/* * videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2 * * Copyright (C) 2010 Samsung Electronics * * Author: Pawel Osciak * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include struct vb2_dc_buf { struct device *dev; void *vaddr; unsigned long size; void *cookie; dma_addr_t dma_addr; unsigned long attrs; enum dma_data_direction dma_dir; struct sg_table *dma_sgt; struct frame_vector *vec; /* MMAP related */ struct vb2_vmarea_handler handler; refcount_t refcount; struct sg_table *sgt_base; /* DMABUF related */ struct dma_buf_attachment *db_attach; }; /*********************************************/ /* scatterlist table functions */ /*********************************************/ static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt) { struct scatterlist *s; dma_addr_t expected = sg_dma_address(sgt->sgl); unsigned int i; unsigned long size = 0; for_each_sgtable_dma_sg(sgt, s, i) { if (sg_dma_address(s) != expected) break; expected += sg_dma_len(s); size += sg_dma_len(s); } return size; } /*********************************************/ /* callbacks for all buffers */ /*********************************************/ static void *vb2_dc_cookie(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; return &buf->dma_addr; } static void *vb2_dc_vaddr(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; if (!buf->vaddr && buf->db_attach) buf->vaddr = dma_buf_vmap(buf->db_attach->dmabuf); return buf->vaddr; } static unsigned int vb2_dc_num_users(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; return refcount_read(&buf->refcount); } static void vb2_dc_prepare(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; struct sg_table *sgt = buf->dma_sgt; if (!sgt) return; dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir); } static void vb2_dc_finish(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; struct sg_table *sgt = buf->dma_sgt; if (!sgt) return; dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir); } /*********************************************/ /* callbacks for MMAP buffers */ /*********************************************/ static void vb2_dc_put(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; if (!refcount_dec_and_test(&buf->refcount)) return; if (buf->sgt_base) { sg_free_table(buf->sgt_base); kfree(buf->sgt_base); } dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr, buf->attrs); put_device(buf->dev); kfree(buf); } static void *vb2_dc_alloc(struct device *dev, unsigned long attrs, unsigned long size, enum dma_data_direction dma_dir, gfp_t gfp_flags) { struct vb2_dc_buf *buf; if (WARN_ON(!dev)) return ERR_PTR(-EINVAL); buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); buf->attrs = attrs; buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr, GFP_KERNEL | gfp_flags, buf->attrs); if (!buf->cookie) { dev_err(dev, "dma_alloc_coherent of size %lu failed\n", size); kfree(buf); return ERR_PTR(-ENOMEM); } if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0) buf->vaddr = buf->cookie; /* Prevent the device from being released while the buffer is used */ buf->dev = get_device(dev); buf->size = size; buf->dma_dir = dma_dir; buf->handler.refcount = &buf->refcount; buf->handler.put = vb2_dc_put; buf->handler.arg = buf; refcount_set(&buf->refcount, 1); return buf; } static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma) { struct vb2_dc_buf *buf = buf_priv; int ret; if (!buf) { printk(KERN_ERR "No buffer to map\n"); return -EINVAL; } ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, buf->dma_addr, buf->size, buf->attrs); if (ret) { pr_err("Remapping memory failed, error: %d\n", ret); return ret; } vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; vma->vm_private_data = &buf->handler; vma->vm_ops = &vb2_common_vm_ops; vma->vm_ops->open(vma); pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %lu\n", __func__, (unsigned long)buf->dma_addr, vma->vm_start, buf->size); return 0; } /*********************************************/ /* DMABUF ops for exporters */ /*********************************************/ struct vb2_dc_attachment { struct sg_table sgt; enum dma_data_direction dma_dir; }; static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, struct dma_buf_attachment *dbuf_attach) { struct vb2_dc_attachment *attach; unsigned int i; struct scatterlist *rd, *wr; struct sg_table *sgt; struct vb2_dc_buf *buf = dbuf->priv; int ret; attach = kzalloc(sizeof(*attach), GFP_KERNEL); if (!attach) return -ENOMEM; sgt = &attach->sgt; /* Copy the buf->base_sgt scatter list to the attachment, as we can't * map the same scatter list to multiple attachments at the same time. */ ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL); if (ret) { kfree(attach); return -ENOMEM; } rd = buf->sgt_base->sgl; wr = sgt->sgl; for (i = 0; i < sgt->orig_nents; ++i) { sg_set_page(wr, sg_page(rd), rd->length, rd->offset); rd = sg_next(rd); wr = sg_next(wr); } attach->dma_dir = DMA_NONE; dbuf_attach->priv = attach; return 0; } static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf, struct dma_buf_attachment *db_attach) { struct vb2_dc_attachment *attach = db_attach->priv; struct sg_table *sgt; if (!attach) return; sgt = &attach->sgt; /* release the scatterlist cache */ if (attach->dma_dir != DMA_NONE) /* * Cache sync can be skipped here, as the vb2_dc memory is * allocated from device coherent memory, which means the * memory locations do not require any explicit cache * maintenance prior or after being used by the device. */ dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); sg_free_table(sgt); kfree(attach); db_attach->priv = NULL; } static struct sg_table *vb2_dc_dmabuf_ops_map( struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) { struct vb2_dc_attachment *attach = db_attach->priv; /* stealing dmabuf mutex to serialize map/unmap operations */ struct mutex *lock = &db_attach->dmabuf->lock; struct sg_table *sgt; mutex_lock(lock); sgt = &attach->sgt; /* return previously mapped sg table */ if (attach->dma_dir == dma_dir) { mutex_unlock(lock); return sgt; } /* release any previous cache */ if (attach->dma_dir != DMA_NONE) { dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); attach->dma_dir = DMA_NONE; } /* * mapping to the client with new direction, no cache sync * required see comment in vb2_dc_dmabuf_ops_detach() */ if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, DMA_ATTR_SKIP_CPU_SYNC)) { pr_err("failed to map scatterlist\n"); mutex_unlock(lock); return ERR_PTR(-EIO); } attach->dma_dir = dma_dir; mutex_unlock(lock); return sgt; } static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, struct sg_table *sgt, enum dma_data_direction dma_dir) { /* nothing to be done here */ } static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf) { /* drop reference obtained in vb2_dc_get_dmabuf */ vb2_dc_put(dbuf->priv); } static int vb2_dc_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, enum dma_data_direction direction) { return 0; } static int vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, enum dma_data_direction direction) { return 0; } static void *vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf) { struct vb2_dc_buf *buf = dbuf->priv; return buf->vaddr; } static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf, struct vm_area_struct *vma) { return vb2_dc_mmap(dbuf->priv, vma); } static const struct dma_buf_ops vb2_dc_dmabuf_ops = { .attach = vb2_dc_dmabuf_ops_attach, .detach = vb2_dc_dmabuf_ops_detach, .map_dma_buf = vb2_dc_dmabuf_ops_map, .unmap_dma_buf = vb2_dc_dmabuf_ops_unmap, .begin_cpu_access = vb2_dc_dmabuf_ops_begin_cpu_access, .end_cpu_access = vb2_dc_dmabuf_ops_end_cpu_access, .vmap = vb2_dc_dmabuf_ops_vmap, .mmap = vb2_dc_dmabuf_ops_mmap, .release = vb2_dc_dmabuf_ops_release, }; static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf) { int ret; struct sg_table *sgt; sgt = kmalloc(sizeof(*sgt), GFP_KERNEL); if (!sgt) { dev_err(buf->dev, "failed to alloc sg table\n"); return NULL; } ret = dma_get_sgtable_attrs(buf->dev, sgt, buf->cookie, buf->dma_addr, buf->size, buf->attrs); if (ret < 0) { dev_err(buf->dev, "failed to get scatterlist from DMA API\n"); kfree(sgt); return NULL; } return sgt; } static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags) { struct vb2_dc_buf *buf = buf_priv; struct dma_buf *dbuf; DEFINE_DMA_BUF_EXPORT_INFO(exp_info); exp_info.ops = &vb2_dc_dmabuf_ops; exp_info.size = buf->size; exp_info.flags = flags; exp_info.priv = buf; if (!buf->sgt_base) buf->sgt_base = vb2_dc_get_base_sgt(buf); if (WARN_ON(!buf->sgt_base)) return NULL; dbuf = dma_buf_export(&exp_info); if (IS_ERR(dbuf)) return NULL; /* dmabuf keeps reference to vb2 buffer */ refcount_inc(&buf->refcount); return dbuf; } /*********************************************/ /* callbacks for USERPTR buffers */ /*********************************************/ static void vb2_dc_put_userptr(void *buf_priv) { struct vb2_dc_buf *buf = buf_priv; struct sg_table *sgt = buf->dma_sgt; int i; struct page **pages; if (sgt) { /* * No need to sync to CPU, it's already synced to the CPU * since the finish() memop will have been called before this. */ dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); pages = frame_vector_pages(buf->vec); /* sgt should exist only if vector contains pages... */ BUG_ON(IS_ERR(pages)); if (buf->dma_dir == DMA_FROM_DEVICE || buf->dma_dir == DMA_BIDIRECTIONAL) for (i = 0; i < frame_vector_count(buf->vec); i++) set_page_dirty_lock(pages[i]); sg_free_table(sgt); kfree(sgt); } else { dma_unmap_resource(buf->dev, buf->dma_addr, buf->size, buf->dma_dir, 0); } vb2_destroy_framevec(buf->vec); kfree(buf); } static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr, unsigned long size, enum dma_data_direction dma_dir) { struct vb2_dc_buf *buf; struct frame_vector *vec; unsigned int offset; int n_pages, i; int ret = 0; struct sg_table *sgt; unsigned long contig_size; unsigned long dma_align = dma_get_cache_alignment(); /* Only cache aligned DMA transfers are reliable */ if (!IS_ALIGNED(vaddr | size, dma_align)) { pr_debug("user data must be aligned to %lu bytes\n", dma_align); return ERR_PTR(-EINVAL); } if (!size) { pr_debug("size is zero\n"); return ERR_PTR(-EINVAL); } if (WARN_ON(!dev)) return ERR_PTR(-EINVAL); buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); buf->dev = dev; buf->dma_dir = dma_dir; offset = lower_32_bits(offset_in_page(vaddr)); vec = vb2_create_framevec(vaddr, size); if (IS_ERR(vec)) { ret = PTR_ERR(vec); goto fail_buf; } buf->vec = vec; n_pages = frame_vector_count(vec); ret = frame_vector_to_pages(vec); if (ret < 0) { unsigned long *nums = frame_vector_pfns(vec); /* * Failed to convert to pages... Check the memory is physically * contiguous and use direct mapping */ for (i = 1; i < n_pages; i++) if (nums[i-1] + 1 != nums[i]) goto fail_pfnvec; buf->dma_addr = dma_map_resource(buf->dev, __pfn_to_phys(nums[0]), size, buf->dma_dir, 0); if (dma_mapping_error(buf->dev, buf->dma_addr)) { ret = -ENOMEM; goto fail_pfnvec; } goto out; } sgt = kzalloc(sizeof(*sgt), GFP_KERNEL); if (!sgt) { pr_err("failed to allocate sg table\n"); ret = -ENOMEM; goto fail_pfnvec; } ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages, offset, size, GFP_KERNEL); if (ret) { pr_err("failed to initialize sg table\n"); goto fail_sgt; } /* * No need to sync to the device, this will happen later when the * prepare() memop is called. */ if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC)) { pr_err("failed to map scatterlist\n"); ret = -EIO; goto fail_sgt_init; } contig_size = vb2_dc_get_contiguous_size(sgt); if (contig_size < size) { pr_err("contiguous mapping is too small %lu/%lu\n", contig_size, size); ret = -EFAULT; goto fail_map_sg; } buf->dma_addr = sg_dma_address(sgt->sgl); buf->dma_sgt = sgt; out: buf->size = size; return buf; fail_map_sg: dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); fail_sgt_init: sg_free_table(sgt); fail_sgt: kfree(sgt); fail_pfnvec: vb2_destroy_framevec(vec); fail_buf: kfree(buf); return ERR_PTR(ret); } /*********************************************/ /* callbacks for DMABUF buffers */ /*********************************************/ static int vb2_dc_map_dmabuf(void *mem_priv) { struct vb2_dc_buf *buf = mem_priv; struct sg_table *sgt; unsigned long contig_size; if (WARN_ON(!buf->db_attach)) { pr_err("trying to pin a non attached buffer\n"); return -EINVAL; } if (WARN_ON(buf->dma_sgt)) { pr_err("dmabuf buffer is already pinned\n"); return 0; } /* get the associated scatterlist for this buffer */ sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir); if (IS_ERR(sgt)) { pr_err("Error getting dmabuf scatterlist\n"); return -EINVAL; } /* checking if dmabuf is big enough to store contiguous chunk */ contig_size = vb2_dc_get_contiguous_size(sgt); if (contig_size < buf->size) { pr_err("contiguous chunk is too small %lu/%lu\n", contig_size, buf->size); dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); return -EFAULT; } buf->dma_addr = sg_dma_address(sgt->sgl); buf->dma_sgt = sgt; buf->vaddr = NULL; return 0; } static void vb2_dc_unmap_dmabuf(void *mem_priv) { struct vb2_dc_buf *buf = mem_priv; struct sg_table *sgt = buf->dma_sgt; if (WARN_ON(!buf->db_attach)) { pr_err("trying to unpin a not attached buffer\n"); return; } if (WARN_ON(!sgt)) { pr_err("dmabuf buffer is already unpinned\n"); return; } if (buf->vaddr) { dma_buf_vunmap(buf->db_attach->dmabuf, buf->vaddr); buf->vaddr = NULL; } dma_buf_unmap_attachment(buf->db_attach, sgt, buf->dma_dir); buf->dma_addr = 0; buf->dma_sgt = NULL; } static void vb2_dc_detach_dmabuf(void *mem_priv) { struct vb2_dc_buf *buf = mem_priv; /* if vb2 works correctly you should never detach mapped buffer */ if (WARN_ON(buf->dma_addr)) vb2_dc_unmap_dmabuf(buf); /* detach this attachment */ dma_buf_detach(buf->db_attach->dmabuf, buf->db_attach); kfree(buf); } static void *vb2_dc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf, unsigned long size, enum dma_data_direction dma_dir) { struct vb2_dc_buf *buf; struct dma_buf_attachment *dba; if (dbuf->size < size) return ERR_PTR(-EFAULT); if (WARN_ON(!dev)) return ERR_PTR(-EINVAL); buf = kzalloc(sizeof(*buf), GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); buf->dev = dev; /* create attachment for the dmabuf with the user device */ dba = dma_buf_attach(dbuf, buf->dev); if (IS_ERR(dba)) { pr_err("failed to attach dmabuf\n"); kfree(buf); return dba; } buf->dma_dir = dma_dir; buf->size = size; buf->db_attach = dba; return buf; } /*********************************************/ /* DMA CONTIG exported functions */ /*********************************************/ const struct vb2_mem_ops vb2_dma_contig_memops = { .alloc = vb2_dc_alloc, .put = vb2_dc_put, .get_dmabuf = vb2_dc_get_dmabuf, .cookie = vb2_dc_cookie, .vaddr = vb2_dc_vaddr, .mmap = vb2_dc_mmap, .get_userptr = vb2_dc_get_userptr, .put_userptr = vb2_dc_put_userptr, .prepare = vb2_dc_prepare, .finish = vb2_dc_finish, .map_dmabuf = vb2_dc_map_dmabuf, .unmap_dmabuf = vb2_dc_unmap_dmabuf, .attach_dmabuf = vb2_dc_attach_dmabuf, .detach_dmabuf = vb2_dc_detach_dmabuf, .num_users = vb2_dc_num_users, }; EXPORT_SYMBOL_GPL(vb2_dma_contig_memops); /** * vb2_dma_contig_set_max_seg_size() - configure DMA max segment size * @dev: device for configuring DMA parameters * @size: size of DMA max segment size to set * * To allow mapping the scatter-list into a single chunk in the DMA * address space, the device is required to have the DMA max segment * size parameter set to a value larger than the buffer size. Otherwise, * the DMA-mapping subsystem will split the mapping into max segment * size chunks. This function sets the DMA max segment size * parameter to let DMA-mapping map a buffer as a single chunk in DMA * address space. * This code assumes that the DMA-mapping subsystem will merge all * scatterlist segments if this is really possible (for example when * an IOMMU is available and enabled). * Ideally, this parameter should be set by the generic bus code, but it * is left with the default 64KiB value due to historical litmiations in * other subsystems (like limited USB host drivers) and there no good * place to set it to the proper value. * This function should be called from the drivers, which are known to * operate on platforms with IOMMU and provide access to shared buffers * (either USERPTR or DMABUF). This should be done before initializing * videobuf2 queue. */ int vb2_dma_contig_set_max_seg_size(struct device *dev, unsigned int size) { if (!dev->dma_parms) { dev_err(dev, "Failed to set max_seg_size: dma_parms is NULL\n"); return -ENODEV; } if (dma_get_max_seg_size(dev) < size) return dma_set_max_seg_size(dev, size); return 0; } EXPORT_SYMBOL_GPL(vb2_dma_contig_set_max_seg_size); MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2"); MODULE_AUTHOR("Pawel Osciak "); MODULE_LICENSE("GPL");