[PATCH 2/2] drm/msm/a5xx: Add hangcheck progress detection

[Dmitry Baryshkov]

A5xx has no progress callback, so any submit still running when the
hangcheck timer expires is declared hung, and long compute dispatches
such as KHR-GLES31.core.compute_shader.simple-compute-shared_context are
reset on A530 while still making progress.

Comparing the CP IB1/IB2 state, as a3xx and a6xx do, is not enough: during
a long dispatch the CP has fetched the whole IB and waits in one packet.
Also count ALU working cycles on SP performance counter 0, which Mesa
leaves to the kernel (and the kernel hasn't been using up to now).

Assisted-by: LLM
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 27 +++++++++++++++++++++++++++
 drivers/gpu/drm/msm/adreno/a5xx_gpu.h |  2 ++
 2 files changed, 29 insertions(+)

diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index 5d96b8f63156..9f4a97195cde 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -748,6 +748,9 @@ static int a5xx_hw_init(struct msm_gpu *gpu)
 	/* Select RBBM0 to countable 6 to get the busy status for devfreq */
 	gpu_write(gpu, REG_A5XX_RBBM_PERFCTR_RBBM_SEL_0, 6);
 
+	/* Select SP0 to count ALU cycles for hangcheck progress detection */
+	gpu_write(gpu, REG_A5XX_SP_PERFCTR_SP_SEL_0, PERF_SP_ALU_WORKING_CYCLES);
+
 	/* Increase VFD cache access so LRZ and other data gets evicted less */
 	gpu_write(gpu, REG_A5XX_UCHE_CACHE_WAYS, 0x02);
 
@@ -1687,6 +1690,29 @@ static uint32_t a5xx_get_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
 	return ring->memptrs->rptr = gpu_read(gpu, REG_A5XX_CP_RB_RPTR);
 }
 
+static bool a5xx_progress(struct msm_gpu *gpu, struct msm_ringbuffer *ring)
+{
+	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
+	struct a5xx_gpu *a5xx_gpu = to_a5xx_gpu(adreno_gpu);
+	struct msm_cp_state cp_state = {
+		.ib1_base = gpu_read64(gpu, REG_A5XX_CP_IB1_BASE),
+		.ib2_base = gpu_read64(gpu, REG_A5XX_CP_IB2_BASE),
+		.ib1_rem  = gpu_read(gpu, REG_A5XX_CP_IB1_BUFSZ),
+		.ib2_rem  = gpu_read(gpu, REG_A5XX_CP_IB2_BUFSZ),
+	};
+	u64 alu_cycles = gpu_read64(gpu, REG_A5XX_RBBM_PERFCTR_SP_0_LO);
+	bool progress;
+
+	/* The CP can stall on one packet while shaders keep running */
+	progress = !!memcmp(&cp_state, &ring->last_cp_state, sizeof(cp_state)) ||
+		   alu_cycles != a5xx_gpu->last_alu_cycles;
+
+	ring->last_cp_state = cp_state;
+	a5xx_gpu->last_alu_cycles = alu_cycles;
+
+	return progress;
+}
+
 static void check_speed_bin(struct device *dev)
 {
 	struct nvmem_cell *cell;
@@ -1800,6 +1826,7 @@ const struct adreno_gpu_funcs a5xx_gpu_funcs = {
 		.gpu_state_put = a5xx_gpu_state_put,
 		.create_vm = adreno_create_vm,
 		.get_rptr = a5xx_get_rptr,
+		.progress = a5xx_progress,
 	},
 	.init = a5xx_gpu_init,
 	.get_timestamp = a5xx_get_timestamp,
diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.h b/drivers/gpu/drm/msm/adreno/a5xx_gpu.h
index 407bb950d350..fb05f1ca3e81 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.h
@@ -36,6 +36,8 @@ struct a5xx_gpu {
 	uint64_t preempt_iova[MSM_GPU_MAX_RINGS];
 	uint32_t last_seqno[MSM_GPU_MAX_RINGS];
 
+	uint64_t last_alu_cycles;
+
 	atomic_t preempt_state;
 	spinlock_t preempt_start_lock;
 	struct timer_list preempt_timer;

-- 
2.47.3