idma.c

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/*
 * sound/soc/samsung/idma.c
 *
 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
 *      http://www.samsung.com
 *
 * I2S0's Internal DMA driver
 *
 * 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.
 */
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include "i2s.h"
#include "idma.h"
#include "dma.h"
#include "i2s-regs.h"

#define ST_RUNNING      (1<<0)
#define ST_OPENED       (1<<1)

static const struct snd_pcm_hardware idma_hardware = {
    .info = SNDRV_PCM_INFO_INTERLEAVED |
            SNDRV_PCM_INFO_BLOCK_TRANSFER |
            SNDRV_PCM_INFO_MMAP |
            SNDRV_PCM_INFO_MMAP_VALID |
            SNDRV_PCM_INFO_PAUSE |
            SNDRV_PCM_INFO_RESUME,
    .formats = SNDRV_PCM_FMTBIT_S16_LE |
            SNDRV_PCM_FMTBIT_U16_LE |
            SNDRV_PCM_FMTBIT_S24_LE |
            SNDRV_PCM_FMTBIT_U24_LE |
            SNDRV_PCM_FMTBIT_U8 |
            SNDRV_PCM_FMTBIT_S8,
    .channels_min = 2,
    .channels_max = 2,
    .buffer_bytes_max = MAX_IDMA_BUFFER,
    .period_bytes_min = 128,
    .period_bytes_max = MAX_IDMA_PERIOD,
    .periods_min = 1,
    .periods_max = 2,
};

struct idma_ctrl {
    spinlock_t  lock;
    int     state;
    dma_addr_t  start;
    dma_addr_t  pos;
    dma_addr_t  end;
    dma_addr_t  period;
    dma_addr_t  periodsz;
    void        *token;
    void        (*cb)(void *dt, int bytes_xfer);
};

static struct idma_info {
    spinlock_t  lock;
    void         __iomem  *regs;
    dma_addr_t  lp_tx_addr;
} idma;

static void idma_getpos(dma_addr_t *src)
{
    *src = idma.lp_tx_addr +
        (readl(idma.regs + I2STRNCNT) & 0xffffff) * 4;
}

static int idma_enqueue(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct idma_ctrl *prtd = substream->runtime->private_data;
    u32 val;

    spin_lock(&prtd->lock);
    prtd->token = (void *) substream;
    spin_unlock(&prtd->lock);

    /* Internal DMA Level0 Interrupt Address */
    val = idma.lp_tx_addr + prtd->periodsz;
    writel(val, idma.regs + I2SLVL0ADDR);

    /* Start address0 of I2S internal DMA operation. */
    val = idma.lp_tx_addr;
    writel(val, idma.regs + I2SSTR0);

    /*
     * Transfer block size for I2S internal DMA.
     * Should decide transfer size before start dma operation
     */
    val = readl(idma.regs + I2SSIZE);
    val &= ~(I2SSIZE_TRNMSK << I2SSIZE_SHIFT);
    val |= (((runtime->dma_bytes >> 2) &
            I2SSIZE_TRNMSK) << I2SSIZE_SHIFT);
    writel(val, idma.regs + I2SSIZE);

    val = readl(idma.regs + I2SAHB);
    val |= AHB_INTENLVL0;
    writel(val, idma.regs + I2SAHB);

    return 0;
}

static void idma_setcallbk(struct snd_pcm_substream *substream,
                void (*cb)(void *, int))
{
    struct idma_ctrl *prtd = substream->runtime->private_data;

    spin_lock(&prtd->lock);
    prtd->cb = cb;
    spin_unlock(&prtd->lock);
}

static void idma_control(int op)
{
    u32 val = readl(idma.regs + I2SAHB);

    spin_lock(&idma.lock);

    switch (op) {
    case LPAM_DMA_START:
        val |= (AHB_INTENLVL0 | AHB_DMAEN);
        break;
    case LPAM_DMA_STOP:
        val &= ~(AHB_INTENLVL0 | AHB_DMAEN);
        break;
    default:
        spin_unlock(&idma.lock);
        return;
    }

    writel(val, idma.regs + I2SAHB);
    spin_unlock(&idma.lock);
}

static void idma_done(void *id, int bytes_xfer)
{
    struct snd_pcm_substream *substream = id;
    struct idma_ctrl *prtd = substream->runtime->private_data;

    if (prtd && (prtd->state & ST_RUNNING))
        snd_pcm_period_elapsed(substream);
}

static int idma_hw_params(struct snd_pcm_substream *substream,
                struct snd_pcm_hw_params *params)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct idma_ctrl *prtd = substream->runtime->private_data;
    u32 mod = readl(idma.regs + I2SMOD);
    u32 ahb = readl(idma.regs + I2SAHB);

    ahb |= (AHB_DMARLD | AHB_INTMASK);
    mod |= MOD_TXS_IDMA;
    writel(ahb, idma.regs + I2SAHB);
    writel(mod, idma.regs + I2SMOD);

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

    prtd->start = prtd->pos = runtime->dma_addr;
    prtd->period = params_periods(params);
    prtd->periodsz = params_period_bytes(params);
    prtd->end = runtime->dma_addr + runtime->dma_bytes;

    idma_setcallbk(substream, idma_done);

    return 0;
}

static int idma_hw_free(struct snd_pcm_substream *substream)
{
    snd_pcm_set_runtime_buffer(substream, NULL);

    return 0;
}

static int idma_prepare(struct snd_pcm_substream *substream)
{
    struct idma_ctrl *prtd = substream->runtime->private_data;

    prtd->pos = prtd->start;

    /* flush the DMA channel */
    idma_control(LPAM_DMA_STOP);
    idma_enqueue(substream);

    return 0;
}

static int idma_trigger(struct snd_pcm_substream *substream, int cmd)
{
    struct idma_ctrl *prtd = substream->runtime->private_data;
    int ret = 0;

    spin_lock(&prtd->lock);

    switch (cmd) {
    case SNDRV_PCM_TRIGGER_RESUME:
    case SNDRV_PCM_TRIGGER_START:
    case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        prtd->state |= ST_RUNNING;
        idma_control(LPAM_DMA_START);
        break;

    case SNDRV_PCM_TRIGGER_SUSPEND:
    case SNDRV_PCM_TRIGGER_STOP:
    case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        prtd->state &= ~ST_RUNNING;
        idma_control(LPAM_DMA_STOP);
        break;

    default:
        ret = -EINVAL;
        break;
    }

    spin_unlock(&prtd->lock);

    return ret;
}

static snd_pcm_uframes_t
    idma_pointer(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct idma_ctrl *prtd = runtime->private_data;
    dma_addr_t src;
    unsigned long res;

    spin_lock(&prtd->lock);

    idma_getpos(&src);
    res = src - prtd->start;

    spin_unlock(&prtd->lock);

    return bytes_to_frames(substream->runtime, res);
}

static int idma_mmap(struct snd_pcm_substream *substream,
    struct vm_area_struct *vma)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    unsigned long size, offset;
    int ret;

    /* From snd_pcm_lib_mmap_iomem */
    vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
    vma->vm_flags |= VM_IO;
    size = vma->vm_end - vma->vm_start;
    offset = vma->vm_pgoff << PAGE_SHIFT;
    ret = io_remap_pfn_range(vma, vma->vm_start,
            (runtime->dma_addr + offset) >> PAGE_SHIFT,
            size, vma->vm_page_prot);

    return ret;
}

static irqreturn_t iis_irq(int irqno, void *dev_id)
{
    struct idma_ctrl *prtd = (struct idma_ctrl *)dev_id;
    u32 iiscon, iisahb, val, addr;

    iisahb  = readl(idma.regs + I2SAHB);
    iiscon  = readl(idma.regs + I2SCON);

    val = (iisahb & AHB_LVL0INT) ? AHB_CLRLVL0INT : 0;

    if (val) {
        iisahb |= val;
        writel(iisahb, idma.regs + I2SAHB);

        addr = readl(idma.regs + I2SLVL0ADDR) - idma.lp_tx_addr;
        addr += prtd->periodsz;
        addr %= (prtd->end - prtd->start);
        addr += idma.lp_tx_addr;

        writel(addr, idma.regs + I2SLVL0ADDR);

        if (prtd->cb)
            prtd->cb(prtd->token, prtd->period);
    }

    return IRQ_HANDLED;
}

static int idma_open(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct idma_ctrl *prtd;
    int ret;

    snd_soc_set_runtime_hwparams(substream, &idma_hardware);

    prtd = kzalloc(sizeof(struct idma_ctrl), GFP_KERNEL);
    if (prtd == NULL)
        return -ENOMEM;

    ret = request_irq(IRQ_I2S0, iis_irq, 0, "i2s", prtd);
    if (ret < 0) {
        pr_err("fail to claim i2s irq , ret = %d\n", ret);
        kfree(prtd);
        return ret;
    }

    spin_lock_init(&prtd->lock);

    runtime->private_data = prtd;

    return 0;
}

static int idma_close(struct snd_pcm_substream *substream)
{
    struct snd_pcm_runtime *runtime = substream->runtime;
    struct idma_ctrl *prtd = runtime->private_data;

    free_irq(IRQ_I2S0, prtd);

    if (!prtd)
        pr_err("idma_close called with prtd == NULL\n");

    kfree(prtd);

    return 0;
}

static struct snd_pcm_ops idma_ops = {
    .open       = idma_open,
    .close      = idma_close,
    .ioctl      = snd_pcm_lib_ioctl,
    .trigger    = idma_trigger,
    .pointer    = idma_pointer,
    .mmap       = idma_mmap,
    .hw_params  = idma_hw_params,
    .hw_free    = idma_hw_free,
    .prepare    = idma_prepare,
};

static void idma_free(struct snd_pcm *pcm)
{
    struct snd_pcm_substream *substream;
    struct snd_dma_buffer *buf;

    substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
    if (!substream)
        return;

    buf = &substream->dma_buffer;
    if (!buf->area)
        return;

    iounmap(buf->area);

    buf->area = NULL;
    buf->addr = 0;
}

static int preallocate_idma_buffer(struct snd_pcm *pcm, int stream)
{
    struct snd_pcm_substream *substream = pcm->streams[stream].substream;
    struct snd_dma_buffer *buf = &substream->dma_buffer;

    buf->dev.dev = pcm->card->dev;
    buf->private_data = NULL;

    /* Assign PCM buffer pointers */
    buf->dev.type = SNDRV_DMA_TYPE_CONTINUOUS;
    buf->addr = idma.lp_tx_addr;
    buf->bytes = idma_hardware.buffer_bytes_max;
    buf->area = (unsigned char *)ioremap(buf->addr, buf->bytes);

    return 0;
}

static u64 idma_mask = DMA_BIT_MASK(32);

static int idma_new(struct snd_soc_pcm_runtime *rtd)
{
    struct snd_card *card = rtd->card->snd_card;
    struct snd_pcm *pcm = rtd->pcm;
    int ret = 0;

    if (!card->dev->dma_mask)
        card->dev->dma_mask = &idma_mask;
    if (!card->dev->coherent_dma_mask)
        card->dev->coherent_dma_mask = DMA_BIT_MASK(32);

    if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream) {
        ret = preallocate_idma_buffer(pcm,
                SNDRV_PCM_STREAM_PLAYBACK);
    }

    return ret;
}

void idma_reg_addr_init(void __iomem *regs, dma_addr_t addr)
{
    spin_lock_init(&idma.lock);
    idma.regs = regs;
    idma.lp_tx_addr = addr;
}

static struct snd_soc_platform_driver asoc_idma_platform = {
    .ops = &idma_ops,
    .pcm_new = idma_new,
    .pcm_free = idma_free,
};

static int __devinit asoc_idma_platform_probe(struct platform_device *pdev)
{
    return snd_soc_register_platform(&pdev->dev, &asoc_idma_platform);
}

static int __devexit asoc_idma_platform_remove(struct platform_device *pdev)
{
    snd_soc_unregister_platform(&pdev->dev);
    return 0;
}

static struct platform_driver asoc_idma_driver = {
    .driver = {
        .name = "samsung-idma",
        .owner = THIS_MODULE,
    },

    .probe = asoc_idma_platform_probe,
    .remove = __devexit_p(asoc_idma_platform_remove),
};

module_platform_driver(asoc_idma_driver);

MODULE_AUTHOR("Jaswinder Singh, <[email protected]>");
MODULE_DESCRIPTION("Samsung ASoC IDMA Driver");
MODULE_LICENSE("GPL");