[PATCH 5/6] iommu/arm-smmu: support buggy implementations with invalidate-on-map

Mitchel Humpherys
2014-08-13T00:51:38Z

Add a workaround for some buggy hardware that requires a TLB invalidate
operation to occur at map time. Activate the feature with the
qcom,smmu-invalidate-on-map boolean DT property.

Signed-off-by: Mitchel Humpherys <mitchelh-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
---
Documentation/devicetree/bindings/iommu/arm,smmu.txt | 4 ++++
drivers/iommu/arm-smmu.c | 14 +++++++++++++-
2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/iommu/arm,smmu.txt b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
index dbc1ddad79..aaebeaeda0 100644
--- a/Documentation/devicetree/bindings/iommu/arm,smmu.txt
+++ b/Documentation/devicetree/bindings/iommu/arm,smmu.txt
@@ -48,6 +48,10 @@ conditions.
aliases of secure registers have to be used during
SMMU configuration.

+- qcom,smmu-invalidate-on-map : Enable proper handling of buggy
+ implementations that require a TLB invalidate
+ operation to occur at map time.
+
- clocks : List of clocks to be used during SMMU register access. See
Documentation/devicetree/bindings/clock/clock-bindings.txt
for information about the format. For each clock specified
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 22e25f3172..73d056668b 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -389,6 +389,7 @@ struct arm_smmu_device {
u32 features;

#define ARM_SMMU_OPT_SECURE_CFG_ACCESS (1 << 0)
+#define ARM_SMMU_OPT_INVALIDATE_ON_MAP (1 << 1)
u32 options;
int version;

@@ -455,6 +456,7 @@ struct arm_smmu_option_prop {

static struct arm_smmu_option_prop arm_smmu_options[] = {
{ ARM_SMMU_OPT_SECURE_CFG_ACCESS, "calxeda,smmu-secure-config-access" },
+ { ARM_SMMU_OPT_INVALIDATE_ON_MAP, "qcom,smmu-invalidate-on-map" },
{ 0, NULL},
};

@@ -1693,12 +1695,22 @@ out_unlock:
static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t size, int prot)
{
+ int ret;
struct arm_smmu_domain *smmu_domain = domain->priv;

if (!smmu_domain)
return -ENODEV;

- return arm_smmu_handle_mapping(smmu_domain, iova, paddr, size, prot);
+ ret = arm_smmu_handle_mapping(smmu_domain, iova, paddr, size, prot);
+
+ if (!ret &&
+ (smmu_domain->smmu->options & ARM_SMMU_OPT_INVALIDATE_ON_MAP)) {
+ arm_smmu_enable_clocks(smmu_domain->smmu);
+ arm_smmu_tlb_inv_context(smmu_domain);
+ arm_smmu_disable_clocks(smmu_domain->smmu);
+ }
+
+ return ret;
}

static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova,