drm/tegra: dc: Implement hardware VBLANK counter

The display controller on Tegra can use syncpoints to count VBLANK
events. syncpoints are 32-bit unsigned integers, so well suited as
VBLANK counters.

Signed-off-by: Thierry Reding <treding@nvidia.com>

4 files changed, 35 insertions, 13 deletions

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 8746a9ce6a8f..9e329465ab11 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -906,6 +906,15 @@ static int tegra_dc_add_planes(struct drm_device *drm, struct tegra_dc *dc)
         return 0;
 }
 
+u32 tegra_dc_get_vblank_counter(struct tegra_dc *dc)
+{
+        if (dc->syncpt)
+                return host1x_syncpt_read(dc->syncpt);
+
+        /* fallback to software emulated VBLANK counter */
+        return drm_crtc_vblank_count(&dc->base);
+}
+
 void tegra_dc_enable_vblank(struct tegra_dc *dc)
 {
         unsigned long value, flags;
@@ -1632,7 +1641,6 @@ static int tegra_dc_init(struct host1x_client *client)
         struct tegra_drm *tegra = drm->dev_private;
         struct drm_plane *primary = NULL;
         struct drm_plane *cursor = NULL;
-        unsigned int syncpt;
         u32 value;
         int err;
 
@@ -1701,13 +1709,15 @@ static int tegra_dc_init(struct host1x_client *client)
         }
 
         /* initialize display controller */
-        if (dc->pipe)
-                syncpt = SYNCPT_VBLANK1;
-        else
-                syncpt = SYNCPT_VBLANK0;
+        if (dc->syncpt) {
+                u32 syncpt = host1x_syncpt_id(dc->syncpt);
 
-        tegra_dc_writel(dc, 0x00000100, DC_CMD_GENERAL_INCR_SYNCPT_CNTRL);
-        tegra_dc_writel(dc, 0x100 | syncpt, DC_CMD_CONT_SYNCPT_VSYNC);
+                value = SYNCPT_CNTRL_NO_STALL;
+                tegra_dc_writel(dc, value, DC_CMD_GENERAL_INCR_SYNCPT_CNTRL);
+
+                value = SYNCPT_VSYNC_ENABLE | syncpt;
+                tegra_dc_writel(dc, value, DC_CMD_CONT_SYNCPT_VSYNC);
+        }
 
         value = WIN_A_UF_INT | WIN_B_UF_INT | WIN_C_UF_INT | WIN_A_OF_INT;
         tegra_dc_writel(dc, value, DC_CMD_INT_TYPE);
@@ -1875,6 +1885,7 @@ static int tegra_dc_parse_dt(struct tegra_dc *dc)
 
 static int tegra_dc_probe(struct platform_device *pdev)
 {
+        unsigned long flags = HOST1X_SYNCPT_CLIENT_MANAGED;
         const struct of_device_id *id;
         struct resource *regs;
         struct tegra_dc *dc;
@@ -1966,6 +1977,10 @@ static int tegra_dc_probe(struct platform_device *pdev)
                 return err;
         }
 
+        dc->syncpt = host1x_syncpt_request(&pdev->dev, flags);
+        if (!dc->syncpt)
+                dev_warn(&pdev->dev, "failed to allocate syncpoint\n");
+
         platform_set_drvdata(pdev, dc);
 
         return 0;
@@ -1976,6 +1991,8 @@ static int tegra_dc_remove(struct platform_device *pdev)
         struct tegra_dc *dc = platform_get_drvdata(pdev);
         int err;
 
+        host1x_syncpt_free(dc->syncpt);
+
         err = host1x_client_unregister(&dc->client);
         if (err < 0) {
                 dev_err(&pdev->dev, "failed to unregister host1x client: %d\n",
diff --git a/drivers/gpu/drm/tegra/dc.h b/drivers/gpu/drm/tegra/dc.h
index 705c93b00794..55792daabbb5 100644
--- a/drivers/gpu/drm/tegra/dc.h
+++ b/drivers/gpu/drm/tegra/dc.h
@@ -12,6 +12,8 @@
 
 #define DC_CMD_GENERAL_INCR_SYNCPT              0x000
 #define DC_CMD_GENERAL_INCR_SYNCPT_CNTRL        0x001
+#define  SYNCPT_CNTRL_NO_STALL   (1 << 8)
+#define  SYNCPT_CNTRL_SOFT_RESET (1 << 0)
 #define DC_CMD_GENERAL_INCR_SYNCPT_ERROR        0x002
 #define DC_CMD_WIN_A_INCR_SYNCPT                0x008
 #define DC_CMD_WIN_A_INCR_SYNCPT_CNTRL          0x009
@@ -23,6 +25,7 @@
 #define DC_CMD_WIN_C_INCR_SYNCPT_CNTRL          0x019
 #define DC_CMD_WIN_C_INCR_SYNCPT_ERROR          0x01a
 #define DC_CMD_CONT_SYNCPT_VSYNC                0x028
+#define  SYNCPT_VSYNC_ENABLE (1 << 8)
 #define DC_CMD_DISPLAY_COMMAND_OPTION0          0x031
 #define DC_CMD_DISPLAY_COMMAND                  0x032
 #define DISP_CTRL_MODE_STOP (0 << 5)
@@ -438,8 +441,4 @@
 #define DC_WINBUF_BD_UFLOW_STATUS               0xdca
 #define DC_WINBUF_CD_UFLOW_STATUS               0xfca
 
-/* synchronization points */
-#define SYNCPT_VBLANK0 26
-#define SYNCPT_VBLANK1 27
-
 #endif /* TEGRA_DC_H */
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 7ba7e2860ac8..8de17f9e5fe1 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -172,6 +172,10 @@ static int tegra_drm_load(struct drm_device *drm, unsigned long flags)
          */
         drm->irq_enabled = true;
 
+        /* syncpoints are used for full 32-bit hardware VBLANK counters */
+        drm->vblank_disable_immediate = true;
+        drm->max_vblank_count = 0xffffffff;
+
         err = drm_vblank_init(drm, drm->mode_config.num_crtc);
         if (err < 0)
                 goto device;
@@ -813,12 +817,12 @@ static struct drm_crtc *tegra_crtc_from_pipe(struct drm_device *drm,
 static u32 tegra_drm_get_vblank_counter(struct drm_device *drm, int pipe)
 {
         struct drm_crtc *crtc = tegra_crtc_from_pipe(drm, pipe);
+        struct tegra_dc *dc = to_tegra_dc(crtc);
 
         if (!crtc)
                 return 0;
 
-        /* TODO: implement real hardware counter using syncpoints */
-        return drm_crtc_vblank_count(crtc);
+        return tegra_dc_get_vblank_counter(dc);
 }
 
 static int tegra_drm_enable_vblank(struct drm_device *drm, int pipe)
diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index 8cb2dfeaa957..ded04e3473e9 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -106,6 +106,7 @@ struct tegra_output;
 
 struct tegra_dc {
         struct host1x_client client;
+        struct host1x_syncpt *syncpt;
         struct device *dev;
         spinlock_t lock;
 
@@ -180,6 +181,7 @@ struct tegra_dc_window {
 };
 
 /* from dc.c */
+u32 tegra_dc_get_vblank_counter(struct tegra_dc *dc);
 void tegra_dc_enable_vblank(struct tegra_dc *dc);
 void tegra_dc_disable_vblank(struct tegra_dc *dc);
 void tegra_dc_cancel_page_flip(struct drm_crtc *crtc, struct drm_file *file);