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73 lines
2.1 KiB
C
73 lines
2.1 KiB
C
/*
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* Copyright (C) 2014 René Kijewski <rene.kijewski@fu-berlin.de>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @ingroup x86-irq
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* @{
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*
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* @file
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* @brief Configuration and interrupt handling for the Programmable Interval Timer (PIT).
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*
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* @author René Kijewski <rene.kijewski@fu-berlin.de>
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*
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* @}
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*/
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#include "x86_interrupts.h"
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#include "x86_pit.h"
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#include "x86_ports.h"
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#include "cpu.h"
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#include "irq.h"
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#include <stdio.h>
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void x86_init_pit(void)
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{
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puts("PIT initialized");
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}
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uint16_t x86_pit_read(unsigned channel)
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{
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unsigned old_flags = irq_disable();
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outb(PIT_COMMAND_PORT, (channel - 1) << 6 | PIT_ACCESS_MODE_LATCH_COUNT);
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uint16_t lohi = inb(PIT_CHANNEL_0_PORT + channel - 1);
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lohi += inb(PIT_CHANNEL_0_PORT + channel - 1) << 8;
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irq_restore(old_flags);
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return lohi;
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}
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void x86_pit_set2(unsigned channel, unsigned mode, uint16_t max)
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{
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unsigned old_flags = irq_disable();
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outb(PIT_COMMAND_PORT, ((channel - 1) << 6) | mode | PIT_ACCESS_MODE_LO_HI);
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outb(PIT_CHANNEL_0_PORT + channel - 1, max & 0xff);
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outb(PIT_CHANNEL_0_PORT + channel - 1, max >> 8);
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irq_restore(old_flags);
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}
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bool x86_pit_set(unsigned channel, unsigned mode, unsigned hz)
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{
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if (PIT_MIN_HZ > hz || hz > PIT_MAX_HZ) {
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return false;
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}
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uint16_t max = PIT_MAX_HZ / hz;
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x86_pit_set2(channel, mode, max);
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return true;
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}
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