[PATCH v4 0/3] re-factor devfreq common code

[PATCH v4 0/3] re-factor devfreq common code

[Sharat Masetty]

This series re-factors the devfreq code a bit in preparation for the upcoming
A6x related devfreq changes. The code applies cleanly on 4.17 and has been
verified on DB820C.

V2: Addressed code review comments from Jordan Crouse.
V3: Added a new patch for devfreq cleanup.
V4: removed "drm/msm: move suspend/resume devfreq to their own functions"(for
now)

Sharat Masetty (3):
  drm/msm: suspend devfreq on init
  drm/msm: re-factor devfreq code
  drm/msm: unregister devfreq upon clean up

 drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 16 ++++++++++++----
 drivers/gpu/drm/msm/msm_gpu.c         | 27 ++++++++++++++++++---------
 drivers/gpu/drm/msm/msm_gpu.h         |  4 +++-
 3 files changed, 33 insertions(+), 14 deletions(-)

--
1.9.1

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[PATCH v4 1/3] drm/msm: suspend devfreq on init

[Sharat Masetty]

Devfreq turns on and starts recommending power level as soon as it is
initialized. The GPU is still not powered on by the time the devfreq
init happens and this leads to problems on GPU's where register access
is needed to get/set power levels. So we start suspended and only restart
devfreq when GPU is powered on.

Signed-off-by: Sharat Masetty <smasetty@codeaurora.org>
---
 drivers/gpu/drm/msm/msm_gpu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index 1c09acf..d7586f2 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -104,6 +104,8 @@ static void msm_devfreq_init(struct msm_gpu *gpu)
 		dev_err(&gpu->pdev->dev, "Couldn't initialize GPU devfreq\n");
 		gpu->devfreq.devfreq = NULL;
 	}
+
+	devfreq_suspend_device(gpu->devfreq.devfreq);
 }
 
 static int enable_pwrrail(struct msm_gpu *gpu)
-- 
1.9.1

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[PATCH v4 2/3] 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@codeaurora.org>
---
 drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 16 ++++++++++++----
 drivers/gpu/drm/msm/msm_gpu.c         | 23 ++++++++++++++---------
 drivers/gpu/drm/msm/msm_gpu.h         |  4 +++-
 3 files changed, 29 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..5cdf104 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -1219,12 +1219,20 @@ 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 unsigned long 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;
+	unsigned long 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 d7586f2..ffa5b77 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, *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 b824117..4863e4e 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);
+	unsigned long (*gpu_busy)(struct msm_gpu *gpu);
+	unsigned long (*gpu_get_freq)(struct msm_gpu *gpu);
+	int (*gpu_set_freq)(struct msm_gpu *gpu, unsigned long freq);
 };
 
 struct msm_gpu {
-- 
1.9.1

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[PATCH v4 3/3] drm/msm: unregister devfreq upon clean up

[Sharat Masetty]

Call the devfreq_remove_device() API to remove the GPU devfreq instance
during GPU driver cleanup.

Signed-off-by: Sharat Masetty <smasetty@codeaurora.org>
---
 drivers/gpu/drm/msm/msm_gpu.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
index ffa5b77..c9d5fdf 100644
--- a/drivers/gpu/drm/msm/msm_gpu.c
+++ b/drivers/gpu/drm/msm/msm_gpu.c
@@ -889,6 +889,8 @@ void msm_gpu_cleanup(struct msm_gpu *gpu)
 
 	WARN_ON(!list_empty(&gpu->active_list));
 
+	devfreq_remove_device(gpu->devfreq.devfreq);
+
 	for (i = 0; i < ARRAY_SIZE(gpu->rb); i++) {
 		msm_ringbuffer_destroy(gpu->rb[i]);
 		gpu->rb[i] = NULL;
-- 
1.9.1

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Re: [PATCH v4 0/3] re-factor devfreq common code

[Jordan Crouse]

On Fri, Jun 08, 2018 at 11:56:04AM +0530, Sharat Masetty wrote:
> This series re-factors the devfreq code a bit in preparation for the upcoming
> A6x related devfreq changes. The code applies cleanly on 4.17 and has been
> verified on DB820C.
> 
> V2: Addressed code review comments from Jordan Crouse.
> V3: Added a new patch for devfreq cleanup.
> V4: removed "drm/msm: move suspend/resume devfreq to their own functions"(for
> now)
> 
> Sharat Masetty (3):
>   drm/msm: suspend devfreq on init
>   drm/msm: re-factor devfreq code
>   drm/msm: unregister devfreq upon clean up
> 
>  drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 16 ++++++++++++----
>  drivers/gpu/drm/msm/msm_gpu.c         | 27 ++++++++++++++++++---------
>  drivers/gpu/drm/msm/msm_gpu.h         |  4 +++-
>  3 files changed, 33 insertions(+), 14 deletions(-)

Rob, it would be great to get these queued for 4.19 since they make life better
for the eventual a6xx changes.

Thanks,
Jordan

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a Linux Foundation Collaborative Project
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