2 * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2
4 * Copyright (C) 2010 Samsung Electronics
6 * Author: Pawel Osciak <pawel@osciak.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/dma-buf.h>
14 #include <linux/module.h>
15 #include <linux/scatterlist.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/dma-mapping.h>
20 #include <media/videobuf2-v4l2.h>
21 #include <media/videobuf2-dma-contig.h>
22 #include <media/videobuf2-memops.h>
31 enum dma_data_direction dma_dir;
32 struct sg_table *dma_sgt;
33 struct frame_vector *vec;
36 struct vb2_vmarea_handler handler;
38 struct sg_table *sgt_base;
41 struct dma_buf_attachment *db_attach;
44 /*********************************************/
45 /* scatterlist table functions */
46 /*********************************************/
48 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
50 struct scatterlist *s;
51 dma_addr_t expected = sg_dma_address(sgt->sgl);
53 unsigned long size = 0;
55 for_each_sg(sgt->sgl, s, sgt->nents, i) {
56 if (sg_dma_address(s) != expected)
58 expected = sg_dma_address(s) + sg_dma_len(s);
59 size += sg_dma_len(s);
64 /*********************************************/
65 /* callbacks for all buffers */
66 /*********************************************/
68 static void *vb2_dc_cookie(void *buf_priv)
70 struct vb2_dc_buf *buf = buf_priv;
72 return &buf->dma_addr;
75 static void *vb2_dc_vaddr(void *buf_priv)
77 struct vb2_dc_buf *buf = buf_priv;
79 if (!buf->vaddr && buf->db_attach)
80 buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf);
85 static unsigned int vb2_dc_num_users(void *buf_priv)
87 struct vb2_dc_buf *buf = buf_priv;
89 return atomic_read(&buf->refcount);
92 static void vb2_dc_prepare(void *buf_priv)
94 struct vb2_dc_buf *buf = buf_priv;
95 struct sg_table *sgt = buf->dma_sgt;
97 /* DMABUF exporter will flush the cache for us */
98 if (!sgt || buf->db_attach)
101 dma_sync_sg_for_device(buf->dev, sgt->sgl, sgt->orig_nents,
105 static void vb2_dc_finish(void *buf_priv)
107 struct vb2_dc_buf *buf = buf_priv;
108 struct sg_table *sgt = buf->dma_sgt;
110 /* DMABUF exporter will flush the cache for us */
111 if (!sgt || buf->db_attach)
114 dma_sync_sg_for_cpu(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir);
117 /*********************************************/
118 /* callbacks for MMAP buffers */
119 /*********************************************/
121 static void vb2_dc_put(void *buf_priv)
123 struct vb2_dc_buf *buf = buf_priv;
125 if (!atomic_dec_and_test(&buf->refcount))
129 sg_free_table(buf->sgt_base);
130 kfree(buf->sgt_base);
132 dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
134 put_device(buf->dev);
138 static void *vb2_dc_alloc(struct device *dev, unsigned long attrs,
139 unsigned long size, enum dma_data_direction dma_dir,
142 struct vb2_dc_buf *buf;
145 return ERR_PTR(-EINVAL);
147 buf = kzalloc(sizeof *buf, GFP_KERNEL);
149 return ERR_PTR(-ENOMEM);
153 buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr,
154 GFP_KERNEL | gfp_flags, buf->attrs);
156 dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
158 return ERR_PTR(-ENOMEM);
161 if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
162 buf->vaddr = buf->cookie;
164 /* Prevent the device from being released while the buffer is used */
165 buf->dev = get_device(dev);
167 buf->dma_dir = dma_dir;
169 buf->handler.refcount = &buf->refcount;
170 buf->handler.put = vb2_dc_put;
171 buf->handler.arg = buf;
173 atomic_inc(&buf->refcount);
178 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
180 struct vb2_dc_buf *buf = buf_priv;
184 printk(KERN_ERR "No buffer to map\n");
189 * dma_mmap_* uses vm_pgoff as in-buffer offset, but we want to
194 ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
195 buf->dma_addr, buf->size, buf->attrs);
198 pr_err("Remapping memory failed, error: %d\n", ret);
202 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
203 vma->vm_private_data = &buf->handler;
204 vma->vm_ops = &vb2_common_vm_ops;
206 vma->vm_ops->open(vma);
208 pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n",
209 __func__, (unsigned long)buf->dma_addr, vma->vm_start,
215 /*********************************************/
216 /* DMABUF ops for exporters */
217 /*********************************************/
219 struct vb2_dc_attachment {
221 enum dma_data_direction dma_dir;
224 static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct device *dev,
225 struct dma_buf_attachment *dbuf_attach)
227 struct vb2_dc_attachment *attach;
229 struct scatterlist *rd, *wr;
230 struct sg_table *sgt;
231 struct vb2_dc_buf *buf = dbuf->priv;
234 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
239 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
240 * map the same scatter list to multiple attachments at the same time.
242 ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
248 rd = buf->sgt_base->sgl;
250 for (i = 0; i < sgt->orig_nents; ++i) {
251 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
256 attach->dma_dir = DMA_NONE;
257 dbuf_attach->priv = attach;
262 static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
263 struct dma_buf_attachment *db_attach)
265 struct vb2_dc_attachment *attach = db_attach->priv;
266 struct sg_table *sgt;
273 /* release the scatterlist cache */
274 if (attach->dma_dir != DMA_NONE)
275 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
279 db_attach->priv = NULL;
282 static struct sg_table *vb2_dc_dmabuf_ops_map(
283 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
285 struct vb2_dc_attachment *attach = db_attach->priv;
286 /* stealing dmabuf mutex to serialize map/unmap operations */
287 struct mutex *lock = &db_attach->dmabuf->lock;
288 struct sg_table *sgt;
293 /* return previously mapped sg table */
294 if (attach->dma_dir == dma_dir) {
299 /* release any previous cache */
300 if (attach->dma_dir != DMA_NONE) {
301 dma_unmap_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
303 attach->dma_dir = DMA_NONE;
306 /* mapping to the client with new direction */
307 sgt->nents = dma_map_sg(db_attach->dev, sgt->sgl, sgt->orig_nents,
310 pr_err("failed to map scatterlist\n");
312 return ERR_PTR(-EIO);
315 attach->dma_dir = dma_dir;
322 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
323 struct sg_table *sgt, enum dma_data_direction dma_dir)
325 /* nothing to be done here */
328 static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
330 /* drop reference obtained in vb2_dc_get_dmabuf */
331 vb2_dc_put(dbuf->priv);
334 static void *vb2_dc_dmabuf_ops_kmap(struct dma_buf *dbuf, unsigned long pgnum)
336 struct vb2_dc_buf *buf = dbuf->priv;
338 return buf->vaddr ? buf->vaddr + pgnum * PAGE_SIZE : NULL;
341 static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf)
343 struct vb2_dc_buf *buf = dbuf->priv;
348 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
349 struct vm_area_struct *vma)
351 return vb2_dc_mmap(dbuf->priv, vma);
354 static struct dma_buf_ops vb2_dc_dmabuf_ops = {
355 .attach = vb2_dc_dmabuf_ops_attach,
356 .detach = vb2_dc_dmabuf_ops_detach,
357 .map_dma_buf = vb2_dc_dmabuf_ops_map,
358 .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
359 .kmap = vb2_dc_dmabuf_ops_kmap,
360 .kmap_atomic = vb2_dc_dmabuf_ops_kmap,
361 .vmap = vb2_dc_dmabuf_ops_vmap,
362 .mmap = vb2_dc_dmabuf_ops_mmap,
363 .release = vb2_dc_dmabuf_ops_release,
366 static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
369 struct sg_table *sgt;
371 sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
373 dev_err(buf->dev, "failed to alloc sg table\n");
377 ret = dma_get_sgtable_attrs(buf->dev, sgt, buf->cookie, buf->dma_addr,
378 buf->size, buf->attrs);
380 dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
388 static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags)
390 struct vb2_dc_buf *buf = buf_priv;
391 struct dma_buf *dbuf;
392 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
394 exp_info.ops = &vb2_dc_dmabuf_ops;
395 exp_info.size = buf->size;
396 exp_info.flags = flags;
400 buf->sgt_base = vb2_dc_get_base_sgt(buf);
402 if (WARN_ON(!buf->sgt_base))
405 dbuf = dma_buf_export(&exp_info);
409 /* dmabuf keeps reference to vb2 buffer */
410 atomic_inc(&buf->refcount);
415 /*********************************************/
416 /* callbacks for USERPTR buffers */
417 /*********************************************/
419 static void vb2_dc_put_userptr(void *buf_priv)
421 struct vb2_dc_buf *buf = buf_priv;
422 struct sg_table *sgt = buf->dma_sgt;
428 * No need to sync to CPU, it's already synced to the CPU
429 * since the finish() memop will have been called before this.
431 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
432 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
433 pages = frame_vector_pages(buf->vec);
434 /* sgt should exist only if vector contains pages... */
435 BUG_ON(IS_ERR(pages));
436 for (i = 0; i < frame_vector_count(buf->vec); i++)
437 set_page_dirty_lock(pages[i]);
441 vb2_destroy_framevec(buf->vec);
446 * For some kind of reserved memory there might be no struct page available,
447 * so all that can be done to support such 'pages' is to try to convert
448 * pfn to dma address or at the last resort just assume that
449 * dma address == physical address (like it has been assumed in earlier version
450 * of videobuf2-dma-contig
453 #ifdef __arch_pfn_to_dma
454 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
456 return (dma_addr_t)__arch_pfn_to_dma(dev, pfn);
458 #elif defined(__pfn_to_bus)
459 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
461 return (dma_addr_t)__pfn_to_bus(pfn);
463 #elif defined(__pfn_to_phys)
464 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
466 return (dma_addr_t)__pfn_to_phys(pfn);
469 static inline dma_addr_t vb2_dc_pfn_to_dma(struct device *dev, unsigned long pfn)
471 /* really, we cannot do anything better at this point */
472 return (dma_addr_t)(pfn) << PAGE_SHIFT;
476 static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
477 unsigned long size, enum dma_data_direction dma_dir)
479 struct vb2_dc_buf *buf;
480 struct frame_vector *vec;
481 unsigned long offset;
484 struct sg_table *sgt;
485 unsigned long contig_size;
486 unsigned long dma_align = dma_get_cache_alignment();
488 /* Only cache aligned DMA transfers are reliable */
489 if (!IS_ALIGNED(vaddr | size, dma_align)) {
490 pr_debug("user data must be aligned to %lu bytes\n", dma_align);
491 return ERR_PTR(-EINVAL);
495 pr_debug("size is zero\n");
496 return ERR_PTR(-EINVAL);
500 return ERR_PTR(-EINVAL);
502 buf = kzalloc(sizeof *buf, GFP_KERNEL);
504 return ERR_PTR(-ENOMEM);
507 buf->dma_dir = dma_dir;
509 offset = vaddr & ~PAGE_MASK;
510 vec = vb2_create_framevec(vaddr, size, dma_dir == DMA_FROM_DEVICE);
516 n_pages = frame_vector_count(vec);
517 ret = frame_vector_to_pages(vec);
519 unsigned long *nums = frame_vector_pfns(vec);
522 * Failed to convert to pages... Check the memory is physically
523 * contiguous and use direct mapping
525 for (i = 1; i < n_pages; i++)
526 if (nums[i-1] + 1 != nums[i])
528 buf->dma_addr = vb2_dc_pfn_to_dma(buf->dev, nums[0]);
532 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
534 pr_err("failed to allocate sg table\n");
539 ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages,
540 offset, size, GFP_KERNEL);
542 pr_err("failed to initialize sg table\n");
547 * No need to sync to the device, this will happen later when the
548 * prepare() memop is called.
550 sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
551 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
552 if (sgt->nents <= 0) {
553 pr_err("failed to map scatterlist\n");
558 contig_size = vb2_dc_get_contiguous_size(sgt);
559 if (contig_size < size) {
560 pr_err("contiguous mapping is too small %lu/%lu\n",
566 buf->dma_addr = sg_dma_address(sgt->sgl);
574 dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
575 buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
584 vb2_destroy_framevec(vec);
592 /*********************************************/
593 /* callbacks for DMABUF buffers */
594 /*********************************************/
596 static int vb2_dc_map_dmabuf(void *mem_priv)
598 struct vb2_dc_buf *buf = mem_priv;
599 struct sg_table *sgt;
600 unsigned long contig_size;
602 if (WARN_ON(!buf->db_attach)) {
603 pr_err("trying to pin a non attached buffer\n");
607 if (WARN_ON(buf->dma_sgt)) {
608 pr_err("dmabuf buffer is already pinned\n");
612 /* get the associated scatterlist for this buffer */
613 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
615 pr_err("Error getting dmabuf scatterlist\n");
619 /* checking if dmabuf is big enough to store contiguous chunk */
620 contig_size = vb2_dc_get_contiguous_size(sgt);
621 if (contig_size < buf->size) {
622 pr_err("contiguous chunk is too small %lu/%lu b\n",
623 contig_size, buf->size);
624 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
628 buf->dma_addr = sg_dma_address(sgt->sgl);
635 static void vb2_dc_unmap_dmabuf(void *mem_priv)
637 struct vb2_dc_buf *buf = mem_priv;
638 struct sg_table *sgt = buf->dma_sgt;
640 if (WARN_ON(!buf->db_attach)) {
641 pr_err("trying to unpin a not attached buffer\n");
646 pr_err("dmabuf buffer is already unpinned\n");
651 dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr);
654 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
660 static void vb2_dc_detach_dmabuf(void *mem_priv)
662 struct vb2_dc_buf *buf = mem_priv;
664 /* if vb2 works correctly you should never detach mapped buffer */
665 if (WARN_ON(buf->dma_addr))
666 vb2_dc_unmap_dmabuf(buf);
668 /* detach this attachment */
669 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
673 static void *vb2_dc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf,
674 unsigned long size, enum dma_data_direction dma_dir)
676 struct vb2_dc_buf *buf;
677 struct dma_buf_attachment *dba;
679 if (dbuf->size < size)
680 return ERR_PTR(-EFAULT);
683 return ERR_PTR(-EINVAL);
685 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
687 return ERR_PTR(-ENOMEM);
690 /* create attachment for the dmabuf with the user device */
691 dba = dma_buf_attach(dbuf, buf->dev);
693 pr_err("failed to attach dmabuf\n");
698 buf->dma_dir = dma_dir;
700 buf->db_attach = dba;
705 /*********************************************/
706 /* DMA CONTIG exported functions */
707 /*********************************************/
709 const struct vb2_mem_ops vb2_dma_contig_memops = {
710 .alloc = vb2_dc_alloc,
712 .get_dmabuf = vb2_dc_get_dmabuf,
713 .cookie = vb2_dc_cookie,
714 .vaddr = vb2_dc_vaddr,
716 .get_userptr = vb2_dc_get_userptr,
717 .put_userptr = vb2_dc_put_userptr,
718 .prepare = vb2_dc_prepare,
719 .finish = vb2_dc_finish,
720 .map_dmabuf = vb2_dc_map_dmabuf,
721 .unmap_dmabuf = vb2_dc_unmap_dmabuf,
722 .attach_dmabuf = vb2_dc_attach_dmabuf,
723 .detach_dmabuf = vb2_dc_detach_dmabuf,
724 .num_users = vb2_dc_num_users,
726 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
729 * vb2_dma_contig_set_max_seg_size() - configure DMA max segment size
730 * @dev: device for configuring DMA parameters
731 * @size: size of DMA max segment size to set
733 * To allow mapping the scatter-list into a single chunk in the DMA
734 * address space, the device is required to have the DMA max segment
735 * size parameter set to a value larger than the buffer size. Otherwise,
736 * the DMA-mapping subsystem will split the mapping into max segment
737 * size chunks. This function sets the DMA max segment size
738 * parameter to let DMA-mapping map a buffer as a single chunk in DMA
740 * This code assumes that the DMA-mapping subsystem will merge all
741 * scatterlist segments if this is really possible (for example when
742 * an IOMMU is available and enabled).
743 * Ideally, this parameter should be set by the generic bus code, but it
744 * is left with the default 64KiB value due to historical litmiations in
745 * other subsystems (like limited USB host drivers) and there no good
746 * place to set it to the proper value.
747 * This function should be called from the drivers, which are known to
748 * operate on platforms with IOMMU and provide access to shared buffers
749 * (either USERPTR or DMABUF). This should be done before initializing
752 int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size)
754 if (!dev->dma_parms) {
755 dev->dma_parms = kzalloc(sizeof(*dev->dma_parms), GFP_KERNEL);
759 if (dma_get_max_seg_size(dev) < size)
760 return dma_set_max_seg_size(dev, size);
764 EXPORT_SYMBOL_GPL(vb2_dma_contig_set_max_seg_size);
767 * vb2_dma_contig_clear_max_seg_size() - release resources for DMA parameters
768 * @dev: device for configuring DMA parameters
770 * This function releases resources allocated to configure DMA parameters
771 * (see vb2_dma_contig_set_max_seg_size() function). It should be called from
772 * device drivers on driver remove.
774 void vb2_dma_contig_clear_max_seg_size(struct device *dev)
776 kfree(dev->dma_parms);
777 dev->dma_parms = NULL;
779 EXPORT_SYMBOL_GPL(vb2_dma_contig_clear_max_seg_size);
781 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
782 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
783 MODULE_LICENSE("GPL");