Hello Krzysztof,
Krzysztof Kozlowski wrote:
> If DMA is not available (even when configured in DeviceTree), the driver
> will fail the startup procedure thus making serial console not
> available.
>
> For example this causes boot failure on QEMU ARMv7 (Exynos4210, SMDKC210):
> [ 1.302575] OF: amba_device_add() failed (-19) for /amba/pdma@12680000
> ...
> [ 11.435732] samsung-uart 13800000.serial: DMA request failed
> [ 72.963893] samsung-uart 13800000.serial: DMA request failed
> [ 73.143361] Kernel panic - not syncing: Attempted to kill init! exitcode=00000000
>
> DMA is not necessary for serial to work, so continue with UART startup
> after emitting a warning.
>
> Fixes: Fixes: 62c37eedb74c ("serial: samsung: add dma reqest/release functions")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> ---
> drivers/tty/serial/samsung.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
> index b4f86c219db1..7a17aedbf902 100644
> --- a/drivers/tty/serial/samsung.c
> +++ b/drivers/tty/serial/samsung.c
> @@ -1031,8 +1031,10 @@ static int s3c64xx_serial_startup(struct uart_port *port)
> if (ourport->dma) {
> ret =3c24xx_serial_request_dma(ourport);
> if (ret < 0) {
> - dev_warn(port->dev, "DMA request failed\n");
> - return ret;
> + dev_warn(port->dev,
> + "DMA request failed, DMA will not be used\n");
> + devm_kfree(port->dev, ourport->dma);
> + ourport->dma =ULL;
This line looks odd. Did you want to assign NULL here?
Also, whitespace on both sides of '='?
- Tobias
> }
> }
>
>