linux/include/drm/drm_gem_vram_helper.h
Thomas Zimmermann 37a48adfba drm/vram: Add kmap ref-counting to GEM VRAM objects
The kmap and kunmap operations of GEM VRAM buffers can now be called
in interleaving pairs. The first call to drm_gem_vram_kmap() maps the
buffer's memory to kernel address space and the final call to
drm_gem_vram_kunmap() unmaps the memory. Intermediate calls to these
functions increment or decrement a reference counter.

This change allows for keeping buffer memory mapped for longer and
minimizes the amount of changes to TLB, page tables, etc.

v4:
	* lock in kmap()/kunmap() with ttm_bo_reserve()

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reported-and-tested-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190906122056.32018-2-tzimmermann@suse.de
2019-09-09 12:51:31 +02:00

144 lines
4.2 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
#ifndef DRM_GEM_VRAM_HELPER_H
#define DRM_GEM_VRAM_HELPER_H
#include <drm/drm_gem.h>
#include <drm/ttm/ttm_bo_api.h>
#include <drm/ttm/ttm_placement.h>
#include <linux/kernel.h> /* for container_of() */
struct drm_mode_create_dumb;
struct drm_vram_mm_funcs;
struct filp;
struct vm_area_struct;
#define DRM_GEM_VRAM_PL_FLAG_VRAM TTM_PL_FLAG_VRAM
#define DRM_GEM_VRAM_PL_FLAG_SYSTEM TTM_PL_FLAG_SYSTEM
/*
* Buffer-object helpers
*/
/**
* struct drm_gem_vram_object - GEM object backed by VRAM
* @gem: GEM object
* @bo: TTM buffer object
* @kmap: Mapping information for @bo
* @placement: TTM placement information. Supported placements are \
%TTM_PL_VRAM and %TTM_PL_SYSTEM
* @placements: TTM placement information.
* @pin_count: Pin counter
*
* The type struct drm_gem_vram_object represents a GEM object that is
* backed by VRAM. It can be used for simple framebuffer devices with
* dedicated memory. The buffer object can be evicted to system memory if
* video memory becomes scarce.
*
* GEM VRAM objects perform reference counting for pin and mapping
* operations. So a buffer object that has been pinned N times with
* drm_gem_vram_pin() must be unpinned N times with
* drm_gem_vram_unpin(). The same applies to pairs of
* drm_gem_vram_kmap() and drm_gem_vram_kunmap().
*/
struct drm_gem_vram_object {
struct ttm_buffer_object bo;
struct ttm_bo_kmap_obj kmap;
/**
* @kmap_use_count:
*
* Reference count on the virtual address.
* The address are un-mapped when the count reaches zero.
*/
unsigned int kmap_use_count;
/* Supported placements are %TTM_PL_VRAM and %TTM_PL_SYSTEM */
struct ttm_placement placement;
struct ttm_place placements[2];
int pin_count;
};
/**
* Returns the container of type &struct drm_gem_vram_object
* for field bo.
* @bo: the VRAM buffer object
* Returns: The containing GEM VRAM object
*/
static inline struct drm_gem_vram_object *drm_gem_vram_of_bo(
struct ttm_buffer_object *bo)
{
return container_of(bo, struct drm_gem_vram_object, bo);
}
/**
* Returns the container of type &struct drm_gem_vram_object
* for field gem.
* @gem: the GEM object
* Returns: The containing GEM VRAM object
*/
static inline struct drm_gem_vram_object *drm_gem_vram_of_gem(
struct drm_gem_object *gem)
{
return container_of(gem, struct drm_gem_vram_object, bo.base);
}
struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
struct ttm_bo_device *bdev,
size_t size,
unsigned long pg_align,
bool interruptible);
void drm_gem_vram_put(struct drm_gem_vram_object *gbo);
u64 drm_gem_vram_mmap_offset(struct drm_gem_vram_object *gbo);
s64 drm_gem_vram_offset(struct drm_gem_vram_object *gbo);
int drm_gem_vram_pin(struct drm_gem_vram_object *gbo, unsigned long pl_flag);
int drm_gem_vram_unpin(struct drm_gem_vram_object *gbo);
void *drm_gem_vram_kmap(struct drm_gem_vram_object *gbo, bool map,
bool *is_iomem);
void drm_gem_vram_kunmap(struct drm_gem_vram_object *gbo);
int drm_gem_vram_fill_create_dumb(struct drm_file *file,
struct drm_device *dev,
struct ttm_bo_device *bdev,
unsigned long pg_align,
bool interruptible,
struct drm_mode_create_dumb *args);
/*
* Helpers for struct ttm_bo_driver
*/
void drm_gem_vram_bo_driver_evict_flags(struct ttm_buffer_object *bo,
struct ttm_placement *pl);
int drm_gem_vram_bo_driver_verify_access(struct ttm_buffer_object *bo,
struct file *filp);
extern const struct drm_vram_mm_funcs drm_gem_vram_mm_funcs;
/*
* Helpers for struct drm_driver
*/
int drm_gem_vram_driver_dumb_create(struct drm_file *file,
struct drm_device *dev,
struct drm_mode_create_dumb *args);
int drm_gem_vram_driver_dumb_mmap_offset(struct drm_file *file,
struct drm_device *dev,
uint32_t handle, uint64_t *offset);
/**
* define DRM_GEM_VRAM_DRIVER - default callback functions for \
&struct drm_driver
*
* Drivers that use VRAM MM and GEM VRAM can use this macro to initialize
* &struct drm_driver with default functions.
*/
#define DRM_GEM_VRAM_DRIVER \
.dumb_create = drm_gem_vram_driver_dumb_create, \
.dumb_map_offset = drm_gem_vram_driver_dumb_mmap_offset, \
.gem_prime_mmap = drm_gem_prime_mmap
#endif