[PATCH] mtd: r852: make ecc_reg 32-bit in r852_ecc_correct

[PATCH] mtd: r852: make ecc_reg 32-bit in r852_ecc_correct

[Nicolas Iooss]

r852_ecc_correct() reads a 32-bit register into a 16-bit variable,
ecc_reg, but this variable is later used as if it was larger.  This is
reported by clang when building the kernel with many warnings:

    drivers/mtd/nand/r852.c:512:11: error: shift count >= width of type
    [-Werror,-Wshift-count-overflow]
                    ecc_reg >>= 16;
                            ^   ~~
Fix this by making ecc_reg 32-bit, like the return type of
r852_read_reg_dword().

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
---

As I haven't got the hardware to test this patch, it is only compile-tested.

 drivers/mtd/nand/r852.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/nand/r852.c b/drivers/mtd/nand/r852.c
index 77e96d2df96c..cc6bac537f5a 100644
--- a/drivers/mtd/nand/r852.c
+++ b/drivers/mtd/nand/r852.c
@@ -466,7 +466,7 @@ static int r852_ecc_calculate(struct mtd_info *mtd, const uint8_t *dat,
 static int r852_ecc_correct(struct mtd_info *mtd, uint8_t *dat,
 				uint8_t *read_ecc, uint8_t *calc_ecc)
 {
-	uint16_t ecc_reg;
+	uint32_t ecc_reg;
 	uint8_t ecc_status, err_byte;
 	int i, error = 0;
 
-- 
2.4.5

Re: [PATCH] mtd: r852: make ecc_reg 32-bit in r852_ecc_correct

[Brian Norris]

On Sun, Jul 05, 2015 at 09:57:41AM +0800, Nicolas Iooss wrote:
> r852_ecc_correct() reads a 32-bit register into a 16-bit variable,
> ecc_reg, but this variable is later used as if it was larger.  This is
> reported by clang when building the kernel with many warnings:
> 
>     drivers/mtd/nand/r852.c:512:11: error: shift count >= width of type
>     [-Werror,-Wshift-count-overflow]
>                     ecc_reg >>= 16;
>                             ^   ~~
> Fix this by making ecc_reg 32-bit, like the return type of
> r852_read_reg_dword().
> 
> Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
> ---
> 
> As I haven't got the hardware to test this patch, it is only compile-tested.

Looks good to me. Pushed to l2-mtd.git.

Thanks,
Brian

>  drivers/mtd/nand/r852.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/nand/r852.c b/drivers/mtd/nand/r852.c
> index 77e96d2df96c..cc6bac537f5a 100644
> --- a/drivers/mtd/nand/r852.c
> +++ b/drivers/mtd/nand/r852.c
> @@ -466,7 +466,7 @@ static int r852_ecc_calculate(struct mtd_info *mtd, const uint8_t *dat,
>  static int r852_ecc_correct(struct mtd_info *mtd, uint8_t *dat,
>  				uint8_t *read_ecc, uint8_t *calc_ecc)
>  {
> -	uint16_t ecc_reg;
> +	uint32_t ecc_reg;
>  	uint8_t ecc_status, err_byte;
>  	int i, error = 0;
>  
> -- 
> 2.4.5
>