RE: [PATCH v2 3/4] media: videobuf2-dma-contig: use dma_mmap_coherent if available
From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: 2012-07-30 07:43:39
Also in:
linux-arm-kernel, linux-fbdev, linux-media, lkml
Hello, On Thursday, July 26, 2012 1:13 PM Hideki EIRAKU wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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