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exynos_drm_dmabuf.c
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1 /* exynos_drm_dmabuf.c
2  *
3  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
4  * Author: Inki Dae <[email protected]>
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice (including the next
14  * paragraph) shall be included in all copies or substantial portions of the
15  * Software.
16  *
17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20  * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23  * OTHER DEALINGS IN THE SOFTWARE.
24  */
25 
26 #include <drm/drmP.h>
27 #include <drm/exynos_drm.h>
28 #include "exynos_drm_drv.h"
29 #include "exynos_drm_gem.h"
30 
31 #include <linux/dma-buf.h>
32 
33 static struct sg_table *exynos_pages_to_sg(struct page **pages, int nr_pages,
34  unsigned int page_size)
35 {
36  struct sg_table *sgt = NULL;
37  struct scatterlist *sgl;
38  int i, ret;
39 
40  sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
41  if (!sgt)
42  goto out;
43 
44  ret = sg_alloc_table(sgt, nr_pages, GFP_KERNEL);
45  if (ret)
46  goto err_free_sgt;
47 
48  if (page_size < PAGE_SIZE)
49  page_size = PAGE_SIZE;
50 
51  for_each_sg(sgt->sgl, sgl, nr_pages, i)
52  sg_set_page(sgl, pages[i], page_size, 0);
53 
54  return sgt;
55 
56 err_free_sgt:
57  kfree(sgt);
58  sgt = NULL;
59 out:
60  return NULL;
61 }
62 
63 static struct sg_table *
64  exynos_gem_map_dma_buf(struct dma_buf_attachment *attach,
65  enum dma_data_direction dir)
66 {
67  struct exynos_drm_gem_obj *gem_obj = attach->dmabuf->priv;
68  struct drm_device *dev = gem_obj->base.dev;
69  struct exynos_drm_gem_buf *buf;
70  struct sg_table *sgt = NULL;
71  unsigned int npages;
72  int nents;
73 
74  DRM_DEBUG_PRIME("%s\n", __FILE__);
75 
76  mutex_lock(&dev->struct_mutex);
77 
78  buf = gem_obj->buffer;
79 
80  /* there should always be pages allocated. */
81  if (!buf->pages) {
82  DRM_ERROR("pages is null.\n");
83  goto err_unlock;
84  }
85 
86  npages = buf->size / buf->page_size;
87 
88  sgt = exynos_pages_to_sg(buf->pages, npages, buf->page_size);
89  if (!sgt) {
90  DRM_DEBUG_PRIME("exynos_pages_to_sg returned NULL!\n");
91  goto err_unlock;
92  }
93  nents = dma_map_sg(attach->dev, sgt->sgl, sgt->nents, dir);
94 
95  DRM_DEBUG_PRIME("npages = %d buffer size = 0x%lx page_size = 0x%lx\n",
96  npages, buf->size, buf->page_size);
97 
98 err_unlock:
99  mutex_unlock(&dev->struct_mutex);
100  return sgt;
101 }
102 
103 static void exynos_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
104  struct sg_table *sgt,
105  enum dma_data_direction dir)
106 {
107  dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
108  sg_free_table(sgt);
109  kfree(sgt);
110  sgt = NULL;
111 }
112 
113 static void exynos_dmabuf_release(struct dma_buf *dmabuf)
114 {
115  struct exynos_drm_gem_obj *exynos_gem_obj = dmabuf->priv;
116 
117  DRM_DEBUG_PRIME("%s\n", __FILE__);
118 
119  /*
120  * exynos_dmabuf_release() call means that file object's
121  * f_count is 0 and it calls drm_gem_object_handle_unreference()
122  * to drop the references that these values had been increased
123  * at drm_prime_handle_to_fd()
124  */
125  if (exynos_gem_obj->base.export_dma_buf == dmabuf) {
126  exynos_gem_obj->base.export_dma_buf = NULL;
127 
128  /*
129  * drop this gem object refcount to release allocated buffer
130  * and resources.
131  */
132  drm_gem_object_unreference_unlocked(&exynos_gem_obj->base);
133  }
134 }
135 
136 static void *exynos_gem_dmabuf_kmap_atomic(struct dma_buf *dma_buf,
137  unsigned long page_num)
138 {
139  /* TODO */
140 
141  return NULL;
142 }
143 
144 static void exynos_gem_dmabuf_kunmap_atomic(struct dma_buf *dma_buf,
145  unsigned long page_num,
146  void *addr)
147 {
148  /* TODO */
149 }
150 
151 static void *exynos_gem_dmabuf_kmap(struct dma_buf *dma_buf,
152  unsigned long page_num)
153 {
154  /* TODO */
155 
156  return NULL;
157 }
158 
159 static void exynos_gem_dmabuf_kunmap(struct dma_buf *dma_buf,
160  unsigned long page_num, void *addr)
161 {
162  /* TODO */
163 }
164 
165 static int exynos_gem_dmabuf_mmap(struct dma_buf *dma_buf,
166  struct vm_area_struct *vma)
167 {
168  return -ENOTTY;
169 }
170 
171 static struct dma_buf_ops exynos_dmabuf_ops = {
172  .map_dma_buf = exynos_gem_map_dma_buf,
173  .unmap_dma_buf = exynos_gem_unmap_dma_buf,
174  .kmap = exynos_gem_dmabuf_kmap,
175  .kmap_atomic = exynos_gem_dmabuf_kmap_atomic,
176  .kunmap = exynos_gem_dmabuf_kunmap,
177  .kunmap_atomic = exynos_gem_dmabuf_kunmap_atomic,
178  .mmap = exynos_gem_dmabuf_mmap,
179  .release = exynos_dmabuf_release,
180 };
181 
183  struct drm_gem_object *obj, int flags)
184 {
185  struct exynos_drm_gem_obj *exynos_gem_obj = to_exynos_gem_obj(obj);
186 
187  return dma_buf_export(exynos_gem_obj, &exynos_dmabuf_ops,
188  exynos_gem_obj->base.size, 0600);
189 }
190 
191 struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
192  struct dma_buf *dma_buf)
193 {
194  struct dma_buf_attachment *attach;
195  struct sg_table *sgt;
196  struct scatterlist *sgl;
197  struct exynos_drm_gem_obj *exynos_gem_obj;
198  struct exynos_drm_gem_buf *buffer;
199  struct page *page;
200  int ret;
201 
202  DRM_DEBUG_PRIME("%s\n", __FILE__);
203 
204  /* is this one of own objects? */
205  if (dma_buf->ops == &exynos_dmabuf_ops) {
206  struct drm_gem_object *obj;
207 
208  exynos_gem_obj = dma_buf->priv;
209  obj = &exynos_gem_obj->base;
210 
211  /* is it from our device? */
212  if (obj->dev == drm_dev) {
213  drm_gem_object_reference(obj);
214  return obj;
215  }
216  }
217 
218  attach = dma_buf_attach(dma_buf, drm_dev->dev);
219  if (IS_ERR(attach))
220  return ERR_PTR(-EINVAL);
221 
222 
224  if (IS_ERR_OR_NULL(sgt)) {
225  ret = PTR_ERR(sgt);
226  goto err_buf_detach;
227  }
228 
229  buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
230  if (!buffer) {
231  DRM_ERROR("failed to allocate exynos_drm_gem_buf.\n");
232  ret = -ENOMEM;
233  goto err_unmap_attach;
234  }
235 
236  buffer->pages = kzalloc(sizeof(*page) * sgt->nents, GFP_KERNEL);
237  if (!buffer->pages) {
238  DRM_ERROR("failed to allocate pages.\n");
239  ret = -ENOMEM;
240  goto err_free_buffer;
241  }
242 
243  exynos_gem_obj = exynos_drm_gem_init(drm_dev, dma_buf->size);
244  if (!exynos_gem_obj) {
245  ret = -ENOMEM;
246  goto err_free_pages;
247  }
248 
249  sgl = sgt->sgl;
250 
251  if (sgt->nents == 1) {
252  buffer->dma_addr = sg_dma_address(sgt->sgl);
253  buffer->size = sg_dma_len(sgt->sgl);
254 
255  /* always physically continuous memory if sgt->nents is 1. */
256  exynos_gem_obj->flags |= EXYNOS_BO_CONTIG;
257  } else {
258  unsigned int i = 0;
259 
260  buffer->dma_addr = sg_dma_address(sgl);
261  while (i < sgt->nents) {
262  buffer->pages[i] = sg_page(sgl);
263  buffer->size += sg_dma_len(sgl);
264  sgl = sg_next(sgl);
265  i++;
266  }
267 
268  exynos_gem_obj->flags |= EXYNOS_BO_NONCONTIG;
269  }
270 
271  exynos_gem_obj->buffer = buffer;
272  buffer->sgt = sgt;
273  exynos_gem_obj->base.import_attach = attach;
274 
275  DRM_DEBUG_PRIME("dma_addr = 0x%x, size = 0x%lx\n", buffer->dma_addr,
276  buffer->size);
277 
278  return &exynos_gem_obj->base;
279 
280 err_free_pages:
281  kfree(buffer->pages);
282  buffer->pages = NULL;
283 err_free_buffer:
284  kfree(buffer);
285  buffer = NULL;
286 err_unmap_attach:
288 err_buf_detach:
289  dma_buf_detach(dma_buf, attach);
290  return ERR_PTR(ret);
291 }
292 
293 MODULE_AUTHOR("Inki Dae <[email protected]>");
294 MODULE_DESCRIPTION("Samsung SoC DRM DMABUF Module");
295 MODULE_LICENSE("GPL");