MMU-500 erratum #841119 is tickled by a particular set of circumstances
interacting with the next-page prefetcher. Since said prefetcher is
quite dumb and actually detrimental to performance in some cases (by
causing unwanted TLB evictions for non-sequential access patterns), we
lose very little by turning it off, and what we gain is a guarantee that
the erratum is never hit.
As a bonus, the same workaround will also prevent erratum #826419 once
v7 short descriptor support is implemented.
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
| ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 |
| ARM | Cortex-A57 | #852523 | N/A |
| ARM | Cortex-A57 | #834220 | ARM64_ERRATUM_834220 |
| ARM | Cortex-A57 | #832075 | ARM64_ERRATUM_832075 |
| ARM | Cortex-A57 | #852523 | N/A |
| ARM | Cortex-A57 | #834220 | ARM64_ERRATUM_834220 |
+| ARM | MMU-500 | #841119,#826419 | N/A |
| | | | |
| Cavium | ThunderX ITS | #22375, #24313 | CAVIUM_ERRATUM_22375 |
| Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 |
| | | | |
| Cavium | ThunderX ITS | #22375, #24313 | CAVIUM_ERRATUM_22375 |
| Cavium | ThunderX GICv3 | #23154 | CAVIUM_ERRATUM_23154 |
#define ARM_SMMU_CB(smmu, n) ((n) * (1 << (smmu)->pgshift))
#define ARM_SMMU_CB_SCTLR 0x0
#define ARM_SMMU_CB(smmu, n) ((n) * (1 << (smmu)->pgshift))
#define ARM_SMMU_CB_SCTLR 0x0
+#define ARM_SMMU_CB_ACTLR 0x4
#define ARM_SMMU_CB_RESUME 0x8
#define ARM_SMMU_CB_TTBCR2 0x10
#define ARM_SMMU_CB_TTBR0 0x20
#define ARM_SMMU_CB_RESUME 0x8
#define ARM_SMMU_CB_TTBCR2 0x10
#define ARM_SMMU_CB_TTBR0 0x20
#define SCTLR_M (1 << 0)
#define SCTLR_EAE_SBOP (SCTLR_AFE | SCTLR_TRE)
#define SCTLR_M (1 << 0)
#define SCTLR_EAE_SBOP (SCTLR_AFE | SCTLR_TRE)
+#define ARM_MMU500_ACTLR_CPRE (1 << 1)
+
#define CB_PAR_F (1 << 0)
#define ATSR_ACTIVE (1 << 0)
#define CB_PAR_F (1 << 0)
#define ATSR_ACTIVE (1 << 0)
enum arm_smmu_implementation {
GENERIC_SMMU,
enum arm_smmu_implementation {
GENERIC_SMMU,
cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, i);
writel_relaxed(0, cb_base + ARM_SMMU_CB_SCTLR);
writel_relaxed(FSR_FAULT, cb_base + ARM_SMMU_CB_FSR);
cb_base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, i);
writel_relaxed(0, cb_base + ARM_SMMU_CB_SCTLR);
writel_relaxed(FSR_FAULT, cb_base + ARM_SMMU_CB_FSR);
+ /*
+ * Disable MMU-500's not-particularly-beneficial next-page
+ * prefetcher for the sake of errata #841119 and #826419.
+ */
+ if (smmu->model == ARM_MMU500) {
+ reg = readl_relaxed(cb_base + ARM_SMMU_CB_ACTLR);
+ reg &= ~ARM_MMU500_ACTLR_CPRE;
+ writel_relaxed(reg, cb_base + ARM_SMMU_CB_ACTLR);
+ }
}
/* Invalidate the TLB, just in case */
}
/* Invalidate the TLB, just in case */
ARM_SMMU_MATCH_DATA(smmu_generic_v1, ARM_SMMU_V1, GENERIC_SMMU);
ARM_SMMU_MATCH_DATA(smmu_generic_v2, ARM_SMMU_V2, GENERIC_SMMU);
ARM_SMMU_MATCH_DATA(smmu_generic_v1, ARM_SMMU_V1, GENERIC_SMMU);
ARM_SMMU_MATCH_DATA(smmu_generic_v2, ARM_SMMU_V2, GENERIC_SMMU);
+ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500);
ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2);
static const struct of_device_id arm_smmu_of_match[] = {
ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2);
static const struct of_device_id arm_smmu_of_match[] = {
{ .compatible = "arm,smmu-v2", .data = &smmu_generic_v2 },
{ .compatible = "arm,mmu-400", .data = &smmu_generic_v1 },
{ .compatible = "arm,mmu-401", .data = &smmu_generic_v1 },
{ .compatible = "arm,smmu-v2", .data = &smmu_generic_v2 },
{ .compatible = "arm,mmu-400", .data = &smmu_generic_v1 },
{ .compatible = "arm,mmu-401", .data = &smmu_generic_v1 },
- { .compatible = "arm,mmu-500", .data = &smmu_generic_v2 },
+ { .compatible = "arm,mmu-500", .data = &arm_mmu500 },
{ .compatible = "cavium,smmu-v2", .data = &cavium_smmuv2 },
{ },
};
{ .compatible = "cavium,smmu-v2", .data = &cavium_smmuv2 },
{ },
};