Re: [PATCH 0/2] remoteproc: k3: Recover a crashed remote core

[Francesco Valla <francesco@valla.it>]

Hi Chrispine,

On Mon, Nov 09, 2026 at 07:04:30PM +0300, Chrispine Tinega wrote:
> Hi Francesco,
> 
> On Mon, 9 Nov 2026, Francesco Valla wrote:
> > If you share details on the Zephyr side of things, I can test this
> > against rproc-next on a AM67A (BeagleY-AI).
> 
> Thank you, that would help. The AM67A has no M4F, so patch 2 does not
> apply there. Patch 1 does: the R5F driver uses the same mailbox
> callback, and it keeps recovery disabled. So on the main R5F I would
> expect this:
> 
> - Without the series, the crash is only logged, and the core stays in
>   "running" until the next boot.
> - With the series, the core moves to "crashed", the crash is counted,
>   and it can be stopped and started again through sysfs.
> 
> The Zephyr side is upstream's openamp_rsc_table sample with one file
> added. The handler sends RP_MBOX_CRASH over the mailbox before it
> halts, and a thread forces a fault 20 s after boot. This builds on
> Zephyr v4.5.0 for beagley_ai/j722s/main_r5f0_0, but I have not run it
> on that board.

I did run it on the "MCU" R5F, and I think I found a bug... in the Zephyr
ti_dmtimer code! With that fixed, the functionality seems to be working
as expected, but I'll stress it a bit before declaring a Tested-by.

> 
> Copy samples/subsys/ipc/openamp_rsc_table, add src/crash.c below, and
> list it in CMakeLists.txt:
> 
>   target_sources(app PRIVATE src/main_remote.c src/crash.c)
> 
> Build it:
> 
>   west build -b beagley_ai/j722s/main_r5f0_0 path/to/the/copy
> 
> Load build/zephyr/zephyr_openamp_rsc_table.elf as the main R5F's
> firmware. After 20 s, check the state:
> 
>   cat /sys/class/remoteproc/remoteprocN/state
>   dmesg | grep -i crash
> 
> To bring the core back:
> 
>   echo stop > /sys/class/remoteproc/remoteprocN/state
>   echo start > /sys/class/remoteproc/remoteprocN/state
> 
> It will crash again 20 s after each start. That is a quick way to check
> that a second crash is handled as well.
> 
> --- src/crash.c ---
> /*
>  * Report a fatal error to Linux as RP_MBOX_CRASH, then force one.
>  */
> #include <zephyr/kernel.h>
> #include <zephyr/drivers/ipm.h>
> #include <zephyr/fatal.h>
> #include <zephyr/logging/log_ctrl.h>
> 
> #define RP_MBOX_CRASH 0xFFFFFF02U
> #define CRASH_AFTER_S 20
> 
> static const struct device *const crash_ipm =
> 	DEVICE_DT_GET(DT_CHOSEN(zephyr_ipc));
> 
> void k_sys_fatal_error_handler(unsigned int reason,
> 			       const struct arch_esf *esf)
> {
> 	uint32_t crash = RP_MBOX_CRASH;
> 
> 	ARG_UNUSED(reason);
> 	ARG_UNUSED(esf);
> 
> 	LOG_PANIC();
> 	/* The FIFO can be briefly full of vring kicks. */
> 	for (int i = 0; i < 100; i++) {
> 		if (ipm_send(crash_ipm, 0, 0, &crash, sizeof(crash)) != -EBUSY)
> 			break;
> 		k_busy_wait(100);
> 	}
> 	(void)arch_irq_lock();
> 	for (;;)
> 		arch_cpu_idle();
> }
> 
> static void crash_thread(void *a, void *b, void *c)
> {
> 	k_sleep(K_SECONDS(CRASH_AFTER_S));
> 	k_oops();
> }
> 
> K_THREAD_DEFINE(crash_tid, 1024, crash_thread, NULL, NULL, NULL,
> 		K_PRIO_PREEMPT(10), 0, 0);
> --- end ---
> 
> Regards,
> Chrispine
> 

Regards,
Francesco