［转］基于uda34x的ALSA声卡驱动之s3c24xx-i2s.c

最新推荐文章于 2022-07-11 17:18:31 发布

cocosasa

最新推荐文章于 2022-07-11 17:18:31 发布

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文章标签： c struct iis module div stream

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/jiffies.h>
#include <linux/io.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/initval.h>
#include <sound/soc.h>

#include <mach/hardware.h>
#include <mach/regs-gpio.h>
#include <mach/regs-clock.h>
#include <mach/audio.h>
#include <asm/dma.h>
#include <mach/dma.h>

#include <asm/plat-s3c24xx/regs-iis.h>

#include "s3c24xx-pcm.h"
#include "s3c24xx-i2s.h"

#define S3C24XX_I2S_DEBUG 0
#if S3C24XX_I2S_DEBUG
#define DBG(x...) printk(KERN_DEBUG "s3c24xx-i2s: " x)
#else
#define DBG(x...)
#endif

static struct s3c2410_dma_client s3c24xx_dma_client_out = {
.name = "I2S PCM Stereo out"
};

static struct s3c2410_dma_client s3c24xx_dma_client_in = {
.name = "I2S PCM Stereo in"
};
/*
结构体s3c24xx_i2s_pcm_stereo_out在下面函数s3c24xx_i2s_hw_params中被挂到
rtd->dai->cpu_dai->dma_data上。在文件s3c24xx-pcm.c中有函数s3c24xx_pcm_hw_params，
在该函数中该结构体将再被挂到substream->runtime->private_data上。并在申请DMA通道时被使用
*/
static struct s3c24xx_pcm_dma_params s3c24xx_i2s_pcm_stereo_out = {
.client = &s3c24xx_dma_client_out,
.channel = DMACH_I2S_OUT,
.dma_addr = S3C2410_PA_IIS + S3C2410_IISFIFO,
.dma_size = 2,
};

static struct s3c24xx_pcm_dma_params s3c24xx_i2s_pcm_stereo_in = {
.client  = &s3c24xx_dma_client_in,
.channel = DMACH_I2S_IN,
.dma_addr = S3C2410_PA_IIS + S3C2410_IISFIFO,
.dma_size = 2,
};
//存放iis基地址和iis个寄存器的值
struct s3c24xx_i2s_info {
void __iomem *regs;
struct clk *iis_clk;
u32  iiscon;
u32  iismod;
u32  iisfcon;
u32  iispsr;
};
static struct s3c24xx_i2s_info s3c24xx_i2s;
//配置iis各寄存器使其处于发送状态，或停止发送
static void s3c24xx_snd_txctrl(int on)
{
u32 iisfcon;
u32 iiscon;
u32 iismod;

DBG("Entered %s/n", __func__);

iisfcon = readl(s3c24xx_i2s.regs + S3C2410_IISFCON);
iiscon = readl(s3c24xx_i2s.regs + S3C2410_IISCON);
iismod = readl(s3c24xx_i2s.regs + S3C2410_IISMOD);

DBG("r: IISCON: %lx IISMOD: %lx IISFCON: %lx/n", iiscon, iismod, iisfcon);

if (on) {
  iisfcon |= S3C2410_IISFCON_TXDMA | S3C2410_IISFCON_TXENABLE;
  iiscon |= S3C2410_IISCON_TXDMAEN | S3C2410_IISCON_IISEN;
  iiscon &= ~S3C2410_IISCON_TXIDLE;
  iismod |= S3C2410_IISMOD_TXMODE;

  writel(iismod, s3c24xx_i2s.regs + S3C2410_IISMOD);
  writel(iisfcon, s3c24xx_i2s.regs + S3C2410_IISFCON);
  writel(iiscon, s3c24xx_i2s.regs + S3C2410_IISCON);
} else {
  /* note, we have to disable the FIFOs otherwise bad things
   * seem to happen when the DMA stops. According to the
   * Samsung supplied kernel, this should allow the DMA
   * engine and FIFOs to reset. If this isn't allowed, the
   * DMA engine will simply freeze randomly.
   */

  iisfcon &= ~S3C2410_IISFCON_TXENABLE;
  iisfcon &= ~S3C2410_IISFCON_TXDMA;
  iiscon |= S3C2410_IISCON_TXIDLE;
  iiscon &= ~S3C2410_IISCON_TXDMAEN;
  iismod &= ~S3C2410_IISMOD_TXMODE;

  writel(iiscon, s3c24xx_i2s.regs + S3C2410_IISCON);
  writel(iisfcon, s3c24xx_i2s.regs + S3C2410_IISFCON);
  writel(iismod, s3c24xx_i2s.regs + S3C2410_IISMOD);
}

DBG("w: IISCON: %lx IISMOD: %lx IISFCON: %lx/n", iiscon, iismod, iisfcon);
}
//配置iis各寄存器使其处于接收状态或停止发送
static void s3c24xx_snd_rxctrl(int on)
{
u32 iisfcon;
u32 iiscon;
u32 iismod;

DBG("Entered %s/n", __func__);

iisfcon = readl(s3c24xx_i2s.regs + S3C2410_IISFCON);
iiscon = readl(s3c24xx_i2s.regs + S3C2410_IISCON);
iismod = readl(s3c24xx_i2s.regs + S3C2410_IISMOD);

DBG("r: IISCON: %lx IISMOD: %lx IISFCON: %lx/n", iiscon, iismod, iisfcon);

if (on) {
  iisfcon |= S3C2410_IISFCON_RXDMA | S3C2410_IISFCON_RXENABLE;
  iiscon |= S3C2410_IISCON_RXDMAEN | S3C2410_IISCON_IISEN;
  iiscon &= ~S3C2410_IISCON_RXIDLE;
  iismod |= S3C2410_IISMOD_RXMODE;

  iisfcon &= ~S3C2410_IISFCON_RXENABLE;
  iisfcon &= ~S3C2410_IISFCON_RXDMA;
  iiscon |= S3C2410_IISCON_RXIDLE;
  iiscon &= ~S3C2410_IISCON_RXDMAEN;
  iismod &= ~S3C2410_IISMOD_RXMODE;

  writel(iisfcon, s3c24xx_i2s.regs + S3C2410_IISFCON);
  writel(iiscon, s3c24xx_i2s.regs + S3C2410_IISCON);
  writel(iismod, s3c24xx_i2s.regs + S3C2410_IISMOD);
}

DBG("w: IISCON: %lx IISMOD: %lx IISFCON: %lx/n", iiscon, iismod, iisfcon);
}

/*
* Wait for the LR signal to allow synchronisation to the L/R clock
* from the codec. May only be needed for slave mode.
*/
static int s3c24xx_snd_lrsync(void)
{
u32 iiscon;
int timeout = 50; /* 5ms */

DBG("Entered %s/n", __func__);

while (1) {
  iiscon = readl(s3c24xx_i2s.regs + S3C2410_IISCON);
  if (iiscon & S3C2410_IISCON_LRINDEX)
   break;

  if (!timeout--)
   return -ETIMEDOUT;
  udelay(100);
}

return 0;
}

/*
* Check whether CPU is the master or slave
*///读取iis的主从模式
static inline int s3c24xx_snd_is_clkmaster(void)
{
DBG("Entered %s/n", __func__);

return (readl(s3c24xx_i2s.regs + S3C2410_IISMOD) & S3C2410_IISMOD_SLAVE) ? 0:1;
}

/*
* Set S3C24xx I2S DAI format
*///设置iis的工作模式
static int s3c24xx_i2s_set_fmt(struct snd_soc_dai *cpu_dai,
unsigned int fmt)
{
u32 iismod;

DBG("Entered %s/n", __func__);

iismod = readl(s3c24xx_i2s.regs + S3C2410_IISMOD);
DBG("hw_params r: IISMOD: %lx /n", iismod);

switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
case SND_SOC_DAIFMT_CBM_CFM:
  iismod |= S3C2410_IISMOD_SLAVE;
  break;
case SND_SOC_DAIFMT_CBS_CFS:
  iismod &= ~S3C2410_IISMOD_SLAVE;
  break;
default:
  return -EINVAL;
}

switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
case SND_SOC_DAIFMT_LEFT_J:
  iismod |= S3C2410_IISMOD_MSB;
  break;
case SND_SOC_DAIFMT_I2S:
  iismod &= ~S3C2410_IISMOD_MSB;
  break;
default:
  return -EINVAL;
}

writel(iismod, s3c24xx_i2s.regs + S3C2410_IISMOD);
DBG("hw_params w: IISMOD: %lx /n", iismod);
return 0;
}
//设置iis串行传输数据大小，以及DMA传输数据大小单位
static int s3c24xx_i2s_hw_params(struct snd_pcm_substream *substream,
struct snd_pcm_hw_params *params,
struct snd_soc_dai *dai)
{
struct snd_soc_pcm_runtime *rtd = substream->private_data;
u32 iismod;

DBG("Entered %s/n", __func__);

if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
rtd->dai->cpu_dai->dma_data = &s3c24xx_i2s_pcm_stereo_out;
else
rtd->dai->cpu_dai->dma_data = &s3c24xx_i2s_pcm_stereo_in;

/* Working copies of register */
iismod = readl(s3c24xx_i2s.regs + S3C2410_IISMOD);
DBG("hw_params r: IISMOD: %lx/n", iismod);

switch (params_format(params)) {
case SNDRV_PCM_FORMAT_S8:
  iismod &= ~S3C2410_IISMOD_16BIT;
  ((struct s3c24xx_pcm_dma_params *)
    rtd->dai->cpu_dai->dma_data)->dma_size = 1;
  break;
case SNDRV_PCM_FORMAT_S16_LE:
  iismod |= S3C2410_IISMOD_16BIT;
  ((struct s3c24xx_pcm_dma_params *)
    rtd->dai->cpu_dai->dma_data)->dma_size = 2;
  break;
default:
  return -EINVAL;
}

writel(iismod, s3c24xx_i2s.regs + S3C2410_IISMOD);
DBG("hw_params w: IISMOD: %lx/n", iismod);
return 0;
}
//控制录音或播放的开始和停止
static int s3c24xx_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
struct snd_soc_dai *dai)
{
int ret = 0;

DBG("Entered %s/n", __func__);

switch (cmd) {
case SNDRV_PCM_TRIGGER_START:
case SNDRV_PCM_TRIGGER_RESUME:
case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
  if (!s3c24xx_snd_is_clkmaster()) {
   ret = s3c24xx_snd_lrsync();
   if (ret)
    goto exit_err;
  }

  if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
   s3c24xx_snd_rxctrl(1);//录音
  else
   s3c24xx_snd_txctrl(1);//播放
  break;
case SNDRV_PCM_TRIGGER_STOP:
case SNDRV_PCM_TRIGGER_SUSPEND:
case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
  if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
   s3c24xx_snd_rxctrl(0);
  else
   s3c24xx_snd_txctrl(0);
  break;
default:
  ret = -EINVAL;
  break;
}

exit_err:
return ret;
}

/*
* Set S3C24xx Clock source
*///选择iis主设备的时钟PCLK或MPLLin
static int s3c24xx_i2s_set_sysclk(struct snd_soc_dai *cpu_dai,
int clk_id, unsigned int freq, int dir)
{
u32 iismod = readl(s3c24xx_i2s.regs + S3C2410_IISMOD);

DBG("Entered %s/n", __func__);

iismod &= ~S3C2440_IISMOD_MPLL;

switch (clk_id) {
case S3C24XX_CLKSRC_PCLK:
  break;
case S3C24XX_CLKSRC_MPLL:
  iismod |= S3C2440_IISMOD_MPLL;
  break;
default:
  return -EINVAL;
}

writel(iismod, s3c24xx_i2s.regs + S3C2410_IISMOD);
return 0;
}

/*
* Set S3C24xx Clock dividers
*/
static int s3c24xx_i2s_set_clkdiv(struct snd_soc_dai *cpu_dai,
int div_id, int div)
{
u32 reg;

DBG("Entered %s/n", __func__);

switch (div_id) {
case S3C24XX_DIV_BCLK://串行时钟频率的选择16fs，32fs，48fs
  reg = readl(s3c24xx_i2s.regs + S3C2410_IISMOD) & ~S3C2410_IISMOD_FS_MASK;
  writel(reg | div, s3c24xx_i2s.regs + S3C2410_IISMOD);
  break;
case S3C24XX_DIV_MCLK://主时钟频率选择256fs，348fs（348倍采样频率）
  reg = readl(s3c24xx_i2s.regs + S3C2410_IISMOD) & ~(S3C2410_IISMOD_384FS);
  writel(reg | div, s3c24xx_i2s.regs + S3C2410_IISMOD);
  break;
case S3C24XX_DIV_PRESCALER://分频值的设定
  writel(div, s3c24xx_i2s.regs + S3C2410_IISPSR);
  reg = readl(s3c24xx_i2s.regs + S3C2410_IISCON);
  writel(reg | S3C2410_IISCON_PSCEN, s3c24xx_i2s.regs + S3C2410_IISCON);
  break;
default:
  return -EINVAL;
}

return 0;
}

/*
* To avoid duplicating clock code, allow machine driver to
* get the clockrate from here.
*/
u32 s3c24xx_i2s_get_clockrate(void)
{
return clk_get_rate(s3c24xx_i2s.iis_clk);
}
EXPORT_SYMBOL_GPL(s3c24xx_i2s_get_clockrate);

static int s3c24xx_i2s_probe(struct platform_device *pdev,
        struct snd_soc_dai *dai)
{
DBG("Entered %s/n", __func__);
//将以S3C2410_PA_IIS为起始0x100的一段物理地址映射为一段虚拟地址
s3c24xx_i2s.regs = ioremap(S3C2410_PA_IIS, 0x100);
if (s3c24xx_i2s.regs == NULL)
  return -ENXIO;
//此处的时钟为iis模块时序电路工作所需时钟，前面所设时钟为串行数据传输频率
s3c24xx_i2s.iis_clk = clk_get(&pdev->dev, "iis");
if (s3c24xx_i2s.iis_clk == NULL) {
  DBG("failed to get iis_clock/n");
  iounmap(s3c24xx_i2s.regs);
  return -ENODEV;
}
clk_enable(s3c24xx_i2s.iis_clk);
//配置iis个管脚的工作模式
/* Configure the I2S pins in correct mode */
s3c2410_gpio_cfgpin(S3C2410_GPE0, S3C2410_GPE0_I2SLRCK);
s3c2410_gpio_cfgpin(S3C2410_GPE1, S3C2410_GPE1_I2SSCLK);
s3c2410_gpio_cfgpin(S3C2410_GPE2, S3C2410_GPE2_CDCLK);
s3c2410_gpio_cfgpin(S3C2410_GPE3, S3C2410_GPE3_I2SSDI);
s3c2410_gpio_cfgpin(S3C2410_GPE4, S3C2410_GPE4_I2SSDO);

writel(S3C2410_IISCON_IISEN, s3c24xx_i2s.regs + S3C2410_IISCON);

s3c24xx_snd_txctrl(0);
s3c24xx_snd_rxctrl(0);

return 0;
}

#ifdef CONFIG_PM
static int s3c24xx_i2s_suspend(struct snd_soc_dai *cpu_dai)
{
DBG("Entered %s/n", __func__);
//将各配置存入结构体中
s3c24xx_i2s.iiscon = readl(s3c24xx_i2s.regs + S3C2410_IISCON);
s3c24xx_i2s.iismod = readl(s3c24xx_i2s.regs + S3C2410_IISMOD);
s3c24xx_i2s.iisfcon = readl(s3c24xx_i2s.regs + S3C2410_IISFCON);
s3c24xx_i2s.iispsr = readl(s3c24xx_i2s.regs + S3C2410_IISPSR);

clk_disable(s3c24xx_i2s.iis_clk);//禁止时钟，即暂停

return 0;
}

static int s3c24xx_i2s_resume(struct snd_soc_dai *cpu_dai)
{
DBG("Entered %s/n", __func__);
clk_enable(s3c24xx_i2s.iis_clk);

writel(s3c24xx_i2s.iiscon, s3c24xx_i2s.regs + S3C2410_IISCON);
writel(s3c24xx_i2s.iismod, s3c24xx_i2s.regs + S3C2410_IISMOD);
writel(s3c24xx_i2s.iisfcon, s3c24xx_i2s.regs + S3C2410_IISFCON);
writel(s3c24xx_i2s.iispsr, s3c24xx_i2s.regs + S3C2410_IISPSR);

return 0;
}
#else
#define s3c24xx_i2s_suspend NULL
#define s3c24xx_i2s_resume NULL
#endif

struct snd_soc_dai s3c24xx_i2s_dai = {
.name = "s3c24xx-i2s",
.id = 0,
.probe = s3c24xx_i2s_probe,
.suspend = s3c24xx_i2s_suspend,
.resume = s3c24xx_i2s_resume,
.playback = {//播放
  .channels_min = 2,
  .channels_max = 2,
  .rates = S3C24XX_I2S_RATES,
  .formats = SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_LE,},
.capture = {//录音
  .channels_min = 2,
  .channels_max = 2,
  .rates = S3C24XX_I2S_RATES,
  .formats = SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_LE,},
.ops = {//iis操作函数
  .trigger = s3c24xx_i2s_trigger,
  .hw_params = s3c24xx_i2s_hw_params,
  .set_fmt = s3c24xx_i2s_set_fmt,
  .set_clkdiv = s3c24xx_i2s_set_clkdiv,
  .set_sysclk = s3c24xx_i2s_set_sysclk,
},
};
EXPORT_SYMBOL_GPL(s3c24xx_i2s_dai);

static int __init s3c24xx_i2s_init(void)
{//将s3c24xx_i2s_dai 挂到链表dai_list上，调用函数snd_soc_instantiate_card，
//如果本声卡没有初始化，则从各链表上取下相应结构体，并调用各结构体中的初始化函数，
return snd_soc_register_dai(&s3c24xx_i2s_dai);
}
module_init(s3c24xx_i2s_init);

static void __exit s3c24xx_i2s_exit(void)
{
snd_soc_unregister_dai(&s3c24xx_i2s_dai);
}
module_exit(s3c24xx_i2s_exit);

/* Module information */
MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk >");
MODULE_DESCRIPTION("s3c24xx I2S SoC Interface");
MODULE_LICENSE("GPL");