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 ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
70 if (ret < 0)
71 return ret;
72
73 return omap_gem_mmap_obj(obj, vma);
74 }
75
76 static const struct dma_buf_ops omap_dmabuf_ops = {
77 .map_dma_buf = omap_gem_map_dma_buf,
78 .unmap_dma_buf = omap_gem_unmap_dma_buf,
79 .release = drm_gem_dmabuf_release,
80 .begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
81 .end_cpu_access = omap_gem_dmabuf_end_cpu_access,
82 .mmap = omap_gem_dmabuf_mmap,
83 };
84
omap_gem_prime_export(struct drm_gem_object * obj,int flags)85 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
86 {
87 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
88
89 exp_info.ops = &omap_dmabuf_ops;
90 exp_info.size = omap_gem_mmap_size(obj);
91 exp_info.flags = flags;
92 exp_info.priv = obj;
93 exp_info.resv = obj->resv;
94
95 return drm_gem_dmabuf_export(obj->dev, &exp_info);
96 }
97
98 /* -----------------------------------------------------------------------------
99 * DMABUF Import
100 */
101
omap_gem_prime_import(struct drm_device * dev,struct dma_buf * dma_buf)102 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
103 struct dma_buf *dma_buf)
104 {
105 struct dma_buf_attachment *attach;
106 struct drm_gem_object *obj;
107 struct sg_table *sgt;
108 int ret;
109
110 if (dma_buf->ops == &omap_dmabuf_ops) {
111 obj = dma_buf->priv;
112 if (obj->dev == dev) {
113 /*
114 * Importing dmabuf exported from out own gem increases
115 * refcount on gem itself instead of f_count of dmabuf.
116 */
117 drm_gem_object_get(obj);
118 return obj;
119 }
120 }
121
122 attach = dma_buf_attach(dma_buf, dev->dev);
123 if (IS_ERR(attach))
124 return ERR_CAST(attach);
125
126 get_dma_buf(dma_buf);
127
128 sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
129 if (IS_ERR(sgt)) {
130 ret = PTR_ERR(sgt);
131 goto fail_detach;
132 }
133
134 obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
135 if (IS_ERR(obj)) {
136 ret = PTR_ERR(obj);
137 goto fail_unmap;
138 }
139
140 obj->import_attach = attach;
141
142 return obj;
143
144 fail_unmap:
145 dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
146 fail_detach:
147 dma_buf_detach(dma_buf, attach);
148 dma_buf_put(dma_buf);
149
150 return ERR_PTR(ret);
151 }
152
