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757 lines
18 KiB
757 lines
18 KiB
/* |
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* videobuf2-dma-contig.c - DMA contig memory allocator for videobuf2 |
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* |
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* Copyright (C) 2010 Samsung Electronics |
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* |
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* Author: Pawel Osciak <[email protected]> |
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* |
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* This program is free software; you can redistribute it and/or modify |
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* it under the terms of the GNU General Public License as published by |
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* the Free Software Foundation. |
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*/ |
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|
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#include <linux/dma-buf.h> |
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#include <linux/module.h> |
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#include <linux/refcount.h> |
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#include <linux/scatterlist.h> |
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#include <linux/sched.h> |
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#include <linux/slab.h> |
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#include <linux/dma-mapping.h> |
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#include <media/videobuf2-v4l2.h> |
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#include <media/videobuf2-dma-contig.h> |
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#include <media/videobuf2-memops.h> |
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|
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struct vb2_dc_buf { |
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struct device *dev; |
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void *vaddr; |
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unsigned long size; |
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void *cookie; |
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dma_addr_t dma_addr; |
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unsigned long attrs; |
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enum dma_data_direction dma_dir; |
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struct sg_table *dma_sgt; |
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struct frame_vector *vec; |
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|
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/* MMAP related */ |
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struct vb2_vmarea_handler handler; |
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refcount_t refcount; |
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struct sg_table *sgt_base; |
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|
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/* DMABUF related */ |
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struct dma_buf_attachment *db_attach; |
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}; |
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|
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/*********************************************/ |
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/* scatterlist table functions */ |
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/*********************************************/ |
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|
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static unsigned long vb2_dc_get_contiguous_size(struct sg_table *sgt) |
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{ |
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struct scatterlist *s; |
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dma_addr_t expected = sg_dma_address(sgt->sgl); |
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unsigned int i; |
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unsigned long size = 0; |
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|
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for_each_sgtable_dma_sg(sgt, s, i) { |
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if (sg_dma_address(s) != expected) |
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break; |
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expected += sg_dma_len(s); |
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size += sg_dma_len(s); |
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} |
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return size; |
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} |
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|
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/*********************************************/ |
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/* callbacks for all buffers */ |
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/*********************************************/ |
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|
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static void *vb2_dc_cookie(void *buf_priv) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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|
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return &buf->dma_addr; |
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} |
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static void *vb2_dc_vaddr(void *buf_priv) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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struct dma_buf_map map; |
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int ret; |
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|
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if (!buf->vaddr && buf->db_attach) { |
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ret = dma_buf_vmap(buf->db_attach->dmabuf, &map); |
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buf->vaddr = ret ? NULL : map.vaddr; |
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} |
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return buf->vaddr; |
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} |
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static unsigned int vb2_dc_num_users(void *buf_priv) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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|
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return refcount_read(&buf->refcount); |
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} |
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|
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static void vb2_dc_prepare(void *buf_priv) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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struct sg_table *sgt = buf->dma_sgt; |
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|
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if (!sgt) |
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return; |
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dma_sync_sgtable_for_device(buf->dev, sgt, buf->dma_dir); |
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} |
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static void vb2_dc_finish(void *buf_priv) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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struct sg_table *sgt = buf->dma_sgt; |
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|
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if (!sgt) |
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return; |
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dma_sync_sgtable_for_cpu(buf->dev, sgt, buf->dma_dir); |
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} |
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/*********************************************/ |
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/* callbacks for MMAP buffers */ |
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/*********************************************/ |
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static void vb2_dc_put(void *buf_priv) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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if (!refcount_dec_and_test(&buf->refcount)) |
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return; |
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if (buf->sgt_base) { |
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sg_free_table(buf->sgt_base); |
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kfree(buf->sgt_base); |
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} |
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dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr, |
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buf->attrs); |
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put_device(buf->dev); |
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kfree(buf); |
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} |
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static void *vb2_dc_alloc(struct device *dev, unsigned long attrs, |
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unsigned long size, enum dma_data_direction dma_dir, |
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gfp_t gfp_flags) |
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{ |
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struct vb2_dc_buf *buf; |
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if (WARN_ON(!dev)) |
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return ERR_PTR(-EINVAL); |
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buf = kzalloc(sizeof *buf, GFP_KERNEL); |
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if (!buf) |
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return ERR_PTR(-ENOMEM); |
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buf->attrs = attrs; |
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buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr, |
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GFP_KERNEL | gfp_flags, buf->attrs); |
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if (!buf->cookie) { |
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dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size); |
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kfree(buf); |
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return ERR_PTR(-ENOMEM); |
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} |
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if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0) |
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buf->vaddr = buf->cookie; |
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/* Prevent the device from being released while the buffer is used */ |
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buf->dev = get_device(dev); |
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buf->size = size; |
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buf->dma_dir = dma_dir; |
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buf->handler.refcount = &buf->refcount; |
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buf->handler.put = vb2_dc_put; |
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buf->handler.arg = buf; |
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refcount_set(&buf->refcount, 1); |
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return buf; |
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} |
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static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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int ret; |
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if (!buf) { |
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printk(KERN_ERR "No buffer to map\n"); |
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return -EINVAL; |
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} |
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ret = dma_mmap_attrs(buf->dev, vma, buf->cookie, |
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buf->dma_addr, buf->size, buf->attrs); |
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if (ret) { |
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pr_err("Remapping memory failed, error: %d\n", ret); |
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return ret; |
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} |
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vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; |
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vma->vm_private_data = &buf->handler; |
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vma->vm_ops = &vb2_common_vm_ops; |
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vma->vm_ops->open(vma); |
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pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n", |
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__func__, (unsigned long)buf->dma_addr, vma->vm_start, |
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buf->size); |
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return 0; |
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} |
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/*********************************************/ |
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/* DMABUF ops for exporters */ |
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/*********************************************/ |
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struct vb2_dc_attachment { |
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struct sg_table sgt; |
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enum dma_data_direction dma_dir; |
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}; |
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static int vb2_dc_dmabuf_ops_attach(struct dma_buf *dbuf, |
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struct dma_buf_attachment *dbuf_attach) |
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{ |
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struct vb2_dc_attachment *attach; |
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unsigned int i; |
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struct scatterlist *rd, *wr; |
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struct sg_table *sgt; |
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struct vb2_dc_buf *buf = dbuf->priv; |
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int ret; |
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attach = kzalloc(sizeof(*attach), GFP_KERNEL); |
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if (!attach) |
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return -ENOMEM; |
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sgt = &attach->sgt; |
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/* Copy the buf->base_sgt scatter list to the attachment, as we can't |
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* map the same scatter list to multiple attachments at the same time. |
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*/ |
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ret = sg_alloc_table(sgt, buf->sgt_base->orig_nents, GFP_KERNEL); |
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if (ret) { |
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kfree(attach); |
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return -ENOMEM; |
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} |
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rd = buf->sgt_base->sgl; |
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wr = sgt->sgl; |
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for (i = 0; i < sgt->orig_nents; ++i) { |
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sg_set_page(wr, sg_page(rd), rd->length, rd->offset); |
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rd = sg_next(rd); |
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wr = sg_next(wr); |
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} |
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attach->dma_dir = DMA_NONE; |
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dbuf_attach->priv = attach; |
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return 0; |
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} |
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static void vb2_dc_dmabuf_ops_detach(struct dma_buf *dbuf, |
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struct dma_buf_attachment *db_attach) |
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{ |
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struct vb2_dc_attachment *attach = db_attach->priv; |
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struct sg_table *sgt; |
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if (!attach) |
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return; |
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sgt = &attach->sgt; |
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/* release the scatterlist cache */ |
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if (attach->dma_dir != DMA_NONE) |
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/* |
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* Cache sync can be skipped here, as the vb2_dc memory is |
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* allocated from device coherent memory, which means the |
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* memory locations do not require any explicit cache |
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* maintenance prior or after being used by the device. |
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*/ |
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dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, |
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DMA_ATTR_SKIP_CPU_SYNC); |
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sg_free_table(sgt); |
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kfree(attach); |
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db_attach->priv = NULL; |
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} |
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static struct sg_table *vb2_dc_dmabuf_ops_map( |
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struct dma_buf_attachment *db_attach, enum dma_data_direction dma_dir) |
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{ |
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struct vb2_dc_attachment *attach = db_attach->priv; |
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/* stealing dmabuf mutex to serialize map/unmap operations */ |
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struct mutex *lock = &db_attach->dmabuf->lock; |
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struct sg_table *sgt; |
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mutex_lock(lock); |
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sgt = &attach->sgt; |
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/* return previously mapped sg table */ |
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if (attach->dma_dir == dma_dir) { |
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mutex_unlock(lock); |
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return sgt; |
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} |
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/* release any previous cache */ |
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if (attach->dma_dir != DMA_NONE) { |
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dma_unmap_sgtable(db_attach->dev, sgt, attach->dma_dir, |
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DMA_ATTR_SKIP_CPU_SYNC); |
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attach->dma_dir = DMA_NONE; |
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} |
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/* |
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* mapping to the client with new direction, no cache sync |
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* required see comment in vb2_dc_dmabuf_ops_detach() |
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*/ |
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if (dma_map_sgtable(db_attach->dev, sgt, dma_dir, |
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DMA_ATTR_SKIP_CPU_SYNC)) { |
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pr_err("failed to map scatterlist\n"); |
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mutex_unlock(lock); |
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return ERR_PTR(-EIO); |
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} |
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attach->dma_dir = dma_dir; |
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mutex_unlock(lock); |
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return sgt; |
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} |
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static void vb2_dc_dmabuf_ops_unmap(struct dma_buf_attachment *db_attach, |
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struct sg_table *sgt, enum dma_data_direction dma_dir) |
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{ |
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/* nothing to be done here */ |
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} |
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static void vb2_dc_dmabuf_ops_release(struct dma_buf *dbuf) |
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{ |
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/* drop reference obtained in vb2_dc_get_dmabuf */ |
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vb2_dc_put(dbuf->priv); |
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} |
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static int |
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vb2_dc_dmabuf_ops_begin_cpu_access(struct dma_buf *dbuf, |
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enum dma_data_direction direction) |
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{ |
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return 0; |
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} |
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static int |
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vb2_dc_dmabuf_ops_end_cpu_access(struct dma_buf *dbuf, |
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enum dma_data_direction direction) |
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{ |
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return 0; |
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} |
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static int vb2_dc_dmabuf_ops_vmap(struct dma_buf *dbuf, struct dma_buf_map *map) |
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{ |
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struct vb2_dc_buf *buf = dbuf->priv; |
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dma_buf_map_set_vaddr(map, buf->vaddr); |
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return 0; |
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} |
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static int vb2_dc_dmabuf_ops_mmap(struct dma_buf *dbuf, |
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struct vm_area_struct *vma) |
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{ |
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return vb2_dc_mmap(dbuf->priv, vma); |
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} |
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static const struct dma_buf_ops vb2_dc_dmabuf_ops = { |
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.attach = vb2_dc_dmabuf_ops_attach, |
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.detach = vb2_dc_dmabuf_ops_detach, |
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.map_dma_buf = vb2_dc_dmabuf_ops_map, |
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.unmap_dma_buf = vb2_dc_dmabuf_ops_unmap, |
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.begin_cpu_access = vb2_dc_dmabuf_ops_begin_cpu_access, |
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.end_cpu_access = vb2_dc_dmabuf_ops_end_cpu_access, |
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.vmap = vb2_dc_dmabuf_ops_vmap, |
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.mmap = vb2_dc_dmabuf_ops_mmap, |
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.release = vb2_dc_dmabuf_ops_release, |
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}; |
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static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf) |
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{ |
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int ret; |
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struct sg_table *sgt; |
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sgt = kmalloc(sizeof(*sgt), GFP_KERNEL); |
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if (!sgt) { |
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dev_err(buf->dev, "failed to alloc sg table\n"); |
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return NULL; |
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} |
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ret = dma_get_sgtable_attrs(buf->dev, sgt, buf->cookie, buf->dma_addr, |
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buf->size, buf->attrs); |
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if (ret < 0) { |
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dev_err(buf->dev, "failed to get scatterlist from DMA API\n"); |
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kfree(sgt); |
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return NULL; |
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} |
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return sgt; |
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} |
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static struct dma_buf *vb2_dc_get_dmabuf(void *buf_priv, unsigned long flags) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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struct dma_buf *dbuf; |
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DEFINE_DMA_BUF_EXPORT_INFO(exp_info); |
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exp_info.ops = &vb2_dc_dmabuf_ops; |
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exp_info.size = buf->size; |
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exp_info.flags = flags; |
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exp_info.priv = buf; |
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|
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if (!buf->sgt_base) |
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buf->sgt_base = vb2_dc_get_base_sgt(buf); |
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if (WARN_ON(!buf->sgt_base)) |
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return NULL; |
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dbuf = dma_buf_export(&exp_info); |
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if (IS_ERR(dbuf)) |
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return NULL; |
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|
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/* dmabuf keeps reference to vb2 buffer */ |
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refcount_inc(&buf->refcount); |
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return dbuf; |
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} |
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/*********************************************/ |
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/* callbacks for USERPTR buffers */ |
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/*********************************************/ |
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static void vb2_dc_put_userptr(void *buf_priv) |
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{ |
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struct vb2_dc_buf *buf = buf_priv; |
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struct sg_table *sgt = buf->dma_sgt; |
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int i; |
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struct page **pages; |
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|
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if (sgt) { |
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/* |
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* No need to sync to CPU, it's already synced to the CPU |
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* since the finish() memop will have been called before this. |
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*/ |
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dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, |
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DMA_ATTR_SKIP_CPU_SYNC); |
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pages = frame_vector_pages(buf->vec); |
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/* sgt should exist only if vector contains pages... */ |
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BUG_ON(IS_ERR(pages)); |
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if (buf->dma_dir == DMA_FROM_DEVICE || |
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buf->dma_dir == DMA_BIDIRECTIONAL) |
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for (i = 0; i < frame_vector_count(buf->vec); i++) |
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set_page_dirty_lock(pages[i]); |
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sg_free_table(sgt); |
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kfree(sgt); |
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} else { |
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dma_unmap_resource(buf->dev, buf->dma_addr, buf->size, |
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buf->dma_dir, 0); |
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} |
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vb2_destroy_framevec(buf->vec); |
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kfree(buf); |
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} |
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|
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static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr, |
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unsigned long size, enum dma_data_direction dma_dir) |
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{ |
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struct vb2_dc_buf *buf; |
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struct frame_vector *vec; |
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unsigned int offset; |
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int n_pages, i; |
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int ret = 0; |
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struct sg_table *sgt; |
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unsigned long contig_size; |
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unsigned long dma_align = dma_get_cache_alignment(); |
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|
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/* Only cache aligned DMA transfers are reliable */ |
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if (!IS_ALIGNED(vaddr | size, dma_align)) { |
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pr_debug("user data must be aligned to %lu bytes\n", dma_align); |
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return ERR_PTR(-EINVAL); |
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} |
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|
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if (!size) { |
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pr_debug("size is zero\n"); |
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return ERR_PTR(-EINVAL); |
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} |
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|
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if (WARN_ON(!dev)) |
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return ERR_PTR(-EINVAL); |
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|
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buf = kzalloc(sizeof *buf, GFP_KERNEL); |
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if (!buf) |
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return ERR_PTR(-ENOMEM); |
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|
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buf->dev = dev; |
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buf->dma_dir = dma_dir; |
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|
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offset = lower_32_bits(offset_in_page(vaddr)); |
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vec = vb2_create_framevec(vaddr, size); |
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if (IS_ERR(vec)) { |
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ret = PTR_ERR(vec); |
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goto fail_buf; |
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} |
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buf->vec = vec; |
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n_pages = frame_vector_count(vec); |
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ret = frame_vector_to_pages(vec); |
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if (ret < 0) { |
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unsigned long *nums = frame_vector_pfns(vec); |
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|
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/* |
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* Failed to convert to pages... Check the memory is physically |
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* contiguous and use direct mapping |
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*/ |
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for (i = 1; i < n_pages; i++) |
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if (nums[i-1] + 1 != nums[i]) |
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goto fail_pfnvec; |
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buf->dma_addr = dma_map_resource(buf->dev, |
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__pfn_to_phys(nums[0]), size, buf->dma_dir, 0); |
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if (dma_mapping_error(buf->dev, buf->dma_addr)) { |
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ret = -ENOMEM; |
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goto fail_pfnvec; |
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} |
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goto out; |
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} |
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|
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sgt = kzalloc(sizeof(*sgt), GFP_KERNEL); |
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if (!sgt) { |
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pr_err("failed to allocate sg table\n"); |
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ret = -ENOMEM; |
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goto fail_pfnvec; |
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} |
|
|
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ret = sg_alloc_table_from_pages(sgt, frame_vector_pages(vec), n_pages, |
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offset, size, GFP_KERNEL); |
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if (ret) { |
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pr_err("failed to initialize sg table\n"); |
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goto fail_sgt; |
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} |
|
|
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/* |
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* No need to sync to the device, this will happen later when the |
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* prepare() memop is called. |
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*/ |
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if (dma_map_sgtable(buf->dev, sgt, buf->dma_dir, |
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DMA_ATTR_SKIP_CPU_SYNC)) { |
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pr_err("failed to map scatterlist\n"); |
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ret = -EIO; |
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goto fail_sgt_init; |
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} |
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|
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contig_size = vb2_dc_get_contiguous_size(sgt); |
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if (contig_size < size) { |
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pr_err("contiguous mapping is too small %lu/%lu\n", |
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contig_size, size); |
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ret = -EFAULT; |
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goto fail_map_sg; |
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} |
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|
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buf->dma_addr = sg_dma_address(sgt->sgl); |
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buf->dma_sgt = sgt; |
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out: |
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buf->size = size; |
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|
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return buf; |
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|
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fail_map_sg: |
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dma_unmap_sgtable(buf->dev, sgt, buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC); |
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|
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fail_sgt_init: |
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sg_free_table(sgt); |
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|
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fail_sgt: |
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kfree(sgt); |
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|
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fail_pfnvec: |
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vb2_destroy_framevec(vec); |
|
|
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fail_buf: |
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kfree(buf); |
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|
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return ERR_PTR(ret); |
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} |
|
|
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/*********************************************/ |
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/* callbacks for DMABUF buffers */ |
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/*********************************************/ |
|
|
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static int vb2_dc_map_dmabuf(void *mem_priv) |
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{ |
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struct vb2_dc_buf *buf = mem_priv; |
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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; |
|
struct dma_buf_map map = DMA_BUF_MAP_INIT_VADDR(buf->vaddr); |
|
|
|
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, &map); |
|
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 <[email protected]>"); |
|
MODULE_LICENSE("GPL");
|
|
|