Hi J,
On Tue, 18 Feb 2025 at 08:55, J. Neuschäfer via B4 Relay
<devnull+j.ne.posteo....@kernel.org> wrote:
>
> From: "J. Neuschäfer" <j...@posteo.net>
>
> On some platforms, initializing the watchdog driver enables a timer
> interrupt. This of course requires the interrupt handlers to be
> properly initialized, otherwise U-Boot may crash or run the timer
> interrupt handler of a previous bootloader stage.
>
> To account for such systems, always initialize interrupts
> (arch_initr_trap) before the watchdog (initr_watchdog).
>
> This problem was observed on a PowerPC MPC83xx board.
>
> Signed-off-by: J. Neuschäfer <j...@posteo.net>
> ---
> NOTE: This approach seems safe and fine to me, but an argument could be
> made that this should be fixed in the platform-specific drivers
> instead. Please let me know what you think.
>
>
> Rough stack trace (not sure if it should be part of the commit message):
>
> initr_watchdog (drivers/watchdog/wdt-uclass.c)
> device_probe(wdt@200)
> device_probe(timer)
> mpc8xxx_wdt_start (drivers/watchdog/mpc8xxx_wdt.c)
> set_msr(get_msr() | MSR_EE);
>
> arch_initr_trap (arch/powerpc/lib/traps.c)
> trap_init (arch/powerpc/cpu/mpc83xx/start.S)
> ---
> common/board_r.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/common/board_r.c b/common/board_r.c
> index
> 179259b00de81f7ba9802fc5288e7c2b6e6f381a..f711cd237ae76d80ca2413017bfe131656f44180
> 100644
> --- a/common/board_r.c
> +++ b/common/board_r.c
> @@ -652,11 +652,11 @@ static init_fnc_t init_sequence_r[] = {
> serial_initialize,
> initr_announce,
> dm_announce,
> + arch_initr_trap,
> #if CONFIG_IS_ENABLED(WDT)
> initr_watchdog,
> #endif
> INIT_FUNC_WATCHDOG_RESET
> - arch_initr_trap,
> #if defined(CONFIG_BOARD_EARLY_INIT_R)
> board_early_init_r,
> #endif
>
> ---
> base-commit: 064556910e61044f1295162ceaad600582b66cda
> change-id: 20250218-init-dab1fc72abd2
>
> Best regards,
> --
> J. Neuschäfer <j...@posteo.net>
>
>
The driver model way of doing this would be that your UCLASS_WDT
driver calls uclass_first_device(UCLASS_IRQ) to make sure interrupts
are ready.
The arch_initr_trap thing should probably not be used in new code.
Also, we have interrupt_init() which sounds like it is similar?
Regards,
Simon
