[PATCH 6/6] drm/msm/a6xx: Limit GXPD votes to recovery in A8x

[Taniya Das]

From: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxxxx>

In A8x GPUs, the GX GDSC is moved to a separate block called GXCLKCTL
which is under the GX power domain. Due to the way the support for this
block is implemented in its driver, pm_runtime votes result in a vote on
GX/GMxC/MxC rails from the APPS RSC. This is against the Adreno
architecture which require GMU to be the sole voter of these collapsible
rails on behalf of GPU, except during the GPU/GMU recovery.

To align with this architectural requirement and to realize the power
benefits of the IFPC feature, remove the GXPD votes during gmu resume
and suspend. And during the recovery sequence, enable/disable the GXPD
along with the 'synced_poweroff' genpd hint to force collapse this GDSC.

Signed-off-by: Akhil P Oommen <akhilpo@xxxxxxxxxxxxxxxx>
Signed-off-by: Taniya Das <taniya.das@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/adreno/a6xx_gmu.c | 64 +++++++++++++++++++++++++++++------
 1 file changed, 54 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
index 1b44b9e21ad868e6454b9140284cc7ebedc4f59a..b7166a883b018f459caae742e9a589f32167f8d2 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gmu.c
@@ -1250,6 +1250,56 @@ static int a6xx_gmu_secure_init(struct a6xx_gpu *a6xx_gpu)
 	return 0;
 }
 
+static int a6xx_gmu_gxpd_get(struct a6xx_gmu *gmu)
+{
+	struct a6xx_gpu *a6xx_gpu = container_of(gmu, struct a6xx_gpu, gmu);
+	struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+
+	if (IS_ERR_OR_NULL(gmu->gxpd))
+		return 0;
+
+	/*
+	 * On A8xx HW, GX GDSC is moved to a new clk controller block under GX
+	 * power domain. The clock driver for this new block keeps the GX rail
+	 * voted when gxpd is voted. So, use the gxpd only during gpu recovery.
+	 */
+	if (adreno_gpu->info->family >= ADRENO_8XX_GEN1)
+		return 0;
+
+	/*
+	 * On A6x/A7x, "enable" the GX power domain which won't actually do
+	 * anything but it will make sure that the refcounting is correct in
+	 * case we need to bring down the GX after a GMU failure
+	 */
+	return pm_runtime_get_sync(gmu->gxpd);
+}
+
+static int a6xx_gmu_gxpd_put(struct a6xx_gmu *gmu)
+{
+	struct a6xx_gpu *a6xx_gpu = container_of(gmu, struct a6xx_gpu, gmu);
+	struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+
+	if (IS_ERR_OR_NULL(gmu->gxpd))
+		return 0;
+
+	if (adreno_gpu->info->family < ADRENO_8XX_GEN1)
+		return pm_runtime_put_sync(gmu->gxpd);
+
+	/*
+	 * On A8x, GX GDSC collapse should be triggered only when it is stuck ON
+	 */
+	if (adreno_gpu->funcs->gx_is_on(adreno_gpu)) {
+		pm_runtime_get_sync(gmu->gxpd);
+		/*
+		 * Hint to gfxclkctl driver to do a hw collapse during the next
+		 * RPM PUT. This is a special behavior in the gfxclkctl driver
+		 */
+		dev_pm_genpd_synced_poweroff(gmu->gxpd);
+		pm_runtime_put_sync(gmu->gxpd);
+	}
+
+	return 0;
+}
 
 int a6xx_gmu_resume(struct a6xx_gpu *a6xx_gpu)
 {
@@ -1266,13 +1316,7 @@ int a6xx_gmu_resume(struct a6xx_gpu *a6xx_gpu)
 	/* Turn on the resources */
 	pm_runtime_get_sync(gmu->dev);
 
-	/*
-	 * "enable" the GX power domain which won't actually do anything but it
-	 * will make sure that the refcounting is correct in case we need to
-	 * bring down the GX after a GMU failure
-	 */
-	if (!IS_ERR_OR_NULL(gmu->gxpd))
-		pm_runtime_get_sync(gmu->gxpd);
+	a6xx_gmu_gxpd_get(gmu);
 
 	/* Use a known rate to bring up the GMU */
 	clk_set_rate(gmu->core_clk, 200000000);
@@ -1339,7 +1383,8 @@ int a6xx_gmu_resume(struct a6xx_gpu *a6xx_gpu)
 disable_clk:
 	clk_bulk_disable_unprepare(gmu->nr_clocks, gmu->clocks);
 rpm_put:
-	pm_runtime_put(gmu->gxpd);
+	a6xx_gmu_gxpd_put(gmu);
+
 	pm_runtime_put(gmu->dev);
 
 	return ret;
@@ -1455,8 +1500,7 @@ int a6xx_gmu_stop(struct a6xx_gpu *a6xx_gpu)
 	 * domain. Usually the GMU does this but only if the shutdown sequence
 	 * was successful
 	 */
-	if (!IS_ERR_OR_NULL(gmu->gxpd))
-		pm_runtime_put_sync(gmu->gxpd);
+	a6xx_gmu_gxpd_put(gmu);
 
 	clk_bulk_disable_unprepare(gmu->nr_clocks, gmu->clocks);
 

-- 
2.34.1