drm/i915/gt: Pull ring submission resume under its caller forcewake

Take advantage of calling xcs_resume under a forcewake by using direct
mmio access. In particular, we can avoid the sleeping variants to allow
resume to be called from softirq context, required for engine resets.

v2: Keep the posting read at the start of resume as a guardian memory
barrier.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210119110802.22228-5-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_ring_submission.c

@@ -122,31 +122,27 @@ static void set_hwsp(struct intel_engine_cs *engine, u32 offset)
 		hwsp = RING_HWS_PGA(engine->mmio_base);
 	}
 
-	intel_uncore_write(engine->uncore, hwsp, offset);
-	intel_uncore_posting_read(engine->uncore, hwsp);
+	intel_uncore_write_fw(engine->uncore, hwsp, offset);
+	intel_uncore_posting_read_fw(engine->uncore, hwsp);
 }
 
 static void flush_cs_tlb(struct intel_engine_cs *engine)
 {
-	struct drm_i915_private *dev_priv = engine->i915;
-
-	if (!IS_GEN_RANGE(dev_priv, 6, 7))
+	if (!IS_GEN_RANGE(engine->i915, 6, 7))
 		return;
 
 	/* ring should be idle before issuing a sync flush*/
-	drm_WARN_ON(&dev_priv->drm,
-		    (ENGINE_READ(engine, RING_MI_MODE) & MODE_IDLE) == 0);
-
-	ENGINE_WRITE(engine, RING_INSTPM,
-		     _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
-					INSTPM_SYNC_FLUSH));
-	if (intel_wait_for_register(engine->uncore,
-				    RING_INSTPM(engine->mmio_base),
-				    INSTPM_SYNC_FLUSH, 0,
-				    1000))
-		drm_err(&dev_priv->drm,
-			"%s: wait for SyncFlush to complete for TLB invalidation timed out\n",
-			engine->name);
+	GEM_DEBUG_WARN_ON((ENGINE_READ(engine, RING_MI_MODE) & MODE_IDLE) == 0);
+
+	ENGINE_WRITE_FW(engine, RING_INSTPM,
+			_MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
+					   INSTPM_SYNC_FLUSH));
+	if (__intel_wait_for_register_fw(engine->uncore,
+					 RING_INSTPM(engine->mmio_base),
+					 INSTPM_SYNC_FLUSH, 0,
+					 2000, 0, NULL))
+		ENGINE_TRACE(engine,
+			     "wait for SyncFlush to complete for TLB invalidation timed out\n");
 }
 
 static void ring_setup_status_page(struct intel_engine_cs *engine)
@@ -177,13 +173,13 @@ static void set_pp_dir(struct intel_engine_cs *engine)
 	if (!vm)
 		return;
 
-	ENGINE_WRITE(engine, RING_PP_DIR_DCLV, PP_DIR_DCLV_2G);
-	ENGINE_WRITE(engine, RING_PP_DIR_BASE, pp_dir(vm));
+	ENGINE_WRITE_FW(engine, RING_PP_DIR_DCLV, PP_DIR_DCLV_2G);
+	ENGINE_WRITE_FW(engine, RING_PP_DIR_BASE, pp_dir(vm));
 
 	if (INTEL_GEN(engine->i915) >= 7) {
-		ENGINE_WRITE(engine,
-			     RING_MODE_GEN7,
-			     _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
+		ENGINE_WRITE_FW(engine,
+				RING_MODE_GEN7,
+				_MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
 	}
 }
 
@@ -191,13 +187,10 @@ static int xcs_resume(struct intel_engine_cs *engine)
 {
 	struct drm_i915_private *dev_priv = engine->i915;
 	struct intel_ring *ring = engine->legacy.ring;
-	int ret = 0;
 
 	ENGINE_TRACE(engine, "ring:{HEAD:%04x, TAIL:%04x}\n",
 		     ring->head, ring->tail);
 
-	intel_uncore_forcewake_get(engine->uncore, FORCEWAKE_ALL);
-
 	if (HWS_NEEDS_PHYSICAL(dev_priv))
 		ring_setup_phys_status_page(engine);
 	else
@@ -214,7 +207,7 @@ static int xcs_resume(struct intel_engine_cs *engine)
 	 * also enforces ordering), otherwise the hw might lose the new ring
 	 * register values.
 	 */
-	ENGINE_WRITE(engine, RING_START, i915_ggtt_offset(ring->vma));
+	ENGINE_WRITE_FW(engine, RING_START, i915_ggtt_offset(ring->vma));
 
 	/* Check that the ring offsets point within the ring! */
 	GEM_BUG_ON(!intel_ring_offset_valid(ring, ring->head));
@@ -224,46 +217,44 @@ static int xcs_resume(struct intel_engine_cs *engine)
 	set_pp_dir(engine);
 
 	/* First wake the ring up to an empty/idle ring */
-	ENGINE_WRITE(engine, RING_HEAD, ring->head);
-	ENGINE_WRITE(engine, RING_TAIL, ring->head);
+	ENGINE_WRITE_FW(engine, RING_HEAD, ring->head);
+	ENGINE_WRITE_FW(engine, RING_TAIL, ring->head);
 	ENGINE_POSTING_READ(engine, RING_TAIL);
 
-	ENGINE_WRITE(engine, RING_CTL, RING_CTL_SIZE(ring->size) | RING_VALID);
+	ENGINE_WRITE_FW(engine, RING_CTL,
+			RING_CTL_SIZE(ring->size) | RING_VALID);
 
 	/* If the head is still not zero, the ring is dead */
-	if (intel_wait_for_register(engine->uncore,
-				    RING_CTL(engine->mmio_base),
-				    RING_VALID, RING_VALID,
-				    50)) {
-		drm_err(&dev_priv->drm, "%s initialization failed "
-			  "ctl %08x (valid? %d) head %08x [%08x] tail %08x [%08x] start %08x [expected %08x]\n",
-			  engine->name,
-			  ENGINE_READ(engine, RING_CTL),
-			  ENGINE_READ(engine, RING_CTL) & RING_VALID,
-			  ENGINE_READ(engine, RING_HEAD), ring->head,
-			  ENGINE_READ(engine, RING_TAIL), ring->tail,
-			  ENGINE_READ(engine, RING_START),
-			  i915_ggtt_offset(ring->vma));
-		ret = -EIO;
-		goto out;
+	if (__intel_wait_for_register_fw(engine->uncore,
+					 RING_CTL(engine->mmio_base),
+					 RING_VALID, RING_VALID,
+					 5000, 0, NULL)) {
+		drm_err(&dev_priv->drm,
+			"%s initialization failed; "
+			"ctl %08x (valid? %d) head %08x [%08x] tail %08x [%08x] start %08x [expected %08x]\n",
+			engine->name,
+			ENGINE_READ(engine, RING_CTL),
+			ENGINE_READ(engine, RING_CTL) & RING_VALID,
+			ENGINE_READ(engine, RING_HEAD), ring->head,
+			ENGINE_READ(engine, RING_TAIL), ring->tail,
+			ENGINE_READ(engine, RING_START),
+			i915_ggtt_offset(ring->vma));
+		return -EIO;
 	}
 
 	if (INTEL_GEN(dev_priv) > 2)
-		ENGINE_WRITE(engine,
-			     RING_MI_MODE, _MASKED_BIT_DISABLE(STOP_RING));
+		ENGINE_WRITE_FW(engine,
+				RING_MI_MODE, _MASKED_BIT_DISABLE(STOP_RING));
 
 	/* Now awake, let it get started */
 	if (ring->tail != ring->head) {
-		ENGINE_WRITE(engine, RING_TAIL, ring->tail);
+		ENGINE_WRITE_FW(engine, RING_TAIL, ring->tail);
 		ENGINE_POSTING_READ(engine, RING_TAIL);
 	}
 
 	/* Papering over lost _interrupts_ immediately following the restart */
 	intel_engine_signal_breadcrumbs(engine);
-out:
-	intel_uncore_forcewake_put(engine->uncore, FORCEWAKE_ALL);
-
-	return ret;
+	return 0;
 }
 
 static void sanitize_hwsp(struct intel_engine_cs *engine)