drivers/media/v4l2-core/videobuf2-dma-contig.c

   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 device                   *dev;
  27         void                            *vaddr;
  28         unsigned long                   size;
  29         dma_addr_t                      dma_addr;
  30
  31         /* MMAP related */
  32         struct vb2_vmarea_handler       handler;
  33         atomic_t                        refcount;
  34
  35         /* USERPTR related */
  36         struct vm_area_struct           *vma;
  37 };
  38
  39 /*********************************************/
  40 /*         callbacks for all buffers         */
  41 /*********************************************/
  42
  43 static void *vb2_dc_cookie(void *buf_priv)
  44 {
  45         struct vb2_dc_buf *buf = buf_priv;
  46
  47         return &buf->dma_addr;
  48 }
  49
  50 static void *vb2_dc_vaddr(void *buf_priv)
  51 {
  52         struct vb2_dc_buf *buf = buf_priv;
  53
  54         return buf->vaddr;
  55 }
  56
  57 static unsigned int vb2_dc_num_users(void *buf_priv)
  58 {
  59         struct vb2_dc_buf *buf = buf_priv;
  60
  61         return atomic_read(&buf->refcount);
  62 }
  63
  64 /*********************************************/
  65 /*        callbacks for MMAP buffers         */
  66 /*********************************************/
  67
  68 static void vb2_dc_put(void *buf_priv)
  69 {
  70         struct vb2_dc_buf *buf = buf_priv;
  71
  72         if (!atomic_dec_and_test(&buf->refcount))
  73                 return;
  74
  75         dma_free_coherent(buf->dev, buf->size, buf->vaddr, buf->dma_addr);
  76         kfree(buf);
  77 }
  78
  79 static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
  80 {
  81         struct vb2_dc_conf *conf = alloc_ctx;
  82         struct device *dev = conf->dev;
  83         struct vb2_dc_buf *buf;
  84
  85         buf = kzalloc(sizeof *buf, GFP_KERNEL);
  86         if (!buf)
  87                 return ERR_PTR(-ENOMEM);
  88
  89         buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
  90         if (!buf->vaddr) {
  91                 dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
  92                 kfree(buf);
  93                 return ERR_PTR(-ENOMEM);
  94         }
  95
  96         buf->dev = dev;
  97         buf->size = size;
  98
  99         buf->handler.refcount = &buf->refcount;
 100         buf->handler.put = vb2_dc_put;
 101         buf->handler.arg = buf;
 102
 103         atomic_inc(&buf->refcount);
 104
 105         return buf;
 106 }
 107
 108 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 109 {
 110         struct vb2_dc_buf *buf = buf_priv;
 111
 112         if (!buf) {
 113                 printk(KERN_ERR "No buffer to map\n");
 114                 return -EINVAL;
 115         }
 116
 117         return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
 118                                   &vb2_common_vm_ops, &buf->handler);
 119 }
 120
 121 /*********************************************/
 122 /*       callbacks for USERPTR buffers       */
 123 /*********************************************/
 124
 125 static void *vb2_dc_get_userptr(void *alloc_ctx, unsigned long vaddr,
 126                                         unsigned long size, int write)
 127 {
 128         struct vb2_dc_buf *buf;
 129         struct vm_area_struct *vma;
 130         dma_addr_t dma_addr = 0;
 131         int ret;
 132
 133         buf = kzalloc(sizeof *buf, GFP_KERNEL);
 134         if (!buf)
 135                 return ERR_PTR(-ENOMEM);
 136
 137         ret = vb2_get_contig_userptr(vaddr, size, &vma, &dma_addr);
 138         if (ret) {
 139                 printk(KERN_ERR "Failed acquiring VMA for vaddr 0x%08lx\n",
 140                                 vaddr);
 141                 kfree(buf);
 142                 return ERR_PTR(ret);
 143         }
 144
 145         buf->size = size;
 146         buf->dma_addr = dma_addr;
 147         buf->vma = vma;
 148
 149         return buf;
 150 }
 151
 152 static void vb2_dc_put_userptr(void *mem_priv)
 153 {
 154         struct vb2_dc_buf *buf = mem_priv;
 155
 156         if (!buf)
 157                 return;
 158
 159         vb2_put_vma(buf->vma);
 160         kfree(buf);
 161 }
 162
 163 /*********************************************/
 164 /*       DMA CONTIG exported functions       */
 165 /*********************************************/
 166
 167 const struct vb2_mem_ops vb2_dma_contig_memops = {
 168         .alloc          = vb2_dc_alloc,
 169         .put            = vb2_dc_put,
 170         .cookie         = vb2_dc_cookie,
 171         .vaddr          = vb2_dc_vaddr,
 172         .mmap           = vb2_dc_mmap,
 173         .get_userptr    = vb2_dc_get_userptr,
 174         .put_userptr    = vb2_dc_put_userptr,
 175         .num_users      = vb2_dc_num_users,
 176 };
 177 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
 178
 179 void *vb2_dma_contig_init_ctx(struct device *dev)
 180 {
 181         struct vb2_dc_conf *conf;
 182
 183         conf = kzalloc(sizeof *conf, GFP_KERNEL);
 184         if (!conf)
 185                 return ERR_PTR(-ENOMEM);
 186
 187         conf->dev = dev;
 188
 189         return conf;
 190 }
 191 EXPORT_SYMBOL_GPL(vb2_dma_contig_init_ctx);
 192
 193 void vb2_dma_contig_cleanup_ctx(void *alloc_ctx)
 194 {
 195         kfree(alloc_ctx);
 196 }
 197 EXPORT_SYMBOL_GPL(vb2_dma_contig_cleanup_ctx);
 198
 199 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
 200 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
 201 MODULE_LICENSE("GPL");