gem.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * NVIDIA Tegra DRM GEM helper functions
 *
 * Copyright (C) 2012 Sascha Hauer, Pengutronix
 * Copyright (C) 2013-2015 NVIDIA CORPORATION, All rights reserved.
 *
 * Based on the GEM/CMA helpers
 *
 * Copyright (c) 2011 Samsung Electronics Co., Ltd.
 */

#include <linux/dma-buf.h>
#include <linux/iommu.h>
#include <linux/module.h>

#include <drm/drm_drv.h>
#include <drm/drm_prime.h>
#include <drm/tegra_drm.h>

#include "drm.h"
#include "gem.h"

MODULE_IMPORT_NS(DMA_BUF);

static unsigned int sg_dma_count_chunks(struct scatterlist *sgl, unsigned int nents)
{
	dma_addr_t next = ~(dma_addr_t)0;
	unsigned int count = 0, i;
	struct scatterlist *s;

	for_each_sg(sgl, s, nents, i) {
		/* sg_dma_address(s) is only valid for entries that have sg_dma_len(s) != 0. */
		if (!sg_dma_len(s))
			continue;

		if (sg_dma_address(s) != next) {
			next = sg_dma_address(s) + sg_dma_len(s);
			count++;
		}
	}

	return count;
}

static inline unsigned int sgt_dma_count_chunks(struct sg_table *sgt)
{
	return sg_dma_count_chunks(sgt->sgl, sgt->nents);
}

static void tegra_bo_put(struct host1x_bo *bo)
{
	struct tegra_bo *obj = host1x_to_tegra_bo(bo);

	drm_gem_object_put(&obj->gem);
}

static struct host1x_bo_mapping *tegra_bo_pin(struct device *dev, struct host1x_bo *bo,
					      enum dma_data_direction direction)
{
	struct tegra_bo *obj = host1x_to_tegra_bo(bo);
	struct drm_gem_object *gem = &obj->gem;
	struct host1x_bo_mapping *map;
	int err;

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

	kref_init(&map->ref);