Move timer from os to base repository

Since the timer and timeout handling is part of the base library (the
dynamic linker), it belongs to the base repository.

Besides moving the timer and its related infrastructure (alarm, timeout
libs, tests) to the base repository, this patch also moves the timer
from the 'drivers' subdirectory directly to 'src' and disamibuates the
timer's build locations for the various kernels. Otherwise the different
timer implementations could interfere with each other when using one
build directory with multiple kernels.

Note that this patch changes the include paths for the former os/timer,
os/alarm.h, os/duration.h, and os/timed_semaphore.h to base/.

Issue #3101

repos/base-nova/src/timer/nova/target.mk

@@ -0,0 +1,5 @@
+TARGET   = nova_timer_drv
+INC_DIR += $(PRG_DIR)
+SRC_CC  += time_source.cc
+
+include $(call select_from_repositories,src/timer/target.inc)

repos/base-nova/src/timer/nova/time_source.cc

@@ -0,0 +1,81 @@
+/*
+ * \brief  Time source using Nova timed semaphore down
+ * \author Alexander Boettcher
+ * \author Martin Stein
+ * \date   2014-06-24
+ */
+
+/*
+ * Copyright (C) 2014-2017 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.
+ */
+
+/* Genode includes */
+#include <base/attached_rom_dataspace.h>
+
+/* NOVA includes */
+#include <nova/native_thread.h>
+
+/* local includes */
+#include <time_source.h>
+
+using namespace Genode;
+using namespace Nova;
+
+
+Timer::Time_source::Time_source(Env &env) : Threaded_time_source(env)
+{
+	/* read out the tsc frequency once */
+	Attached_rom_dataspace const platform_info { env, "platform_info" };
+	Xml_node const hardware = platform_info.xml().sub_node("hardware");
+	hardware.sub_node("tsc").attribute("freq_khz").value(&_tsc_khz);
+
+	start();
+}
+
+
+void Timer::Time_source::schedule_timeout(Microseconds     duration,
+                                          Timeout_handler &handler)
+{
+	Threaded_time_source::handler(handler);
+
+	/* check whether to cancel last timeout */
+	if (duration.value == 0 && _sem != ~0UL) {
+		uint8_t res = Nova::sm_ctrl(_sem, Nova::SEMAPHORE_UP);
+		if (res != Nova::NOVA_OK)
+			nova_die();
+	}
+	/* remember timeout to be set during wait_for_timeout call */
+	_timeout_us = duration.value;
+}
+
+
+void Timer::Time_source::_wait_for_irq()
+{
+	if (_sem == ~0UL) {
+		_sem = Thread::native_thread().exc_pt_sel + SM_SEL_EC; }
+
+	addr_t sem = _sem;
+
+	/* calculate absolute timeout */
+	Trace::Timestamp now   = Trace::timestamp();
+	Trace::Timestamp us_64 = _timeout_us;
+
+	if (_timeout_us == max_timeout().value) {
+
+		/* tsc_absolute == 0 means blocking without timeout */
+		uint8_t res = sm_ctrl(sem, SEMAPHORE_DOWN, 0);
+		if (res != Nova::NOVA_OK && res != Nova::NOVA_TIMEOUT) {
+			nova_die(); }
+
+	} else {
+
+		/* block until timeout fires or it gets canceled */
+		unsigned long long tsc_absolute = now + us_64 * (_tsc_khz / TSC_FACTOR);
+		uint8_t res = sm_ctrl(sem, SEMAPHORE_DOWN, tsc_absolute);
+		if (res != Nova::NOVA_OK && res != Nova::NOVA_TIMEOUT) {
+			nova_die(); }
+	}
+}

repos/base-nova/src/timer/nova/time_source.h

@@ -0,0 +1,88 @@
+/*
+ * \brief  Time source using Nova timed semaphore down
+ * \author Alexander Boettcher
+ * \author Martin Stein
+ * \date   2014-06-24
+ */
+
+/*
+ * Copyright (C) 2014-2017 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 _TIME_SOURCE_H_
+#define _TIME_SOURCE_H_
+
+/* Genode includes */
+#include <trace/timestamp.h>
+
+/* local includes */
+#include <threaded_time_source.h>
+
+namespace Timer { class Time_source; }
+
+
+class Timer::Time_source : public Threaded_time_source
+{
+	private:
+
+		Genode::addr_t           _sem        { ~0UL };
+		unsigned long            _timeout_us { 0 };
+		unsigned long            _tsc_khz    { 0 };
+		Duration                 _curr_time  { Microseconds(0) };
+		Genode::Trace::Timestamp _tsc_start  { Genode::Trace::timestamp() };
+		Genode::Trace::Timestamp _tsc_last   { _tsc_start };
+
+		/* 1 / ((us / (1000 * 1000)) * (tsc_khz * 1000)) */
+		enum { TSC_FACTOR = 1000ULL };
+
+		inline Genode::uint64_t _tsc_to_us(Genode::uint64_t tsc) const
+		{
+			return (tsc) / (_tsc_khz / TSC_FACTOR);
+		}
+
+
+		/**************************
+		 ** Threaded_time_source **
+		 **************************/
+
+		void _wait_for_irq();
+
+	public:
+
+		Time_source(Genode::Env &env);
+
+
+		/*************************
+		 ** Genode::Time_source **
+		 *************************/
+
+		void schedule_timeout(Microseconds duration,
+		                      Timeout_handler &handler) override;
+
+		Microseconds max_timeout() const override
+		{
+			unsigned long long const max_us_ull = _tsc_to_us(~0ULL);
+			return max_us_ull > ~0UL ? Microseconds(~0UL) : Microseconds(max_us_ull);
+		}
+
+		Duration curr_time() override
+		{
+			using namespace Genode::Trace;
+
+			Timestamp    const curr_tsc = timestamp();
+			Microseconds const diff(_tsc_to_us(curr_tsc - _tsc_last));
+
+			/* update in irq context or if update rate is below 4000 irq/s */
+			if (_irq || diff.value > 250) {
+				_curr_time.add(diff);
+				_tsc_last = curr_tsc;
+			}
+
+			return _curr_time;
+		}
+};
+
+#endif /* _TIME_SOURCE_H_ */