@@ -4112,57 +4112,17 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 	/* IDR0 */
 	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR0);
 
-	/* 2-level structures */
-	if (FIELD_GET(IDR0_ST_LVL, reg) == IDR0_ST_LVL_2LVL)
-		smmu->features |= ARM_SMMU_FEAT_2_LVL_STRTAB;
-
-	if (reg & IDR0_CD2L)
-		smmu->features |= ARM_SMMU_FEAT_2_LVL_CDTAB;
-
-	/*
-	 * Translation table endianness.
-	 * We currently require the same endianness as the CPU, but this
-	 * could be changed later by adding a new IO_PGTABLE_QUIRK.
-	 */
-	switch (FIELD_GET(IDR0_TTENDIAN, reg)) {
-	case IDR0_TTENDIAN_MIXED:
-		smmu->features |= ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE;
-		break;
-#ifdef __BIG_ENDIAN
-	case IDR0_TTENDIAN_BE:
-		smmu->features |= ARM_SMMU_FEAT_TT_BE;
-		break;
-#else
-	case IDR0_TTENDIAN_LE:
-		smmu->features |= ARM_SMMU_FEAT_TT_LE;
-		break;
-#endif
-	default:
+	smmu->features |= smmu_idr0_features(reg);
+	if (FIELD_GET(IDR0_TTENDIAN, reg) == IDR0_TTENDIAN_RESERVED) {
 		dev_err(smmu->dev, "unknown/unsupported TT endianness!\n");
 		return -ENXIO;
 	}
-
-	/* Boolean feature flags */
-	if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
-		smmu->features |= ARM_SMMU_FEAT_PRI;
-
-	if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
-		smmu->features |= ARM_SMMU_FEAT_ATS;
-
-	if (reg & IDR0_SEV)
-		smmu->features |= ARM_SMMU_FEAT_SEV;
-
-	if (reg & IDR0_MSI) {
-		smmu->features |= ARM_SMMU_FEAT_MSI;
-		if (coherent && !disable_msipolling)
-			smmu->options |= ARM_SMMU_OPT_MSIPOLL;
-	}
-
-	if (reg & IDR0_HYP) {
-		smmu->features |= ARM_SMMU_FEAT_HYP;
-		if (cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
-			smmu->features |= ARM_SMMU_FEAT_E2H;
-	}
+	if (coherent && !disable_msipolling &&
+	    smmu->features & ARM_SMMU_FEAT_MSI)
+		smmu->options |= ARM_SMMU_OPT_MSIPOLL;
+	if (smmu->features & ARM_SMMU_FEAT_HYP &&
+	    cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
+		smmu->features |= ARM_SMMU_FEAT_E2H;
 
 	arm_smmu_get_httu(smmu, reg);
 

@@ -4174,21 +4134,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 		dev_warn(smmu->dev, "IDR0.COHACC overridden by FW configuration (%s)\n",
 			 str_true_false(coherent));
 
-	switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
-	case IDR0_STALL_MODEL_FORCE:
-		smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
-		fallthrough;
-	case IDR0_STALL_MODEL_STALL:
-		smmu->features |= ARM_SMMU_FEAT_STALLS;
-	}
-
-	if (reg & IDR0_S1P)
-		smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
-
-	if (reg & IDR0_S2P)
-		smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
-
-	if (!(reg & (IDR0_S1P | IDR0_S2P))) {
+	if (!(smmu->features & (ARM_SMMU_FEAT_TRANS_S1 | ARM_SMMU_FEAT_TRANS_S2))) {
 		dev_err(smmu->dev, "no translation support!\n");
 		return -ENXIO;
 	}

@@ -4253,10 +4199,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 
 	/* IDR3 */
 	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
-	if (FIELD_GET(IDR3_RIL, reg))
-		smmu->features |= ARM_SMMU_FEAT_RANGE_INV;
-	if (FIELD_GET(IDR3_FWB, reg))
-		smmu->features |= ARM_SMMU_FEAT_S2FWB;
+	smmu->features |= smmu_idr3_features(reg);
 
 	/* IDR5 */
 	reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5);

@@ -4265,43 +4208,18 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
 	smmu->evtq.max_stalls = FIELD_GET(IDR5_STALL_MAX, reg);
 
 	/* Page sizes */
-	if (reg & IDR5_GRAN64K)
-		smmu->pgsize_bitmap |= SZ_64K | SZ_512M;
-	if (reg & IDR5_GRAN16K)
-		smmu->pgsize_bitmap |= SZ_16K | SZ_32M;
-	if (reg & IDR5_GRAN4K)
-		smmu->pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
+	smmu->pgsize_bitmap = smmu_idr5_to_pgsize(reg);
 
 	/* Input address size */
 	if (FIELD_GET(IDR5_VAX, reg) == IDR5_VAX_52_BIT)
 		smmu->features |= ARM_SMMU_FEAT_VAX;
 
-	/* Output address size */
-	switch (FIELD_GET(IDR5_OAS, reg)) {
-	case IDR5_OAS_32_BIT:
-		smmu->oas = 32;
-		break;
-	case IDR5_OAS_36_BIT:
-		smmu->oas = 36;
-		break;
-	case IDR5_OAS_40_BIT:
-		smmu->oas = 40;
-		break;
-	case IDR5_OAS_42_BIT:
-		smmu->oas = 42;
-		break;
-	case IDR5_OAS_44_BIT:
-		smmu->oas = 44;
-		break;
-	case IDR5_OAS_52_BIT:
-		smmu->oas = 52;
+	smmu->oas = smmu_idr5_to_oas(reg);
+	if (smmu->oas == 52)
 		smmu->pgsize_bitmap |= 1ULL << 42; /* 4TB */
-		break;
-	default:
+	else if (!smmu->oas) {
 		dev_info(smmu->dev,
-			"unknown output address size. Truncating to 48-bit\n");
-		fallthrough;
-	case IDR5_OAS_48_BIT:
+			 "unknown output address size. Truncating to 48-bit\n");
 		smmu->oas = 48;
 	}
 

@@ -26,6 +26,7 @@ struct arm_smmu_device;
 #define IDR0_STALL_MODEL_FORCE		2
 #define IDR0_TTENDIAN			GENMASK(22, 21)
 #define IDR0_TTENDIAN_MIXED		0
+#define IDR0_TTENDIAN_RESERVED	1
 #define IDR0_TTENDIAN_LE		2
 #define IDR0_TTENDIAN_BE		3
 #define IDR0_CD2L			(1 << 19)

@@ -1042,6 +1043,116 @@ static inline void arm_smmu_write_strtab_l1_desc(struct arm_smmu_strtab_l1 *dst,
 	WRITE_ONCE(dst->l2ptr, cpu_to_le64(val));
 }
 
+static inline u32 smmu_idr0_features(u32 reg)
+{
+	u32 features = 0;
+
+	/* 2-level structures */
+	if (FIELD_GET(IDR0_ST_LVL, reg) == IDR0_ST_LVL_2LVL)
+		features |= ARM_SMMU_FEAT_2_LVL_STRTAB;
+
+	if (reg & IDR0_CD2L)
+		features |= ARM_SMMU_FEAT_2_LVL_CDTAB;
+
+	/*
+	 * Translation table endianness.
+	 * We currently require the same endianness as the CPU, but this
+	 * could be changed later by adding a new IO_PGTABLE_QUIRK.
+	 */
+	switch (FIELD_GET(IDR0_TTENDIAN, reg)) {
+	case IDR0_TTENDIAN_MIXED:
+		features |= ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE;
+		break;
+#ifdef __BIG_ENDIAN
+	case IDR0_TTENDIAN_BE:
+		features |= ARM_SMMU_FEAT_TT_BE;
+		break;
+#else
+	case IDR0_TTENDIAN_LE:
+		features |= ARM_SMMU_FEAT_TT_LE;
+		break;
+#endif
+	}
+
+	/* Boolean feature flags */
+	if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
+		features |= ARM_SMMU_FEAT_PRI;
+
+	if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
+		features |= ARM_SMMU_FEAT_ATS;
+
+	if (reg & IDR0_SEV)
+		features |= ARM_SMMU_FEAT_SEV;
+
+	if (reg & IDR0_MSI)
+		features |= ARM_SMMU_FEAT_MSI;
+
+	if (reg & IDR0_HYP)
+		features |= ARM_SMMU_FEAT_HYP;
+
+	switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
+	case IDR0_STALL_MODEL_FORCE:
+		features |= ARM_SMMU_FEAT_STALL_FORCE;
+		fallthrough;
+	case IDR0_STALL_MODEL_STALL:
+		features |= ARM_SMMU_FEAT_STALLS;
+	}
+
+	if (reg & IDR0_S1P)
+		features |= ARM_SMMU_FEAT_TRANS_S1;
+
+	if (reg & IDR0_S2P)
+		features |= ARM_SMMU_FEAT_TRANS_S2;
+
+	return features;
+}
+
+static inline u32 smmu_idr3_features(u32 reg)
+{
+	u32 features = 0;
+
+	if (FIELD_GET(IDR3_RIL, reg))
+		features |= ARM_SMMU_FEAT_RANGE_INV;
+	if (FIELD_GET(IDR3_FWB, reg))
+		features |= ARM_SMMU_FEAT_S2FWB;
+
+	return features;
+}
+
+static inline u32 smmu_idr5_to_oas(u32 reg)
+{
+	switch (FIELD_GET(IDR5_OAS, reg)) {
+	case IDR5_OAS_32_BIT:
+		return 32;
+	case IDR5_OAS_36_BIT:
+		return 36;
+	case IDR5_OAS_40_BIT:
+		return 40;
+	case IDR5_OAS_42_BIT:
+		return 42;
+	case IDR5_OAS_44_BIT:
+		return 44;
+	case IDR5_OAS_48_BIT:
+		return 48;
+	case IDR5_OAS_52_BIT:
+		return 52;
+	}
+	return 0;
+}
+
+static inline unsigned long smmu_idr5_to_pgsize(u32 reg)
+{
+	unsigned long pgsize_bitmap = 0;
+
+	if (reg & IDR5_GRAN64K)
+		pgsize_bitmap |= SZ_64K | SZ_512M;
+	if (reg & IDR5_GRAN16K)
+		pgsize_bitmap |= SZ_16K | SZ_32M;
+	if (reg & IDR5_GRAN4K)
+		pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
+	return pgsize_bitmap;
+}
+
 /**
  * arm_smmu_tlb_inv_build - Create a range invalidation command
  * @cmd: Base command initialized with OPCODE (S1, S2..), vmid and asid.