mtd: rawnand: brcmnand: Fix potential false time out warning

Backport from the Linux kernel:
commit 9cc0a598b944816f2968baf2631757f22721b996
"mtd: rawnand: brcmnand: Fix potential false time out warning"

If system is busy during the command status polling function, the driver
may not get the chance to poll the status register till the end of time
out and return the premature status.  Do a final check after time out
happens to ensure reading the correct status.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20230706182909.79151-3-william.zhang@broadcom.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: William Zhang <william.zhang@broadcom.com>

diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
index 700d1122639f0cf9c7f08996866bb6b8cde7ed98..46a4107a83a9eb320407f2ccc40c111144ec9cdd 100644 (file)
--- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
+++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
@@ -1011,6 +1011,14 @@ static int bcmnand_ctrl_poll_status(struct brcmnand_controller *ctrl,
        } while (get_timer(base) < limit);
 #endif /* __UBOOT__ */
 
+       /*
+        * do a final check after time out in case the CPU was busy and the driver
+        * did not get enough time to perform the polling to avoid false alarms
+        */
+       val = brcmnand_read_reg(ctrl, BRCMNAND_INTFC_STATUS);
+       if ((val & mask) == expected_val)
+               return 0;
+
        dev_warn(ctrl->dev, "timeout on status poll (expected %x got %x)\n",
                 expected_val, val & mask);