[U-Boot] [PATCH v2 1/5] Exynos: SPI: Fix reading data from SPI flash

[Simon Glass]

HI Akshay,

On 3 June 2014 06:37, Akshay Saraswat <akshay.s at samsung.com> wrote:
> SPI recieve and transfer code in exynos_spi driver has a logical bug.
> We read data in a variable which can hold an integer. Then we assign
> this integer 32 bit value to another variable which has data type uchar.
> Latter represents a unit of our recieve buffer. Everytime when we write
> a value to our recieve buffer we step ahead by 4 units when actually we
> wrote to one unit. This results in the loss of 3 bytes out of every 4
> bytes recieved. This patch intends to fix this bug.
>
> Signed-off-by: Akshay Saraswat <akshay.s at samsung.com>

Acked-by: Simon Glass <sjg at chromium.org>

(see comment below - could update this patch or do a follow-on to
improve speed of both tx and rx)

> ---
> Changes since v1:
>         - Added check for step.
>
>  drivers/spi/exynos_spi.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/spi/exynos_spi.c b/drivers/spi/exynos_spi.c
> index 4d5def2..68d1206 100644
> --- a/drivers/spi/exynos_spi.c
> +++ b/drivers/spi/exynos_spi.c
> @@ -302,6 +302,11 @@ static int spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo,
>                                         }
>                                 } else {
>                                         if (rxp || stopping) {
> +                                               if (step == 4) {
> +                                                       *(rxp + 3) = temp >> 24;
> +                                                       *(rxp + 2) = temp >> 16;
> +                                                       *(rxp + 1) = temp >> 8;
> +                                               }

BTW I just had another look at the code - sorry I didn't notice this
before, but you know that rxp is word-aligned so you can just do
*((uint32_t *)rxp) = temp;

>                                                 *rxp = temp;
>                                                 rxp += step;
>                                         }
> --
> 1.7.12.4
>