From: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
Introduce the flag "no_size_align" to allow disabling size-alignment
on a per-domain basis. This follows the suggestion by the comment
in the code, however a per-device control may be preferred?
Needed to make virtual space contiguous for certain devices.
Signed-off-by: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
---
drivers/iommu/dma-iommu.c | 6 +++++-
include/linux/iommu.h | 1 +
2 files changed, 6 insertions(+), 1 deletion(-)
--- 0001/drivers/iommu/dma-iommu.c
+++ work/drivers/iommu/dma-iommu.c 2017-01-27 15:17:50.280607110 +0900
@@ -209,14 +209,18 @@ static struct iova *__alloc_iova(struct
struct iova_domain *iovad = cookie_iovad(domain);
unsigned long shift = iova_shift(iovad);
unsigned long length = iova_align(iovad, size) >> shift;
+ bool size_aligned = true;
if (domain->geometry.force_aperture)
dma_limit = min(dma_limit, domain->geometry.aperture_end);
+
+ if (domain->no_size_align)
+ size_aligned = false;
/*
* Enforce size-alignment to be safe - there could perhaps be an
* attribute to control this per-device, or at least per-domain...
*/
- return alloc_iova(iovad, length, dma_limit >> shift, true);
+ return alloc_iova(iovad, length, dma_limit >> shift, size_aligned);
}
/* The IOVA allocator knows what we mapped, so just unmap whatever that was */
--- 0001/include/linux/iommu.h
+++ work/include/linux/iommu.h 2017-01-27 15:16:37.630607110 +0900
@@ -83,6 +83,7 @@ struct iommu_domain {
iommu_fault_handler_t handler;
void *handler_token;
struct iommu_domain_geometry geometry;
+ bool no_size_align;
void *iova_cookie;
};
