Revert "iommu/arm-smmu: Convert to domain_alloc_paging()"

This reverts commit 9b3febc3 ("iommu/arm-smmu: Convert to
domain_alloc_paging()"). It breaks Qualcomm MSM8996 platform. Calling
arm_smmu_write_context_bank() from new codepath results in the platform
being reset because of the unclocked hardware access.

Fixes: 9b3febc3 ("iommu/arm-smmu: Convert to domain_alloc_paging()")
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20240213-iommu-revert-domain-alloc-v1-1-325ff55dece4@linaro.orgSigned-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm/arm-smmu/arm-smmu.c

@@ -859,10 +859,14 @@ static void arm_smmu_destroy_domain_context(struct arm_smmu_domain *smmu_domain)
 	arm_smmu_rpm_put(smmu);
 }
 
-static struct iommu_domain *arm_smmu_domain_alloc_paging(struct device *dev)
+static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
 {
 	struct arm_smmu_domain *smmu_domain;
 
+	if (type != IOMMU_DOMAIN_UNMANAGED) {
+		if (using_legacy_binding || type != IOMMU_DOMAIN_DMA)
+			return NULL;
+	}
 	/*
 	 * Allocate the domain and initialise some of its data structures.
 	 * We can't really do anything meaningful until we've added a
@@ -875,15 +879,6 @@ static struct iommu_domain *arm_smmu_domain_alloc_paging(struct device *dev)
 	mutex_init(&smmu_domain->init_mutex);
 	spin_lock_init(&smmu_domain->cb_lock);
 
-	if (dev) {
-		struct arm_smmu_master_cfg *cfg = dev_iommu_priv_get(dev);
-
-		if (arm_smmu_init_domain_context(smmu_domain, cfg->smmu, dev)) {
-			kfree(smmu_domain);
-			return NULL;
-		}
-	}
-
 	return &smmu_domain->domain;
 }
 
@@ -1600,7 +1595,7 @@ static struct iommu_ops arm_smmu_ops = {
 	.identity_domain	= &arm_smmu_identity_domain,
 	.blocked_domain		= &arm_smmu_blocked_domain,
 	.capable		= arm_smmu_capable,
-	.domain_alloc_paging	= arm_smmu_domain_alloc_paging,
+	.domain_alloc		= arm_smmu_domain_alloc,
 	.probe_device		= arm_smmu_probe_device,
 	.release_device		= arm_smmu_release_device,
 	.probe_finalize		= arm_smmu_probe_finalize,