drm/tegra: Support bottom-up buffer objects

The gr3d engine renders images bottom-up. Allow buffers that are used
for 3D content to be marked as such and implement support in the display
controller to present them properly.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/dc.c

@@ -47,6 +47,7 @@ static int tegra_plane_update(struct drm_plane *plane, struct drm_crtc *crtc,
 	window.dst.h = crtc_h;
 	window.format = tegra_dc_format(fb->pixel_format);
 	window.bits_per_pixel = fb->bits_per_pixel;
+	window.bottom_up = tegra_fb_is_bottom_up(fb);
 	window.tiled = tegra_fb_is_tiled(fb);
 
 	for (i = 0; i < drm_format_num_planes(fb->pixel_format); i++) {
@@ -147,6 +148,7 @@ static int tegra_dc_set_base(struct tegra_dc *dc, int x, int y,
 {
 	unsigned int format = tegra_dc_format(fb->pixel_format);
 	struct tegra_bo *bo = tegra_fb_get_plane(fb, 0);
+	unsigned int h_offset = 0, v_offset = 0;
 	unsigned long value;
 
 	tegra_dc_writel(dc, WINDOW_A_SELECT, DC_CMD_DISPLAY_WINDOW_HEADER);
@@ -168,6 +170,22 @@ static int tegra_dc_set_base(struct tegra_dc *dc, int x, int y,
 
 	tegra_dc_writel(dc, value, DC_WIN_BUFFER_ADDR_MODE);
 
+	/* make sure bottom-up buffers are properly displayed */
+	if (tegra_fb_is_bottom_up(fb)) {
+		value = tegra_dc_readl(dc, DC_WIN_WIN_OPTIONS);
+		value |= INVERT_V;
+		tegra_dc_writel(dc, value, DC_WIN_WIN_OPTIONS);
+
+		v_offset += fb->height - 1;
+	} else {
+		value = tegra_dc_readl(dc, DC_WIN_WIN_OPTIONS);
+		value &= ~INVERT_V;
+		tegra_dc_writel(dc, value, DC_WIN_WIN_OPTIONS);
+	}
+
+	tegra_dc_writel(dc, h_offset, DC_WINBUF_ADDR_H_OFFSET);
+	tegra_dc_writel(dc, v_offset, DC_WINBUF_ADDR_V_OFFSET);
+
 	value = GENERAL_UPDATE | WIN_A_UPDATE;
 	tegra_dc_writel(dc, value, DC_CMD_STATE_CONTROL);
 
@@ -517,6 +535,9 @@ int tegra_dc_setup_window(struct tegra_dc *dc, unsigned int index,
 		tegra_dc_writel(dc, window->stride[0], DC_WIN_LINE_STRIDE);
 	}
 
+	if (window->bottom_up)
+		v_offset += window->src.h - 1;
+
 	tegra_dc_writel(dc, h_offset, DC_WINBUF_ADDR_H_OFFSET);
 	tegra_dc_writel(dc, v_offset, DC_WINBUF_ADDR_V_OFFSET);
 
@@ -548,6 +569,9 @@ int tegra_dc_setup_window(struct tegra_dc *dc, unsigned int index,
 		value |= COLOR_EXPAND;
 	}
 
+	if (window->bottom_up)
+		value |= INVERT_V;
+
 	tegra_dc_writel(dc, value, DC_WIN_WIN_OPTIONS);
 
 	/*

drivers/gpu/drm/tegra/dc.h

@@ -302,6 +302,7 @@
 #define DC_WIN_CSC_KVB				0x618
 
 #define DC_WIN_WIN_OPTIONS			0x700
+#define INVERT_V     (1 <<  2)
 #define COLOR_EXPAND (1 <<  6)
 #define CSC_ENABLE   (1 << 18)
 #define WIN_ENABLE   (1 << 30)

drivers/gpu/drm/tegra/drm.h

@@ -148,6 +148,7 @@ struct tegra_dc_window {
 	unsigned int format;
 	unsigned int stride[2];
 	unsigned long base[3];
+	bool bottom_up;
 	bool tiled;
 };
 
@@ -255,6 +256,7 @@ extern int tegra_output_exit(struct tegra_output *output);
 /* from fb.c */
 struct tegra_bo *tegra_fb_get_plane(struct drm_framebuffer *framebuffer,
 				    unsigned int index);
+bool tegra_fb_is_bottom_up(struct drm_framebuffer *framebuffer);
 bool tegra_fb_is_tiled(struct drm_framebuffer *framebuffer);
 extern int tegra_drm_fb_init(struct drm_device *drm);
 extern void tegra_drm_fb_exit(struct drm_device *drm);

drivers/gpu/drm/tegra/fb.c

@@ -34,6 +34,16 @@ struct tegra_bo *tegra_fb_get_plane(struct drm_framebuffer *framebuffer,
 	return fb->planes[index];
 }
 
+bool tegra_fb_is_bottom_up(struct drm_framebuffer *framebuffer)
+{
+	struct tegra_fb *fb = to_tegra_fb(framebuffer);
+
+	if (fb->planes[0]->flags & TEGRA_BO_BOTTOM_UP)
+		return true;
+
+	return false;
+}
+
 bool tegra_fb_is_tiled(struct drm_framebuffer *framebuffer)
 {
 	struct tegra_fb *fb = to_tegra_fb(framebuffer);

drivers/gpu/drm/tegra/gem.c

@@ -132,6 +132,9 @@ struct tegra_bo *tegra_bo_create(struct drm_device *drm, unsigned int size,
 	if (flags & DRM_TEGRA_GEM_CREATE_TILED)
 		bo->flags |= TEGRA_BO_TILED;
 
+	if (flags & DRM_TEGRA_GEM_CREATE_BOTTOM_UP)
+		bo->flags |= TEGRA_BO_BOTTOM_UP;
+
 	return bo;
 
 err_mmap:

drivers/gpu/drm/tegra/gem.h

@@ -24,7 +24,8 @@
 #include <drm/drm.h>
 #include <drm/drmP.h>
 
-#define TEGRA_BO_TILED (1 << 0)
+#define TEGRA_BO_TILED     (1 << 0)
+#define TEGRA_BO_BOTTOM_UP (1 << 1)
 
 struct tegra_bo {
 	struct drm_gem_object gem;

include/uapi/drm/tegra_drm.h

@@ -19,7 +19,8 @@
 
 #include <drm/drm.h>
 
-#define DRM_TEGRA_GEM_CREATE_TILED (1 << 0)
+#define DRM_TEGRA_GEM_CREATE_TILED     (1 << 0)
+#define DRM_TEGRA_GEM_CREATE_BOTTOM_UP (1 << 1)
 
 struct drm_tegra_gem_create {
 	__u64 size;