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
24static 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;
57out:
58	kfree(sg);
59	return ERR_PTR(ret);
60}
61
62static 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
71static 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
81static 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
96static 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
104static 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
114static void omap_gem_dmabuf_kunmap_atomic(struct dma_buf *buffer,
115		unsigned long page_num, void *addr)
116{
117	kunmap_atomic(addr);
118}
119
120static 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
130static 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
139static 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
158static 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
171struct 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
184struct 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