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

Hector Palacios hector.palacios at digi.com
Fri Jul 15 09:45:03 CEST 2016


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 at 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) {
@@ -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;


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