关于3359的u-boot移植问题

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Other Parts Discussed in Thread: AM3359

调试AM3359 NANDFLASH时，在drivers/mtd/nand/nand_base.c文件中，

函数static const struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
        struct nand_chip *chip,
        int busw,
        int *maf_id, int *dev_id,
        const struct nand_flash_dev *type)
{
int ret, maf_idx;
int tmp_id, tmp_manf;

/* Select the device */
chip->select_chip(mtd, 0);

/*
* Reset the chip, required by some chips (e.g. Micron MT29FxGxxxxx)
* after power-up
*/
chip->cmdfunc(mtd, NAND_CMD_RESET, -1, -1);

/* Send the command for reading device ID */
chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);

/* Read manufacturer and device IDs */
*maf_id = chip->read_byte(mtd);
*dev_id = chip->read_byte(mtd);

/* Try again to make sure, as some systems the bus-hold or other
* interface concerns can cause random data which looks like a
* possibly credible NAND flash to appear. If the two results do
* not match, ignore the device completely.
*/

chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);

/* Read manufacturer and device IDs */

tmp_manf = chip->read_byte(mtd);
tmp_id = chip->read_byte(mtd);

if (tmp_manf != *maf_id || tmp_id != *dev_id) {
  printk(KERN_INFO "%s: second ID read did not match "
         "%02x,%02x against %02x,%02x\n", __func__,
         *maf_id, *dev_id, tmp_manf, tmp_id);
  return ERR_PTR(-ENODEV);
}

if (!type)
type = nand_flash_ids;

for (; type->name != NULL; type++)
if (*dev_id == type->id)
break;

if (!type->name) {
  /* supress warning if there is no nand */
  if (*maf_id != 0x00 && *maf_id != 0xff &&
      *dev_id != 0x00 && *dev_id != 0xff)
   printk(KERN_INFO "%s: unknown NAND device: "
    "Manufacturer ID: 0x%02x, Chip ID: 0x%02x\n",
    __func__, *maf_id, *dev_id);
  return ERR_PTR(-ENODEV);
}

if (!mtd->name)
mtd->name = type->name;

chip->chipsize = (uint64_t)type->chipsize << 20;
chip->onfi_version = 0;

ret = nand_flash_detect_onfi(mtd, chip, &busw);
if (!ret)
nand_flash_detect_non_onfi(mtd, chip, type, &busw);

/* Get chip options, preserve non chip based options */
chip->options &= ~NAND_CHIPOPTIONS_MSK;
chip->options |= type->options & NAND_CHIPOPTIONS_MSK;

/*
* Set chip as a default. Board drivers can override it, if necessary
*/
chip->options |= NAND_NO_AUTOINCR;

/* Try to identify manufacturer */
for (maf_idx = 0; nand_manuf_ids[maf_idx].id != 0x0; maf_idx++) {
if (nand_manuf_ids[maf_idx].id == *maf_id)
break;
}

/*
* Check, if buswidth is correct. Hardware drivers should set
* chip correct !
*/
if (busw != (chip->options & NAND_BUSWIDTH_16)) {
  printk(KERN_INFO "NAND device: Manufacturer ID:"
         " 0x%02x, Chip ID: 0x%02x (%s %s)\n", *maf_id,
         *dev_id, nand_manuf_ids[maf_idx].name, mtd->name);
  printk(KERN_WARNING "NAND bus width %d instead %d bit\n",
         (chip->options & NAND_BUSWIDTH_16) ? 16 : 8,
         busw ? 16 : 8);
  return ERR_PTR(-EINVAL);
}

/* Calculate the address shift from the page size */
chip->page_shift = ffs(mtd->writesize) - 1;
/* Convert chipsize to number of pages per chip -1. */
chip->pagemask = (chip->chipsize >> chip->page_shift) - 1;

chip->bbt_erase_shift = chip->phys_erase_shift =
  ffs(mtd->erasesize) - 1;
if (chip->chipsize & 0xffffffff)
  chip->chip_shift = ffs((unsigned)chip->chipsize) - 1;
else
  chip->chip_shift = ffs((unsigned)(chip->chipsize >> 32)) + 31;

/* Set the bad block position */
chip->badblockpos = mtd->writesize > 512 ?
NAND_LARGE_BADBLOCK_POS : NAND_SMALL_BADBLOCK_POS;

/* Check if chip is a not a samsung device. Do not clear the
* options for chips which are not having an extended id.
*/
if (*maf_id != NAND_MFR_SAMSUNG && !type->pagesize)
chip->options &= ~NAND_SAMSUNG_LP_OPTIONS;

/* Check for AND chips with 4 page planes */
if (chip->options & NAND_4PAGE_ARRAY)
chip->erase_cmd = multi_erase_cmd;
else
chip->erase_cmd = single_erase_cmd;

/* Do not replace user supplied command function ! */
if (mtd->writesize > 512 && chip->cmdfunc == nand_command)
chip->cmdfunc = nand_command_lp;

MTDDEBUG (MTD_DEBUG_LEVEL0, "NAND device: Manufacturer ID:"
" 0x%02x, Chip ID: 0x%02x (%s %s)\n", *maf_id, *dev_id,
nand_manuf_ids[maf_idx].name, type->name);

return type;
}

里，程序停在for (; type->name != NULL; type++)
if (*dev_id == type->id)
break;

中，后printk关于type的值，发现并不是所传参数NULL，type值已发生改变，因此程序停在上面的for循环中，请问出现此问题的原因是什么？

13 年多前

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关于3359的u-boot移植问题