2 * helper functions for SG DMA video4linux capture buffers
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.
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/dma-mapping.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 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
= kmalloc(nr_pages
* sizeof(*sglist
), GFP_KERNEL
);
90 sg_init_table(sglist
, nr_pages
);
92 if (PageHighMem(pages
[0]))
93 /* DMA to highmem pages might not work */
95 sg_set_page(&sglist
[0], pages
[0], PAGE_SIZE
- offset
, offset
);
96 for (i
= 1; i
< nr_pages
; i
++) {
99 if (PageHighMem(pages
[i
]))
101 sg_set_page(&sglist
[i
], pages
[i
], PAGE_SIZE
, 0);
106 dprintk(2,"sgl: oops - no page\n");
111 dprintk(2,"sgl: oops - highmem page\n");
116 /* --------------------------------------------------------------------- */
118 struct videobuf_dmabuf
*videobuf_to_dma (struct videobuf_buffer
*buf
)
120 struct videobuf_dma_sg_memory
*mem
= buf
->priv
;
123 MAGIC_CHECK(mem
->magic
, MAGIC_SG_MEM
);
128 void videobuf_dma_init(struct videobuf_dmabuf
*dma
)
130 memset(dma
,0,sizeof(*dma
));
131 dma
->magic
= MAGIC_DMABUF
;
134 static int videobuf_dma_init_user_locked(struct videobuf_dmabuf
*dma
,
135 int direction
, unsigned long data
, unsigned long size
)
137 unsigned long first
,last
;
140 dma
->direction
= direction
;
141 switch (dma
->direction
) {
142 case DMA_FROM_DEVICE
:
152 first
= (data
& PAGE_MASK
) >> PAGE_SHIFT
;
153 last
= ((data
+size
-1) & PAGE_MASK
) >> PAGE_SHIFT
;
154 dma
->offset
= data
& ~PAGE_MASK
;
155 dma
->nr_pages
= last
-first
+1;
156 dma
->pages
= kmalloc(dma
->nr_pages
* sizeof(struct page
*),
158 if (NULL
== dma
->pages
)
160 dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
161 data
,size
,dma
->nr_pages
);
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
)
221 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
222 BUG_ON(0 == dma
->nr_pages
);
225 dma
->sglist
= videobuf_pages_to_sg(dma
->pages
, dma
->nr_pages
,
229 dma
->sglist
= videobuf_vmalloc_to_sg
230 (dma
->vmalloc
,dma
->nr_pages
);
233 dma
->sglist
= kmalloc(sizeof(struct scatterlist
), GFP_KERNEL
);
234 if (NULL
!= dma
->sglist
) {
236 sg_dma_address(&dma
->sglist
[0]) = dma
->bus_addr
& PAGE_MASK
;
237 dma
->sglist
[0].offset
= dma
->bus_addr
& ~PAGE_MASK
;
238 sg_dma_len(&dma
->sglist
[0]) = dma
->nr_pages
* PAGE_SIZE
;
241 if (NULL
== dma
->sglist
) {
242 dprintk(1,"scatterlist is NULL\n");
245 if (!dma
->bus_addr
) {
246 dma
->sglen
= dma_map_sg(q
->dev
, dma
->sglist
,
247 dma
->nr_pages
, dma
->direction
);
248 if (0 == dma
->sglen
) {
250 "%s: videobuf_map_sg failed\n",__func__
);
260 int videobuf_dma_sync(struct videobuf_queue
*q
, struct videobuf_dmabuf
*dma
)
262 MAGIC_CHECK(dma
->magic
, MAGIC_DMABUF
);
265 dma_sync_sg_for_cpu(q
->dev
, dma
->sglist
, dma
->nr_pages
, dma
->direction
);
269 int videobuf_dma_unmap(struct videobuf_queue
* q
,struct videobuf_dmabuf
*dma
)
271 MAGIC_CHECK(dma
->magic
, MAGIC_DMABUF
);
275 dma_unmap_sg(q
->dev
, dma
->sglist
, dma
->nr_pages
, dma
->direction
);
283 int videobuf_dma_free(struct videobuf_dmabuf
*dma
)
285 MAGIC_CHECK(dma
->magic
,MAGIC_DMABUF
);
290 for (i
=0; i
< dma
->nr_pages
; i
++)
291 page_cache_release(dma
->pages
[i
]);
302 dma
->direction
= DMA_NONE
;
306 /* --------------------------------------------------------------------- */
308 int videobuf_sg_dma_map(struct device
*dev
, struct videobuf_dmabuf
*dma
)
310 struct videobuf_queue q
;
314 return videobuf_dma_map(&q
, dma
);
317 int videobuf_sg_dma_unmap(struct device
*dev
, struct videobuf_dmabuf
*dma
)
319 struct videobuf_queue q
;
323 return videobuf_dma_unmap(&q
, dma
);
326 /* --------------------------------------------------------------------- */
329 videobuf_vm_open(struct vm_area_struct
*vma
)
331 struct videobuf_mapping
*map
= vma
->vm_private_data
;
333 dprintk(2,"vm_open %p [count=%d,vma=%08lx-%08lx]\n",map
,
334 map
->count
,vma
->vm_start
,vma
->vm_end
);
339 videobuf_vm_close(struct vm_area_struct
*vma
)
341 struct videobuf_mapping
*map
= vma
->vm_private_data
;
342 struct videobuf_queue
*q
= map
->q
;
343 struct videobuf_dma_sg_memory
*mem
;
346 dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map
,
347 map
->count
,vma
->vm_start
,vma
->vm_end
);
350 if (0 == map
->count
) {
351 dprintk(1,"munmap %p q=%p\n",map
,q
);
352 mutex_lock(&q
->vb_lock
);
353 for (i
= 0; i
< VIDEO_MAX_FRAME
; i
++) {
354 if (NULL
== q
->bufs
[i
])
356 mem
=q
->bufs
[i
]->priv
;
361 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
363 if (q
->bufs
[i
]->map
!= map
)
365 q
->bufs
[i
]->map
= NULL
;
366 q
->bufs
[i
]->baddr
= 0;
367 q
->ops
->buf_release(q
,q
->bufs
[i
]);
369 mutex_unlock(&q
->vb_lock
);
376 * Get a anonymous page for the mapping. Make sure we can DMA to that
377 * memory location with 32bit PCI devices (i.e. don't use highmem for
378 * now ...). Bounce buffers don't work very well for the data rates
382 videobuf_vm_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
386 dprintk(3,"fault: fault @ %08lx [vma %08lx-%08lx]\n",
387 (unsigned long)vmf
->virtual_address
,vma
->vm_start
,vma
->vm_end
);
388 page
= alloc_page(GFP_USER
| __GFP_DMA32
);
391 clear_user_highpage(page
, (unsigned long)vmf
->virtual_address
);
396 static struct vm_operations_struct videobuf_vm_ops
=
398 .open
= videobuf_vm_open
,
399 .close
= videobuf_vm_close
,
400 .fault
= videobuf_vm_fault
,
403 /* ---------------------------------------------------------------------
404 * SG handlers for the generic methods
407 /* Allocated area consists on 3 parts:
409 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
410 struct videobuf_dma_sg_memory
413 static void *__videobuf_alloc(size_t size
)
415 struct videobuf_dma_sg_memory
*mem
;
416 struct videobuf_buffer
*vb
;
418 vb
= kzalloc(size
+sizeof(*mem
),GFP_KERNEL
);
420 mem
= vb
->priv
= ((char *)vb
)+size
;
421 mem
->magic
=MAGIC_SG_MEM
;
423 videobuf_dma_init(&mem
->dma
);
425 dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
426 __func__
,vb
,(long)sizeof(*vb
),(long)size
-sizeof(*vb
),
427 mem
,(long)sizeof(*mem
));
432 static void *__videobuf_to_vmalloc (struct videobuf_buffer
*buf
)
434 struct videobuf_dma_sg_memory
*mem
= buf
->priv
;
437 MAGIC_CHECK(mem
->magic
, MAGIC_SG_MEM
);
439 return mem
->dma
.vmalloc
;
442 static int __videobuf_iolock (struct videobuf_queue
* q
,
443 struct videobuf_buffer
*vb
,
444 struct v4l2_framebuffer
*fbuf
)
448 struct videobuf_dma_sg_memory
*mem
= vb
->priv
;
451 MAGIC_CHECK(mem
->magic
, MAGIC_SG_MEM
);
453 switch (vb
->memory
) {
454 case V4L2_MEMORY_MMAP
:
455 case V4L2_MEMORY_USERPTR
:
456 if (0 == vb
->baddr
) {
457 /* no userspace addr -- kernel bounce buffer */
458 pages
= PAGE_ALIGN(vb
->size
) >> PAGE_SHIFT
;
459 err
= videobuf_dma_init_kernel( &mem
->dma
,
464 } else if (vb
->memory
== V4L2_MEMORY_USERPTR
) {
465 /* dma directly to userspace */
466 err
= videobuf_dma_init_user( &mem
->dma
,
468 vb
->baddr
,vb
->bsize
);
472 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
473 buffers can only be called from videobuf_qbuf
474 we take current->mm->mmap_sem there, to prevent
475 locking inversion, so don't take it here */
477 err
= videobuf_dma_init_user_locked(&mem
->dma
,
479 vb
->baddr
, vb
->bsize
);
484 case V4L2_MEMORY_OVERLAY
:
487 /* FIXME: need sanity checks for vb->boff */
489 * Using a double cast to avoid compiler warnings when
490 * building for PAE. Compiler doesn't like direct casting
491 * of a 32 bit ptr to 64 bit integer.
493 bus
= (dma_addr_t
)(unsigned long)fbuf
->base
+ vb
->boff
;
494 pages
= PAGE_ALIGN(vb
->size
) >> PAGE_SHIFT
;
495 err
= videobuf_dma_init_overlay(&mem
->dma
, DMA_FROM_DEVICE
,
503 err
= videobuf_dma_map(q
, &mem
->dma
);
510 static int __videobuf_sync(struct videobuf_queue
*q
,
511 struct videobuf_buffer
*buf
)
513 struct videobuf_dma_sg_memory
*mem
= buf
->priv
;
515 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
517 return videobuf_dma_sync(q
,&mem
->dma
);
520 static int __videobuf_mmap_free(struct videobuf_queue
*q
)
524 for (i
= 0; i
< VIDEO_MAX_FRAME
; i
++) {
534 static int __videobuf_mmap_mapper(struct videobuf_queue
*q
,
535 struct vm_area_struct
*vma
)
537 struct videobuf_dma_sg_memory
*mem
;
538 struct videobuf_mapping
*map
;
539 unsigned int first
,last
,size
,i
;
543 if (!(vma
->vm_flags
& VM_WRITE
)) {
544 dprintk(1,"mmap app bug: PROT_WRITE please\n");
547 if (!(vma
->vm_flags
& VM_SHARED
)) {
548 dprintk(1,"mmap app bug: MAP_SHARED please\n");
552 /* This function maintains backwards compatibility with V4L1 and will
553 * map more than one buffer if the vma length is equal to the combined
554 * size of multiple buffers than it will map them together. See
555 * VIDIOCGMBUF in the v4l spec
557 * TODO: Allow drivers to specify if they support this mode
560 /* look for first buffer to map */
561 for (first
= 0; first
< VIDEO_MAX_FRAME
; first
++) {
562 if (NULL
== q
->bufs
[first
])
564 mem
=q
->bufs
[first
]->priv
;
566 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
568 if (V4L2_MEMORY_MMAP
!= q
->bufs
[first
]->memory
)
570 if (q
->bufs
[first
]->boff
== (vma
->vm_pgoff
<< PAGE_SHIFT
))
573 if (VIDEO_MAX_FRAME
== first
) {
574 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
575 (vma
->vm_pgoff
<< PAGE_SHIFT
));
579 /* look for last buffer to map */
580 for (size
= 0, last
= first
; last
< VIDEO_MAX_FRAME
; last
++) {
581 if (NULL
== q
->bufs
[last
])
583 if (V4L2_MEMORY_MMAP
!= q
->bufs
[last
]->memory
)
585 if (q
->bufs
[last
]->map
) {
589 size
+= q
->bufs
[last
]->bsize
;
590 if (size
== (vma
->vm_end
- vma
->vm_start
))
593 if (VIDEO_MAX_FRAME
== last
) {
594 dprintk(1,"mmap app bug: size invalid [size=0x%lx]\n",
595 (vma
->vm_end
- vma
->vm_start
));
599 /* create mapping + update buffer list */
601 map
= kmalloc(sizeof(struct videobuf_mapping
),GFP_KERNEL
);
606 for (i
= first
; i
<= last
; i
++) {
607 if (NULL
== q
->bufs
[i
])
609 q
->bufs
[i
]->map
= map
;
610 q
->bufs
[i
]->baddr
= vma
->vm_start
+ size
;
611 size
+= q
->bufs
[i
]->bsize
;
615 map
->start
= vma
->vm_start
;
616 map
->end
= vma
->vm_end
;
618 vma
->vm_ops
= &videobuf_vm_ops
;
619 vma
->vm_flags
|= VM_DONTEXPAND
| VM_RESERVED
;
620 vma
->vm_flags
&= ~VM_IO
; /* using shared anonymous pages */
621 vma
->vm_private_data
= map
;
622 dprintk(1,"mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
623 map
,q
,vma
->vm_start
,vma
->vm_end
,vma
->vm_pgoff
,first
,last
);
630 static int __videobuf_copy_to_user ( struct videobuf_queue
*q
,
631 char __user
*data
, size_t count
,
634 struct videobuf_dma_sg_memory
*mem
= q
->read_buf
->priv
;
636 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
638 /* copy to userspace */
639 if (count
> q
->read_buf
->size
- q
->read_off
)
640 count
= q
->read_buf
->size
- q
->read_off
;
642 if (copy_to_user(data
, mem
->dma
.vmalloc
+q
->read_off
, count
))
648 static int __videobuf_copy_stream ( struct videobuf_queue
*q
,
649 char __user
*data
, size_t count
, size_t pos
,
650 int vbihack
, int nonblocking
)
653 struct videobuf_dma_sg_memory
*mem
= q
->read_buf
->priv
;
655 MAGIC_CHECK(mem
->magic
,MAGIC_SG_MEM
);
658 /* dirty, undocumented hack -- pass the frame counter
659 * within the last four bytes of each vbi data block.
660 * We need that one to maintain backward compatibility
661 * to all vbi decoding software out there ... */
662 fc
= (unsigned int*)mem
->dma
.vmalloc
;
663 fc
+= (q
->read_buf
->size
>>2) -1;
664 *fc
= q
->read_buf
->field_count
>> 1;
665 dprintk(1,"vbihack: %d\n",*fc
);
668 /* copy stuff using the common method */
669 count
= __videobuf_copy_to_user (q
,data
,count
,nonblocking
);
671 if ( (count
==-EFAULT
) && (0 == pos
) )
677 static struct videobuf_qtype_ops sg_ops
= {
678 .magic
= MAGIC_QTYPE_OPS
,
680 .alloc
= __videobuf_alloc
,
681 .iolock
= __videobuf_iolock
,
682 .sync
= __videobuf_sync
,
683 .mmap_free
= __videobuf_mmap_free
,
684 .mmap_mapper
= __videobuf_mmap_mapper
,
685 .video_copy_to_user
= __videobuf_copy_to_user
,
686 .copy_stream
= __videobuf_copy_stream
,
687 .vmalloc
= __videobuf_to_vmalloc
,
690 void *videobuf_sg_alloc(size_t size
)
692 struct videobuf_queue q
;
694 /* Required to make generic handler to call __videobuf_alloc */
699 return videobuf_alloc(&q
);
702 void videobuf_queue_sg_init(struct videobuf_queue
* q
,
703 struct videobuf_queue_ops
*ops
,
706 enum v4l2_buf_type type
,
707 enum v4l2_field field
,
711 videobuf_queue_core_init(q
, ops
, dev
, irqlock
, type
, field
, msize
,
715 /* --------------------------------------------------------------------- */
717 EXPORT_SYMBOL_GPL(videobuf_vmalloc_to_sg
);
719 EXPORT_SYMBOL_GPL(videobuf_to_dma
);
720 EXPORT_SYMBOL_GPL(videobuf_dma_init
);
721 EXPORT_SYMBOL_GPL(videobuf_dma_init_user
);
722 EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel
);
723 EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay
);
724 EXPORT_SYMBOL_GPL(videobuf_dma_map
);
725 EXPORT_SYMBOL_GPL(videobuf_dma_sync
);
726 EXPORT_SYMBOL_GPL(videobuf_dma_unmap
);
727 EXPORT_SYMBOL_GPL(videobuf_dma_free
);
729 EXPORT_SYMBOL_GPL(videobuf_sg_dma_map
);
730 EXPORT_SYMBOL_GPL(videobuf_sg_dma_unmap
);
731 EXPORT_SYMBOL_GPL(videobuf_sg_alloc
);
733 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init
);