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/sched.h>
25 #include <linux/slab.h>
26 #include <linux/interrupt.h>
28 #include <linux/dma-mapping.h>
29 #include <linux/vmalloc.h>
30 #include <linux/pagemap.h>
31 #include <linux/scatterlist.h>
33 #include <asm/pgtable.h>
35 #include <media/videobuf-dma-sg.h>
37 #define MAGIC_DMABUF 0x19721112
38 #define MAGIC_SG_MEM 0x17890714
40 #define MAGIC_CHECK(is, should) \
41 if (unlikely((is) != (should))) { \
42 printk(KERN_ERR "magic mismatch: %x (expected %x)\n", \
48 module_param(debug, int, 0644);
50 MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers");
51 MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
52 MODULE_LICENSE("GPL");
54 #define dprintk(level, fmt, arg...) \
56 printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
58 /* --------------------------------------------------------------------- */
60 struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt, int nr_pages)
62 struct scatterlist *sglist;
66 sglist = vmalloc(nr_pages * sizeof(*sglist));
69 memset(sglist, 0, nr_pages * sizeof(*sglist));
70 sg_init_table(sglist, nr_pages);
71 for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
72 pg = vmalloc_to_page(virt);
75 BUG_ON(PageHighMem(pg));
76 sg_set_page(&sglist[i], pg, PAGE_SIZE, 0);
84 EXPORT_SYMBOL_GPL(videobuf_vmalloc_to_sg);
86 struct scatterlist *videobuf_pages_to_sg(struct page **pages, int nr_pages,
89 struct scatterlist *sglist;
94 sglist = vmalloc(nr_pages * sizeof(*sglist));
97 sg_init_table(sglist, nr_pages);
99 if (PageHighMem(pages[0]))
100 /* DMA to highmem pages might not work */
102 sg_set_page(&sglist[0], pages[0], PAGE_SIZE - offset, offset);
103 for (i = 1; i < nr_pages; i++) {
104 if (NULL == pages[i])
106 if (PageHighMem(pages[i]))
108 sg_set_page(&sglist[i], pages[i], PAGE_SIZE, 0);
113 dprintk(2, "sgl: oops - no page\n");
118 dprintk(2, "sgl: oops - highmem page\n");
123 /* --------------------------------------------------------------------- */
125 struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf)
127 struct videobuf_dma_sg_memory *mem = buf->priv;
130 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
134 EXPORT_SYMBOL_GPL(videobuf_to_dma);
136 void videobuf_dma_init(struct videobuf_dmabuf *dma)
138 memset(dma, 0, sizeof(*dma));
139 dma->magic = MAGIC_DMABUF;
141 EXPORT_SYMBOL_GPL(videobuf_dma_init);
143 static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
144 int direction, unsigned long data, unsigned long size)
146 unsigned long first, last;
149 dma->direction = direction;
150 switch (dma->direction) {
151 case DMA_FROM_DEVICE:
161 first = (data & PAGE_MASK) >> PAGE_SHIFT;
162 last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
163 dma->offset = data & ~PAGE_MASK;
164 dma->nr_pages = last-first+1;
165 dma->pages = kmalloc(dma->nr_pages * sizeof(struct page *), GFP_KERNEL);
166 if (NULL == dma->pages)
169 dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
170 data, size, dma->nr_pages);
172 err = get_user_pages(current, current->mm,
173 data & PAGE_MASK, dma->nr_pages,
174 rw == READ, 1, /* force */
177 if (err != dma->nr_pages) {
178 dma->nr_pages = (err >= 0) ? err : 0;
179 dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages);
180 return err < 0 ? err : -EINVAL;
185 int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
186 unsigned long data, unsigned long size)
190 down_read(¤t->mm->mmap_sem);
191 ret = videobuf_dma_init_user_locked(dma, direction, data, size);
192 up_read(¤t->mm->mmap_sem);
196 EXPORT_SYMBOL_GPL(videobuf_dma_init_user);
198 int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
201 dprintk(1, "init kernel [%d pages]\n", nr_pages);
203 dma->direction = direction;
204 dma->vmalloc = vmalloc_32(nr_pages << PAGE_SHIFT);
205 if (NULL == dma->vmalloc) {
206 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
210 dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
211 (unsigned long)dma->vmalloc,
212 nr_pages << PAGE_SHIFT);
214 memset(dma->vmalloc, 0, nr_pages << PAGE_SHIFT);
215 dma->nr_pages = nr_pages;
219 EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel);
221 int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
222 dma_addr_t addr, int nr_pages)
224 dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n",
225 nr_pages, (unsigned long)addr);
226 dma->direction = direction;
231 dma->bus_addr = addr;
232 dma->nr_pages = nr_pages;
236 EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay);
238 int videobuf_dma_map(struct videobuf_queue *q, struct videobuf_dmabuf *dma)
240 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
241 BUG_ON(0 == dma->nr_pages);
244 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
248 dma->sglist = videobuf_vmalloc_to_sg(dma->vmalloc,
252 dma->sglist = vmalloc(sizeof(*dma->sglist));
253 if (NULL != dma->sglist) {
255 sg_dma_address(&dma->sglist[0]) = dma->bus_addr
257 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
258 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
261 if (NULL == dma->sglist) {
262 dprintk(1, "scatterlist is NULL\n");
265 if (!dma->bus_addr) {
266 dma->sglen = dma_map_sg(q->dev, dma->sglist,
267 dma->nr_pages, dma->direction);
268 if (0 == dma->sglen) {
270 "%s: videobuf_map_sg failed\n", __func__);
280 EXPORT_SYMBOL_GPL(videobuf_dma_map);
282 int videobuf_dma_unmap(struct videobuf_queue *q, struct videobuf_dmabuf *dma)
284 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
289 dma_unmap_sg(q->dev, dma->sglist, dma->sglen, dma->direction);
297 EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
299 int videobuf_dma_free(struct videobuf_dmabuf *dma)
302 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
306 for (i = 0; i < dma->nr_pages; i++)
307 page_cache_release(dma->pages[i]);
317 dma->direction = DMA_NONE;
321 EXPORT_SYMBOL_GPL(videobuf_dma_free);
323 /* --------------------------------------------------------------------- */
325 int videobuf_sg_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
327 struct videobuf_queue q;
331 return videobuf_dma_map(&q, dma);
333 EXPORT_SYMBOL_GPL(videobuf_sg_dma_map);
335 int videobuf_sg_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
337 struct videobuf_queue q;
341 return videobuf_dma_unmap(&q, dma);
343 EXPORT_SYMBOL_GPL(videobuf_sg_dma_unmap);
345 /* --------------------------------------------------------------------- */
347 static void videobuf_vm_open(struct vm_area_struct *vma)
349 struct videobuf_mapping *map = vma->vm_private_data;
351 dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
352 map->count, vma->vm_start, vma->vm_end);
357 static void videobuf_vm_close(struct vm_area_struct *vma)
359 struct videobuf_mapping *map = vma->vm_private_data;
360 struct videobuf_queue *q = map->q;
361 struct videobuf_dma_sg_memory *mem;
364 dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
365 map->count, vma->vm_start, vma->vm_end);
368 if (0 == map->count) {
369 dprintk(1, "munmap %p q=%p\n", map, q);
370 mutex_lock(&q->vb_lock);
371 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
372 if (NULL == q->bufs[i])
374 mem = q->bufs[i]->priv;
378 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
380 if (q->bufs[i]->map != map)
382 q->bufs[i]->map = NULL;
383 q->bufs[i]->baddr = 0;
384 q->ops->buf_release(q, q->bufs[i]);
386 mutex_unlock(&q->vb_lock);
393 * Get a anonymous page for the mapping. Make sure we can DMA to that
394 * memory location with 32bit PCI devices (i.e. don't use highmem for
395 * now ...). Bounce buffers don't work very well for the data rates
398 static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
402 dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
403 (unsigned long)vmf->virtual_address,
404 vma->vm_start, vma->vm_end);
406 page = alloc_page(GFP_USER | __GFP_DMA32);
409 clear_user_highpage(page, (unsigned long)vmf->virtual_address);
415 static const struct vm_operations_struct videobuf_vm_ops = {
416 .open = videobuf_vm_open,
417 .close = videobuf_vm_close,
418 .fault = videobuf_vm_fault,
421 /* ---------------------------------------------------------------------
422 * SG handlers for the generic methods
425 /* Allocated area consists on 3 parts:
427 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
428 struct videobuf_dma_sg_memory
431 static struct videobuf_buffer *__videobuf_alloc(size_t size)
433 struct videobuf_dma_sg_memory *mem;
434 struct videobuf_buffer *vb;
436 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
440 mem = vb->priv = ((char *)vb) + size;
441 mem->magic = MAGIC_SG_MEM;
443 videobuf_dma_init(&mem->dma);
445 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
446 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
447 mem, (long)sizeof(*mem));
452 static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
454 struct videobuf_dma_sg_memory *mem = buf->priv;
457 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
459 return mem->dma.vmalloc;
462 static int __videobuf_iolock(struct videobuf_queue *q,
463 struct videobuf_buffer *vb,
464 struct v4l2_framebuffer *fbuf)
468 struct videobuf_dma_sg_memory *mem = vb->priv;
471 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
473 switch (vb->memory) {
474 case V4L2_MEMORY_MMAP:
475 case V4L2_MEMORY_USERPTR:
476 if (0 == vb->baddr) {
477 /* no userspace addr -- kernel bounce buffer */
478 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
479 err = videobuf_dma_init_kernel(&mem->dma,
484 } else if (vb->memory == V4L2_MEMORY_USERPTR) {
485 /* dma directly to userspace */
486 err = videobuf_dma_init_user(&mem->dma,
488 vb->baddr, vb->bsize);
492 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
493 buffers can only be called from videobuf_qbuf
494 we take current->mm->mmap_sem there, to prevent
495 locking inversion, so don't take it here */
497 err = videobuf_dma_init_user_locked(&mem->dma,
499 vb->baddr, vb->bsize);
504 case V4L2_MEMORY_OVERLAY:
507 /* FIXME: need sanity checks for vb->boff */
509 * Using a double cast to avoid compiler warnings when
510 * building for PAE. Compiler doesn't like direct casting
511 * of a 32 bit ptr to 64 bit integer.
513 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
514 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
515 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
523 err = videobuf_dma_map(q, &mem->dma);
530 static int __videobuf_sync(struct videobuf_queue *q,
531 struct videobuf_buffer *buf)
533 struct videobuf_dma_sg_memory *mem = buf->priv;
534 BUG_ON(!mem || !mem->dma.sglen);
536 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
537 MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF);
539 dma_sync_sg_for_cpu(q->dev, mem->dma.sglist,
540 mem->dma.sglen, mem->dma.direction);
545 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
546 struct videobuf_buffer *buf,
547 struct vm_area_struct *vma)
549 struct videobuf_dma_sg_memory *mem = buf->priv;
550 struct videobuf_mapping *map;
551 unsigned int first, last, size = 0, i;
556 /* This function maintains backwards compatibility with V4L1 and will
557 * map more than one buffer if the vma length is equal to the combined
558 * size of multiple buffers than it will map them together. See
559 * VIDIOCGMBUF in the v4l spec
561 * TODO: Allow drivers to specify if they support this mode
565 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
567 /* look for first buffer to map */
568 for (first = 0; first < VIDEO_MAX_FRAME; first++) {
569 if (buf == q->bufs[first]) {
570 size = PAGE_ALIGN(q->bufs[first]->bsize);
575 /* paranoia, should never happen since buf is always valid. */
577 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
578 (vma->vm_pgoff << PAGE_SHIFT));
583 #ifdef CONFIG_VIDEO_V4L1_COMPAT
584 if (size != (vma->vm_end - vma->vm_start)) {
585 /* look for last buffer to map */
586 for (last = first + 1; last < VIDEO_MAX_FRAME; last++) {
587 if (NULL == q->bufs[last])
589 if (V4L2_MEMORY_MMAP != q->bufs[last]->memory)
591 if (q->bufs[last]->map) {
595 size += PAGE_ALIGN(q->bufs[last]->bsize);
596 if (size == (vma->vm_end - vma->vm_start))
599 if (VIDEO_MAX_FRAME == last) {
600 dprintk(1, "mmap app bug: size invalid [size=0x%lx]\n",
601 (vma->vm_end - vma->vm_start));
607 /* create mapping + update buffer list */
609 map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
614 for (i = first; i <= last; i++) {
615 if (NULL == q->bufs[i])
617 q->bufs[i]->map = map;
618 q->bufs[i]->baddr = vma->vm_start + size;
619 size += PAGE_ALIGN(q->bufs[i]->bsize);
623 map->start = vma->vm_start;
624 map->end = vma->vm_end;
626 vma->vm_ops = &videobuf_vm_ops;
627 vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
628 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
629 vma->vm_private_data = map;
630 dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
631 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last);
638 static struct videobuf_qtype_ops sg_ops = {
639 .magic = MAGIC_QTYPE_OPS,
641 .alloc = __videobuf_alloc,
642 .iolock = __videobuf_iolock,
643 .sync = __videobuf_sync,
644 .mmap_mapper = __videobuf_mmap_mapper,
645 .vaddr = __videobuf_to_vaddr,
648 void *videobuf_sg_alloc(size_t size)
650 struct videobuf_queue q;
652 /* Required to make generic handler to call __videobuf_alloc */
657 return videobuf_alloc(&q);
659 EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
661 void videobuf_queue_sg_init(struct videobuf_queue *q,
662 const struct videobuf_queue_ops *ops,
665 enum v4l2_buf_type type,
666 enum v4l2_field field,
670 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
673 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);