drivers/media/video/videobuf2-vmalloc.c

   1 /*
   2  * videobuf2-vmalloc.c - vmalloc 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/io.h>
  14 #include <linux/module.h>
  15 #include <linux/mm.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/vmalloc.h>
  19
  20 #include <media/videobuf2-core.h>
  21 #include <media/videobuf2-memops.h>
  22
  23 struct vb2_vmalloc_buf {
  24         void                            *vaddr;
  25         struct page                     **pages;
  26         struct vm_area_struct           *vma;
  27         int                             write;
  28         unsigned long                   size;
  29         unsigned int                    n_pages;
  30         atomic_t                        refcount;
  31         struct vb2_vmarea_handler       handler;
  32 };
  33
  34 static void vb2_vmalloc_put(void *buf_priv);
  35
  36 static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size)
  37 {
  38         struct vb2_vmalloc_buf *buf;
  39
  40         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
  41         if (!buf)
  42                 return NULL;
  43
  44         buf->size = size;
  45         buf->vaddr = vmalloc_user(buf->size);
  46         buf->handler.refcount = &buf->refcount;
  47         buf->handler.put = vb2_vmalloc_put;
  48         buf->handler.arg = buf;
  49
  50         if (!buf->vaddr) {
  51                 pr_debug("vmalloc of size %ld failed\n", buf->size);
  52                 kfree(buf);
  53                 return NULL;
  54         }
  55
  56         atomic_inc(&buf->refcount);
  57         return buf;
  58 }
  59
  60 static void vb2_vmalloc_put(void *buf_priv)
  61 {
  62         struct vb2_vmalloc_buf *buf = buf_priv;
  63
  64         if (atomic_dec_and_test(&buf->refcount)) {
  65                 vfree(buf->vaddr);
  66                 kfree(buf);
  67         }
  68 }
  69
  70 static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
  71                                      unsigned long size, int write)
  72 {
  73         struct vb2_vmalloc_buf *buf;
  74         unsigned long first, last;
  75         int n_pages, offset;
  76         struct vm_area_struct *vma;
  77         dma_addr_t physp;
  78
  79         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
  80         if (!buf)
  81                 return NULL;
  82
  83         buf->write = write;
  84         offset = vaddr & ~PAGE_MASK;
  85         buf->size = size;
  86
  87
  88         vma = find_vma(current->mm, vaddr);
  89         if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) {
  90                 if (vb2_get_contig_userptr(vaddr, size, &vma, &physp))
  91                         goto fail_pages_array_alloc;
  92                 buf->vma = vma;
  93                 buf->vaddr = ioremap_nocache(physp, size);
  94                 if (!buf->vaddr)
  95                         goto fail_pages_array_alloc;
  96         } else {
  97                 first = vaddr >> PAGE_SHIFT;
  98                 last  = (vaddr + size - 1) >> PAGE_SHIFT;
  99                 buf->n_pages = last - first + 1;
 100                 buf->pages = kzalloc(buf->n_pages * sizeof(struct page *),
 101                                      GFP_KERNEL);
 102                 if (!buf->pages)
 103                         goto fail_pages_array_alloc;
 104
 105                 /* current->mm->mmap_sem is taken by videobuf2 core */
 106                 n_pages = get_user_pages(current, current->mm,
 107                                          vaddr & PAGE_MASK, buf->n_pages,
 108                                          write, 1, /* force */
 109                                          buf->pages, NULL);
 110                 if (n_pages != buf->n_pages)
 111                         goto fail_get_user_pages;
 112
 113                 buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1,
 114                                         PAGE_KERNEL);
 115                 if (!buf->vaddr)
 116                         goto fail_get_user_pages;
 117         }
 118
 119         buf->vaddr += offset;
 120         return buf;
 121
 122 fail_get_user_pages:
 123         pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
 124                  buf->n_pages);
 125         while (--n_pages >= 0)
 126                 put_page(buf->pages[n_pages]);
 127         kfree(buf->pages);
 128
 129 fail_pages_array_alloc:
 130         kfree(buf);
 131
 132         return NULL;
 133 }
 134
 135 static void vb2_vmalloc_put_userptr(void *buf_priv)
 136 {
 137         struct vb2_vmalloc_buf *buf = buf_priv;
 138         unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
 139         unsigned int i;
 140
 141         if (buf->pages) {
 142                 if (vaddr)
 143                         vm_unmap_ram((void *)vaddr, buf->n_pages);
 144                 for (i = 0; i < buf->n_pages; ++i) {
 145                         if (buf->write)
 146                                 set_page_dirty_lock(buf->pages[i]);
 147                         put_page(buf->pages[i]);
 148                 }
 149                 kfree(buf->pages);
 150         } else {
 151                 if (buf->vma)
 152                         vb2_put_vma(buf->vma);
 153                 iounmap(buf->vaddr);
 154         }
 155         kfree(buf);
 156 }
 157
 158 static void *vb2_vmalloc_vaddr(void *buf_priv)
 159 {
 160         struct vb2_vmalloc_buf *buf = buf_priv;
 161
 162         if (!buf->vaddr) {
 163                 pr_err("Address of an unallocated plane requested "
 164                        "or cannot map user pointer\n");
 165                 return NULL;
 166         }
 167
 168         return buf->vaddr;
 169 }
 170
 171 static unsigned int vb2_vmalloc_num_users(void *buf_priv)
 172 {
 173         struct vb2_vmalloc_buf *buf = buf_priv;
 174         return atomic_read(&buf->refcount);
 175 }
 176
 177 static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
 178 {
 179         struct vb2_vmalloc_buf *buf = buf_priv;
 180         int ret;
 181
 182         if (!buf) {
 183                 pr_err("No memory to map\n");
 184                 return -EINVAL;
 185         }
 186
 187         ret = remap_vmalloc_range(vma, buf->vaddr, 0);
 188         if (ret) {
 189                 pr_err("Remapping vmalloc memory, error: %d\n", ret);
 190                 return ret;
 191         }
 192
 193         /*
 194          * Make sure that vm_areas for 2 buffers won't be merged together
 195          */
 196         vma->vm_flags           |= VM_DONTEXPAND;
 197
 198         /*
 199          * Use common vm_area operations to track buffer refcount.
 200          */
 201         vma->vm_private_data    = &buf->handler;
 202         vma->vm_ops             = &vb2_common_vm_ops;
 203
 204         vma->vm_ops->open(vma);
 205
 206         return 0;
 207 }
 208
 209 const struct vb2_mem_ops vb2_vmalloc_memops = {
 210         .alloc          = vb2_vmalloc_alloc,
 211         .put            = vb2_vmalloc_put,
 212         .get_userptr    = vb2_vmalloc_get_userptr,
 213         .put_userptr    = vb2_vmalloc_put_userptr,
 214         .vaddr          = vb2_vmalloc_vaddr,
 215         .mmap           = vb2_vmalloc_mmap,
 216         .num_users      = vb2_vmalloc_num_users,
 217 };
 218 EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
 219
 220 MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
 221 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
 222 MODULE_LICENSE("GPL");