iommu/arm-smmu: Support v7s context format

Fill in the last bits of machinery required to drive a stage 1 context
bank in v7 short descriptor format. By default we'll prefer to use it
only when the CPUs are also using the same format, such that we're
guaranteed that everything will be strictly 32-bit.
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

drivers/iommu/arm-smmu.c

@@ -217,6 +217,7 @@
 #define ARM_SMMU_CB_TTBR0		0x20
 #define ARM_SMMU_CB_TTBR1		0x28
 #define ARM_SMMU_CB_TTBCR		0x30
+#define ARM_SMMU_CB_CONTEXTIDR		0x34
 #define ARM_SMMU_CB_S1_MAIR0		0x38
 #define ARM_SMMU_CB_S1_MAIR1		0x3c
 #define ARM_SMMU_CB_PAR			0x50
@@ -239,7 +240,6 @@
 #define SCTLR_AFE			(1 << 2)
 #define SCTLR_TRE			(1 << 1)
 #define SCTLR_M				(1 << 0)
-#define SCTLR_EAE_SBOP			(SCTLR_AFE | SCTLR_TRE)
 
 #define ARM_MMU500_ACTLR_CPRE		(1 << 1)
 
@@ -738,7 +738,7 @@ static irqreturn_t arm_smmu_global_fault(int irq, void *dev)
 static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
 				       struct io_pgtable_cfg *pgtbl_cfg)
 {
-	u32 reg;
+	u32 reg, reg2;
 	u64 reg64;
 	bool stage1;
 	struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
@@ -781,14 +781,22 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
 
 	/* TTBRs */
 	if (stage1) {
+		u16 asid = ARM_SMMU_CB_ASID(smmu, cfg);
+
+		if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_S) {
+			reg = pgtbl_cfg->arm_v7s_cfg.ttbr[0];
+			writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBR0);
+			reg = pgtbl_cfg->arm_v7s_cfg.ttbr[1];
+			writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBR1);
+			writel_relaxed(asid, cb_base + ARM_SMMU_CB_CONTEXTIDR);
+		} else {
 			reg64 = pgtbl_cfg->arm_lpae_s1_cfg.ttbr[0];
-
-		reg64 |= ((u64)ARM_SMMU_CB_ASID(smmu, cfg)) << TTBRn_ASID_SHIFT;
+			reg64 |= (u64)asid << TTBRn_ASID_SHIFT;
 			writeq_relaxed(reg64, cb_base + ARM_SMMU_CB_TTBR0);
-
 			reg64 = pgtbl_cfg->arm_lpae_s1_cfg.ttbr[1];
-		reg64 |= ((u64)ARM_SMMU_CB_ASID(smmu, cfg)) << TTBRn_ASID_SHIFT;
+			reg64 |= (u64)asid << TTBRn_ASID_SHIFT;
 			writeq_relaxed(reg64, cb_base + ARM_SMMU_CB_TTBR1);
+		}
 	} else {
 		reg64 = pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
 		writeq_relaxed(reg64, cb_base + ARM_SMMU_CB_TTBR0);
@@ -796,28 +804,36 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
 
 	/* TTBCR */
 	if (stage1) {
+		if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_S) {
+			reg = pgtbl_cfg->arm_v7s_cfg.tcr;
+			reg2 = 0;
+		} else {
 			reg = pgtbl_cfg->arm_lpae_s1_cfg.tcr;
-		writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBCR);
-		if (smmu->version > ARM_SMMU_V1) {
-			reg = pgtbl_cfg->arm_lpae_s1_cfg.tcr >> 32;
-			reg |= TTBCR2_SEP_UPSTREAM;
-			writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBCR2);
+			reg2 = pgtbl_cfg->arm_lpae_s1_cfg.tcr >> 32;
+			reg2 |= TTBCR2_SEP_UPSTREAM;
 		}
+		if (smmu->version > ARM_SMMU_V1)
+			writel_relaxed(reg2, cb_base + ARM_SMMU_CB_TTBCR2);
 	} else {
 		reg = pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
-		writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBCR);
 	}
+	writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBCR);
 
 	/* MAIRs (stage-1 only) */
 	if (stage1) {
+		if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_S) {
+			reg = pgtbl_cfg->arm_v7s_cfg.prrr;
+			reg2 = pgtbl_cfg->arm_v7s_cfg.nmrr;
+		} else {
 			reg = pgtbl_cfg->arm_lpae_s1_cfg.mair[0];
+			reg2 = pgtbl_cfg->arm_lpae_s1_cfg.mair[1];
+		}
 		writel_relaxed(reg, cb_base + ARM_SMMU_CB_S1_MAIR0);
-		reg = pgtbl_cfg->arm_lpae_s1_cfg.mair[1];
-		writel_relaxed(reg, cb_base + ARM_SMMU_CB_S1_MAIR1);
+		writel_relaxed(reg2, cb_base + ARM_SMMU_CB_S1_MAIR1);
 	}
 
 	/* SCTLR */
-	reg = SCTLR_CFIE | SCTLR_CFRE | SCTLR_M | SCTLR_EAE_SBOP;
+	reg = SCTLR_CFIE | SCTLR_CFRE | SCTLR_AFE | SCTLR_TRE | SCTLR_M;
 	if (stage1)
 		reg |= SCTLR_S1_ASIDPNE;
 #ifdef __BIG_ENDIAN
@@ -880,6 +896,11 @@ 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 |
@@ -899,10 +920,14 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
 		oas = smmu->ipa_size;
 		if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH64) {
 			fmt = ARM_64_LPAE_S1;
-		} else {
+		} else if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_L) {
 			fmt = ARM_32_LPAE_S1;
 			ias = min(ias, 32UL);
 			oas = min(oas, 40UL);
+		} else {
+			fmt = ARM_V7S;
+			ias = min(ias, 32UL);
+			oas = min(oas, 32UL);
 		}
 		break;
 	case ARM_SMMU_DOMAIN_NESTED: