[U-Boot] [PATCH 2/2] mtd: nand: nand_base.c: Fix address cycle problem with NAND_CMD_RNDOUT

[Stefan Roese]

From: Pekon Gupta <pekon at ti.com>

On some NAND devices (e.g. Hynix H27U2G8F2CTR-BI on Siemens DXR2 /
Draco boards) the SPL issues the following bit-flip error messages:

nand: bit-flip corrected @oob=0
...

This patch makes sure that only the required address cycles are sent
to the NAND chip.

The same issue has been reported by Bacem Daassi:

http://e2e.ti.com/support/arm/sitara_arm/f/791/t/259699.aspx

"
The issue is mainly due to a NAND protocol violation in the omap driver since
the Random Data Output command (05h-E0h) expects to see only the column address
that should be addressed within the already loaded read page into the read
buffer. Only 2 address cycles with ALE active should be provided between the
05h and E0h commands. The Page read command expects the full address footprint
(2bytes for column address + 3bytes for row address), but once the page is
loaded into the read buffer, Random Data Output should be used with only 2bytes
for column address.
"

Signed-off-by: Pekon Gupta <pekon at ti.com>
Signed-off-by: Stefan Roese <sr at denx.de>
Tested-by: Samuel Egli <samuel.egli at siemens.com>
Cc: Marek Belisko <marek.belisko at gmail.com>
Cc: Scott Wood <scottwood at freescale.com>
---
 drivers/mtd/nand/nand_base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 1ce55fd..f11fce4 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -674,7 +674,7 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
 			ctrl &= ~NAND_CTRL_CHANGE;
 			chip->cmd_ctrl(mtd, column >> 8, ctrl);
 		}
-		if (page_addr != -1) {
+		if (page_addr != -1 && command != NAND_CMD_RNDOUT) {
 			chip->cmd_ctrl(mtd, page_addr, ctrl);
 			chip->cmd_ctrl(mtd, page_addr >> 8,
 				       NAND_NCE | NAND_ALE);
-- 
1.9.2