2 * helper functions for SG 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/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 = 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 videobuf_dma_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 DMA_FROM_DEVICE:
154 first = (data & PAGE_MASK) >> PAGE_SHIFT;
155 last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
156 dma->offset = data & ~PAGE_MASK;
157 dma->nr_pages = last-first+1;
158 dma->pages = kmalloc(dma->nr_pages * sizeof(struct page*),
160 if (NULL == dma->pages)
162 dprintk(1,"init user [0x%lx+0x%lx => %d pages]\n",
163 data,size,dma->nr_pages);
165 dma->varea = (void *) data;
168 err = get_user_pages(current,current->mm,
169 data & PAGE_MASK, dma->nr_pages,
170 rw == READ, 1, /* force */
173 if (err != dma->nr_pages) {
174 dma->nr_pages = (err >= 0) ? err : 0;
175 dprintk(1,"get_user_pages: err=%d [%d]\n",err,dma->nr_pages);
176 return err < 0 ? err : -EINVAL;
181 int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
182 unsigned long data, unsigned long size)
185 down_read(¤t->mm->mmap_sem);
186 ret = videobuf_dma_init_user_locked(dma, direction, data, size);
187 up_read(¤t->mm->mmap_sem);
192 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
195 dprintk(1,"init kernel [%d pages]\n",nr_pages);
196 dma->direction = direction;
197 dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
198 if (NULL == dma->vmalloc) {
199 dprintk(1,"vmalloc_32(%d pages) failed\n",nr_pages);
202 dprintk(1,"vmalloc is at addr 0x%08lx, size=%d\n",
203 (unsigned long)dma->vmalloc,
204 nr_pages << PAGE_SHIFT);
205 memset(dma->vmalloc,0,nr_pages << PAGE_SHIFT);
206 dma->nr_pages = nr_pages;
210 int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
211 dma_addr_t addr, int nr_pages)
213 dprintk(1,"init overlay [%d pages @ bus 0x%lx]\n",
214 nr_pages,(unsigned long)addr);
215 dma->direction = direction;
219 dma->bus_addr = addr;
220 dma->nr_pages = nr_pages;
224 int videobuf_dma_map(struct videobuf_queue* q, struct videobuf_dmabuf *dma)
226 MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
227 BUG_ON(0 == dma->nr_pages);
230 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
234 dma->sglist = videobuf_vmalloc_to_sg
235 (dma->vmalloc,dma->nr_pages);
238 dma->sglist = kmalloc(sizeof(struct scatterlist), GFP_KERNEL);
239 if (NULL != dma->sglist) {
241 sg_dma_address(&dma->sglist[0]) = dma->bus_addr & PAGE_MASK;
242 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
243 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
246 if (NULL == dma->sglist) {
247 dprintk(1,"scatterlist is NULL\n");
250 if (!dma->bus_addr) {
251 dma->sglen = dma_map_sg(q->dev, dma->sglist,
252 dma->nr_pages, dma->direction);
253 if (0 == dma->sglen) {
255 "%s: videobuf_map_sg failed\n",__FUNCTION__);
265 int videobuf_dma_sync(struct videobuf_queue *q, struct videobuf_dmabuf *dma)
267 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
270 dma_sync_sg_for_cpu(q->dev, dma->sglist, dma->nr_pages, dma->direction);
274 int videobuf_dma_unmap(struct videobuf_queue* q,struct videobuf_dmabuf *dma)
276 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
280 dma_unmap_sg(q->dev, dma->sglist, dma->nr_pages, dma->direction);
288 int videobuf_dma_free(struct videobuf_dmabuf *dma)
290 MAGIC_CHECK(dma->magic,MAGIC_DMABUF);
295 for (i=0; i < dma->nr_pages; i++)
296 page_cache_release(dma->pages[i]);
308 dma->direction = DMA_NONE;
312 /* --------------------------------------------------------------------- */
314 int videobuf_sg_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
316 struct videobuf_queue q;
320 return videobuf_dma_map(&q, dma);
323 int videobuf_sg_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
325 struct videobuf_queue q;
329 return videobuf_dma_unmap(&q, dma);
332 /* --------------------------------------------------------------------- */
335 videobuf_vm_open(struct vm_area_struct *vma)
337 struct videobuf_mapping *map = vma->vm_private_data;
339 dprintk(2,"vm_open %p [count=%d,vma=%08lx-%08lx]\n",map,
340 map->count,vma->vm_start,vma->vm_end);
345 videobuf_vm_close(struct vm_area_struct *vma)
347 struct videobuf_mapping *map = vma->vm_private_data;
348 struct videobuf_queue *q = map->q;
349 struct videobuf_dma_sg_memory *mem;
352 dprintk(2,"vm_close %p [count=%d,vma=%08lx-%08lx]\n",map,
353 map->count,vma->vm_start,vma->vm_end);
356 if (0 == map->count) {
357 dprintk(1,"munmap %p q=%p\n",map,q);
358 mutex_lock(&q->vb_lock);
359 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
360 if (NULL == q->bufs[i])
362 mem=q->bufs[i]->priv;
367 MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
369 if (q->bufs[i]->map != map)
371 q->bufs[i]->map = NULL;
372 q->bufs[i]->baddr = 0;
373 q->ops->buf_release(q,q->bufs[i]);
375 mutex_unlock(&q->vb_lock);
382 * Get a anonymous page for the mapping. Make sure we can DMA to that
383 * memory location with 32bit PCI devices (i.e. don't use highmem for
384 * now ...). Bounce buffers don't work very well for the data rates
388 videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
392 dprintk(3,"fault: fault @ %08lx [vma %08lx-%08lx]\n",
393 (unsigned long)vmf->virtual_address,vma->vm_start,vma->vm_end);
394 page = alloc_page(GFP_USER | __GFP_DMA32);
397 clear_user_page(page_address(page), (unsigned long)vmf->virtual_address,
403 static struct vm_operations_struct videobuf_vm_ops =
405 .open = videobuf_vm_open,
406 .close = videobuf_vm_close,
407 .fault = videobuf_vm_fault,
410 /* ---------------------------------------------------------------------
411 * SG handlers for the generic methods
414 /* Allocated area consists on 3 parts:
416 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
417 struct videobuf_dma_sg_memory
420 static void *__videobuf_alloc(size_t size)
422 struct videobuf_dma_sg_memory *mem;
423 struct videobuf_buffer *vb;
425 vb = kzalloc(size+sizeof(*mem),GFP_KERNEL);
427 mem = vb->priv = ((char *)vb)+size;
428 mem->magic=MAGIC_SG_MEM;
430 videobuf_dma_init(&mem->dma);
432 dprintk(1,"%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
433 __FUNCTION__,vb,(long)sizeof(*vb),(long)size-sizeof(*vb),
434 mem,(long)sizeof(*mem));
439 static int __videobuf_iolock (struct videobuf_queue* q,
440 struct videobuf_buffer *vb,
441 struct v4l2_framebuffer *fbuf)
445 struct videobuf_dma_sg_memory *mem = vb->priv;
448 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
450 switch (vb->memory) {
451 case V4L2_MEMORY_MMAP:
452 case V4L2_MEMORY_USERPTR:
453 if (0 == vb->baddr) {
454 /* no userspace addr -- kernel bounce buffer */
455 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
456 err = videobuf_dma_init_kernel( &mem->dma,
461 } else if (vb->memory == V4L2_MEMORY_USERPTR) {
462 /* dma directly to userspace */
463 err = videobuf_dma_init_user( &mem->dma,
465 vb->baddr,vb->bsize );
469 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
470 buffers can only be called from videobuf_qbuf
471 we take current->mm->mmap_sem there, to prevent
472 locking inversion, so don't take it here */
474 err = videobuf_dma_init_user_locked(&mem->dma,
476 vb->baddr, vb->bsize);
481 case V4L2_MEMORY_OVERLAY:
484 /* FIXME: need sanity checks for vb->boff */
486 * Using a double cast to avoid compiler warnings when
487 * building for PAE. Compiler doesn't like direct casting
488 * of a 32 bit ptr to 64 bit integer.
490 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
491 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
492 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
500 err = videobuf_dma_map(q, &mem->dma);
507 static int __videobuf_sync(struct videobuf_queue *q,
508 struct videobuf_buffer *buf)
510 struct videobuf_dma_sg_memory *mem = buf->priv;
512 MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
514 return videobuf_dma_sync(q,&mem->dma);
517 static int __videobuf_mmap_free(struct videobuf_queue *q)
521 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
531 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
532 struct vm_area_struct *vma)
534 struct videobuf_dma_sg_memory *mem;
535 struct videobuf_mapping *map;
536 unsigned int first,last,size,i;
540 if (!(vma->vm_flags & VM_WRITE)) {
541 dprintk(1,"mmap app bug: PROT_WRITE please\n");
544 if (!(vma->vm_flags & VM_SHARED)) {
545 dprintk(1,"mmap app bug: MAP_SHARED please\n");
549 /* This function maintains backwards compatibility with V4L1 and will
550 * map more than one buffer if the vma length is equal to the combined
551 * size of multiple buffers than it will map them together. See
552 * VIDIOCGMBUF in the v4l spec
554 * TODO: Allow drivers to specify if they support this mode
557 /* look for first buffer to map */
558 for (first = 0; first < VIDEO_MAX_FRAME; first++) {
559 if (NULL == q->bufs[first])
561 mem=q->bufs[first]->priv;
563 MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
565 if (V4L2_MEMORY_MMAP != q->bufs[first]->memory)
567 if (q->bufs[first]->boff == (vma->vm_pgoff << PAGE_SHIFT))
570 if (VIDEO_MAX_FRAME == first) {
571 dprintk(1,"mmap app bug: offset invalid [offset=0x%lx]\n",
572 (vma->vm_pgoff << PAGE_SHIFT));
576 /* look for last buffer to map */
577 for (size = 0, last = first; last < VIDEO_MAX_FRAME; last++) {
578 if (NULL == q->bufs[last])
580 if (V4L2_MEMORY_MMAP != q->bufs[last]->memory)
582 if (q->bufs[last]->map) {
586 size += q->bufs[last]->bsize;
587 if (size == (vma->vm_end - vma->vm_start))
590 if (VIDEO_MAX_FRAME == last) {
591 dprintk(1,"mmap app bug: size invalid [size=0x%lx]\n",
592 (vma->vm_end - vma->vm_start));
596 /* create mapping + update buffer list */
598 map = kmalloc(sizeof(struct videobuf_mapping),GFP_KERNEL);
603 for (i = first; i <= last; i++) {
604 if (NULL == q->bufs[i])
606 q->bufs[i]->map = map;
607 q->bufs[i]->baddr = vma->vm_start + size;
608 size += q->bufs[i]->bsize;
612 map->start = vma->vm_start;
613 map->end = vma->vm_end;
615 vma->vm_ops = &videobuf_vm_ops;
616 vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
617 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
618 vma->vm_private_data = map;
619 dprintk(1,"mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
620 map,q,vma->vm_start,vma->vm_end,vma->vm_pgoff,first,last);
627 static int __videobuf_copy_to_user ( struct videobuf_queue *q,
628 char __user *data, size_t count,
631 struct videobuf_dma_sg_memory *mem = q->read_buf->priv;
633 MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
635 /* copy to userspace */
636 if (count > q->read_buf->size - q->read_off)
637 count = q->read_buf->size - q->read_off;
639 if (copy_to_user(data, mem->dma.vmalloc+q->read_off, count))
645 static int __videobuf_copy_stream ( struct videobuf_queue *q,
646 char __user *data, size_t count, size_t pos,
647 int vbihack, int nonblocking )
650 struct videobuf_dma_sg_memory *mem = q->read_buf->priv;
652 MAGIC_CHECK(mem->magic,MAGIC_SG_MEM);
655 /* dirty, undocumented hack -- pass the frame counter
656 * within the last four bytes of each vbi data block.
657 * We need that one to maintain backward compatibility
658 * to all vbi decoding software out there ... */
659 fc = (unsigned int*)mem->dma.vmalloc;
660 fc += (q->read_buf->size>>2) -1;
661 *fc = q->read_buf->field_count >> 1;
662 dprintk(1,"vbihack: %d\n",*fc);
665 /* copy stuff using the common method */
666 count = __videobuf_copy_to_user (q,data,count,nonblocking);
668 if ( (count==-EFAULT) && (0 == pos) )
674 static struct videobuf_qtype_ops sg_ops = {
675 .magic = MAGIC_QTYPE_OPS,
677 .alloc = __videobuf_alloc,
678 .iolock = __videobuf_iolock,
679 .sync = __videobuf_sync,
680 .mmap_free = __videobuf_mmap_free,
681 .mmap_mapper = __videobuf_mmap_mapper,
682 .video_copy_to_user = __videobuf_copy_to_user,
683 .copy_stream = __videobuf_copy_stream,
686 void *videobuf_sg_alloc(size_t size)
688 struct videobuf_queue q;
690 /* Required to make generic handler to call __videobuf_alloc */
695 return videobuf_alloc(&q);
698 void videobuf_queue_sg_init(struct videobuf_queue* q,
699 struct videobuf_queue_ops *ops,
702 enum v4l2_buf_type type,
703 enum v4l2_field field,
707 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
711 /* --------------------------------------------------------------------- */
713 EXPORT_SYMBOL_GPL(videobuf_vmalloc_to_sg);
715 EXPORT_SYMBOL_GPL(videobuf_to_dma);
716 EXPORT_SYMBOL_GPL(videobuf_dma_init);
717 EXPORT_SYMBOL_GPL(videobuf_dma_init_user);
718 EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel);
719 EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay);
720 EXPORT_SYMBOL_GPL(videobuf_dma_map);
721 EXPORT_SYMBOL_GPL(videobuf_dma_sync);
722 EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
723 EXPORT_SYMBOL_GPL(videobuf_dma_free);
725 EXPORT_SYMBOL_GPL(videobuf_sg_dma_map);
726 EXPORT_SYMBOL_GPL(videobuf_sg_dma_unmap);
727 EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
729 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);