drm/panthor: Fix the FW reset logic

In the post_reset function, if the fast reset didn't succeed, we
are not clearing the fast_reset flag, which prevents firmware
sections from being reloaded. While at it, use panthor_fw_stop()
instead of manually writing DISABLE to the MCU_CONTROL register.

Fixes: 2718d91816ee ("drm/panthor: Add the FW logical block")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240430113727.493155-1-boris.brezillon@collabora.com

diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
index 181395e2859a9612b7a131ebd200dfd766cf9fb8..fedf9627453fb16ef2397e5db617dfa96f9661d4 100644 (file)
--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -1083,10 +1083,11 @@ int panthor_fw_post_reset(struct panthor_device *ptdev)
                if (!ret)
                        goto out;
 
-               /* Force a disable, so we get a fresh boot on the next
-                * panthor_fw_start() call.
+               /* Forcibly reset the MCU and force a slow reset, so we get a
+                * fresh boot on the next panthor_fw_start() call.
                 */
-               gpu_write(ptdev, MCU_CONTROL, MCU_CONTROL_DISABLE);
+               panthor_fw_stop(ptdev);
+               ptdev->fw->fast_reset = false;
                drm_err(&ptdev->base, "FW fast reset failed, trying a slow reset");
        }