71188c92f9
- support of TSS-based task switching - add a mailbox template - suport of user level task - support of system calls git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@47 315a16e6-25f9-4109-90ae-ca3045a26c18
103 lines
2.4 KiB
C
103 lines
2.4 KiB
C
/*
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* Copyright 2010 Stefan Lankes, Chair for Operating Systems,
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* RWTH Aachen University
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of MetalSVM.
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*/
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#include <metalsvm/stdio.h>
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#include <metalsvm/string.h>
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#include <metalsvm/tasks.h>
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#include <metalsvm/time.h>
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#include <metalsvm/processor.h>
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#include <asm/irq.h>
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#include <asm/irqflags.h>
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#include <asm/vga.h>
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/*
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* This will keep track of how many ticks that the system
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* has been running for
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*/
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static volatile uint64_t timer_ticks = 0;
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static unsigned int curr_timer_freq = 18;
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/*
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* Handles the timer. In this case, it's very simple: We
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* increment the 'timer_ticks' variable every time the
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* timer fires.
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*/
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static void timer_handler(struct state *s)
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{
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/* Increment our 'tick counter' */
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timer_ticks++;
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/*
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* Every TIMER_FREQ clocks (approximately 1 second), we will
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* display a message on the screen
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*/
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if (timer_ticks % TIMER_FREQ == 0) {
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vga_puts("One second has passed\n");
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}
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}
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/*
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* This will continuously loop until the given time has
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* been reached
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*/
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void timer_wait(unsigned int ticks)
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{
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uint64_t eticks = timer_ticks + ticks;
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while (timer_ticks < eticks)
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reschedule();
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}
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/*
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* Sets up the system clock by installing the timer handler
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* into IRQ0
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*/
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int timer_init(void)
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{
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/* Installs 'timer_handler' to IRQ0 */
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irq_install_handler(0, timer_handler);
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return 0;
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}
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#define LATCH ((CLOCK_TICK_RATE + TIMER_FREQ/2) / TIMER_FREQ)
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int timer_set_frequency(unsigned int freq)
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{
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irq_disable();
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/* set the timer frequency */
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outportb(0x43, 0x34);
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udelay(10);
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outportb(0x40, LATCH & 0xFF); /* low byte */
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udelay(10);
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outportb(0x40, LATCH >> 8); /* high byte */
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curr_timer_freq = freq;
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irq_enable();
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return 0;
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}
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unsigned int timer_get_frequency(void)
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{
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return curr_timer_freq;
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}
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