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-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
  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
  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
  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
  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
  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
 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
 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
 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
 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
 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");