tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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);
27 if (IS_ERR(sg))
28 return sg;
29
30 /* this must be after omap_gem_pin() to ensure we have pages attached */
31 omap_gem_dma_sync_buffer(obj, dir);
32
33 return sg;
34}
35
36static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
37 struct sg_table *sg, enum dma_data_direction dir)
38{
39 struct drm_gem_object *obj = attachment->dmabuf->priv;
40 omap_gem_put_sg(obj, sg);
41}
42
43static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
44 enum dma_data_direction dir)
45{
46 struct drm_gem_object *obj = buffer->priv;
47 struct page **pages;
48 if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
49 /* TODO we would need to pin at least part of the buffer to
50 * get de-tiled view. For now just reject it.
51 */
52 return -ENOMEM;
53 }
54 /* make sure we have the pages: */
55 return omap_gem_get_pages(obj, &pages, true);
56}
57
58static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
59 enum dma_data_direction dir)
60{
61 struct drm_gem_object *obj = buffer->priv;
62 omap_gem_put_pages(obj);
63 return 0;
64}
65
66static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
67 struct vm_area_struct *vma)
68{
69 struct drm_gem_object *obj = buffer->priv;
70 int ret = 0;
71
72 ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
73 if (ret < 0)
74 return ret;
75
76 return omap_gem_mmap_obj(obj, vma);
77}
78
79static const struct dma_buf_ops omap_dmabuf_ops = {
80 .map_dma_buf = omap_gem_map_dma_buf,
81 .unmap_dma_buf = omap_gem_unmap_dma_buf,
82 .release = drm_gem_dmabuf_release,
83 .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
84 .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
85 .mmap = omap_gem_dmabuf_mmap,
86};
87
88struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
89{
90 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
91
92 exp_info.ops = &omap_dmabuf_ops;
93 exp_info.size = omap_gem_mmap_size(obj);
94 exp_info.flags = flags;
95 exp_info.priv = obj;
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(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(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}