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 /* -----------------------------------------------------------------------------
15  * DMABUF Export
16  */
17 
18 static struct sg_table *omap_gem_map_dma_buf(
19 		struct dma_buf_attachment *attachment,
20 		enum dma_data_direction dir)
21 {
22 	struct drm_gem_object *obj = attachment->dmabuf->priv;
23 	struct sg_table *sg;
24 	dma_addr_t dma_addr;
25 	int ret;
26 
27 	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
28 	if (!sg)
29 		return ERR_PTR(-ENOMEM);
30 
31 	/* camera, etc, need physically contiguous.. but we need a
32 	 * better way to know this..
33 	 */
34 	ret = omap_gem_pin(obj, &dma_addr);
35 	if (ret)
36 		goto out;
37 
38 	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
39 	if (ret)
40 		goto out;
41 
42 	sg_init_table(sg->sgl, 1);
43 	sg_dma_len(sg->sgl) = obj->size;
44 	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
45 	sg_dma_address(sg->sgl) = dma_addr;
46 
47 	/* this must be after omap_gem_pin() to ensure we have pages attached */
48 	omap_gem_dma_sync_buffer(obj, dir);
49 
50 	return sg;
51 out:
52 	kfree(sg);
53 	return ERR_PTR(ret);
54 }
55 
56 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
57 		struct sg_table *sg, enum dma_data_direction dir)
58 {
59 	struct drm_gem_object *obj = attachment->dmabuf->priv;
60 	omap_gem_unpin(obj);
61 	sg_free_table(sg);
62 	kfree(sg);
63 }
64 
65 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
66 		enum dma_data_direction dir)
67 {
68 	struct drm_gem_object *obj = buffer->priv;
69 	struct page **pages;
70 	if (omap_gem_flags(obj) & OMAP_BO_TILED_MASK) {
71 		/* TODO we would need to pin at least part of the buffer to
72 		 * get de-tiled view.  For now just reject it.
73 		 */
74 		return -ENOMEM;
75 	}
76 	/* make sure we have the pages: */
77 	return omap_gem_get_pages(obj, &pages, true);
78 }
79 
80 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
81 					  enum dma_data_direction dir)
82 {
83 	struct drm_gem_object *obj = buffer->priv;
84 	omap_gem_put_pages(obj);
85 	return 0;
86 }
87 
88 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
89 		struct vm_area_struct *vma)
90 {
91 	struct drm_gem_object *obj = buffer->priv;
92 	int ret = 0;
93 
94 	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
95 	if (ret < 0)
96 		return ret;
97 
98 	return omap_gem_mmap_obj(obj, vma);
99 }
100 
101 static const struct dma_buf_ops omap_dmabuf_ops = {
102 	.map_dma_buf = omap_gem_map_dma_buf,
103 	.unmap_dma_buf = omap_gem_unmap_dma_buf,
104 	.release = drm_gem_dmabuf_release,
105 	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
106 	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
107 	.mmap = omap_gem_dmabuf_mmap,
108 };
109 
110 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
111 {
112 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
113 
114 	exp_info.ops = &omap_dmabuf_ops;
115 	exp_info.size = obj->size;
116 	exp_info.flags = flags;
117 	exp_info.priv = obj;
118 
119 	return drm_gem_dmabuf_export(obj->dev, &exp_info);
120 }
121 
122 /* -----------------------------------------------------------------------------
123  * DMABUF Import
124  */
125 
126 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
127 					     struct dma_buf *dma_buf)
128 {
129 	struct dma_buf_attachment *attach;
130 	struct drm_gem_object *obj;
131 	struct sg_table *sgt;
132 	int ret;
133 
134 	if (dma_buf->ops == &omap_dmabuf_ops) {
135 		obj = dma_buf->priv;
136 		if (obj->dev == dev) {
137 			/*
138 			 * Importing dmabuf exported from out own gem increases
139 			 * refcount on gem itself instead of f_count of dmabuf.
140 			 */
141 			drm_gem_object_get(obj);
142 			return obj;
143 		}
144 	}
145 
146 	attach = dma_buf_attach(dma_buf, dev->dev);
147 	if (IS_ERR(attach))
148 		return ERR_CAST(attach);
149 
150 	get_dma_buf(dma_buf);
151 
152 	sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
153 	if (IS_ERR(sgt)) {
154 		ret = PTR_ERR(sgt);
155 		goto fail_detach;
156 	}
157 
158 	obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
159 	if (IS_ERR(obj)) {
160 		ret = PTR_ERR(obj);
161 		goto fail_unmap;
162 	}
163 
164 	obj->import_attach = attach;
165 
166 	return obj;
167 
168 fail_unmap:
169 	dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
170 fail_detach:
171 	dma_buf_detach(dma_buf, attach);
172 	dma_buf_put(dma_buf);
173 
174 	return ERR_PTR(ret);
175 }
176