HI Akshay,
On 3 June 2014 06:37, Akshay Saraswat <aksha...@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 <aksha...@samsung.com>
Acked-by: Simon Glass <s...@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
>
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