[PATCH 2/3] tty: serial: samsung: Fix A7-A11 serial earlycon SError
From: Nick Chan <hidden>
Date: 2024-09-08 07:59:39
Also in:
asahi, linux-samsung-soc, linux-serial, lkml
Subsystem:
arm/samsung s3c, s5p and exynos arm architectures, the rest, tty layer and serial drivers · Maintainers:
Krzysztof Kozlowski, Peter Griffin, Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
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. Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org> Signed-off-by: Nick Chan <redacted> --- drivers/tty/serial/samsung_tty.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index c4f2ac9518aa..7574d4176e76 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,
@@ -2822,6 +2822,9 @@ OF_EARLYCON_DECLARE(gs101, "google,gs101-uart", gs101_early_console_setup); static int __init apple_s5l_early_console_setup(struct earlycon_device *device, const char *opt) { + /* Apple A7-A11 requires MMIO32 register accesses. */ + device->port.iotype = UPIO_MEM32; + /* Close enough to S3C2410 for earlycon... */ device->port.private_data = &s3c2410_early_console_data;
--
2.46.0