[PATCH v2 3/3] spi: rockchip: Fix error in SPI slave pio read

[Emil Renner Berthing]

On Wed, 22 Jul 2020 at 10:38, Jon Lin <jon.lin at rock-chips.com> wrote:
>
> The RXFLR is possible larger than rx_left in Rockchip SPI, fix it.
>
> Signed-off-by: Jon Lin <jon.lin at rock-chips.com>
> Reviewed-by: Heiko Stuebner <heiko at sntech.de>

In addition to my review and test you should probably also add
Fixes: 01b59ce5dac8 ("spi: rockchip: use irq rather than polling")
..so this will be picked up in the stable trees

/Emil

> ---
>  drivers/spi/spi-rockchip.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
> index a451dacab5cf..75a8a9428ff8 100644
> --- a/drivers/spi/spi-rockchip.c
> +++ b/drivers/spi/spi-rockchip.c
> @@ -291,7 +291,7 @@ static void rockchip_spi_pio_writer(struct rockchip_spi *rs)
>  static void rockchip_spi_pio_reader(struct rockchip_spi *rs)
>  {
>         u32 words = readl_relaxed(rs->regs + ROCKCHIP_SPI_RXFLR);
> -       u32 rx_left = rs->rx_left - words;
> +       u32 rx_left = (rs->rx_left > words) ? rs->rx_left - words : 0;
>
>         /* the hardware doesn't allow us to change fifo threshold
>          * level while spi is enabled, so instead make sure to leave
> --
> 2.17.1
>
>
>
>
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