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 #include <linux/highmem.h>
20 
21 #include <drm/drm_prime.h>
22 
23 #include "omap_drv.h"
24 
25 /* -----------------------------------------------------------------------------
26  * DMABUF Export
27  */
28 
29 static struct sg_table *omap_gem_map_dma_buf(
30 		struct dma_buf_attachment *attachment,
31 		enum dma_data_direction dir)
32 {
33 	struct drm_gem_object *obj = attachment->dmabuf->priv;
34 	struct sg_table *sg;
35 	dma_addr_t dma_addr;
36 	int ret;
37 
38 	sg = kzalloc(sizeof(*sg), GFP_KERNEL);
39 	if (!sg)
40 		return ERR_PTR(-ENOMEM);
41 
42 	/* camera, etc, need physically contiguous.. but we need a
43 	 * better way to know this..
44 	 */
45 	ret = omap_gem_pin(obj, &dma_addr);
46 	if (ret)
47 		goto out;
48 
49 	ret = sg_alloc_table(sg, 1, GFP_KERNEL);
50 	if (ret)
51 		goto out;
52 
53 	sg_init_table(sg->sgl, 1);
54 	sg_dma_len(sg->sgl) = obj->size;
55 	sg_set_page(sg->sgl, pfn_to_page(PFN_DOWN(dma_addr)), obj->size, 0);
56 	sg_dma_address(sg->sgl) = dma_addr;
57 
58 	/* this must be after omap_gem_pin() to ensure we have pages attached */
59 	omap_gem_dma_sync_buffer(obj, dir);
60 
61 	return sg;
62 out:
63 	kfree(sg);
64 	return ERR_PTR(ret);
65 }
66 
67 static void omap_gem_unmap_dma_buf(struct dma_buf_attachment *attachment,
68 		struct sg_table *sg, enum dma_data_direction dir)
69 {
70 	struct drm_gem_object *obj = attachment->dmabuf->priv;
71 	omap_gem_unpin(obj);
72 	sg_free_table(sg);
73 	kfree(sg);
74 }
75 
76 static int omap_gem_dmabuf_begin_cpu_access(struct dma_buf *buffer,
77 		enum dma_data_direction dir)
78 {
79 	struct drm_gem_object *obj = buffer->priv;
80 	struct page **pages;
81 	if (omap_gem_flags(obj) & OMAP_BO_TILED) {
82 		/* TODO we would need to pin at least part of the buffer to
83 		 * get de-tiled view.  For now just reject it.
84 		 */
85 		return -ENOMEM;
86 	}
87 	/* make sure we have the pages: */
88 	return omap_gem_get_pages(obj, &pages, true);
89 }
90 
91 static int omap_gem_dmabuf_end_cpu_access(struct dma_buf *buffer,
92 					  enum dma_data_direction dir)
93 {
94 	struct drm_gem_object *obj = buffer->priv;
95 	omap_gem_put_pages(obj);
96 	return 0;
97 }
98 
99 static void *omap_gem_dmabuf_kmap(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(pages[page_num]);
107 }
108 
109 static void omap_gem_dmabuf_kunmap(struct dma_buf *buffer,
110 		unsigned long page_num, void *addr)
111 {
112 	struct drm_gem_object *obj = buffer->priv;
113 	struct page **pages;
114 	omap_gem_get_pages(obj, &pages, false);
115 	kunmap(pages[page_num]);
116 }
117 
118 static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
119 		struct vm_area_struct *vma)
120 {
121 	struct drm_gem_object *obj = buffer->priv;
122 	int ret = 0;
123 
124 	ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
125 	if (ret < 0)
126 		return ret;
127 
128 	return omap_gem_mmap_obj(obj, vma);
129 }
130 
131 static const struct dma_buf_ops omap_dmabuf_ops = {
132 	.map_dma_buf = omap_gem_map_dma_buf,
133 	.unmap_dma_buf = omap_gem_unmap_dma_buf,
134 	.release = drm_gem_dmabuf_release,
135 	.begin_cpu_access = omap_gem_dmabuf_begin_cpu_access,
136 	.end_cpu_access = omap_gem_dmabuf_end_cpu_access,
137 	.map = omap_gem_dmabuf_kmap,
138 	.unmap = omap_gem_dmabuf_kunmap,
139 	.mmap = omap_gem_dmabuf_mmap,
140 };
141 
142 struct dma_buf *omap_gem_prime_export(struct drm_gem_object *obj, int flags)
143 {
144 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
145 
146 	exp_info.ops = &omap_dmabuf_ops;
147 	exp_info.size = obj->size;
148 	exp_info.flags = flags;
149 	exp_info.priv = obj;
150 
151 	return drm_gem_dmabuf_export(obj->dev, &exp_info);
152 }
153 
154 /* -----------------------------------------------------------------------------
155  * DMABUF Import
156  */
157 
158 struct drm_gem_object *omap_gem_prime_import(struct drm_device *dev,
159 					     struct dma_buf *dma_buf)
160 {
161 	struct dma_buf_attachment *attach;
162 	struct drm_gem_object *obj;
163 	struct sg_table *sgt;
164 	int ret;
165 
166 	if (dma_buf->ops == &omap_dmabuf_ops) {
167 		obj = dma_buf->priv;
168 		if (obj->dev == dev) {
169 			/*
170 			 * Importing dmabuf exported from out own gem increases
171 			 * refcount on gem itself instead of f_count of dmabuf.
172 			 */
173 			drm_gem_object_get(obj);
174 			return obj;
175 		}
176 	}
177 
178 	attach = dma_buf_attach(dma_buf, dev->dev);
179 	if (IS_ERR(attach))
180 		return ERR_CAST(attach);
181 
182 	get_dma_buf(dma_buf);
183 
184 	sgt = dma_buf_map_attachment(attach, DMA_TO_DEVICE);
185 	if (IS_ERR(sgt)) {
186 		ret = PTR_ERR(sgt);
187 		goto fail_detach;
188 	}
189 
190 	obj = omap_gem_new_dmabuf(dev, dma_buf->size, sgt);
191 	if (IS_ERR(obj)) {
192 		ret = PTR_ERR(obj);
193 		goto fail_unmap;
194 	}
195 
196 	obj->import_attach = attach;
197 
198 	return obj;
199 
200 fail_unmap:
201 	dma_buf_unmap_attachment(attach, sgt, DMA_TO_DEVICE);
202 fail_detach:
203 	dma_buf_detach(dma_buf, attach);
204 	dma_buf_put(dma_buf);
205 
206 	return ERR_PTR(ret);
207 }
208