drm/ttm: add ttm_sys_manager v3

Add a separate manager for the system domain and make function tables
mandatory.

v2: debug is still optional
v3: return void during init

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210430092508.60710-1-christian.koenig@amd.com

drivers/gpu/drm/ttm/Makefile

@@ -4,7 +4,7 @@
 
 ttm-y := ttm_tt.o ttm_bo.o ttm_bo_util.o ttm_bo_vm.o ttm_module.o \
 	ttm_execbuf_util.o ttm_range_manager.o ttm_resource.o ttm_pool.o \
-	ttm_device.o
+	ttm_device.o ttm_sys_manager.o
 ttm-$(CONFIG_AGP) += ttm_agp_backend.o
 
 obj-$(CONFIG_DRM_TTM) += ttm.o

drivers/gpu/drm/ttm/ttm_device.c

@@ -165,21 +165,6 @@ int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
 }
 EXPORT_SYMBOL(ttm_device_swapout);
 
-static void ttm_init_sysman(struct ttm_device *bdev)
-{
-	struct ttm_resource_manager *man = &bdev->sysman;
-
-	/*
-	 * Initialize the system memory buffer type.
-	 * Other types need to be driver / IOCTL initialized.
-	 */
-	man->use_tt = true;
-
-	ttm_resource_manager_init(man, 0);
-	ttm_set_driver_manager(bdev, TTM_PL_SYSTEM, man);
-	ttm_resource_manager_set_used(man, true);
-}
-
 static void ttm_device_delayed_workqueue(struct work_struct *work)
 {
 	struct ttm_device *bdev =
@@ -222,7 +207,7 @@ int ttm_device_init(struct ttm_device *bdev, struct ttm_device_funcs *funcs,
 
 	bdev->funcs = funcs;
 
-	ttm_init_sysman(bdev);
+	ttm_sys_man_init(bdev);
 	ttm_pool_init(&bdev->pool, dev, use_dma_alloc, use_dma32);
 
 	bdev->vma_manager = vma_manager;

drivers/gpu/drm/ttm/ttm_module.h

@@ -34,7 +34,10 @@
 #define TTM_PFX "[TTM] "
 
 struct dentry;
+struct ttm_device;
 
 extern struct dentry *ttm_debugfs_root;
 
+void ttm_sys_man_init(struct ttm_device *bdev);
+
 #endif /* _TTM_MODULE_H_ */

drivers/gpu/drm/ttm/ttm_resource.c

@@ -33,9 +33,6 @@ int ttm_resource_alloc(struct ttm_buffer_object *bo,
 		ttm_manager_type(bo->bdev, res->mem_type);
 
 	res->mm_node = NULL;
-	if (!man->func || !man->func->alloc)
-		return 0;
-
 	return man->func->alloc(man, bo, place, res);
 }
 
@@ -44,9 +41,7 @@ void ttm_resource_free(struct ttm_buffer_object *bo, struct ttm_resource *res)
 	struct ttm_resource_manager *man =
 		ttm_manager_type(bo->bdev, res->mem_type);
 
-	if (man->func && man->func->free)
-		man->func->free(man, res);
-
+	man->func->free(man, res);
 	res->mm_node = NULL;
 	res->mem_type = TTM_PL_SYSTEM;
 }
@@ -139,7 +134,7 @@ void ttm_resource_manager_debug(struct ttm_resource_manager *man,
 	drm_printf(p, "  use_type: %d\n", man->use_type);
 	drm_printf(p, "  use_tt: %d\n", man->use_tt);
 	drm_printf(p, "  size: %llu\n", man->size);
-	if (man->func && man->func->debug)
-		(*man->func->debug)(man, p);
+	if (man->func->debug)
+		man->func->debug(man, p);
 }
 EXPORT_SYMBOL(ttm_resource_manager_debug);

drivers/gpu/drm/ttm/ttm_sys_manager.c

@@ -0,0 +1,39 @@
+/* SPDX-License-Identifier: GPL-2.0 OR MIT */
+
+#include <drm/ttm/ttm_resource.h>
+#include <drm/ttm/ttm_device.h>
+#include <drm/ttm/ttm_placement.h>
+
+static int ttm_sys_man_alloc(struct ttm_resource_manager *man,
+			     struct ttm_buffer_object *bo,
+			     const struct ttm_place *place,
+			     struct ttm_resource *mem)
+{
+	return 0;
+}
+
+static void ttm_sys_man_free(struct ttm_resource_manager *man,
+			     struct ttm_resource *mem)
+{
+}
+
+static const struct ttm_resource_manager_func ttm_sys_manager_func = {
+	.alloc = ttm_sys_man_alloc,
+	.free = ttm_sys_man_free,
+};
+
+void ttm_sys_man_init(struct ttm_device *bdev)
+{
+	struct ttm_resource_manager *man = &bdev->sysman;
+
+	/*
+	 * Initialize the system memory buffer type.
+	 * Other types need to be driver / IOCTL initialized.
+	 */
+	man->use_tt = true;
+	man->func = &ttm_sys_manager_func;
+
+	ttm_resource_manager_init(man, 0);
+	ttm_set_driver_manager(bdev, TTM_PL_SYSTEM, man);
+	ttm_resource_manager_set_used(man, true);
+}