drm/ast: Remove vram_fb_available from struct ast_device

Helpers compute the offset and size of the available framebuffer
memory. Remove the obsolete field vram_fb_available from struct
ast_device. Also define the cursor-signature size next to its only
user.

v2:
- initialize plane size

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250305163207.267650-7-tzimmermann@suse.de

3 files changed, 4 insertions, 19 deletions

diff --git a/drivers/gpu/drm/ast/ast_cursor.c b/drivers/gpu/drm/ast/ast_cursor.c
index 05e297f30b4e..cb0c48d47207 100644
--- a/drivers/gpu/drm/ast/ast_cursor.c
+++ b/drivers/gpu/drm/ast/ast_cursor.c
@@ -37,6 +37,7 @@
  */
 
 /* define for signature structure */
+#define AST_HWC_SIGNATURE_SIZE		SZ_32
 #define AST_HWC_SIGNATURE_CHECKSUM	0x00
 #define AST_HWC_SIGNATURE_SizeX		0x04
 #define AST_HWC_SIGNATURE_SizeY		0x08
@@ -289,25 +290,16 @@ int ast_cursor_plane_init(struct ast_device *ast)
 	struct ast_cursor_plane *ast_cursor_plane = &ast->cursor_plane;
 	struct ast_plane *ast_plane = &ast_cursor_plane->base;
 	struct drm_plane *cursor_plane = &ast_plane->base;
-	size_t size;
+	unsigned long size;
 	void __iomem *vaddr;
 	long offset;
 	int ret;
 
-	/*
-	 * Allocate backing storage for cursors. The BOs are permanently
-	 * pinned to the top end of the VRAM.
-	 */
-
-	size = roundup(AST_HWC_SIZE + AST_HWC_SIGNATURE_SIZE, PAGE_SIZE);
-
-	if (ast->vram_fb_available < size)
-		return -ENOMEM;
-
-	vaddr = ast->vram + ast->vram_fb_available - size;
+	size = ast_cursor_vram_size();
 	offset = ast_cursor_vram_offset(ast);
 	if (offset < 0)
 		return offset;
+	vaddr = ast->vram + offset;
 
 	ret = ast_plane_init(dev, ast_plane, vaddr, offset, size,
 			     0x01, &ast_cursor_plane_funcs,
@@ -320,7 +312,5 @@ int ast_cursor_plane_init(struct ast_device *ast)
 	drm_plane_helper_add(cursor_plane, &ast_cursor_plane_helper_funcs);
 	drm_plane_enable_fb_damage_clips(cursor_plane);
 
-	ast->vram_fb_available -= size;
-
 	return 0;
 }
diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index ec9ec77260e9..d9da2328d46b 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -112,12 +112,9 @@ enum ast_config_mode {
 
 #define AST_MAX_HWC_WIDTH	64
 #define AST_MAX_HWC_HEIGHT	64
-
 #define AST_HWC_PITCH		(AST_MAX_HWC_WIDTH * SZ_2)
 #define AST_HWC_SIZE		(AST_MAX_HWC_HEIGHT * AST_HWC_PITCH)
 
-#define AST_HWC_SIGNATURE_SIZE	32
-
 /*
  * Planes
  */
@@ -183,7 +180,6 @@ struct ast_device {
 	void __iomem	*vram;
 	unsigned long	vram_base;
 	unsigned long	vram_size;
-	unsigned long	vram_fb_available;
 
 	struct mutex modeset_lock; /* Protects access to modeset I/O registers in ioregs */
 
diff --git a/drivers/gpu/drm/ast/ast_mm.c b/drivers/gpu/drm/ast/ast_mm.c
index 3d03ef556d0a..0bc140319464 100644
--- a/drivers/gpu/drm/ast/ast_mm.c
+++ b/drivers/gpu/drm/ast/ast_mm.c
@@ -92,7 +92,6 @@ int ast_mm_init(struct ast_device *ast)
 
 	ast->vram_base = base;
 	ast->vram_size = vram_size;
-	ast->vram_fb_available = vram_size;
 
 	return 0;
 }