1 /*
2 * videobuf2-vmalloc.c - vmalloc memory allocator for videobuf2
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 *
6 * Author: Pawel Osciak <pawel@osciak.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation.
11 */
12
13 #include <linux/io.h>
14 #include <linux/module.h>
15 #include <linux/mm.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/vmalloc.h>
19
20 #include <media/videobuf2-core.h>
21 #include <media/videobuf2-vmalloc.h>
22 #include <media/videobuf2-memops.h>
23
24 struct vb2_vmalloc_buf {
25 void *vaddr;
26 struct page **pages;
27 struct vm_area_struct *vma;
28 int write;
29 unsigned long size;
30 unsigned int n_pages;
31 atomic_t refcount;
32 struct vb2_vmarea_handler handler;
33 struct dma_buf *dbuf;
34 };
35
36 static void vb2_vmalloc_put(void *buf_priv);
37
vb2_vmalloc_alloc(void * alloc_ctx,unsigned long size,gfp_t gfp_flags)38 static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
39 {
40 struct vb2_vmalloc_buf *buf;
41
42 buf = kzalloc(sizeof(*buf), GFP_KERNEL | gfp_flags);
43 if (!buf)
44 return NULL;
45
46 buf->size = size;
47 buf->vaddr = vmalloc_user(buf->size);
48 buf->handler.refcount = &buf->refcount;
49 buf->handler.put = vb2_vmalloc_put;
50 buf->handler.arg = buf;
51
52 if (!buf->vaddr) {
53 pr_debug("vmalloc of size %ld failed\n", buf->size);
54 kfree(buf);
55 return NULL;
56 }
57
58 atomic_inc(&buf->refcount);
59 return buf;
60 }
61
vb2_vmalloc_put(void * buf_priv)62 static void vb2_vmalloc_put(void *buf_priv)
63 {
64 struct vb2_vmalloc_buf *buf = buf_priv;
65
66 if (atomic_dec_and_test(&buf->refcount)) {
67 vfree(buf->vaddr);
68 kfree(buf);
69 }
70 }
71
vb2_vmalloc_get_userptr(void * alloc_ctx,unsigned long vaddr,unsigned long size,int write)72 static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
73 unsigned long size, int write)
74 {
75 struct vb2_vmalloc_buf *buf;
76 unsigned long first, last;
77 int n_pages, offset;
78 struct vm_area_struct *vma;
79 dma_addr_t physp;
80
81 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
82 if (!buf)
83 return NULL;
84
85 buf->write = write;
86 offset = vaddr & ~PAGE_MASK;
87 buf->size = size;
88
89
90 vma = find_vma(current->mm, vaddr);
91 if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) {
92 if (vb2_get_contig_userptr(vaddr, size, &vma, &physp))
93 goto fail_pages_array_alloc;
94 buf->vma = vma;
95 buf->vaddr = ioremap_nocache(physp, size);
96 if (!buf->vaddr)
97 goto fail_pages_array_alloc;
98 } else {
99 first = vaddr >> PAGE_SHIFT;
100 last = (vaddr + size - 1) >> PAGE_SHIFT;
101 buf->n_pages = last - first + 1;
102 buf->pages = kzalloc(buf->n_pages * sizeof(struct page *),
103 GFP_KERNEL);
104 if (!buf->pages)
105 goto fail_pages_array_alloc;
106
107 /* current->mm->mmap_sem is taken by videobuf2 core */
108 n_pages = get_user_pages(current, current->mm,
109 vaddr & PAGE_MASK, buf->n_pages,
110 write, 1, /* force */
111 buf->pages, NULL);
112 if (n_pages != buf->n_pages)
113 goto fail_get_user_pages;
114
115 buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1,
116 PAGE_KERNEL);
117 if (!buf->vaddr)
118 goto fail_get_user_pages;
119 }
120
121 buf->vaddr += offset;
122 return buf;
123
124 fail_get_user_pages:
125 pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
126 buf->n_pages);
127 while (--n_pages >= 0)
128 put_page(buf->pages[n_pages]);
129 kfree(buf->pages);
130
131 fail_pages_array_alloc:
132 kfree(buf);
133
134 return NULL;
135 }
136
vb2_vmalloc_put_userptr(void * buf_priv)137 static void vb2_vmalloc_put_userptr(void *buf_priv)
138 {
139 struct vb2_vmalloc_buf *buf = buf_priv;
140 unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
141 unsigned int i;
142
143 if (buf->pages) {
144 if (vaddr)
145 vm_unmap_ram((void *)vaddr, buf->n_pages);
146 for (i = 0; i < buf->n_pages; ++i) {
147 if (buf->write)
148 set_page_dirty_lock(buf->pages[i]);
149 put_page(buf->pages[i]);
150 }
151 kfree(buf->pages);
152 } else {
153 if (buf->vma)
154 vb2_put_vma(buf->vma);
155 iounmap(buf->vaddr);
156 }
157 kfree(buf);
158 }
159
vb2_vmalloc_vaddr(void * buf_priv)160 static void *vb2_vmalloc_vaddr(void *buf_priv)
161 {
162 struct vb2_vmalloc_buf *buf = buf_priv;
163
164 if (!buf->vaddr) {
165 pr_err("Address of an unallocated plane requested "
166 "or cannot map user pointer\n");
167 return NULL;
168 }
169
170 return buf->vaddr;
171 }
172
vb2_vmalloc_num_users(void * buf_priv)173 static unsigned int vb2_vmalloc_num_users(void *buf_priv)
174 {
175 struct vb2_vmalloc_buf *buf = buf_priv;
176 return atomic_read(&buf->refcount);
177 }
178
vb2_vmalloc_mmap(void * buf_priv,struct vm_area_struct * vma)179 static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
180 {
181 struct vb2_vmalloc_buf *buf = buf_priv;
182 int ret;
183
184 if (!buf) {
185 pr_err("No memory to map\n");
186 return -EINVAL;
187 }
188
189 ret = remap_vmalloc_range(vma, buf->vaddr, 0);
190 if (ret) {
191 pr_err("Remapping vmalloc memory, error: %d\n", ret);
192 return ret;
193 }
194
195 /*
196 * Make sure that vm_areas for 2 buffers won't be merged together
197 */
198 vma->vm_flags |= VM_DONTEXPAND;
199
200 /*
201 * Use common vm_area operations to track buffer refcount.
202 */
203 vma->vm_private_data = &buf->handler;
204 vma->vm_ops = &vb2_common_vm_ops;
205
206 vma->vm_ops->open(vma);
207
208 return 0;
209 }
210
211 /*********************************************/
212 /* callbacks for DMABUF buffers */
213 /*********************************************/
214
vb2_vmalloc_map_dmabuf(void * mem_priv)215 static int vb2_vmalloc_map_dmabuf(void *mem_priv)
216 {
217 struct vb2_vmalloc_buf *buf = mem_priv;
218
219 buf->vaddr = dma_buf_vmap(buf->dbuf);
220
221 return buf->vaddr ? 0 : -EFAULT;
222 }
223
vb2_vmalloc_unmap_dmabuf(void * mem_priv)224 static void vb2_vmalloc_unmap_dmabuf(void *mem_priv)
225 {
226 struct vb2_vmalloc_buf *buf = mem_priv;
227
228 dma_buf_vunmap(buf->dbuf, buf->vaddr);
229 buf->vaddr = NULL;
230 }
231
vb2_vmalloc_detach_dmabuf(void * mem_priv)232 static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
233 {
234 struct vb2_vmalloc_buf *buf = mem_priv;
235
236 if (buf->vaddr)
237 dma_buf_vunmap(buf->dbuf, buf->vaddr);
238
239 kfree(buf);
240 }
241
vb2_vmalloc_attach_dmabuf(void * alloc_ctx,struct dma_buf * dbuf,unsigned long size,int write)242 static void *vb2_vmalloc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
243 unsigned long size, int write)
244 {
245 struct vb2_vmalloc_buf *buf;
246
247 if (dbuf->size < size)
248 return ERR_PTR(-EFAULT);
249
250 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
251 if (!buf)
252 return ERR_PTR(-ENOMEM);
253
254 buf->dbuf = dbuf;
255 buf->write = write;
256 buf->size = size;
257
258 return buf;
259 }
260
261
262 const struct vb2_mem_ops vb2_vmalloc_memops = {
263 .alloc = vb2_vmalloc_alloc,
264 .put = vb2_vmalloc_put,
265 .get_userptr = vb2_vmalloc_get_userptr,
266 .put_userptr = vb2_vmalloc_put_userptr,
267 .map_dmabuf = vb2_vmalloc_map_dmabuf,
268 .unmap_dmabuf = vb2_vmalloc_unmap_dmabuf,
269 .attach_dmabuf = vb2_vmalloc_attach_dmabuf,
270 .detach_dmabuf = vb2_vmalloc_detach_dmabuf,
271 .vaddr = vb2_vmalloc_vaddr,
272 .mmap = vb2_vmalloc_mmap,
273 .num_users = vb2_vmalloc_num_users,
274 };
275 EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
276
277 MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
278 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
279 MODULE_LICENSE("GPL");
280