Re: [PATCH v3 2/5] mtd: spi-nor: Set all BP bits to one when lock_len == mtd->size

[Jungseung Lee <js07.lee@xxxxxxxxxxx>]

On Mon, 2020-03-23 at 09:24 +0000, Tudor.Ambarus@xxxxxxxxxxxxx wrote:
> From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
> 
> When there are more BP settings than needed for defining the
> protected
> areas of the flash memory, most flashes will define the remaining
> settings as "protect all", i.e. the equivalent of having all the BP
> bits
> set to one. But there are flashes where the in-between BP values
> are undefined (not mentioned), and only the "all bits set" is
> protecting
> the entire memory. One such example is w25q80, where BP[2:0]=0b101
> and
> 0b110 are not defined.
> 
> Set all the BP bits to one when lock_len == mtd->size, to treat this
> special case.
> 
> Suggested-by: Michael Walle <michael@xxxxxxxx>
> Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
> ---
>  drivers/mtd/spi-nor/core.c | 20 +++++++++++++-------
>  1 file changed, 13 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
> index 36660068bc04..3788a95c0a47 100644
> --- a/drivers/mtd/spi-nor/core.c
> +++ b/drivers/mtd/spi-nor/core.c
> @@ -1660,13 +1660,19 @@ static int spi_nor_sr_lock(struct spi_nor
> *nor, loff_t ofs, uint64_t len)
>  	 *
>  	 *   pow = ceil(log2(size / len)) = log2(size) -
> floor(log2(len)) + 1
>  	 */
> -	pow = ilog2(mtd->size) - ilog2(lock_len) + 1;
> -	val = mask - (pow << SR_BP_SHIFT);
> -	if (val & ~mask)
> -		return -EINVAL;
> -	/* Don't "lock" with no region! */
> -	if (!(val & mask))
> -		return -EINVAL;
> +	if (lock_len == mtd->size) {
> +		val = mask;
> +	} else {
> +		pow = ilog2(mtd->size) - ilog2(lock_len) + 1;
> +		val = mask - (pow << SR_BP_SHIFT);
> +
> +		if (val & ~mask)
> +			return -EINVAL;
> +
> +		/* Don't "lock" with no region! */
> +		if (!(val & mask))
> +			return -EINVAL;
> +	}
>  
>  	status_new = (status_old & ~mask & ~tb_mask) | val;
>  

Reviewed-by: Jungseung Lee <js07.lee@xxxxxxxxxxx>


______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/