Re: [PATCH v3 2/5] mtd: rawnand: brcmnand: Fix potential false time out warning

[Miquel Raynal]

Hi William,

william.zhang@xxxxxxxxxxxx wrote on Tue, 27 Jun 2023 12:37:35 -0700:

> 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.
> 
> Fixes: 9d2ee0a60b8b ("mtd: nand: brcmnand: Check flash #WP pin status before nand erase/program")
> Signed-off-by: William Zhang <william.zhang@xxxxxxxxxxxx>
> Reviewed-by: Florian Fainelli <florian.fainelli@xxxxxxxxxxxx>

Cc: stable here and in patch 1 as well.

> ---
> 
> Changes in v3: None
> Changes in v2: None
> 
>  drivers/mtd/nand/raw/brcmnand/brcmnand.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> index 69709419516a..37c2c7cfa00e 100644
> --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c
> @@ -1080,6 +1080,14 @@ static int bcmnand_ctrl_poll_status(struct brcmnand_controller *ctrl,
>  		cpu_relax();
>  	} while (time_after(limit, jiffies));
>  
> +	/*
> +	 * do a final check after time out in case CPU is busy and driver does
> +	 * not get the enough time to poll to avoid false alarm

Do a final... ...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);
>  

Otherwise looks good.

Thanks,
Miquèl