drm/msm: simplify gpu_busy callback

Move tracking and busy time calculation to msm_devfreq_get_dev_status.

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
Cc: Rob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20220416003314.59211-2-olvaffe@gmail.com
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/adreno/a5xx_gpu.c

@@ -1662,28 +1662,23 @@ static struct msm_ringbuffer *a5xx_active_ring(struct msm_gpu *gpu)
 	return a5xx_gpu->cur_ring;
 }
 
-static unsigned long a5xx_gpu_busy(struct msm_gpu *gpu)
+static u64 a5xx_gpu_busy(struct msm_gpu *gpu, unsigned long *out_sample_rate)
 {
-	u64 busy_cycles, busy_time;
+	u64 busy_cycles;
 
 	/* Only read the gpu busy if the hardware is already active */
-	if (pm_runtime_get_if_in_use(&gpu->pdev->dev) == 0)
+	if (pm_runtime_get_if_in_use(&gpu->pdev->dev) == 0) {
+		*out_sample_rate = 1;
 		return 0;
+	}
 
 	busy_cycles = gpu_read64(gpu, REG_A5XX_RBBM_PERFCTR_RBBM_0_LO,
 			REG_A5XX_RBBM_PERFCTR_RBBM_0_HI);
-
-	busy_time = busy_cycles - gpu->devfreq.busy_cycles;
-	do_div(busy_time, clk_get_rate(gpu->core_clk) / 1000000);
-
-	gpu->devfreq.busy_cycles = busy_cycles;
+	*out_sample_rate = clk_get_rate(gpu->core_clk);
 
 	pm_runtime_put(&gpu->pdev->dev);
 
-	if (WARN_ON(busy_time > ~0LU))
-		return ~0LU;
-
-	return (unsigned long)busy_time;
+	return busy_cycles;
 }
 
 static uint32_t a5xx_get_rptr(struct msm_gpu *gpu, struct msm_ringbuffer *ring)

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

@@ -1649,12 +1649,14 @@ static void a6xx_destroy(struct msm_gpu *gpu)
 	kfree(a6xx_gpu);
 }
 
-static unsigned long a6xx_gpu_busy(struct msm_gpu *gpu)
+static u64 a6xx_gpu_busy(struct msm_gpu *gpu, unsigned long *out_sample_rate)
 {
 	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
 	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
-	u64 busy_cycles, busy_time;
+	u64 busy_cycles;
 
+	/* 19.2MHz */
+	*out_sample_rate = 19200000;
 
 	/* Only read the gpu busy if the hardware is already active */
 	if (pm_runtime_get_if_in_use(a6xx_gpu->gmu.dev) == 0)
@@ -1664,17 +1666,10 @@ static unsigned long a6xx_gpu_busy(struct msm_gpu *gpu)
 			REG_A6XX_GMU_CX_GMU_POWER_COUNTER_XOCLK_0_L,
 			REG_A6XX_GMU_CX_GMU_POWER_COUNTER_XOCLK_0_H);
 
-	busy_time = (busy_cycles - gpu->devfreq.busy_cycles) * 10;
-	do_div(busy_time, 192);
-
-	gpu->devfreq.busy_cycles = busy_cycles;
 
 	pm_runtime_put(a6xx_gpu->gmu.dev);
 
-	if (WARN_ON(busy_time > ~0LU))
-		return ~0LU;
-
-	return (unsigned long)busy_time;
+	return busy_cycles;
 }
 
 static void a6xx_gpu_set_freq(struct msm_gpu *gpu, struct dev_pm_opp *opp)

drivers/gpu/drm/msm/msm_gpu.h

@@ -63,7 +63,7 @@ struct msm_gpu_funcs {
 	/* for generation specific debugfs: */
 	void (*debugfs_init)(struct msm_gpu *gpu, struct drm_minor *minor);
 #endif
-	unsigned long (*gpu_busy)(struct msm_gpu *gpu);
+	u64 (*gpu_busy)(struct msm_gpu *gpu, unsigned long *out_sample_rate);
 	struct msm_gpu_state *(*gpu_state_get)(struct msm_gpu *gpu);
 	int (*gpu_state_put)(struct msm_gpu_state *state);
 	unsigned long (*gpu_get_freq)(struct msm_gpu *gpu);
@@ -107,11 +107,8 @@ struct msm_gpu_devfreq {
 	struct dev_pm_qos_request boost_freq;
 
 	/**
-	 * busy_cycles:
-	 *
-	 * Used by implementation of gpu->gpu_busy() to track the last
-	 * busy counter value, for calculating elapsed busy cycles since
-	 * last sampling period.
+	 * busy_cycles: Last busy counter value, for calculating elapsed busy
+	 * cycles since last sampling period.
 	 */
 	u64 busy_cycles;
 

drivers/gpu/drm/msm/msm_gpu_devfreq.c

@@ -49,18 +49,38 @@ static unsigned long get_freq(struct msm_gpu *gpu)
 	return clk_get_rate(gpu->core_clk);
 }
 
-static int msm_devfreq_get_dev_status(struct device *dev,
+static void get_raw_dev_status(struct msm_gpu *gpu,
 		struct devfreq_dev_status *status)
 {
-	struct msm_gpu *gpu = dev_to_gpu(dev);
+	struct msm_gpu_devfreq *df = &gpu->devfreq;
+	u64 busy_cycles, busy_time;
+	unsigned long sample_rate;
 	ktime_t time;
 
 	status->current_frequency = get_freq(gpu);
-	status->busy_time = gpu->funcs->gpu_busy(gpu);
-
+	busy_cycles = gpu->funcs->gpu_busy(gpu, &sample_rate);
 	time = ktime_get();
-	status->total_time = ktime_us_delta(time, gpu->devfreq.time);
-	gpu->devfreq.time = time;
+
+	busy_time = busy_cycles - df->busy_cycles;
+	status->total_time = ktime_us_delta(time, df->time);
+
+	df->busy_cycles = busy_cycles;
+	df->time = time;
+
+	busy_time *= USEC_PER_SEC;
+	do_div(busy_time, sample_rate);
+	if (WARN_ON(busy_time > ~0LU))
+		busy_time = ~0LU;
+
+	status->busy_time = busy_time;
+}
+
+static int msm_devfreq_get_dev_status(struct device *dev,
+		struct devfreq_dev_status *status)
+{
+	struct msm_gpu *gpu = dev_to_gpu(dev);
+
+	get_raw_dev_status(gpu, status);
 
 	return 0;
 }