151 lines
4.6 KiB
C++
151 lines
4.6 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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x86-family/time.cpp
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Retrieving the current time.
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*******************************************************************************/
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#include <sys/types.h>
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#include <timespec.h>
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#include <sortix/timespec.h>
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#include <sortix/kernel/clock.h>
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#include <sortix/kernel/cpu.h>
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#include <sortix/kernel/interrupt.h>
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#include <sortix/kernel/ioport.h>
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#include <sortix/kernel/kernel.h>
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#include <sortix/kernel/process.h>
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#include <sortix/kernel/scheduler.h>
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#include <sortix/kernel/thread.h>
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#include <sortix/kernel/time.h>
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namespace Sortix {
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namespace Time {
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static uint16_t DivisorOfFrequency(long frequency)
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{
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// The value we send to the PIT is the value to divide it's input clock
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// (1193180 Hz) by, to get our required frequency. Note that the divisor
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// must be small enough to fit into 16 bits.
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return 1193180 / frequency;
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}
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static long FrequencyOfDivisor(uint16_t divisor)
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{
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return 1193180 / divisor;
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}
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static long RealFrequencyOfFrequency(long frequency)
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{
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return FrequencyOfDivisor(DivisorOfFrequency(frequency));
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}
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static struct timespec PeriodOfFrequency(long frequency)
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{
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long period_ns = 1000000000L / frequency;
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return timespec_make(0, period_ns);
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}
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static void RequestIRQ0(uint16_t divisor)
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{
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outport8(0x43, 0x36);
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outport8(0x40, divisor >> 0 & 0xFF);
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outport8(0x40, divisor >> 8 & 0xFF);
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}
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extern Clock* realtime_clock;
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extern Clock* uptime_clock;
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struct interrupt_handler timer_interrupt_registration;
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static struct timespec tick_period;
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static long tick_frequency;
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static uint16_t tick_divisor;
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static void OnIRQ0(struct interrupt_context* intctx, void* /*user*/)
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{
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OnTick(tick_period, !InUserspace(intctx));
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Scheduler::Switch(intctx);
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// TODO: There is a horrible bug that causes Sortix to only receive
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// one IRQ0 on my laptop, but it works in virtual machines. But
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// re-requesting an addtional time seems to work. Hacky and ugly.
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// TODO: Confirm whether this still happens and whether it is trigged by
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// another bug in my system.
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static bool did_ugly_irq0_hack = false;
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if ( !did_ugly_irq0_hack )
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RequestIRQ0(tick_divisor),
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did_ugly_irq0_hack = true;
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}
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void CPUInit()
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{
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// Estimate the rate that interrupts will be coming at.
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long desired_frequency = 100/*Hz*/;
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tick_frequency = RealFrequencyOfFrequency(desired_frequency);
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tick_divisor = DivisorOfFrequency(tick_frequency);
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tick_period = PeriodOfFrequency(tick_frequency);
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// Initialize the clocks on this system.
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realtime_clock->SetCallableFromInterrupts(true);
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uptime_clock->SetCallableFromInterrupts(true);
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struct timespec nul_time = timespec_nul();
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realtime_clock->Set(&nul_time, &tick_period);
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uptime_clock->Set(&nul_time, &tick_period);
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}
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void InitializeProcessClocks(Process* process)
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{
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struct timespec nul_time = timespec_nul();
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process->execute_clock.SetCallableFromInterrupts(true);
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process->execute_clock.Set(&nul_time, &tick_period);
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process->system_clock.SetCallableFromInterrupts(true);
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process->system_clock.Set(&nul_time, &tick_period);
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process->child_execute_clock.Set(&nul_time, &tick_period);
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process->child_execute_clock.SetCallableFromInterrupts(true);
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process->child_system_clock.Set(&nul_time, &tick_period);
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process->child_system_clock.SetCallableFromInterrupts(true);
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}
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void InitializeThreadClocks(Thread* thread)
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{
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struct timespec nul_time = timespec_nul();
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thread->execute_clock.SetCallableFromInterrupts(true);
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thread->execute_clock.Set(&nul_time, &tick_period);
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thread->system_clock.SetCallableFromInterrupts(true);
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thread->system_clock.Set(&nul_time, &tick_period);
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}
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void Start()
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{
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// Handle timer interrupts if they arrive.
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timer_interrupt_registration.handler = OnIRQ0;
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timer_interrupt_registration.context = 0;
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Interrupt::RegisterHandler(Interrupt::IRQ0, &timer_interrupt_registration);
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// Request a timer interrupt now that we can handle them safely.
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RequestIRQ0(tick_divisor);
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}
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} // namespace Time
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} // namespace Sortix
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