On 19/04/2023 08:06, Jaewon Kim wrote:
> Adds cpu_relax() to prevent long busy-wait.
How cpu_relax prevents long waiting?
> There is busy-wait loop to check data transfer completion in polling mode.
>
> Signed-off-by: Jaewon Kim <jaewon02.kim@xxxxxxxxxxx>
> ---
> drivers/spi/spi-s3c64xx.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index 273aa02322d9..886722fb40ea 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -568,6 +568,7 @@ static int s3c64xx_wait_for_pio(struct s3c64xx_spi_driver_data *sdd,
>
> val = msecs_to_loops(ms);
> do {
> + cpu_relax();
Shouldn't this be just readl_poll_timeout()? Or the syntax would be too
complicated?
> status = readl(regs + S3C64XX_SPI_STATUS);
> } while (RX_FIFO_LVL(status, sdd) < xfer->len && --val);
>
Best regards,
Krzysztof
