Hi
On 2016-06-08 20:31, Matthew Leach wrote:
From: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
Add initial support for big endian by always writing the pte
in le32. Note, revisit if hardware capable of doing big endian
fetches.
Signed-off-by: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Just to keep my curiosity satisfied - what's the reason to use
big-endian on ARM?
Good luck with fixing the kernel and userspace codes, which usually
assume little-endian is the only possible order!
---
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Kukjin Kim <kgene@xxxxxxxxxx>
Cc: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-samsung-soc@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx (open list)
---
drivers/iommu/exynos-iommu.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 5ecc86c..dd8b3b3 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -54,6 +54,10 @@ typedef u32 sysmmu_pte_t;
#define lv2ent_small(pent) ((*(pent) & 2) == 2)
#define lv2ent_large(pent) ((*(pent) & 3) == 1)
+#ifdef CONFIG_BIG_ENDIAN
+#warning "revisit driver if we can enable big-endian ptes"
+#endif
+
This warning can be removed. There is no way to force SYSMMU to operate with
big-endian PTEs according to the datasheet.
/*
* v1.x - v3.x SYSMMU supports 32bit physical and 32bit virtual address spaces
* v5.0 introduced support for 36bit physical address space by shifting
@@ -716,7 +720,7 @@ static inline void update_pte(sysmmu_pte_t *ent, sysmmu_pte_t val)
{
dma_sync_single_for_cpu(dma_dev, virt_to_phys(ent), sizeof(*ent),
DMA_TO_DEVICE);
- *ent = val;
+ *ent = cpu_to_le32(val);
dma_sync_single_for_device(dma_dev, virt_to_phys(ent), sizeof(*ent),
DMA_TO_DEVICE);
}
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
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