2 * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation.
13 #include <linux/module.h>
15 #include <linux/scatterlist.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/vmalloc.h>
20 #include <media/videobuf2-core.h>
21 #include <media/videobuf2-memops.h>
22 #include <media/videobuf2-dma-sg.h>
25 module_param(debug, int, 0644);
27 #define dprintk(level, fmt, arg...) \
30 printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \
33 struct vb2_dma_sg_conf {
37 struct vb2_dma_sg_buf {
41 struct frame_vector *vec;
43 enum dma_data_direction dma_dir;
44 struct sg_table sg_table;
46 * This will point to sg_table when used with the MMAP or USERPTR
47 * memory model, and to the dma_buf sglist when used with the
48 * DMABUF memory model.
50 struct sg_table *dma_sgt;
52 unsigned int num_pages;
54 struct vb2_vmarea_handler handler;
56 struct dma_buf_attachment *db_attach;
59 static void vb2_dma_sg_put(void *buf_priv);
61 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
64 unsigned int last_page = 0;
72 order = get_order(size);
73 /* Dont over allocate*/
74 if ((PAGE_SIZE << order) > size)
79 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
80 __GFP_NOWARN | gfp_flags, order);
86 __free_page(buf->pages[last_page]);
92 split_page(pages, order);
93 for (i = 0; i < (1 << order); i++)
94 buf->pages[last_page++] = &pages[i];
96 size -= PAGE_SIZE << order;
102 static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size,
103 enum dma_data_direction dma_dir, gfp_t gfp_flags)
105 struct vb2_dma_sg_conf *conf = alloc_ctx;
106 struct vb2_dma_sg_buf *buf;
107 struct sg_table *sgt;
110 DEFINE_DMA_ATTRS(attrs);
112 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
114 if (WARN_ON(alloc_ctx == NULL))
116 buf = kzalloc(sizeof *buf, GFP_KERNEL);
121 buf->dma_dir = dma_dir;
124 /* size is already page aligned */
125 buf->num_pages = size >> PAGE_SHIFT;
126 buf->dma_sgt = &buf->sg_table;
128 buf->pages = kzalloc(buf->num_pages * sizeof(struct page *),
131 goto fail_pages_array_alloc;
133 ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
135 goto fail_pages_alloc;
137 ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
138 buf->num_pages, 0, size, GFP_KERNEL);
140 goto fail_table_alloc;
142 /* Prevent the device from being released while the buffer is used */
143 buf->dev = get_device(conf->dev);
145 sgt = &buf->sg_table;
147 * No need to sync to the device, this will happen later when the
148 * prepare() memop is called.
150 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
151 buf->dma_dir, &attrs);
155 buf->handler.refcount = &buf->refcount;
156 buf->handler.put = vb2_dma_sg_put;
157 buf->handler.arg = buf;
159 atomic_inc(&buf->refcount);
161 dprintk(1, "%s: Allocated buffer of %d pages\n",
162 __func__, buf->num_pages);
166 put_device(buf->dev);
167 sg_free_table(buf->dma_sgt);
169 num_pages = buf->num_pages;
171 __free_page(buf->pages[num_pages]);
174 fail_pages_array_alloc:
179 static void vb2_dma_sg_put(void *buf_priv)
181 struct vb2_dma_sg_buf *buf = buf_priv;
182 struct sg_table *sgt = &buf->sg_table;
183 int i = buf->num_pages;
185 if (atomic_dec_and_test(&buf->refcount)) {
186 DEFINE_DMA_ATTRS(attrs);
188 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
189 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
191 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
192 buf->dma_dir, &attrs);
194 vm_unmap_ram(buf->vaddr, buf->num_pages);
195 sg_free_table(buf->dma_sgt);
197 __free_page(buf->pages[i]);
199 put_device(buf->dev);
204 static void vb2_dma_sg_prepare(void *buf_priv)
206 struct vb2_dma_sg_buf *buf = buf_priv;
207 struct sg_table *sgt = buf->dma_sgt;
209 /* DMABUF exporter will flush the cache for us */
213 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
216 static void vb2_dma_sg_finish(void *buf_priv)
218 struct vb2_dma_sg_buf *buf = buf_priv;
219 struct sg_table *sgt = buf->dma_sgt;
221 /* DMABUF exporter will flush the cache for us */
225 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->nents, buf->dma_dir);
228 static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
230 enum dma_data_direction dma_dir)
232 struct vb2_dma_sg_conf *conf = alloc_ctx;
233 struct vb2_dma_sg_buf *buf;
234 struct sg_table *sgt;
235 DEFINE_DMA_ATTRS(attrs);
236 struct frame_vector *vec;
238 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
239 buf = kzalloc(sizeof *buf, GFP_KERNEL);
244 buf->dev = conf->dev;
245 buf->dma_dir = dma_dir;
246 buf->offset = vaddr & ~PAGE_MASK;
248 buf->dma_sgt = &buf->sg_table;
249 vec = vb2_create_framevec(vaddr, size, buf->dma_dir == DMA_FROM_DEVICE);
251 goto userptr_fail_pfnvec;
254 buf->pages = frame_vector_pages(vec);
255 if (IS_ERR(buf->pages))
256 goto userptr_fail_sgtable;
257 buf->num_pages = frame_vector_count(vec);
259 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
260 buf->num_pages, buf->offset, size, 0))
261 goto userptr_fail_sgtable;
263 sgt = &buf->sg_table;
265 * No need to sync to the device, this will happen later when the
266 * prepare() memop is called.
268 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
269 buf->dma_dir, &attrs);
271 goto userptr_fail_map;
276 sg_free_table(&buf->sg_table);
277 userptr_fail_sgtable:
278 vb2_destroy_framevec(vec);
285 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
288 static void vb2_dma_sg_put_userptr(void *buf_priv)
290 struct vb2_dma_sg_buf *buf = buf_priv;
291 struct sg_table *sgt = &buf->sg_table;
292 int i = buf->num_pages;
293 DEFINE_DMA_ATTRS(attrs);
295 dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
297 dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
298 __func__, buf->num_pages);
299 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
302 vm_unmap_ram(buf->vaddr, buf->num_pages);
303 sg_free_table(buf->dma_sgt);
305 if (buf->dma_dir == DMA_FROM_DEVICE)
306 set_page_dirty_lock(buf->pages[i]);
308 vb2_destroy_framevec(buf->vec);
312 static void *vb2_dma_sg_vaddr(void *buf_priv)
314 struct vb2_dma_sg_buf *buf = buf_priv;
320 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
322 buf->vaddr = vm_map_ram(buf->pages,
323 buf->num_pages, -1, PAGE_KERNEL);
326 /* add offset in case userptr is not page-aligned */
327 return buf->vaddr ? buf->vaddr + buf->offset : NULL;
330 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
332 struct vb2_dma_sg_buf *buf = buf_priv;
334 return atomic_read(&buf->refcount);
337 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
339 struct vb2_dma_sg_buf *buf = buf_priv;
340 unsigned long uaddr = vma->vm_start;
341 unsigned long usize = vma->vm_end - vma->vm_start;
345 printk(KERN_ERR "No memory to map\n");
352 ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
354 printk(KERN_ERR "Remapping memory, error: %d\n", ret);
364 * Use common vm_area operations to track buffer refcount.
366 vma->vm_private_data = &buf->handler;
367 vma->vm_ops = &vb2_common_vm_ops;
369 vma->vm_ops->open(vma);
374 /*********************************************/
375 /* DMABUF ops for exporters */
376 /*********************************************/
378 struct vb2_dma_sg_attachment {
380 enum dma_data_direction dma_dir;
383 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
384 struct dma_buf_attachment *dbuf_attach)
386 struct vb2_dma_sg_attachment *attach;
388 struct scatterlist *rd, *wr;
389 struct sg_table *sgt;
390 struct vb2_dma_sg_buf *buf = dbuf->priv;
393 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
398 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
399 * map the same scatter list to multiple attachments at the same time.
401 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
407 rd = buf->dma_sgt->sgl;
409 for (i = 0; i < sgt->orig_nents; ++i) {
410 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
415 attach->dma_dir = DMA_NONE;
416 dbuf_attach->priv = attach;
421 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
422 struct dma_buf_attachment *db_attach)
424 struct vb2_dma_sg_attachment *attach = db_attach->priv;
425 struct sg_table *sgt;
432 /* release the scatterlist cache */
433 if (attach->dma_dir != DMA_NONE)
434 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
438 db_attach->priv = NULL;
441 static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
442 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
444 struct vb2_dma_sg_attachment *attach = db_attach->priv;
445 /* stealing dmabuf mutex to serialize map/unmap operations */
446 struct mutex *lock = &db_attach->dmabuf->lock;
447 struct sg_table *sgt;
452 /* return previously mapped sg table */
453 if (attach->dma_dir == dma_dir) {
458 /* release any previous cache */
459 if (attach->dma_dir != DMA_NONE) {
460 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
462 attach->dma_dir = DMA_NONE;
465 /* mapping to the client with new direction */
466 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
469 pr_err("failed to map scatterlist\n");
471 return ERR_PTR(-EIO);
474 attach->dma_dir = dma_dir;
481 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
482 struct sg_table *sgt, enum dma_data_direction dma_dir)
484 /* nothing to be done here */
487 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
489 /* drop reference obtained in vb2_dma_sg_get_dmabuf */
490 vb2_dma_sg_put(dbuf->priv);
493 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
495 struct vb2_dma_sg_buf *buf = dbuf->priv;
497 return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
500 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
502 struct vb2_dma_sg_buf *buf = dbuf->priv;
504 return vb2_dma_sg_vaddr(buf);
507 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
508 struct vm_area_struct *vma)
510 return vb2_dma_sg_mmap(dbuf->priv, vma);
513 static struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
514 .attach = vb2_dma_sg_dmabuf_ops_attach,
515 .detach = vb2_dma_sg_dmabuf_ops_detach,
516 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
517 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
518 .kmap = vb2_dma_sg_dmabuf_ops_kmap,
519 .kmap_atomic = vb2_dma_sg_dmabuf_ops_kmap,
520 .vmap = vb2_dma_sg_dmabuf_ops_vmap,
521 .mmap = vb2_dma_sg_dmabuf_ops_mmap,
522 .release = vb2_dma_sg_dmabuf_ops_release,
525 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
527 struct vb2_dma_sg_buf *buf = buf_priv;
528 struct dma_buf *dbuf;
529 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
531 exp_info.ops = &vb2_dma_sg_dmabuf_ops;
532 exp_info.size = buf->size;
533 exp_info.flags = flags;
536 if (WARN_ON(!buf->dma_sgt))
539 dbuf = dma_buf_export(&exp_info);
543 /* dmabuf keeps reference to vb2 buffer */
544 atomic_inc(&buf->refcount);
549 /*********************************************/
550 /* callbacks for DMABUF buffers */
551 /*********************************************/
553 static int vb2_dma_sg_map_dmabuf(void *mem_priv)
555 struct vb2_dma_sg_buf *buf = mem_priv;
556 struct sg_table *sgt;
558 if (WARN_ON(!buf->db_attach)) {
559 pr_err("trying to pin a non attached buffer\n");
563 if (WARN_ON(buf->dma_sgt)) {
564 pr_err("dmabuf buffer is already pinned\n");
568 /* get the associated scatterlist for this buffer */
569 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
571 pr_err("Error getting dmabuf scatterlist\n");
581 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
583 struct vb2_dma_sg_buf *buf = mem_priv;
584 struct sg_table *sgt = buf->dma_sgt;
586 if (WARN_ON(!buf->db_attach)) {
587 pr_err("trying to unpin a not attached buffer\n");
592 pr_err("dmabuf buffer is already unpinned\n");
597 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
600 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
605 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
607 struct vb2_dma_sg_buf *buf = mem_priv;
609 /* if vb2 works correctly you should never detach mapped buffer */
610 if (WARN_ON(buf->dma_sgt))
611 vb2_dma_sg_unmap_dmabuf(buf);
613 /* detach this attachment */
614 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
618 static void *vb2_dma_sg_attach_dmabuf(void *alloc_ctx, struct dma_buf *dbuf,
619 unsigned long size, enum dma_data_direction dma_dir)
621 struct vb2_dma_sg_conf *conf = alloc_ctx;
622 struct vb2_dma_sg_buf *buf;
623 struct dma_buf_attachment *dba;
625 if (dbuf->size < size)
626 return ERR_PTR(-EFAULT);
628 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
630 return ERR_PTR(-ENOMEM);
632 buf->dev = conf->dev;
633 /* create attachment for the dmabuf with the user device */
634 dba = dma_buf_attach(dbuf, buf->dev);
636 pr_err("failed to attach dmabuf\n");
641 buf->dma_dir = dma_dir;
643 buf->db_attach = dba;
648 static void *vb2_dma_sg_cookie(void *buf_priv)
650 struct vb2_dma_sg_buf *buf = buf_priv;
655 const struct vb2_mem_ops vb2_dma_sg_memops = {
656 .alloc = vb2_dma_sg_alloc,
657 .put = vb2_dma_sg_put,
658 .get_userptr = vb2_dma_sg_get_userptr,
659 .put_userptr = vb2_dma_sg_put_userptr,
660 .prepare = vb2_dma_sg_prepare,
661 .finish = vb2_dma_sg_finish,
662 .vaddr = vb2_dma_sg_vaddr,
663 .mmap = vb2_dma_sg_mmap,
664 .num_users = vb2_dma_sg_num_users,
665 .get_dmabuf = vb2_dma_sg_get_dmabuf,
666 .map_dmabuf = vb2_dma_sg_map_dmabuf,
667 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
668 .attach_dmabuf = vb2_dma_sg_attach_dmabuf,
669 .detach_dmabuf = vb2_dma_sg_detach_dmabuf,
670 .cookie = vb2_dma_sg_cookie,
672 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
674 void *vb2_dma_sg_init_ctx(struct device *dev)
676 struct vb2_dma_sg_conf *conf;
678 conf = kzalloc(sizeof(*conf), GFP_KERNEL);
680 return ERR_PTR(-ENOMEM);
686 EXPORT_SYMBOL_GPL(vb2_dma_sg_init_ctx);
688 void vb2_dma_sg_cleanup_ctx(void *alloc_ctx)
690 if (!IS_ERR_OR_NULL(alloc_ctx))
693 EXPORT_SYMBOL_GPL(vb2_dma_sg_cleanup_ctx);
695 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
696 MODULE_AUTHOR("Andrzej Pietrasiewicz");
697 MODULE_LICENSE("GPL");