path: root/drivers/gpu/drm/drm_gem_vram_helper.c

// SPDX-License-Identifier: GPL-2.0-or-later

#include <drm/drm_debugfs.h>
#include <drm/drm_device.h>
#include <drm/drm_file.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_gem_ttm_helper.h>
#include <drm/drm_gem_vram_helper.h>
#include <drm/drm_mode.h>
#include <drm/drm_plane.h>
#include <drm/drm_prime.h>
#include <drm/drm_simple_kms_helper.h>
#include <drm/ttm/ttm_page_alloc.h>

static const struct drm_gem_object_funcs drm_gem_vram_object_funcs;

/**
 * DOC: overview
 *
 * This library provides a GEM buffer object that is backed by video RAM
 * (VRAM). It can be used for framebuffer devices with dedicated memory.
 *
 * The data structure &struct drm_vram_mm and its helpers implement a memory
 * manager for simple framebuffer devices with dedicated video memory. Buffer
 * objects are either placed in video RAM or evicted to system memory. The rsp.
 * buffer object is provided by &struct drm_gem_vram_object.
 */

/*
 * Buffer-objects helpers
 */

static void drm_gem_vram_cleanup(struct drm_gem_vram_object *gbo)
{
	/* We got here via ttm_bo_put(), which means that the
	 * TTM buffer object in 'bo' has already been cleaned
	 * up; only release the GEM object.
	 */

	WARN_ON(gbo->kmap_use_count);
	WARN_ON(gbo->kmap.virtual);

	drm_gem_object_release(&gbo->bo.base);
}

static void drm_gem_vram_destroy(struct drm_gem_vram_object *gbo)
{
	drm_gem_vram_cleanup(gbo);
	kfree(gbo);
}

static void ttm_buffer_object_destroy(struct ttm_buffer_object *bo)
{
	struct drm_gem_vram_object *gbo = drm_gem_vram_of_bo(bo);

	drm_gem_vram_destroy(gbo);
}

static void drm_gem_vram_placement(struct drm_gem_vram_object *gbo,
				   unsigned long pl_flag)
{
	unsigned int i;
	unsigned int c = 0;
	u32 invariant_flags = pl_flag & TTM_PL_FLAG_TOPDOWN;

	gbo->placement.placement = gbo->placements;
	gbo->placement.busy_placement = gbo->placements;

	if (pl_flag & TTM_PL_FLAG_VRAM)
		gbo->placements[c++].flags = TTM_PL_FLAG_WC |
					     TTM_PL_FLAG_UNCACHED |
					     TTM_PL_FLAG_VRAM |
					     invariant_flags;

	if (pl_flag & TTM_PL_FLAG_SYSTEM)
		gbo->placements[c++].flags = TTM_PL_MASK_CACHING |
					     TTM_PL_FLAG_SYSTEM |
					     invariant_flags;

	if (!c)
		gbo->placements[c++].flags = TTM_PL_MASK_CACHING |
					     TTM_PL_FLAG_SYSTEM |
					     invariant_flags;

	gbo->placement.num_placement = c;
	gbo->placement.num_busy_placement = c;

	for (i = 0; i < c; ++i) {
		gbo->placements[i].fpfn = 0;
		gbo->placements[i].lpfn = 0;
	}
}

static int drm_gem_vram_init(struct drm_device *dev,
			     struct ttm_bo_device *bdev,
			     struct drm_gem_vram_object *gbo,
			     size_t size, unsigned long pg_align,
			     bool interruptible)
{
	int ret;
	size_t acc_size;

	gbo->bo.base.funcs = &drm_gem_vram_object_funcs;

	ret = drm_gem_object_init(dev, &gbo->bo.base, size);
	if (ret)
		return ret;

	acc_size = ttm_bo_dma_acc_size(bdev, size, sizeof(*gbo));

	gbo->bo.bdev = bdev;
	drm_gem_vram_placement(gbo, TTM_PL_FLAG_VRAM | TTM_PL_FLAG_SYSTEM);

	ret = ttm_bo_init(bdev, &gbo->bo, size, ttm_bo_type_device,
			  &gbo->placement, pg_align, interruptible, acc_size,
			  NULL, NULL, ttm_buffer_object_destroy);
	if (ret)
		goto err_drm_gem_object_release;

	return 0;

err_drm_gem_object_release:
	drm_gem_object_release(&gbo->bo.base);
	return ret;
}

/**
 * drm_gem_vram_create() - Creates a VRAM-backed GEM object
 * @dev:		the DRM device
 * @bdev:		the TTM BO device backing the object
 * @size:		the buffer size in bytes
 * @pg_align:		the buffer's alignment in multiples of the page size
 * @interruptible:	sleep interruptible if waiting for memory
 *
 * Returns:
 * A new instance of &struct drm_gem_vram_object on success, or
 * an ERR_PTR()-encoded error code otherwise.
 */
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)
{
	struct drm_gem_vram_object *gbo;
	int ret;

	gbo = kzalloc(sizeof(*gbo), GFP_KERNEL);
	if (!gbo)
		return ERR_PTR(-ENOMEM);

	ret = drm_gem_vram_init(dev, bdev, gbo, size, pg_align, interruptible);
	if (ret < 0)
		goto err_kfree;

	return gbo;

err_kfree:
	kfree(gbo);
	return ERR_PTR(ret);
}
EXPORT_SYMBOL(drm_gem_vram_create);

/*