drm/tegra: Implement VBLANK support

Implement support for the VBLANK IOCTL. Note that Tegra is somewhat
special in this case because it doesn't use the generic IRQ support
provided by the DRM core (DRIVER_HAVE_IRQ) but rather registers one
interrupt handler for each display controller.

While at it, clean up the way that interrupts are enabled to ensure
that the VBLANK interrupt only gets enabled when required.

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

1 files changed, 38 insertions, 17 deletions

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index ceb2f52c8f7e..5f55a25424a7 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -157,6 +157,32 @@ static int tegra_dc_set_base(struct tegra_dc *dc, int x, int y,
 	return 0;
 }
 
+void tegra_dc_enable_vblank(struct tegra_dc *dc)
+{
+	unsigned long value, flags;
+
+	spin_lock_irqsave(&dc->lock, flags);
+
+	value = tegra_dc_readl(dc, DC_CMD_INT_MASK);
+	value |= VBLANK_INT;
+	tegra_dc_writel(dc, value, DC_CMD_INT_MASK);
+
+	spin_unlock_irqrestore(&dc->lock, flags);
+}
+
+void tegra_dc_disable_vblank(struct tegra_dc *dc)
+{
+	unsigned long value, flags;
+
+	spin_lock_irqsave(&dc->lock, flags);
+
+	value = tegra_dc_readl(dc, DC_CMD_INT_MASK);
+	value &= ~VBLANK_INT;
+	tegra_dc_writel(dc, value, DC_CMD_INT_MASK);
+
+	spin_unlock_irqrestore(&dc->lock, flags);
+}
+
 static const struct drm_crtc_funcs tegra_crtc_funcs = {
 	.set_config = drm_crtc_helper_set_config,
 	.destroy = drm_crtc_cleanup,
@@ -485,6 +511,8 @@ static int tegra_crtc_mode_set(struct drm_crtc *crtc,
 	unsigned long div, value;
 	int err;
 
+	drm_vblank_pre_modeset(crtc->dev, dc->pipe);
+
 	err = tegra_crtc_setup_clk(crtc, mode, &div);
 	if (err) {
 		dev_err(dc->dev, "failed to setup clock for CRTC: %d\n", err);
@@ -585,31 +613,23 @@ static void tegra_crtc_prepare(struct drm_crtc *crtc)
 	tegra_dc_writel(dc, value, DC_DISP_DISP_MEM_HIGH_PRIORITY_TIMER);
 
 	value = VBLANK_INT | WIN_A_UF_INT | WIN_B_UF_INT | WIN_C_UF_INT;
-	tegra_dc_writel(dc, value, DC_CMD_INT_MASK);
-
-	value = VBLANK_INT | WIN_A_UF_INT | WIN_B_UF_INT | WIN_C_UF_INT;
 	tegra_dc_writel(dc, value, DC_CMD_INT_ENABLE);
+
+	value = WIN_A_UF_INT | WIN_B_UF_INT | WIN_C_UF_INT;
+	tegra_dc_writel(dc, value, DC_CMD_INT_MASK);
 }
 
 static void tegra_crtc_commit(struct drm_crtc *crtc)
 {
 	struct tegra_dc *dc = to_tegra_dc(crtc);
-	unsigned long update_mask;
 	unsigned long value;
 
-	update_mask = GENERAL_ACT_REQ | WIN_A_ACT_REQ;
-
-	tegra_dc_writel(dc, update_mask << 8, DC_CMD_STATE_CONTROL);
-
-	value = tegra_dc_readl(dc, DC_CMD_INT_ENABLE);
-	value |= FRAME_END_INT;
-	tegra_dc_writel(dc, value, DC_CMD_INT_ENABLE);
+	value = GENERAL_ACT_REQ | WIN_A_ACT_REQ |
+		GENERAL_UPDATE | WIN_A_UPDATE;
 
-	value = tegra_dc_readl(dc, DC_CMD_INT_MASK);
-	value |= FRAME_END_INT;
-	tegra_dc_writel(dc, value, DC_CMD_INT_MASK);
+	tegra_dc_writel(dc, value, DC_CMD_STATE_CONTROL);
 
-	tegra_dc_writel(dc, update_mask, DC_CMD_STATE_CONTROL);
+	drm_vblank_post_modeset(crtc->dev, dc->pipe);
 }
 
 static void tegra_crtc_load_lut(struct drm_crtc *crtc)
@@ -626,7 +646,7 @@ static const struct drm_crtc_helper_funcs tegra_crtc_helper_funcs = {
 	.load_lut = tegra_crtc_load_lut,
 };
 
-static irqreturn_t tegra_drm_irq(int irq, void *data)
+static irqreturn_t tegra_dc_irq(int irq, void *data)
 {
 	struct tegra_dc *dc = data;
 	unsigned long status;
@@ -971,7 +991,7 @@ static int tegra_dc_drm_init(struct host1x_client *client,
 			dev_err(dc->dev, "debugfs setup failed: %d\n", err);
 	}
 
-	err = devm_request_irq(dc->dev, dc->irq, tegra_drm_irq, 0,
+	err = devm_request_irq(dc->dev, dc->irq, tegra_dc_irq, 0,
 			       dev_name(dc->dev), dc);
 	if (err < 0) {
 		dev_err(dc->dev, "failed to request IRQ#%u: %d\n", dc->irq,
@@ -1020,6 +1040,7 @@ static int tegra_dc_probe(struct platform_device *pdev)
 	if (!dc)
 		return -ENOMEM;
 
+	spin_lock_init(&dc->lock);
 	INIT_LIST_HEAD(&dc->list);
 	dc->dev = &pdev->dev;