spi: rockchip: Fix error in SPI slave pio read
authorJon Lin <jon.lin@rock-chips.com>
Thu, 23 Jul 2020 00:43:56 +0000 (08:43 +0800)
committerMark Brown <broonie@kernel.org>
Tue, 28 Jul 2020 16:29:31 +0000 (17:29 +0100)
The RXFLR is possible larger than rx_left in Rockchip SPI, fix it.

Fixes: 01b59ce5dac8 ("spi: rockchip: use irq rather than polling")
Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
Tested-by: Emil Renner Berthing <kernel@esmil.dk>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Emil Renner Berthing <kernel@esmil.dk>
Link: https://lore.kernel.org/r/20200723004356.6390-3-jon.lin@rock-chips.com
Signed-off-by: Mark Brown <broonie@kernel.org>
drivers/spi/spi-rockchip.c

index a451dac..75a8a94 100644 (file)
@@ -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