2 * helper functions for PCI DMA video4linux capture buffers
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.
9 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
11 * Highly based on video-buf written originally by:
12 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
13 * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
14 * (c) 2006 Ted Walther and John Sokol
16 * This program is free software; you can redistribute it and/or modify
17 * it under the terms of the GNU General Public License as published by
18 * the Free Software Foundation; either version 2
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/slab.h>
25 #include <linux/interrupt.h>
27 #include <linux/pci.h>
28 #include <linux/vmalloc.h>
29 #include <linux/pagemap.h>
31 #include <asm/pgtable.h>
33 #include <media/videobuf-dma-sg.h>
35 #define MAGIC_DMABUF 0x19721112
36 #define MAGIC_SG_MEM 0x17890714
38 #define MAGIC_CHECK(is,should) if (unlikely((is) != (should))) \
39 { printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); }
42 module_param(debug
, int, 0644);
44 MODULE_DESCRIPTION("helper module to manage video4linux pci dma sg buffers");
45 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
46 MODULE_LICENSE("GPL");
48 #define dprintk(level, fmt, arg...) if (debug >= level) \
49 printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
51 /* --------------------------------------------------------------------- */
54 videobuf_vmalloc_to_sg(unsigned char *virt
, int nr_pages
)
56 struct scatterlist
*sglist
;
60 sglist
= kcalloc(nr_pages
, sizeof(struct scatterlist
), GFP_KERNEL
);
63 for (i
= 0; i
< nr_pages
; i
++, virt
+= PAGE_SIZE
) {
64 pg
= vmalloc_to_page(virt
);
67 BUG_ON(PageHighMem(pg
));
69 sglist
[i
].length
= PAGE_SIZE
;
79 videobuf_pages_to_sg(struct page
**pages
, int nr_pages
, int offset
)
81 struct scatterlist
*sglist
;
86 sglist
= kcalloc(nr_pages
, sizeof(*sglist
), GFP_KERNEL
);
92 if (PageHighMem(pages
[0]))
93 /* DMA to highmem pages might not work */
95 sglist
[0].page
= pages
[0];
96 sglist
[0].offset
= offset
;
97 sglist
[0].length
= PAGE_SIZE
- offset
;
98 for (i
= 1; i
< nr_pages
; i
++) {
101 if (PageHighMem(pages
[i
]))
103 sglist
[i
].page
= pages
[i
];
104 sglist
[i
].length
= PAGE_SIZE
;
109 dprintk(2,"sgl: oops - no page\n");
114 dprintk(2,"sgl: oops - highmem page\n");
119 /* --------------------------------------------------------------------- */
121 struct videobuf_dmabuf
*videobuf_to_dma (struct videobuf_buffer
*buf
)
123 struct videbuf_pci_sg_memory
*mem
=buf
->priv
;
126 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
131 void videobuf_dma_init(struct videobuf_dmabuf
*dma
)
133 memset(dma
,0,sizeof(*dma
));
134 dma
->magic
= MAGIC_DMABUF
;
137 static int videobuf_dma_init_user_locked(struct videobuf_dmabuf
*dma
,
138 int direction
, unsigned long data
, unsigned long size
)
140 unsigned long first
,last
;
143 dma
->direction
= direction
;
144 switch (dma
->direction
) {
145 case PCI_DMA_FROMDEVICE
: rw
= READ
; break;
146 case PCI_DMA_TODEVICE
: rw
= WRITE
; break;
150 first
= (data
& PAGE_MASK
) >> PAGE_SHIFT
;
151 last
= ((data
+size
-1) & PAGE_MASK
) >> PAGE_SHIFT
;
152 dma
->offset
= data
& ~PAGE_MASK
;
153 dma
->nr_pages
= last
-first
+1;
154 dma
->pages
= kmalloc(dma
->nr_pages
* sizeof(struct page
*),
156 if (NULL
== dma
->pages
)
158 dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
159 data
,size
,dma
->nr_pages
);
161 dma
->varea
= (void *) data
;
164 err
= get_user_pages(current
,current
->mm
,
165 data
& PAGE_MASK
, dma
->nr_pages
,
166 rw
== READ
, 1, /* force */
169 if (err
!= dma
->nr_pages
) {
170 dma
->nr_pages
= (err
>= 0) ? err
: 0;
171 dprintk(1,"get_user_pages: err=%d [%d]\n",err
,dma
->nr_pages
);
172 return err
< 0 ? err
: -EINVAL
;
177 int videobuf_dma_init_user(struct videobuf_dmabuf
*dma
, int direction
,
178 unsigned long data
, unsigned long size
)
181 down_read(¤t
->mm
->mmap_sem
);
182 ret
= videobuf_dma_init_user_locked(dma
, direction
, data
, size
);
183 up_read(¤t
->mm
->mmap_sem
);
188 int videobuf_dma_init_kernel(struct videobuf_dmabuf
*dma
, int direction
,
191 dprintk(1,"init kernel [%d pages]\n",nr_pages
);
192 dma
->direction
= direction
;
193 dma
->vmalloc
= vmalloc_32(nr_pages
<< PAGE_SHIFT
);
194 if (NULL
== dma
->vmalloc
) {
195 dprintk(1,"vmalloc_32(%d pages) failed\n",nr_pages
);
198 dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
199 (unsigned long)dma
->vmalloc
,
200 nr_pages
<< PAGE_SHIFT
);
201 memset(dma
->vmalloc
,0,nr_pages
<< PAGE_SHIFT
);
202 dma
->nr_pages
= nr_pages
;
206 int videobuf_dma_init_overlay(struct videobuf_dmabuf
*dma
, int direction
,
207 dma_addr_t addr
, int nr_pages
)
209 dprintk(1,"init overlay [%d pages @ bus 0x%lx]\n",
210 nr_pages
,(unsigned long)addr
);
211 dma
->direction
= direction
;
215 dma
->bus_addr
= addr
;
216 dma
->nr_pages
= nr_pages
;
220 int videobuf_dma_map(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
)
224 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
225 BUG_ON(0 == dma
->nr_pages
);
228 dma
->sglist
= videobuf_pages_to_sg(dma
->pages
, dma
->nr_pages
,
232 dma
->sglist
= videobuf_vmalloc_to_sg
233 (dma
->vmalloc
,dma
->nr_pages
);
236 dma
->sglist
= kmalloc(sizeof(struct scatterlist
), GFP_KERNEL
);
237 if (NULL
!= dma
->sglist
) {
239 sg_dma_address(&dma
->sglist
[0]) = dma
->bus_addr
& PAGE_MASK
;
240 dma
->sglist
[0].offset
= dma
->bus_addr
& ~PAGE_MASK
;
241 sg_dma_len(&dma
->sglist
[0]) = dma
->nr_pages
* PAGE_SIZE
;
244 if (NULL
== dma
->sglist
) {
245 dprintk(1,"scatterlist is NULL\n");
248 if (!dma
->bus_addr
) {
249 dma
->sglen
= pci_map_sg(dev
,dma
->sglist
,
250 dma
->nr_pages
, dma
->direction
);
251 if (0 == dma
->sglen
) {
253 "%s: videobuf_map_sg failed\n",__FUNCTION__
);
263 int videobuf_dma_sync(struct videobuf_queue
*q
,struct videobuf_dmabuf
*dma
)
267 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
270 pci_dma_sync_sg_for_cpu (dev
,dma
->sglist
,dma
->nr_pages
,dma
->direction
);
274 int videobuf_dma_unmap(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
)
278 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
282 pci_unmap_sg (dev
,dma
->sglist
,dma
->nr_pages
,dma
->direction
);
290 int videobuf_dma_free(struct videobuf_dmabuf
*dma
)
292 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
297 for (i
=0; i
< dma
->nr_pages
; i
++)
298 page_cache_release(dma
->pages
[i
]);
310 dma
->direction
= PCI_DMA_NONE
;
314 /* --------------------------------------------------------------------- */
316 int videobuf_pci_dma_map(struct pci_dev
*pci
,struct videobuf_dmabuf
*dma
)
318 struct videobuf_queue q
;
322 return (videobuf_dma_map(&q
,dma
));
325 int videobuf_pci_dma_unmap(struct pci_dev
*pci
,struct videobuf_dmabuf
*dma
)
327 struct videobuf_queue q
;
331 return (videobuf_dma_unmap(&q
,dma
));
334 /* --------------------------------------------------------------------- */
337 videobuf_vm_open(struct vm_area_struct
*vma
)
339 struct videobuf_mapping
*map
= vma
->vm_private_data
;
341 dprintk(2,"vm_open %p [count=%d,vma=%08lx-%08lx]\n",map
,
342 map
->count
,vma
->vm_start
,vma
->vm_end
);
347 videobuf_vm_close(struct vm_area_struct
*vma
)
349 struct videobuf_mapping
*map
= vma
->vm_private_data
;
350 struct videobuf_queue
*q
= map
->q
;
351 struct videbuf_pci_sg_memory
*mem
;
354 dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map
,
355 map
->count
,vma
->vm_start
,vma
->vm_end
);
358 if (0 == map
->count
) {
359 dprintk(1,"munmap %p q=%p\n",map
,q
);
360 mutex_lock(&q
->lock
);
361 for (i
= 0; i
< VIDEO_MAX_FRAME
; i
++) {
362 if (NULL
== q
->bufs
[i
])
364 mem
=q
->bufs
[i
]->priv
;
369 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
371 if (q
->bufs
[i
]->map
!= map
)
373 q
->bufs
[i
]->map
= NULL
;
374 q
->bufs
[i
]->baddr
= 0;
375 q
->ops
->buf_release(q
,q
->bufs
[i
]);
377 mutex_unlock(&q
->lock
);
384 * Get a anonymous page for the mapping. Make sure we can DMA to that
385 * memory location with 32bit PCI devices (i.e. don't use highmem for
386 * now ...). Bounce buffers don't work very well for the data rates
390 videobuf_vm_nopage(struct vm_area_struct
*vma
, unsigned long vaddr
,
395 dprintk(3,"nopage: fault @ %08lx [vma %08lx-%08lx]\n",
396 vaddr
,vma
->vm_start
,vma
->vm_end
);
397 if (vaddr
> vma
->vm_end
)
398 return NOPAGE_SIGBUS
;
399 page
= alloc_page(GFP_USER
| __GFP_DMA32
);
402 clear_user_page(page_address(page
), vaddr
, page
);
404 *type
= VM_FAULT_MINOR
;
408 static struct vm_operations_struct videobuf_vm_ops
=
410 .open
= videobuf_vm_open
,
411 .close
= videobuf_vm_close
,
412 .nopage
= videobuf_vm_nopage
,
415 /* ---------------------------------------------------------------------
416 * PCI handlers for the generic methods
419 /* Allocated area consists on 3 parts:
421 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
422 struct videobuf_pci_sg_memory
425 static void *__videobuf_alloc(size_t size
)
427 struct videbuf_pci_sg_memory
*mem
;
428 struct videobuf_buffer
*vb
;
430 vb
= kzalloc(size
+sizeof(*mem
),GFP_KERNEL
);
432 mem
= vb
->priv
= ((char *)vb
)+size
;
433 mem
->magic
=MAGIC_SG_MEM
;
435 videobuf_dma_init(&mem
->dma
);
437 dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
438 __FUNCTION__
,vb
,(long)sizeof(*vb
),(long)size
-sizeof(*vb
),
439 mem
,(long)sizeof(*mem
));
444 static int __videobuf_iolock (struct videobuf_queue
* q
,
445 struct videobuf_buffer
*vb
,
446 struct v4l2_framebuffer
*fbuf
)
450 struct videbuf_pci_sg_memory
*mem
=vb
->priv
;
453 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
455 switch (vb
->memory
) {
456 case V4L2_MEMORY_MMAP
:
457 case V4L2_MEMORY_USERPTR
:
458 if (0 == vb
->baddr
) {
459 /* no userspace addr -- kernel bounce buffer */
460 pages
= PAGE_ALIGN(vb
->size
) >> PAGE_SHIFT
;
461 err
= videobuf_dma_init_kernel( &mem
->dma
,
466 } else if (vb
->memory
== V4L2_MEMORY_USERPTR
) {
467 /* dma directly to userspace */
468 err
= videobuf_dma_init_user( &mem
->dma
,
470 vb
->baddr
,vb
->bsize
);
474 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
475 buffers can only be called from videobuf_qbuf
476 we take current->mm->mmap_sem there, to prevent
477 locking inversion, so don't take it here */
479 err
= videobuf_dma_init_user_locked(&mem
->dma
,
481 vb
->baddr
, vb
->bsize
);
486 case V4L2_MEMORY_OVERLAY
:
489 /* FIXME: need sanity checks for vb->boff */
491 * Using a double cast to avoid compiler warnings when
492 * building for PAE. Compiler doesn't like direct casting
493 * of a 32 bit ptr to 64 bit integer.
495 bus
= (dma_addr_t
)(unsigned long)fbuf
->base
+ vb
->boff
;
496 pages
= PAGE_ALIGN(vb
->size
) >> PAGE_SHIFT
;
497 err
= videobuf_dma_init_overlay(&mem
->dma
,PCI_DMA_FROMDEVICE
,
505 err
= videobuf_dma_map(q
,&mem
->dma
);
512 static int __videobuf_sync(struct videobuf_queue
*q
,
513 struct videobuf_buffer
*buf
)
515 struct videbuf_pci_sg_memory
*mem
=buf
->priv
;
517 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
519 return videobuf_dma_sync(q
,&mem
->dma
);
522 static int __videobuf_mmap_free(struct videobuf_queue
*q
)
526 for (i
= 0; i
< VIDEO_MAX_FRAME
; i
++) {
536 static int __videobuf_mmap_mapper(struct videobuf_queue
*q
,
537 struct vm_area_struct
*vma
)
539 struct videbuf_pci_sg_memory
*mem
;
540 struct videobuf_mapping
*map
;
541 unsigned int first
,last
,size
,i
;
545 if (!(vma
->vm_flags
& VM_WRITE
)) {
546 dprintk(1,"mmap app bug: PROT_WRITE please\n");
549 if (!(vma
->vm_flags
& VM_SHARED
)) {
550 dprintk(1,"mmap app bug: MAP_SHARED please\n");
554 /* look for first buffer to map */
555 for (first
= 0; first
< VIDEO_MAX_FRAME
; first
++) {
556 if (NULL
== q
->bufs
[first
])
558 mem
=q
->bufs
[first
]->priv
;
560 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
562 if (V4L2_MEMORY_MMAP
!= q
->bufs
[first
]->memory
)
564 if (q
->bufs
[first
]->boff
== (vma
->vm_pgoff
<< PAGE_SHIFT
))
567 if (VIDEO_MAX_FRAME
== first
) {
568 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
569 (vma
->vm_pgoff
<< PAGE_SHIFT
));
573 /* look for last buffer to map */
574 for (size
= 0, last
= first
; last
< VIDEO_MAX_FRAME
; last
++) {
575 if (NULL
== q
->bufs
[last
])
577 if (V4L2_MEMORY_MMAP
!= q
->bufs
[last
]->memory
)
579 if (q
->bufs
[last
]->map
) {
583 size
+= q
->bufs
[last
]->bsize
;
584 if (size
== (vma
->vm_end
- vma
->vm_start
))
587 if (VIDEO_MAX_FRAME
== last
) {
588 dprintk(1,"mmap app bug: size invalid [size=0x%lx]\n",
589 (vma
->vm_end
- vma
->vm_start
));
593 /* create mapping + update buffer list */
595 map
= kmalloc(sizeof(struct videobuf_mapping
),GFP_KERNEL
);
598 for (size
= 0, i
= first
; i
<= last
; size
+= q
->bufs
[i
++]->bsize
) {
599 q
->bufs
[i
]->map
= map
;
600 q
->bufs
[i
]->baddr
= vma
->vm_start
+ size
;
603 map
->start
= vma
->vm_start
;
604 map
->end
= vma
->vm_end
;
606 vma
->vm_ops
= &videobuf_vm_ops
;
607 vma
->vm_flags
|= VM_DONTEXPAND
| VM_RESERVED
;
608 vma
->vm_flags
&= ~VM_IO
; /* using shared anonymous pages */
609 vma
->vm_private_data
= map
;
610 dprintk(1,"mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
611 map
,q
,vma
->vm_start
,vma
->vm_end
,vma
->vm_pgoff
,first
,last
);
618 static int __videobuf_copy_to_user ( struct videobuf_queue
*q
,
619 char __user
*data
, size_t count
,
622 struct videbuf_pci_sg_memory
*mem
=q
->read_buf
->priv
;
624 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
626 /* copy to userspace */
627 if (count
> q
->read_buf
->size
- q
->read_off
)
628 count
= q
->read_buf
->size
- q
->read_off
;
630 if (copy_to_user(data
, mem
->dma
.vmalloc
+q
->read_off
, count
))
636 static int __videobuf_copy_stream ( struct videobuf_queue
*q
,
637 char __user
*data
, size_t count
, size_t pos
,
638 int vbihack
, int nonblocking
)
641 struct videbuf_pci_sg_memory
*mem
=q
->read_buf
->priv
;
643 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
646 /* dirty, undocumented hack -- pass the frame counter
647 * within the last four bytes of each vbi data block.
648 * We need that one to maintain backward compatibility
649 * to all vbi decoding software out there ... */
650 fc
= (unsigned int*)mem
->dma
.vmalloc
;
651 fc
+= (q
->read_buf
->size
>>2) -1;
652 *fc
= q
->read_buf
->field_count
>> 1;
653 dprintk(1,"vbihack: %d\n",*fc
);
656 /* copy stuff using the common method */
657 count
= __videobuf_copy_to_user (q
,data
,count
,nonblocking
);
659 if ( (count
==-EFAULT
) && (0 == pos
) )
665 static struct videobuf_qtype_ops pci_ops
= {
666 .magic
= MAGIC_QTYPE_OPS
,
668 .alloc
= __videobuf_alloc
,
669 .iolock
= __videobuf_iolock
,
670 .sync
= __videobuf_sync
,
671 .mmap_free
= __videobuf_mmap_free
,
672 .mmap_mapper
= __videobuf_mmap_mapper
,
673 .copy_to_user
= __videobuf_copy_to_user
,
674 .copy_stream
= __videobuf_copy_stream
,
677 void *videobuf_pci_alloc (size_t size
)
679 struct videobuf_queue q
;
681 /* Required to make generic handler to call __videobuf_alloc */
686 return videobuf_alloc (&q
);
689 void videobuf_queue_pci_init(struct videobuf_queue
* q
,
690 struct videobuf_queue_ops
*ops
,
693 enum v4l2_buf_type type
,
694 enum v4l2_field field
,
698 videobuf_queue_core_init(q
, ops
, dev
, irqlock
, type
, field
, msize
,
702 /* --------------------------------------------------------------------- */
704 EXPORT_SYMBOL_GPL(videobuf_vmalloc_to_sg
);
706 EXPORT_SYMBOL_GPL(videobuf_to_dma
);
707 EXPORT_SYMBOL_GPL(videobuf_dma_init
);
708 EXPORT_SYMBOL_GPL(videobuf_dma_init_user
);
709 EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel
);
710 EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay
);
711 EXPORT_SYMBOL_GPL(videobuf_dma_map
);
712 EXPORT_SYMBOL_GPL(videobuf_dma_sync
);
713 EXPORT_SYMBOL_GPL(videobuf_dma_unmap
);
714 EXPORT_SYMBOL_GPL(videobuf_dma_free
);
716 EXPORT_SYMBOL_GPL(videobuf_pci_dma_map
);
717 EXPORT_SYMBOL_GPL(videobuf_pci_dma_unmap
);
718 EXPORT_SYMBOL_GPL(videobuf_pci_alloc
);
720 EXPORT_SYMBOL_GPL(videobuf_queue_pci_init
);