iommu/arm-smmu: Add reset implementation hook
Reset is an activity rife with implementation-defined poking. Add a
corresponding hook, and use it to encapsulate the existing MMU-500
details.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
diff --git a/drivers/iommu/arm-smmu-impl.c b/drivers/iommu/arm-smmu-impl.c
index 6964179..4dc8b1c 100644
--- a/drivers/iommu/arm-smmu-impl.c
+++ b/drivers/iommu/arm-smmu-impl.c
@@ -4,6 +4,7 @@
#define pr_fmt(fmt) "arm-smmu: " fmt
+#include <linux/bitfield.h>
#include <linux/of.h>
#include "arm-smmu.h"
@@ -67,6 +68,51 @@ const struct arm_smmu_impl cavium_impl = {
};
+#define ARM_MMU500_ACTLR_CPRE (1 << 1)
+
+#define ARM_MMU500_ACR_CACHE_LOCK (1 << 26)
+#define ARM_MMU500_ACR_S2CRB_TLBEN (1 << 10)
+#define ARM_MMU500_ACR_SMTNMB_TLBEN (1 << 8)
+
+static int arm_mmu500_reset(struct arm_smmu_device *smmu)
+{
+ u32 reg, major;
+ int i;
+ /*
+ * On MMU-500 r2p0 onwards we need to clear ACR.CACHE_LOCK before
+ * writes to the context bank ACTLRs will stick. And we just hope that
+ * Secure has also cleared SACR.CACHE_LOCK for this to take effect...
+ */
+ reg = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_ID7);
+ major = FIELD_GET(ID7_MAJOR, reg);
+ reg = arm_smmu_gr0_read(smmu, ARM_SMMU_GR0_sACR);
+ if (major >= 2)
+ reg &= ~ARM_MMU500_ACR_CACHE_LOCK;
+ /*
+ * Allow unmatched Stream IDs to allocate bypass
+ * TLB entries for reduced latency.
+ */
+ reg |= ARM_MMU500_ACR_SMTNMB_TLBEN | ARM_MMU500_ACR_S2CRB_TLBEN;
+ arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_sACR, reg);
+
+ /*
+ * Disable MMU-500's not-particularly-beneficial next-page
+ * prefetcher for the sake of errata #841119 and #826419.
+ */
+ for (i = 0; i < smmu->num_context_banks; ++i) {
+ reg = arm_smmu_cb_read(smmu, i, ARM_SMMU_CB_ACTLR);
+ reg &= ~ARM_MMU500_ACTLR_CPRE;
+ arm_smmu_cb_write(smmu, i, ARM_SMMU_CB_ACTLR, reg);
+ }
+
+ return 0;
+}
+
+const struct arm_smmu_impl arm_mmu500_impl = {
+ .reset = arm_mmu500_reset,
+};
+
+
struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
{
/*
@@ -76,6 +122,9 @@ struct arm_smmu_device *arm_smmu_impl_init(struct arm_smmu_device *smmu)
* mutually-exclusive assignments.
*/
switch (smmu->model) {
+ case ARM_MMU500:
+ smmu->impl = &arm_mmu500_impl;
+ break;
case CAVIUM_SMMUV2:
smmu->impl = &cavium_impl;
break;