_phys;
    dma_buff_phys = runtime->dma_addr;
    do {
        next_desc_phys += sizeof(pxa_dma_desc);
        dma_desc->ddadr = next_desc_phys;
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
            dma_desc->dsadr = dma_buff_phys;
            dma_desc->dtadr = rtd->params->dev_addr;
        } else {
            dma_desc->dsadr = rtd->params->dev_addr;
            dma_desc->dtadr = dma_buff_phys;
        }
        if (period > totsize)
            period = totsize;
        dma_desc->dcmd = rtd->params->dcmd | period | DCMD_ENDIRQEN;
        dma_desc++;
        dma_buff_phys += period;
    } while (totsize -= period);
    dma_desc[-1].ddadr = rtd->dma_desc_array_phys;

    return 0;
}
EXPORT_SYMBOL(__pxa2xx_pcm_hw_params);

int __pxa2xx_pcm_hw_free(struct snd_pcm_substream *substream)
{
    struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;

    if (rtd && rtd->params && rtd->params->drcmr)
        *rtd->params->drcmr = 0;

    snd_pcm_set_runtime_buffer(substream, NULL);
    return 0;
}
EXPORT_SYMBOL(__pxa2xx_pcm_hw_free);

int pxa2xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;
    int ret = 0;

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_START:
        DDADR(prtd->dma_ch) = prtd->dma_desc_array_phys;
        DCSR(prtd->dma_ch) = DCSR_RUN;
        break;

    case SNDRV_PCM_TRIGGER_STOP:
    case SNDRV_PCM_TRIGGER_SUSPEND:
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        DCSR(prtd->dma_ch) &= ~DCSR_RUN;
        break;

    case SNDRV_PCM_TRIGGER_RESUME:
        DCSR(prtd->dma_ch) |= DCSR_RUN;
        break;
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        DDADR(prtd->dma_ch) = prtd->dma_desc_array_phys;
        DCSR(prtd->dma_ch) |= DCSR_RUN;
        break;

    default:
        ret = -EINVAL;
    }

    return ret;
}
EXPORT_SYMBOL(pxa2xx_pcm_trigger);

snd_pcm_uframes_t
pxa2xx_pcm_pointer(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct pxa2xx_runtime_data *prtd = runtime->private_data;

    dma_addr_t ptr = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) ?
             DSADR(prtd->dma_ch) : DTADR(prtd->dma_ch);
    snd_pcm_uframes_t x = bytes_to_frames(runtime, ptr - runtime->dma_addr);

    if (x == runtime->buffer_size)
        x = 0;
    return x;
}
EXPORT_SYMBOL(pxa2xx_pcm_pointer);

int __pxa2xx_pcm_prepare(struct snd_pcm_substream *substream)
{
    struct pxa2xx_runtime_data *prtd = substream->runtime->private_data;

    if (!prtd || !prtd->params)
        return 0;

    if (prtd->dma_ch == -1)
        return -EINVAL;

    DCSR(prtd->dma_ch) &= ~DCSR_RUN;
    DCSR(prtd->dma_ch) = 0;
    DCMD(prtd->dma_ch) = 0;
    *prtd->params->drcmr = prtd->dma_ch | DRCMR_MAPVLD;

    return 0;
}
EXPORT_SYMBOL(__pxa2xx_pcm_prepare);

void pxa2xx_pcm_dma_irq(int dma_ch, void *dev_id)
{
    struct snd_pcm_substream *substream = dev_id;
    struct pxa2xx_runtime_data *rtd = substream->runtime->private_data;
    int dcsr;

    dcsr = DCSR(dma_ch);
    DCSR(dma_ch) = dcsr & ~DCSR_STOPIRQEN;

    if (dcsr & DCSR_ENDINTR) {
        snd_pcm_period_elapsed(substream);
    } else {
        printk(KERN_ERR "%s: DMA error on channel %d (DCSR=%#x)\n",
            rtd->params->name, dma_ch, dcsr);
        snd_pcm_stop(substream, SNDRV_PCM_STATE_XRUN);
    }
}
EXPORT_SYMBOL(pxa2xx_pcm_dma_irq);

int __pxa2xx_pcm_open(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct pxa2xx_runtime_data *rtd;
    int ret;

    runtime->hw = pxa2xx_pcm_hardware;

    /*
     * For mysterious reasons (and despite what the manual says)
     * playback samples are lost if the DMA count is not a multiple
     * of the DMA burst size.  Let's add a rule to enforce that.
     */
    ret = snd_pcm_hw_constraint_step(runtime, 0,
        SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 32);
    if (ret)
        goto out;

    ret = snd_pcm_hw_constraint_step(runtime, 0,
        SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 32);
    if (ret)
        goto out;

    ret = snd_pcm_hw_constraint_integer(runtime,
                        SNDRV_PCM_HW_PARAM_PERIODS);
    if (ret < 0)
        goto out;

    ret = -ENOMEM;
    rtd = kzalloc(sizeof(*rtd), GFP_KERNEL);
    if (!rtd)
        goto out;
    rtd->dma_desc_array =
        dma_alloc_writecombine(substream->pcm->card->dev, PAGE_SIZE,
                       &rtd->dma_desc_array_phys, GFP_KERNEL);
    if (!rtd->dma_desc_array)
        goto err1;

    rtd->dma_ch = -1;
    runtime->private_data = rtd;
    return 0;

 err1:
    kfree(rtd);
 out:
    return ret;
}
EXPORT_SYMBOL(__pxa2xx_pcm_open);

int __pxa2xx_pcm_close(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct pxa2xx_runtime_data *rtd = runtime->private_data;

    dma_free_writecombine(substream->pcm->card->dev, PAGE_SIZE,
                  rtd->dma_desc_array, rtd->dma_desc_array_phys);
    kfree(rtd);
    return 0;
}
EXPORT_SYMBOL(__pxa2xx_pcm_close);

int pxa2xx_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);
}
EXPORT_SYMBOL(pxa2xx_pcm_mmap);

int pxa2xx_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 = pxa2xx_pcm_hardware.buffer_bytes_max;
    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;
}
EXPORT_SYMBOL(pxa2xx_pcm_preallocate_dma_buffer);

void pxa2xx_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;
    }
}
EXPORT_SYMBOL(pxa2xx_pcm_free_dma_buffers);

MODULE_AUTHOR("Nicolas Pitre");
MODULE_DESCRIPTION("Intel PXA2xx sound library");
MODULE_LICENSE("GPL");