From 2c7c7767fc93141065f693ff2aafab9fef338639 Mon Sep 17 00:00:00 2001
From: Norman Feske <norman.feske@genode-labs.com>
Date: Mon, 29 Mar 2021 17:40:17 +0200
Subject: [PATCH] platform_drv: respond to <system state="reset"/>

If 'system="yes"' is specified in the <config>, the platform driver now
monitors the content of the system ROM. Should the value become "reset",
a reset is triggered using information obtained from the ACPI driver.

Related to issue #2726
---
 .../os/src/drivers/platform/spec/x86/main.cc  | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/repos/os/src/drivers/platform/spec/x86/main.cc b/repos/os/src/drivers/platform/spec/x86/main.cc
index 85a33f8509..cc7f6b3cb0 100644
--- a/repos/os/src/drivers/platform/spec/x86/main.cc
+++ b/repos/os/src/drivers/platform/spec/x86/main.cc
@@ -54,6 +54,8 @@ struct Platform::Main
 	bool const _acpi_platform;
 	bool _acpi_ready    = false;
 
+	void _attempt_acpi_reset();
+
 	void acpi_update()
 	{
 		if (!root.constructed()) {
@@ -114,6 +116,19 @@ struct Platform::Main
 		if (!root_cap.valid())
 			acpi_update();
 
+		bool const system_state_was_constructed = system_state.constructed();
+
+		system_state.conditional(_config.xml().attribute_value("system", false),
+		                         _env, "system");
+
+		if (system_state.constructed() && !system_state_was_constructed)
+			system_state->sigh(_config_handler);
+
+		if (system_state.constructed()) {
+			system_state->update();
+			if (system_state->xml().attribute_value("state", String<16>()) == "reset")
+				_attempt_acpi_reset();
+		}
 
 		if (root.constructed()) {
 			root->generate_pci_report();
@@ -154,13 +169,40 @@ struct Platform::Main
 		/* wait for the first valid acpi report */
 		acpi_rom.construct(env, "acpi");
 		acpi_rom->sigh(_acpi_report);
+
 		/* check if already valid */
+		config_update();
 		acpi_update();
 		system_update();
 	}
 };
 
 
+void Platform::Main::_attempt_acpi_reset()
+{
+	using namespace Genode;
+
+	if (!acpi_rom.constructed())
+		return;
+
+	acpi_rom->xml().with_sub_node("reset", [&] (Xml_node reset) {
+
+		uint16_t const io_port = reset.attribute_value("io_port", (uint16_t)0);
+		uint8_t  const value   = reset.attribute_value("value",   (uint8_t)0);
+
+		log("trigger reset by writing value ", value, " to I/O port ", Hex(io_port));
+
+		try {
+			Io_port_connection reset_port { _env, io_port, 1 };
+			reset_port.outb(io_port, value);
+		}
+		catch (...) {
+			error("unable to access reset I/O port ", Hex(io_port));
+		}
+	});
+}
+
+
 void Component::construct(Genode::Env &env)
 {
 	/* XXX execute constructors of global statics */