1 /*
2  * drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
3  *
4  * Copyright (C) 2011 Texas Instruments
5  * Author: Rob Clark <rob.clark@linaro.org>
6  *
7  * This program is free software; you can redistribute it and/or modify it
8  * under the terms of the GNU General Public License version 2 as published by
9  * the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14  * more details.
15  *
16  * You should have received a copy of the GNU General Public License along with
17  * this program.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include <linux/dma-buf.h>
21 
22 #include "omap_drv.h"
23 
24 /* -----------------------------------------------------------------------------
25  * DMABUF Export
26  */
27 
28 static struct sg_table *omap_gem_map_dma_buf(
29 		struct dma_buf_attachment *attachment,
30 		enum dma_data_direction dir)
31 {
32 	struct drm_gem_object *obj = attachment->dmabuf->priv;
33 	struct sg_table *sg;
34 	dma_addr_t dma_addr;
35 	int ret;
36 
37 	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
38 	if (!sg)
39 		return ERR_PTR(-ENOMEM);
40 
41 	/* camera, etc, need physically contiguous.. but we need a
42 	 * better way to know this..
43 	 */
44 	ret = omap_gem_pin(obj, &dma_addr);
45 	if (ret)
46 		goto out;
47 
48 	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
49 	if (ret)
50 		goto out;
51 
52 	sg_init_table(sg->sgl, 1);
53 	sg_dma_len(sg->sgl) = obj->size;
54 	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
55 	sg_dma_address(sg->sgl) = dma_addr;
56 
57 	/* this must be after omap_gem_pin() to ensure we have pages attached */
58 	omap_gem_dma_sync_buffer(obj, dir);
59 
60 	return sg;
61 out:
62 	kfree(sg);
63 	return ERR_PTR(ret);
64 }
65 
66 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
67 		struct sg_table *sg, enum dma_data_direction dir)
68 {
69 	struct drm_gem_object *obj = attachment->dmabuf->priv;
70 	omap_gem_unpin(obj);
71 	sg_free_table(sg);
72 	kfree(sg);
73 }
74 
75 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
76 		enum dma_data_direction dir)
77 {
78 	struct drm_gem_object *obj = buffer->priv;
79 	struct page **pages;
80 	if (omap_gem_flags(obj) & OMAP_BO_TILED) {
81 		/* TODO we would need to pin at least part of the buffer to
82 		 * get de-tiled view.  For now just reject it.
83 		 */
84 		return -ENOMEM;
85 	}
86 	/* make sure we have the pages: */
87 	return omap_gem_get_pages(obj, &pages, true);
88 }
89 
90 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
91 					  enum dma_data_direction dir)
92 {
93 	struct drm_gem_object *obj = buffer->priv;
94 	omap_gem_put_pages(obj);
95 	return 0;
96 }
97 
98 
99 static void *omap_gem_dmabuf_kmap_atomic(struct dma_buf *buffer,
100 		unsigned long page_num)
101 {
102 	struct drm_gem_object *obj = buffer->priv;
103 	struct page **pages;
104 	omap_gem_get_pages(obj, &pages, false);
105 	omap_gem_cpu_sync_page(obj, page_num);
106 	return kmap_atomic(pages[page_num]);
107 }
108 
109 static void omap_gem_dmabuf_kunmap_atomic(struct dma_buf *buffer,
110 		unsigned long page_num, void *addr)
111 {
112 	kunmap_atomic(addr);
113 }
114 
115 static void *omap_gem_dmabuf_kmap(struct dma_buf *buffer,
116 		unsigned long page_num)
117 {
118 	struct drm_gem_object *obj = buffer->priv;
119 	struct page **pages;
120 	omap_gem_get_pages(obj, &pages, false);
121 	omap_gem_cpu_sync_page(obj, page_num);
122 	return kmap(pages[page_num]);
123 }
124 
125 static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
126 		unsigned long page_num, void *addr)
127 {
128 	struct drm_gem_object *obj = buffer->priv;
129 	struct page **pages;
130 	omap_gem_get_pages(obj, &pages, false);
131 	kunmap(pages[page_num]);
132 }
133 
134 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
135 		struct vm_area_struct *vma)
136 {
137 	struct drm_gem_object *obj = buffer->priv;
138 	int ret = 0;
139 
140 	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
141 	if (ret < 0)
142 		return ret;
143 
144 	return omap_gem_mmap_obj(obj, vma);
145 }
146 
147 static const struct dma_buf_ops omap_dmabuf_ops = {
148 	.map_dma_buf = omap_gem_map_dma_buf,
149 	.unmap_dma_buf = omap_gem_unmap_dma_buf,
150 	.release = drm_gem_dmabuf_release,
151 	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
152 	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
153 	.map_atomic = omap_gem_dmabuf_kmap_atomic,
154 	.unmap_atomic = omap_gem_dmabuf_kunmap_atomic,
155 	.map = omap_gem_dmabuf_kmap,
156 	.unmap = omap_gem_dmabuf_kunmap,
157 	.mmap = omap_gem_dmabuf_mmap,
158 };
159 
160 struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
161 		struct drm_gem_object *obj, int flags)
162 {
163 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
164 
165 	exp_info.ops = &omap_dmabuf_ops;
166 	exp_info.size = obj->size;
167 	exp_info.flags = flags;
168 	exp_info.priv = obj;
169 
170 	return drm_gem_dmabuf_export(dev, &exp_info);
171 }
172 
173 /* -----------------------------------------------------------------------------
174  * DMABUF Import
175  */
176 
177 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
178 					     struct dma_buf *dma_buf)
179 {
180 	struct dma_buf_attachment *attach;
181 	struct drm_gem_object *obj;
182 	struct sg_table *sgt;
183 	int ret;
184 
185 	if (dma_buf->ops == &omap_dmabuf_ops) {
186 		obj = dma_buf->priv;
187 		if (obj->dev == dev) {
188 			/*
189 			 * Importing dmabuf exported from out own gem increases
190 			 * refcount on gem itself instead of f_count of dmabuf.
191 			 */
192 			drm_gem_object_reference(obj);
193 			return obj;
194 		}
195 	}
196 
197 	attach = dma_buf_attach(dma_buf, dev->dev);
198 	if (IS_ERR(attach))
199 		return ERR_CAST(attach);
200 
201 	get_dma_buf(dma_buf);
202 
203 	sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
204 	if (IS_ERR(sgt)) {
205 		ret = PTR_ERR(sgt);
206 		goto fail_detach;
207 	}
208 
209 	obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
210 	if (IS_ERR(obj)) {
211 		ret = PTR_ERR(obj);
212 		goto fail_unmap;
213 	}
214 
215 	obj->import_attach = attach;
216 
217 	return obj;
218 
219 fail_unmap:
220 	dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
221 fail_detach:
222 	dma_buf_detach(dma_buf, attach);
223 	dma_buf_put(dma_buf);
224 
225 	return ERR_PTR(ret);
226 }
227