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 /* --------------------------------------------------------------------- */
61 * Return a scatterlist for some page-aligned vmalloc()'ed memory
62 * block (NULL on errors). Memory for the scatterlist is allocated
63 * using kmalloc. The caller must free the memory.
65 static struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt,
68 struct scatterlist *sglist;
72 sglist = vzalloc(nr_pages * sizeof(*sglist));
75 sg_init_table(sglist, nr_pages);
76 for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
77 pg = vmalloc_to_page(virt);
80 BUG_ON(PageHighMem(pg));
81 sg_set_page(&sglist[i], pg, PAGE_SIZE, 0);
91 * Return a scatterlist for a an array of userpages (NULL on errors).
92 * Memory for the scatterlist is allocated using kmalloc. The caller
93 * must free the memory.
95 static struct scatterlist *videobuf_pages_to_sg(struct page **pages,
96 int nr_pages, int offset, size_t size)
98 struct scatterlist *sglist;
101 if (NULL == pages[0])
103 sglist = vmalloc(nr_pages * sizeof(*sglist));
106 sg_init_table(sglist, nr_pages);
108 if (PageHighMem(pages[0]))
109 /* DMA to highmem pages might not work */
111 sg_set_page(&sglist[0], pages[0],
112 min_t(size_t, PAGE_SIZE - offset, size), offset);
113 size -= min_t(size_t, PAGE_SIZE - offset, size);
114 for (i = 1; i < nr_pages; i++) {
115 if (NULL == pages[i])
117 if (PageHighMem(pages[i]))
119 sg_set_page(&sglist[i], pages[i], min_t(size_t, PAGE_SIZE, size), 0);
120 size -= min_t(size_t, PAGE_SIZE, size);
125 dprintk(2, "sgl: oops - no page\n");
130 dprintk(2, "sgl: oops - highmem page\n");
135 /* --------------------------------------------------------------------- */
137 struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf)
139 struct videobuf_dma_sg_memory *mem = buf->priv;
142 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
146 EXPORT_SYMBOL_GPL(videobuf_to_dma);
148 static void videobuf_dma_init(struct videobuf_dmabuf *dma)
150 memset(dma, 0, sizeof(*dma));
151 dma->magic = MAGIC_DMABUF;
154 static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
155 int direction, unsigned long data, unsigned long size)
157 unsigned long first, last;
160 dma->direction = direction;
161 switch (dma->direction) {
162 case DMA_FROM_DEVICE:
172 first = (data & PAGE_MASK) >> PAGE_SHIFT;
173 last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
174 dma->offset = data & ~PAGE_MASK;
176 dma->nr_pages = last-first+1;
177 dma->pages = kmalloc(dma->nr_pages * sizeof(struct page *), GFP_KERNEL);
178 if (NULL == dma->pages)
181 dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
182 data, size, dma->nr_pages);
184 err = get_user_pages(current, current->mm,
185 data & PAGE_MASK, dma->nr_pages,
186 rw == READ, 1, /* force */
189 if (err != dma->nr_pages) {
190 dma->nr_pages = (err >= 0) ? err : 0;
191 dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages);
192 return err < 0 ? err : -EINVAL;
197 static int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
198 unsigned long data, unsigned long size)
202 down_read(¤t->mm->mmap_sem);
203 ret = videobuf_dma_init_user_locked(dma, direction, data, size);
204 up_read(¤t->mm->mmap_sem);
209 static int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
214 dprintk(1, "init kernel [%d pages]\n", nr_pages);
216 dma->direction = direction;
217 dma->vaddr_pages = kcalloc(nr_pages, sizeof(*dma->vaddr_pages),
219 if (!dma->vaddr_pages)
222 dma->dma_addr = kcalloc(nr_pages, sizeof(*dma->dma_addr), GFP_KERNEL);
223 if (!dma->dma_addr) {
224 kfree(dma->vaddr_pages);
227 for (i = 0; i < nr_pages; i++) {
230 addr = dma_alloc_coherent(dma->dev, PAGE_SIZE,
231 &(dma->dma_addr[i]), GFP_KERNEL);
235 dma->vaddr_pages[i] = virt_to_page(addr);
237 dma->vaddr = vmap(dma->vaddr_pages, nr_pages, VM_MAP | VM_IOREMAP,
239 if (NULL == dma->vaddr) {
240 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
244 dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
245 (unsigned long)dma->vaddr,
246 nr_pages << PAGE_SHIFT);
248 memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT);
249 dma->nr_pages = nr_pages;
257 addr = page_address(dma->vaddr_pages[i]);
258 dma_free_coherent(dma->dev, PAGE_SIZE, addr, dma->dma_addr[i]);
260 kfree(dma->dma_addr);
261 dma->dma_addr = NULL;
262 kfree(dma->vaddr_pages);
263 dma->vaddr_pages = NULL;
269 static int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
270 dma_addr_t addr, int nr_pages)
272 dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n",
273 nr_pages, (unsigned long)addr);
274 dma->direction = direction;
279 dma->bus_addr = addr;
280 dma->nr_pages = nr_pages;
285 static int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
287 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
288 BUG_ON(0 == dma->nr_pages);
291 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
292 dma->offset, dma->size);
295 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr,
299 dma->sglist = vmalloc(sizeof(*dma->sglist));
300 if (NULL != dma->sglist) {
302 sg_dma_address(&dma->sglist[0]) = dma->bus_addr
304 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
305 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
308 if (NULL == dma->sglist) {
309 dprintk(1, "scatterlist is NULL\n");
312 if (!dma->bus_addr) {
313 dma->sglen = dma_map_sg(dev, dma->sglist,
314 dma->nr_pages, dma->direction);
315 if (0 == dma->sglen) {
317 "%s: videobuf_map_sg failed\n", __func__);
328 int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
330 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
335 dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction);
343 EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
345 int videobuf_dma_free(struct videobuf_dmabuf *dma)
348 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
352 for (i = 0; i < dma->nr_pages; i++)
353 page_cache_release(dma->pages[i]);
359 for (i = 0; i < dma->nr_pages; i++) {
362 addr = page_address(dma->vaddr_pages[i]);
363 dma_free_coherent(dma->dev, PAGE_SIZE, addr,
366 kfree(dma->dma_addr);
367 dma->dma_addr = NULL;
368 kfree(dma->vaddr_pages);
369 dma->vaddr_pages = NULL;
376 dma->direction = DMA_NONE;
380 EXPORT_SYMBOL_GPL(videobuf_dma_free);
382 /* --------------------------------------------------------------------- */
384 static void videobuf_vm_open(struct vm_area_struct *vma)
386 struct videobuf_mapping *map = vma->vm_private_data;
388 dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
389 map->count, vma->vm_start, vma->vm_end);
394 static void videobuf_vm_close(struct vm_area_struct *vma)
396 struct videobuf_mapping *map = vma->vm_private_data;
397 struct videobuf_queue *q = map->q;
398 struct videobuf_dma_sg_memory *mem;
401 dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
402 map->count, vma->vm_start, vma->vm_end);
405 if (0 == map->count) {
406 dprintk(1, "munmap %p q=%p\n", map, q);
407 videobuf_queue_lock(q);
408 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
409 if (NULL == q->bufs[i])
411 mem = q->bufs[i]->priv;
415 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
417 if (q->bufs[i]->map != map)
419 q->bufs[i]->map = NULL;
420 q->bufs[i]->baddr = 0;
421 q->ops->buf_release(q, q->bufs[i]);
423 videobuf_queue_unlock(q);
430 * Get a anonymous page for the mapping. Make sure we can DMA to that
431 * memory location with 32bit PCI devices (i.e. don't use highmem for
432 * now ...). Bounce buffers don't work very well for the data rates
435 static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
439 dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
440 (unsigned long)vmf->virtual_address,
441 vma->vm_start, vma->vm_end);
443 page = alloc_page(GFP_USER | __GFP_DMA32);
446 clear_user_highpage(page, (unsigned long)vmf->virtual_address);
452 static const struct vm_operations_struct videobuf_vm_ops = {
453 .open = videobuf_vm_open,
454 .close = videobuf_vm_close,
455 .fault = videobuf_vm_fault,
458 /* ---------------------------------------------------------------------
459 * SG handlers for the generic methods
462 /* Allocated area consists on 3 parts:
464 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
465 struct videobuf_dma_sg_memory
468 static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
470 struct videobuf_dma_sg_memory *mem;
471 struct videobuf_buffer *vb;
473 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
477 mem = vb->priv = ((char *)vb) + size;
478 mem->magic = MAGIC_SG_MEM;
480 videobuf_dma_init(&mem->dma);
482 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
483 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
484 mem, (long)sizeof(*mem));
489 static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
491 struct videobuf_dma_sg_memory *mem = buf->priv;
494 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
496 return mem->dma.vaddr;
499 static int __videobuf_iolock(struct videobuf_queue *q,
500 struct videobuf_buffer *vb,
501 struct v4l2_framebuffer *fbuf)
505 struct videobuf_dma_sg_memory *mem = vb->priv;
508 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
511 mem->dma.dev = q->dev;
513 WARN_ON(mem->dma.dev != q->dev);
515 switch (vb->memory) {
516 case V4L2_MEMORY_MMAP:
517 case V4L2_MEMORY_USERPTR:
518 if (0 == vb->baddr) {
519 /* no userspace addr -- kernel bounce buffer */
520 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
521 err = videobuf_dma_init_kernel(&mem->dma,
526 } else if (vb->memory == V4L2_MEMORY_USERPTR) {
527 /* dma directly to userspace */
528 err = videobuf_dma_init_user(&mem->dma,
530 vb->baddr, vb->bsize);
534 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
535 buffers can only be called from videobuf_qbuf
536 we take current->mm->mmap_sem there, to prevent
537 locking inversion, so don't take it here */
539 err = videobuf_dma_init_user_locked(&mem->dma,
541 vb->baddr, vb->bsize);
546 case V4L2_MEMORY_OVERLAY:
549 /* FIXME: need sanity checks for vb->boff */
551 * Using a double cast to avoid compiler warnings when
552 * building for PAE. Compiler doesn't like direct casting
553 * of a 32 bit ptr to 64 bit integer.
555 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
556 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
557 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
565 err = videobuf_dma_map(q->dev, &mem->dma);
572 static int __videobuf_sync(struct videobuf_queue *q,
573 struct videobuf_buffer *buf)
575 struct videobuf_dma_sg_memory *mem = buf->priv;
576 BUG_ON(!mem || !mem->dma.sglen);
578 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
579 MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF);
581 dma_sync_sg_for_cpu(q->dev, mem->dma.sglist,
582 mem->dma.sglen, mem->dma.direction);
587 static int __videobuf_mmap_mapper(struct videobuf_queue *q,
588 struct videobuf_buffer *buf,
589 struct vm_area_struct *vma)
591 struct videobuf_dma_sg_memory *mem = buf->priv;
592 struct videobuf_mapping *map;
593 unsigned int first, last, size = 0, i;
599 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
601 /* look for first buffer to map */
602 for (first = 0; first < VIDEO_MAX_FRAME; first++) {
603 if (buf == q->bufs[first]) {
604 size = PAGE_ALIGN(q->bufs[first]->bsize);
609 /* paranoia, should never happen since buf is always valid. */
611 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
612 (vma->vm_pgoff << PAGE_SHIFT));
618 /* create mapping + update buffer list */
620 map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
625 for (i = first; i <= last; i++) {
626 if (NULL == q->bufs[i])
628 q->bufs[i]->map = map;
629 q->bufs[i]->baddr = vma->vm_start + size;
630 size += PAGE_ALIGN(q->bufs[i]->bsize);
635 vma->vm_ops = &videobuf_vm_ops;
636 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
637 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
638 vma->vm_private_data = map;
639 dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
640 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last);
647 static struct videobuf_qtype_ops sg_ops = {
648 .magic = MAGIC_QTYPE_OPS,
650 .alloc_vb = __videobuf_alloc_vb,
651 .iolock = __videobuf_iolock,
652 .sync = __videobuf_sync,
653 .mmap_mapper = __videobuf_mmap_mapper,
654 .vaddr = __videobuf_to_vaddr,
657 void *videobuf_sg_alloc(size_t size)
659 struct videobuf_queue q;
661 /* Required to make generic handler to call __videobuf_alloc */
666 return videobuf_alloc_vb(&q);
668 EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
670 void videobuf_queue_sg_init(struct videobuf_queue *q,
671 const struct videobuf_queue_ops *ops,
674 enum v4l2_buf_type type,
675 enum v4l2_field field,
678 struct mutex *ext_lock)
680 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
681 priv, &sg_ops, ext_lock);
683 EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);