drivers/media/v4l2-core/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-vmalloc.h>
  22 #include <media/videobuf2-memops.h>
  23
  24 struct vb2_vmalloc_buf {
  25         void                            *vaddr;
  26         struct page                     **pages;
  27         struct vm_area_struct           *vma;
  28         int                             write;
  29         unsigned long                   size;
  30         unsigned int                    n_pages;
  31         atomic_t                        refcount;
  32         struct vb2_vmarea_handler       handler;
  33         struct dma_buf                  *dbuf;
  34 };
  35
  36 static void vb2_vmalloc_put(void *buf_priv);
  37
  38 static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
  39 {
  40         struct vb2_vmalloc_buf *buf;
  41
  42         buf = kzalloc(sizeof(*buf), GFP_KERNEL | gfp_flags);
  43         if (!buf)
  44                 return NULL;
  45
  46         buf->size = size;
  47         buf->vaddr = vmalloc_user(buf->size);
  48         buf->handler.refcount = &buf->refcount;
  49         buf->handler.put = vb2_vmalloc_put;
  50         buf->handler.arg = buf;
  51
  52         if (!buf->vaddr) {
  53                 pr_debug("vmalloc of size %ld failed\n", buf->size);
  54                 kfree(buf);
  55                 return NULL;
  56         }
  57
  58         atomic_inc(&buf->refcount);
  59         return buf;
  60 }
  61
  62 static void vb2_vmalloc_put(void *buf_priv)
  63 {
  64         struct vb2_vmalloc_buf *buf = buf_priv;
  65
  66         if (atomic_dec_and_test(&buf->refcount)) {
  67                 vfree(buf->vaddr);
  68                 kfree(buf);
  69         }
  70 }
  71
  72 static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
  73                                      unsigned long size, int write)
  74 {
  75         struct vb2_vmalloc_buf *buf;
  76         unsigned long first, last;
  77         int n_pages, offset;
  78         struct vm_area_struct *vma;
  79         dma_addr_t physp;
  80
  81         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
  82         if (!buf)
  83                 return NULL;
  84
  85         buf->write = write;
  86         offset = vaddr & ~PAGE_MASK;
  87         buf->size = size;
  88
  89
  90         vma = find_vma(current->mm, vaddr);
  91         if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) {
  92                 if (vb2_get_contig_userptr(vaddr, size, &vma, &physp))
  93                         goto fail_pages_array_alloc;
  94                 buf->vma = vma;
  95                 buf->vaddr = ioremap_nocache(physp, size);
  96                 if (!buf->vaddr)
  97                         goto fail_pages_array_alloc;
  98         } else {
  99                 first = vaddr >> PAGE_SHIFT;
 100                 last  = (vaddr + size - 1) >> PAGE_SHIFT;
 101                 buf->n_pages = last - first + 1;
 102                 buf->pages = kzalloc(buf->n_pages * sizeof(struct page *),
 103                                      GFP_KERNEL);
 104                 if (!buf->pages)
 105                         goto fail_pages_array_alloc;
 106
 107                 /* current->mm->mmap_sem is taken by videobuf2 core */
 108                 n_pages = get_user_pages(current, current->mm,
 109                                          vaddr & PAGE_MASK, buf->n_pages,
 110                                          write, 1, /* force */
 111                                          buf->pages, NULL);
 112                 if (n_pages != buf->n_pages)
 113                         goto fail_get_user_pages;
 114
 115                 buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1,
 116                                         PAGE_KERNEL);
 117                 if (!buf->vaddr)
 118                         goto fail_get_user_pages;
 119         }
 120
 121         buf->vaddr += offset;
 122         return buf;
 123
 124 fail_get_user_pages:
 125         pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
 126                  buf->n_pages);
 127         while (--n_pages >= 0)
 128                 put_page(buf->pages[n_pages]);
 129         kfree(buf->pages);
 130
 131 fail_pages_array_alloc:
 132         kfree(buf);
 133
 134         return NULL;
 135 }
 136
 137 static void vb2_vmalloc_put_userptr(void *buf_priv)
 138 {
 139         struct vb2_vmalloc_buf *buf = buf_priv;
 140         unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
 141         unsigned int i;
 142
 143         if (buf->pages) {
 144                 if (vaddr)
 145                         vm_unmap_ram((void *)vaddr, buf->n_pages);
 146                 for (i = 0; i < buf->n_pages; ++i) {
 147                         if (buf->write)
 148                                 set_page_dirty_lock(buf->pages[i]);
 149                         put_page(buf->pages[i]);
 150                 }
 151                 kfree(buf->pages);
 152         } else {
 153                 if (buf->vma)
 154                         vb2_put_vma(buf->vma);
 155                 iounmap(buf->vaddr);
 156         }
 157         kfree(buf);
 158 }
 159
 160 static void *vb2_vmalloc_vaddr(void *buf_priv)
 161 {
 162         struct vb2_vmalloc_buf *buf = buf_priv;
 163
 164         if (!buf->vaddr) {
 165                 pr_err("Address of an unallocated plane requested "
 166                        "or cannot map user pointer\n");
 167                 return NULL;
 168         }
 169
 170         return buf->vaddr;
 171 }
 172
 173 static unsigned int vb2_vmalloc_num_users(void *buf_priv)
 174 {
 175         struct vb2_vmalloc_buf *buf = buf_priv;
 176         return atomic_read(&buf->refcount);
 177 }
 178
 179 static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
 180 {
 181         struct vb2_vmalloc_buf *buf = buf_priv;
 182         int ret;
 183
 184         if (!buf) {
 185                 pr_err("No memory to map\n");
 186                 return -EINVAL;
 187         }
 188
 189         ret = remap_vmalloc_range(vma, buf->vaddr, 0);
 190         if (ret) {
 191                 pr_err("Remapping vmalloc memory, error: %d\n", ret);
 192                 return ret;
 193         }
 194
 195         /*
 196          * Make sure that vm_areas for 2 buffers won't be merged together
 197          */
 198         vma->vm_flags           |= VM_DONTEXPAND;
 199
 200         /*
 201          * Use common vm_area operations to track buffer refcount.
 202          */
 203         vma->vm_private_data    = &buf->handler;
 204         vma->vm_ops             = &vb2_common_vm_ops;
 205
 206         vma->vm_ops->open(vma);
 207
 208         return 0;
 209 }
 210
 211 /*********************************************/
 212 /*       callbacks for DMABUF buffers        */
 213 /*********************************************/
 214
 215 static int vb2_vmalloc_map_dmabuf(void *mem_priv)
 216 {
 217         struct vb2_vmalloc_buf *buf = mem_priv;
 218
 219         buf->vaddr = dma_buf_vmap(buf->dbuf);
 220
 221         return buf->vaddr ? 0 : -EFAULT;
 222 }
 223
 224 static void vb2_vmalloc_unmap_dmabuf(void *mem_priv)
 225 {
 226         struct vb2_vmalloc_buf *buf = mem_priv;
 227
 228         dma_buf_vunmap(buf->dbuf, buf->vaddr);
 229         buf->vaddr = NULL;
 230 }
 231
 232 static void vb2_vmalloc_detach_dmabuf(void *mem_priv)
 233 {
 234         struct vb2_vmalloc_buf *buf = mem_priv;
 235
 236         if (buf->vaddr)
 237                 dma_buf_vunmap(buf->dbuf, buf->vaddr);
 238
 239         kfree(buf);
 240 }
 241
 242 static void *vb2_vmalloc_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
 243         unsigned long size, int write)
 244 {
 245         struct vb2_vmalloc_buf *buf;
 246
 247         if (dbuf->size < size)
 248                 return ERR_PTR(-EFAULT);
 249
 250         buf = kzalloc(sizeof(*buf), GFP_KERNEL);
 251         if (!buf)
 252                 return ERR_PTR(-ENOMEM);
 253
 254         buf->dbuf = dbuf;
 255         buf->write = write;
 256         buf->size = size;
 257
 258         return buf;
 259 }
 260
 261
 262 const struct vb2_mem_ops vb2_vmalloc_memops = {
 263         .alloc          = vb2_vmalloc_alloc,
 264         .put            = vb2_vmalloc_put,
 265         .get_userptr    = vb2_vmalloc_get_userptr,
 266         .put_userptr    = vb2_vmalloc_put_userptr,
 267         .map_dmabuf     = vb2_vmalloc_map_dmabuf,
 268         .unmap_dmabuf   = vb2_vmalloc_unmap_dmabuf,
 269         .attach_dmabuf  = vb2_vmalloc_attach_dmabuf,
 270         .detach_dmabuf  = vb2_vmalloc_detach_dmabuf,
 271         .vaddr          = vb2_vmalloc_vaddr,
 272         .mmap           = vb2_vmalloc_mmap,
 273         .num_users      = vb2_vmalloc_num_users,
 274 };
 275 EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
 276
 277 MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
 278 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
 279 MODULE_LICENSE("GPL");