drm/amdgpu: Ensure the DMA engine is deactivated during set ups

Setting the HALT bit of SDMA_F32_CNTL in all paths before programming
the ring buffer of the SDMA engine.
Signed-off-by: Haohui Mai <ricetons@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c

@@ -469,7 +469,6 @@ static void sdma_v5_2_ring_emit_fence(struct amdgpu_ring *ring, u64 addr, u64 se
 	}
 }
 
-
 /**
  * sdma_v5_2_gfx_stop - stop the gfx async dma engines
  *
@@ -515,17 +514,21 @@ static void sdma_v5_2_rlc_stop(struct amdgpu_device *adev)
 }
 
 /**
- * sdma_v5_2_ctx_switch_enable - stop the async dma engines context switch
+ * sdma_v5_2_ctx_switch_enable_for_instance - start the async dma engines
+ * context switch for an instance
  *
  * @adev: amdgpu_device pointer
- * @enable: enable/disable the DMA MEs context switch.
+ * @instance_idx: the index of the SDMA instance
  *
- * Halt or unhalt the async dma engines context switch.
+ * Unhalt the async dma engines context switch.
  */
-static void sdma_v5_2_ctx_switch_enable(struct amdgpu_device *adev, bool enable)
+static void sdma_v5_2_ctx_switch_enable_for_instance(struct amdgpu_device *adev, int instance_idx)
 {
 	u32 f32_cntl, phase_quantum = 0;
-	int i;
+
+	if (WARN_ON(instance_idx >= adev->sdma.num_instances)) {
+		return;
+	}
 
 	if (amdgpu_sdma_phase_quantum) {
 		unsigned value = amdgpu_sdma_phase_quantum;
@@ -549,50 +552,68 @@ static void sdma_v5_2_ctx_switch_enable(struct amdgpu_device *adev, bool enable)
 		phase_quantum =
 			value << SDMA0_PHASE0_QUANTUM__VALUE__SHIFT |
 			unit  << SDMA0_PHASE0_QUANTUM__UNIT__SHIFT;
-	}
-
-	for (i = 0; i < adev->sdma.num_instances; i++) {
-		if (enable && amdgpu_sdma_phase_quantum) {
-			WREG32_SOC15_IP(GC, sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_PHASE0_QUANTUM),
-			       phase_quantum);
-			WREG32_SOC15_IP(GC, sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_PHASE1_QUANTUM),
-			       phase_quantum);
-			WREG32_SOC15_IP(GC, sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_PHASE2_QUANTUM),
-			       phase_quantum);
-		}
 
-		if (!amdgpu_sriov_vf(adev)) {
-			f32_cntl = RREG32(sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_CNTL));
-			f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_CNTL,
-					AUTO_CTXSW_ENABLE, enable ? 1 : 0);
-			WREG32(sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_CNTL), f32_cntl);
-		}
+		WREG32_SOC15_IP(GC,
+			sdma_v5_2_get_reg_offset(adev, instance_idx, mmSDMA0_PHASE0_QUANTUM),
+			phase_quantum);
+		WREG32_SOC15_IP(GC,
+			sdma_v5_2_get_reg_offset(adev, instance_idx, mmSDMA0_PHASE1_QUANTUM),
+		    phase_quantum);
+		WREG32_SOC15_IP(GC,
+			sdma_v5_2_get_reg_offset(adev, instance_idx, mmSDMA0_PHASE2_QUANTUM),
+		    phase_quantum);
 	}
 
+	if (!amdgpu_sriov_vf(adev)) {
+		f32_cntl = RREG32(sdma_v5_2_get_reg_offset(adev, instance_idx, mmSDMA0_CNTL));
+		f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_CNTL,
+				AUTO_CTXSW_ENABLE, 1);
+		WREG32(sdma_v5_2_get_reg_offset(adev, instance_idx, mmSDMA0_CNTL), f32_cntl);
+	}
 }
 
 /**
- * sdma_v5_2_enable - stop the async dma engines
+ * sdma_v5_2_ctx_switch_disable_all - stop the async dma engines context switch
  *
  * @adev: amdgpu_device pointer
- * @enable: enable/disable the DMA MEs.
  *
- * Halt or unhalt the async dma engines.
+ * Halt the async dma engines context switch.
  */
-static void sdma_v5_2_enable(struct amdgpu_device *adev, bool enable)
+static void sdma_v5_2_ctx_switch_disable_all(struct amdgpu_device *adev)
 {
 	u32 f32_cntl;
 	int i;
 
-	if (!enable) {
-		sdma_v5_2_gfx_stop(adev);
-		sdma_v5_2_rlc_stop(adev);
+	if (amdgpu_sriov_vf(adev))
+		return;
+
+	for (i = 0; i < adev->sdma.num_instances; i++) {
+		f32_cntl = RREG32(sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_CNTL));
+		f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_CNTL,
+				AUTO_CTXSW_ENABLE, 0);
+		WREG32(sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_CNTL), f32_cntl);
 	}
+}
+
+/**
+ * sdma_v5_2_halt - stop the async dma engines
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * Halt the async dma engines.
+ */
+static void sdma_v5_2_halt(struct amdgpu_device *adev)
+{
+	int i;
+	u32 f32_cntl;
+
+	sdma_v5_2_gfx_stop(adev);
+	sdma_v5_2_rlc_stop(adev);
 
 	if (!amdgpu_sriov_vf(adev)) {
 		for (i = 0; i < adev->sdma.num_instances; i++) {
 			f32_cntl = RREG32(sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_F32_CNTL));
-			f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_F32_CNTL, HALT, enable ? 0 : 1);
+			f32_cntl = REG_SET_FIELD(f32_cntl, SDMA0_F32_CNTL, HALT, 1);
 			WREG32(sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_F32_CNTL), f32_cntl);
 		}
 	}
@@ -604,6 +625,9 @@ static void sdma_v5_2_enable(struct amdgpu_device *adev, bool enable)
  * @adev: amdgpu_device pointer
  *
  * Set up the gfx DMA ring buffers and enable them.
+ * It assumes that the dma engine is stopped for each instance.
+ * The function enables the engine and preemptions sequentially for each instance.
+ *
  * Returns 0 for success, error for failure.
  */
 static int sdma_v5_2_gfx_resume(struct amdgpu_device *adev)
@@ -745,10 +769,7 @@ static int sdma_v5_2_gfx_resume(struct amdgpu_device *adev)
 
 		ring->sched.ready = true;
 
-		if (amdgpu_sriov_vf(adev)) { /* bare-metal sequence doesn't need below to lines */
-			sdma_v5_2_ctx_switch_enable(adev, true);
-			sdma_v5_2_enable(adev, true);
-		}
+		sdma_v5_2_ctx_switch_enable_for_instance(adev, i);
 
 		r = amdgpu_ring_test_ring(ring);
 		if (r) {
@@ -792,7 +813,7 @@ static int sdma_v5_2_load_microcode(struct amdgpu_device *adev)
 	int i, j;
 
 	/* halt the MEs */
-	sdma_v5_2_enable(adev, false);
+	sdma_v5_2_halt(adev);
 
 	for (i = 0; i < adev->sdma.num_instances; i++) {
 		if (!adev->sdma.instance[i].fw)
@@ -864,8 +885,8 @@ static int sdma_v5_2_start(struct amdgpu_device *adev)
 	int r = 0;
 
 	if (amdgpu_sriov_vf(adev)) {
-		sdma_v5_2_ctx_switch_enable(adev, false);
-		sdma_v5_2_enable(adev, false);
+		sdma_v5_2_ctx_switch_disable_all(adev);
+		sdma_v5_2_halt(adev);
 
 		/* set RB registers */
 		r = sdma_v5_2_gfx_resume(adev);
@@ -889,12 +910,10 @@ static int sdma_v5_2_start(struct amdgpu_device *adev)
 		amdgpu_gfx_off_ctrl(adev, false);
 
 	sdma_v5_2_soft_reset(adev);
-	/* unhalt the MEs */
-	sdma_v5_2_enable(adev, true);
-	/* enable sdma ring preemption */
-	sdma_v5_2_ctx_switch_enable(adev, true);
 
-	/* start the gfx rings and rlc compute queues */
+	/* Soft reset supposes to disable the dma engine and preemption.
+	 * Now start the gfx rings and rlc compute queues.
+	 */
 	r = sdma_v5_2_gfx_resume(adev);
 	if (adev->in_s0ix)
 		amdgpu_gfx_off_ctrl(adev, true);
@@ -1428,8 +1447,8 @@ static int sdma_v5_2_hw_fini(void *handle)
 	if (amdgpu_sriov_vf(adev))
 		return 0;
 
-	sdma_v5_2_ctx_switch_enable(adev, false);
-	sdma_v5_2_enable(adev, false);
+	sdma_v5_2_ctx_switch_disable_all(adev);
+	sdma_v5_2_halt(adev);
 
 	return 0;
 }