From patchwork Mon Nov 5 14:00:44 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: nand_wait : warn if the nand is busy on exit Date: Mon, 05 Nov 2012 04:00:44 -0000 From: Matthieu CASTET X-Patchwork-Id: 197203 Message-Id: <1352124044-31627-1-git-send-email-matthieu.castet@parrot.com> To: linux-mtd@lists.infradead.org Cc: Ivan Djelic , Matthieu CASTET , dedekind1@gmail.com 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 CC: Ivan Djelic --- 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 --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -865,6 +865,8 @@ static int nand_wait(struct mtd_info *mtd, struct nand_chip *chip) 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; }