From: Matthieu CASTET Date: Mon, 5 Nov 2012 14:00:44 +0000 (+0100) Subject: mtd: nand_wait: warn if the nand is busy on exit X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f251b8dfdd0721255ea11751cdc282834e43b74e;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git 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 Signed-off-by: Artem Bityutskiy --- diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c index 1d5c951ebcb0..01505406ca7b 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; }