/drivers/media/video/videobuf-dma-sg.c
C | 632 lines | 464 code | 105 blank | 63 comment | 81 complexity | 33867bf56d7d891a956ff5bb513808b8 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
1/*
2 * helper functions for SG DMA video4linux capture buffers
3 *
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.
8 *
9 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
10 *
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
15 *
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
19 */
20
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>
27
28#include <linux/dma-mapping.h>
29#include <linux/vmalloc.h>
30#include <linux/pagemap.h>
31#include <linux/scatterlist.h>
32#include <asm/page.h>
33#include <asm/pgtable.h>
34
35#include <media/videobuf-dma-sg.h>
36
37#define MAGIC_DMABUF 0x19721112
38#define MAGIC_SG_MEM 0x17890714
39
40#define MAGIC_CHECK(is, should) \
41 if (unlikely((is) != (should))) { \
42 printk(KERN_ERR "magic mismatch: %x (expected %x)\n", \
43 is, should); \
44 BUG(); \
45 }
46
47static int debug;
48module_param(debug, int, 0644);
49
50MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers");
51MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
52MODULE_LICENSE("GPL");
53
54#define dprintk(level, fmt, arg...) \
55 if (debug >= level) \
56 printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)
57
58/* --------------------------------------------------------------------- */
59
60/*
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.
64 */
65static struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt,
66 int nr_pages)
67{
68 struct scatterlist *sglist;
69 struct page *pg;
70 int i;
71
72 sglist = vzalloc(nr_pages * sizeof(*sglist));
73 if (NULL == sglist)
74 return NULL;
75 sg_init_table(sglist, nr_pages);
76 for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
77 pg = vmalloc_to_page(virt);
78 if (NULL == pg)
79 goto err;
80 BUG_ON(PageHighMem(pg));
81 sg_set_page(&sglist[i], pg, PAGE_SIZE, 0);
82 }
83 return sglist;
84
85err:
86 vfree(sglist);
87 return NULL;
88}
89
90/*
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.
94 */
95static struct scatterlist *videobuf_pages_to_sg(struct page **pages,
96 int nr_pages, int offset, size_t size)
97{
98 struct scatterlist *sglist;
99 int i;
100
101 if (NULL == pages[0])
102 return NULL;
103 sglist = vmalloc(nr_pages * sizeof(*sglist));
104 if (NULL == sglist)
105 return NULL;
106 sg_init_table(sglist, nr_pages);
107
108 if (PageHighMem(pages[0]))
109 /* DMA to highmem pages might not work */
110 goto highmem;
111 sg_set_page(&sglist[0], pages[0], PAGE_SIZE - offset, offset);
112 size -= PAGE_SIZE - offset;
113 for (i = 1; i < nr_pages; i++) {
114 if (NULL == pages[i])
115 goto nopage;
116 if (PageHighMem(pages[i]))
117 goto highmem;
118 sg_set_page(&sglist[i], pages[i], min_t(size_t, PAGE_SIZE, size), 0);
119 size -= min_t(size_t, PAGE_SIZE, size);
120 }
121 return sglist;
122
123nopage:
124 dprintk(2, "sgl: oops - no page\n");
125 vfree(sglist);
126 return NULL;
127
128highmem:
129 dprintk(2, "sgl: oops - highmem page\n");
130 vfree(sglist);
131 return NULL;
132}
133
134/* --------------------------------------------------------------------- */
135
136struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf)
137{
138 struct videobuf_dma_sg_memory *mem = buf->priv;
139 BUG_ON(!mem);
140
141 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
142
143 return &mem->dma;
144}
145EXPORT_SYMBOL_GPL(videobuf_to_dma);
146
147void videobuf_dma_init(struct videobuf_dmabuf *dma)
148{
149 memset(dma, 0, sizeof(*dma));
150 dma->magic = MAGIC_DMABUF;
151}
152EXPORT_SYMBOL_GPL(videobuf_dma_init);
153
154static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
155 int direction, unsigned long data, unsigned long size)
156{
157 unsigned long first, last;
158 int err, rw = 0;
159
160 dma->direction = direction;
161 switch (dma->direction) {
162 case DMA_FROM_DEVICE:
163 rw = READ;
164 break;
165 case DMA_TO_DEVICE:
166 rw = WRITE;
167 break;
168 default:
169 BUG();
170 }
171
172 first = (data & PAGE_MASK) >> PAGE_SHIFT;
173 last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
174 dma->offset = data & ~PAGE_MASK;
175 dma->size = size;
176 dma->nr_pages = last-first+1;
177 dma->pages = kmalloc(dma->nr_pages * sizeof(struct page *), GFP_KERNEL);
178 if (NULL == dma->pages)
179 return -ENOMEM;
180
181 dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
182 data, size, dma->nr_pages);
183
184 err = get_user_pages(current, current->mm,
185 data & PAGE_MASK, dma->nr_pages,
186 rw == READ, 1, /* force */
187 dma->pages, NULL);
188
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;
193 }
194 return 0;
195}
196
197int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
198 unsigned long data, unsigned long size)
199{
200 int ret;
201
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);
205
206 return ret;
207}
208EXPORT_SYMBOL_GPL(videobuf_dma_init_user);
209
210int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
211 int nr_pages)
212{
213 dprintk(1, "init kernel [%d pages]\n", nr_pages);
214
215 dma->direction = direction;
216 dma->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT);
217 if (NULL == dma->vaddr) {
218 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
219 return -ENOMEM;
220 }
221
222 dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
223 (unsigned long)dma->vaddr,
224 nr_pages << PAGE_SHIFT);
225
226 memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT);
227 dma->nr_pages = nr_pages;
228
229 return 0;
230}
231EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel);
232
233int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
234 dma_addr_t addr, int nr_pages)
235{
236 dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n",
237 nr_pages, (unsigned long)addr);
238 dma->direction = direction;
239
240 if (0 == addr)
241 return -EINVAL;
242
243 dma->bus_addr = addr;
244 dma->nr_pages = nr_pages;
245
246 return 0;
247}
248EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay);
249
250int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
251{
252 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
253 BUG_ON(0 == dma->nr_pages);
254
255 if (dma->pages) {
256 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
257 dma->offset, dma->size);
258 }
259 if (dma->vaddr) {
260 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr,
261 dma->nr_pages);
262 }
263 if (dma->bus_addr) {
264 dma->sglist = vmalloc(sizeof(*dma->sglist));
265 if (NULL != dma->sglist) {
266 dma->sglen = 1;
267 sg_dma_address(&dma->sglist[0]) = dma->bus_addr
268 & PAGE_MASK;
269 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
270 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
271 }
272 }
273 if (NULL == dma->sglist) {
274 dprintk(1, "scatterlist is NULL\n");
275 return -ENOMEM;
276 }
277 if (!dma->bus_addr) {
278 dma->sglen = dma_map_sg(dev, dma->sglist,
279 dma->nr_pages, dma->direction);
280 if (0 == dma->sglen) {
281 printk(KERN_WARNING
282 "%s: videobuf_map_sg failed\n", __func__);
283 vfree(dma->sglist);
284 dma->sglist = NULL;
285 dma->sglen = 0;
286 return -ENOMEM;
287 }
288 }
289
290 return 0;
291}
292EXPORT_SYMBOL_GPL(videobuf_dma_map);
293
294int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
295{
296 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
297
298 if (!dma->sglen)
299 return 0;
300
301 dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction);
302
303 vfree(dma->sglist);
304 dma->sglist = NULL;
305 dma->sglen = 0;
306
307 return 0;
308}
309EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
310
311int videobuf_dma_free(struct videobuf_dmabuf *dma)
312{
313 int i;
314 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
315 BUG_ON(dma->sglen);
316
317 if (dma->pages) {
318 for (i = 0; i < dma->nr_pages; i++)
319 page_cache_release(dma->pages[i]);
320 kfree(dma->pages);
321 dma->pages = NULL;
322 }
323
324 vfree(dma->vaddr);
325 dma->vaddr = NULL;
326
327 if (dma->bus_addr)
328 dma->bus_addr = 0;
329 dma->direction = DMA_NONE;
330
331 return 0;
332}
333EXPORT_SYMBOL_GPL(videobuf_dma_free);
334
335/* --------------------------------------------------------------------- */
336
337static void videobuf_vm_open(struct vm_area_struct *vma)
338{
339 struct videobuf_mapping *map = vma->vm_private_data;
340
341 dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
342 map->count, vma->vm_start, vma->vm_end);
343
344 map->count++;
345}
346
347static void videobuf_vm_close(struct vm_area_struct *vma)
348{
349 struct videobuf_mapping *map = vma->vm_private_data;
350 struct videobuf_queue *q = map->q;
351 struct videobuf_dma_sg_memory *mem;
352 int i;
353
354 dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
355 map->count, vma->vm_start, vma->vm_end);
356
357 map->count--;
358 if (0 == map->count) {
359 dprintk(1, "munmap %p q=%p\n", map, q);
360 videobuf_queue_lock(q);
361 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
362 if (NULL == q->bufs[i])
363 continue;
364 mem = q->bufs[i]->priv;
365 if (!mem)
366 continue;
367
368 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
369
370 if (q->bufs[i]->map != map)
371 continue;
372 q->bufs[i]->map = NULL;
373 q->bufs[i]->baddr = 0;
374 q->ops->buf_release(q, q->bufs[i]);
375 }
376 videobuf_queue_unlock(q);
377 kfree(map);
378 }
379 return;
380}
381
382/*
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
386 * video capture has.
387 */
388static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
389{
390 struct page *page;
391
392 dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
393 (unsigned long)vmf->virtual_address,
394 vma->vm_start, vma->vm_end);
395
396 page = alloc_page(GFP_USER | __GFP_DMA32);
397 if (!page)
398 return VM_FAULT_OOM;
399 clear_user_highpage(page, (unsigned long)vmf->virtual_address);
400 vmf->page = page;
401
402 return 0;
403}
404
405static const struct vm_operations_struct videobuf_vm_ops = {
406 .open = videobuf_vm_open,
407 .close = videobuf_vm_close,
408 .fault = videobuf_vm_fault,
409};
410
411/* ---------------------------------------------------------------------
412 * SG handlers for the generic methods
413 */
414
415/* Allocated area consists on 3 parts:
416 struct video_buffer
417 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
418 struct videobuf_dma_sg_memory
419 */
420
421static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
422{
423 struct videobuf_dma_sg_memory *mem;
424 struct videobuf_buffer *vb;
425
426 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
427 if (!vb)
428 return vb;
429
430 mem = vb->priv = ((char *)vb) + size;
431 mem->magic = MAGIC_SG_MEM;
432
433 videobuf_dma_init(&mem->dma);
434
435 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
436 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
437 mem, (long)sizeof(*mem));
438
439 return vb;
440}
441
442static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
443{
444 struct videobuf_dma_sg_memory *mem = buf->priv;
445 BUG_ON(!mem);
446
447 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
448
449 return mem->dma.vaddr;
450}
451
452static int __videobuf_iolock(struct videobuf_queue *q,
453 struct videobuf_buffer *vb,
454 struct v4l2_framebuffer *fbuf)
455{
456 int err, pages;
457 dma_addr_t bus;
458 struct videobuf_dma_sg_memory *mem = vb->priv;
459 BUG_ON(!mem);
460
461 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
462
463 switch (vb->memory) {
464 case V4L2_MEMORY_MMAP:
465 case V4L2_MEMORY_USERPTR:
466 if (0 == vb->baddr) {
467 /* no userspace addr -- kernel bounce buffer */
468 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
469 err = videobuf_dma_init_kernel(&mem->dma,
470 DMA_FROM_DEVICE,
471 pages);
472 if (0 != err)
473 return err;
474 } else if (vb->memory == V4L2_MEMORY_USERPTR) {
475 /* dma directly to userspace */
476 err = videobuf_dma_init_user(&mem->dma,
477 DMA_FROM_DEVICE,
478 vb->baddr, vb->bsize);
479 if (0 != err)
480 return err;
481 } else {
482 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
483 buffers can only be called from videobuf_qbuf
484 we take current->mm->mmap_sem there, to prevent
485 locking inversion, so don't take it here */
486
487 err = videobuf_dma_init_user_locked(&mem->dma,
488 DMA_FROM_DEVICE,
489 vb->baddr, vb->bsize);
490 if (0 != err)
491 return err;
492 }
493 break;
494 case V4L2_MEMORY_OVERLAY:
495 if (NULL == fbuf)
496 return -EINVAL;
497 /* FIXME: need sanity checks for vb->boff */
498 /*
499 * Using a double cast to avoid compiler warnings when
500 * building for PAE. Compiler doesn't like direct casting
501 * of a 32 bit ptr to 64 bit integer.
502 */
503 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
504 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
505 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
506 bus, pages);
507 if (0 != err)
508 return err;
509 break;
510 default:
511 BUG();
512 }
513 err = videobuf_dma_map(q->dev, &mem->dma);
514 if (0 != err)
515 return err;
516
517 return 0;
518}
519
520static int __videobuf_sync(struct videobuf_queue *q,
521 struct videobuf_buffer *buf)
522{
523 struct videobuf_dma_sg_memory *mem = buf->priv;
524 BUG_ON(!mem || !mem->dma.sglen);
525
526 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
527 MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF);
528
529 dma_sync_sg_for_cpu(q->dev, mem->dma.sglist,
530 mem->dma.sglen, mem->dma.direction);
531
532 return 0;
533}
534
535static int __videobuf_mmap_mapper(struct videobuf_queue *q,
536 struct videobuf_buffer *buf,
537 struct vm_area_struct *vma)
538{
539 struct videobuf_dma_sg_memory *mem = buf->priv;
540 struct videobuf_mapping *map;
541 unsigned int first, last, size = 0, i;
542 int retval;
543
544 retval = -EINVAL;
545
546 BUG_ON(!mem);
547 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
548
549 /* look for first buffer to map */
550 for (first = 0; first < VIDEO_MAX_FRAME; first++) {
551 if (buf == q->bufs[first]) {
552 size = PAGE_ALIGN(q->bufs[first]->bsize);
553 break;
554 }
555 }
556
557 /* paranoia, should never happen since buf is always valid. */
558 if (!size) {
559 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
560 (vma->vm_pgoff << PAGE_SHIFT));
561 goto done;
562 }
563
564 last = first;
565
566 /* create mapping + update buffer list */
567 retval = -ENOMEM;
568 map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
569 if (NULL == map)
570 goto done;
571
572 size = 0;
573 for (i = first; i <= last; i++) {
574 if (NULL == q->bufs[i])
575 continue;
576 q->bufs[i]->map = map;
577 q->bufs[i]->baddr = vma->vm_start + size;
578 size += PAGE_ALIGN(q->bufs[i]->bsize);
579 }
580
581 map->count = 1;
582 map->q = q;
583 vma->vm_ops = &videobuf_vm_ops;
584 vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
585 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
586 vma->vm_private_data = map;
587 dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
588 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last);
589 retval = 0;
590
591done:
592 return retval;
593}
594
595static struct videobuf_qtype_ops sg_ops = {
596 .magic = MAGIC_QTYPE_OPS,
597
598 .alloc_vb = __videobuf_alloc_vb,
599 .iolock = __videobuf_iolock,
600 .sync = __videobuf_sync,
601 .mmap_mapper = __videobuf_mmap_mapper,
602 .vaddr = __videobuf_to_vaddr,
603};
604
605void *videobuf_sg_alloc(size_t size)
606{
607 struct videobuf_queue q;
608
609 /* Required to make generic handler to call __videobuf_alloc */
610 q.int_ops = &sg_ops;
611
612 q.msize = size;
613
614 return videobuf_alloc_vb(&q);
615}
616EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
617
618void videobuf_queue_sg_init(struct videobuf_queue *q,
619 const struct videobuf_queue_ops *ops,
620 struct device *dev,
621 spinlock_t *irqlock,
622 enum v4l2_buf_type type,
623 enum v4l2_field field,
624 unsigned int msize,
625 void *priv,
626 struct mutex *ext_lock)
627{
628 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
629 priv, &sg_ops, ext_lock);
630}
631EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);
632