解决在arm2440休眠唤醒后出现大量类似** yaffs chunk 123 was not erased的问题

在把休眠的2440通过外部中断唤醒后，运行其他命令会出现大量类似提示：

**>> yaffs chunk 12352 was not erased
**>> yaffs chunk 12353 was not erased
**>> yaffs chunk 12354 was not erased
**>> yaffs chunk 12355 was not erased
**>> yaffs chunk 12356 was not erased
**>> yaffs chunk 12357 was not erased
**>> yaffs chunk 12358 was not erased
**>> yaffs chunk 12359 was not erased
**>> yaffs chunk 12360 was not erased
**>> yaffs chunk 12361 was not erased
**>> yaffs chunk 12362 was not erased
**>> yaffs chunk 12363 was not erased
**>> yaffs chunk 12364 was not erased

这是由于nandflash驱动程序没有suspend、resume函数，造成休眠、唤醒过程中没有保存NAND FLASH控制器的寄存器状态。

应该在drivers/mtd/nand/s3c2410.c中添加suspend、resume函数 如下：

*add by cefanty 2006-10-26 to support PM*/
*add by cefanty 2006-10-26 to support PM*/
#ifdef CONFIG_PM

static int s3c24xx_nand_suspend(struct platform_device *pdev, pm_message_t pmsg)
{
struct s3c2410_nand_info *info = platform_get_drvdata(pdev);

if (info) {
if (!allow_clk_stop(info))
clk_disable(info->clk);
}
return 0;
}

static int s3c24xx_nand_resume(struct platform_device *pdev)
{
struct s3c2410_nand_info *info = platform_get_drvdata(pdev);

if (info) {
clk_enable(info->clk);
s3c2410_nand_inithw(info, pdev);

if (allow_clk_stop(info))
clk_disable(info->clk);
}

return 0;
}

#else
#define s3c24xx_nand_suspend NULL
#define s3c24xx_nand_resume NULL
#endif

static struct platform_driver s3c2410_nand_driver = {
.probe = s3c2410_nand_probe,
.remove = s3c2410_nand_remove,
.suspend = s3c24xx_nand_suspend,
.resume = s3c24xx_nand_resume,
.driver = {
.name = "s3c2410-nand",
.owner = THIS_MODULE,
},
};

在resume函数中会调用s3c2410_nand_inithw函数重新初始化nandflash寄存器如下：

static int s3c2410_nand_inithw(struct s3c2410_nand_info *info,
          struct platform_device *pdev)
{
 struct s3c2410_platform_nand *plat = to_nand_plat(pdev);
 unsigned long clkrate = clk_get_rate(info->clk);
 int tacls_max = (info->cpu_type == TYPE_S3C2412) ? 8 : 4;
 int tacls, twrph0, twrph1;
 unsigned long cfg = 0;

 /* calculate the timing information for the controller */

 clkrate /= 1000; /* turn clock into kHz for ease of use */

 if (plat != NULL) {
  tacls = s3c_nand_calc_rate(plat->tacls, clkrate, tacls_max);
  twrph0 = s3c_nand_calc_rate(plat->twrph0, clkrate, 8);
  twrph1 = s3c_nand_calc_rate(plat->twrph1, clkrate, 8);
 } else {
  /* default timings */
  tacls = tacls_max;
  twrph0 = 8;
  twrph1 = 8;
 }

 if (tacls < 0 || twrph0 < 0 || twrph1 < 0) {
  dev_err(info->device, "cannot get suitable timings/n");
  return -EINVAL;
 }

 dev_info(info->device, "Tacls=%d, %dns Twrph0=%d %dns, Twrph1=%d %dns/n",
        tacls, to_ns(tacls, clkrate), twrph0, to_ns(twrph0, clkrate), twrph1, to_ns(twrph1, clkrate));

  switch (info->cpu_type) {
  case TYPE_S3C2410:
  cfg = S3C2410_NFCONF_EN;
  cfg |= S3C2410_NFCONF_TACLS(tacls - 1);
  cfg |= S3C2410_NFCONF_TWRPH0(twrph0 - 1);
  cfg |= S3C2410_NFCONF_TWRPH1(twrph1 - 1);
  break;

  case TYPE_S3C2440:
  case TYPE_S3C2412:
  cfg = S3C2440_NFCONF_TACLS(tacls - 1);
  cfg |= S3C2440_NFCONF_TWRPH0(twrph0 - 1);
  cfg |= S3C2440_NFCONF_TWRPH1(twrph1 - 1);

  /* enable the controller and de-assert nFCE */

  writel(S3C2440_NFCONT_ENABLE, info->regs + S3C2440_NFCONT);
 }

 dev_dbg(info->device, "NF_CONF is 0x%lx/n", cfg);

 writel(cfg, info->regs + S3C2410_NFCONF);
 return 0;
}

其中 writel(S3C2440_NFCONT_ENABLE, info->regs + S3C2440_NFCONT);一句很重要

我一开始就因为没发现少了这句代码才一直做不对。

添加上这句代码后 就可以正常休眠/唤醒了。