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