iommu/arm-smmu: Workaround for ThunderX erratum #27704

Due to erratum #27704, the CN88xx SMMUv2 implementation supports only
shared ASID and VMID numberspaces.

This patch ensures that ASID and VMIDs are unique across all SMMU
instances on affected Cavium systems.

Signed-off-by: Tirumalesh Chalamarla <tchalamarla@caviumnetworks.com>
Signed-off-by: Akula Geethasowjanya <Geethasowjanya.Akula@caviumnetworks.com>
[will: commit message, comments and formatting]
Signed-off-by: Will Deacon <will.deacon@arm.com>

1 files changed, 28 insertions, 11 deletions

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 25e884a75f6b..e933679a3266 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -334,6 +334,8 @@ struct arm_smmu_device {
 
         struct list_head                list;
         struct rb_root                  masters;
+
+        u32                             cavium_id_base; /* Specific to Cavium */
 };
 
 struct arm_smmu_cfg {
@@ -343,8 +345,8 @@ struct arm_smmu_cfg {
 };
 #define INVALID_IRPTNDX                 0xff
 
-#define ARM_SMMU_CB_ASID(cfg)           ((cfg)->cbndx)
-#define ARM_SMMU_CB_VMID(cfg)           ((cfg)->cbndx + 1)
+#define ARM_SMMU_CB_ASID(smmu, cfg) ((u16)(smmu)->cavium_id_base + (cfg)->cbndx)
+#define ARM_SMMU_CB_VMID(smmu, cfg) ((u16)(smmu)->cavium_id_base + (cfg)->cbndx + 1)
 
 enum arm_smmu_domain_stage {
         ARM_SMMU_DOMAIN_S1 = 0,
@@ -372,6 +374,8 @@ struct arm_smmu_option_prop {
         const char *prop;
 };
 
+static atomic_t cavium_smmu_context_count = ATOMIC_INIT(0);
+
 static struct arm_smmu_option_prop arm_smmu_options[] = {
         { ARM_SMMU_OPT_SECURE_CFG_ACCESS, "calxeda,smmu-secure-config-access" },
         { 0, NULL},
@@ -583,11 +587,11 @@ static void arm_smmu_tlb_inv_context(void *cookie)
 
         if (stage1) {
                 base = ARM_SMMU_CB_BASE(smmu) + ARM_SMMU_CB(smmu, cfg->cbndx);
-                writel_relaxed(ARM_SMMU_CB_ASID(cfg),
+                writel_relaxed(ARM_SMMU_CB_ASID(smmu, cfg),
                                base + ARM_SMMU_CB_S1_TLBIASID);
         } else {
                 base = ARM_SMMU_GR0(smmu);
-                writel_relaxed(ARM_SMMU_CB_VMID(cfg),
+                writel_relaxed(ARM_SMMU_CB_VMID(smmu, cfg),
                                base + ARM_SMMU_GR0_TLBIVMID);
         }
 
@@ -609,7 +613,7 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
 
                 if (!IS_ENABLED(CONFIG_64BIT) || smmu->version == ARM_SMMU_V1) {
                         iova &= ~12UL;
-                        iova |= ARM_SMMU_CB_ASID(cfg);
+                        iova |= ARM_SMMU_CB_ASID(smmu, cfg);
                         do {
                                 writel_relaxed(iova, reg);
                                 iova += granule;
@@ -617,7 +621,7 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
 #ifdef CONFIG_64BIT
                 } else {
                         iova >>= 12;
-                        iova |= (u64)ARM_SMMU_CB_ASID(cfg) << 48;
+                        iova |= (u64)ARM_SMMU_CB_ASID(smmu, cfg) << 48;
                         do {
                                 writeq_relaxed(iova, reg);
                                 iova += granule >> 12;
@@ -637,7 +641,7 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
 #endif
         } else {
                 reg = ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_TLBIVMID;
-                writel_relaxed(ARM_SMMU_CB_VMID(cfg), reg);
+                writel_relaxed(ARM_SMMU_CB_VMID(smmu, cfg), reg);
         }
 }
 
@@ -746,7 +750,7 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
 #endif
                 /* 16-bit VMIDs live in CBA2R */
                 if (smmu->features & ARM_SMMU_FEAT_VMID16)
-                        reg |= ARM_SMMU_CB_VMID(cfg) << CBA2R_VMID_SHIFT;
+                        reg |= ARM_SMMU_CB_VMID(smmu, cfg) << CBA2R_VMID_SHIFT;
 
                 writel_relaxed(reg, gr1_base + ARM_SMMU_GR1_CBA2R(cfg->cbndx));
         }
@@ -765,7 +769,7 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
                         (CBAR_S1_MEMATTR_WB << CBAR_S1_MEMATTR_SHIFT);
         } else if (!(smmu->features & ARM_SMMU_FEAT_VMID16)) {
                 /* 8-bit VMIDs live in CBAR */
-                reg |= ARM_SMMU_CB_VMID(cfg) << CBAR_VMID_SHIFT;
+                reg |= ARM_SMMU_CB_VMID(smmu, cfg) << CBAR_VMID_SHIFT;
         }
         writel_relaxed(reg, gr1_base + ARM_SMMU_GR1_CBAR(cfg->cbndx));
 
@@ -773,11 +777,11 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
         if (stage1) {
                 reg64 = pgtbl_cfg->arm_lpae_s1_cfg.ttbr[0];
 
-                reg64 |= ((u64)ARM_SMMU_CB_ASID(cfg)) << TTBRn_ASID_SHIFT;
+                reg64 |= ((u64)ARM_SMMU_CB_ASID(smmu, cfg)) << TTBRn_ASID_SHIFT;
                 smmu_writeq(reg64, cb_base + ARM_SMMU_CB_TTBR0);
 
                 reg64 = pgtbl_cfg->arm_lpae_s1_cfg.ttbr[1];
-                reg64 |= ((u64)ARM_SMMU_CB_ASID(cfg)) << TTBRn_ASID_SHIFT;
+                reg64 |= ((u64)ARM_SMMU_CB_ASID(smmu, cfg)) << TTBRn_ASID_SHIFT;
                 smmu_writeq(reg64, cb_base + ARM_SMMU_CB_TTBR1);
         } else {
                 reg64 = pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
@@ -1737,6 +1741,7 @@ static const struct of_device_id arm_smmu_of_match[] = {
         { .compatible = "arm,mmu-400", .data = (void *)ARM_SMMU_V1 },
         { .compatible = "arm,mmu-401", .data = (void *)ARM_SMMU_V1 },
         { .compatible = "arm,mmu-500", .data = (void *)ARM_SMMU_V2 },
+        { .compatible = "cavium,smmu-v2", .data = (void *)ARM_SMMU_V2 },
         { },
 };
 MODULE_DEVICE_TABLE(of, arm_smmu_of_match);
@@ -1847,6 +1852,18 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev)
                 }
         }
 
+        /*
+         * Cavium CN88xx erratum #27704.
+         * Ensure ASID and VMID allocation is unique across all SMMUs in
+         * the system.
+         */
+        if (of_device_is_compatible(dev->of_node, "cavium,smmu-v2")) {
+                smmu->cavium_id_base =
+                        atomic_add_return(smmu->num_context_banks,
+                                          &cavium_smmu_context_count);
+                smmu->cavium_id_base -= smmu->num_context_banks;
+        }
+
         INIT_LIST_HEAD(&smmu->list);
         spin_lock(&arm_smmu_devices_lock);
         list_add(&smmu->list, &arm_smmu_devices);