On 11/05/2011 03:24 AM, Marek Vasut wrote:
> There is a problem reported that the NAND_NO_SUBPAGE_WRITE, set by some
> drivers,
> is silently ignored by NAND core. This causes UBI to malfunction on these
> drivers, because UBI tries to use subpage writes.
>
Hi Marek,
> This was discussed already with no conclusion, see thread:
> Message-Id: <1302372335-30232-6-git-send-email-sba...@denx.de>
Right, there was some discussion also comparing what it is done on the
Linux Kernel. There is a discrepancy for the usage of the
NAND_NO_SUBPAGE_WRITE, because it belongs to the chip options, but in
this case (and in the patch I submitted) it is used as "controller"
option. Same case here.
>
> The bug was recently retriggered by Veli-Pekka Peltola, causing him trouble
> with
> UBI on the MX28 CPU:
> Message-ID: <4eb3e4ea.9080...@bluegiga.com>
> drivers/mtd/nand/nand_base.c | 11 +++++++++++
> 1 files changed, 11 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index 6aac6a2..7ecd5a3 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -2548,6 +2548,7 @@ static const struct nand_flash_dev
> *nand_get_flash_type(struct mtd_info *mtd,
> {
> int ret, maf_idx;
> int tmp_id, tmp_manf;
> + int no_subpage = 0;
>
> /* Select the device */
> chip->select_chip(mtd, 0);
> @@ -2612,10 +2613,20 @@ static const struct nand_flash_dev
> *nand_get_flash_type(struct mtd_info *mtd,
> if (!ret)
> nand_flash_detect_non_onfi(mtd, chip, type, &busw);
>
> + /*
> + * If the controller is incapable of subpage writes, force no subpage
> + * writes. This has to be done here, otherwise UBI will complain.
> + */
> + if (chip->options & NAND_NO_SUBPAGE_WRITE)
> + no_subpage = 1;
> +
The patch does not convince me. This relies only if the SUBPAGE_WRITE is
supported by the chip, and this is half problem. What happens if we have
a SLC (that generally supports subpage mode) connected to a controller
that does not support it ? NAND_NO_SUBPAGE_WRITE is not set, but the
controller can't manage it.
I think your patch fix only a particular case, and it is not general enough.
Best regards,
Stefano Babic
--
=====================================================================
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: off...@denx.de
=====================================================================
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
