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
14 MODULE_IMPORT_NS(DMA_BUF);
15
16 /* -----------------------------------------------------------------------------
17 * DMABUF Export
18 */
19
omap_gem_map_dma_buf(struct dma_buf_attachment * attachment,enum dma_data_direction dir)20 static 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
omap_gem_unmap_dma_buf(struct dma_buf_attachment * attachment,struct sg_table * sg,enum dma_data_direction dir)33 static 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
omap_gem_dmabuf_begin_cpu_access(struct dma_buf * buffer,enum dma_data_direction dir)40 static 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
omap_gem_dmabuf_end_cpu_access(struct dma_buf * buffer,enum dma_data_direction dir)55 static 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
omap_gem_dmabuf_mmap(struct dma_buf * buffer,struct vm_area_struct * vma)63 static 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
78 static 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
omap_gem_prime_export(struct drm_gem_object * obj,int flags)87 struct 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
omap_gem_prime_import(struct drm_device * dev,struct dma_buf * dma_buf)104 struct 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
146 fail_unmap:
147 dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_TO_DEVICE);
148 fail_detach:
149 dma_buf_detach(dma_buf, attach);
150 dma_buf_put(dma_buf);
151
152 return ERR_PTR(ret);
153 }
154