On Wed, 2015-05-20 at 20:03 -0700, Andrei Yakimov wrote:
> On Wed, 2015-05-20 at 21:46 -0500, Scott Wood wrote:
> > On Wed, 2015-05-20 at 19:42 -0700, Andrei Yakimov wrote:
> > > For now lets stick with 1536 in u-boot.
> > > I will send a patch.
> > > At least it will not loosing flash over time
> > > as nand ages.
> > >
> > > I understand what you wish, and will take a look
> > > on it inside fresh new kernel. I found one more driver -
> > > marvel looks like have same problem.
> > > I will check how NAND_CMD_RNDOUT is working.
> > > Perhaps we do not need extra read_param(),
> > > and use only NAND_CMD_RNDOUT to get next
> > > block inside page loop.
> >
> > Again, I'm a reluctant to use RNDOUT in the default read_param() because
> > that would change the flow for all controllers and chips, and while the
> > chip manual I'm looking at says it's OK, it introduces risk that it
> > doesn't work everywhere (e.g. some controller drivers that provide their
> > own cmdfunc don't implement RNDOUT).
RNDOUT is already used by nand_flash_detect_ext_param_page(), so this
isn't as much of a concern for ONFI, but it could be an issue with
nand_flash_detect_jedec().
> Forget about read_param(),
Then how will it work on controllers like eLBC/IFC which is the whole
point?
> just like this:
> for (i = 0; i < 3; i++) {
> for (j = 0; j < sizeof(*p); j++)
> ((uint8_t *)p)[j] = chip->read_byte(mtd);
> if (onfi_crc16(ONFI_CRC_BASE, (uint8_t *)p, 254) ==
> le16_to_cpu(p->crc)) {
> break;
> }
> chip->cmdfunc(mtd, NAND_CMD_RNDOUT, 0, -1);
> }
>
>
> and this is good - will be "no op" or "bad command" error,
> which could be ignored - so for this drivers operation flow is
> unchanged.
RNDOUT needs to come before read_buf() and it needs to specify the
offset you want.
-Scott
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