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Subject[PATCH v2 3/4] media: videobuf2-dma-contig: use dma_mmap_coherent if available
Date
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 <hdk@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);
+ 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,
--
1.7.0.4


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