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-dma-contig.h>
19 #include <media/videobuf2-memops.h>
20
21 struct vb2_dc_conf {
22 struct device *dev;
23 };
24
25 struct vb2_dc_buf {
26 struct vb2_dc_conf *conf;
27 void *vaddr;
28 dma_addr_t dma_addr;
29 unsigned long size;
30 struct vm_area_struct *vma;
31 atomic_t refcount;
32 struct vb2_vmarea_handler handler;
33 };
34
35 static void vb2_dma_contig_put(void *buf_priv);
36
vb2_dma_contig_alloc(void * alloc_ctx,unsigned long size)37 static void *vb2_dma_contig_alloc(void *alloc_ctx, unsigned long size)
38 {
39 struct vb2_dc_conf *conf = alloc_ctx;
40 struct vb2_dc_buf *buf;
41
42 buf = kzalloc(sizeof *buf, GFP_KERNEL);
43 if (!buf)
44 return ERR_PTR(-ENOMEM);
45
46 buf->vaddr = dma_alloc_coherent(conf->dev, size, &buf->dma_addr,
47 GFP_KERNEL);
48 if (!buf->vaddr) {
49 dev_err(conf->dev, "dma_alloc_coherent of size %ld failed\n",
50 size);
51 kfree(buf);
52 return ERR_PTR(-ENOMEM);
53 }
54
55 buf->conf = conf;
56 buf->size = size;
57
58 buf->handler.refcount = &buf->refcount;
59 buf->handler.put = vb2_dma_contig_put;
60 buf->handler.arg = buf;
61
62 atomic_inc(&buf->refcount);
63
64 return buf;
65 }
66
vb2_dma_contig_put(void * buf_priv)67 static void vb2_dma_contig_put(void *buf_priv)
68 {
69 struct vb2_dc_buf *buf = buf_priv;
70
71 if (atomic_dec_and_test(&buf->refcount)) {
72 dma_free_coherent(buf->conf->dev, buf->size, buf->vaddr,
73 buf->dma_addr);
74 kfree(buf);
75 }
76 }
77
vb2_dma_contig_cookie(void * buf_priv)78 static void *vb2_dma_contig_cookie(void *buf_priv)
79 {
80 struct vb2_dc_buf *buf = buf_priv;
81
82 return &buf->dma_addr;
83 }
84
vb2_dma_contig_vaddr(void * buf_priv)85 static void *vb2_dma_contig_vaddr(void *buf_priv)
86 {
87 struct vb2_dc_buf *buf = buf_priv;
88 if (!buf)
89 return NULL;
90
91 return buf->vaddr;
92 }
93
vb2_dma_contig_num_users(void * buf_priv)94 static unsigned int vb2_dma_contig_num_users(void *buf_priv)
95 {
96 struct vb2_dc_buf *buf = buf_priv;
97
98 return atomic_read(&buf->refcount);
99 }
100
vb2_dma_contig_mmap(void * buf_priv,struct vm_area_struct * vma)101 static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
102 {
103 struct vb2_dc_buf *buf = buf_priv;
104
105 if (!buf) {
106 printk(KERN_ERR "No buffer to map\n");
107 return -EINVAL;
108 }
109
110 return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
111 &vb2_common_vm_ops, &buf->handler);
112 }
113
vb2_dma_contig_get_userptr(void * alloc_ctx,unsigned long vaddr,unsigned long size,int write)114 static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr,
115 unsigned long size, int write)
116 {
117 struct vb2_dc_buf *buf;
118 struct vm_area_struct *vma;
119 dma_addr_t dma_addr = 0;
120 int ret;
121
122 buf = kzalloc(sizeof *buf, GFP_KERNEL);
123 if (!buf)
124 return ERR_PTR(-ENOMEM);
125
126 ret = vb2_get_contig_userptr(vaddr, size, &vma, &dma_addr);
127 if (ret) {
128 printk(KERN_ERR "Failed acquiring VMA for vaddr 0x%08lx\n",
129 vaddr);
130 kfree(buf);
131 return ERR_PTR(ret);
132 }
133
134 buf->size = size;
135 buf->dma_addr = dma_addr;
136 buf->vma = vma;
137
138 return buf;
139 }
140
vb2_dma_contig_put_userptr(void * mem_priv)141 static void vb2_dma_contig_put_userptr(void *mem_priv)
142 {
143 struct vb2_dc_buf *buf = mem_priv;
144
145 if (!buf)
146 return;
147
148 vb2_put_vma(buf->vma);
149 kfree(buf);
150 }
151
152 const struct vb2_mem_ops vb2_dma_contig_memops = {
153 .alloc = vb2_dma_contig_alloc,
154 .put = vb2_dma_contig_put,
155 .cookie = vb2_dma_contig_cookie,
156 .vaddr = vb2_dma_contig_vaddr,
157 .mmap = vb2_dma_contig_mmap,
158 .get_userptr = vb2_dma_contig_get_userptr,
159 .put_userptr = vb2_dma_contig_put_userptr,
160 .num_users = vb2_dma_contig_num_users,
161 };
162 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
163
vb2_dma_contig_init_ctx(struct device * dev)164 void *vb2_dma_contig_init_ctx(struct device *dev)
165 {
166 struct vb2_dc_conf *conf;
167
168 conf = kzalloc(sizeof *conf, GFP_KERNEL);
169 if (!conf)
170 return ERR_PTR(-ENOMEM);
171
172 conf->dev = dev;
173
174 return conf;
175 }
176 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
177
vb2_dma_contig_cleanup_ctx(void * alloc_ctx)178 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
179 {
180 kfree(alloc_ctx);
181 }
182 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
183
184 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
185 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
186 MODULE_LICENSE("GPL");
187