iommu/arm-smmu-v3: Add context descriptor tables allocators

Support for SSID will require allocating context descriptor tables. Move
the context descriptor allocation to separate functions.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm-smmu-v3.c

@@ -552,11 +552,13 @@ struct arm_smmu_ctx_desc {
 struct arm_smmu_ctx_desc_cfg {
 	__le64				*cdtab;
 	dma_addr_t			cdtab_dma;
+	unsigned int			num_l1_ents;
 };
 
 struct arm_smmu_s1_cfg {
 	struct arm_smmu_ctx_desc_cfg	cdcfg;
 	struct arm_smmu_ctx_desc	cd;
+	u8				s1cdmax;
 };
 
 struct arm_smmu_s2_cfg {
@@ -1475,6 +1477,35 @@ static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu,
 	cdptr[3] = cpu_to_le64(cfg->cd.mair);
 }
 
+static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain)
+{
+	size_t l1size;
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &cfg->cdcfg;
+
+	cdcfg->num_l1_ents = 1UL << cfg->s1cdmax;
+	l1size = cdcfg->num_l1_ents * (CTXDESC_CD_DWORDS << 3);
+	cdcfg->cdtab = dmam_alloc_coherent(smmu->dev, l1size, &cdcfg->cdtab_dma,
+					   GFP_KERNEL);
+	if (!cdcfg->cdtab) {
+		dev_warn(smmu->dev, "failed to allocate context descriptor\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static void arm_smmu_free_cd_tables(struct arm_smmu_domain *smmu_domain)
+{
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->s1_cfg.cdcfg;
+	size_t l1size = cdcfg->num_l1_ents * (CTXDESC_CD_DWORDS << 3);
+
+	dmam_free_coherent(smmu->dev, l1size, cdcfg->cdtab, cdcfg->cdtab_dma);
+	cdcfg->cdtab_dma = 0;
+	cdcfg->cdtab = NULL;
+}
+
 /* Stream table manipulation functions */
 static void
 arm_smmu_write_strtab_l1_desc(__le64 *dst, struct arm_smmu_strtab_l1_desc *desc)
@@ -2118,11 +2149,7 @@ static void arm_smmu_domain_free(struct iommu_domain *domain)
 		struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
 
 		if (cfg->cdcfg.cdtab) {
-			dmam_free_coherent(smmu_domain->smmu->dev,
-					   CTXDESC_CD_DWORDS << 3,
-					   cfg->cdcfg.cdtab,
-					   cfg->cdcfg.cdtab_dma);
-
+			arm_smmu_free_cd_tables(smmu_domain);
 			arm_smmu_bitmap_free(smmu->asid_map, cfg->cd.asid);
 		}
 	} else {
@@ -2147,15 +2174,9 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (asid < 0)
 		return asid;
 
-	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;
+	ret = arm_smmu_alloc_cd_tables(smmu_domain);
+	if (ret)
 		goto out_free_asid;
-	}
 
 	cfg->cd.asid	= (u16)asid;
 	cfg->cd.ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr;