platform_drv: implement shared interrupt support

Ref genodelabs/genode#4578

repos/os/src/drivers/platform/device.cc

@@ -11,6 +11,8 @@
  * under the terms of the GNU Affero General Public License version 3.
  */
 
+#include <util/bit_array.h>
+
 #include <device.h>
 #include <pci.h>
 #include <device_component.h>
@@ -137,6 +139,7 @@ void Driver::Device::generate(Xml_generator & xml, bool info) const
 				if (!info)
 					return;
 				xml.attribute("number", irq.number);
+				if (irq.shared) xml.attribute("shared", true);
 			});
 		});
 		_io_port_range_list.for_each([&] (Io_port_range const & iop) {
@@ -206,6 +209,52 @@ void Driver::Device_model::update(Xml_node const & node)
 {
 	_model.update_from_xml(*this, node);
 
+	/*
+	 * Detect all shared interrupts
+	 */
+	enum { MAX_IRQ = 1024 };
+	Bit_array<MAX_IRQ> detected_irqs, shared_irqs;
+	for_each([&] (Device const & device) {
+		device._irq_list.for_each([&] (Device::Irq const & irq) {
+
+			if (irq.type != Device::Irq::LEGACY)
+				return;
+
+			if (detected_irqs.get(irq.number, 1)) {
+				if (!shared_irqs.get(irq.number, 1))
+					shared_irqs.set(irq.number, 1);
+			} else
+				detected_irqs.set(irq.number, 1);
+		});
+	});
+
+	/*
+	 * Mark all shared interrupts in the devices
+	 */
+	for_each([&] (Device & device) {
+		device._irq_list.for_each([&] (Device::Irq & irq) {
+
+			if (irq.type != Device::Irq::LEGACY)
+				return;
+
+			if (shared_irqs.get(irq.number, 1))
+				irq.shared = true;
+		});
+	});
+
+	/*
+	 * Create shared interrupt objects
+	 */
+	for (unsigned i = 0; i < MAX_IRQ; i++) {
+		if (!shared_irqs.get(i, 1))
+			continue;
+		bool found = false;
+		_shared_irqs.for_each([&] (Shared_interrupt & sirq) {
+			if (sirq.number() == i) found = true; });
+		if (!found)
+			new (_heap) Shared_interrupt(_shared_irqs, _env, i);
+	}
+
 	/*
 	 * Iterate over all devices and apply PCI quirks if necessary
 	 */

repos/os/src/drivers/platform/device.h

@@ -24,6 +24,7 @@
 #include <util/reconstructible.h>
 #include <util/xml_generator.h>
 
+#include <shared_irq.h>
 #include <clock.h>
 #include <reset.h>
 #include <power.h>
@@ -98,6 +99,7 @@ class Driver::Device : private List_model<Device>::Element
 			Type                  type     { LEGACY                          };
 			Irq_session::Polarity polarity { Irq_session::POLARITY_UNCHANGED };
 			Irq_session::Trigger  mode     { Irq_session::TRIGGER_UNCHANGED  };
+			bool                  shared   { false                           };
 
 			Irq(unsigned number) : number(number) {}
 		};
@@ -222,7 +224,8 @@ class Driver::Device : private List_model<Device>::Element
 		{
 			unsigned idx = 0;
 			_irq_list.for_each([&] (Irq const & irq) {
-				fn(idx++, irq.number, irq.type, irq.polarity, irq.mode); });
+				fn(idx++, irq.number, irq.type, irq.polarity,
+				   irq.mode, irq.shared); });
 		}
 
 		template <typename FN> void for_each_io_mem(FN const & fn) const
@@ -308,13 +311,14 @@ class Driver::Device_model :
 {
 	private:
 
-		Env                & _env;
-		Heap               & _heap;
-		Device_reporter    & _reporter;
-		List_model<Device>   _model  { };
-		Clocks               _clocks { };
-		Resets               _resets { };
-		Powers               _powers { };
+		Env                      & _env;
+		Heap                     & _heap;
+		Device_reporter          & _reporter;
+		List_model<Device>         _model  { };
+		Registry<Shared_interrupt> _shared_irqs { };
+		Clocks                     _clocks { };
+		Resets                     _resets { };
+		Powers                     _powers { };
 
 	public:
 
@@ -336,6 +340,13 @@ class Driver::Device_model :
 		template <typename FN>
 		void for_each(FN const & fn) const { _model.for_each(fn); }
 
+		template <typename FN>
+		void with_shared_irq(unsigned number, FN const & fn)
+		{
+			_shared_irqs.for_each([&] (Shared_interrupt & sirq) {
+				if (sirq.number() == number) fn(sirq); });
+		}
+
 
 		/***********************
 		 ** Update_policy API **

repos/os/src/drivers/platform/device_component.cc

@@ -15,6 +15,7 @@
 #include <device_component.h>
 #include <pci.h>
 #include <session_component.h>
+#include <shared_irq.h>
 
 using Driver::Device_component;
 
@@ -80,7 +81,7 @@ Genode::Irq_session_capability Device_component::irq(unsigned idx)
 		if (irq.idx != idx)
 			return;
 
-		if (!irq.irq.constructed()) {
+		if (!irq.shared && !irq.irq.constructed()) {
 			addr_t pci_cfg_addr = 0;
 			if (irq.type != Device::Irq::LEGACY) {
 				if (_pci_config.constructed()) pci_cfg_addr = _pci_config->addr;
@@ -94,7 +95,14 @@ Genode::Irq_session_capability Device_component::irq(unsigned idx)
 				pci_msi_enable(_env, pci_cfg_addr, info);
 		}
 
-		cap = irq.irq->cap();
+		if (irq.shared && !irq.sirq.constructed())
+			_device_model.with_shared_irq(irq.number,
+			                              [&] (Shared_interrupt & sirq) {
+				irq.sirq.construct(sirq, irq.mode, irq.polarity);
+				_env.ep().rpc_ep().manage(&*irq.sirq);
+			});
+
+		cap = irq.shared ? irq.sirq->cap() : irq.irq->cap();
 	});
 
 	return cap;
@@ -124,10 +132,12 @@ Genode::Io_port_session_capability Device_component::io_port_range(unsigned idx)
 Device_component::Device_component(Registry<Device_component> & registry,
                                    Env                        & env,
                                    Driver::Session_component  & session,
+                                   Driver::Device_model       & model,
                                    Driver::Device             & device)
 :
 	_env(env),
 	_session(session),
+	_device_model(model),
 	_device(device.name()),
 	_reg_elem(registry, *this)
 {
@@ -150,13 +160,15 @@ Device_component::Device_component(Registry<Device_component> & registry,
 		                         unsigned              nr,
 		                         Device::Irq::Type     type,
 		                         Irq_session::Polarity polarity,
-		                         Irq_session::Trigger  mode)
+		                         Irq_session::Trigger  mode,
+		                         bool                  shared)
 		{
 			session.ram_quota_guard().withdraw(Ram_quota{Irq_session::RAM_QUOTA});
 			_ram_quota += Irq_session::RAM_QUOTA;
 			session.cap_quota_guard().withdraw(Cap_quota{Irq_session::CAP_QUOTA});
 			_cap_quota += Irq_session::CAP_QUOTA;
-			new (session.heap()) Irq(_irq_registry, idx, nr, type, polarity, mode);
+			new (session.heap()) Irq(_irq_registry, idx, nr, type, polarity,
+			                         mode, shared);
 		});
 
 		device.for_each_io_mem([&] (unsigned idx, Range range,

repos/os/src/drivers/platform/device_component.h

@@ -38,23 +38,26 @@ class Driver::Device_component : public Rpc_object<Platform::Device_interface,
 
 		struct Irq : Registry<Irq>::Element
 		{
-			unsigned                      idx;
-			unsigned                      number;
-			Device::Irq::Type             type;
-			Irq_session::Polarity         polarity;
-			Irq_session::Trigger          mode;
-			Constructible<Irq_connection> irq {};
+			unsigned                                idx;
+			unsigned                                number;
+			Device::Irq::Type                       type;
+			Irq_session::Polarity                   polarity;
+			Irq_session::Trigger                    mode;
+			bool                                    shared;
+			Constructible<Irq_connection>           irq {};
+			Constructible<Shared_interrupt_session> sirq {};
 
 			Irq(Registry<Irq>       & registry,
 			    unsigned              idx,
 			    unsigned              number,
 			    Device::Irq::Type     type,
 			    Irq_session::Polarity polarity,
-			    Irq_session::Trigger  mode)
+			    Irq_session::Trigger  mode,
+			    bool                  shared)
 			:
 				Registry<Irq>::Element(registry, *this),
 				idx(idx), number(number), type(type),
-				polarity(polarity), mode(mode) {}
+				polarity(polarity), mode(mode), shared(shared) {}
 		};
 
 		struct Io_mem : Registry<Io_mem>::Element
@@ -99,6 +102,7 @@ class Driver::Device_component : public Rpc_object<Platform::Device_interface,
 		Device_component(Registry<Device_component> & registry,
 		                 Env                        & env,
 		                 Session_component          & session,
+		                 Device_model               & model,
 		                 Driver::Device             & device);
 		~Device_component();
 
@@ -118,6 +122,7 @@ class Driver::Device_component : public Rpc_object<Platform::Device_interface,
 
 		Env                               & _env;
 		Session_component                 & _session;
+		Device_model                      & _device_model;
 		Driver::Device::Name const          _device;
 		size_t                              _cap_quota { 0 };
 		size_t                              _ram_quota { 0 };

repos/os/src/drivers/platform/session_component.cc

@@ -24,7 +24,7 @@ Genode::Capability<Platform::Device_interface>
 Session_component::_acquire(Device & device)
 {
 	Device_component * dc = new (heap())
-		Device_component(_device_registry, _env, *this, device);
+		Device_component(_device_registry, _env, *this, _devices, device);
 	device.acquire(*this);
 	return _env.ep().rpc_ep().manage(dc);
 };

repos/os/src/drivers/platform/shared_irq.cc

@@ -0,0 +1,65 @@
+/*
+ * \brief  Platform driver - shared interrupts
+ * \author Stefan Kalkowski
+ * \date   2022-09-27
+ */
+
+/*
+ * Copyright (C) 2022 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#include <shared_irq.h>
+
+using Driver::Shared_interrupt;
+using Driver::Shared_interrupt_session;
+
+
+void Shared_interrupt::_handle()
+{
+	_sessions.for_each([&] (Shared_interrupt_session & session) {
+		session.signal(); });
+}
+
+
+void Shared_interrupt::enable(Irq_session::Trigger  mode,
+                              Irq_session::Polarity polarity)
+{
+	if (!_irq.constructed()) {
+		_irq.construct(_env, _number, mode, polarity);
+		_irq->sigh(_handler);
+	}
+}
+
+
+void Shared_interrupt::disable()
+{
+	unsigned session_count = 0;
+	_sessions.for_each([&] (Shared_interrupt_session &) {
+		session_count++; });
+
+	/* if it is the last session, close the upstream connection */
+	if (session_count <= 1)
+		_irq.destruct();
+}
+
+
+void Shared_interrupt::ack()
+{
+	unsigned outstanding = 0;
+	_sessions.for_each([&] (Shared_interrupt_session & session) {
+		if (session.outstanding()) outstanding++; });
+	if (!outstanding) _irq->ack_irq();
+}
+
+
+void Shared_interrupt_session::signal()
+{
+	if (!_cap.valid())
+		return;
+
+	_outstanding = true;
+	Signal_transmitter(_cap).submit(1);
+}

repos/os/src/drivers/platform/shared_irq.h

@@ -0,0 +1,110 @@
+/*
+ * \brief  Platform driver - shared interrupts
+ * \author Stefan Kalkowski
+ * \date   2022-09-27
+ */
+
+/*
+ * Copyright (C) 2022 Genode Labs GmbH
+ *
+ * This file is part of the Genode OS framework, which is distributed
+ * under the terms of the GNU Affero General Public License version 3.
+ */
+
+#ifndef _SRC__DRIVERS__PLATFORM__SHARED_IRQ_H_
+#define _SRC__DRIVERS__PLATFORM__SHARED_IRQ_H_
+
+#include <base/registry.h>
+#include <base/rpc_server.h>
+#include <irq_session/connection.h>
+
+namespace Driver {
+	using namespace Genode;
+
+	class Shared_interrupt;
+	class Shared_interrupt_session;
+}
+
+
+class Driver::Shared_interrupt :
+	private Registry<Shared_interrupt>::Element
+{
+	private:
+
+		Env                               & _env;
+		unsigned                            _number;
+		Io_signal_handler<Shared_interrupt> _handler;
+		Constructible<Irq_connection>       _irq {};
+		Registry<Shared_interrupt_session>  _sessions {};
+
+		void _handle();
+
+		friend class Shared_interrupt_session;
+
+	public:
+
+		Shared_interrupt(Registry<Shared_interrupt> & registry,
+		                 Env                        & env,
+		                 unsigned                     number)
+		:
+			Registry<Shared_interrupt>::Element(registry, *this),
+			_env(env),
+			_number(number),
+			_handler(env.ep(), *this, &Shared_interrupt::_handle) {}
+
+		unsigned number() const { return _number; }
+
+		void enable(Irq_session::Trigger  mode,
+		            Irq_session::Polarity polarity);
+		void disable();
+		void ack();
+};
+
+
+class Driver::Shared_interrupt_session :
+	public  Rpc_object<Irq_session, Shared_interrupt_session>,
+	private Registry<Shared_interrupt_session>::Element
+{
+	private:
+
+		Shared_interrupt        & _sirq;
+		Signal_context_capability _cap {};
+		bool                      _outstanding { true };
+
+	public:
+
+		Shared_interrupt_session(Shared_interrupt    & sirq,
+		                         Irq_session::Trigger  mode,
+		                         Irq_session::Polarity polarity)
+		:
+			Registry<Shared_interrupt_session>::Element(sirq._sessions, *this),
+			_sirq(sirq)
+		{
+			sirq.enable(mode, polarity);
+		}
+
+		~Shared_interrupt_session() { _sirq.disable(); }
+
+		bool outstanding() { return _outstanding; }
+		void signal();
+
+
+		/***************************
+		 ** Irq session interface **
+		 ***************************/
+
+		void ack_irq() override
+		{
+			_outstanding = false;
+			_sirq.ack();
+		}
+
+		void sigh(Signal_context_capability cap) override { _cap = cap; }
+
+		Info info() override
+		{
+			return { .type = Info::Type::INVALID, .address = 0, .value = 0 };
+		}
+};
+
+#endif /* _SRC__DRIVERS__PLATFORM__SHARED_IRQ_H_ */

repos/os/src/drivers/platform/target.inc

@@ -6,6 +6,7 @@ SRC_CC  += main.cc
 SRC_CC  += pci.cc
 SRC_CC  += root.cc
 SRC_CC  += session_component.cc
+SRC_CC  += shared_irq.cc
 
 GENERIC_DIR := $(dir $(call select_from_repositories,src/drivers/platform/target.inc))