drivers/media/video/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 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
  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
  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
  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
  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
  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
 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
 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
 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
 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
 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");