drm/ast: Allocate cursor BOs at high end of video memory

By putting cursor BOs at the high end of the video memory, we can avoid
memory fragmentation. Starting at the low end, contiguous video memory is
available for framebuffers.

The patch also simplifies the buffer swapping by splitting
struct ast_private.cursor_cache BO into two separate boffer objects. Cursor
images alternate between these buffers instead of offsets within cursor_cache.

v3:
	* fixes space-before-tab error near AST_HWC_SIGNATURE_CHECKSUM
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190927090309.10254-6-tzimmermann@suse.de

drivers/gpu/drm/ast/ast_drv.h

@@ -82,6 +82,25 @@ enum ast_tx_chip {
 #define AST_DRAM_4Gx16   7
 #define AST_DRAM_8Gx16   8
 
+
+#define AST_MAX_HWC_WIDTH	64
+#define AST_MAX_HWC_HEIGHT	64
+
+#define AST_HWC_SIZE		(AST_MAX_HWC_WIDTH * AST_MAX_HWC_HEIGHT * 2)
+#define AST_HWC_SIGNATURE_SIZE	32
+
+#define AST_DEFAULT_HWC_NUM	2
+
+/* define for signature structure */
+#define AST_HWC_SIGNATURE_CHECKSUM	0x00
+#define AST_HWC_SIGNATURE_SizeX		0x04
+#define AST_HWC_SIGNATURE_SizeY		0x08
+#define AST_HWC_SIGNATURE_X		0x0C
+#define AST_HWC_SIGNATURE_Y		0x10
+#define AST_HWC_SIGNATURE_HOTSPOTX	0x14
+#define AST_HWC_SIGNATURE_HOTSPOTY	0x18
+
+
 struct ast_private {
 	struct drm_device *dev;
 
@@ -97,8 +116,11 @@ struct ast_private {
 
 	int fb_mtrr;
 
-	struct drm_gem_object *cursor_cache;
-	int next_cursor;
+	struct {
+		struct drm_gem_vram_object *gbo[AST_DEFAULT_HWC_NUM];
+		unsigned int next_index;
+	} cursor;
+
 	bool support_wide_screen;
 	enum {
 		ast_use_p2a,
@@ -199,23 +221,6 @@ static inline void ast_open_key(struct ast_private *ast)
 
 #define AST_VIDMEM_DEFAULT_SIZE AST_VIDMEM_SIZE_8M
 
-#define AST_MAX_HWC_WIDTH 64
-#define AST_MAX_HWC_HEIGHT 64
-
-#define AST_HWC_SIZE                (AST_MAX_HWC_WIDTH*AST_MAX_HWC_HEIGHT*2)
-#define AST_HWC_SIGNATURE_SIZE      32
-
-#define AST_DEFAULT_HWC_NUM 2
-/* define for signature structure */
-#define AST_HWC_SIGNATURE_CHECKSUM  0x00
-#define AST_HWC_SIGNATURE_SizeX     0x04
-#define AST_HWC_SIGNATURE_SizeY     0x08
-#define AST_HWC_SIGNATURE_X         0x0C
-#define AST_HWC_SIGNATURE_Y         0x10
-#define AST_HWC_SIGNATURE_HOTSPOTX  0x14
-#define AST_HWC_SIGNATURE_HOTSPOTY  0x18
-
-
 struct ast_i2c_chan {
 	struct i2c_adapter adapter;
 	struct drm_device *dev;

drivers/gpu/drm/ast/ast_mode.c

@@ -883,50 +883,53 @@ static int ast_connector_init(struct drm_device *dev)
 static int ast_cursor_init(struct drm_device *dev)
 {
 	struct ast_private *ast = dev->dev_private;
-	int size;
-	int ret;
-	struct drm_gem_object *obj;
+	size_t size, i;
 	struct drm_gem_vram_object *gbo;
-	s64 gpu_addr;
-	void *base;
+	int ret;
 
-	size = (AST_HWC_SIZE + AST_HWC_SIGNATURE_SIZE) * AST_DEFAULT_HWC_NUM;
+	size = roundup(AST_HWC_SIZE + AST_HWC_SIGNATURE_SIZE, PAGE_SIZE);
 
-	ret = ast_gem_create(dev, size, true, &obj);
-	if (ret)
-		return ret;
-	gbo = drm_gem_vram_of_gem(obj);
-	ret = drm_gem_vram_pin(gbo, DRM_GEM_VRAM_PL_FLAG_VRAM);
-	if (ret)
-		goto fail;
-	gpu_addr = drm_gem_vram_offset(gbo);
-	if (gpu_addr < 0) {
-		drm_gem_vram_unpin(gbo);
-		ret = (int)gpu_addr;
-		goto fail;
-	}
+	for (i = 0; i < ARRAY_SIZE(ast->cursor.gbo); ++i) {
+		gbo = drm_gem_vram_create(dev, &dev->vram_mm->bdev,
+					  size, 0, false);
+		if (IS_ERR(gbo)) {
+			ret = PTR_ERR(gbo);
+			goto err_drm_gem_vram_put;
+		}
+		ret = drm_gem_vram_pin(gbo, DRM_GEM_VRAM_PL_FLAG_VRAM |
+					    DRM_GEM_VRAM_PL_FLAG_TOPDOWN);
+		if (ret) {
+			drm_gem_vram_put(gbo);
+			goto err_drm_gem_vram_put;
+		}
 
-	/* kmap the object */
-	base = drm_gem_vram_kmap(gbo, true, NULL);
-	if (IS_ERR(base)) {
-		ret = PTR_ERR(base);
-		goto fail;
+		ast->cursor.gbo[i] = gbo;
 	}
 
-	ast->cursor_cache = obj;
 	return 0;
-fail:
+
+err_drm_gem_vram_put:
+	while (i) {
+		--i;
+		gbo = ast->cursor.gbo[i];
+		drm_gem_vram_unpin(gbo);
+		drm_gem_vram_put(gbo);
+		ast->cursor.gbo[i] = NULL;
+	}
 	return ret;
 }
 
 static void ast_cursor_fini(struct drm_device *dev)
 {
 	struct ast_private *ast = dev->dev_private;
-	struct drm_gem_vram_object *gbo =
-		drm_gem_vram_of_gem(ast->cursor_cache);
-	drm_gem_vram_kunmap(gbo);
-	drm_gem_vram_unpin(gbo);
-	drm_gem_object_put_unlocked(ast->cursor_cache);
+	size_t i;
+	struct drm_gem_vram_object *gbo;
+
+	for (i = 0; i < ARRAY_SIZE(ast->cursor.gbo); ++i) {
+		gbo = ast->cursor.gbo[i];
+		drm_gem_vram_unpin(gbo);
+		drm_gem_vram_put(gbo);
+	}
 }
 
 int ast_mode_init(struct drm_device *dev)
@@ -1156,12 +1159,12 @@ static int ast_show_cursor(struct drm_crtc *crtc, void *src,
 	struct ast_private *ast = crtc->dev->dev_private;
 	struct ast_crtc *ast_crtc = to_ast_crtc(crtc);
 	struct drm_gem_vram_object *gbo;
-	u8 *dst, *dst_next;
+	void *dst;
 	s64 off;
 	int ret;
 	u8 jreg;
 
-	gbo = drm_gem_vram_of_gem(ast->cursor_cache);
+	gbo = ast->cursor.gbo[ast->cursor.next_index];
 	dst = drm_gem_vram_vmap(gbo);
 	if (IS_ERR(dst))
 		return PTR_ERR(dst);
@@ -1171,10 +1174,7 @@ static int ast_show_cursor(struct drm_crtc *crtc, void *src,
 		goto err_drm_gem_vram_vunmap;
 	}
 
-	dst_next = dst + (AST_HWC_SIZE + AST_HWC_SIGNATURE_SIZE) *
-		   ast->next_cursor;
-
-	ret = ast_cursor_update(dst_next, src, width, height);
+	ret = ast_cursor_update(dst, src, width, height);
 	if (ret)
 		goto err_drm_gem_vram_vunmap;
 	ast_cursor_set_base(ast, off);
@@ -1187,7 +1187,8 @@ static int ast_show_cursor(struct drm_crtc *crtc, void *src,
 	jreg |= 1;
 	ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xcb, 0xfc, jreg);
 
-	ast->next_cursor = (ast->next_cursor + 1) % AST_DEFAULT_HWC_NUM;
+	++ast->cursor.next_index;
+	ast->cursor.next_index %= ARRAY_SIZE(ast->cursor.gbo);
 
 	drm_gem_vram_vunmap(gbo, dst);
 
@@ -1257,13 +1258,17 @@ static int ast_cursor_move(struct drm_crtc *crtc,
 {
 	struct ast_crtc *ast_crtc = to_ast_crtc(crtc);
 	struct ast_private *ast = crtc->dev->dev_private;
+	struct drm_gem_vram_object *gbo;
 	int x_offset, y_offset;
-	u8 *sig;
+	u8 *dst, *sig;
 	u8 jreg;
 
-	sig = drm_gem_vram_kmap(drm_gem_vram_of_gem(ast->cursor_cache),
-				false, NULL);
-	sig += (AST_HWC_SIZE + AST_HWC_SIGNATURE_SIZE)*ast->next_cursor + AST_HWC_SIZE;
+	gbo = ast->cursor.gbo[ast->cursor.next_index];
+	dst = drm_gem_vram_vmap(gbo);
+	if (IS_ERR(dst))
+		return PTR_ERR(dst);
+
+	sig = dst + AST_HWC_SIZE;
 	writel(x, sig + AST_HWC_SIGNATURE_X);
 	writel(y, sig + AST_HWC_SIGNATURE_Y);
 
@@ -1290,5 +1295,7 @@ static int ast_cursor_move(struct drm_crtc *crtc,
 	       0x01; /* enable ARGB4444 cursor */
 	ast_set_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xcb, 0xfc, jreg);
 
+	drm_gem_vram_vunmap(gbo, dst);
+
 	return 0;
 }