On 07/09/2024 13:06, Nick Chan wrote:
> Apple's earlier SoCs, like A7-A11, requires 32-bit writes for the serial
> port. Otherwise, a SError happens when writing to UTXH (+0x20). This only
> manifested in earlycon as reg-io-width in the device tree is consulted
> for normal serial writes.
>
> Change the iotype of the port to UPIO_MEM32, to allow the serial port to
> function on A7-A11 SoCs. This change does not appear to affect Apple M1 and
> above.
>
> Signed-off-by: Nick Chan <towinchenmi@xxxxxxxxx>
> ---
> drivers/tty/serial/samsung_tty.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
> index c4f2ac9518aa..27b8a50bd3e7 100644
> --- a/drivers/tty/serial/samsung_tty.c
> +++ b/drivers/tty/serial/samsung_tty.c
> @@ -2536,7 +2536,7 @@ static const struct s3c24xx_serial_drv_data s5l_serial_drv_data = {
> .name = "Apple S5L UART",
> .type = TYPE_APPLE_S5L,
> .port_type = PORT_8250,
> - .iotype = UPIO_MEM,
> + .iotype = UPIO_MEM32,
> .fifosize = 16,
> .rx_fifomask = S3C2410_UFSTAT_RXMASK,
> .rx_fifoshift = S3C2410_UFSTAT_RXSHIFT,
> @@ -2825,8 +2825,10 @@ static int __init apple_s5l_early_console_setup(struct earlycon_device *device,
> /* Close enough to S3C2410 for earlycon... */
> device->port.private_data = &s3c2410_early_console_data;
>
> + /* ... however, we need to change the port iotype */
> + device->port.iotype = UPIO_MEM32;
If there is going to be resend, then this comment is redundant and can
be dropped - repeats the code and does not provide any explanation why.
Which would also make the patch smaller and easier to read. See GS101
earlycon.
Reviewed-by: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
Best regards,
Krzysztof
