drm/xe/tlb: Obtain forcewake when doing GGTT TLB invalidations

Updates to the GGTT can happen when there are no in-flight jobs keeping
the hardware awake.  If the GT is powered down when invalidation is
requested, we will not be able to communicate with the GuC (or MMIO) and
the invalidation request will go missing.  Explicitly grab GT forcewake
to ensure the GT and GuC are powered up during the TLB invalidation.
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>
Link: https://lore.kernel.org/r/20230601215244.678611-28-matthew.d.roper@intel.comSigned-off-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/xe/xe_ggtt.c

@@ -195,6 +195,13 @@ static void ggtt_invalidate_gt_tlb(struct xe_gt *gt)
 	if (!gt)
 		return;
 
+	/*
+	 * Invalidation can happen when there's no in-flight work keeping the
+	 * GT awake.  We need to explicitly grab forcewake to ensure the GT
+	 * and GuC are accessible.
+	 */
+	xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
+
 	/* TODO: vfunc for GuC vs. non-GuC */
 
 	if (gt->uc.guc.submission_state.enabled) {
@@ -216,6 +223,8 @@ static void ggtt_invalidate_gt_tlb(struct xe_gt *gt)
 			xe_mmio_write32(gt, GUC_TLB_INV_CR,
 					GUC_TLB_INV_CR_INVALIDATE);
 	}
+
+	xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
 }
 
 void xe_ggtt_invalidate(struct xe_ggtt *ggtt)