From: Robin Murphy <robin.murphy@xxxxxxx>
On some platforms, MMIO regions might need slightly different treatment
compared to mapping regular memory; add the notion of MMIO mappings to
the IOMMU API's memory type flags, so that callers can let the IOMMU
drivers know to do the right thing.
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
---
drivers/iommu/io-pgtable-arm.c | 9 +++++++--
include/linux/iommu.h | 1 +
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 381ca5a..9c19989 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -355,7 +355,10 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
if (!(prot & IOMMU_WRITE) && (prot & IOMMU_READ))
pte |= ARM_LPAE_PTE_AP_RDONLY;
- if (prot & IOMMU_CACHE)
+ if (prot & IOMMU_MMIO)
+ pte |= (ARM_LPAE_MAIR_ATTR_IDX_DEV
+ << ARM_LPAE_PTE_ATTRINDX_SHIFT);
+ else if (prot & IOMMU_CACHE)
pte |= (ARM_LPAE_MAIR_ATTR_IDX_CACHE
<< ARM_LPAE_PTE_ATTRINDX_SHIFT);
} else {
@@ -364,7 +367,9 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data,
pte |= ARM_LPAE_PTE_HAP_READ;
if (prot & IOMMU_WRITE)
pte |= ARM_LPAE_PTE_HAP_WRITE;
- if (prot & IOMMU_CACHE)
+ if (prot & IOMMU_MMIO)
+ pte |= ARM_LPAE_PTE_MEMATTR_DEV;
+ else if (prot & IOMMU_CACHE)
pte |= ARM_LPAE_PTE_MEMATTR_OIWB;
else
pte |= ARM_LPAE_PTE_MEMATTR_NC;
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index a5c539f..34b6432 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -30,6 +30,7 @@
#define IOMMU_WRITE (1 << 1)
#define IOMMU_CACHE (1 << 2) /* DMA cache coherency */
#define IOMMU_NOEXEC (1 << 3)
+#define IOMMU_MMIO (1 << 4) /* e.g. things like MSI doorbells */
struct iommu_ops;
struct iommu_group;
--
2.7.1
