mtd: nand: fix interpretation of NAND_CMD_NONE in nand_command[_lp]()

[ 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index a0b0302..528e04f 100644 (file)
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -710,7 +710,8 @@ 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;
@@ -739,6 +740,7 @@ 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:
@@ -832,7 +834,9 @@ 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;
@@ -868,6 +872,7 @@ 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: