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 
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 
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 
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 
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 
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 
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 
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_unlocked(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_unlocked(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