From b2e4f95f27838429584ff43b38aaa848dbb9db96 Mon Sep 17 00:00:00 2001
From: Johannes Schlatow <johannes.schlatow@genode-labs.com>
Date: Fri, 20 Jan 2023 18:10:19 +0100
Subject: [PATCH] platform_drv: add <io_mmu> to devices ROM

This allows referencing an arbitrary number of IOMMU devices within a
<devices> node, e.g.:

<device>
  <io_mmu name="foobar"/>
</device>

The specified name is supposed to refer to an existing device in the
devices ROM. The platform driver automatically acquires known IOMMU
devices whenever they become available so that the device object can be
looked up from the platform-driver-owned devices.

genodelabs/genode#4761
---
 repos/os/src/drivers/platform/device.h        | 55 +++++++++++++++++++
 .../drivers/platform/device_model_policy.cc   | 10 ++++
 2 files changed, 65 insertions(+)

diff --git a/repos/os/src/drivers/platform/device.h b/repos/os/src/drivers/platform/device.h
index 9871f491e7..a6f76ec075 100644
--- a/repos/os/src/drivers/platform/device.h
+++ b/repos/os/src/drivers/platform/device.h
@@ -47,6 +47,7 @@ namespace Driver {
 	struct Power_domain_update_policy;
 	struct Pci_config_update_policy;
 	struct Reserved_memory_update_policy;
+	struct Io_mmu_update_policy;
 }
 
 
@@ -211,6 +212,15 @@ class Driver::Device : private List_model<Device>::Element
 			Reserved_memory(Range range) : range(range) {}
 		};
 
+		struct Io_mmu : List_model<Io_mmu>::Element
+		{
+			using Name = Genode::String<64>;
+
+			Name name;
+
+			Io_mmu(Name name) : name(name) {}
+		};
+
 		Device(Env & env, Device_model & model, Name name, Type type,
 		       bool leave_operational);
 		virtual ~Device();
@@ -269,6 +279,19 @@ class Driver::Device : private List_model<Device>::Element
 				fn(idx++, mem.range); });
 		}
 
+		template <typename FN, typename EMPTY_FN>
+		void for_each_io_mmu(FN const & fn, EMPTY_FN const & empty_fn) const
+		{
+			bool empty = true;
+			_io_mmu_list.for_each([&] (Io_mmu const & io_mmu) {
+				empty = false;
+				fn(io_mmu);
+			});
+
+			if (empty)
+				empty_fn();
+		}
+
 		void generate(Xml_generator &, bool) const;
 
 	protected:
@@ -292,6 +315,7 @@ class Driver::Device : private List_model<Device>::Element
 		List_model<Reset_domain>    _reset_domain_list {};
 		List_model<Pci_config>      _pci_config_list {};
 		List_model<Reserved_memory> _reserved_mem_list {};
+		List_model<Io_mmu>          _io_mmu_list {};
 
 		/*
 		 * Noncopyable
@@ -705,4 +729,35 @@ struct Driver::Reserved_memory_update_policy
 	}
 };
 
+
+struct Driver::Io_mmu_update_policy
+: Genode::List_model<Device::Io_mmu>::Update_policy
+{
+	Genode::Allocator & alloc;
+
+	Io_mmu_update_policy(Genode::Allocator & alloc) : alloc(alloc) {}
+
+	void destroy_element(Element & pd) {
+		Genode::destroy(alloc, &pd); }
+
+	Element & create_element(Genode::Xml_node node)
+	{
+		Element::Name name = node.attribute_value("name", Element::Name());
+		return *(new (alloc) Element(name));
+	}
+
+	void update_element(Element &, Genode::Xml_node) {}
+
+	static bool element_matches_xml_node(Element const & e, Genode::Xml_node node)
+	{
+		Element::Name name = node.attribute_value("name", Element::Name());
+		return name == e.name;
+	}
+
+	static bool node_is_element(Genode::Xml_node node)
+	{
+		return node.has_type("io_mmu");
+	}
+};
+
 #endif /* _SRC__DRIVERS__PLATFORM__DEVICE_H_ */
diff --git a/repos/os/src/drivers/platform/device_model_policy.cc b/repos/os/src/drivers/platform/device_model_policy.cc
index 8dbfd9e394..92d19a36dd 100644
--- a/repos/os/src/drivers/platform/device_model_policy.cc
+++ b/repos/os/src/drivers/platform/device_model_policy.cc
@@ -63,6 +63,11 @@ void Device_model::destroy_element(Device & device)
 		device._reserved_mem_list.destroy_all_elements(policy);
 	}
 
+	{
+		Io_mmu_update_policy policy(_heap);
+		device._io_mmu_list.destroy_all_elements(policy);
+	}
+
 	device.release(_owner);
 	Genode::destroy(_heap, &device);
 }
@@ -124,4 +129,9 @@ void Device_model::update_element(Device & device,
 		Reserved_memory_update_policy policy(_heap);
 		device._reserved_mem_list.update_from_xml(policy, node);
 	}
+
+	{
+		Io_mmu_update_policy policy(_heap);
+		device._io_mmu_list.update_from_xml(policy, node);
+	}
 }