drm/msm/a6xx: Switch to GMU AO counter

CP_ALWAYS_ON counter falls under GX domain which is collapsed during
IFPC. So switch to GMU_ALWAYS_ON counter for any CPU reads since it is
not impacted by IFPC. Both counters are clocked by same xo clock source.

Signed-off-by: Akhil P Oommen <akhilpo@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/673373/
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>

Author: akhilpo-qcom

drivers/gpu/drm/msm/adreno/a6xx_gpu.c

@@ -16,6 +16,19 @@
 
 #define GPU_PAS_ID 13
 
+static u64 read_gmu_ao_counter(struct a6xx_gpu *a6xx_gpu)
+{
+	u64 count_hi, count_lo, temp;
+
+	do {
+		count_hi = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_H);
+		count_lo = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_L);
+		temp = gmu_read(&a6xx_gpu->gmu, REG_A6XX_GMU_ALWAYS_ON_COUNTER_H);
+	} while (unlikely(count_hi != temp));
+
+	return (count_hi << 32) | count_lo;
+}
+
 static bool fence_status_check(struct msm_gpu *gpu, u32 offset, u32 value, u32 status, u32 mask)
 {
 	/* Success if !writedropped0/1 */
@@ -376,8 +389,7 @@ static void a6xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 	OUT_RING(ring, upper_32_bits(rbmemptr(ring, fence)));
 	OUT_RING(ring, submit->seqno);
 
-	trace_msm_gpu_submit_flush(submit,
-		gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
+	trace_msm_gpu_submit_flush(submit, read_gmu_ao_counter(a6xx_gpu));
 
 	a6xx_flush(gpu, ring);
 }
@@ -577,8 +589,7 @@ static void a7xx_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
 	}
 
 
-	trace_msm_gpu_submit_flush(submit,
-		gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER));
+	trace_msm_gpu_submit_flush(submit, read_gmu_ao_counter(a6xx_gpu));
 
 	a6xx_flush(gpu, ring);
 
@@ -2268,16 +2279,7 @@ static int a6xx_gmu_get_timestamp(struct msm_gpu *gpu, uint64_t *value)
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
 	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
 
-	mutex_lock(&a6xx_gpu->gmu.lock);
-
-	/* Force the GPU power on so we can read this register */
-	a6xx_gmu_set_oob(&a6xx_gpu->gmu, GMU_OOB_PERFCOUNTER_SET);
-
-	*value = gpu_read64(gpu, REG_A6XX_CP_ALWAYS_ON_COUNTER);
-
-	a6xx_gmu_clear_oob(&a6xx_gpu->gmu, GMU_OOB_PERFCOUNTER_SET);
-
-	mutex_unlock(&a6xx_gpu->gmu.lock);
+	*value = read_gmu_ao_counter(a6xx_gpu);
 
 	return 0;
 }