iommu/ipmmu-vmsa: Link IOMMUs and devices in sysfs

As of commit 7af9a5fd ("iommu/ipmmu-vmsa: Use
iommu_device_sysfs_add()/remove()"), IOMMU devices show up under
/sys/class/iommu/, but their "devices" subdirectories are empty.
Likewise, devices tied to an IOMMU do not have an "iommu" backlink.

Make sure all links are created, on both arm32 and arm64.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/ipmmu-vmsa.c

@@ -885,27 +885,37 @@ static int ipmmu_init_arm_mapping(struct device *dev)
 
 static int ipmmu_add_device(struct device *dev)
 {
+	struct ipmmu_vmsa_device *mmu = to_ipmmu(dev);
 	struct iommu_group *group;
+	int ret;
 
 	/*
 	 * Only let through devices that have been verified in xlate()
 	 */
-	if (!to_ipmmu(dev))
+	if (!mmu)
 		return -ENODEV;
 
-	if (IS_ENABLED(CONFIG_ARM) && !IS_ENABLED(CONFIG_IOMMU_DMA))
-		return ipmmu_init_arm_mapping(dev);
+	if (IS_ENABLED(CONFIG_ARM) && !IS_ENABLED(CONFIG_IOMMU_DMA)) {
+		ret = ipmmu_init_arm_mapping(dev);
+		if (ret)
+			return ret;
+	} else {
+		group = iommu_group_get_for_dev(dev);
+		if (IS_ERR(group))
+			return PTR_ERR(group);
 
-	group = iommu_group_get_for_dev(dev);
-	if (IS_ERR(group))
-		return PTR_ERR(group);
+		iommu_group_put(group);
+	}
 
-	iommu_group_put(group);
+	iommu_device_link(&mmu->iommu, dev);
 	return 0;
 }
 
 static void ipmmu_remove_device(struct device *dev)
 {
+	struct ipmmu_vmsa_device *mmu = to_ipmmu(dev);
+
+	iommu_device_unlink(&mmu->iommu, dev);
 	arm_iommu_detach_device(dev);
 	iommu_group_remove_device(dev);
 }