[PATCH] drm/msm/dpu: ensure device suspend happens during PM sleep

[Kalyan Thota <kalyan_t@xxxxxxxxxxxxxx>]

"The PM core always increments the runtime usage counter
before calling the ->suspend() callback and decrements it
after calling the ->resume() callback"

DPU and DSI are managed as runtime devices. When
suspend is triggered, PM core adds a refcount on all the
devices and calls device suspend, since usage count is
already incremented, runtime suspend was not getting called
and it kept the clocks on which resulted in target not
entering into XO shutdown.

Add changes to manage runtime devices during pm sleep.

Changes in v1:
 - Remove unnecessary checks in the function
   _dpu_kms_disable_dpu (Rob Clark).

Changes in v2:
 - Avoid using suspend_late to reset the usagecount
   as suspend_late might not be called during suspend
   call failures (Doug).

Signed-off-by: Kalyan Thota <kalyan_t@xxxxxxxxxxxxxx>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 33 +++++++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/msm_drv.c           |  4 ++++
 drivers/gpu/drm/msm/msm_kms.h           |  2 ++
 3 files changed, 39 insertions(+)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index ce19f1d..2343cbd 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -26,6 +26,7 @@
 #include "dpu_encoder.h"
 #include "dpu_plane.h"
 #include "dpu_crtc.h"
+#include "dsi.h"
 
 #define CREATE_TRACE_POINTS
 #include "dpu_trace.h"
@@ -325,6 +326,37 @@ static void dpu_kms_disable_commit(struct msm_kms *kms)
 	pm_runtime_put_sync(&dpu_kms->pdev->dev);
 }
 
+static void _dpu_kms_disable_dpu(struct msm_kms *kms)
+{
+	struct dpu_kms *dpu_kms = to_dpu_kms(kms);
+	struct drm_device *dev = dpu_kms->dev;
+	struct msm_drm_private *priv = dev->dev_private;
+	struct msm_dsi *dsi;
+	int i;
+
+	dpu_kms_disable_commit(kms);
+
+	for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
+		if (!priv->dsi[i])
+			continue;
+		dsi = priv->dsi[i];
+		pm_runtime_put_sync(&dsi->pdev->dev);
+	}
+	pm_runtime_put_sync(dev->dev);
+
+	/* Increment the usagecount without triggering a resume */
+	pm_runtime_get_noresume(dev->dev);
+
+	pm_runtime_get_noresume(&dpu_kms->pdev->dev);
+
+	for (i = 0; i < ARRAY_SIZE(priv->dsi); i++) {
+		if (!priv->dsi[i])
+			continue;
+		dsi = priv->dsi[i];
+		pm_runtime_get_noresume(&dsi->pdev->dev);
+	}
+}
+
 static ktime_t dpu_kms_vsync_time(struct msm_kms *kms, struct drm_crtc *crtc)
 {
 	struct drm_encoder *encoder;
@@ -751,6 +783,7 @@ static void dpu_irq_uninstall(struct msm_kms *kms)
 #ifdef CONFIG_DEBUG_FS
 	.debugfs_init    = dpu_kms_debugfs_init,
 #endif
+	.disable_dpu = _dpu_kms_disable_dpu,
 };
 
 static void _dpu_kms_mmu_destroy(struct dpu_kms *dpu_kms)
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 7d985f8..bb11e00 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -1040,6 +1040,7 @@ static int msm_pm_suspend(struct device *dev)
 {
 	struct drm_device *ddev = dev_get_drvdata(dev);
 	struct msm_drm_private *priv = ddev->dev_private;
+	struct msm_kms *kms = priv->kms;
 
 	if (WARN_ON(priv->pm_state))
 		drm_atomic_state_put(priv->pm_state);
@@ -1051,6 +1052,9 @@ static int msm_pm_suspend(struct device *dev)
 		return ret;
 	}
 
+	if (kms->funcs->disable_dpu)
+		kms->funcs->disable_dpu(kms);
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h
index 1cbef6b..c73a89b 100644
--- a/drivers/gpu/drm/msm/msm_kms.h
+++ b/drivers/gpu/drm/msm/msm_kms.h
@@ -126,6 +126,8 @@ struct msm_kms_funcs {
 	/* debugfs: */
 	int (*debugfs_init)(struct msm_kms *kms, struct drm_minor *minor);
 #endif
+	void (*disable_dpu)(struct msm_kms *kms);
+
 };
 
 struct msm_kms;
-- 
1.9.1