drm/msm/mdp5: Set up runtime PM for MDSS

MDSS represents the top level wrapper that contains MDP5, DSI, HDMI and
other sub-blocks. W.r.t device heirarchy, it's the parent of all these
devices. The power domain of this device is actually tied to the GDSC
hw. When any sub-device enables its PD, MDSS's PD is also enabled.

The suspend/resume ops enable the top level clocks that end at the MDSS
boundary. For now, we're letting them all be optional, since the child
devices anyway hold a ref to these clocks.

Until now, we'd called a runtime_get() during probe, which ensured that
the GDSC was always on. Now that we've set up runtime PM for the children
devices, we can get rid of this hack.

Note: that the MDSS device is the platform_device in msm_drv.c. The
msm_runtime_suspend/resume ops call the funcs that enable/disable
the top level MDSS clocks. This is different from MDP4, where the
platform device created in msm_drv.c represents MDP4 itself. It would
have been nicer to hide these differences by adding new kms funcs, but
runtime PM needs to be enabled before kms is set up (i.e, msm_kms_init
is called).
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/mdp/mdp5/mdp5_mdss.c

@@ -31,6 +31,10 @@ struct msm_mdss {
 
 	struct regulator *vdd;
 
+	struct clk *ahb_clk;
+	struct clk *axi_clk;
+	struct clk *vsync_clk;
+
 	struct {
 		volatile unsigned long enabled_mask;
 		struct irq_domain *domain;
@@ -140,6 +144,51 @@ static int mdss_irq_domain_init(struct msm_mdss *mdss)
 	return 0;
 }
 
+int msm_mdss_enable(struct msm_mdss *mdss)
+{
+	DBG("");
+
+	clk_prepare_enable(mdss->ahb_clk);
+	if (mdss->axi_clk)
+		clk_prepare_enable(mdss->axi_clk);
+	if (mdss->vsync_clk)
+		clk_prepare_enable(mdss->vsync_clk);
+
+	return 0;
+}
+
+int msm_mdss_disable(struct msm_mdss *mdss)
+{
+	DBG("");
+
+	if (mdss->vsync_clk)
+		clk_disable_unprepare(mdss->vsync_clk);
+	if (mdss->axi_clk)
+		clk_disable_unprepare(mdss->axi_clk);
+	clk_disable_unprepare(mdss->ahb_clk);
+
+	return 0;
+}
+
+static int msm_mdss_get_clocks(struct msm_mdss *mdss)
+{
+	struct platform_device *pdev = to_platform_device(mdss->dev->dev);
+
+	mdss->ahb_clk = msm_clk_get(pdev, "iface");
+	if (IS_ERR(mdss->ahb_clk))
+		mdss->ahb_clk = NULL;
+
+	mdss->axi_clk = msm_clk_get(pdev, "bus");
+	if (IS_ERR(mdss->axi_clk))
+		mdss->axi_clk = NULL;
+
+	mdss->vsync_clk = msm_clk_get(pdev, "vsync");
+	if (IS_ERR(mdss->vsync_clk))
+		mdss->vsync_clk = NULL;
+
+	return 0;
+}
+
 void msm_mdss_destroy(struct drm_device *dev)
 {
 	struct msm_drm_private *priv = dev->dev_private;
@@ -153,8 +202,6 @@ void msm_mdss_destroy(struct drm_device *dev)
 
 	regulator_disable(mdss->vdd);
 
-	pm_runtime_put_sync(dev->dev);
-
 	pm_runtime_disable(dev->dev);
 }
 
@@ -190,6 +237,12 @@ int msm_mdss_init(struct drm_device *dev)
 		goto fail;
 	}
 
+	ret = msm_mdss_get_clocks(mdss);
+	if (ret) {
+		dev_err(dev->dev, "failed to get clocks: %d\n", ret);
+		goto fail;
+	}
+
 	/* Regulator to enable GDSCs in downstream kernels */
 	mdss->vdd = devm_regulator_get(dev->dev, "vdd");
 	if (IS_ERR(mdss->vdd)) {
@@ -221,12 +274,6 @@ int msm_mdss_init(struct drm_device *dev)
 
 	pm_runtime_enable(dev->dev);
 
-	/*
-	 * TODO: This is needed as the MDSS GDSC is only tied to MDSS's power
-	 * domain. Remove this once runtime PM is adapted for all the devices.
-	 */
-	pm_runtime_get_sync(dev->dev);
-
 	return 0;
 fail_irq:
 	regulator_disable(mdss->vdd);

drivers/gpu/drm/msm/msm_drv.c

@@ -879,8 +879,37 @@ static int msm_pm_resume(struct device *dev)
 }
 #endif
 
+#ifdef CONFIG_PM
+static int msm_runtime_suspend(struct device *dev)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct msm_drm_private *priv = ddev->dev_private;
+
+	DBG("");
+
+	if (priv->mdss)
+		return msm_mdss_disable(priv->mdss);
+
+	return 0;
+}
+
+static int msm_runtime_resume(struct device *dev)
+{
+	struct drm_device *ddev = dev_get_drvdata(dev);
+	struct msm_drm_private *priv = ddev->dev_private;
+
+	DBG("");
+
+	if (priv->mdss)
+		return msm_mdss_enable(priv->mdss);
+
+	return 0;
+}
+#endif
+
 static const struct dev_pm_ops msm_pm_ops = {
 	SET_SYSTEM_SLEEP_PM_OPS(msm_pm_suspend, msm_pm_resume)
+	SET_RUNTIME_PM_OPS(msm_runtime_suspend, msm_runtime_resume, NULL)
 };
 
 /*

drivers/gpu/drm/msm/msm_kms.h

@@ -99,5 +99,7 @@ struct msm_kms *mdp4_kms_init(struct drm_device *dev);
 struct msm_kms *mdp5_kms_init(struct drm_device *dev);
 int msm_mdss_init(struct drm_device *dev);
 void msm_mdss_destroy(struct drm_device *dev);
+int msm_mdss_enable(struct msm_mdss *mdss);
+int msm_mdss_disable(struct msm_mdss *mdss);
 
 #endif /* __MSM_KMS_H__ */