mtd: nand_wait: warn if the nand is busy on exit
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@parrot.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 1d5c951..0150540 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -865,6 +865,8 @@
led_trigger_event(nand_led_trigger, LED_OFF);
status = (int)chip->read_byte(mtd);
+ /* This can happen if in case of timeout or buggy dev_ready */
+ WARN_ON(!(status & NAND_STATUS_READY));
return status;
}