drm/atmel-hlcdc: Fix suspend/resume implementation

The current suspend resume implementation is assuming register values are
kept when entering suspend, which is no longer the case with the
suspend-to-RAM on the sama5d2.

While at it, switch to the generic infrastructure to enter suspend mode
(drm_atomic_helper_suspend/resume()).
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1488371461-22243-1-git-send-email-boris.brezillon@free-electrons.com

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_crtc.c

@@ -55,14 +55,12 @@ drm_crtc_state_to_atmel_hlcdc_crtc_state(struct drm_crtc_state *state)
  * @hlcdc: pointer to the atmel_hlcdc structure provided by the MFD device
  * @event: pointer to the current page flip event
  * @id: CRTC id (returned by drm_crtc_index)
- * @enabled: CRTC state
  */
 struct atmel_hlcdc_crtc {
 	struct drm_crtc base;
 	struct atmel_hlcdc_dc *dc;
 	struct drm_pending_vblank_event *event;
 	int id;
-	bool enabled;
 };
 
 static inline struct atmel_hlcdc_crtc *
@@ -158,9 +156,6 @@ static void atmel_hlcdc_crtc_disable(struct drm_crtc *c)
 	struct regmap *regmap = crtc->dc->hlcdc->regmap;
 	unsigned int status;
 
-	if (!crtc->enabled)
-		return;
-
 	drm_crtc_vblank_off(c);
 
 	pm_runtime_get_sync(dev->dev);
@@ -186,8 +181,6 @@ static void atmel_hlcdc_crtc_disable(struct drm_crtc *c)
 	pm_runtime_allow(dev->dev);
 
 	pm_runtime_put_sync(dev->dev);
-
-	crtc->enabled = false;
 }
 
 static void atmel_hlcdc_crtc_enable(struct drm_crtc *c)
@@ -197,9 +190,6 @@ static void atmel_hlcdc_crtc_enable(struct drm_crtc *c)
 	struct regmap *regmap = crtc->dc->hlcdc->regmap;
 	unsigned int status;
 
-	if (crtc->enabled)
-		return;
-
 	pm_runtime_get_sync(dev->dev);
 
 	pm_runtime_forbid(dev->dev);
@@ -226,29 +216,6 @@ static void atmel_hlcdc_crtc_enable(struct drm_crtc *c)
 	pm_runtime_put_sync(dev->dev);
 
 	drm_crtc_vblank_on(c);
-
-	crtc->enabled = true;
-}
-
-void atmel_hlcdc_crtc_suspend(struct drm_crtc *c)
-{
-	struct atmel_hlcdc_crtc *crtc = drm_crtc_to_atmel_hlcdc_crtc(c);
-
-	if (crtc->enabled) {
-		atmel_hlcdc_crtc_disable(c);
-		/* save enable state for resume */
-		crtc->enabled = true;
-	}
-}
-
-void atmel_hlcdc_crtc_resume(struct drm_crtc *c)
-{
-	struct atmel_hlcdc_crtc *crtc = drm_crtc_to_atmel_hlcdc_crtc(c);
-
-	if (crtc->enabled) {
-		crtc->enabled = false;
-		atmel_hlcdc_crtc_enable(c);
-	}
 }
 
 #define ATMEL_HLCDC_RGB444_OUTPUT	BIT(0)

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c

@@ -800,31 +800,32 @@ static int atmel_hlcdc_dc_drm_remove(struct platform_device *pdev)
 static int atmel_hlcdc_dc_drm_suspend(struct device *dev)
 {
 	struct drm_device *drm_dev = dev_get_drvdata(dev);
-	struct drm_crtc *crtc;
+	struct atmel_hlcdc_dc *dc = drm_dev->dev_private;
+	struct regmap *regmap = dc->hlcdc->regmap;
+	struct drm_atomic_state *state;
+
+	state = drm_atomic_helper_suspend(drm_dev);
+	if (IS_ERR(state))
+		return PTR_ERR(state);
 
-	if (pm_runtime_suspended(dev))
-		return 0;
+	dc->suspend.state = state;
+
+	regmap_read(regmap, ATMEL_HLCDC_IMR, &dc->suspend.imr);
+	regmap_write(regmap, ATMEL_HLCDC_IDR, dc->suspend.imr);
+	clk_disable_unprepare(dc->hlcdc->periph_clk);
 
-	drm_modeset_lock_all(drm_dev);
-	list_for_each_entry(crtc, &drm_dev->mode_config.crtc_list, head)
-		atmel_hlcdc_crtc_suspend(crtc);
-	drm_modeset_unlock_all(drm_dev);
 	return 0;
 }
 
 static int atmel_hlcdc_dc_drm_resume(struct device *dev)
 {
 	struct drm_device *drm_dev = dev_get_drvdata(dev);
-	struct drm_crtc *crtc;
+	struct atmel_hlcdc_dc *dc = drm_dev->dev_private;
 
-	if (pm_runtime_suspended(dev))
-		return 0;
+	clk_prepare_enable(dc->hlcdc->periph_clk);
+	regmap_write(dc->hlcdc->regmap, ATMEL_HLCDC_IER, dc->suspend.imr);
 
-	drm_modeset_lock_all(drm_dev);
-	list_for_each_entry(crtc, &drm_dev->mode_config.crtc_list, head)
-		atmel_hlcdc_crtc_resume(crtc);
-	drm_modeset_unlock_all(drm_dev);
-	return 0;
+	return drm_atomic_helper_resume(drm_dev, dc->suspend.state);
 }
 #endif
 

drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.h

@@ -358,6 +358,7 @@ struct atmel_hlcdc_plane_properties {
  * @planes: instantiated planes
  * @layers: active HLCDC layers
  * @wq: display controller workqueue
+ * @suspend: used to store the HLCDC state when entering suspend
  * @commit: used for async commit handling
  */
 struct atmel_hlcdc_dc {
@@ -368,6 +369,10 @@ struct atmel_hlcdc_dc {
 	struct drm_crtc *crtc;
 	struct atmel_hlcdc_layer *layers[ATMEL_HLCDC_MAX_LAYERS];
 	struct workqueue_struct *wq;
+	struct {
+		u32 imr;
+		struct drm_atomic_state *state;
+	} suspend;
 	struct {
 		wait_queue_head_t wait;
 		bool pending;
@@ -428,9 +433,6 @@ int atmel_hlcdc_plane_prepare_ahb_routing(struct drm_crtc_state *c_state);
 
 void atmel_hlcdc_crtc_irq(struct drm_crtc *c);
 
-void atmel_hlcdc_crtc_suspend(struct drm_crtc *crtc);
-void atmel_hlcdc_crtc_resume(struct drm_crtc *crtc);
-
 int atmel_hlcdc_crtc_create(struct drm_device *dev);
 
 int atmel_hlcdc_create_outputs(struct drm_device *dev);