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 "omap_drv.h"
21 
22 #include <linux/dma-buf.h>
23 
24 static struct sg_table *omap_gem_map_dma_buf(
25 		struct dma_buf_attachment *attachment,
26 		enum dma_data_direction dir)
27 {
28 	struct drm_gem_object *obj = attachment->dmabuf->priv;
29 	struct sg_table *sg;
30 	dma_addr_t paddr;
31 	int ret;
32 
33 	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
34 	if (!sg)
35 		return ERR_PTR(-ENOMEM);
36 
37 	/* camera, etc, need physically contiguous.. but we need a
38 	 * better way to know this..
39 	 */
40 	ret = omap_gem_get_paddr(obj, &paddr, true);
41 	if (ret)
42 		goto out;
43 
44 	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
45 	if (ret)
46 		goto out;
47 
48 	sg_init_table(sg->sgl, 1);
49 	sg_dma_len(sg->sgl) = obj->size;
50 	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(paddr)), obj->size, 0);
51 	sg_dma_address(sg->sgl) = paddr;
52 
53 	/* this should be after _get_paddr() to ensure we have pages attached */
54 	omap_gem_dma_sync(obj, dir);
55 
56 	return sg;
57 out:
58 	kfree(sg);
59 	return ERR_PTR(ret);
60 }
61 
62 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
63 		struct sg_table *sg, enum dma_data_direction dir)
64 {
65 	struct drm_gem_object *obj = attachment->dmabuf->priv;
66 	omap_gem_put_paddr(obj);
67 	sg_free_table(sg);
68 	kfree(sg);
69 }
70 
71 static void omap_gem_dmabuf_release(struct dma_buf *buffer)
72 {
73 	struct drm_gem_object *obj = buffer->priv;
74 	/* release reference that was taken when dmabuf was exported
75 	 * in omap_gem_prime_set()..
76 	 */
77 	drm_gem_object_unreference_unlocked(obj);
78 }
79 
80 
81 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
82 		size_t start, size_t len, enum dma_data_direction dir)
83 {
84 	struct drm_gem_object *obj = buffer->priv;
85 	struct page **pages;
86 	if (omap_gem_flags(obj) & OMAP_BO_TILED) {
87 		/* TODO we would need to pin at least part of the buffer to
88 		 * get de-tiled view.  For now just reject it.
89 		 */
90 		return -ENOMEM;
91 	}
92 	/* make sure we have the pages: */
93 	return omap_gem_get_pages(obj, &pages, true);
94 }
95 
96 static void omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
97 		size_t start, size_t len, enum dma_data_direction dir)
98 {
99 	struct drm_gem_object *obj = buffer->priv;
100 	omap_gem_put_pages(obj);
101 }
102 
103 
104 static void *omap_gem_dmabuf_kmap_atomic(struct dma_buf *buffer,
105 		unsigned long page_num)
106 {
107 	struct drm_gem_object *obj = buffer->priv;
108 	struct page **pages;
109 	omap_gem_get_pages(obj, &pages, false);
110 	omap_gem_cpu_sync(obj, page_num);
111 	return kmap_atomic(pages[page_num]);
112 }
113 
114 static void omap_gem_dmabuf_kunmap_atomic(struct dma_buf *buffer,
115 		unsigned long page_num, void *addr)
116 {
117 	kunmap_atomic(addr);
118 }
119 
120 static void *omap_gem_dmabuf_kmap(struct dma_buf *buffer,
121 		unsigned long page_num)
122 {
123 	struct drm_gem_object *obj = buffer->priv;
124 	struct page **pages;
125 	omap_gem_get_pages(obj, &pages, false);
126 	omap_gem_cpu_sync(obj, page_num);
127 	return kmap(pages[page_num]);
128 }
129 
130 static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
131 		unsigned long page_num, void *addr)
132 {
133 	struct drm_gem_object *obj = buffer->priv;
134 	struct page **pages;
135 	omap_gem_get_pages(obj, &pages, false);
136 	kunmap(pages[page_num]);
137 }
138 
139 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
140 		struct vm_area_struct *vma)
141 {
142 	struct drm_gem_object *obj = buffer->priv;
143 	struct drm_device *dev = obj->dev;
144 	int ret = 0;
145 
146 	if (WARN_ON(!obj->filp))
147 		return -EINVAL;
148 
149 	mutex_lock(&dev->struct_mutex);
150 	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
151 	mutex_unlock(&dev->struct_mutex);
152 	if (ret < 0)
153 		return ret;
154 
155 	return omap_gem_mmap_obj(obj, vma);
156 }
157 
158 static struct dma_buf_ops omap_dmabuf_ops = {
159 	.map_dma_buf = omap_gem_map_dma_buf,
160 	.unmap_dma_buf = omap_gem_unmap_dma_buf,
161 	.release = omap_gem_dmabuf_release,
162 	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
163 	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
164 	.kmap_atomic = omap_gem_dmabuf_kmap_atomic,
165 	.kunmap_atomic = omap_gem_dmabuf_kunmap_atomic,
166 	.kmap = omap_gem_dmabuf_kmap,
167 	.kunmap = omap_gem_dmabuf_kunmap,
168 	.mmap = omap_gem_dmabuf_mmap,
169 };
170 
171 struct dma_buf *omap_gem_prime_export(struct drm_device *dev,
172 		struct drm_gem_object *obj, int flags)
173 {
174 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
175 
176 	exp_info.ops = &omap_dmabuf_ops;
177 	exp_info.size = obj->size;
178 	exp_info.flags = flags;
179 	exp_info.priv = obj;
180 
181 	return dma_buf_export(&exp_info);
182 }
183 
184 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
185 		struct dma_buf *buffer)
186 {
187 	struct drm_gem_object *obj;
188 
189 	/* is this one of own objects? */
190 	if (buffer->ops == &omap_dmabuf_ops) {
191 		obj = buffer->priv;
192 		/* is it from our device? */
193 		if (obj->dev == dev) {
194 			/*
195 			 * Importing dmabuf exported from out own gem increases
196 			 * refcount on gem itself instead of f_count of dmabuf.
197 			 */
198 			drm_gem_object_reference(obj);
199 			return obj;
200 		}
201 	}
202 
203 	/*
204 	 * TODO add support for importing buffers from other devices..
205 	 * for now we don't need this but would be nice to add eventually
206 	 */
207 	return ERR_PTR(-EINVAL);
208 }
209