iommu/sprd: Release dma buffer to avoid memory leak

When attaching to a domain, the driver would alloc a DMA buffer which
is used to store address mapping table, and it need to be released
when the IOMMU domain is freed.
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Link: https://lore.kernel.org/r/20230331033124.864691-2-zhang.lyra@gmail.comSigned-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/sprd-iommu.c

@@ -151,13 +151,6 @@ static struct iommu_domain *sprd_iommu_domain_alloc(unsigned int domain_type)
 	return &dom->domain;
 }
 
-static void sprd_iommu_domain_free(struct iommu_domain *domain)
-{
-	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
-
-	kfree(dom);
-}
-
 static void sprd_iommu_first_vpn(struct sprd_iommu_domain *dom)
 {
 	struct sprd_iommu_device *sdev = dom->sdev;
@@ -230,6 +223,28 @@ static void sprd_iommu_hw_en(struct sprd_iommu_device *sdev, bool en)
 	sprd_iommu_update_bits(sdev, reg_cfg, mask, 0, val);
 }
 
+static void sprd_iommu_cleanup(struct sprd_iommu_domain *dom)
+{
+	size_t pgt_size;
+
+	/* Nothing need to do if the domain hasn't been attached */
+	if (!dom->sdev)
+		return;
+
+	pgt_size = sprd_iommu_pgt_size(&dom->domain);
+	dma_free_coherent(dom->sdev->dev, pgt_size, dom->pgt_va, dom->pgt_pa);
+	dom->sdev = NULL;
+	sprd_iommu_hw_en(dom->sdev, false);
+}
+
+static void sprd_iommu_domain_free(struct iommu_domain *domain)
+{
+	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
+
+	sprd_iommu_cleanup(dom);
+	kfree(dom);
+}
+
 static int sprd_iommu_attach_device(struct iommu_domain *domain,
 				    struct device *dev)
 {