[PATCH AUTOSEL for 4.9 183/219] mtd: nand: fix interpretation of NAND_CMD_NONE in nand_command[_lp]()

Sasha Levin
2018-03-03T23:30:06Z

From: Miquel Raynal <miquel.raynal@free-electrons.com>

[ Upstream commit df467899da0b71465760b4e35127bce837244eee ]

Some drivers (like nand_hynix.c) call ->cmdfunc() with NAND_CMD_NONE
and a column address and expect the controller to only send address
cycles. Right now, the default ->cmdfunc() implementations provided by
the core do not filter out the command cycle in this case and forwards
the request to the controller driver through the ->cmd_ctrl() method.
The thing is, NAND controller drivers can get this wrong and send a
command cycle with a NAND_CMD_NONE opcode and since NAND_CMD_NONE is
-1, and the command field is usually casted to an u8, we end up sending
the 0xFF command which is actually a RESET operation.

Add conditions in nand_command[_lp]() functions to sending the initial
command cycle when command == NAND_CMD_NONE.

Signed-off-by: Miquel Raynal <miquel.raynal@free-electrons.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/mtd/nand/nand_base.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 21c03086bb7f..a3e86e52640a 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -715,7 +715,8 @@ static void nand_command(struct mtd_info *mtd, unsigned int command,
chip->cmd_ctrl(mtd, readcmd, ctrl);
ctrl &= ~NAND_CTRL_CHANGE;
}
- chip->cmd_ctrl(mtd, command, ctrl);
+ if (command != NAND_CMD_NONE)
+ chip->cmd_ctrl(mtd, command, ctrl);

/* Address cycle, when necessary */
ctrl = NAND_CTRL_ALE | NAND_CTRL_CHANGE;
@@ -744,6 +745,7 @@ static void nand_command(struct mtd_info *mtd, unsigned int command,
*/
switch (command) {

+ case NAND_CMD_NONE:
case NAND_CMD_PAGEPROG:
case NAND_CMD_ERASE1:
case NAND_CMD_ERASE2:
@@ -806,7 +808,9 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
}

/* Command latch cycle */
- chip->cmd_ctrl(mtd, command, NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);
+ if (command != NAND_CMD_NONE)
+ chip->cmd_ctrl(mtd, command,
+ NAND_NCE | NAND_CLE | NAND_CTRL_CHANGE);

if (column != -1 || page_addr != -1) {
int ctrl = NAND_CTRL_CHANGE | NAND_NCE | NAND_ALE;
@@ -842,6 +846,7 @@ static void nand_command_lp(struct mtd_info *mtd, unsigned int command,
*/
switch (command) {

+ case NAND_CMD_NONE:
case NAND_CMD_CACHEDPROG:
case NAND_CMD_PAGEPROG:
case NAND_CMD_ERASE1:
--
2.14.1