[Intel-xe] [PATCH v2 26/30] drm/xe/tlb: Obtain forcewake when doing GGTT TLB invalidations

[Matt Roper]

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.

Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi at intel.com>
---
 drivers/gpu/drm/xe/xe_ggtt.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_ggtt.c b/drivers/gpu/drm/xe/xe_ggtt.c
index 31f958613c2f..8f8d0f6a82cd 100644
--- a/drivers/gpu/drm/xe/xe_ggtt.c
+++ b/drivers/gpu/drm/xe/xe_ggtt.c
@@ -193,6 +193,13 @@ 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) {
@@ -214,6 +221,8 @@ 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)
-- 
2.40.0