[PATCH v6] drm/amdgpu: Ensure the DMA engine is deactivated during set ups
Haohui Mai
ricetons at gmail.com
Wed May 4 22:48:10 UTC 2022
Ping...
________________________________
From: ricetons at gmail.com <ricetons at gmail.com>
Sent: Saturday, April 30, 2022 3:34:00 PM
To: amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>
Cc: lang.yu at amd.com <lang.yu at amd.com>; ckoenig.leichtzumerken at gmail.com <ckoenig.leichtzumerken at gmail.com>; Guchun.Chen at amd.com <Guchun.Chen at amd.com>; yifan1.zhang at amd.com <yifan1.zhang at amd.com>; Hawking.Zhang at amd.com <Hawking.Zhang at amd.com>; Haohui Mai <ricetons at gmail.com>
Subject: [PATCH v6] drm/amdgpu: Ensure the DMA engine is deactivated during set ups
From: Haohui Mai <ricetons at gmail.com>
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 at gmail.com>
---
drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c | 109 +++++++++++++++----------
1 file changed, 64 insertions(+), 45 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..1fac9d8e99de 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 +504,21 @@ 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;
@@ -539,50 +542,68 @@ 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);
}
}
@@ -594,6 +615,9 @@ 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)
@@ -737,10 +761,7 @@ 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) {
@@ -784,7 +805,7 @@ 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)
@@ -856,8 +877,8 @@ 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);
@@ -881,12 +902,10 @@ 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);
@@ -1340,8 +1359,8 @@ 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;
}
--
2.25.1
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