drm/tegra: Do not implement runtime PM

The Tegra DRM driver heavily relies on the implementations for runtime
suspend/resume to be called at specific times. Unfortunately, there are
some cases where that doesn't work. One example is if the user disables
runtime PM for a given subdevice. Another example is that the PM core
acquires a reference to runtime PM during system sleep, effectively
preventing devices from going into low power modes. This is intentional
to avoid nasty race conditions, but it also causes system sleep to not
function properly on all Tegra systems.

Fix this by not implementing runtime PM at all. Instead, a minimal,
reference-counted suspend/resume infrastructure is added to the host1x
bus. This has the benefit that it can be used regardless of the system
power state (or any transitions we might be in), or whether or not the
user allows runtime PM.

Atomic modesetting guarantees that these functions will end up being
called at the right point in time, so the pitfalls for the more generic
runtime PM do not apply here.

Signed-off-by: Thierry Reding <[e-mail]>

drivers/gpu/drm/tegra/dc.c

···
 {
 	struct tegra_dc *dc = to_tegra_dc(crtc);
 	u32 value;
+	int err;
 
 	if (!tegra_dc_idle(dc)) {
 		tegra_dc_stop(dc);
···
 
 	spin_unlock_irq(&crtc->dev->event_lock);
 
-	pm_runtime_put_sync(dc->dev);
+	err = host1x_client_suspend(&dc->client);
+	if (err < 0)
+		dev_err(dc->dev, "failed to suspend: %d\n", err);
 }
 
 static void tegra_crtc_atomic_enable(struct drm_crtc *crtc,
···
 	struct tegra_dc_state *state = to_dc_state(crtc->state);
 	struct tegra_dc *dc = to_tegra_dc(crtc);
 	u32 value;
+	int err;
 
-	pm_runtime_get_sync(dc->dev);
+	err = host1x_client_resume(&dc->client);
+	if (err < 0) {
+		dev_err(dc->dev, "failed to resume: %d\n", err);
+		return;
+	}
 
 	/* initialize display controller */
 	if (dc->syncpt) {
···
 	if (!tegra_dc_has_window_groups(dc))
 		return 0;
 
+	/*
+	 * Set the display hub as the host1x client parent for the display
+	 * controller. This is needed for the runtime reference counting that
+	 * ensures the display hub is always powered when any of the display
+	 * controllers are.
+	 */
+	if (dc->soc->has_nvdisplay)
+		client->parent = &tegra->hub->client;
+
 	dc->syncpt = host1x_syncpt_request(client, flags);
 	if (!dc->syncpt)
 		dev_warn(dc->dev, "failed to allocate syncpoint\n");
···
 	return 0;
 }
 
+static int tegra_dc_runtime_suspend(struct host1x_client *client)
+{
+	struct tegra_dc *dc = host1x_client_to_dc(client);
+	struct device *dev = client->dev;
+	int err;
+
+	err = reset_control_assert(dc->rst);
+	if (err < 0) {
+		dev_err(dev, "failed to assert reset: %d\n", err);
+		return err;
+	}
+
+	if (dc->soc->has_powergate)
+		tegra_powergate_power_off(dc->powergate);
+
+	clk_disable_unprepare(dc->clk);
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static int tegra_dc_runtime_resume(struct host1x_client *client)
+{
+	struct tegra_dc *dc = host1x_client_to_dc(client);
+	struct device *dev = client->dev;
+	int err;
+
+	err = pm_runtime_get_sync(dev);
+	if (err < 0) {
+		dev_err(dev, "failed to get runtime PM: %d\n", err);
+		return err;
+	}
+
+	if (dc->soc->has_powergate) {
+		err = tegra_powergate_sequence_power_up(dc->powergate, dc->clk,
+							dc->rst);
+		if (err < 0) {
+			dev_err(dev, "failed to power partition: %d\n", err);
+			goto put_rpm;
+		}
+	} else {
+		err = clk_prepare_enable(dc->clk);
+		if (err < 0) {
+			dev_err(dev, "failed to enable clock: %d\n", err);
+			goto put_rpm;
+		}
+
+		err = reset_control_deassert(dc->rst);
+		if (err < 0) {
+			dev_err(dev, "failed to deassert reset: %d\n", err);
+			goto disable_clk;
+		}
+	}
+
+	return 0;
+
+disable_clk:
+	clk_disable_unprepare(dc->clk);
+put_rpm:
+	pm_runtime_put_sync(dev);
+	return err;
+}
+
 static const struct host1x_client_ops dc_client_ops = {
 	.init = tegra_dc_init,
 	.exit = tegra_dc_exit,
+	.suspend = tegra_dc_runtime_suspend,
+	.resume = tegra_dc_runtime_resume,
 };
 
 static const struct tegra_dc_soc_info tegra20_dc_soc_info = {
···
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int tegra_dc_suspend(struct device *dev)
-{
-	struct tegra_dc *dc = dev_get_drvdata(dev);
-	int err;
-
-	err = reset_control_assert(dc->rst);
-	if (err < 0) {
-		dev_err(dev, "failed to assert reset: %d\n", err);
-		return err;
-	}
-
-	if (dc->soc->has_powergate)
-		tegra_powergate_power_off(dc->powergate);
-
-	clk_disable_unprepare(dc->clk);
-
-	return 0;
-}
-
-static int tegra_dc_resume(struct device *dev)
-{
-	struct tegra_dc *dc = dev_get_drvdata(dev);
-	int err;
-
-	if (dc->soc->has_powergate) {
-		err = tegra_powergate_sequence_power_up(dc->powergate, dc->clk,
-							dc->rst);
-		if (err < 0) {
-			dev_err(dev, "failed to power partition: %d\n", err);
-			return err;
-		}
-	} else {
-		err = clk_prepare_enable(dc->clk);
-		if (err < 0) {
-			dev_err(dev, "failed to enable clock: %d\n", err);
-			return err;
-		}
-
-		err = reset_control_deassert(dc->rst);
-		if (err < 0) {
-			dev_err(dev, "failed to deassert reset: %d\n", err);
-			return err;
-		}
-	}
-
-	return 0;
-}
-#endif
-
-static const struct dev_pm_ops tegra_dc_pm_ops = {
-	SET_RUNTIME_PM_OPS(tegra_dc_suspend, tegra_dc_resume, NULL)
-};
-
 struct platform_driver tegra_dc_driver = {
 	.driver = {
 		.name = "tegra-dc",
 		.of_match_table = tegra_dc_of_match,
-		.pm = &tegra_dc_pm_ops,
 	},
 	.probe = tegra_dc_probe,
 	.remove = tegra_dc_remove,

drivers/gpu/drm/tegra/dpaux.c

···
 	/* make sure pads are powered down when not in use */
 	tegra_dpaux_pad_power_down(dpaux);
 
-	pm_runtime_put(&pdev->dev);
+	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
 	drm_dp_aux_unregister(&dpaux->aux);

drivers/gpu/drm/tegra/drm.h

···
 void tegra_output_exit(struct tegra_output *output);
 void tegra_output_find_possible_crtcs(struct tegra_output *output,
 				      struct drm_device *drm);
+int tegra_output_suspend(struct tegra_output *output);
+int tegra_output_resume(struct tegra_output *output);
 
 int tegra_output_connector_get_modes(struct drm_connector *connector);
 enum drm_connector_status

drivers/gpu/drm/tegra/dsi.c

···
 		dev_err(dsi->dev, "failed to disable MIPI calibration: %d\n",
 			err);
 
-	pm_runtime_put(dsi->dev);
+	err = host1x_client_suspend(&dsi->client);
+	if (err < 0)
+		dev_err(dsi->dev, "failed to suspend: %d\n", err);
 }
 
 static void tegra_dsi_encoder_disable(struct drm_encoder *encoder)
···
 	tegra_dsi_unprepare(dsi);
 }
 
-static void tegra_dsi_prepare(struct tegra_dsi *dsi)
+static int tegra_dsi_prepare(struct tegra_dsi *dsi)
 {
 	int err;
 
-	pm_runtime_get_sync(dsi->dev);
+	err = host1x_client_resume(&dsi->client);
+	if (err < 0) {
+		dev_err(dsi->dev, "failed to resume: %d\n", err);
+		return err;
+	}
 
 	err = tegra_mipi_enable(dsi->mipi);
 	if (err < 0)
···
 
 	if (dsi->slave)
 		tegra_dsi_prepare(dsi->slave);
+
+	return 0;
 }
 
 static void tegra_dsi_encoder_enable(struct drm_encoder *encoder)
···
 	struct tegra_dsi *dsi = to_dsi(output);
 	struct tegra_dsi_state *state;
 	u32 value;
+	int err;
 
-	tegra_dsi_prepare(dsi);
+	err = tegra_dsi_prepare(dsi);
+	if (err < 0) {
+		dev_err(dsi->dev, "failed to prepare: %d\n", err);
+		return;
+	}
 
 	state = tegra_dsi_get_state(dsi);
 
···
 	return 0;
 }
 
+static int tegra_dsi_runtime_suspend(struct host1x_client *client)
+{
+	struct tegra_dsi *dsi = host1x_client_to_dsi(client);
+	struct device *dev = client->dev;
+	int err;
+
+	if (dsi->rst) {
+		err = reset_control_assert(dsi->rst);
+		if (err < 0) {
+			dev_err(dev, "failed to assert reset: %d\n", err);
+			return err;
+		}
+	}
+
+	usleep_range(1000, 2000);
+
+	clk_disable_unprepare(dsi->clk_lp);
+	clk_disable_unprepare(dsi->clk);
+
+	regulator_disable(dsi->vdd);
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static int tegra_dsi_runtime_resume(struct host1x_client *client)
+{
+	struct tegra_dsi *dsi = host1x_client_to_dsi(client);
+	struct device *dev = client->dev;
+	int err;
+
+	err = pm_runtime_get_sync(dev);
+	if (err < 0) {
+		dev_err(dev, "failed to get runtime PM: %d\n", err);
+		return err;
+	}
+
+	err = regulator_enable(dsi->vdd);
+	if (err < 0) {
+		dev_err(dev, "failed to enable VDD supply: %d\n", err);
+		goto put_rpm;
+	}
+
+	err = clk_prepare_enable(dsi->clk);
+	if (err < 0) {
+		dev_err(dev, "cannot enable DSI clock: %d\n", err);
+		goto disable_vdd;
+	}
+
+	err = clk_prepare_enable(dsi->clk_lp);
+	if (err < 0) {
+		dev_err(dev, "cannot enable low-power clock: %d\n", err);
+		goto disable_clk;
+	}
+
+	usleep_range(1000, 2000);
+
+	if (dsi->rst) {
+		err = reset_control_deassert(dsi->rst);
+		if (err < 0) {
+			dev_err(dev, "cannot assert reset: %d\n", err);
+			goto disable_clk_lp;
+		}
+	}
+
+	return 0;
+
+disable_clk_lp:
+	clk_disable_unprepare(dsi->clk_lp);
+disable_clk:
+	clk_disable_unprepare(dsi->clk);
+disable_vdd:
+	regulator_disable(dsi->vdd);
+put_rpm:
+	pm_runtime_put_sync(dev);
+	return err;
+}
+
 static const struct host1x_client_ops dsi_client_ops = {
 	.init = tegra_dsi_init,
 	.exit = tegra_dsi_exit,
+	.suspend = tegra_dsi_runtime_suspend,
+	.resume = tegra_dsi_runtime_resume,
 };
 
 static int tegra_dsi_setup_clocks(struct tegra_dsi *dsi)
···
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int tegra_dsi_suspend(struct device *dev)
-{
-	struct tegra_dsi *dsi = dev_get_drvdata(dev);
-	int err;
-
-	if (dsi->rst) {
-		err = reset_control_assert(dsi->rst);
-		if (err < 0) {
-			dev_err(dev, "failed to assert reset: %d\n", err);
-			return err;
-		}
-	}
-
-	usleep_range(1000, 2000);
-
-	clk_disable_unprepare(dsi->clk_lp);
-	clk_disable_unprepare(dsi->clk);
-
-	regulator_disable(dsi->vdd);
-
-	return 0;
-}
-
-static int tegra_dsi_resume(struct device *dev)
-{
-	struct tegra_dsi *dsi = dev_get_drvdata(dev);
-	int err;
-
-	err = regulator_enable(dsi->vdd);
-	if (err < 0) {
-		dev_err(dsi->dev, "failed to enable VDD supply: %d\n", err);
-		return err;
-	}
-
-	err = clk_prepare_enable(dsi->clk);
-	if (err < 0) {
-		dev_err(dev, "cannot enable DSI clock: %d\n", err);
-		goto disable_vdd;
-	}
-
-	err = clk_prepare_enable(dsi->clk_lp);
-	if (err < 0) {
-		dev_err(dev, "cannot enable low-power clock: %d\n", err);
-		goto disable_clk;
-	}
-
-	usleep_range(1000, 2000);
-
-	if (dsi->rst) {
-		err = reset_control_deassert(dsi->rst);
-		if (err < 0) {
-			dev_err(dev, "cannot assert reset: %d\n", err);
-			goto disable_clk_lp;
-		}
-	}
-
-	return 0;
-
-disable_clk_lp:
-	clk_disable_unprepare(dsi->clk_lp);
-disable_clk:
-	clk_disable_unprepare(dsi->clk);
-disable_vdd:
-	regulator_disable(dsi->vdd);
-	return err;
-}
-#endif
-
-static const struct dev_pm_ops tegra_dsi_pm_ops = {
-	SET_RUNTIME_PM_OPS(tegra_dsi_suspend, tegra_dsi_resume, NULL)
-};
-
 static const struct of_device_id tegra_dsi_of_match[] = {
 	{ .compatible = "nvidia,tegra210-dsi", },
 	{ .compatible = "nvidia,tegra132-dsi", },
···
 	.driver = {
 		.name = "tegra-dsi",
 		.of_match_table = tegra_dsi_of_match,
-		.pm = &tegra_dsi_pm_ops,
 	},
 	.probe = tegra_dsi_probe,
 	.remove = tegra_dsi_remove,

drivers/gpu/drm/tegra/hdmi.c

···
 	struct tegra_dc *dc = to_tegra_dc(encoder->crtc);
 	struct tegra_hdmi *hdmi = to_hdmi(output);
 	u32 value;
+	int err;
 
 	/*
 	 * The following accesses registers of the display controller, so make
···
 	tegra_hdmi_writel(hdmi, 0, HDMI_NV_PDISP_INT_ENABLE);
 	tegra_hdmi_writel(hdmi, 0, HDMI_NV_PDISP_INT_MASK);
 
-	pm_runtime_put(hdmi->dev);
+	err = host1x_client_suspend(&hdmi->client);
+	if (err < 0)
+		dev_err(hdmi->dev, "failed to suspend: %d\n", err);
 }
 
 static void tegra_hdmi_encoder_enable(struct drm_encoder *encoder)
···
 	u32 value;
 	int err;
 
-	pm_runtime_get_sync(hdmi->dev);
+	err = host1x_client_resume(&hdmi->client);
+	if (err < 0) {
+		dev_err(hdmi->dev, "failed to resume: %d\n", err);
+		return;
+	}
 
 	/*
 	 * Enable and unmask the HDA codec SCRATCH0 register interrupt. This
···
 	return 0;
 }
 
+static int tegra_hdmi_runtime_suspend(struct host1x_client *client)
+{
+	struct tegra_hdmi *hdmi = host1x_client_to_hdmi(client);
+	struct device *dev = client->dev;
+	int err;
+
+	err = reset_control_assert(hdmi->rst);
+	if (err < 0) {
+		dev_err(dev, "failed to assert reset: %d\n", err);
+		return err;
+	}
+
+	usleep_range(1000, 2000);
+
+	clk_disable_unprepare(hdmi->clk);
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static int tegra_hdmi_runtime_resume(struct host1x_client *client)
+{
+	struct tegra_hdmi *hdmi = host1x_client_to_hdmi(client);
+	struct device *dev = client->dev;
+	int err;
+
+	err = pm_runtime_get_sync(dev);
+	if (err < 0) {
+		dev_err(dev, "failed to get runtime PM: %d\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(hdmi->clk);
+	if (err < 0) {
+		dev_err(dev, "failed to enable clock: %d\n", err);
+		goto put_rpm;
+	}
+
+	usleep_range(1000, 2000);
+
+	err = reset_control_deassert(hdmi->rst);
+	if (err < 0) {
+		dev_err(dev, "failed to deassert reset: %d\n", err);
+		goto disable_clk;
+	}
+
+	return 0;
+
+disable_clk:
+	clk_disable_unprepare(hdmi->clk);
+put_rpm:
+	pm_runtime_put_sync(dev);
+	return err;
+}
+
 static const struct host1x_client_ops hdmi_client_ops = {
 	.init = tegra_hdmi_init,
 	.exit = tegra_hdmi_exit,
+	.suspend = tegra_hdmi_runtime_suspend,
+	.resume = tegra_hdmi_runtime_resume,
 };
 
 static const struct tegra_hdmi_config tegra20_hdmi_config = {
···
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int tegra_hdmi_suspend(struct device *dev)
-{
-	struct tegra_hdmi *hdmi = dev_get_drvdata(dev);
-	int err;
-
-	err = reset_control_assert(hdmi->rst);
-	if (err < 0) {
-		dev_err(dev, "failed to assert reset: %d\n", err);
-		return err;
-	}
-
-	usleep_range(1000, 2000);
-
-	clk_disable_unprepare(hdmi->clk);
-
-	return 0;
-}
-
-static int tegra_hdmi_resume(struct device *dev)
-{
-	struct tegra_hdmi *hdmi = dev_get_drvdata(dev);
-	int err;
-
-	err = clk_prepare_enable(hdmi->clk);
-	if (err < 0) {
-		dev_err(dev, "failed to enable clock: %d\n", err);
-		return err;
-	}
-
-	usleep_range(1000, 2000);
-
-	err = reset_control_deassert(hdmi->rst);
-	if (err < 0) {
-		dev_err(dev, "failed to deassert reset: %d\n", err);
-		clk_disable_unprepare(hdmi->clk);
-		return err;
-	}
-
-	return 0;
-}
-#endif
-
-static const struct dev_pm_ops tegra_hdmi_pm_ops = {
-	SET_RUNTIME_PM_OPS(tegra_hdmi_suspend, tegra_hdmi_resume, NULL)
-};
-
 struct platform_driver tegra_hdmi_driver = {
 	.driver = {
 		.name = "tegra-hdmi",
 		.of_match_table = tegra_hdmi_of_match,
-		.pm = &tegra_hdmi_pm_ops,
 	},
 	.probe = tegra_hdmi_probe,
 	.remove = tegra_hdmi_remove,

drivers/gpu/drm/tegra/hub.c

···
 
 static int tegra_windowgroup_enable(struct tegra_windowgroup *wgrp)
 {
+	int err = 0;
+
 	mutex_lock(&wgrp->lock);
 
 	if (wgrp->usecount == 0) {
-		pm_runtime_get_sync(wgrp->parent);
+		err = host1x_client_resume(wgrp->parent);
+		if (err < 0) {
+			dev_err(wgrp->parent->dev, "failed to resume: %d\n", err);
+			goto unlock;
+		}
+
 		reset_control_deassert(wgrp->rst);
 	}
 
 	wgrp->usecount++;
-	mutex_unlock(&wgrp->lock);
 
-	return 0;
+unlock:
+	mutex_unlock(&wgrp->lock);
+	return err;
 }
 
 static void tegra_windowgroup_disable(struct tegra_windowgroup *wgrp)
···
 			       wgrp->index);
 		}
 
-		pm_runtime_put(wgrp->parent);
+		host1x_client_suspend(wgrp->parent);
 	}
 
 	wgrp->usecount--;
···
 	struct tegra_plane *p = to_tegra_plane(plane);
 	struct tegra_dc *dc;
 	u32 value;
+	int err;
 
 	/* rien ne va plus */
 	if (!old_state || !old_state->crtc)
 		return;
 
 	dc = to_tegra_dc(old_state->crtc);
+
+	err = host1x_client_resume(&dc->client);
+	if (err < 0) {
+		dev_err(dc->dev, "failed to resume: %d\n", err);
+		return;
+	}
 
 	/*
 	 * XXX Legacy helpers seem to sometimes call ->atomic_disable() even
···
 	if (WARN_ON(p->dc == NULL))
 		p->dc = dc;
 
-	pm_runtime_get_sync(dc->dev);
-
 	value = tegra_plane_readl(p, DC_WIN_WIN_OPTIONS);
 	value &= ~WIN_ENABLE;
 	tegra_plane_writel(p, value, DC_WIN_WIN_OPTIONS);
 
 	tegra_dc_remove_shared_plane(dc, p);
 
-	pm_runtime_put(dc->dev);
+	host1x_client_suspend(&dc->client);
 }
 
 static void tegra_shared_plane_atomic_update(struct drm_plane *plane,
···
 	struct tegra_plane *p = to_tegra_plane(plane);
 	dma_addr_t base;
 	u32 value;
+	int err;
 
 	/* rien ne va plus */
 	if (!plane->state->crtc || !plane->state->fb)
···
 		return;
 	}
 
-	pm_runtime_get_sync(dc->dev);
+	err = host1x_client_resume(&dc->client);
+	if (err < 0) {
+		dev_err(dc->dev, "failed to resume: %d\n", err);
+		return;
+	}
 
 	tegra_dc_assign_shared_plane(dc, p);
 
···
 	value &= ~CONTROL_CSC_ENABLE;
 	tegra_plane_writel(p, value, DC_WIN_WINDOW_SET_CONTROL);
 
-	pm_runtime_put(dc->dev);
+	host1x_client_suspend(&dc->client);
 }
 
 static const struct drm_plane_helper_funcs tegra_shared_plane_helper_funcs = {
···
 	plane->base.index = index;
 
 	plane->wgrp = &hub->wgrps[wgrp];
-	plane->wgrp->parent = dc->dev;
+	plane->wgrp->parent = &dc->client;
 
 	p = &plane->base.base;
 
···
 static void tegra_display_hub_update(struct tegra_dc *dc)
 {
 	u32 value;
+	int err;
 
-	pm_runtime_get_sync(dc->dev);
+	err = host1x_client_resume(&dc->client);
+	if (err < 0) {
+		dev_err(dc->dev, "failed to resume: %d\n", err);
+		return;
+	}
 
 	value = tegra_dc_readl(dc, DC_CMD_IHUB_COMMON_MISC_CTL);
 	value &= ~LATENCY_EVENT;
···
 	tegra_dc_writel(dc, COMMON_ACTREQ, DC_CMD_STATE_CONTROL);
 	tegra_dc_readl(dc, DC_CMD_STATE_CONTROL);
 
-	pm_runtime_put(dc->dev);
+	host1x_client_suspend(&dc->client);
 }
 
 void tegra_display_hub_atomic_commit(struct drm_device *drm,
···
 	return 0;
 }
 
+static int tegra_display_hub_runtime_suspend(struct host1x_client *client)
+{
+	struct tegra_display_hub *hub = to_tegra_display_hub(client);
+	struct device *dev = client->dev;
+	unsigned int i = hub->num_heads;
+	int err;
+
+	err = reset_control_assert(hub->rst);
+	if (err < 0)
+		return err;
+
+	while (i--)
+		clk_disable_unprepare(hub->clk_heads[i]);
+
+	clk_disable_unprepare(hub->clk_hub);
+	clk_disable_unprepare(hub->clk_dsc);
+	clk_disable_unprepare(hub->clk_disp);
+
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static int tegra_display_hub_runtime_resume(struct host1x_client *client)
+{
+	struct tegra_display_hub *hub = to_tegra_display_hub(client);
+	struct device *dev = client->dev;
+	unsigned int i;
+	int err;
+
+	err = pm_runtime_get_sync(dev);
+	if (err < 0) {
+		dev_err(dev, "failed to get runtime PM: %d\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(hub->clk_disp);
+	if (err < 0)
+		goto put_rpm;
+
+	err = clk_prepare_enable(hub->clk_dsc);
+	if (err < 0)
+		goto disable_disp;
+
+	err = clk_prepare_enable(hub->clk_hub);
+	if (err < 0)
+		goto disable_dsc;
+
+	for (i = 0; i < hub->num_heads; i++) {
+		err = clk_prepare_enable(hub->clk_heads[i]);
+		if (err < 0)
+			goto disable_heads;
+	}
+
+	err = reset_control_deassert(hub->rst);
+	if (err < 0)
+		goto disable_heads;
+
+	return 0;
+
+disable_heads:
+	while (i--)
+		clk_disable_unprepare(hub->clk_heads[i]);
+
+	clk_disable_unprepare(hub->clk_hub);
+disable_dsc:
+	clk_disable_unprepare(hub->clk_dsc);
+disable_disp:
+	clk_disable_unprepare(hub->clk_disp);
+put_rpm:
+	pm_runtime_put_sync(dev);
+	return err;
+}
+
 static const struct host1x_client_ops tegra_display_hub_ops = {
 	.init = tegra_display_hub_init,
 	.exit = tegra_display_hub_exit,
+	.suspend = tegra_display_hub_runtime_suspend,
+	.resume = tegra_display_hub_runtime_resume,
 };
 
 static int tegra_display_hub_probe(struct platform_device *pdev)
···
 static int tegra_display_hub_remove(struct platform_device *pdev)
 {
 	struct tegra_display_hub *hub = platform_get_drvdata(pdev);
+	unsigned int i;
 	int err;
 
 	err = host1x_client_unregister(&hub->client);
···
 			err);
 	}
 
+	for (i = 0; i < hub->soc->num_wgrps; i++) {
+		struct tegra_windowgroup *wgrp = &hub->wgrps[i];
+
+		mutex_destroy(&wgrp->lock);
+	}
+
 	pm_runtime_disable(&pdev->dev);
 
 	return err;
 }
-
-static int __maybe_unused tegra_display_hub_suspend(struct device *dev)
-{
-	struct tegra_display_hub *hub = dev_get_drvdata(dev);
-	unsigned int i = hub->num_heads;
-	int err;
-
-	err = reset_control_assert(hub->rst);
-	if (err < 0)
-		return err;
-
-	while (i--)
-		clk_disable_unprepare(hub->clk_heads[i]);
-
-	clk_disable_unprepare(hub->clk_hub);
-	clk_disable_unprepare(hub->clk_dsc);
-	clk_disable_unprepare(hub->clk_disp);
-
-	return 0;
-}
-
-static int __maybe_unused tegra_display_hub_resume(struct device *dev)
-{
-	struct tegra_display_hub *hub = dev_get_drvdata(dev);
-	unsigned int i;
-	int err;
-
-	err = clk_prepare_enable(hub->clk_disp);
-	if (err < 0)
-		return err;
-
-	err = clk_prepare_enable(hub->clk_dsc);
-	if (err < 0)
-		goto disable_disp;
-
-	err = clk_prepare_enable(hub->clk_hub);
-	if (err < 0)
-		goto disable_dsc;
-
-	for (i = 0; i < hub->num_heads; i++) {
-		err = clk_prepare_enable(hub->clk_heads[i]);
-		if (err < 0)
-			goto disable_heads;
-	}
-
-	err = reset_control_deassert(hub->rst);
-	if (err < 0)
-		goto disable_heads;
-
-	return 0;
-
-disable_heads:
-	while (i--)
-		clk_disable_unprepare(hub->clk_heads[i]);
-
-	clk_disable_unprepare(hub->clk_hub);
-disable_dsc:
-	clk_disable_unprepare(hub->clk_dsc);
-disable_disp:
-	clk_disable_unprepare(hub->clk_disp);
-	return err;
-}
-
-static const struct dev_pm_ops tegra_display_hub_pm_ops = {
-	SET_RUNTIME_PM_OPS(tegra_display_hub_suspend,
-			   tegra_display_hub_resume, NULL)
-};
 
 static const struct tegra_display_hub_soc tegra186_display_hub = {
 	.num_wgrps = 6,
···
 	.driver = {
 		.name = "tegra-display-hub",
 		.of_match_table = tegra_display_hub_of_match,
-		.pm = &tegra_display_hub_pm_ops,
 	},
 	.probe = tegra_display_hub_probe,
 	.remove = tegra_display_hub_remove,

drivers/gpu/drm/tegra/hub.h

···
 	struct mutex lock;
 
 	unsigned int index;
-	struct device *parent;
+	struct host1x_client *parent;
 	struct reset_control *rst;
 };
 

drivers/gpu/drm/tegra/sor.c

···
 	if (err < 0)
 		dev_err(sor->dev, "failed to power off I/O pad: %d\n", err);
 
-	pm_runtime_put(sor->dev);
+	host1x_client_suspend(&sor->client);
 }
 
 static void tegra_sor_hdmi_enable(struct drm_encoder *encoder)
···
 	mode = &encoder->crtc->state->adjusted_mode;
 	pclk = mode->clock * 1000;
 
-	pm_runtime_get_sync(sor->dev);
+	err = host1x_client_resume(&sor->client);
+	if (err < 0) {
+		dev_err(sor->dev, "failed to resume: %d\n", err);
+		return;
+	}
 
 	/* switch to safe parent clock */
 	err = tegra_sor_set_parent_clock(sor, sor->clk_safe);
···
 	if (output->panel)
 		drm_panel_unprepare(output->panel);
 
-	pm_runtime_put(sor->dev);
+	host1x_client_suspend(&sor->client);
 }
 
 static void tegra_sor_dp_enable(struct drm_encoder *encoder)
···
 	mode = &encoder->crtc->state->adjusted_mode;
 	info = &output->connector.display_info;
 
-	pm_runtime_get_sync(sor->dev);
+	err = host1x_client_resume(&sor->client);
+	if (err < 0) {
+		dev_err(sor->dev, "failed to resume: %d\n", err);
+		return;
+	}
 
 	/* switch to safe parent clock */
 	err = tegra_sor_set_parent_clock(sor, sor->clk_safe);
···
 	return 0;
 }
 
+static int tegra_sor_runtime_suspend(struct host1x_client *client)
+{
+	struct tegra_sor *sor = host1x_client_to_sor(client);
+	struct device *dev = client->dev;
+	int err;
+
+	if (sor->rst) {
+		err = reset_control_assert(sor->rst);
+		if (err < 0) {
+			dev_err(dev, "failed to assert reset: %d\n", err);
+			return err;
+		}
+
+		reset_control_release(sor->rst);
+	}
+
+	usleep_range(1000, 2000);
+
+	clk_disable_unprepare(sor->clk);
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static int tegra_sor_runtime_resume(struct host1x_client *client)
+{
+	struct tegra_sor *sor = host1x_client_to_sor(client);
+	struct device *dev = client->dev;
+	int err;
+
+	err = pm_runtime_get_sync(dev);
+	if (err < 0) {
+		dev_err(dev, "failed to get runtime PM: %d\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(sor->clk);
+	if (err < 0) {
+		dev_err(dev, "failed to enable clock: %d\n", err);
+		goto put_rpm;
+	}
+
+	usleep_range(1000, 2000);
+
+	if (sor->rst) {
+		err = reset_control_acquire(sor->rst);
+		if (err < 0) {
+			dev_err(dev, "failed to acquire reset: %d\n", err);
+			goto disable_clk;
+		}
+
+		err = reset_control_deassert(sor->rst);
+		if (err < 0) {
+			dev_err(dev, "failed to deassert reset: %d\n", err);
+			goto release_reset;
+		}
+	}
+
+	return 0;
+
+release_reset:
+	reset_control_release(sor->rst);
+disable_clk:
+	clk_disable_unprepare(sor->clk);
+put_rpm:
+	pm_runtime_put_sync(dev);
+	return err;
+}
+
 static const struct host1x_client_ops sor_client_ops = {
 	.init = tegra_sor_init,
 	.exit = tegra_sor_exit,
+	.suspend = tegra_sor_runtime_suspend,
+	.resume = tegra_sor_runtime_resume,
 };
 
 static const u8 tegra124_sor_xbar_cfg[5] = {
···
 	if (!sor->clk_pad) {
 		char *name;
 
-		err = pm_runtime_get_sync(&pdev->dev);
+		err = host1x_client_resume(&sor->client);
 		if (err < 0) {
-			dev_err(&pdev->dev, "failed to get runtime PM: %d\n",
-				err);
+			dev_err(sor->dev, "failed to resume: %d\n", err);
 			goto remove;
 		}
 
···
 		}
 
 		sor->clk_pad = tegra_clk_sor_pad_register(sor, name);
-		pm_runtime_put(&pdev->dev);
+		host1x_client_suspend(&sor->client);
 	}
 
 	if (IS_ERR(sor->clk_pad)) {
···
 	return 0;
 }
 
-static int tegra_sor_runtime_suspend(struct device *dev)
-{
-	struct tegra_sor *sor = dev_get_drvdata(dev);
-	int err;
-
-	if (sor->rst) {
-		err = reset_control_assert(sor->rst);
-		if (err < 0) {
-			dev_err(dev, "failed to assert reset: %d\n", err);
-			return err;
-		}
-
-		reset_control_release(sor->rst);
-	}
-
-	usleep_range(1000, 2000);
-
-	clk_disable_unprepare(sor->clk);
-
-	return 0;
-}
-
-static int tegra_sor_runtime_resume(struct device *dev)
-{
-	struct tegra_sor *sor = dev_get_drvdata(dev);
-	int err;
-
-	err = clk_prepare_enable(sor->clk);
-	if (err < 0) {
-		dev_err(dev, "failed to enable clock: %d\n", err);
-		return err;
-	}
-
-	usleep_range(1000, 2000);
-
-	if (sor->rst) {
-		err = reset_control_acquire(sor->rst);
-		if (err < 0) {
-			dev_err(dev, "failed to acquire reset: %d\n", err);
-			clk_disable_unprepare(sor->clk);
-			return err;
-		}
-
-		err = reset_control_deassert(sor->rst);
-		if (err < 0) {
-			dev_err(dev, "failed to deassert reset: %d\n", err);
-			reset_control_release(sor->rst);
-			clk_disable_unprepare(sor->clk);
-			return err;
-		}
-	}
-
-	return 0;
-}
-
 static int tegra_sor_suspend(struct device *dev)
 {
 	struct tegra_sor *sor = dev_get_drvdata(dev);
···
 
 	if (sor->hdmi_supply) {
 		err = regulator_disable(sor->hdmi_supply);
-		if (err < 0)
+		if (err < 0) {
 			return err;
+		}
 	}
 
 	return 0;
···
 }
 
 static const struct dev_pm_ops tegra_sor_pm_ops = {
-	SET_RUNTIME_PM_OPS(tegra_sor_runtime_suspend, tegra_sor_runtime_resume,
-			   NULL)
 	SET_SYSTEM_SLEEP_PM_OPS(tegra_sor_suspend, tegra_sor_resume)
 };
 

drivers/gpu/host1x/bus.c

···
 	struct host1x *host1x;
 	int err;
 
+	INIT_LIST_HEAD(&client->list);
+	mutex_init(&client->lock);
+	client->usecount = 0;
+
 	mutex_lock(&devices_lock);
 
 	list_for_each_entry(host1x, &devices, list) {
···
 	return 0;
 }
 EXPORT_SYMBOL(host1x_client_unregister);
+
+int host1x_client_suspend(struct host1x_client *client)
+{
+	int err = 0;
+
+	mutex_lock(&client->lock);
+
+	if (client->usecount == 1) {
+		if (client->ops && client->ops->suspend) {
+			err = client->ops->suspend(client);
+			if (err < 0)
+				goto unlock;
+		}
+	}
+
+	client->usecount--;
+	dev_dbg(client->dev, "use count: %u\n", client->usecount);
+
+	if (client->parent) {
+		err = host1x_client_suspend(client->parent);
+		if (err < 0)
+			goto resume;
+	}
+
+	goto unlock;
+
+resume:
+	if (client->usecount == 0)
+		if (client->ops && client->ops->resume)
+			client->ops->resume(client);
+
+	client->usecount++;
+unlock:
+	mutex_unlock(&client->lock);
+	return err;
+}
+EXPORT_SYMBOL(host1x_client_suspend);
+
+int host1x_client_resume(struct host1x_client *client)
+{
+	int err = 0;
+
+	mutex_lock(&client->lock);
+
+	if (client->parent) {
+		err = host1x_client_resume(client->parent);
+		if (err < 0)
+			goto unlock;
+	}
+
+	if (client->usecount == 0) {
+		if (client->ops && client->ops->resume) {
+			err = client->ops->resume(client);
+			if (err < 0)
+				goto suspend;
+		}
+	}
+
+	client->usecount++;
+	dev_dbg(client->dev, "use count: %u\n", client->usecount);
+
+	goto unlock;
+
+suspend:
+	if (client->parent)
+		host1x_client_suspend(client->parent);
+unlock:
+	mutex_unlock(&client->lock);
+	return err;
+}
+EXPORT_SYMBOL(host1x_client_resume);

include/linux/host1x.h

···
  * struct host1x_client_ops - host1x client operations
  * @init: host1x client initialization code
  * @exit: host1x client tear down code
+ * @suspend: host1x client suspend code
+ * @resume: host1x client resume code
  */
 struct host1x_client_ops {
 	int (*init)(struct host1x_client *client);
 	int (*exit)(struct host1x_client *client);
+	int (*suspend)(struct host1x_client *client);
+	int (*resume)(struct host1x_client *client);
 };
 
 /**
···
 
 	struct host1x_syncpt **syncpts;
 	unsigned int num_syncpts;
+
+	struct host1x_client *parent;
+	unsigned int usecount;
+	struct mutex lock;
 };
 
 /*
···
 
 int host1x_client_register(struct host1x_client *client);
 int host1x_client_unregister(struct host1x_client *client);
+
+int host1x_client_suspend(struct host1x_client *client);
+int host1x_client_resume(struct host1x_client *client);
 
 struct tegra_mipi_device;