[PATCH 05/13] tty: serial: samsung: add gs101 earlycon support

Tudor Ambarus
2023-12-14T10:52:58Z

GS101 only allows 32-bit register accesses. If using 8-bit register
accesses on gs101, a SError Interrupt is raised causing the system
unusable.

Force the reg accesses to MMIO32 regardless of the user's settings.
This is a common practice for such earlycons (bcm2835aux, uniphier,
lpuart32), in order to avoid crashing the kernel with a wrong early
console definition.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
---
drivers/tty/serial/samsung_tty.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c
index 66bd6c090ace..19cd3e6a9b6e 100644
--- a/drivers/tty/serial/samsung_tty.c
+++ b/drivers/tty/serial/samsung_tty.c
@@ -2787,6 +2787,17 @@ OF_EARLYCON_DECLARE(exynos4210, "samsung,exynos4210-uart",
OF_EARLYCON_DECLARE(artpec8, "axis,artpec8-uart",
s5pv210_early_console_setup);

+static int __init gs101_early_console_setup(struct earlycon_device *device,
+ const char *opt)
+{
+ /* gs101 always expects MMIO32 register accesses. */
+ device->port.iotype = UPIO_MEM32;
+
+ return s5pv210_early_console_setup(device, opt);
+}
+
+OF_EARLYCON_DECLARE(gs101, "google,gs101-uart", gs101_early_console_setup);
+
/* Apple S5L */
static int __init apple_s5l_early_console_setup(struct earlycon_device *device,
const char *opt)
--
2.43.0.472.g3155946c3a-goog