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   1 /*
   2  * helper functions for vmalloc video4linux capture buffers
   3  *
   4  * The functions expect the hardware being able to scatter gatter
   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)  if (unlikely((is) != (should))) \
  34         { printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); }
  35
  36 static int debug;
  37 module_param(debug, int, 0644);
  38
  39 MODULE_DESCRIPTION("helper module to manage video4linux vmalloc buffers");
  40 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
  41 MODULE_LICENSE("GPL");
  42
  43 #define dprintk(level, fmt, arg...)     if (debug >= level) \
  44         printk(KERN_DEBUG "vbuf-vmalloc: " fmt , ## arg)
  45
  46
  47 /***************************************************************************/
  48
  49 static void
  50 videobuf_vm_open(struct vm_area_struct *vma)
  51 {
  52         struct videobuf_mapping *map = vma->vm_private_data;
  53
  54         dprintk(2,"vm_open %p [count=%u,vma=%08lx-%08lx]\n",map,
  55                 map->count,vma->vm_start,vma->vm_end);
  56
  57         map->count++;
  58 }
  59
  60 static void
  61 videobuf_vm_close(struct vm_area_struct *vma)
  62 {
  63         struct videobuf_mapping *map = vma->vm_private_data;
  64         struct videobuf_queue *q = map->q;
  65         int i;
  66
  67         dprintk(2,"vm_close %p [count=%u,vma=%08lx-%08lx]\n",map,
  68                 map->count,vma->vm_start,vma->vm_end);
  69
  70         map->count--;
  71         if (0 == map->count) {
  72                 dprintk(1,"munmap %p q=%p\n",map,q);
  73                 mutex_lock(&q->vb_lock);
  74                 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
  75                         if (NULL == q->bufs[i])
  76                                 continue;
  77
  78                         if (q->bufs[i]->map != map)
  79                                 continue;
  80
  81                         q->bufs[i]->map   = NULL;
  82                         q->bufs[i]->baddr = 0;
  83                 }
  84                 mutex_unlock(&q->vb_lock);
  85                 kfree(map);
  86         }
  87         return;
  88 }
  89
  90 static struct vm_operations_struct videobuf_vm_ops =
  91 {
  92         .open     = videobuf_vm_open,
  93         .close    = videobuf_vm_close,
  94 };
  95
  96 /* ---------------------------------------------------------------------
  97  * vmalloc handlers for the generic methods
  98  */
  99
 100 /* Allocated area consists on 3 parts:
 101         struct video_buffer
 102         struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
 103         struct videobuf_dma_sg_memory
 104  */
 105
 106 static void *__videobuf_alloc(size_t size)
 107 {
 108         struct videobuf_vmalloc_memory *mem;
 109         struct videobuf_buffer *vb;
 110
 111         vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
 112
 113         mem = vb->priv = ((char *)vb)+size;
 114         mem->magic=MAGIC_VMAL_MEM;
 115
 116         dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
 117                 __FUNCTION__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb),
 118                 mem,(long)sizeof(*mem));
 119
 120         return vb;
 121 }
 122
 123 static int __videobuf_iolock (struct videobuf_queue* q,
 124                               struct videobuf_buffer *vb,
 125                               struct v4l2_framebuffer *fbuf)
 126 {
 127         int pages;
 128         struct videobuf_vmalloc_memory *mem=vb->priv;
 129
 130         BUG_ON(!mem);
 131
 132         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 133
 134         pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
 135
 136         /* Currently, doesn't support V4L2_MEMORY_OVERLAY */
 137         if ((vb->memory != V4L2_MEMORY_MMAP) &&
 138                                 (vb->memory != V4L2_MEMORY_USERPTR) ) {
 139                 printk(KERN_ERR "Method currently unsupported.\n");
 140                 return -EINVAL;
 141         }
 142
 143         /* FIXME: should be tested with kernel mmap mem */
 144         mem->vmalloc=vmalloc_user (PAGE_ALIGN(vb->size));
 145         if (NULL == mem->vmalloc) {
 146                 printk(KERN_ERR "vmalloc (%d pages) failed\n",pages);
 147                 return -ENOMEM;
 148         }
 149
 150         dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
 151                                 (unsigned long)mem->vmalloc,
 152                                 pages << PAGE_SHIFT);
 153
 154         /* It seems that some kernel versions need to do remap *after*
 155            the mmap() call
 156          */
 157         if (mem->vma) {
 158                 int retval=remap_vmalloc_range(mem->vma, mem->vmalloc,0);
 159                 kfree(mem->vma);
 160                 mem->vma=NULL;
 161                 if (retval<0) {
 162                         dprintk(1,"mmap app bug: remap_vmalloc_range area %p error %d\n",
 163                                 mem->vmalloc,retval);
 164                         return retval;
 165                 }
 166         }
 167
 168         return 0;
 169 }
 170
 171 static int __videobuf_sync(struct videobuf_queue *q,
 172                            struct videobuf_buffer *buf)
 173 {
 174         return 0;
 175 }
 176
 177 static int __videobuf_mmap_free(struct videobuf_queue *q)
 178 {
 179         unsigned int i;
 180
 181         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
 182                 if (q->bufs[i]) {
 183                         if (q->bufs[i]->map)
 184                                 return -EBUSY;
 185                 }
 186         }
 187
 188         return 0;
 189 }
 190
 191 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
 192                          struct vm_area_struct *vma)
 193 {
 194         struct videobuf_vmalloc_memory *mem;
 195         struct videobuf_mapping *map;
 196         unsigned int first;
 197         int retval;
 198         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 199
 200         if (! (vma->vm_flags & VM_WRITE) || ! (vma->vm_flags & VM_SHARED))
 201                 return -EINVAL;
 202
 203         /* look for first buffer to map */
 204         for (first = 0; first < VIDEO_MAX_FRAME; first++) {
 205                 if (NULL == q->bufs[first])
 206                         continue;
 207
 208                 if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
 209                         continue;
 210                 if (q->bufs[first]->boff == offset)
 211                         break;
 212         }
 213         if (VIDEO_MAX_FRAME == first) {
 214                 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
 215                         (vma->vm_pgoff << PAGE_SHIFT));
 216                 return -EINVAL;
 217         }
 218
 219         /* create mapping + update buffer list */
 220         map = q->bufs[first]->map = kzalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
 221         if (NULL == map)
 222                 return -ENOMEM;
 223
 224         map->start = vma->vm_start;
 225         map->end   = vma->vm_end;
 226         map->q     = q;
 227
 228         q->bufs[first]->baddr = vma->vm_start;
 229
 230         vma->vm_ops          = &videobuf_vm_ops;
 231         vma->vm_flags       |= VM_DONTEXPAND | VM_RESERVED;
 232         vma->vm_private_data = map;
 233
 234         mem=q->bufs[first]->priv;
 235         BUG_ON (!mem);
 236         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 237
 238         /* Try to remap memory */
 239         retval=remap_vmalloc_range(vma, mem->vmalloc,0);
 240         if (retval<0) {
 241                 dprintk(1,"mmap: postponing remap_vmalloc_range\n");
 242
 243                 mem->vma=kmalloc(sizeof(*vma),GFP_KERNEL);
 244                 if (!mem->vma) {
 245                         kfree(map);
 246                         q->bufs[first]->map=NULL;
 247                         return -ENOMEM;
 248                 }
 249                 memcpy(mem->vma,vma,sizeof(*vma));
 250         }
 251
 252         dprintk(1,"mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
 253                 map,q,vma->vm_start,vma->vm_end,
 254                 (long int) q->bufs[first]->bsize,
 255                 vma->vm_pgoff,first);
 256
 257         videobuf_vm_open(vma);
 258
 259         return (0);
 260 }
 261
 262 static int __videobuf_copy_to_user ( struct videobuf_queue *q,
 263                                 char __user *data, size_t count,
 264                                 int nonblocking )
 265 {
 266         struct videobuf_vmalloc_memory *mem=q->read_buf->priv;
 267         BUG_ON (!mem);
 268         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 269
 270         BUG_ON (!mem->vmalloc);
 271
 272         /* copy to userspace */
 273         if (count > q->read_buf->size - q->read_off)
 274                 count = q->read_buf->size - q->read_off;
 275
 276         if (copy_to_user(data, mem->vmalloc+q->read_off, count))
 277                 return -EFAULT;
 278
 279         return count;
 280 }
 281
 282 static int __videobuf_copy_stream ( struct videobuf_queue *q,
 283                                 char __user *data, size_t count, size_t pos,
 284                                 int vbihack, int nonblocking )
 285 {
 286         unsigned int  *fc;
 287         struct videobuf_vmalloc_memory *mem=q->read_buf->priv;
 288         BUG_ON (!mem);
 289         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 290
 291         if (vbihack) {
 292                 /* dirty, undocumented hack -- pass the frame counter
 293                         * within the last four bytes of each vbi data block.
 294                         * We need that one to maintain backward compatibility
 295                         * to all vbi decoding software out there ... */
 296                 fc  = (unsigned int*)mem->vmalloc;
 297                 fc += (q->read_buf->size>>2) -1;
 298                 *fc = q->read_buf->field_count >> 1;
 299                 dprintk(1,"vbihack: %d\n",*fc);
 300         }
 301
 302         /* copy stuff using the common method */
 303         count = __videobuf_copy_to_user (q,data,count,nonblocking);
 304
 305         if ( (count==-EFAULT) && (0 == pos) )
 306                 return -EFAULT;
 307
 308         return count;
 309 }
 310
 311 static struct videobuf_qtype_ops qops = {
 312         .magic        = MAGIC_QTYPE_OPS,
 313
 314         .alloc        = __videobuf_alloc,
 315         .iolock       = __videobuf_iolock,
 316         .sync         = __videobuf_sync,
 317         .mmap_free    = __videobuf_mmap_free,
 318         .mmap_mapper  = __videobuf_mmap_mapper,
 319         .video_copy_to_user = __videobuf_copy_to_user,
 320         .copy_stream  = __videobuf_copy_stream,
 321 };
 322
 323 void videobuf_queue_vmalloc_init(struct videobuf_queue* q,
 324                          struct videobuf_queue_ops *ops,
 325                          void *dev,
 326                          spinlock_t *irqlock,
 327                          enum v4l2_buf_type type,
 328                          enum v4l2_field field,
 329                          unsigned int msize,
 330                          void *priv)
 331 {
 332         videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
 333                                  priv, &qops);
 334 }
 335
 336 EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);
 337
 338 void *videobuf_to_vmalloc (struct videobuf_buffer *buf)
 339 {
 340         struct videobuf_vmalloc_memory *mem=buf->priv;
 341         BUG_ON (!mem);
 342         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 343
 344         return mem->vmalloc;
 345 }
 346 EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);
 347
 348 void videobuf_vmalloc_free (struct videobuf_buffer *buf)
 349 {
 350         struct videobuf_vmalloc_memory *mem=buf->priv;
 351         BUG_ON (!mem);
 352
 353         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
 354
 355         vfree(mem->vmalloc);
 356         mem->vmalloc=NULL;
 357
 358         return;
 359 }
 360 EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);
 361
 362 /*
 363  * Local variables:
 364  * c-basic-offset: 8
 365  * End:
 366  */