[PATCH] nand_wait : warn if the nand is busy on exit
matthieu.castet at parrot.com
Mon Nov 5 09:00:44 EST 2012
This patch allow to detect buggy driver/hardware with
bad RnB (dev_ready) management or when timeout occurs in polling mode.
This works when dev_ready is set or not set.
There are 2 methods to wait for an erase/program command completion:
1. Wait until nand RnB pin goes high (that's what chip->dev_ready usually does)
2. Poll the device: send a status (0x70) command and read status byte in a loop
until bit NAND_STATUS_READY is set
In all cases, you should send a status command after completion, to check if
the operation was successful. And if the operation completed, the status should
have bit NAND_STATUS_READY set.
Signed-off-by: Matthieu CASTET <matthieu.castet at parrot.com>
CC: Ivan Djelic <ivan.djelic at parrot.com>
drivers/mtd/nand/nand_base.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index ee49fe2..5894c2c 100644
@@ -865,6 +865,8 @@ static int nand_wait(struct mtd_info *mtd, struct nand_chip *chip)
status = (int)chip->read_byte(mtd);
+ /* This can happen if in case of timeout or buggy dev_ready */
+ WARN_ON(!(status & NAND_STATUS_READY));
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