[PATCH 3/3] drm/msm: re-factor devfreq code

[Sharat Masetty]

devfreq framework requires the drivers to provide busy time estimations.
The GPU driver relies on the hardware performance counters for the busy time
estimations, but different hardware revisions have counters which can be
sourced from different clocks. So the busy time estimation will be target
dependent.  Additionally on targets where the clocks are completely controlled
by the on chip microcontroller, fetching and setting the current GPU frequency
will be different. This patch aims to embrace these differences by re-factoring
the devfreq code a bit.

Signed-off-by: Sharat Masetty <smasetty at codeaurora.org>
---
 drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 15 +++++++++++----
 drivers/gpu/drm/msm/msm_gpu.c         | 23 ++++++++++++++---------
 drivers/gpu/drm/msm/msm_gpu.h         |  4 +++-
 3 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index d39400e..a35a840 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -1219,12 +1219,19 @@ static struct msm_ringbuffer *a5xx_active_ring(struct msm_gpu *gpu)
 	return a5xx_gpu->cur_ring;
 }
 
-static int a5xx_gpu_busy(struct msm_gpu *gpu, uint64_t *value)
+static u64 a5xx_gpu_busy(struct msm_gpu *gpu)
 {
-	*value = gpu_read64(gpu, REG_A5XX_RBBM_PERFCTR_RBBM_0_LO,
-		REG_A5XX_RBBM_PERFCTR_RBBM_0_HI);
+	u64 busy_cycles, busy_time;
 
-	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) /
+		(clk_get_rate(gpu->core_clk) / 1000000);
+
+	gpu->devfreq.busy_cycles = busy_cycles;
+
+	return busy_time;
 }
 
 static const struct adreno_gpu_funcs funcs = {
diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index d8d4fc9..f437ee8 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -40,7 +40,11 @@ static int msm_devfreq_target(struct device *dev, unsigned long *freq,
 	if (IS_ERR(opp))
 		return PTR_ERR(opp);
 
-	clk_set_rate(gpu->core_clk, *freq);
+	if (gpu->funcs->gpu_set_freq)
+		gpu->funcs->gpu_set_freq(gpu, (u64)*freq);
+	else
+		clk_set_rate(gpu->core_clk, *freq);
+
 	dev_pm_opp_put(opp);
 
 	return 0;
@@ -50,16 +54,14 @@ static int msm_devfreq_get_dev_status(struct device *dev,
 		struct devfreq_dev_status *status)
 {
 	struct msm_gpu *gpu = platform_get_drvdata(to_platform_device(dev));
-	u64 cycles;
-	u32 freq = ((u32) status->current_frequency) / 1000000;
 	ktime_t time;
 
-	status->current_frequency = (unsigned long) clk_get_rate(gpu->core_clk);
-	gpu->funcs->gpu_busy(gpu, &cycles);
-
-	status->busy_time = ((u32) (cycles - gpu->devfreq.busy_cycles)) / freq;
+	if (gpu->funcs->gpu_get_freq)
+		status->current_frequency = gpu->funcs->gpu_get_freq(gpu);
+	else
+		status->current_frequency = clk_get_rate(gpu->core_clk);
 
-	gpu->devfreq.busy_cycles = cycles;
+	status->busy_time = gpu->funcs->gpu_busy(gpu);
 
 	time = ktime_get();
 	status->total_time = ktime_us_delta(time, gpu->devfreq.time);
@@ -72,7 +74,10 @@ static int msm_devfreq_get_cur_freq(struct device *dev, unsigned long *freq)
 {
 	struct msm_gpu *gpu = platform_get_drvdata(to_platform_device(dev));
 
-	*freq = (unsigned long) clk_get_rate(gpu->core_clk);
+	if (gpu->funcs->gpu_get_freq)
+		*freq = gpu->funcs->gpu_get_freq(gpu);
+	else
+		*freq = clk_get_rate(gpu->core_clk);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 1876b81..d3f02e7 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -68,7 +68,9 @@ struct msm_gpu_funcs {
 	/* for generation specific debugfs: */
 	int (*debugfs_init)(struct msm_gpu *gpu, struct drm_minor *minor);
 #endif
-	int (*gpu_busy)(struct msm_gpu *gpu, uint64_t *value);
+	u64 (*gpu_busy)(struct msm_gpu *gpu);
+	u64 (*gpu_get_freq)(struct msm_gpu *gpu);
+	int (*gpu_set_freq)(struct msm_gpu *gpu, u64 freq);
 };
 
 struct msm_gpu {
-- 
1.9.1