1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011 Texas Instruments Incorporated - http://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
14/* -----------------------------------------------------------------------------
15 * DMABUF Export
16 */
17
18static struct sg_table *omap_gem_map_dma_buf(
19		struct dma_buf_attachment *attachment,
20		enum dma_data_direction dir)
21{
22	struct drm_gem_object *obj = attachment->dmabuf->priv;
23	struct sg_table *sg;
24	dma_addr_t dma_addr;
25	int ret;
26
27	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
28	if (!sg)
29		return ERR_PTR(-ENOMEM);
30
31	/* camera, etc, need physically contiguous.. but we need a
32	 * better way to know this..
33	 */
34	ret = omap_gem_pin(obj, &dma_addr);
35	if (ret)
36		goto out;
37
38	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
39	if (ret)
40		goto out;
41
42	sg_init_table(sg->sgl, 1);
43	sg_dma_len(sg->sgl) = obj->size;
44	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
45	sg_dma_address(sg->sgl) = dma_addr;
46
47	/* this must be after omap_gem_pin() to ensure we have pages attached */
48	omap_gem_dma_sync_buffer(obj, dir);
49
50	return sg;
51out:
52	kfree(sg);
53	return ERR_PTR(ret);
54}
55
56static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
57		struct sg_table *sg, enum dma_data_direction dir)
58{
59	struct drm_gem_object *obj = attachment->dmabuf->priv;
60	omap_gem_unpin(obj);
61	sg_free_table(sg);
62	kfree(sg);
63}
64
65static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
66		enum dma_data_direction dir)
67{
68	struct drm_gem_object *obj = buffer->priv;
69	struct page **pages;
70	if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
71		/* TODO we would need to pin at least part of the buffer to
72		 * get de-tiled view.  For now just reject it.
73		 */
74		return -ENOMEM;
75	}
76	/* make sure we have the pages: */
77	return omap_gem_get_pages(obj, &pages, true);
78}
79
80static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
81					  enum dma_data_direction dir)
82{
83	struct drm_gem_object *obj = buffer->priv;
84	omap_gem_put_pages(obj);
85	return 0;
86}
87
88static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
89		struct vm_area_struct *vma)
90{
91	struct drm_gem_object *obj = buffer->priv;
92	int ret = 0;
93
94	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
95	if (ret < 0)
96		return ret;
97
98	return omap_gem_mmap_obj(obj, vma);
99}
100
101static const struct dma_buf_ops omap_dmabuf_ops = {
102	.map_dma_buf = omap_gem_map_dma_buf,
103	.unmap_dma_buf = omap_gem_unmap_dma_buf,
104	.release = drm_gem_dmabuf_release,
105	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
106	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
107	.mmap = omap_gem_dmabuf_mmap,
108};
109
110struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
111{
112	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
113
114	exp_info.ops = &omap_dmabuf_ops;
115	exp_info.size = obj->size;
116	exp_info.flags = flags;
117	exp_info.priv = obj;
118
119	return drm_gem_dmabuf_export(obj->dev, &exp_info);
120}
121
122/* -----------------------------------------------------------------------------
123 * DMABUF Import
124 */
125
126struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
127					     struct dma_buf *dma_buf)
128{
129	struct dma_buf_attachment *attach;
130	struct drm_gem_object *obj;
131	struct sg_table *sgt;
132	int ret;
133
134	if (dma_buf->ops == &omap_dmabuf_ops) {
135		obj = dma_buf->priv;
136		if (obj->dev == dev) {
137			/*
138			 * Importing dmabuf exported from out own gem increases
139			 * refcount on gem itself instead of f_count of dmabuf.
140			 */
141			drm_gem_object_get(obj);
142			return obj;
143		}
144	}
145
146	attach = dma_buf_attach(dma_buf, dev->dev);
147	if (IS_ERR(attach))
148		return ERR_CAST(attach);
149
150	get_dma_buf(dma_buf);
151
152	sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
153	if (IS_ERR(sgt)) {
154		ret = PTR_ERR(sgt);
155		goto fail_detach;
156	}
157
158	obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
159	if (IS_ERR(obj)) {
160		ret = PTR_ERR(obj);
161		goto fail_unmap;
162	}
163
164	obj->import_attach = attach;
165
166	return obj;
167
168fail_unmap:
169	dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
170fail_detach:
171	dma_buf_detach(dma_buf, attach);
172	dma_buf_put(dma_buf);
173
174	return ERR_PTR(ret);
175}
176