A question about nand_read()

[Patrick Turley]

No love? Is my question too n00bish?

On Tue, 18 Nov 2008 18:43:55 -0600, Patrick Turley  
<patrick.turley at freescale.com> wrote:

> My tree is up-to-date as I'm writing this message.
>
> I'm looking at nand_read() in nand_base.c, starting at line 1175, quoted
> here for your convenience:
>
>
> static int nand_read(struct mtd_info *mtd, loff_t from, size_t len,
>                       size_t *retlen, uint8_t *buf)
> {
>          struct nand_chip *chip = mtd->priv;
>          int ret;
>
>          /* Do not allow reads past end of device */
>          if ((from + len) > mtd->size)
>                  return -EINVAL;
>          if (!len)
>                  return 0;
>
>          nand_get_device(chip, mtd, FL_READING);
>
>          chip->ops.len = len;
>          chip->ops.datbuf = buf;
>          chip->ops.oobbuf = NULL;
>
>          ret = nand_do_read_ops(mtd, from, &chip->ops);
>
>          *retlen = chip->ops.retlen;
>
>          nand_release_device(mtd);
>
>          return ret;
> }
>
>
> In particular, I'm looking at the preparation to call nand_do_read_ops(),
> where the chip->ops structure is filled in.
>
> Here's a small excerpt from nand_do_read_ops() that concerns me:
>
>
>      /* Now read the page into the buffer */
>      if (unlikely(ops->mode == MTD_OOB_RAW))
>              ret = chip->ecc.read_page_raw(mtd, chip, bufpoi);
>      else if (!aligned && NAND_SUBPAGE_READ(chip) && !oob)
>              ret = chip->ecc.read_subpage(mtd, chip, col, bytes, bufpoi);
>      else
>              ret = chip->ecc.read_page(mtd, chip, bufpoi);
>      if (ret < 0)
>              break;
>
>
> Note that nand_do_read_ops() will look at the mode field of the ops
> structure, but this field hasn't been set by nand_read().
>
> On the face of it, this looks like a bug. Is there something I don't know
> that makes this not a bug? For example, is the value in the mode field
> intended to persist across operations?
>
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