Re: [PATCH] drm/amdgpu: Ensure the DMA engine is deactivated during set ups

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Looks good of hand, but please run your patch through the checkpatch.pl script found in the linux kernel source.

I haven't double checked, but of hand a few lines look a bit long.

Christian.

Am 27.04.22 um 14:09 schrieb ricetons@xxxxxxxxx:
From: Haohui Mai <ricetons@xxxxxxxxx>

The patch fully deactivates the DMA engine before setting up the ring
buffer to avoid potential data races and crashes.

Signed-off-by: Haohui Mai <ricetons@xxxxxxxxx>
---
  drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c | 88 +++++++++++++-------------
  1 file changed, 45 insertions(+), 43 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c b/drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c
index 013d2dec81d0..61d58e515fe7 100644
--- a/drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c
+++ b/drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c
@@ -459,7 +459,6 @@ 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
   *
@@ -505,17 +504,18 @@ 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.
+ * @i: 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 i)
  {
  	u32 f32_cntl, phase_quantum = 0;
-	int i;
+
+	BUG_ON(i >= adev->sdma.num_instances);
if (amdgpu_sdma_phase_quantum) {
  		unsigned value = amdgpu_sdma_phase_quantum;
@@ -539,26 +539,44 @@ 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;
+
+		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);
  	}
- 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, 1);
+		WREG32(sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_CNTL), f32_cntl);
+	}
+}
- 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);
-		}
+/**
+ * sdma_v5_2_ctx_switch_disable_all - stop the async dma engines context switch
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * Halt the async dma engines context switch.
+ */
+static void sdma_v5_2_ctx_switch_disable_all(struct amdgpu_device *adev)
+{
+	u32 f32_cntl;
+	int i;
+	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);
+	}
  }
/**
@@ -571,21 +589,10 @@ static void sdma_v5_2_ctx_switch_enable(struct amdgpu_device *adev, bool enable)
   */
  static void sdma_v5_2_enable(struct amdgpu_device *adev, bool enable)
  {
-	u32 f32_cntl;
-	int i;
-
  	if (!enable) {
  		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);
-			WREG32(sdma_v5_2_get_reg_offset(adev, i, mmSDMA0_F32_CNTL), f32_cntl);
-		}
-	}
  }
/**
@@ -594,6 +601,8 @@ 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)
@@ -737,10 +746,7 @@ 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) {
@@ -856,7 +862,7 @@ 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_ctx_switch_disable_all(adev);
  		sdma_v5_2_enable(adev, false);
/* set RB registers */
@@ -881,12 +887,8 @@ 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);
@@ -1340,7 +1342,7 @@ 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_ctx_switch_disable_all(adev);
  	sdma_v5_2_enable(adev, false);
return 0;




[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux