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/refcount.h>
16 #include <linux/scatterlist.h>
17 #include <linux/sched.h>
18 #include <linux/slab.h>
19 #include <linux/dma-mapping.h>
20 #include <linux/highmem.h>
22 #include <media/videobuf2-v4l2.h>
23 #include <media/videobuf2-dma-contig.h>
24 #include <media/videobuf2-memops.h>
33 enum dma_data_direction dma_dir;
34 struct sg_table *dma_sgt;
35 struct frame_vector *vec;
38 struct vb2_vmarea_handler handler;
40 struct sg_table *sgt_base;
43 struct dma_buf_attachment *db_attach;
45 struct vb2_buffer *vb;
46 bool non_coherent_mem;
49 /*********************************************/
50 /* scatterlist table functions */
51 /*********************************************/
53 static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt)
55 struct scatterlist *s;
56 dma_addr_t expected = sg_dma_address(sgt->sgl);
58 unsigned long size = 0;
60 for_each_sgtable_dma_sg(sgt, s, i) {
61 if (sg_dma_address(s) != expected)
63 expected += sg_dma_len(s);
64 size += sg_dma_len(s);
69 /*********************************************/
70 /* callbacks for all buffers */
71 /*********************************************/
73 static void *vb2_dc_cookie(struct vb2_buffer *vb, void *buf_priv)
75 struct vb2_dc_buf *buf = buf_priv;
77 return &buf->dma_addr;
81 * This function may fail if:
83 * - dma_buf_vmap() fails
84 * E.g. due to lack of virtual mapping address space, or due to
85 * dmabuf->ops misconfiguration.
87 * - dma_vmap_noncontiguous() fails
88 * For instance, when requested buffer size is larger than totalram_pages().
89 * Relevant for buffers that use non-coherent memory.
91 * - Queue DMA attrs have DMA_ATTR_NO_KERNEL_MAPPING set
92 * Relevant for buffers that use coherent memory.
94 static void *vb2_dc_vaddr(struct vb2_buffer *vb, void *buf_priv)
96 struct vb2_dc_buf *buf = buf_priv;
101 if (buf->db_attach) {
102 struct iosys_map map;
104 if (!dma_buf_vmap(buf->db_attach->dmabuf, &map))
105 buf->vaddr = map.vaddr;
110 if (buf->non_coherent_mem)
111 buf->vaddr = dma_vmap_noncontiguous(buf->dev, buf->size,
116 static unsigned int vb2_dc_num_users(void *buf_priv)
118 struct vb2_dc_buf *buf = buf_priv;
120 return refcount_read(&buf->refcount);
123 static void vb2_dc_prepare(void *buf_priv)
125 struct vb2_dc_buf *buf = buf_priv;
126 struct sg_table *sgt = buf->dma_sgt;
128 /* This takes care of DMABUF and user-enforced cache sync hint */
129 if (buf->vb->skip_cache_sync_on_prepare)
132 if (!buf->non_coherent_mem)
135 /* For both USERPTR and non-coherent MMAP */
136 dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir);
138 /* Non-coherent MMAP only */
140 flush_kernel_vmap_range(buf->vaddr, buf->size);
143 static void vb2_dc_finish(void *buf_priv)
145 struct vb2_dc_buf *buf = buf_priv;
146 struct sg_table *sgt = buf->dma_sgt;
148 /* This takes care of DMABUF and user-enforced cache sync hint */
149 if (buf->vb->skip_cache_sync_on_finish)
152 if (!buf->non_coherent_mem)
155 /* For both USERPTR and non-coherent MMAP */
156 dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir);
158 /* Non-coherent MMAP only */
160 invalidate_kernel_vmap_range(buf->vaddr, buf->size);
163 /*********************************************/
164 /* callbacks for MMAP buffers */
165 /*********************************************/
167 static void vb2_dc_put(void *buf_priv)
169 struct vb2_dc_buf *buf = buf_priv;
171 if (!refcount_dec_and_test(&buf->refcount))
174 if (buf->non_coherent_mem) {
176 dma_vunmap_noncontiguous(buf->dev, buf->vaddr);
177 dma_free_noncontiguous(buf->dev, buf->size,
178 buf->dma_sgt, buf->dma_dir);
181 sg_free_table(buf->sgt_base);
182 kfree(buf->sgt_base);
184 dma_free_attrs(buf->dev, buf->size, buf->cookie,
185 buf->dma_addr, buf->attrs);
187 put_device(buf->dev);
191 static int vb2_dc_alloc_coherent(struct vb2_dc_buf *buf)
193 struct vb2_queue *q = buf->vb->vb2_queue;
195 buf->cookie = dma_alloc_attrs(buf->dev,
198 GFP_KERNEL | q->gfp_flags,
203 if (q->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
206 buf->vaddr = buf->cookie;
210 static int vb2_dc_alloc_non_coherent(struct vb2_dc_buf *buf)
212 struct vb2_queue *q = buf->vb->vb2_queue;
214 buf->dma_sgt = dma_alloc_noncontiguous(buf->dev,
217 GFP_KERNEL | q->gfp_flags,
222 buf->dma_addr = sg_dma_address(buf->dma_sgt->sgl);
225 * For non-coherent buffers the kernel mapping is created on demand
231 static void *vb2_dc_alloc(struct vb2_buffer *vb,
235 struct vb2_dc_buf *buf;
239 return ERR_PTR(-EINVAL);
241 buf = kzalloc(sizeof *buf, GFP_KERNEL);
243 return ERR_PTR(-ENOMEM);
245 buf->attrs = vb->vb2_queue->dma_attrs;
246 buf->dma_dir = vb->vb2_queue->dma_dir;
248 buf->non_coherent_mem = vb->vb2_queue->non_coherent_mem;
251 /* Prevent the device from being released while the buffer is used */
252 buf->dev = get_device(dev);
254 if (buf->non_coherent_mem)
255 ret = vb2_dc_alloc_non_coherent(buf);
257 ret = vb2_dc_alloc_coherent(buf);
260 dev_err(dev, "dma alloc of size %lu failed\n", size);
262 return ERR_PTR(-ENOMEM);
265 buf->handler.refcount = &buf->refcount;
266 buf->handler.put = vb2_dc_put;
267 buf->handler.arg = buf;
269 refcount_set(&buf->refcount, 1);
274 static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
276 struct vb2_dc_buf *buf = buf_priv;
280 printk(KERN_ERR "No buffer to map\n");
284 if (buf->non_coherent_mem)
285 ret = dma_mmap_noncontiguous(buf->dev, vma, buf->size,
288 ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr,
289 buf->size, buf->attrs);
291 pr_err("Remapping memory failed, error: %d\n", ret);
295 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
296 vma->vm_private_data = &buf->handler;
297 vma->vm_ops = &vb2_common_vm_ops;
299 vma->vm_ops->open(vma);
301 pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %lu\n",
302 __func__, (unsigned long)buf->dma_addr, vma->vm_start,
308 /*********************************************/
309 /* DMABUF ops for exporters */
310 /*********************************************/
312 struct vb2_dc_attachment {
314 enum dma_data_direction dma_dir;
317 static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf,
318 struct dma_buf_attachment *dbuf_attach)
320 struct vb2_dc_attachment *attach;
322 struct scatterlist *rd, *wr;
323 struct sg_table *sgt;
324 struct vb2_dc_buf *buf = dbuf->priv;
327 attach = kzalloc(sizeof(*attach), GFP_KERNEL);
332 /* Copy the buf->base_sgt scatter list to the attachment, as we can't
333 * map the same scatter list to multiple attachments at the same time.
335 ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL);
341 rd = buf->sgt_base->sgl;
343 for (i = 0; i < sgt->orig_nents; ++i) {
344 sg_set_page(wr, sg_page(rd), rd->length, rd->offset);
349 attach->dma_dir = DMA_NONE;
350 dbuf_attach->priv = attach;
355 static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf,
356 struct dma_buf_attachment *db_attach)
358 struct vb2_dc_attachment *attach = db_attach->priv;
359 struct sg_table *sgt;
366 /* release the scatterlist cache */
367 if (attach->dma_dir != DMA_NONE)
369 * Cache sync can be skipped here, as the vb2_dc memory is
370 * allocated from device coherent memory, which means the
371 * memory locations do not require any explicit cache
372 * maintenance prior or after being used by the device.
374 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir,
375 DMA_ATTR_SKIP_CPU_SYNC);
378 db_attach->priv = NULL;
381 static struct sg_table *vb2_dc_dmabuf_ops_map(
382 struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir)
384 struct vb2_dc_attachment *attach = db_attach->priv;
385 /* stealing dmabuf mutex to serialize map/unmap operations */
386 struct mutex *lock = &db_attach->dmabuf->lock;
387 struct sg_table *sgt;
392 /* return previously mapped sg table */
393 if (attach->dma_dir == dma_dir) {
398 /* release any previous cache */
399 if (attach->dma_dir != DMA_NONE) {
400 dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir,
401 DMA_ATTR_SKIP_CPU_SYNC);
402 attach->dma_dir = DMA_NONE;
406 * mapping to the client with new direction, no cache sync
407 * required see comment in vb2_dc_dmabuf_ops_detach()
409 if (dma_map_sgtable(db_attach->dev, sgt, dma_dir,
410 DMA_ATTR_SKIP_CPU_SYNC)) {
411 pr_err("failed to map scatterlist\n");
413 return ERR_PTR(-EIO);
416 attach->dma_dir = dma_dir;
423 static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach,
424 struct sg_table *sgt, enum dma_data_direction dma_dir)
426 /* nothing to be done here */
429 static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf)
431 /* drop reference obtained in vb2_dc_get_dmabuf */
432 vb2_dc_put(dbuf->priv);
436 vb2_dc_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf,
437 enum dma_data_direction direction)
443 vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf,
444 enum dma_data_direction direction)
449 static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct iosys_map *map)
451 struct vb2_dc_buf *buf;
455 vaddr = vb2_dc_vaddr(buf->vb, buf);
459 iosys_map_set_vaddr(map, vaddr);
464 static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf,
465 struct vm_area_struct *vma)
467 return vb2_dc_mmap(dbuf->priv, vma);
470 static const struct dma_buf_ops vb2_dc_dmabuf_ops = {
471 .attach = vb2_dc_dmabuf_ops_attach,
472 .detach = vb2_dc_dmabuf_ops_detach,
473 .map_dma_buf = vb2_dc_dmabuf_ops_map,
474 .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap,
475 .begin_cpu_access = vb2_dc_dmabuf_ops_begin_cpu_access,
476 .end_cpu_access = vb2_dc_dmabuf_ops_end_cpu_access,
477 .vmap = vb2_dc_dmabuf_ops_vmap,
478 .mmap = vb2_dc_dmabuf_ops_mmap,
479 .release = vb2_dc_dmabuf_ops_release,
482 static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
485 struct sg_table *sgt;
487 if (buf->non_coherent_mem)
490 sgt = kmalloc(sizeof(*sgt), GFP_KERNEL);
492 dev_err(buf->dev, "failed to alloc sg table\n");
496 ret = dma_get_sgtable_attrs(buf->dev, sgt, buf->cookie, buf->dma_addr,
497 buf->size, buf->attrs);
499 dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
507 static struct dma_buf *vb2_dc_get_dmabuf(struct vb2_buffer *vb,
511 struct vb2_dc_buf *buf = buf_priv;
512 struct dma_buf *dbuf;
513 DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
515 exp_info.ops = &vb2_dc_dmabuf_ops;
516 exp_info.size = buf->size;
517 exp_info.flags = flags;
521 buf->sgt_base = vb2_dc_get_base_sgt(buf);
523 if (WARN_ON(!buf->sgt_base))
526 dbuf = dma_buf_export(&exp_info);
530 /* dmabuf keeps reference to vb2 buffer */
531 refcount_inc(&buf->refcount);
536 /*********************************************/
537 /* callbacks for USERPTR buffers */
538 /*********************************************/
540 static void vb2_dc_put_userptr(void *buf_priv)
542 struct vb2_dc_buf *buf = buf_priv;
543 struct sg_table *sgt = buf->dma_sgt;
549 * No need to sync to CPU, it's already synced to the CPU
550 * since the finish() memop will have been called before this.
552 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir,
553 DMA_ATTR_SKIP_CPU_SYNC);
554 pages = frame_vector_pages(buf->vec);
555 /* sgt should exist only if vector contains pages... */
556 BUG_ON(IS_ERR(pages));
557 if (buf->dma_dir == DMA_FROM_DEVICE ||
558 buf->dma_dir == DMA_BIDIRECTIONAL)
559 for (i = 0; i < frame_vector_count(buf->vec); i++)
560 set_page_dirty_lock(pages[i]);
564 dma_unmap_resource(buf->dev, buf->dma_addr, buf->size,
567 vb2_destroy_framevec(buf->vec);
571 static void *vb2_dc_get_userptr(struct vb2_buffer *vb, struct device *dev,
572 unsigned long vaddr, unsigned long size)
574 struct vb2_dc_buf *buf;
575 struct frame_vector *vec;
579 struct sg_table *sgt;
580 unsigned long contig_size;
581 unsigned long dma_align = dma_get_cache_alignment();
583 /* Only cache aligned DMA transfers are reliable */
584 if (!IS_ALIGNED(vaddr | size, dma_align)) {
585 pr_debug("user data must be aligned to %lu bytes\n", dma_align);
586 return ERR_PTR(-EINVAL);
590 pr_debug("size is zero\n");
591 return ERR_PTR(-EINVAL);
595 return ERR_PTR(-EINVAL);
597 buf = kzalloc(sizeof *buf, GFP_KERNEL);
599 return ERR_PTR(-ENOMEM);
602 buf->dma_dir = vb->vb2_queue->dma_dir;
605 offset = lower_32_bits(offset_in_page(vaddr));
606 vec = vb2_create_framevec(vaddr, size);
612 n_pages = frame_vector_count(vec);
613 ret = frame_vector_to_pages(vec);
615 unsigned long *nums = frame_vector_pfns(vec);
618 * Failed to convert to pages... Check the memory is physically
619 * contiguous and use direct mapping
621 for (i = 1; i < n_pages; i++)
622 if (nums[i-1] + 1 != nums[i])
624 buf->dma_addr = dma_map_resource(buf->dev,
625 __pfn_to_phys(nums[0]), size, buf->dma_dir, 0);
626 if (dma_mapping_error(buf->dev, buf->dma_addr)) {
633 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
635 pr_err("failed to allocate sg table\n");
640 ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages,
641 offset, size, GFP_KERNEL);
643 pr_err("failed to initialize sg table\n");
648 * No need to sync to the device, this will happen later when the
649 * prepare() memop is called.
651 if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir,
652 DMA_ATTR_SKIP_CPU_SYNC)) {
653 pr_err("failed to map scatterlist\n");
658 contig_size = vb2_dc_get_contiguous_size(sgt);
659 if (contig_size < size) {
660 pr_err("contiguous mapping is too small %lu/%lu\n",
666 buf->dma_addr = sg_dma_address(sgt->sgl);
668 buf->non_coherent_mem = 1;
676 dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
685 vb2_destroy_framevec(vec);
693 /*********************************************/
694 /* callbacks for DMABUF buffers */
695 /*********************************************/
697 static int vb2_dc_map_dmabuf(void *mem_priv)
699 struct vb2_dc_buf *buf = mem_priv;
700 struct sg_table *sgt;
701 unsigned long contig_size;
703 if (WARN_ON(!buf->db_attach)) {
704 pr_err("trying to pin a non attached buffer\n");
708 if (WARN_ON(buf->dma_sgt)) {
709 pr_err("dmabuf buffer is already pinned\n");
713 /* get the associated scatterlist for this buffer */
714 sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
716 pr_err("Error getting dmabuf scatterlist\n");
720 /* checking if dmabuf is big enough to store contiguous chunk */
721 contig_size = vb2_dc_get_contiguous_size(sgt);
722 if (contig_size < buf->size) {
723 pr_err("contiguous chunk is too small %lu/%lu\n",
724 contig_size, buf->size);
725 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
729 buf->dma_addr = sg_dma_address(sgt->sgl);
736 static void vb2_dc_unmap_dmabuf(void *mem_priv)
738 struct vb2_dc_buf *buf = mem_priv;
739 struct sg_table *sgt = buf->dma_sgt;
740 struct iosys_map map = IOSYS_MAP_INIT_VADDR(buf->vaddr);
742 if (WARN_ON(!buf->db_attach)) {
743 pr_err("trying to unpin a not attached buffer\n");
748 pr_err("dmabuf buffer is already unpinned\n");
753 dma_buf_vunmap(buf->db_attach->dmabuf, &map);
756 dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir);
762 static void vb2_dc_detach_dmabuf(void *mem_priv)
764 struct vb2_dc_buf *buf = mem_priv;
766 /* if vb2 works correctly you should never detach mapped buffer */
767 if (WARN_ON(buf->dma_addr))
768 vb2_dc_unmap_dmabuf(buf);
770 /* detach this attachment */
771 dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach);
775 static void *vb2_dc_attach_dmabuf(struct vb2_buffer *vb, struct device *dev,
776 struct dma_buf *dbuf, unsigned long size)
778 struct vb2_dc_buf *buf;
779 struct dma_buf_attachment *dba;
781 if (dbuf->size < size)
782 return ERR_PTR(-EFAULT);
785 return ERR_PTR(-EINVAL);
787 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
789 return ERR_PTR(-ENOMEM);
794 /* create attachment for the dmabuf with the user device */
795 dba = dma_buf_attach(dbuf, buf->dev);
797 pr_err("failed to attach dmabuf\n");
802 buf->dma_dir = vb->vb2_queue->dma_dir;
804 buf->db_attach = dba;
809 /*********************************************/
810 /* DMA CONTIG exported functions */
811 /*********************************************/
813 const struct vb2_mem_ops vb2_dma_contig_memops = {
814 .alloc = vb2_dc_alloc,
816 .get_dmabuf = vb2_dc_get_dmabuf,
817 .cookie = vb2_dc_cookie,
818 .vaddr = vb2_dc_vaddr,
820 .get_userptr = vb2_dc_get_userptr,
821 .put_userptr = vb2_dc_put_userptr,
822 .prepare = vb2_dc_prepare,
823 .finish = vb2_dc_finish,
824 .map_dmabuf = vb2_dc_map_dmabuf,
825 .unmap_dmabuf = vb2_dc_unmap_dmabuf,
826 .attach_dmabuf = vb2_dc_attach_dmabuf,
827 .detach_dmabuf = vb2_dc_detach_dmabuf,
828 .num_users = vb2_dc_num_users,
830 EXPORT_SYMBOL_GPL(vb2_dma_contig_memops);
833 * vb2_dma_contig_set_max_seg_size() - configure DMA max segment size
834 * @dev: device for configuring DMA parameters
835 * @size: size of DMA max segment size to set
837 * To allow mapping the scatter-list into a single chunk in the DMA
838 * address space, the device is required to have the DMA max segment
839 * size parameter set to a value larger than the buffer size. Otherwise,
840 * the DMA-mapping subsystem will split the mapping into max segment
841 * size chunks. This function sets the DMA max segment size
842 * parameter to let DMA-mapping map a buffer as a single chunk in DMA
844 * This code assumes that the DMA-mapping subsystem will merge all
845 * scatterlist segments if this is really possible (for example when
846 * an IOMMU is available and enabled).
847 * Ideally, this parameter should be set by the generic bus code, but it
848 * is left with the default 64KiB value due to historical litmiations in
849 * other subsystems (like limited USB host drivers) and there no good
850 * place to set it to the proper value.
851 * This function should be called from the drivers, which are known to
852 * operate on platforms with IOMMU and provide access to shared buffers
853 * (either USERPTR or DMABUF). This should be done before initializing
856 int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size)
858 if (!dev->dma_parms) {
859 dev_err(dev, "Failed to set max_seg_size: dma_parms is NULL\n");
862 if (dma_get_max_seg_size(dev) < size)
863 return dma_set_max_seg_size(dev, size);
867 EXPORT_SYMBOL_GPL(vb2_dma_contig_set_max_seg_size);
869 MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2");
870 MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
871 MODULE_LICENSE("GPL");
872 MODULE_IMPORT_NS(DMA_BUF);