[U-Boot] [PATCH] spi: zynq_spi: Fix infinite looping while xfer

[Jagan Teki]

On 23 June 2016 at 19:28, Lad, Prabhakar <prabhakar.csengg at gmail.com> wrote:
> During spi transfer, for example:
> sspi 1:1.0 8 ff
>
> the rx_len values will  be:
> rx_len = 0
> rx_len = 4294967295

Does these number during 'sspi' or during data transfer? why rx_len is
4294967295?

>
> This caused a busy looping during xfer, this patch fixes it
> by adding a check while reading the rx fifo
>
> Signed-off-by: Lad, Prabhakar <Prabhakar.Lad at racelogic.co.uk>
> Cc: Michal Simek <michal.simek at xilinx.com>
> Cc: Siva Durga Prasad Paladugu <sivadur at xilinx.com>
> Cc: Jagan Teki <jteki at openedev.com>
> ---
>  drivers/spi/zynq_spi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/spi/zynq_spi.c b/drivers/spi/zynq_spi.c
> index 09ae1be..dd3de27 100644
> --- a/drivers/spi/zynq_spi.c
> +++ b/drivers/spi/zynq_spi.c
> @@ -230,7 +230,7 @@ static int zynq_spi_xfer(struct udevice *dev,
> unsigned int bitlen,
>
>          /* Read the data from RX FIFO */
>          status = readl(&regs->isr);
> -        while (status & ZYNQ_SPI_IXR_RXNEMPTY_MASK) {
> +        while ((status & ZYNQ_SPI_IXR_RXNEMPTY_MASK) && rx_len) {
>              buf = readl(&regs->rxdr);
>              if (rx_buf)
>                  *rx_buf++ = buf;

-- 
Jagan.