SD卡驱动之中断函数

来源：互联网发布：暴风影音软件编辑：程序博客网时间：2024/06/05 11:42

static irqreturn_t s3cmci_irq(int irq, void *dev_id)
{
struct s3cmci_host *host = dev_id;
struct mmc_command *cmd;

//SDI命令状态寄存器，数据状态寄存器，FIFO状态寄存器，数据持续计数器寄存器，中断屏蔽寄存器。
u32 mci_csta, mci_dsta, mci_fsta, mci_dcnt, mci_imsk;

u32 mci_cclear = 0, mci_dclear;
unsigned long iflags;

//获取数据状态寄存器和中断屏蔽寄存器的值

mci_dsta = readl(host->base + S3C2410_SDIDSTA);
mci_imsk = readl(host->base + host->sdiimsk);

if (mci_dsta & S3C2410_SDIDSTA_SDIOIRQDETECT) {//如果发生了中断继续下一步
if (mci_imsk & S3C2410_SDIIMSK_SDIOIRQ) {//IntDet 中断使能。

mci_dclear = S3C2410_SDIDSTA_SDIOIRQDETECT;//清除中断发现的值
writel(mci_dclear, host->base + S3C2410_SDIDSTA);

   mmc_signal_sdio_irq(host->mmc);//发现了SD后的相关程序
   return IRQ_HANDLED;
  }
}

spin_lock_irqsave(&host->complete_lock, iflags);//获取锁和中断状态

mci_csta = readl(host->base + S3C2410_SDICMDSTAT);//获取命令状态状态寄存器
mci_dcnt = readl(host->base + S3C2410_SDIDCNT);//获取数据持续计数寄存器
mci_fsta = readl(host->base + S3C2410_SDIFSTA);//获取FIFO状态寄存器
mci_dclear = 0;

if ((host->complete_what == COMPLETION_NONE) ||
     (host->complete_what == COMPLETION_FINALIZE)) {
  host->status = "nothing to complete";//如果host->complete_what的值等于COMPLETION_NONE，COMPLETION_FINALIZE，说明还没传输等，然后中断标志，退出。
  clear_imask(host);
  goto irq_out;
}

if (!host->mrq) {//当前请求为空退出
  host->status = "no active mrq";
  clear_imask(host);
  goto irq_out;
}

cmd = host->cmd_is_stop ? host->mrq->stop : host->mrq->cmd;

if (!cmd) {
  host->status = "no active cmd";
  clear_imask(host);
  goto irq_out;
}

if (!s3cmci_host_usedma(host)) {//假如设置使用PIO模式传输进入程序里面。
if ((host->pio_active == XFER_WRITE) &&
(mci_fsta & S3C2410_SDIFSTA_TFDET)) {

   disable_imask(host, S3C2410_SDIIMSK_TXFIFOHALF);
   tasklet_schedule(&host->pio_tasklet);
   host->status = "pio tx";
  }

if ((host->pio_active == XFER_READ) &&
(mci_fsta & S3C2410_SDIFSTA_RFDET)) {

   disable_imask(host,
          S3C2410_SDIIMSK_RXFIFOHALF |
          S3C2410_SDIIMSK_RXFIFOLAST);

   tasklet_schedule(&host->pio_tasklet);
   host->status = "pio rx";
  }
}

if (mci_csta & S3C2410_SDICMDSTAT_CMDTIMEOUT) {//命令超时
  dbg(host, dbg_err, "CMDSTAT: error CMDTIMEOUT\n");
  cmd->error = -ETIMEDOUT;
  host->status = "error: command timeout";
  goto fail_transfer;
}

if (mci_csta & S3C2410_SDICMDSTAT_CMDSENT) {//命令发送了
  if (host->complete_what == COMPLETION_CMDSENT) {
   host->status = "ok: command sent";
   goto close_transfer;
  }

mci_cclear |= S3C2410_SDICMDSTAT_CMDSENT;
}

if (mci_csta & S3C2410_SDICMDSTAT_CRCFAIL) {//响应CRC失败
  if (cmd->flags & MMC_RSP_CRC) {
   if (host->mrq->cmd->flags & MMC_RSP_136) {
    dbg(host, dbg_irq,
        "fixup: ignore CRC fail with long rsp\n");
   } else {

   }
  }

mci_cclear |= S3C2410_SDICMDSTAT_CRCFAIL;
}

if (mci_csta & S3C2410_SDICMDSTAT_RSPFIN) {//响应接受结束
  if (host->complete_what == COMPLETION_RSPFIN) {
   host->status = "ok: command response received";
   goto close_transfer;
  }

if (host->complete_what == COMPLETION_XFERFINISH_RSPFIN)
host->complete_what = COMPLETION_XFERFINISH;

mci_cclear |= S3C2410_SDICMDSTAT_RSPFIN;
}

if (!cmd->data)
goto clear_status_bits;

下面的是FIFO出错处理程序

if (host->is2440) {//主机是2440下一步
  if (mci_fsta & S3C2440_SDIFSTA_FIFOFAIL) {//FIFO 失败错误,当FIFO 发生溢出/欠载（underrun）数据保存时FIFO失败错误。
   dbg(host, dbg_err, "FIFO failure\n");
   host->mrq->data->error = -EILSEQ;
   host->status = "error: 2440 fifo failure";
   goto fail_transfer;
  }
} else {
  if (mci_dsta & S3C2410_SDIDSTA_FIFOFAIL) {
   dbg(host, dbg_err, "FIFO failure\n");
   cmd->data->error = -EILSEQ;
   host->status = "error: fifo failure";
   goto fail_transfer;
  }
}

if (mci_dsta & S3C2410_SDIDSTA_RXCRCFAIL) {//数据接收CRC校验失败

  dbg(host, dbg_err, "bad data crc (outgoing)\n");
  cmd->data->error = -EILSEQ;
  host->status = "error: bad data crc (outgoing)";
  goto fail_transfer;
}

if (mci_dsta & S3C2410_SDIDSTA_CRCFAIL) { //CRC状态失败，当数据块发送时CRC状态错误(CRC 校验失败)。

  dbg(host, dbg_err, "bad data crc (incoming)\n");
  cmd->data->error = -EILSEQ;
  host->status = "error: bad data crc (incoming)";
  goto fail_transfer;
}

if (mci_dsta & S3C2410_SDIDSTA_DATATIMEOUT) { //数据接收超时

  dbg(host, dbg_err, "data timeout\n");
  cmd->data->error = -ETIMEDOUT;
  host->status = "error: data timeout";
  goto fail_transfer;
}

if (mci_dsta & S3C2410_SDIDSTA_XFERFINISH) {//数据传输结束
  if (host->complete_what == COMPLETION_XFERFINISH) {//
   host->status = "ok: data transfer completed";
   goto close_transfer;
  }

if (host->complete_what == COMPLETION_XFERFINISH_RSPFIN)
host->complete_what = COMPLETION_RSPFIN;

mci_dclear |= S3C2410_SDIDSTA_XFERFINISH;
}

clear_status_bits:
writel(mci_cclear, host->base + S3C2410_SDICMDSTAT);
writel(mci_dclear, host->base + S3C2410_SDIDSTA);

goto irq_out;

fail_transfer:
host->pio_active = XFER_NONE;

close_transfer:
host->complete_what = COMPLETION_FINALIZE;

clear_imask(host);
tasklet_schedule(&host->pio_tasklet);

goto irq_out;

irq_out:
dbg(host, dbg_irq,
"csta:0xx dsta:0xx fsta:0xx dcnt:0xx status:%s.\n",
mci_csta, mci_dsta, mci_fsta, mci_dcnt, host->status);

spin_unlock_irqrestore(&host->complete_lock, iflags);
return IRQ_HANDLED;

}