iommu/arm-smmu: Favour v7S format if possible

Allow stage 1 contexts to default to short-descriptor format if
supported and all DRAM is 32-bit-addressable.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>

drivers/iommu/arm-smmu.c

@@ -32,6 +32,7 @@
 #include <linux/acpi.h>
 #include <linux/acpi_iort.h>
 #include <linux/atomic.h>
+#include <linux/bootmem.h>
 #include <linux/delay.h>
 #include <linux/dma-iommu.h>
 #include <linux/dma-mapping.h>
@@ -773,16 +774,16 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
 	 */
 	if (smmu->features & ARM_SMMU_FEAT_FMT_AARCH32_L)
 		cfg->fmt = ARM_SMMU_CTX_FMT_AARCH32_L;
-	if (IS_ENABLED(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) &&
-	    !IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_ARM_LPAE) &&
-	    (smmu->features & ARM_SMMU_FEAT_FMT_AARCH32_S) &&
-	    (smmu_domain->stage == ARM_SMMU_DOMAIN_S1))
-		cfg->fmt = ARM_SMMU_CTX_FMT_AARCH32_S;
 	if ((IS_ENABLED(CONFIG_64BIT) || cfg->fmt == ARM_SMMU_CTX_FMT_NONE) &&
 	    (smmu->features & (ARM_SMMU_FEAT_FMT_AARCH64_64K |
 			       ARM_SMMU_FEAT_FMT_AARCH64_16K |
 			       ARM_SMMU_FEAT_FMT_AARCH64_4K)))
 		cfg->fmt = ARM_SMMU_CTX_FMT_AARCH64;
+	if (IS_ENABLED(CONFIG_IOMMU_IO_PGTABLE_ARMV7S) &&
+	    max_pfn <= PFN_DOWN(1ULL << 32) &&
+	    (smmu->features & ARM_SMMU_FEAT_FMT_AARCH32_S) &&
+	    (smmu_domain->stage == ARM_SMMU_DOMAIN_S1))
+		cfg->fmt = ARM_SMMU_CTX_FMT_AARCH32_S;
 
 	if (cfg->fmt == ARM_SMMU_CTX_FMT_NONE) {
 		ret = -EINVAL;