drm/tegra: Use atomic commit helpers

There's no reason not to use them, and they already get all the
semantics right, so rip out all of the custom code and replace it by the
helpers.
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dc.c

@@ -1648,8 +1648,8 @@ static void tegra_dc_finish_page_flip(struct tegra_dc *dc)
 {
 	struct drm_device *drm = dc->base.dev;
 	struct drm_crtc *crtc = &dc->base;
-	unsigned long flags, base;
-	struct tegra_bo *bo;
+	u64 base = 0, phys = 0;
+	unsigned long flags;
 
 	spin_lock_irqsave(&drm->event_lock, flags);
 
@@ -1658,19 +1658,24 @@ static void tegra_dc_finish_page_flip(struct tegra_dc *dc)
 		return;
 	}
 
-	bo = tegra_fb_get_plane(crtc->primary->fb, 0);
+	if (crtc->primary->fb) {
+		struct tegra_bo *bo = tegra_fb_get_plane(crtc->primary->fb, 0);
 
-	spin_lock(&dc->lock);
+		phys = bo->paddr + crtc->primary->fb->offsets[0];
 
-	/* check if new start address has been latched */
-	tegra_dc_writel(dc, WINDOW_A_SELECT, DC_CMD_DISPLAY_WINDOW_HEADER);
-	tegra_dc_writel(dc, READ_MUX, DC_CMD_STATE_ACCESS);
-	base = tegra_dc_readl(dc, DC_WINBUF_START_ADDR);
-	tegra_dc_writel(dc, 0, DC_CMD_STATE_ACCESS);
+		spin_lock(&dc->lock);
 
-	spin_unlock(&dc->lock);
+		/* check if new start address has been latched */
+		tegra_dc_writel(dc, WINDOW_A_SELECT, DC_CMD_DISPLAY_WINDOW_HEADER);
+		tegra_dc_writel(dc, READ_MUX, DC_CMD_STATE_ACCESS);
+		base = (u64)tegra_dc_readl(dc, DC_WINBUF_START_ADDR_HI) << 32;
+		base |= tegra_dc_readl(dc, DC_WINBUF_START_ADDR);
+		tegra_dc_writel(dc, 0, DC_CMD_STATE_ACCESS);
+
+		spin_unlock(&dc->lock);
+	}
 
-	if (base == bo->paddr + crtc->primary->fb->offsets[0]) {
+	if (base == phys) {
 		drm_crtc_send_vblank_event(crtc, dc->event);
 		drm_crtc_vblank_put(crtc);
 		dc->event = NULL;

drivers/gpu/drm/tegra/dc.h

@@ -579,6 +579,8 @@ int tegra_dc_rgb_exit(struct tegra_dc *dc);
 #define DC_WINBUF_SURFACE_KIND_BLOCK	(2 << 0)
 #define DC_WINBUF_SURFACE_KIND_BLOCK_HEIGHT(x) (((x) & 0x7) << 4)
 
+#define DC_WINBUF_START_ADDR_HI			0x80d
+
 #define DC_WINBUF_AD_UFLOW_STATUS		0xbca
 #define DC_WINBUF_BD_UFLOW_STATUS		0xdca
 #define DC_WINBUF_CD_UFLOW_STATUS		0xfca

drivers/gpu/drm/tegra/drm.c

@@ -33,97 +33,18 @@ struct tegra_drm_file {
 	struct mutex lock;
 };
 
-static void tegra_atomic_schedule(struct tegra_drm *tegra,
-				  struct drm_atomic_state *state)
-{
-	tegra->commit.state = state;
-	schedule_work(&tegra->commit.work);
-}
-
-static void tegra_atomic_complete(struct tegra_drm *tegra,
-				  struct drm_atomic_state *state)
-{
-	struct drm_device *drm = tegra->drm;
-
-	/*
-	 * Everything below can be run asynchronously without the need to grab
-	 * any modeset locks at all under one condition: It must be guaranteed
-	 * that the asynchronous work has either been cancelled (if the driver
-	 * supports it, which at least requires that the framebuffers get
-	 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed
-	 * before the new state gets committed on the software side with
-	 * drm_atomic_helper_swap_state().
-	 *
-	 * This scheme allows new atomic state updates to be prepared and
-	 * checked in parallel to the asynchronous completion of the previous
-	 * update. Which is important since compositors need to figure out the
-	 * composition of the next frame right after having submitted the
-	 * current layout.
-	 */
-
-	drm_atomic_helper_commit_modeset_disables(drm, state);
-	drm_atomic_helper_commit_modeset_enables(drm, state);
-	drm_atomic_helper_commit_planes(drm, state,
-					DRM_PLANE_COMMIT_ACTIVE_ONLY);
-
-	drm_atomic_helper_wait_for_vblanks(drm, state);
-
-	drm_atomic_helper_cleanup_planes(drm, state);
-	drm_atomic_state_put(state);
-}
-
-static void tegra_atomic_work(struct work_struct *work)
-{
-	struct tegra_drm *tegra = container_of(work, struct tegra_drm,
-					       commit.work);
-
-	tegra_atomic_complete(tegra, tegra->commit.state);
-}
-
-static int tegra_atomic_commit(struct drm_device *drm,
-			       struct drm_atomic_state *state, bool nonblock)
-{
-	struct tegra_drm *tegra = drm->dev_private;
-	int err;
-
-	err = drm_atomic_helper_prepare_planes(drm, state);
-	if (err)
-		return err;
-
-	/* serialize outstanding nonblocking commits */
-	mutex_lock(&tegra->commit.lock);
-	flush_work(&tegra->commit.work);
-
-	/*
-	 * This is the point of no return - everything below never fails except
-	 * when the hw goes bonghits. Which means we can commit the new state on
-	 * the software side now.
-	 */
-
-	err = drm_atomic_helper_swap_state(state, true);
-	if (err) {
-		mutex_unlock(&tegra->commit.lock);
-		drm_atomic_helper_cleanup_planes(drm, state);
-		return err;
-	}
-
-	drm_atomic_state_get(state);
-	if (nonblock)
-		tegra_atomic_schedule(tegra, state);
-	else
-		tegra_atomic_complete(tegra, state);
-
-	mutex_unlock(&tegra->commit.lock);
-	return 0;
-}
-
-static const struct drm_mode_config_funcs tegra_drm_mode_funcs = {
+static const struct drm_mode_config_funcs tegra_drm_mode_config_funcs = {
 	.fb_create = tegra_fb_create,
 #ifdef CONFIG_DRM_FBDEV_EMULATION
 	.output_poll_changed = tegra_fb_output_poll_changed,
 #endif
 	.atomic_check = drm_atomic_helper_check,
-	.atomic_commit = tegra_atomic_commit,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+static const struct drm_mode_config_helper_funcs
+tegra_drm_mode_config_helpers = {
+	.atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
 };
 
 static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
@@ -172,9 +93,6 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
 	mutex_init(&tegra->clients_lock);
 	INIT_LIST_HEAD(&tegra->clients);
 
-	mutex_init(&tegra->commit.lock);
-	INIT_WORK(&tegra->commit.work, tegra_atomic_work);
-
 	drm->dev_private = tegra;
 	tegra->drm = drm;
 
@@ -188,7 +106,8 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
 
 	drm->mode_config.allow_fb_modifiers = true;
 
-	drm->mode_config.funcs = &tegra_drm_mode_funcs;
+	drm->mode_config.funcs = &tegra_drm_mode_config_funcs;
+	drm->mode_config.helper_private = &tegra_drm_mode_config_helpers;
 
 	err = tegra_drm_fb_prepare(drm);
 	if (err < 0)

drivers/gpu/drm/tegra/drm.h

@@ -62,12 +62,6 @@ struct tegra_drm {
 
 	unsigned int pitch_align;
 
-	struct {
-		struct drm_atomic_state *state;
-		struct work_struct work;
-		struct mutex lock;
-	} commit;
-
 	struct drm_atomic_state *state;
 };