diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 59ee4b8..bdb85b5 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -33,6 +33,7 @@
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/io-64-nonatomic-hi-lo.h>
 #include <linux/iommu.h>
 #include <linux/iopoll.h>
 #include <linux/module.h>
@@ -70,16 +71,15 @@
 		((smmu->options & ARM_SMMU_OPT_SECURE_CFG_ACCESS)	\
 			? 0x400 : 0))
 
+/*
+ * Some 64-bit registers only make sense to write atomically, but in such
+ * cases all the data relevant to AArch32 formats lies within the lower word,
+ * therefore this actually makes more sense than it might first appear.
+ */
 #ifdef CONFIG_64BIT
-#define smmu_writeq	writeq_relaxed
+#define smmu_write_atomic_lq		writeq_relaxed
 #else
-#define smmu_writeq(reg64, addr)				\
-	do {							\
-		u64 __val = (reg64);				\
-		void __iomem *__addr = (addr);			\
-		writel_relaxed(__val >> 32, __addr + 4);	\
-		writel_relaxed(__val, __addr);			\
-	} while (0)
+#define smmu_write_atomic_lq		writel_relaxed
 #endif
 
 /* Configuration registers */
@@ -202,11 +202,9 @@
 #define ARM_SMMU_CB_TTBCR		0x30
 #define ARM_SMMU_CB_S1_MAIR0		0x38
 #define ARM_SMMU_CB_S1_MAIR1		0x3c
-#define ARM_SMMU_CB_PAR_LO		0x50
-#define ARM_SMMU_CB_PAR_HI		0x54
+#define ARM_SMMU_CB_PAR			0x50
 #define ARM_SMMU_CB_FSR			0x58
-#define ARM_SMMU_CB_FAR_LO		0x60
-#define ARM_SMMU_CB_FAR_HI		0x64
+#define ARM_SMMU_CB_FAR			0x60
 #define ARM_SMMU_CB_FSYNR0		0x68
 #define ARM_SMMU_CB_S1_TLBIVA		0x600
 #define ARM_SMMU_CB_S1_TLBIASID		0x610
@@ -618,7 +616,7 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
 			      ARM_SMMU_CB_S2_TLBIIPAS2;
 		iova >>= 12;
 		do {
-			writeq_relaxed(iova, reg);
+			smmu_write_atomic_lq(iova, reg);
 			iova += granule >> 12;
 		} while (size -= granule);
 #endif
@@ -637,7 +635,7 @@ static struct iommu_gather_ops arm_smmu_gather_ops = {
 static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
 {
 	int flags, ret;
-	u32 fsr, far, fsynr, resume;
+	u32 fsr, fsynr, resume;
 	unsigned long iova;
 	struct iommu_domain *domain = dev;
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
@@ -659,13 +657,7 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
 	fsynr = readl_relaxed(cb_base + ARM_SMMU_CB_FSYNR0);
 	flags = fsynr & FSYNR0_WNR ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ;
 
-	far = readl_relaxed(cb_base + ARM_SMMU_CB_FAR_LO);
-	iova = far;
-#ifdef CONFIG_64BIT
-	far = readl_relaxed(cb_base + ARM_SMMU_CB_FAR_HI);
-	iova |= ((unsigned long)far << 32);
-#endif
-
+	iova = readq_relaxed(cb_base + ARM_SMMU_CB_FAR);
 	if (!report_iommu_fault(domain, smmu->dev, iova, flags)) {
 		ret = IRQ_HANDLED;
 		resume = RESUME_RETRY;
@@ -761,14 +753,14 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
 		reg64 = pgtbl_cfg->arm_lpae_s1_cfg.ttbr[0];
 
 		reg64 |= ((u64)ARM_SMMU_CB_ASID(cfg)) << TTBRn_ASID_SHIFT;
-		smmu_writeq(reg64, cb_base + ARM_SMMU_CB_TTBR0);
+		writeq_relaxed(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;
-		smmu_writeq(reg64, cb_base + ARM_SMMU_CB_TTBR1);
+		writeq_relaxed(reg64, cb_base + ARM_SMMU_CB_TTBR1);
 	} else {
 		reg64 = pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
-		smmu_writeq(reg64, cb_base + ARM_SMMU_CB_TTBR0);
+		writeq_relaxed(reg64, cb_base + ARM_SMMU_CB_TTBR0);
 	}
 
 	/* TTBCR */
@@ -1226,8 +1218,8 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
 	/* ATS1 registers can only be written atomically */
 	va = iova & ~0xfffUL;
 	if (smmu->version == ARM_SMMU_V2)
-		smmu_writeq(va, cb_base + ARM_SMMU_CB_ATS1PR);
-	else
+		smmu_write_atomic_lq(va, cb_base + ARM_SMMU_CB_ATS1PR);
+	else /* Register is only 32-bit in v1 */
 		writel_relaxed(va, cb_base + ARM_SMMU_CB_ATS1PR);
 
 	if (readl_poll_timeout_atomic(cb_base + ARM_SMMU_CB_ATSR, tmp,
@@ -1238,9 +1230,7 @@ static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,
 		return ops->iova_to_phys(ops, iova);
 	}
 
-	phys = readl_relaxed(cb_base + ARM_SMMU_CB_PAR_LO);
-	phys |= ((u64)readl_relaxed(cb_base + ARM_SMMU_CB_PAR_HI)) << 32;
-
+	phys = readq_relaxed(cb_base + ARM_SMMU_CB_PAR);
 	if (phys & CB_PAR_F) {
 		dev_err(dev, "translation fault!\n");
 		dev_err(dev, "PAR = 0x%llx\n", phys);
