1 /*
2 * videobuf2-dma-contig.c - DMA contig 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/module.h>
14 #include <linux/slab.h>
15 #include <linux/dma-mapping.h>
16
17 #include <media/videobuf2-core.h>
18 #include <media/videobuf2-memops.h>
19
20 struct vb2_dc_conf {
21 struct device *dev;
22 };
23
24 struct vb2_dc_buf {
25 struct vb2_dc_conf *conf;
26 void *vaddr;
27 dma_addr_t dma_addr;
28 unsigned long size;
29 struct vm_area_struct *vma;
30 atomic_t refcount;
31 struct vb2_vmarea_handler handler;
32 };
33
34 static void vb2_dma_contig_put(void *buf_priv);
35
vb2_dma_contig_alloc(void * alloc_ctx,unsigned long size)36 static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size)
37 {
38 struct vb2_dc_conf *conf = alloc_ctx;
39 struct vb2_dc_buf *buf;
40
41 buf = kzalloc(sizeof *buf, GFP_KERNEL);
42 if (!buf)
43 return ERR_PTR(-ENOMEM);
44
45 buf->vaddr = dma_alloc_coherent(conf->dev, size, &buf->dma_addr,
46 GFP_KERNEL);
47 if (!buf->vaddr) {
48 dev_err(conf->dev, "dma_alloc_coherent of size %ld failed\n",
49 size);
50 kfree(buf);
51 return ERR_PTR(-ENOMEM);
52 }
53
54 buf->conf = conf;
55 buf->size = size;
56
57 buf->handler.refcount = &buf->refcount;
58 buf->handler.put = vb2_dma_contig_put;
59 buf->handler.arg = buf;
60
61 atomic_inc(&buf->refcount);
62
63 return buf;
64 }
65
vb2_dma_contig_put(void * buf_priv)66 static void vb2_dma_contig_put(void *buf_priv)
67 {
68 struct vb2_dc_buf *buf = buf_priv;
69
70 if (atomic_dec_and_test(&buf->refcount)) {
71 dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr,
72 buf->dma_addr);
73 kfree(buf);
74 }
75 }
76
vb2_dma_contig_cookie(void * buf_priv)77 static void *vb2_dma_contig_cookie(void *buf_priv)
78 {
79 struct vb2_dc_buf *buf = buf_priv;
80
81 return &buf->dma_addr;
82 }
83
vb2_dma_contig_vaddr(void * buf_priv)84 static void *vb2_dma_contig_vaddr(void *buf_priv)
85 {
86 struct vb2_dc_buf *buf = buf_priv;
87 if (!buf)
88 return 0;
89
90 return buf->vaddr;
91 }
92
vb2_dma_contig_num_users(void * buf_priv)93 static unsigned int vb2_dma_contig_num_users(void *buf_priv)
94 {
95 struct vb2_dc_buf *buf = buf_priv;
96
97 return atomic_read(&buf->refcount);
98 }
99
vb2_dma_contig_mmap(void * buf_priv,struct vm_area_struct * vma)100 static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
101 {
102 struct vb2_dc_buf *buf = buf_priv;
103
104 if (!buf) {
105 printk(KERN_ERR "No buffer to map\n");
106 return -EINVAL;
107 }
108
109 return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
110 &vb2_common_vm_ops, &buf->handler);
111 }
112
vb2_dma_contig_get_userptr(void * alloc_ctx,unsigned long vaddr,unsigned long size,int write)113 static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr,
114 unsigned long size, int write)
115 {
116 struct vb2_dc_buf *buf;
117 struct vm_area_struct *vma;
118 dma_addr_t dma_addr = 0;
119 int ret;
120
121 buf = kzalloc(sizeof *buf, GFP_KERNEL);
122 if (!buf)
123 return ERR_PTR(-ENOMEM);
124
125 ret = vb2_get_contig_userptr(vaddr, size, &vma, &dma_addr);
126 if (ret) {
127 printk(KERN_ERR "Failed acquiring VMA for vaddr 0x%08lx\n",
128 vaddr);
129 kfree(buf);
130 return ERR_PTR(ret);
131 }
132
133 buf->size = size;
134 buf->dma_addr = dma_addr;
135 buf->vma = vma;
136
137 return buf;
138 }
139
vb2_dma_contig_put_userptr(void * mem_priv)140 static void vb2_dma_contig_put_userptr(void *mem_priv)
141 {
142 struct vb2_dc_buf *buf = mem_priv;
143
144 if (!buf)
145 return;
146
147 vb2_put_vma(buf->vma);
148 kfree(buf);
149 }
150
151 const struct vb2_mem_ops vb2_dma_contig_memops = {
152 .alloc = vb2_dma_contig_alloc,
153 .put = vb2_dma_contig_put,
154 .cookie = vb2_dma_contig_cookie,
155 .vaddr = vb2_dma_contig_vaddr,
156 .mmap = vb2_dma_contig_mmap,
157 .get_userptr = vb2_dma_contig_get_userptr,
158 .put_userptr = vb2_dma_contig_put_userptr,
159 .num_users = vb2_dma_contig_num_users,
160 };
161 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
162
vb2_dma_contig_init_ctx(struct device * dev)163 void *vb2_dma_contig_init_ctx(struct device *dev)
164 {
165 struct vb2_dc_conf *conf;
166
167 conf = kzalloc(sizeof *conf, GFP_KERNEL);
168 if (!conf)
169 return ERR_PTR(-ENOMEM);
170
171 conf->dev = dev;
172
173 return conf;
174 }
175 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
176
vb2_dma_contig_cleanup_ctx(void * alloc_ctx)177 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
178 {
179 kfree(alloc_ctx);
180 }
181 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
182
183 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
184 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
185 MODULE_LICENSE("GPL");
186