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>
30 #include <linux/scatterlist.h>
32 #include <asm/pgtable.h>
34 #include <media/videobuf-dma-sg.h>
36 #define MAGIC_DMABUF 0x19721112
37 #define MAGIC_SG_MEM 0x17890714
39 #define MAGIC_CHECK(is,should) if (unlikely((is) != (should))) \
40 { printk(KERN_ERR "magic mismatch: %x (expected %x)\n",is,should); BUG(); }
43 module_param(debug
, int, 0644);
45 MODULE_DESCRIPTION("helper module to manage video4linux pci dma sg buffers");
46 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
47 MODULE_LICENSE("GPL");
49 #define dprintk(level, fmt, arg...) if (debug >= level) \
50 printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
52 /* --------------------------------------------------------------------- */
55 videobuf_vmalloc_to_sg(unsigned char *virt
, int nr_pages
)
57 struct scatterlist
*sglist
;
61 sglist
= kcalloc(nr_pages
, sizeof(struct scatterlist
), GFP_KERNEL
);
64 sg_init_table(sglist
, nr_pages
);
65 for (i
= 0; i
< nr_pages
; i
++, virt
+= PAGE_SIZE
) {
66 pg
= vmalloc_to_page(virt
);
69 BUG_ON(PageHighMem(pg
));
70 sg_set_page(&sglist
[i
], pg
, PAGE_SIZE
, 0);
80 videobuf_pages_to_sg(struct page
**pages
, int nr_pages
, int offset
)
82 struct scatterlist
*sglist
;
87 sglist
= kcalloc(nr_pages
, sizeof(*sglist
), GFP_KERNEL
);
90 sg_init_table(sglist
, nr_pages
);
94 if (PageHighMem(pages
[0]))
95 /* DMA to highmem pages might not work */
97 sg_set_page(&sglist
[0], pages
[0], PAGE_SIZE
- offset
, offset
);
98 for (i
= 1; i
< nr_pages
; i
++) {
101 if (PageHighMem(pages
[i
]))
103 sg_set_page(&sglist
[i
], pages
[i
], PAGE_SIZE
, 0);
108 dprintk(2,"sgl: oops - no page\n");
113 dprintk(2,"sgl: oops - highmem page\n");
118 /* --------------------------------------------------------------------- */
120 struct videobuf_dmabuf
*videobuf_to_dma (struct videobuf_buffer
*buf
)
122 struct videbuf_pci_sg_memory
*mem
=buf
->priv
;
125 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
130 void videobuf_dma_init(struct videobuf_dmabuf
*dma
)
132 memset(dma
,0,sizeof(*dma
));
133 dma
->magic
= MAGIC_DMABUF
;
136 static int videobuf_dma_init_user_locked(struct videobuf_dmabuf
*dma
,
137 int direction
, unsigned long data
, unsigned long size
)
139 unsigned long first
,last
;
142 dma
->direction
= direction
;
143 switch (dma
->direction
) {
144 case PCI_DMA_FROMDEVICE
: rw
= READ
; break;
145 case PCI_DMA_TODEVICE
: rw
= WRITE
; break;
149 first
= (data
& PAGE_MASK
) >> PAGE_SHIFT
;
150 last
= ((data
+size
-1) & PAGE_MASK
) >> PAGE_SHIFT
;
151 dma
->offset
= data
& ~PAGE_MASK
;
152 dma
->nr_pages
= last
-first
+1;
153 dma
->pages
= kmalloc(dma
->nr_pages
* sizeof(struct page
*),
155 if (NULL
== dma
->pages
)
157 dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
158 data
,size
,dma
->nr_pages
);
160 dma
->varea
= (void *) data
;
163 err
= get_user_pages(current
,current
->mm
,
164 data
& PAGE_MASK
, dma
->nr_pages
,
165 rw
== READ
, 1, /* force */
168 if (err
!= dma
->nr_pages
) {
169 dma
->nr_pages
= (err
>= 0) ? err
: 0;
170 dprintk(1,"get_user_pages: err=%d [%d]\n",err
,dma
->nr_pages
);
171 return err
< 0 ? err
: -EINVAL
;
176 int videobuf_dma_init_user(struct videobuf_dmabuf
*dma
, int direction
,
177 unsigned long data
, unsigned long size
)
180 down_read(¤t
->mm
->mmap_sem
);
181 ret
= videobuf_dma_init_user_locked(dma
, direction
, data
, size
);
182 up_read(¤t
->mm
->mmap_sem
);
187 int videobuf_dma_init_kernel(struct videobuf_dmabuf
*dma
, int direction
,
190 dprintk(1,"init kernel [%d pages]\n",nr_pages
);
191 dma
->direction
= direction
;
192 dma
->vmalloc
= vmalloc_32(nr_pages
<< PAGE_SHIFT
);
193 if (NULL
== dma
->vmalloc
) {
194 dprintk(1,"vmalloc_32(%d pages) failed\n",nr_pages
);
197 dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
198 (unsigned long)dma
->vmalloc
,
199 nr_pages
<< PAGE_SHIFT
);
200 memset(dma
->vmalloc
,0,nr_pages
<< PAGE_SHIFT
);
201 dma
->nr_pages
= nr_pages
;
205 int videobuf_dma_init_overlay(struct videobuf_dmabuf
*dma
, int direction
,
206 dma_addr_t addr
, int nr_pages
)
208 dprintk(1,"init overlay [%d pages @ bus 0x%lx]\n",
209 nr_pages
,(unsigned long)addr
);
210 dma
->direction
= direction
;
214 dma
->bus_addr
= addr
;
215 dma
->nr_pages
= nr_pages
;
219 int videobuf_dma_map(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
)
223 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
224 BUG_ON(0 == dma
->nr_pages
);
227 dma
->sglist
= videobuf_pages_to_sg(dma
->pages
, dma
->nr_pages
,
231 dma
->sglist
= videobuf_vmalloc_to_sg
232 (dma
->vmalloc
,dma
->nr_pages
);
235 dma
->sglist
= kmalloc(sizeof(struct scatterlist
), GFP_KERNEL
);
236 if (NULL
!= dma
->sglist
) {
238 sg_dma_address(&dma
->sglist
[0]) = dma
->bus_addr
& PAGE_MASK
;
239 dma
->sglist
[0].offset
= dma
->bus_addr
& ~PAGE_MASK
;
240 sg_dma_len(&dma
->sglist
[0]) = dma
->nr_pages
* PAGE_SIZE
;
243 if (NULL
== dma
->sglist
) {
244 dprintk(1,"scatterlist is NULL\n");
247 if (!dma
->bus_addr
) {
248 dma
->sglen
= pci_map_sg(dev
,dma
->sglist
,
249 dma
->nr_pages
, dma
->direction
);
250 if (0 == dma
->sglen
) {
252 "%s: videobuf_map_sg failed\n",__FUNCTION__
);
262 int videobuf_dma_sync(struct videobuf_queue
*q
,struct videobuf_dmabuf
*dma
)
266 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
269 pci_dma_sync_sg_for_cpu (dev
,dma
->sglist
,dma
->nr_pages
,dma
->direction
);
273 int videobuf_dma_unmap(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
)
277 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
281 pci_unmap_sg (dev
,dma
->sglist
,dma
->nr_pages
,dma
->direction
);
289 int videobuf_dma_free(struct videobuf_dmabuf
*dma
)
291 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
296 for (i
=0; i
< dma
->nr_pages
; i
++)
297 page_cache_release(dma
->pages
[i
]);
309 dma
->direction
= PCI_DMA_NONE
;
313 /* --------------------------------------------------------------------- */
315 int videobuf_pci_dma_map(struct pci_dev
*pci
,struct videobuf_dmabuf
*dma
)
317 struct videobuf_queue q
;
321 return (videobuf_dma_map(&q
,dma
));
324 int videobuf_pci_dma_unmap(struct pci_dev
*pci
,struct videobuf_dmabuf
*dma
)
326 struct videobuf_queue q
;
330 return (videobuf_dma_unmap(&q
,dma
));
333 /* --------------------------------------------------------------------- */
336 videobuf_vm_open(struct vm_area_struct
*vma
)
338 struct videobuf_mapping
*map
= vma
->vm_private_data
;
340 dprintk(2,"vm_open %p [count=%d,vma=%08lx-%08lx]\n",map
,
341 map
->count
,vma
->vm_start
,vma
->vm_end
);
346 videobuf_vm_close(struct vm_area_struct
*vma
)
348 struct videobuf_mapping
*map
= vma
->vm_private_data
;
349 struct videobuf_queue
*q
= map
->q
;
350 struct videbuf_pci_sg_memory
*mem
;
353 dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map
,
354 map
->count
,vma
->vm_start
,vma
->vm_end
);
357 if (0 == map
->count
) {
358 dprintk(1,"munmap %p q=%p\n",map
,q
);
359 mutex_lock(&q
->vb_lock
);
360 for (i
= 0; i
< VIDEO_MAX_FRAME
; i
++) {
361 if (NULL
== q
->bufs
[i
])
363 mem
=q
->bufs
[i
]->priv
;
368 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
370 if (q
->bufs
[i
]->map
!= map
)
372 q
->bufs
[i
]->map
= NULL
;
373 q
->bufs
[i
]->baddr
= 0;
374 q
->ops
->buf_release(q
,q
->bufs
[i
]);
376 mutex_unlock(&q
->vb_lock
);
383 * Get a anonymous page for the mapping. Make sure we can DMA to that
384 * memory location with 32bit PCI devices (i.e. don't use highmem for
385 * now ...). Bounce buffers don't work very well for the data rates
389 videobuf_vm_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
393 dprintk(3,"fault: fault @ %08lx [vma %08lx-%08lx]\n",
394 (unsigned long)vmf
->virtual_address
,vma
->vm_start
,vma
->vm_end
);
395 page
= alloc_page(GFP_USER
| __GFP_DMA32
);
398 clear_user_page(page_address(page
), (unsigned long)vmf
->virtual_address
,
404 static struct vm_operations_struct videobuf_vm_ops
=
406 .open
= videobuf_vm_open
,
407 .close
= videobuf_vm_close
,
408 .fault
= videobuf_vm_fault
,
411 /* ---------------------------------------------------------------------
412 * PCI handlers for the generic methods
415 /* Allocated area consists on 3 parts:
417 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
418 struct videobuf_pci_sg_memory
421 static void *__videobuf_alloc(size_t size
)
423 struct videbuf_pci_sg_memory
*mem
;
424 struct videobuf_buffer
*vb
;
426 vb
= kzalloc(size
+sizeof(*mem
),GFP_KERNEL
);
428 mem
= vb
->priv
= ((char *)vb
)+size
;
429 mem
->magic
=MAGIC_SG_MEM
;
431 videobuf_dma_init(&mem
->dma
);
433 dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
434 __FUNCTION__
,vb
,(long)sizeof(*vb
),(long)size
-sizeof(*vb
),
435 mem
,(long)sizeof(*mem
));
440 static int __videobuf_iolock (struct videobuf_queue
* q
,
441 struct videobuf_buffer
*vb
,
442 struct v4l2_framebuffer
*fbuf
)
446 struct videbuf_pci_sg_memory
*mem
=vb
->priv
;
449 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
451 switch (vb
->memory
) {
452 case V4L2_MEMORY_MMAP
:
453 case V4L2_MEMORY_USERPTR
:
454 if (0 == vb
->baddr
) {
455 /* no userspace addr -- kernel bounce buffer */
456 pages
= PAGE_ALIGN(vb
->size
) >> PAGE_SHIFT
;
457 err
= videobuf_dma_init_kernel( &mem
->dma
,
462 } else if (vb
->memory
== V4L2_MEMORY_USERPTR
) {
463 /* dma directly to userspace */
464 err
= videobuf_dma_init_user( &mem
->dma
,
466 vb
->baddr
,vb
->bsize
);
470 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
471 buffers can only be called from videobuf_qbuf
472 we take current->mm->mmap_sem there, to prevent
473 locking inversion, so don't take it here */
475 err
= videobuf_dma_init_user_locked(&mem
->dma
,
477 vb
->baddr
, vb
->bsize
);
482 case V4L2_MEMORY_OVERLAY
:
485 /* FIXME: need sanity checks for vb->boff */
487 * Using a double cast to avoid compiler warnings when
488 * building for PAE. Compiler doesn't like direct casting
489 * of a 32 bit ptr to 64 bit integer.
491 bus
= (dma_addr_t
)(unsigned long)fbuf
->base
+ vb
->boff
;
492 pages
= PAGE_ALIGN(vb
->size
) >> PAGE_SHIFT
;
493 err
= videobuf_dma_init_overlay(&mem
->dma
,PCI_DMA_FROMDEVICE
,
501 err
= videobuf_dma_map(q
,&mem
->dma
);
508 static int __videobuf_sync(struct videobuf_queue
*q
,
509 struct videobuf_buffer
*buf
)
511 struct videbuf_pci_sg_memory
*mem
=buf
->priv
;
513 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
515 return videobuf_dma_sync(q
,&mem
->dma
);
518 static int __videobuf_mmap_free(struct videobuf_queue
*q
)
522 for (i
= 0; i
< VIDEO_MAX_FRAME
; i
++) {
532 static int __videobuf_mmap_mapper(struct videobuf_queue
*q
,
533 struct vm_area_struct
*vma
)
535 struct videbuf_pci_sg_memory
*mem
;
536 struct videobuf_mapping
*map
;
537 unsigned int first
,last
,size
,i
;
541 if (!(vma
->vm_flags
& VM_WRITE
)) {
542 dprintk(1,"mmap app bug: PROT_WRITE please\n");
545 if (!(vma
->vm_flags
& VM_SHARED
)) {
546 dprintk(1,"mmap app bug: MAP_SHARED please\n");
550 /* look for first buffer to map */
551 for (first
= 0; first
< VIDEO_MAX_FRAME
; first
++) {
552 if (NULL
== q
->bufs
[first
])
554 mem
=q
->bufs
[first
]->priv
;
556 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
558 if (V4L2_MEMORY_MMAP
!= q
->bufs
[first
]->memory
)
560 if (q
->bufs
[first
]->boff
== (vma
->vm_pgoff
<< PAGE_SHIFT
))
563 if (VIDEO_MAX_FRAME
== first
) {
564 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
565 (vma
->vm_pgoff
<< PAGE_SHIFT
));
569 /* look for last buffer to map */
570 for (size
= 0, last
= first
; last
< VIDEO_MAX_FRAME
; last
++) {
571 if (NULL
== q
->bufs
[last
])
573 if (V4L2_MEMORY_MMAP
!= q
->bufs
[last
]->memory
)
575 if (q
->bufs
[last
]->map
) {
579 size
+= q
->bufs
[last
]->bsize
;
580 if (size
== (vma
->vm_end
- vma
->vm_start
))
583 if (VIDEO_MAX_FRAME
== last
) {
584 dprintk(1,"mmap app bug: size invalid [size=0x%lx]\n",
585 (vma
->vm_end
- vma
->vm_start
));
589 /* create mapping + update buffer list */
591 map
= kmalloc(sizeof(struct videobuf_mapping
),GFP_KERNEL
);
594 for (size
= 0, i
= first
; i
<= last
; size
+= q
->bufs
[i
++]->bsize
) {
595 q
->bufs
[i
]->map
= map
;
596 q
->bufs
[i
]->baddr
= vma
->vm_start
+ size
;
599 map
->start
= vma
->vm_start
;
600 map
->end
= vma
->vm_end
;
602 vma
->vm_ops
= &videobuf_vm_ops
;
603 vma
->vm_flags
|= VM_DONTEXPAND
| VM_RESERVED
;
604 vma
->vm_flags
&= ~VM_IO
; /* using shared anonymous pages */
605 vma
->vm_private_data
= map
;
606 dprintk(1,"mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
607 map
,q
,vma
->vm_start
,vma
->vm_end
,vma
->vm_pgoff
,first
,last
);
614 static int __videobuf_copy_to_user ( struct videobuf_queue
*q
,
615 char __user
*data
, size_t count
,
618 struct videbuf_pci_sg_memory
*mem
=q
->read_buf
->priv
;
620 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
622 /* copy to userspace */
623 if (count
> q
->read_buf
->size
- q
->read_off
)
624 count
= q
->read_buf
->size
- q
->read_off
;
626 if (copy_to_user(data
, mem
->dma
.vmalloc
+q
->read_off
, count
))
632 static int __videobuf_copy_stream ( struct videobuf_queue
*q
,
633 char __user
*data
, size_t count
, size_t pos
,
634 int vbihack
, int nonblocking
)
637 struct videbuf_pci_sg_memory
*mem
=q
->read_buf
->priv
;
639 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
642 /* dirty, undocumented hack -- pass the frame counter
643 * within the last four bytes of each vbi data block.
644 * We need that one to maintain backward compatibility
645 * to all vbi decoding software out there ... */
646 fc
= (unsigned int*)mem
->dma
.vmalloc
;
647 fc
+= (q
->read_buf
->size
>>2) -1;
648 *fc
= q
->read_buf
->field_count
>> 1;
649 dprintk(1,"vbihack: %d\n",*fc
);
652 /* copy stuff using the common method */
653 count
= __videobuf_copy_to_user (q
,data
,count
,nonblocking
);
655 if ( (count
==-EFAULT
) && (0 == pos
) )
661 static struct videobuf_qtype_ops pci_ops
= {
662 .magic
= MAGIC_QTYPE_OPS
,
664 .alloc
= __videobuf_alloc
,
665 .iolock
= __videobuf_iolock
,
666 .sync
= __videobuf_sync
,
667 .mmap_free
= __videobuf_mmap_free
,
668 .mmap_mapper
= __videobuf_mmap_mapper
,
669 .video_copy_to_user
= __videobuf_copy_to_user
,
670 .copy_stream
= __videobuf_copy_stream
,
673 void *videobuf_pci_alloc (size_t size
)
675 struct videobuf_queue q
;
677 /* Required to make generic handler to call __videobuf_alloc */
682 return videobuf_alloc (&q
);
685 void videobuf_queue_pci_init(struct videobuf_queue
* q
,
686 struct videobuf_queue_ops
*ops
,
689 enum v4l2_buf_type type
,
690 enum v4l2_field field
,
694 videobuf_queue_core_init(q
, ops
, dev
, irqlock
, type
, field
, msize
,
698 /* --------------------------------------------------------------------- */
700 EXPORT_SYMBOL_GPL(videobuf_vmalloc_to_sg
);
702 EXPORT_SYMBOL_GPL(videobuf_to_dma
);
703 EXPORT_SYMBOL_GPL(videobuf_dma_init
);
704 EXPORT_SYMBOL_GPL(videobuf_dma_init_user
);
705 EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel
);
706 EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay
);
707 EXPORT_SYMBOL_GPL(videobuf_dma_map
);
708 EXPORT_SYMBOL_GPL(videobuf_dma_sync
);
709 EXPORT_SYMBOL_GPL(videobuf_dma_unmap
);
710 EXPORT_SYMBOL_GPL(videobuf_dma_free
);
712 EXPORT_SYMBOL_GPL(videobuf_pci_dma_map
);
713 EXPORT_SYMBOL_GPL(videobuf_pci_dma_unmap
);
714 EXPORT_SYMBOL_GPL(videobuf_pci_alloc
);
716 EXPORT_SYMBOL_GPL(videobuf_queue_pci_init
);