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 
68 	return drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
69 }
70 
71 static const struct dma_buf_ops omap_dmabuf_ops = {
72 	.map_dma_buf = omap_gem_map_dma_buf,
73 	.unmap_dma_buf = omap_gem_unmap_dma_buf,
74 	.release = drm_gem_dmabuf_release,
75 	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
76 	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
77 	.mmap = omap_gem_dmabuf_mmap,
78 };
79 
80 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
81 {
82 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
83 
84 	exp_info.ops = &omap_dmabuf_ops;
85 	exp_info.size = omap_gem_mmap_size(obj);
86 	exp_info.flags = flags;
87 	exp_info.priv = obj;
88 	exp_info.resv = obj->resv;
89 
90 	return drm_gem_dmabuf_export(obj->dev, &exp_info);
91 }
92 
93 /* -----------------------------------------------------------------------------
94  * DMABUF Import
95  */
96 
97 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
98 					     struct dma_buf *dma_buf)
99 {
100 	struct dma_buf_attachment *attach;
101 	struct drm_gem_object *obj;
102 	struct sg_table *sgt;
103 	int ret;
104 
105 	if (dma_buf->ops == &omap_dmabuf_ops) {
106 		obj = dma_buf->priv;
107 		if (obj->dev == dev) {
108 			/*
109 			 * Importing dmabuf exported from out own gem increases
110 			 * refcount on gem itself instead of f_count of dmabuf.
111 			 */
112 			drm_gem_object_get(obj);
113 			return obj;
114 		}
115 	}
116 
117 	attach = dma_buf_attach(dma_buf, dev->dev);
118 	if (IS_ERR(attach))
119 		return ERR_CAST(attach);
120 
121 	get_dma_buf(dma_buf);
122 
123 	sgt = dma_buf_map_attachment_unlocked(attach, DMA_TO_DEVICE);
124 	if (IS_ERR(sgt)) {
125 		ret = PTR_ERR(sgt);
126 		goto fail_detach;
127 	}
128 
129 	obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
130 	if (IS_ERR(obj)) {
131 		ret = PTR_ERR(obj);
132 		goto fail_unmap;
133 	}
134 
135 	obj->import_attach = attach;
136 
137 	return obj;
138 
139 fail_unmap:
140 	dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_TO_DEVICE);
141 fail_detach:
142 	dma_buf_detach(dma_buf, attach);
143 	dma_buf_put(dma_buf);
144 
145 	return ERR_PTR(ret);
146 }
147