V4L/DVB (7241): cx25840: code cleanup
[linux-2.6] / 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 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->ops->buf_release(q,q->bufs[i]);
82
83                         q->bufs[i]->map   = NULL;
84                         q->bufs[i]->baddr = 0;
85                 }
86                 mutex_unlock(&q->vb_lock);
87                 kfree(map);
88         }
89         return;
90 }
91
92 static struct vm_operations_struct videobuf_vm_ops =
93 {
94         .open     = videobuf_vm_open,
95         .close    = videobuf_vm_close,
96 };
97
98 /* ---------------------------------------------------------------------
99  * vmalloc handlers for the generic methods
100  */
101
102 /* Allocated area consists on 3 parts:
103         struct video_buffer
104         struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
105         struct videobuf_dma_sg_memory
106  */
107
108 static void *__videobuf_alloc(size_t size)
109 {
110         struct videobuf_vmalloc_memory *mem;
111         struct videobuf_buffer *vb;
112
113         vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
114
115         mem = vb->priv = ((char *)vb)+size;
116         mem->magic=MAGIC_VMAL_MEM;
117
118         dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
119                 __FUNCTION__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb),
120                 mem,(long)sizeof(*mem));
121
122         return vb;
123 }
124
125 static int __videobuf_iolock (struct videobuf_queue* q,
126                               struct videobuf_buffer *vb,
127                               struct v4l2_framebuffer *fbuf)
128 {
129         int pages;
130         struct videobuf_vmalloc_memory *mem=vb->priv;
131
132         BUG_ON(!mem);
133
134         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
135
136         pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
137
138         /* Currently, doesn't support V4L2_MEMORY_OVERLAY */
139         if ((vb->memory != V4L2_MEMORY_MMAP) &&
140                                 (vb->memory != V4L2_MEMORY_USERPTR) ) {
141                 printk(KERN_ERR "Method currently unsupported.\n");
142                 return -EINVAL;
143         }
144
145         /* FIXME: should be tested with kernel mmap mem */
146         mem->vmalloc=vmalloc_user (PAGE_ALIGN(vb->size));
147         if (NULL == mem->vmalloc) {
148                 printk(KERN_ERR "vmalloc (%d pages) failed\n",pages);
149                 return -ENOMEM;
150         }
151
152         dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
153                                 (unsigned long)mem->vmalloc,
154                                 pages << PAGE_SHIFT);
155
156         /* It seems that some kernel versions need to do remap *after*
157            the mmap() call
158          */
159         if (mem->vma) {
160                 int retval=remap_vmalloc_range(mem->vma, mem->vmalloc,0);
161                 kfree(mem->vma);
162                 mem->vma=NULL;
163                 if (retval<0) {
164                         dprintk(1,"mmap app bug: remap_vmalloc_range area %p error %d\n",
165                                 mem->vmalloc,retval);
166                         return retval;
167                 }
168         }
169
170         return 0;
171 }
172
173 static int __videobuf_sync(struct videobuf_queue *q,
174                            struct videobuf_buffer *buf)
175 {
176         return 0;
177 }
178
179 static int __videobuf_mmap_free(struct videobuf_queue *q)
180 {
181         unsigned int i;
182
183         for (i = 0; i < VIDEO_MAX_FRAME; i++) {
184                 if (q->bufs[i]) {
185                         if (q->bufs[i]->map)
186                                 return -EBUSY;
187                 }
188         }
189
190         return 0;
191 }
192
193 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
194                          struct vm_area_struct *vma)
195 {
196         struct videobuf_vmalloc_memory *mem;
197         struct videobuf_mapping *map;
198         unsigned int first;
199         int retval;
200         unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
201
202         if (! (vma->vm_flags & VM_WRITE) || ! (vma->vm_flags & VM_SHARED))
203                 return -EINVAL;
204
205         /* look for first buffer to map */
206         for (first = 0; first < VIDEO_MAX_FRAME; first++) {
207                 if (NULL == q->bufs[first])
208                         continue;
209
210                 if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
211                         continue;
212                 if (q->bufs[first]->boff == offset)
213                         break;
214         }
215         if (VIDEO_MAX_FRAME == first) {
216                 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
217                         (vma->vm_pgoff << PAGE_SHIFT));
218                 return -EINVAL;
219         }
220
221         /* create mapping + update buffer list */
222         map = q->bufs[first]->map = kzalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
223         if (NULL == map)
224                 return -ENOMEM;
225
226         map->start = vma->vm_start;
227         map->end   = vma->vm_end;
228         map->q     = q;
229
230         q->bufs[first]->baddr = vma->vm_start;
231
232         vma->vm_ops          = &videobuf_vm_ops;
233         vma->vm_flags       |= VM_DONTEXPAND | VM_RESERVED;
234         vma->vm_private_data = map;
235
236         mem=q->bufs[first]->priv;
237         BUG_ON (!mem);
238         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
239
240         /* Try to remap memory */
241         retval=remap_vmalloc_range(vma, mem->vmalloc,0);
242         if (retval<0) {
243                 dprintk(1,"mmap: postponing remap_vmalloc_range\n");
244
245                 mem->vma=kmalloc(sizeof(*vma),GFP_KERNEL);
246                 if (!mem->vma) {
247                         kfree(map);
248                         q->bufs[first]->map=NULL;
249                         return -ENOMEM;
250                 }
251                 memcpy(mem->vma,vma,sizeof(*vma));
252         }
253
254         dprintk(1,"mmap %p: q=%p %08lx-%08lx (%lx) pgoff %08lx buf %d\n",
255                 map,q,vma->vm_start,vma->vm_end,
256                 (long int) q->bufs[first]->bsize,
257                 vma->vm_pgoff,first);
258
259         videobuf_vm_open(vma);
260
261         return (0);
262 }
263
264 static int __videobuf_copy_to_user ( struct videobuf_queue *q,
265                                 char __user *data, size_t count,
266                                 int nonblocking )
267 {
268         struct videobuf_vmalloc_memory *mem=q->read_buf->priv;
269         BUG_ON (!mem);
270         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
271
272         BUG_ON (!mem->vmalloc);
273
274         /* copy to userspace */
275         if (count > q->read_buf->size - q->read_off)
276                 count = q->read_buf->size - q->read_off;
277
278         if (copy_to_user(data, mem->vmalloc+q->read_off, count))
279                 return -EFAULT;
280
281         return count;
282 }
283
284 static int __videobuf_copy_stream ( struct videobuf_queue *q,
285                                 char __user *data, size_t count, size_t pos,
286                                 int vbihack, int nonblocking )
287 {
288         unsigned int  *fc;
289         struct videobuf_vmalloc_memory *mem=q->read_buf->priv;
290         BUG_ON (!mem);
291         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
292
293         if (vbihack) {
294                 /* dirty, undocumented hack -- pass the frame counter
295                         * within the last four bytes of each vbi data block.
296                         * We need that one to maintain backward compatibility
297                         * to all vbi decoding software out there ... */
298                 fc  = (unsigned int*)mem->vmalloc;
299                 fc += (q->read_buf->size>>2) -1;
300                 *fc = q->read_buf->field_count >> 1;
301                 dprintk(1,"vbihack: %d\n",*fc);
302         }
303
304         /* copy stuff using the common method */
305         count = __videobuf_copy_to_user (q,data,count,nonblocking);
306
307         if ( (count==-EFAULT) && (0 == pos) )
308                 return -EFAULT;
309
310         return count;
311 }
312
313 static struct videobuf_qtype_ops qops = {
314         .magic        = MAGIC_QTYPE_OPS,
315
316         .alloc        = __videobuf_alloc,
317         .iolock       = __videobuf_iolock,
318         .sync         = __videobuf_sync,
319         .mmap_free    = __videobuf_mmap_free,
320         .mmap_mapper  = __videobuf_mmap_mapper,
321         .video_copy_to_user = __videobuf_copy_to_user,
322         .copy_stream  = __videobuf_copy_stream,
323 };
324
325 void videobuf_queue_vmalloc_init(struct videobuf_queue* q,
326                          struct videobuf_queue_ops *ops,
327                          void *dev,
328                          spinlock_t *irqlock,
329                          enum v4l2_buf_type type,
330                          enum v4l2_field field,
331                          unsigned int msize,
332                          void *priv)
333 {
334         videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
335                                  priv, &qops);
336 }
337
338 EXPORT_SYMBOL_GPL(videobuf_queue_vmalloc_init);
339
340 void *videobuf_to_vmalloc (struct videobuf_buffer *buf)
341 {
342         struct videobuf_vmalloc_memory *mem=buf->priv;
343         BUG_ON (!mem);
344         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
345
346         return mem->vmalloc;
347 }
348 EXPORT_SYMBOL_GPL(videobuf_to_vmalloc);
349
350 void videobuf_vmalloc_free (struct videobuf_buffer *buf)
351 {
352         struct videobuf_vmalloc_memory *mem=buf->priv;
353         BUG_ON (!mem);
354
355         MAGIC_CHECK(mem->magic,MAGIC_VMAL_MEM);
356
357         vfree(mem->vmalloc);
358         mem->vmalloc=NULL;
359
360         return;
361 }
362 EXPORT_SYMBOL_GPL(videobuf_vmalloc_free);
363
364 /*
365  * Local variables:
366  * c-basic-offset: 8
367  * End:
368  */