drivers/media/video/videobuf-vmalloc.c

   1 /*
   2  * helper functions for vmalloc video4linux capture buffers
   3  *
   4  * The functions expect the hardware being able to scatter gather
   5  * (i.e. the buffers are not linear in physical memory, but fragmented
   6  * into PAGE_SIZE chunks).  They also assume the driver does not need
   7  * to touch the video data.
   8  *
   9  * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/slab.h>
  20 #include <linux/interrupt.h>
  21
  22 #include <linux/pci.h>
  23 #include <linux/vmalloc.h>
  24 #include <linux/pagemap.h>
  25 #include <asm/page.h>
  26 #include <asm/pgtable.h>
  27
  28 #include <media/videobuf-vmalloc.h>
  29
  30 #define MAGIC_DMABUF   0x17760309
  31 #define MAGIC_VMAL_MEM 0x18221223
  32
  33 #define MAGIC_CHECK(is, should)                                         \
  34         if (unlikely((is) != (should))) {                               \
  35                 printk(KERN_ERR "magic mismatch: %x (expected %x)\n",   \
  36                                 is, should);                            \
  37                 BUG();                                                  \
  38         }
  39
  40 static int debug;
  41 module_param(debug, int, 0644);
  42
  43 MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
  44 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
  45 MODULE_LICENSE("GPL");
  46
  47 #define dprintk(level, fmt, arg...)                                     \
  48         if (debug >= level)                                             \
  49                 printk(KERN_DEBUG "vbuf-vmalloc: " fmt , ## arg)
  50
  51
  52 /***************************************************************************/
  53
  54 static void videobuf_vm_open(struct vm_area_struct *vma)
  55 {
  56         struct videobuf_mapping *map = vma->vm_private_data;
  57
  58         dprintk(2, "vm_open %p [count=%u,vma=%08lx-%08lx]\n", map,
  59                 map->count, vma->vm_start, vma->vm_end);
  60
  61         map->count++;
  62 }
  63
  64 static void videobuf_vm_close(struct vm_area_struct *vma)
  65 {
  66         struct videobuf_mapping *map = vma->vm_private_data;
  67         struct videobuf_queue *q = map->q;
  68         int i;
  69
  70         dprintk(2, "vm_close %p [count=%u,vma=%08lx-%08lx]\n", map,
  71                 map->count, vma->vm_start, vma->vm_end);
  72
  73         map->count--;
  74         if (0 == map->count) {
  75                 struct videobuf_vmalloc_memory *mem;
  76
  77                 dprintk(1, "munmap %p q=%p\n", map, q);
  78                 videobuf_queue_lock(q);
  79
  80                 /* We need first to cancel streams, before unmapping */
  81                 if (q->streaming)
  82                         videobuf_queue_cancel(q);
  83
  84                 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
  85                         if (NULL == q->bufs[i])
  86                                 continue;
  87
  88                         if (q->bufs[i]->map != map)
  89                                 continue;
  90
  91                         mem = q->bufs[i]->priv;
  92                         if (mem) {
  93                                 /* This callback is called only if kernel has
  94                                    allocated memory and this memory is mmapped.
  95                                    In this case, memory should be freed,
  96                                    in order to do memory unmap.
  97                                  */
  98
  99                                 MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
 100
 101                                 /* vfree is not atomic - can't be
 102                                    called with IRQ's disabled
 103                                  */
 104                                 dprintk(1, "%s: buf[%d] freeing (%p)\n",
 105                                         __func__, i, mem->vaddr);
 106
 107                                 vfree(mem->vaddr);
 108                                 mem->vaddr = NULL;
 109                         }
 110
 111                         q->bufs[i]->map   = NULL;
 112                         q->bufs[i]->baddr = 0;
 113                 }
 114
 115                 kfree(map);
 116
 117                 videobuf_queue_unlock(q);
 118         }
 119
 120         return;
 121 }
 122
 123 static const struct vm_operations_struct videobuf_vm_ops = {
 124         .open     = videobuf_vm_open,
 125         .close    = videobuf_vm_close,
 126 };
 127
 128 /* ---------------------------------------------------------------------
 129  * vmalloc handlers for the generic methods
 130  */
 131
 132 /* Allocated area consists on 3 parts:
 133         struct video_buffer
 134         struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 135         struct videobuf_dma_sg_memory
 136  */
 137
 138 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
 139 {
 140         struct videobuf_vmalloc_memory *mem;
 141         struct videobuf_buffer *vb;
 142
 143         vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
 144         if (!vb)
 145                 return vb;
 146
 147         mem = vb->priv = ((char *)vb) + size;
 148         mem->magic = MAGIC_VMAL_MEM;
 149
 150         dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
 151                 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
 152                 mem, (long)sizeof(*mem));
 153
 154         return vb;
 155 }
 156
 157 static int __videobuf_iolock(struct videobuf_queue *q,
 158                              struct videobuf_buffer *vb,
 159                              struct v4l2_framebuffer *fbuf)
 160 {
 161         struct videobuf_vmalloc_memory *mem = vb->priv;
 162         int pages;
 163
 164         BUG_ON(!mem);
 165
 166         MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
 167
 168         switch (vb->memory) {
 169         case V4L2_MEMORY_MMAP:
 170                 dprintk(1, "%s memory method MMAP\n", __func__);
 171
 172                 /* All handling should be done by __videobuf_mmap_mapper() */
 173                 if (!mem->vaddr) {
 174                         printk(KERN_ERR "memory is not alloced/mmapped.\n");
 175                         return -EINVAL;
 176                 }
 177                 break;
 178         case V4L2_MEMORY_USERPTR:
 179                 pages = PAGE_ALIGN(vb->size);
 180
 181                 dprintk(1, "%s memory method USERPTR\n", __func__);
 182
 183                 if (vb->baddr) {
 184                         printk(KERN_ERR "USERPTR is currently not supported\n");
 185                         return -EINVAL;
 186                 }
 187
 188                 /* The only USERPTR currently supported is the one needed for
 189                  * read() method.
 190                  */
 191
 192                 mem->vaddr = vmalloc_user(pages);
 193                 if (!mem->vaddr) {
 194                         printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
 195                         return -ENOMEM;
 196                 }
 197                 dprintk(1, "vmalloc is at addr %p (%d pages)\n",
 198                         mem->vaddr, pages);
 199
 200 #if 0
 201                 int rc;
 202                 /* Kernel userptr is used also by read() method. In this case,
 203                    there's no need to remap, since data will be copied to user
 204                  */
 205                 if (!vb->baddr)
 206                         return 0;
 207
 208                 /* FIXME: to properly support USERPTR, remap should occur.
 209                    The code below won't work, since mem->vma = NULL
 210                  */
 211                 /* Try to remap memory */
 212                 rc = remap_vmalloc_range(mem->vma, (void *)vb->baddr, 0);
 213                 if (rc < 0) {
 214                         printk(KERN_ERR "mmap: remap failed with error %d", rc);
 215                         return -ENOMEM;
 216                 }
 217 #endif
 218
 219                 break;
 220         case V4L2_MEMORY_OVERLAY:
 221         default:
 222                 dprintk(1, "%s memory method OVERLAY/unknown\n", __func__);
 223
 224                 /* Currently, doesn't support V4L2_MEMORY_OVERLAY */
 225                 printk(KERN_ERR "Memory method currently unsupported.\n");
 226                 return -EINVAL;
 227         }
 228
 229         return 0;
 230 }
 231
 232 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 233                                   struct videobuf_buffer *buf,
 234                                   struct vm_area_struct *vma)
 235 {
 236         struct videobuf_vmalloc_memory *mem;
 237         struct videobuf_mapping *map;
 238         int retval, pages;
 239
 240         dprintk(1, "%s\n", __func__);
 241
 242         /* create mapping + update buffer list */
 243         map = kzalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
 244         if (NULL == map)
 245                 return -ENOMEM;
 246
 247         buf->map = map;
 248         map->q     = q;
 249
 250         buf->baddr = vma->vm_start;
 251
 252         mem = buf->priv;
 253         BUG_ON(!mem);
 254         MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
 255
 256         pages = PAGE_ALIGN(vma->vm_end - vma->vm_start);
 257         mem->vaddr = vmalloc_user(pages);
 258         if (!mem->vaddr) {
 259                 printk(KERN_ERR "vmalloc (%d pages) failed\n", pages);
 260                 goto error;
 261         }
 262         dprintk(1, "vmalloc is at addr %p (%d pages)\n", mem->vaddr, pages);
 263
 264         /* Try to remap memory */
 265         retval = remap_vmalloc_range(vma, mem->vaddr, 0);
 266         if (retval < 0) {
 267                 printk(KERN_ERR "mmap: remap failed with error %d. ", retval);
 268                 vfree(mem->vaddr);
 269                 goto error;
 270         }
 271
 272         vma->vm_ops          = &videobuf_vm_ops;
 273         vma->vm_flags       |= VM_DONTEXPAND | VM_RESERVED;
 274         vma->vm_private_data = map;
 275
 276         dprintk(1, "mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
 277                 map, q, vma->vm_start, vma->vm_end,
 278                 (long int)buf->bsize,
 279                 vma->vm_pgoff, buf->i);
 280
 281         videobuf_vm_open(vma);
 282
 283         return 0;
 284
 285 error:
 286         mem = NULL;
 287         kfree(map);
 288         return -ENOMEM;
 289 }
 290
 291 static struct videobuf_qtype_ops qops = {
 292         .magic        = MAGIC_QTYPE_OPS,
 293
 294         .alloc_vb     = __videobuf_alloc_vb,
 295         .iolock       = __videobuf_iolock,
 296         .mmap_mapper  = __videobuf_mmap_mapper,
 297         .vaddr        = videobuf_to_vmalloc,
 298 };
 299
 300 void videobuf_queue_vmalloc_init(struct videobuf_queue *q,
 301                          const struct videobuf_queue_ops *ops,
 302                          struct device *dev,
 303                          spinlock_t *irqlock,
 304                          enum v4l2_buf_type type,
 305                          enum v4l2_field field,
 306                          unsigned int msize,
 307                          void *priv,
 308                          struct mutex *ext_lock)
 309 {
 310         videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
 311                                  priv, &qops, ext_lock);
 312 }
 313 EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);
 314
 315 void *videobuf_to_vmalloc(struct videobuf_buffer *buf)
 316 {
 317         struct videobuf_vmalloc_memory *mem = buf->priv;
 318         BUG_ON(!mem);
 319         MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
 320
 321         return mem->vaddr;
 322 }
 323 EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);
 324
 325 void videobuf_vmalloc_free(struct videobuf_buffer *buf)
 326 {
 327         struct videobuf_vmalloc_memory *mem = buf->priv;
 328
 329         /* mmapped memory can't be freed here, otherwise mmapped region
 330            would be released, while still needed. In this case, the memory
 331            release should happen inside videobuf_vm_close().
 332            So, it should free memory only if the memory were allocated for
 333            read() operation.
 334          */
 335         if ((buf->memory != V4L2_MEMORY_USERPTR) || buf->baddr)
 336                 return;
 337
 338         if (!mem)
 339                 return;
 340
 341         MAGIC_CHECK(mem->magic, MAGIC_VMAL_MEM);
 342
 343         vfree(mem->vaddr);
 344         mem->vaddr = NULL;
 345
 346         return;
 347 }
 348 EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);
 349