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/refcount.h>
16 #include <linux/scatterlist.h>
17 #include <linux/sched.h>
18 #include <linux/slab.h>
19 #include <linux/vmalloc.h>
21 #include <media/videobuf2-v4l2.h>
22 #include <media/videobuf2-memops.h>
23 #include <media/videobuf2-dma-sg.h>
26 module_param(debug, int, 0644);
28 #define dprintk(level, fmt, arg...) \
31 printk(KERN_DEBUG "vb2-dma-sg: " fmt, ## arg); \
34 struct vb2_dma_sg_buf {
38 struct frame_vector *vec;
40 enum dma_data_direction dma_dir;
41 struct sg_table sg_table;
43 * This will point to sg_table when used with the MMAP or USERPTR
44 * memory model, and to the dma_buf sglist when used with the
45 * DMABUF memory model.
47 struct sg_table *dma_sgt;
49 unsigned int num_pages;
51 struct vb2_vmarea_handler handler;
53 struct dma_buf_attachment *db_attach;
56 static void vb2_dma_sg_put(void *buf_priv);
58 static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
61 unsigned int last_page = 0;
69 order = get_order(size);
70 /* Dont over allocate*/
71 if ((PAGE_SIZE << order) > size)
76 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO |
77 __GFP_NOWARN | gfp_flags, order);
83 __free_page(buf->pages[last_page]);
89 split_page(pages, order);
90 for (i = 0; i < (1 << order); i++)
91 buf->pages[last_page++] = &pages[i];
93 size -= PAGE_SIZE << order;
99 static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
100 unsigned long size, enum dma_data_direction dma_dir,
103 struct vb2_dma_sg_buf *buf;
104 struct sg_table *sgt;
109 return ERR_PTR(-EINVAL);
111 buf = kzalloc(sizeof *buf, GFP_KERNEL);
113 return ERR_PTR(-ENOMEM);
116 buf->dma_dir = dma_dir;
119 /* size is already page aligned */
120 buf->num_pages = size >> PAGE_SHIFT;
121 buf->dma_sgt = &buf->sg_table;
123 buf->pages = kvmalloc_array(buf->num_pages, sizeof(struct page *),
124 GFP_KERNEL | __GFP_ZERO);
126 goto fail_pages_array_alloc;
128 ret = vb2_dma_sg_alloc_compacted(buf, gfp_flags);
130 goto fail_pages_alloc;
132 ret = sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
133 buf->num_pages, 0, size, GFP_KERNEL);
135 goto fail_table_alloc;
137 /* Prevent the device from being released while the buffer is used */
138 buf->dev = get_device(dev);
140 sgt = &buf->sg_table;
142 * No need to sync to the device, this will happen later when the
143 * prepare() memop is called.
145 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
146 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
150 buf->handler.refcount = &buf->refcount;
151 buf->handler.put = vb2_dma_sg_put;
152 buf->handler.arg = buf;
154 refcount_set(&buf->refcount, 1);
156 dprintk(1, "%s: Allocated buffer of %d pages\n",
157 __func__, buf->num_pages);
161 put_device(buf->dev);
162 sg_free_table(buf->dma_sgt);
164 num_pages = buf->num_pages;
166 __free_page(buf->pages[num_pages]);
169 fail_pages_array_alloc:
171 return ERR_PTR(-ENOMEM);
174 static void vb2_dma_sg_put(void *buf_priv)
176 struct vb2_dma_sg_buf *buf = buf_priv;
177 struct sg_table *sgt = &buf->sg_table;
178 int i = buf->num_pages;
180 if (refcount_dec_and_test(&buf->refcount)) {
181 dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
183 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
184 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
186 vm_unmap_ram(buf->vaddr, buf->num_pages);
187 sg_free_table(buf->dma_sgt);
189 __free_page(buf->pages[i]);
191 put_device(buf->dev);
196 static void vb2_dma_sg_prepare(void *buf_priv)
198 struct vb2_dma_sg_buf *buf = buf_priv;
199 struct sg_table *sgt = buf->dma_sgt;
201 /* DMABUF exporter will flush the cache for us */
205 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
209 static void vb2_dma_sg_finish(void *buf_priv)
211 struct vb2_dma_sg_buf *buf = buf_priv;
212 struct sg_table *sgt = buf->dma_sgt;
214 /* DMABUF exporter will flush the cache for us */
218 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
221 static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
223 enum dma_data_direction dma_dir)
225 struct vb2_dma_sg_buf *buf;
226 struct sg_table *sgt;
227 struct frame_vector *vec;
230 return ERR_PTR(-EINVAL);
232 buf = kzalloc(sizeof *buf, GFP_KERNEL);
234 return ERR_PTR(-ENOMEM);
238 buf->dma_dir = dma_dir;
239 buf->offset = vaddr & ~PAGE_MASK;
241 buf->dma_sgt = &buf->sg_table;
242 vec = vb2_create_framevec(vaddr, size, dma_dir == DMA_FROM_DEVICE ||
243 dma_dir == DMA_BIDIRECTIONAL);
245 goto userptr_fail_pfnvec;
248 buf->pages = frame_vector_pages(vec);
249 if (IS_ERR(buf->pages))
250 goto userptr_fail_sgtable;
251 buf->num_pages = frame_vector_count(vec);
253 if (sg_alloc_table_from_pages(buf->dma_sgt, buf->pages,
254 buf->num_pages, buf->offset, size, 0))
255 goto userptr_fail_sgtable;
257 sgt = &buf->sg_table;
259 * No need to sync to the device, this will happen later when the
260 * prepare() memop is called.
262 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
263 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
265 goto userptr_fail_map;
270 sg_free_table(&buf->sg_table);
271 userptr_fail_sgtable:
272 vb2_destroy_framevec(vec);
275 return ERR_PTR(-ENOMEM);
279 * @put_userptr: inform the allocator that a USERPTR buffer will no longer
282 static void vb2_dma_sg_put_userptr(void *buf_priv)
284 struct vb2_dma_sg_buf *buf = buf_priv;
285 struct sg_table *sgt = &buf->sg_table;
286 int i = buf->num_pages;
288 dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
289 __func__, buf->num_pages);
290 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
291 DMA_ATTR_SKIP_CPU_SYNC);
293 vm_unmap_ram(buf->vaddr, buf->num_pages);
294 sg_free_table(buf->dma_sgt);
296 if (buf->dma_dir == DMA_FROM_DEVICE ||
297 buf->dma_dir == DMA_BIDIRECTIONAL)
298 set_page_dirty_lock(buf->pages[i]);
300 vb2_destroy_framevec(buf->vec);
304 static void *vb2_dma_sg_vaddr(void *buf_priv)
306 struct vb2_dma_sg_buf *buf = buf_priv;
312 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
314 buf->vaddr = vm_map_ram(buf->pages,
315 buf->num_pages, -1, PAGE_KERNEL);
318 /* add offset in case userptr is not page-aligned */
319 return buf->vaddr ? buf->vaddr + buf->offset : NULL;
322 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
324 struct vb2_dma_sg_buf *buf = buf_priv;
326 return refcount_read(&buf->refcount);
329 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
331 struct vb2_dma_sg_buf *buf = buf_priv;
332 unsigned long uaddr = vma->vm_start;
333 unsigned long usize = vma->vm_end - vma->vm_start;
337 printk(KERN_ERR "No memory to map\n");
344 ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
346 printk(KERN_ERR "Remapping memory, error: %d\n", ret);
356 * Use common vm_area operations to track buffer refcount.
358 vma->vm_private_data = &buf->handler;
359 vma->vm_ops = &vb2_common_vm_ops;
361 vma->vm_ops->open(vma);
366 /*********************************************/
367 /* DMABUF ops for exporters */
368 /*********************************************/
370 struct vb2_dma_sg_attachment {
372 enum dma_data_direction dma_dir;
375 static int vb2_dma_sg_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
376 struct dma_buf_attachment *dbuf_attach)
378 struct vb2_dma_sg_attachment *attach;
380 struct scatterlist *rd, *wr;
381 struct sg_table *sgt;
382 struct vb2_dma_sg_buf *buf = dbuf->priv;
385 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
390 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
391 * map the same scatter list to multiple attachments at the same time.
393 ret = sg_alloc_table(sgt, buf->dma_sgt->orig_nents, GFP_KERNEL);
399 rd = buf->dma_sgt->sgl;
401 for (i = 0; i < sgt->orig_nents; ++i) {
402 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
407 attach->dma_dir = DMA_NONE;
408 dbuf_attach->priv = attach;
413 static void vb2_dma_sg_dmabuf_ops_detach(struct dma_buf *dbuf,
414 struct dma_buf_attachment *db_attach)
416 struct vb2_dma_sg_attachment *attach = db_attach->priv;
417 struct sg_table *sgt;
424 /* release the scatterlist cache */
425 if (attach->dma_dir != DMA_NONE)
426 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
430 db_attach->priv = NULL;
433 static struct sg_table *vb2_dma_sg_dmabuf_ops_map(
434 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
436 struct vb2_dma_sg_attachment *attach = db_attach->priv;
437 /* stealing dmabuf mutex to serialize map/unmap operations */
438 struct mutex *lock = &db_attach->dmabuf->lock;
439 struct sg_table *sgt;
444 /* return previously mapped sg table */
445 if (attach->dma_dir == dma_dir) {
450 /* release any previous cache */
451 if (attach->dma_dir != DMA_NONE) {
452 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
454 attach->dma_dir = DMA_NONE;
457 /* mapping to the client with new direction */
458 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
461 pr_err("failed to map scatterlist\n");
463 return ERR_PTR(-EIO);
466 attach->dma_dir = dma_dir;
473 static void vb2_dma_sg_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
474 struct sg_table *sgt, enum dma_data_direction dma_dir)
476 /* nothing to be done here */
479 static void vb2_dma_sg_dmabuf_ops_release(struct dma_buf *dbuf)
481 /* drop reference obtained in vb2_dma_sg_get_dmabuf */
482 vb2_dma_sg_put(dbuf->priv);
485 static void *vb2_dma_sg_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
487 struct vb2_dma_sg_buf *buf = dbuf->priv;
489 return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
492 static void *vb2_dma_sg_dmabuf_ops_vmap(struct dma_buf *dbuf)
494 struct vb2_dma_sg_buf *buf = dbuf->priv;
496 return vb2_dma_sg_vaddr(buf);
499 static int vb2_dma_sg_dmabuf_ops_mmap(struct dma_buf *dbuf,
500 struct vm_area_struct *vma)
502 return vb2_dma_sg_mmap(dbuf->priv, vma);
505 static const struct dma_buf_ops vb2_dma_sg_dmabuf_ops = {
506 .attach = vb2_dma_sg_dmabuf_ops_attach,
507 .detach = vb2_dma_sg_dmabuf_ops_detach,
508 .map_dma_buf = vb2_dma_sg_dmabuf_ops_map,
509 .unmap_dma_buf = vb2_dma_sg_dmabuf_ops_unmap,
510 .map = vb2_dma_sg_dmabuf_ops_kmap,
511 .map_atomic = vb2_dma_sg_dmabuf_ops_kmap,
512 .vmap = vb2_dma_sg_dmabuf_ops_vmap,
513 .mmap = vb2_dma_sg_dmabuf_ops_mmap,
514 .release = vb2_dma_sg_dmabuf_ops_release,
517 static struct dma_buf *vb2_dma_sg_get_dmabuf(void *buf_priv, unsigned long flags)
519 struct vb2_dma_sg_buf *buf = buf_priv;
520 struct dma_buf *dbuf;
521 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
523 exp_info.ops = &vb2_dma_sg_dmabuf_ops;
524 exp_info.size = buf->size;
525 exp_info.flags = flags;
528 if (WARN_ON(!buf->dma_sgt))
531 dbuf = dma_buf_export(&exp_info);
535 /* dmabuf keeps reference to vb2 buffer */
536 refcount_inc(&buf->refcount);
541 /*********************************************/
542 /* callbacks for DMABUF buffers */
543 /*********************************************/
545 static int vb2_dma_sg_map_dmabuf(void *mem_priv)
547 struct vb2_dma_sg_buf *buf = mem_priv;
548 struct sg_table *sgt;
550 if (WARN_ON(!buf->db_attach)) {
551 pr_err("trying to pin a non attached buffer\n");
555 if (WARN_ON(buf->dma_sgt)) {
556 pr_err("dmabuf buffer is already pinned\n");
560 /* get the associated scatterlist for this buffer */
561 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
563 pr_err("Error getting dmabuf scatterlist\n");
573 static void vb2_dma_sg_unmap_dmabuf(void *mem_priv)
575 struct vb2_dma_sg_buf *buf = mem_priv;
576 struct sg_table *sgt = buf->dma_sgt;
578 if (WARN_ON(!buf->db_attach)) {
579 pr_err("trying to unpin a not attached buffer\n");
584 pr_err("dmabuf buffer is already unpinned\n");
589 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
592 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
597 static void vb2_dma_sg_detach_dmabuf(void *mem_priv)
599 struct vb2_dma_sg_buf *buf = mem_priv;
601 /* if vb2 works correctly you should never detach mapped buffer */
602 if (WARN_ON(buf->dma_sgt))
603 vb2_dma_sg_unmap_dmabuf(buf);
605 /* detach this attachment */
606 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
610 static void *vb2_dma_sg_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
611 unsigned long size, enum dma_data_direction dma_dir)
613 struct vb2_dma_sg_buf *buf;
614 struct dma_buf_attachment *dba;
617 return ERR_PTR(-EINVAL);
619 if (dbuf->size < size)
620 return ERR_PTR(-EFAULT);
622 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
624 return ERR_PTR(-ENOMEM);
627 /* create attachment for the dmabuf with the user device */
628 dba = dma_buf_attach(dbuf, buf->dev);
630 pr_err("failed to attach dmabuf\n");
635 buf->dma_dir = dma_dir;
637 buf->db_attach = dba;
642 static void *vb2_dma_sg_cookie(void *buf_priv)
644 struct vb2_dma_sg_buf *buf = buf_priv;
649 const struct vb2_mem_ops vb2_dma_sg_memops = {
650 .alloc = vb2_dma_sg_alloc,
651 .put = vb2_dma_sg_put,
652 .get_userptr = vb2_dma_sg_get_userptr,
653 .put_userptr = vb2_dma_sg_put_userptr,
654 .prepare = vb2_dma_sg_prepare,
655 .finish = vb2_dma_sg_finish,
656 .vaddr = vb2_dma_sg_vaddr,
657 .mmap = vb2_dma_sg_mmap,
658 .num_users = vb2_dma_sg_num_users,
659 .get_dmabuf = vb2_dma_sg_get_dmabuf,
660 .map_dmabuf = vb2_dma_sg_map_dmabuf,
661 .unmap_dmabuf = vb2_dma_sg_unmap_dmabuf,
662 .attach_dmabuf = vb2_dma_sg_attach_dmabuf,
663 .detach_dmabuf = vb2_dma_sg_detach_dmabuf,
664 .cookie = vb2_dma_sg_cookie,
666 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
668 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
669 MODULE_AUTHOR("Andrzej Pietrasiewicz");
670 MODULE_LICENSE("GPL");