drm/tegra: Implement page-flipping support

All the necessary support bits like .mode_set_base() and VBLANK are now
available, so page-flipping case easily be implemented on top.

Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>

4 files changed, 82 insertions, 0 deletions

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 5f55a25424a7..c5d825fd25fe 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -183,7 +183,72 @@ void tegra_dc_disable_vblank(struct tegra_dc *dc)
         spin_unlock_irqrestore(&dc->lock, flags);
 }
 
+static void tegra_dc_finish_page_flip(struct tegra_dc *dc)
+{
+        struct drm_device *drm = dc->base.dev;
+        struct drm_crtc *crtc = &dc->base;
+        struct drm_gem_cma_object *gem;
+        unsigned long flags, base;
+
+        if (!dc->event)
+                return;
+
+        gem = drm_fb_cma_get_gem_obj(crtc->fb, 0);
+
+        /* check if new start address has been latched */
+        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);
+
+        if (base == gem->paddr + crtc->fb->offsets[0]) {
+                spin_lock_irqsave(&drm->event_lock, flags);
+                drm_send_vblank_event(drm, dc->pipe, dc->event);
+                drm_vblank_put(drm, dc->pipe);
+                dc->event = NULL;
+                spin_unlock_irqrestore(&drm->event_lock, flags);
+        }
+}
+
+void tegra_dc_cancel_page_flip(struct drm_crtc *crtc, struct drm_file *file)
+{
+        struct tegra_dc *dc = to_tegra_dc(crtc);
+        struct drm_device *drm = crtc->dev;
+        unsigned long flags;
+
+        spin_lock_irqsave(&drm->event_lock, flags);
+
+        if (dc->event && dc->event->base.file_priv == file) {
+                dc->event->base.destroy(&dc->event->base);
+                drm_vblank_put(drm, dc->pipe);
+                dc->event = NULL;
+        }
+
+        spin_unlock_irqrestore(&drm->event_lock, flags);
+}
+
+static int tegra_dc_page_flip(struct drm_crtc *crtc, struct drm_framebuffer *fb,
+                              struct drm_pending_vblank_event *event)
+{
+        struct tegra_dc *dc = to_tegra_dc(crtc);
+        struct drm_device *drm = crtc->dev;
+
+        if (dc->event)
+                return -EBUSY;
+
+        if (event) {
+                event->pipe = dc->pipe;
+                dc->event = event;
+                drm_vblank_get(drm, dc->pipe);
+        }
+
+        tegra_dc_set_base(dc, 0, 0, fb);
+        crtc->fb = fb;
+
+        return 0;
+}
+
 static const struct drm_crtc_funcs tegra_crtc_funcs = {
+        .page_flip = tegra_dc_page_flip,
         .set_config = drm_crtc_helper_set_config,
         .destroy = drm_crtc_cleanup,
 };
@@ -665,6 +730,7 @@ static irqreturn_t tegra_dc_irq(int irq, void *data)
                 dev_dbg(dc->dev, "%s(): vertical blank\n", __func__);
                 */
                 drm_handle_vblank(dc->base.dev, dc->pipe);
+                tegra_dc_finish_page_flip(dc);
         }
 
         if (status & (WIN_A_UF_INT | WIN_B_UF_INT | WIN_C_UF_INT)) {
diff --git a/drivers/gpu/drm/tegra/dc.h b/drivers/gpu/drm/tegra/dc.h
index e2fa328861ca..79eaec9aac77 100644
--- a/drivers/gpu/drm/tegra/dc.h
+++ b/drivers/gpu/drm/tegra/dc.h
@@ -58,6 +58,8 @@
 #define DC_CMD_SIGNAL_RAISE3                    0x03e
 
 #define DC_CMD_STATE_ACCESS                     0x040
+#define READ_MUX  (1 << 0)
+#define WRITE_MUX (1 << 2)
 
 #define DC_CMD_STATE_CONTROL                    0x041
 #define GENERAL_ACT_REQ (1 <<  0)
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 4e31dace5275..97485af6eaf9 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -135,11 +135,20 @@ static void tegra_drm_disable_vblank(struct drm_device *drm, int pipe)
                 tegra_dc_disable_vblank(dc);
 }
 
+static void tegra_drm_preclose(struct drm_device *drm, struct drm_file *file)
+{
+        struct drm_crtc *crtc;
+
+        list_for_each_entry(crtc, &drm->mode_config.crtc_list, head)
+                tegra_dc_cancel_page_flip(crtc, file);
+}
+
 struct drm_driver tegra_drm_driver = {
         .driver_features = DRIVER_BUS_PLATFORM | DRIVER_MODESET | DRIVER_GEM,
         .load = tegra_drm_load,
         .unload = tegra_drm_unload,
         .open = tegra_drm_open,
+        .preclose = tegra_drm_preclose,
         .lastclose = tegra_drm_lastclose,
 
         .get_vblank_counter = tegra_drm_get_vblank_counter,
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index 01f0aee12ad9..6dd75a2600eb 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -84,6 +84,9 @@ struct tegra_dc {
         struct drm_info_list *debugfs_files;
         struct drm_minor *minor;
         struct dentry *debugfs;
+
+        /* page-flip handling */
+        struct drm_pending_vblank_event *event;
 };
 
 static inline struct tegra_dc *host1x_client_to_dc(struct host1x_client *client)
@@ -133,6 +136,8 @@ extern int tegra_dc_setup_window(struct tegra_dc *dc, unsigned int index,
                                  const struct tegra_dc_window *window);
 extern void tegra_dc_enable_vblank(struct tegra_dc *dc);
 extern void tegra_dc_disable_vblank(struct tegra_dc *dc);
+extern void tegra_dc_cancel_page_flip(struct drm_crtc *crtc,
+                                      struct drm_file *file);
 
 struct tegra_output_ops {
         int (*enable)(struct tegra_output *output);