drivers/gpu/drm/ttm/ttm_agp_backend.c

Source file repositories/reference/linux-study-clean/drivers/gpu/drm/ttm/ttm_agp_backend.c

File Facts

System
Linux kernel
Corpus path
drivers/gpu/drm/ttm/ttm_agp_backend.c
Extension
.c
Size
4000 bytes
Lines
146
Domain
Driver Families
Bucket
drivers/gpu
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct ttm_agp_backend {
	struct ttm_tt ttm;
	struct agp_memory *mem;
	struct agp_bridge_data *bridge;
};

int ttm_agp_bind(struct ttm_tt *ttm, struct ttm_resource *bo_mem)
{
	struct ttm_agp_backend *agp_be = container_of(ttm, struct ttm_agp_backend, ttm);
	struct page *dummy_read_page = ttm_glob.dummy_read_page;
	struct agp_memory *mem;
	int ret, cached = ttm->caching == ttm_cached;
	unsigned i;

	if (agp_be->mem)
		return 0;

	mem = agp_allocate_memory(agp_be->bridge, ttm->num_pages, AGP_USER_MEMORY);
	if (unlikely(mem == NULL))
		return -ENOMEM;

	mem->page_count = 0;
	for (i = 0; i < ttm->num_pages; i++) {
		struct page *page = ttm->pages[i];

		if (!page)
			page = dummy_read_page;

		mem->pages[mem->page_count++] = page;
	}
	agp_be->mem = mem;

	mem->is_flushed = 1;
	mem->type = (cached) ? AGP_USER_CACHED_MEMORY : AGP_USER_MEMORY;

	ret = agp_bind_memory(mem, bo_mem->start);
	if (ret)
		pr_err("AGP Bind memory failed\n");

	return ret;
}
EXPORT_SYMBOL(ttm_agp_bind);

void ttm_agp_unbind(struct ttm_tt *ttm)
{
	struct ttm_agp_backend *agp_be = container_of(ttm, struct ttm_agp_backend, ttm);

	if (agp_be->mem) {
		if (agp_be->mem->is_bound) {
			agp_unbind_memory(agp_be->mem);
			return;
		}
		agp_free_memory(agp_be->mem);
		agp_be->mem = NULL;
	}
}
EXPORT_SYMBOL(ttm_agp_unbind);

bool ttm_agp_is_bound(struct ttm_tt *ttm)
{
	struct ttm_agp_backend *agp_be = container_of(ttm, struct ttm_agp_backend, ttm);

	if (!ttm)
		return false;

	return (agp_be->mem != NULL);
}
EXPORT_SYMBOL(ttm_agp_is_bound);

void ttm_agp_destroy(struct ttm_tt *ttm)
{
	struct ttm_agp_backend *agp_be = container_of(ttm, struct ttm_agp_backend, ttm);

	if (agp_be->mem)
		ttm_agp_unbind(ttm);
	ttm_tt_fini(ttm);
	kfree(agp_be);
}
EXPORT_SYMBOL(ttm_agp_destroy);

struct ttm_tt *ttm_agp_tt_create(struct ttm_buffer_object *bo,
				 struct agp_bridge_data *bridge,
				 uint32_t page_flags)
{
	struct ttm_agp_backend *agp_be;

	agp_be = kmalloc_obj(*agp_be);
	if (!agp_be)
		return NULL;

Annotation

Implementation Notes