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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],
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])
116 goto nopage;
117 if (PageHighMem(pages[i]))
118 goto highmem;
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);
121 }
122 return sglist;
123
124nopage:
125 dprintk(2, "sgl: oops - no page\n");
126 vfree(sglist);
127 return NULL;
128
129highmem:
130 dprintk(2, "sgl: oops - highmem page\n");
131 vfree(sglist);
132 return NULL;
133}
134
135/* --------------------------------------------------------------------- */
136
137struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf)
138{
139 struct videobuf_dma_sg_memory *mem = buf->priv;
140 BUG_ON(!mem);
141
142 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
143
144 return &mem->dma;
145}
146EXPORT_SYMBOL_GPL(videobuf_to_dma);
147
148void videobuf_dma_init(struct videobuf_dmabuf *dma)
149{
150 memset(dma, 0, sizeof(*dma));
151 dma->magic = MAGIC_DMABUF;
152}
153EXPORT_SYMBOL_GPL(videobuf_dma_init);
154
155static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
156 int direction, unsigned long data, unsigned long size)
157{
158 unsigned long first, last;
159 int err, rw = 0;
160
161 dma->direction = direction;
162 switch (dma->direction) {
163 case DMA_FROM_DEVICE:
164 rw = READ;
165 break;
166 case DMA_TO_DEVICE:
167 rw = WRITE;
168 break;
169 default:
170 BUG();
171 }
172
173 first = (data & PAGE_MASK) >> PAGE_SHIFT;
174 last = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
175 dma->offset = data & ~PAGE_MASK;
176 dma->size = size;
177 dma->nr_pages = last-first+1;
178 dma->pages = kmalloc(dma->nr_pages * sizeof(struct page *), GFP_KERNEL);
179 if (NULL == dma->pages)
180 return -ENOMEM;
181
182 dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
183 data, size, dma->nr_pages);
184
185 err = get_user_pages(current, current->mm,
186 data & PAGE_MASK, dma->nr_pages,
187 rw == READ, 1, /* force */
188 dma->pages, NULL);
189
190 if (err != dma->nr_pages) {
191 dma->nr_pages = (err >= 0) ? err : 0;
192 dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages);
193 return err < 0 ? err : -EINVAL;
194 }
195 return 0;
196}
197
198int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
199 unsigned long data, unsigned long size)
200{
201 int ret;
202
203 down_read(¤t->mm->mmap_sem);
204 ret = videobuf_dma_init_user_locked(dma, direction, data, size);
205 up_read(¤t->mm->mmap_sem);
206
207 return ret;
208}
209EXPORT_SYMBOL_GPL(videobuf_dma_init_user);
210
211int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
212 int nr_pages)
213{
214 dprintk(1, "init kernel [%d pages]\n", nr_pages);
215
216 dma->direction = direction;
217 dma->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT);
218 if (NULL == dma->vaddr) {
219 dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
220 return -ENOMEM;
221 }
222
223 dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
224 (unsigned long)dma->vaddr,
225 nr_pages << PAGE_SHIFT);
226
227 memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT);
228 dma->nr_pages = nr_pages;
229
230 return 0;
231}
232EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel);
233
234int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
235 dma_addr_t addr, int nr_pages)
236{
237 dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n",
238 nr_pages, (unsigned long)addr);
239 dma->direction = direction;
240
241 if (0 == addr)
242 return -EINVAL;
243
244 dma->bus_addr = addr;
245 dma->nr_pages = nr_pages;
246
247 return 0;
248}
249EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay);
250
251int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
252{
253 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
254 BUG_ON(0 == dma->nr_pages);
255
256 if (dma->pages) {
257 dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
258 dma->offset, dma->size);
259 }
260 if (dma->vaddr) {
261 dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr,
262 dma->nr_pages);
263 }
264 if (dma->bus_addr) {
265 dma->sglist = vmalloc(sizeof(*dma->sglist));
266 if (NULL != dma->sglist) {
267 dma->sglen = 1;
268 sg_dma_address(&dma->sglist[0]) = dma->bus_addr
269 & PAGE_MASK;
270 dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
271 sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
272 }
273 }
274 if (NULL == dma->sglist) {
275 dprintk(1, "scatterlist is NULL\n");
276 return -ENOMEM;
277 }
278 if (!dma->bus_addr) {
279 dma->sglen = dma_map_sg(dev, dma->sglist,
280 dma->nr_pages, dma->direction);
281 if (0 == dma->sglen) {
282 printk(KERN_WARNING
283 "%s: videobuf_map_sg failed\n", __func__);
284 vfree(dma->sglist);
285 dma->sglist = NULL;
286 dma->sglen = 0;
287 return -ENOMEM;
288 }
289 }
290
291 return 0;
292}
293EXPORT_SYMBOL_GPL(videobuf_dma_map);
294
295int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
296{
297 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
298
299 if (!dma->sglen)
300 return 0;
301
302 dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction);
303
304 vfree(dma->sglist);
305 dma->sglist = NULL;
306 dma->sglen = 0;
307
308 return 0;
309}
310EXPORT_SYMBOL_GPL(videobuf_dma_unmap);
311
312int videobuf_dma_free(struct videobuf_dmabuf *dma)
313{
314 int i;
315 MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
316 BUG_ON(dma->sglen);
317
318 if (dma->pages) {
319 for (i = 0; i < dma->nr_pages; i++)
320 page_cache_release(dma->pages[i]);
321 kfree(dma->pages);
322 dma->pages = NULL;
323 }
324
325 vfree(dma->vaddr);
326 dma->vaddr = NULL;
327
328 if (dma->bus_addr)
329 dma->bus_addr = 0;
330 dma->direction = DMA_NONE;
331
332 return 0;
333}
334EXPORT_SYMBOL_GPL(videobuf_dma_free);
335
336/* --------------------------------------------------------------------- */
337
338static void videobuf_vm_open(struct vm_area_struct *vma)
339{
340 struct videobuf_mapping *map = vma->vm_private_data;
341
342 dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
343 map->count, vma->vm_start, vma->vm_end);
344
345 map->count++;
346}
347
348static void videobuf_vm_close(struct vm_area_struct *vma)
349{
350 struct videobuf_mapping *map = vma->vm_private_data;
351 struct videobuf_queue *q = map->q;
352 struct videobuf_dma_sg_memory *mem;
353 int i;
354
355 dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
356 map->count, vma->vm_start, vma->vm_end);
357
358 map->count--;
359 if (0 == map->count) {
360 dprintk(1, "munmap %p q=%p\n", map, q);
361 videobuf_queue_lock(q);
362 for (i = 0; i < VIDEO_MAX_FRAME; i++) {
363 if (NULL == q->bufs[i])
364 continue;
365 mem = q->bufs[i]->priv;
366 if (!mem)
367 continue;
368
369 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
370
371 if (q->bufs[i]->map != map)
372 continue;
373 q->bufs[i]->map = NULL;
374 q->bufs[i]->baddr = 0;
375 q->ops->buf_release(q, q->bufs[i]);
376 }
377 videobuf_queue_unlock(q);
378 kfree(map);
379 }
380 return;
381}
382
383/*
384 * Get a anonymous page for the mapping. Make sure we can DMA to that
385 * memory location with 32bit PCI devices (i.e. don't use highmem for
386 * now ...). Bounce buffers don't work very well for the data rates
387 * video capture has.
388 */
389static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
390{
391 struct page *page;
392
393 dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
394 (unsigned long)vmf->virtual_address,
395 vma->vm_start, vma->vm_end);
396
397 page = alloc_page(GFP_USER | __GFP_DMA32);
398 if (!page)
399 return VM_FAULT_OOM;
400 clear_user_highpage(page, (unsigned long)vmf->virtual_address);
401 vmf->page = page;
402
403 return 0;
404}
405
406static const struct vm_operations_struct videobuf_vm_ops = {
407 .open = videobuf_vm_open,
408 .close = videobuf_vm_close,
409 .fault = videobuf_vm_fault,
410};
411
412/* ---------------------------------------------------------------------
413 * SG handlers for the generic methods
414 */
415
416/* Allocated area consists on 3 parts:
417 struct video_buffer
418 struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
419 struct videobuf_dma_sg_memory
420 */
421
422static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
423{
424 struct videobuf_dma_sg_memory *mem;
425 struct videobuf_buffer *vb;
426
427 vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
428 if (!vb)
429 return vb;
430
431 mem = vb->priv = ((char *)vb) + size;
432 mem->magic = MAGIC_SG_MEM;
433
434 videobuf_dma_init(&mem->dma);
435
436 dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
437 __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
438 mem, (long)sizeof(*mem));
439
440 return vb;
441}
442
443static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
444{
445 struct videobuf_dma_sg_memory *mem = buf->priv;
446 BUG_ON(!mem);
447
448 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
449
450 return mem->dma.vaddr;
451}
452
453static int __videobuf_iolock(struct videobuf_queue *q,
454 struct videobuf_buffer *vb,
455 struct v4l2_framebuffer *fbuf)
456{
457 int err, pages;
458 dma_addr_t bus;
459 struct videobuf_dma_sg_memory *mem = vb->priv;
460 BUG_ON(!mem);
461
462 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
463
464 switch (vb->memory) {
465 case V4L2_MEMORY_MMAP:
466 case V4L2_MEMORY_USERPTR:
467 if (0 == vb->baddr) {
468 /* no userspace addr -- kernel bounce buffer */
469 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
470 err = videobuf_dma_init_kernel(&mem->dma,
471 DMA_FROM_DEVICE,
472 pages);
473 if (0 != err)
474 return err;
475 } else if (vb->memory == V4L2_MEMORY_USERPTR) {
476 /* dma directly to userspace */
477 err = videobuf_dma_init_user(&mem->dma,
478 DMA_FROM_DEVICE,
479 vb->baddr, vb->bsize);
480 if (0 != err)
481 return err;
482 } else {
483 /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
484 buffers can only be called from videobuf_qbuf
485 we take current->mm->mmap_sem there, to prevent
486 locking inversion, so don't take it here */
487
488 err = videobuf_dma_init_user_locked(&mem->dma,
489 DMA_FROM_DEVICE,
490 vb->baddr, vb->bsize);
491 if (0 != err)
492 return err;
493 }
494 break;
495 case V4L2_MEMORY_OVERLAY:
496 if (NULL == fbuf)
497 return -EINVAL;
498 /* FIXME: need sanity checks for vb->boff */
499 /*
500 * Using a double cast to avoid compiler warnings when
501 * building for PAE. Compiler doesn't like direct casting
502 * of a 32 bit ptr to 64 bit integer.
503 */
504 bus = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
505 pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
506 err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
507 bus, pages);
508 if (0 != err)
509 return err;
510 break;
511 default:
512 BUG();
513 }
514 err = videobuf_dma_map(q->dev, &mem->dma);
515 if (0 != err)
516 return err;
517
518 return 0;
519}
520
521static int __videobuf_sync(struct videobuf_queue *q,
522 struct videobuf_buffer *buf)
523{
524 struct videobuf_dma_sg_memory *mem = buf->priv;
525 BUG_ON(!mem || !mem->dma.sglen);
526
527 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
528 MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF);
529
530 dma_sync_sg_for_cpu(q->dev, mem->dma.sglist,
531 mem->dma.sglen, mem->dma.direction);
532
533 return 0;
534}
535
536static int __videobuf_mmap_mapper(struct videobuf_queue *q,
537 struct videobuf_buffer *buf,
538 struct vm_area_struct *vma)
539{
540 struct videobuf_dma_sg_memory *mem = buf->priv;
541 struct videobuf_mapping *map;
542 unsigned int first, last, size = 0, i;
543 int retval;
544
545 retval = -EINVAL;
546
547 BUG_ON(!mem);
548 MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
549
550 /* look for first buffer to map */
551 for (first = 0; first < VIDEO_MAX_FRAME; first++) {
552 if (buf == q->bufs[first]) {
553 size = PAGE_ALIGN(q->bufs[first]->bsize);
554 break;
555 }
556 }
557
558 /* paranoia, should never happen since buf is always valid. */
559 if (!size) {
560 dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
561 (vma->vm_pgoff << PAGE_SHIFT));
562 goto done;
563 }
564
565 last = first;
566
567 /* create mapping + update buffer list */
568 retval = -ENOMEM;
569 map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
570 if (NULL == map)
571 goto done;
572
573 size = 0;
574 for (i = first; i <= last; i++) {
575 if (NULL == q->bufs[i])
576 continue;
577 q->bufs[i]->map = map;
578 q->bufs[i]->baddr = vma->vm_start + size;
579 size += PAGE_ALIGN(q->bufs[i]->bsize);
580 }
581
582 map->count = 1;
583 map->q = q;
584 vma->vm_ops = &videobuf_vm_ops;
585 vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
586 vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
587 vma->vm_private_data = map;
588 dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
589 map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last);
590 retval = 0;
591
592done:
593 return retval;
594}
595
596static struct videobuf_qtype_ops sg_ops = {
597 .magic = MAGIC_QTYPE_OPS,
598
599 .alloc_vb = __videobuf_alloc_vb,
600 .iolock = __videobuf_iolock,
601 .sync = __videobuf_sync,
602 .mmap_mapper = __videobuf_mmap_mapper,
603 .vaddr = __videobuf_to_vaddr,
604};
605
606void *videobuf_sg_alloc(size_t size)
607{
608 struct videobuf_queue q;
609
610 /* Required to make generic handler to call __videobuf_alloc */
611 q.int_ops = &sg_ops;
612
613 q.msize = size;
614
615 return videobuf_alloc_vb(&q);
616}
617EXPORT_SYMBOL_GPL(videobuf_sg_alloc);
618
619void videobuf_queue_sg_init(struct videobuf_queue *q,
620 const struct videobuf_queue_ops *ops,
621 struct device *dev,
622 spinlock_t *irqlock,
623 enum v4l2_buf_type type,
624 enum v4l2_field field,
625 unsigned int msize,
626 void *priv,
627 struct mutex *ext_lock)
628{
629 videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
630 priv, &sg_ops, ext_lock);
631}
632EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);
633