1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2011 Texas Instruments Incorporated - https://www.ti.com/
  4 * Author: Rob Clark <rob.clark@linaro.org>
  5 */
  6
  7#include <linux/dma-buf.h>
  8#include <linux/highmem.h>
  9
 10#include <drm/drm_prime.h>
 11
 12#include "omap_drv.h"
 13
 14MODULE_IMPORT_NS(DMA_BUF);
 15
 16/* -----------------------------------------------------------------------------
 17 * DMABUF Export
 18 */
 19
 20static struct sg_table *omap_gem_map_dma_buf(
 21		struct dma_buf_attachment *attachment,
 22		enum dma_data_direction dir)
 23{
 24	struct drm_gem_object *obj = attachment->dmabuf->priv;
 25	struct sg_table *sg;
 26	sg = omap_gem_get_sg(obj, dir);
 27	if (IS_ERR(sg))
 28		return sg;
 29
 30	return sg;
 31}
 32
 33static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
 34		struct sg_table *sg, enum dma_data_direction dir)
 35{
 36	struct drm_gem_object *obj = attachment->dmabuf->priv;
 37	omap_gem_put_sg(obj, sg);
 38}
 39
 40static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
 41		enum dma_data_direction dir)
 42{
 43	struct drm_gem_object *obj = buffer->priv;
 44	struct page **pages;
 45	if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
 46		/* TODO we would need to pin at least part of the buffer to
 47		 * get de-tiled view.  For now just reject it.
 48		 */
 49		return -ENOMEM;
 50	}
 51	/* make sure we have the pages: */
 52	return omap_gem_get_pages(obj, &pages, true);
 53}
 54
 55static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
 56					  enum dma_data_direction dir)
 57{
 58	struct drm_gem_object *obj = buffer->priv;
 59	omap_gem_put_pages(obj);
 60	return 0;
 61}
 62
 63static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
 64		struct vm_area_struct *vma)
 65{
 66	struct drm_gem_object *obj = buffer->priv;
 67	int ret = 0;
 68
 69	dma_resv_assert_held(buffer->resv);
 70
 71	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
 72	if (ret < 0)
 73		return ret;
 74
 75	return omap_gem_mmap_obj(obj, vma);
 76}
 77
 78static const struct dma_buf_ops omap_dmabuf_ops = {
 79	.map_dma_buf = omap_gem_map_dma_buf,
 80	.unmap_dma_buf = omap_gem_unmap_dma_buf,
 81	.release = drm_gem_dmabuf_release,
 82	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
 83	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
 84	.mmap = omap_gem_dmabuf_mmap,
 85};
 86
 87struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
 88{
 89	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 90
 91	exp_info.ops = &omap_dmabuf_ops;
 92	exp_info.size = omap_gem_mmap_size(obj);
 93	exp_info.flags = flags;
 94	exp_info.priv = obj;
 95	exp_info.resv = obj->resv;
 96
 97	return drm_gem_dmabuf_export(obj->dev, &exp_info);
 98}
 99
100/* -----------------------------------------------------------------------------
101 * DMABUF Import
102 */
103
104struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
105					     struct dma_buf *dma_buf)
106{
107	struct dma_buf_attachment *attach;
108	struct drm_gem_object *obj;
109	struct sg_table *sgt;
110	int ret;
111
112	if (dma_buf->ops == &omap_dmabuf_ops) {
113		obj = dma_buf->priv;
114		if (obj->dev == dev) {
115			/*
116			 * Importing dmabuf exported from out own gem increases
117			 * refcount on gem itself instead of f_count of dmabuf.
118			 */
119			drm_gem_object_get(obj);
120			return obj;
121		}
122	}
123
124	attach = dma_buf_attach(dma_buf, dev->dev);
125	if (IS_ERR(attach))
126		return ERR_CAST(attach);
127
128	get_dma_buf(dma_buf);
129
130	sgt = dma_buf_map_attachment_unlocked(attach, DMA_TO_DEVICE);
131	if (IS_ERR(sgt)) {
132		ret = PTR_ERR(sgt);
133		goto fail_detach;
134	}
135
136	obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
137	if (IS_ERR(obj)) {
138		ret = PTR_ERR(obj);
139		goto fail_unmap;
140	}
141
142	obj->import_attach = attach;
143
144	return obj;
145
146fail_unmap:
147	dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_TO_DEVICE);
148fail_detach:
149	dma_buf_detach(dma_buf, attach);
150	dma_buf_put(dma_buf);
151
152	return ERR_PTR(ret);
153}