iommu/arm-smmu-v3: Prepare arm_smmu_s1_cfg for SSID support

When adding SSID support to the SMMUv3 driver, we'll need to manipulate
leaf pasid tables and context descriptors. Extract the context
descriptor structure and align with the way stream tables are handled.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm-smmu-v3.c

@@ -542,16 +542,21 @@ struct arm_smmu_strtab_l1_desc {
 	dma_addr_t			l2ptr_dma;
 };
 
+struct arm_smmu_ctx_desc {
+	u16				asid;
+	u64				ttbr;
+	u64				tcr;
+	u64				mair;
+};
+
+struct arm_smmu_ctx_desc_cfg {
+	__le64				*cdtab;
+	dma_addr_t			cdtab_dma;
+};
+
 struct arm_smmu_s1_cfg {
-	__le64				*cdptr;
-	dma_addr_t			cdptr_dma;
-
-	struct arm_smmu_ctx_desc {
-		u16	asid;
-		u64	ttbr;
-		u64	tcr;
-		u64	mair;
-	}				cd;
+	struct arm_smmu_ctx_desc_cfg	cdcfg;
+	struct arm_smmu_ctx_desc	cd;
 };
 
 struct arm_smmu_s2_cfg {
@@ -1444,6 +1449,7 @@ static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu,
 				    struct arm_smmu_s1_cfg *cfg)
 {
 	u64 val;
+	__le64 *cdptr = cfg->cdcfg.cdtab;
 
 	/*
 	 * We don't need to issue any invalidation here, as we'll invalidate
@@ -1461,12 +1467,12 @@ static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu,
 	if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE)
 		val |= CTXDESC_CD_0_S;
 
-	cfg->cdptr[0] = cpu_to_le64(val);
+	cdptr[0] = cpu_to_le64(val);
 
 	val = cfg->cd.ttbr & CTXDESC_CD_1_TTB0_MASK;
-	cfg->cdptr[1] = cpu_to_le64(val);
+	cdptr[1] = cpu_to_le64(val);
 
-	cfg->cdptr[3] = cpu_to_le64(cfg->cd.mair);
+	cdptr[3] = cpu_to_le64(cfg->cd.mair);
 }
 
 /* Stream table manipulation functions */
@@ -1597,7 +1603,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 		   !(smmu->features & ARM_SMMU_FEAT_STALL_FORCE))
 			dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);
 
-		val |= (s1_cfg->cdptr_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
+		val |= (s1_cfg->cdcfg.cdtab_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
 			FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS);
 	}
 
@@ -2111,11 +2117,11 @@ static void arm_smmu_domain_free(struct iommu_domain *domain)
 	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
 		struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
 
-		if (cfg->cdptr) {
+		if (cfg->cdcfg.cdtab) {
 			dmam_free_coherent(smmu_domain->smmu->dev,
 					   CTXDESC_CD_DWORDS << 3,
-					   cfg->cdptr,
-					   cfg->cdptr_dma);
+					   cfg->cdcfg.cdtab,
+					   cfg->cdcfg.cdtab_dma);
 
 			arm_smmu_bitmap_free(smmu->asid_map, cfg->cd.asid);
 		}
@@ -2141,9 +2147,11 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (asid < 0)
 		return asid;
 
-	cfg->cdptr = dmam_alloc_coherent(smmu->dev, CTXDESC_CD_DWORDS << 3,
-					 &cfg->cdptr_dma, GFP_KERNEL);
-	if (!cfg->cdptr) {
+	cfg->cdcfg.cdtab = dmam_alloc_coherent(smmu->dev,
+					       CTXDESC_CD_DWORDS << 3,
+					       &cfg->cdcfg.cdtab_dma,
+					       GFP_KERNEL);
+	if (!cfg->cdcfg.cdtab) {
 		dev_warn(smmu->dev, "failed to allocate context descriptor\n");
 		ret = -ENOMEM;
 		goto out_free_asid;