[PATCH 1/4] drm/panthor: Force an immediate reset on unrecoverable faults

[Steven Price]

On 02/05/2024 19:38, Boris Brezillon wrote:
> If the FW reports an unrecoverable fault, we need to reset the GPU
> before we can start re-using it again.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>

Reviewed-by: Steven Price <steven.price at arm.com>

> ---
>  drivers/gpu/drm/panthor/panthor_device.c |  1 +
>  drivers/gpu/drm/panthor/panthor_device.h |  1 +
>  drivers/gpu/drm/panthor/panthor_sched.c  | 11 ++++++++++-
>  3 files changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
> index 75276cbeba20..4c5b54e7abb7 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.c
> +++ b/drivers/gpu/drm/panthor/panthor_device.c
> @@ -293,6 +293,7 @@ static const struct panthor_exception_info panthor_exception_infos[] = {
>  	PANTHOR_EXCEPTION(ACTIVE),
>  	PANTHOR_EXCEPTION(CS_RES_TERM),
>  	PANTHOR_EXCEPTION(CS_CONFIG_FAULT),
> +	PANTHOR_EXCEPTION(CS_UNRECOVERABLE),
>  	PANTHOR_EXCEPTION(CS_ENDPOINT_FAULT),
>  	PANTHOR_EXCEPTION(CS_BUS_FAULT),
>  	PANTHOR_EXCEPTION(CS_INSTR_INVALID),
> diff --git a/drivers/gpu/drm/panthor/panthor_device.h b/drivers/gpu/drm/panthor/panthor_device.h
> index 2fdd671b38fd..e388c0472ba7 100644
> --- a/drivers/gpu/drm/panthor/panthor_device.h
> +++ b/drivers/gpu/drm/panthor/panthor_device.h
> @@ -216,6 +216,7 @@ enum drm_panthor_exception_type {
>  	DRM_PANTHOR_EXCEPTION_CS_RES_TERM = 0x0f,
>  	DRM_PANTHOR_EXCEPTION_MAX_NON_FAULT = 0x3f,
>  	DRM_PANTHOR_EXCEPTION_CS_CONFIG_FAULT = 0x40,
> +	DRM_PANTHOR_EXCEPTION_CS_UNRECOVERABLE = 0x41,
>  	DRM_PANTHOR_EXCEPTION_CS_ENDPOINT_FAULT = 0x44,
>  	DRM_PANTHOR_EXCEPTION_CS_BUS_FAULT = 0x48,
>  	DRM_PANTHOR_EXCEPTION_CS_INSTR_INVALID = 0x49,
> diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c
> index 7f16a4a14e9a..1d2708c3ab0a 100644
> --- a/drivers/gpu/drm/panthor/panthor_sched.c
> +++ b/drivers/gpu/drm/panthor/panthor_sched.c
> @@ -1281,7 +1281,16 @@ cs_slot_process_fatal_event_locked(struct panthor_device *ptdev,
>  	if (group)
>  		group->fatal_queues |= BIT(cs_id);
>  
> -	sched_queue_delayed_work(sched, tick, 0);
> +	if (CS_EXCEPTION_TYPE(fatal) == DRM_PANTHOR_EXCEPTION_CS_UNRECOVERABLE) {
> +		/* If this exception is unrecoverable, queue a reset, and make
> +		 * sure we stop scheduling groups until the reset has happened.
> +		 */
> +		panthor_device_schedule_reset(ptdev);
> +		cancel_delayed_work(&sched->tick_work);
> +	} else {
> +		sched_queue_delayed_work(sched, tick, 0);
> +	}
> +
>  	drm_warn(&ptdev->base,
>  		 "CSG slot %d CS slot: %d\n"
>  		 "CS_FATAL.EXCEPTION_TYPE: 0x%x (%s)\n"