iommu/arm-smmu: use relaxed accessors where possible

Apart from fault handling and page table manipulation, we don't care
about memory ordering between SMMU control registers and normal,
cacheable memory, so use the _relaxed I/O accessors wherever possible.
Signed-off-by: NWill Deacon <will.deacon@arm.com>

drivers/iommu/arm-smmu.c

@@ -778,7 +778,7 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain)
 #ifdef __BIG_ENDIAN
 	reg |= SCTLR_E;
 #endif
-	writel(reg, cb_base + ARM_SMMU_CB_SCTLR);
+	writel_relaxed(reg, cb_base + ARM_SMMU_CB_SCTLR);
 }
 
 static int arm_smmu_init_domain_context(struct iommu_domain *domain,
@@ -1595,7 +1595,7 @@ static void arm_smmu_device_reset(struct arm_smmu_device *smmu)
 
 	/* Push the button */
 	arm_smmu_tlb_sync(smmu);
-	writel(scr0, gr0_base + ARM_SMMU_GR0_sCR0);
+	writel_relaxed(scr0, gr0_base + ARM_SMMU_GR0_sCR0);
 }
 
 static int arm_smmu_id_size_to_bits(int size)
@@ -1928,7 +1928,7 @@ static int arm_smmu_device_remove(struct platform_device *pdev)
 		free_irq(smmu->irqs[i], smmu);
 
 	/* Turn the thing off */
-	writel(sCR0_CLIENTPD, ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_sCR0);
+	writel_relaxed(sCR0_CLIENTPD, ARM_SMMU_GR0(smmu) + ARM_SMMU_GR0_sCR0);
 	return 0;
 }