drm/i915: Do not attempt to load the GSC multiple times

If the GSC FW fails to load the GSC HW hangs permanently; the only ways
to recover it are FLR or D3cold entry, with the former only being
supported on driver unload and the latter only on DGFX, for which we
don't need to load the GSC. Therefore, if GSC fails to load there is no
need to try again because the HW is stuck in the error state and the
submission to load the FW would just hang the GSCCS.

Note that, due to wa_14015076503, on MTL the GuC escalates all GSCCS
hangs to full GT resets, which would trigger a new attempt to load the
GSC FW in the post-reset HW re-init; this issue is also fixed by not
attempting to load the GSC FW after an error.

Fixes: 15bd4a67 ("drm/i915/gsc: GSC firmware loading")
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: <stable@vger.kernel.org> # v6.3+
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240820215952.2290807-1-daniele.ceraolospurio@intel.com

drivers/gpu/drm/i915/gt/uc/intel_gsc_uc.c

@@ -302,7 +302,7 @@ void intel_gsc_uc_load_start(struct intel_gsc_uc *gsc)
 {
 	struct intel_gt *gt = gsc_uc_to_gt(gsc);
 
-	if (!intel_uc_fw_is_loadable(&gsc->fw))
+	if (!intel_uc_fw_is_loadable(&gsc->fw) || intel_uc_fw_is_in_error(&gsc->fw))
 		return;
 
 	if (intel_gsc_uc_fw_init_done(gsc))

drivers/gpu/drm/i915/gt/uc/intel_uc_fw.h

@@ -258,6 +258,11 @@ static inline bool intel_uc_fw_is_running(struct intel_uc_fw *uc_fw)
 	return __intel_uc_fw_status(uc_fw) == INTEL_UC_FIRMWARE_RUNNING;
 }
 
+static inline bool intel_uc_fw_is_in_error(struct intel_uc_fw *uc_fw)
+{
+	return intel_uc_fw_status_to_error(__intel_uc_fw_status(uc_fw)) != 0;
+}
+
 static inline bool intel_uc_fw_is_overridden(const struct intel_uc_fw *uc_fw)
 {
 	return uc_fw->user_overridden;