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

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

[Chrispine Tinega]

A K3 remote core can tell Linux it has crashed by sending RP_MBOX_CRASH,
but the K3 drivers only log it. Nothing reaches the remoteproc core, so
the crash is not counted and recovery never runs. The core stays halted
until the next boot, with its rpmsg channels dead.

Patch 1 reports the crash with rproc_report_crash(). This applies to
every K3 remote that uses the common mailbox callback.

Patch 2 leaves recovery enabled on the M4F. Its stop is a plain reset,
so recovery does not need the crashed core to answer. The R5F and DSP
drivers keep recovery disabled. A crashed core there moves to
RPROC_CRASHED, and can be stopped and started again through sysfs.

Tested on an AM625 board (BLIIoT BL350) running TI's 6.12 kernel with
the equivalent change. The M4F runs Zephyr, whose fatal-error handler
sends RP_MBOX_CRASH. After a forced fault, recovery reset and rebooted
the M4F in 71 ms, and Linux kept running. Mainline's M4F stop is the
same plain reset that this test used for a crashed core.

Chrispine Tinega (2):
  remoteproc: k3: Report a remote crash to the remoteproc core
  remoteproc: k3-m4: Leave crash recovery enabled

 drivers/remoteproc/ti_k3_common.c        | 5 +----
 drivers/remoteproc/ti_k3_m4_remoteproc.c | 1 -
 2 files changed, 1 insertion(+), 5 deletions(-)


base-commit: ec1f9ba57b02fe12a6fa5f141206d439ba3d044e
-- 
2.53.0

[PATCH 1/2] remoteproc: k3: Report a remote crash to the remoteproc core

[Chrispine Tinega]

A K3 remote core that faults can send RP_MBOX_CRASH over the mailbox,
but k3_rproc_mbox_callback() only logs it. The remoteproc core never
learns of the crash, so its recovery never runs, the crash is not
counted, and the core stays halted with every rpmsg channel to it dead.

Call rproc_report_crash(), which may be called from atomic context. The
core then moves to RPROC_CRASHED and the crash is counted. Where the
driver leaves recovery enabled, recovery stops the core and boots it
again. Where recovery is disabled, the core can still be stopped and
started again through sysfs.

Signed-off-by: Chrispine Tinega <dev@chrispinetinega.com>
---
 drivers/remoteproc/ti_k3_common.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_common.c b/drivers/remoteproc/ti_k3_common.c
index 4b6da3363..d799f377b 100644
--- a/drivers/remoteproc/ti_k3_common.c
+++ b/drivers/remoteproc/ti_k3_common.c
@@ -60,11 +60,8 @@ void k3_rproc_mbox_callback(struct mbox_client *client, void *data)
 
 	switch (msg) {
 	case RP_MBOX_CRASH:
-		/*
-		 * remoteproc detected an exception, but error recovery is not
-		 * supported. So, just log this for now
-		 */
 		dev_err(dev, "K3 rproc %s crashed\n", rproc->name);
+		rproc_report_crash(rproc, RPROC_FATAL_ERROR);
 		break;
 	case RP_MBOX_ECHO_REPLY:
 		dev_info(dev, "received echo reply from %s\n", rproc->name);
-- 
2.53.0

[PATCH 2/2] remoteproc: k3-m4: Leave crash recovery enabled

[Chrispine Tinega]

The M4 driver disables recovery, but nothing reported a crash to the
remoteproc core, so there was nothing to recover from. Now that
RP_MBOX_CRASH reaches rproc_report_crash(), recovery resets the M4F and
boots its firmware again, while Linux keeps running. The stop is a
plain reset, so it does not need the crashed core's cooperation.

Leave recovery enabled by default. Userspace can still disable it
through /sys/class/remoteproc/remoteprocN/recovery.

Signed-off-by: Chrispine Tinega <dev@chrispinetinega.com>
---
 drivers/remoteproc/ti_k3_m4_remoteproc.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/remoteproc/ti_k3_m4_remoteproc.c b/drivers/remoteproc/ti_k3_m4_remoteproc.c
index 4c46f4a25..fbd2b7c04 100644
--- a/drivers/remoteproc/ti_k3_m4_remoteproc.c
+++ b/drivers/remoteproc/ti_k3_m4_remoteproc.c
@@ -56,7 +56,6 @@ static int k3_m4_rproc_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	rproc->has_iommu = false;
-	rproc->recovery_disabled = true;
 	kproc = rproc->priv;
 	kproc->dev = dev;
 	kproc->rproc = rproc;
-- 
2.53.0