char/agp: Remove frontend code

The AGP subsystem supports a user-space interface via /dev/agpgart. It
is only enabled with DRM support for mode setting in user space. (i.e.,
CONFIG_DRM_LEGACY). All of that DRM code has been removed and the option
will go away. Hence remove the AGP frontend.

Modern DRM drivers with kernel mode setting handle AGP support internally.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: David Airlie <airlied@gmail.com>
Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231122122449.11588-14-tzimmermann@suse.de

drivers/char/agp/Makefile

@@ -1,12 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 agpgart-y := backend.o generic.o isoch.o
 
-ifeq ($(CONFIG_DRM_LEGACY),y)
-agpgart-$(CONFIG_COMPAT)	+= compat_ioctl.o
-agpgart-y			+= frontend.o
-endif
-
-
 obj-$(CONFIG_AGP)		+= agpgart.o
 obj-$(CONFIG_AGP_ALI)		+= ali-agp.o
 obj-$(CONFIG_AGP_ATI)		+= ati-agp.o

drivers/char/agp/agp.h

@@ -185,15 +185,6 @@ void agp_put_bridge(struct agp_bridge_data *bridge);
 int agp_add_bridge(struct agp_bridge_data *bridge);
 void agp_remove_bridge(struct agp_bridge_data *bridge);
 
-/* Frontend routines. */
-#if IS_ENABLED(CONFIG_DRM_LEGACY)
-int agp_frontend_initialize(void);
-void agp_frontend_cleanup(void);
-#else
-static inline int agp_frontend_initialize(void) { return 0; }
-static inline void agp_frontend_cleanup(void) {}
-#endif
-
 /* Generic routines. */
 void agp_generic_enable(struct agp_bridge_data *bridge, u32 mode);
 int agp_generic_create_gatt_table(struct agp_bridge_data *bridge);

drivers/char/agp/backend.c

@@ -293,13 +293,6 @@ int agp_add_bridge(struct agp_bridge_data *bridge)
 	}
 
 	if (list_empty(&agp_bridges)) {
-		error = agp_frontend_initialize();
-		if (error) {
-			dev_info(&bridge->dev->dev,
-				 "agp_frontend_initialize() failed\n");
-			goto frontend_err;
-		}
-
 		dev_info(&bridge->dev->dev, "AGP aperture is %dM @ 0x%lx\n",
 			 bridge->driver->fetch_size(), bridge->gart_bus_addr);
 
@@ -308,8 +301,6 @@ int agp_add_bridge(struct agp_bridge_data *bridge)
 	list_add(&bridge->list, &agp_bridges);
 	return 0;
 
-frontend_err:
-	agp_backend_cleanup(bridge);
 err_out:
 	module_put(bridge->driver->owner);
 err_put_bridge:
@@ -323,8 +314,6 @@ void agp_remove_bridge(struct agp_bridge_data *bridge)
 {
 	agp_backend_cleanup(bridge);
 	list_del(&bridge->list);
-	if (list_empty(&agp_bridges))
-		agp_frontend_cleanup();
 	module_put(bridge->driver->owner);
 }
 EXPORT_SYMBOL_GPL(agp_remove_bridge);