On Sun, 27 Apr 2014 20:17:48 +0200, Arnd Bergmann wrote:

On Sunday 27 April 2014 13:07:47 Shaik Ameer Basha wrote:

quoted

@@ -542,14 +592,41 @@ static int __init exynos_sysmmu_probe(struct platform_device *pdev)
 		}
 	}
 
+	/* Relation between master and System MMU is 1:1. */
+	node = of_parse_phandle(dev->of_node, "mmu-masters", 0);
+	if (node) {
+		struct platform_device *master = of_find_device_by_node(node);
+
+		if (!master) {
+			dev_err(dev, "%s: mmu-master '%s' not found\n",
+				__func__, node->name);
+			return -EINVAL;
+		}
+
+		if (master->dev.archdata.iommu != NULL) {
+			dev_err(dev, "%s: '%s' is master of other MMU\n",
+				__func__, node->name);
+			return -EINVAL;
+		}
+
+		/*
+		 * archdata.iommu will be initialized with exynos_iommu_client
+		 * in sysmmu_hook_driver_register().
+		 */
+		master->dev.archdata.iommu = dev;
+	}

I think parsing of generic properties like this shouldn't be done
by the individual driver. It belongs into core iommu code and should
be done when the devices are probed.

quoted

+
+static struct notifier_block sysmmu_notifier = {
+	.notifier_call = &sysmmu_hook_driver_register,
+};
+
+static int __init exynos_iommu_prepare(void)
+{
+	static bool registered = false;
+	int ret;
+
+	if (registered)
+		return 0;
+
+	ret = bus_register_notifier(&platform_bus_type, &sysmmu_notifier);
+	if (!ret)
+		registered = true;
+	else
+		pr_err("Failed to register sysmmu_notifier\n");
+
+	return ret;
+}

This also means we should not have notifiers. Put it into core code to
make sure all IOMMUs are handled the same way.

Ok.

Thank you for addressing that.
I am also very interested in the discussion about it in the different thread.

KyongHo