[U-Boot] [RFC PATCH 1/1] mtd: nand: fix bug writing 1 byte less than page size

[Scott Wood <oss@buserror.net>]

On Fri, 2016-07-15 at 09:45 +0200, Hector Palacios wrote:
> nand_do_write_ops() determines if it is writing a partial page with the
> formula:
> 	part_pagewr = (column || writelen < (mtd->writesize - 1))
> 
> When 'writelen' is exactly 1 byte less than the NAND page size the formula
> equates to zero, so the code doesn't process it as a partial write, although
> it should.
> As a consequence the function remains in the while(1) loop with 'writelen'
> becoming 0xffffffff and iterating until the watchdog timeout triggers.
> 
> To reproduce the issue on a NAND with 2K page (0x800):
> 	=> nand erase.part <partition>
> 	=> nand write $loadaddr <partition> 7ff
> 
> Signed-off-by: Hector Palacios <hector.palacios@digi.com>
> ---
> ?drivers/mtd/nand/nand_base.c | 4 ++--
> ?1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
> index 689716753ae6..c8be74849e56 100644
> --- a/drivers/mtd/nand/nand_base.c
> +++ b/drivers/mtd/nand/nand_base.c
> @@ -877,7 +877,7 @@ static int nand_wait(struct mtd_info *mtd, struct
> nand_chip *chip)
> ?
> ??	u32 timer = (CONFIG_SYS_HZ * timeo) / 1000;
> ??	u32 time_start;
> -?
> +
> ??	time_start = get_timer(0);
> ??	while (get_timer(time_start) < timer) {
> ?		if (chip->dev_ready) {

This change is unrelated.

> @@ -2411,7 +2411,7 @@ static int nand_do_write_ops(struct mtd_info *mtd,
> loff_t to,
> ?		int cached = writelen > bytes && page != blockmask;
> ?		uint8_t *wbuf = buf;
> ?		int use_bufpoi;
> -		int part_pagewr = (column || writelen < (mtd->writesize -
> 1));
> +		int part_pagewr = (column || writelen < mtd->writesize);
> ?
> ?		if (part_pagewr)
> ?			use_bufpoi = 1;
> 

Could you send a non-RFC patch? ?This also needs to get fixed in Linux.

-Scott