Hello,
On Thursday, July 26, 2012 1:13 PM Hideki EIRAKU wrote:
> Previously the vb2_dma_contig_mmap() function was using a dma_addr_t as a
> physical address. The two addressses are not necessarily the same.
> For example, when using the IOMMU funtion on certain platforms, dma_addr_t
> addresses are not directly mappable physical address.
> dma_mmap_coherent() maps the address correctly.
> It is available on ARM platforms.
>
> Signed-off-by: Hideki EIRAKU <h...@igel.co.jp>
> ---
> drivers/media/video/videobuf2-dma-contig.c | 18 ++++++++++++++++++
> 1 files changed, 18 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/media/video/videobuf2-dma-contig.c
> b/drivers/media/video/videobuf2-dma-
> contig.c
> index 4b71326..4dc85ab 100644
> --- a/drivers/media/video/videobuf2-dma-contig.c
> +++ b/drivers/media/video/videobuf2-dma-contig.c
> @@ -101,14 +101,32 @@ static unsigned int vb2_dma_contig_num_users(void
> *buf_priv)
> static int vb2_dma_contig_mmap(void *buf_priv, struct vm_area_struct *vma)
> {
> struct vb2_dc_buf *buf = buf_priv;
> +#ifdef ARCH_HAS_DMA_MMAP_COHERENT
> + int ret;
> +#endif
>
> if (!buf) {
> printk(KERN_ERR "No buffer to map\n");
> return -EINVAL;
> }
>
> +#ifdef ARCH_HAS_DMA_MMAP_COHERENT
> + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
The above line is not needed. It is up to dma_mmap_coherent() /
dma_mmap_attrs() to set page
protection bits which match requested type of dma buffer mapping.
> + ret = dma_mmap_coherent(buf->conf->dev, vma, buf->vaddr, buf->dma_addr,
> + buf->size);
> + if (ret) {
> + pr_err("Remapping memory failed, error: %d\n", ret);
> + return ret;
> + }
> + vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
> + vma->vm_private_data = &buf->handler;
> + vma->vm_ops = &vb2_common_vm_ops;
> + vma->vm_ops->open(vma);
> + return 0;
> +#else
> return vb2_mmap_pfn_range(vma, buf->dma_addr, buf->size,
> &vb2_common_vm_ops, &buf->handler);
> +#endif
> }
>
> static void *vb2_dma_contig_get_userptr(void *alloc_ctx, unsigned long vaddr,
Best regards
--
Marek Szyprowski
Samsung Poland R&D Center
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