Imbus/xv6-riscv-kernel
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rename 8253pit.c to timer.c

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rsc 2007-08-28 04:40:58 +00:00
parent eae04163a7
commit 9e82bfb04c
5 changed files with 38 additions and 51 deletions
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45
8253pit.c
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@ -1,45 +0,0 @@
#include "types.h"
#include "defs.h"
#include "traps.h"
#include "x86.h"
// Register definitions for the Intel
// 8253/8254/82C54 Programmable Interval Timer (PIT).
#define IO_TIMER1 0x040 // 8253 Timer #1
#define IO_TIMER2 0x048 // 8253 Timer #2 (EISA only)
// Frequency of all three count-down timers; (TIMER_FREQ/freq) is the
// appropriate count to generate a frequency of freq hz.
#define TIMER_FREQ 1193182
#define TIMER_DIV(x) ((TIMER_FREQ+(x)/2)/(x))
#define TIMER_CNTR0 (IO_TIMER1 + 0) // timer 0 counter port
#define TIMER_CNTR1 (IO_TIMER1 + 1) // timer 1 counter port
#define TIMER_CNTR2 (IO_TIMER1 + 2) // timer 2 counter port
#define TIMER_MODE (IO_TIMER1 + 3) // timer mode port
#define TIMER_SEL0 0x00 // select counter 0
#define TIMER_SEL1 0x40 // select counter 1
#define TIMER_SEL2 0x80 // select counter 2
#define TIMER_INTTC 0x00 // mode 0, intr on terminal cnt
#define TIMER_ONESHOT 0x02 // mode 1, one shot
#define TIMER_RATEGEN 0x04 // mode 2, rate generator
#define TIMER_SQWAVE 0x06 // mode 3, square wave
#define TIMER_SWSTROBE 0x08 // mode 4, s/w triggered strobe
#define TIMER_HWSTROBE 0x0a // mode 5, h/w triggered strobe
#define TIMER_LATCH 0x00 // latch counter for reading
#define TIMER_LSB 0x10 // r/w counter LSB
#define TIMER_MSB 0x20 // r/w counter MSB
#define TIMER_16BIT 0x30 // r/w counter 16 bits, LSB first
#define TIMER_BCD 0x01 // count in BCD
void
pit8253_timerinit(void)
{
// initialize 8253 clock to interrupt 100 times/sec
outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
outb(IO_TIMER1, TIMER_DIV(100) % 256);
outb(IO_TIMER1, TIMER_DIV(100) / 256);
irq_enable(IRQ_TIMER);
}

6
defs.h
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@ -7,9 +7,6 @@ struct proc;
struct spinlock;
struct stat;
// 8253pit.c
void pit8253_timerinit(void);
// bio.c
void binit(void);
struct buf* bread(uint, uint);
@ -140,6 +137,9 @@ int fetchint(struct proc*, uint, int*);
int fetchstr(struct proc*, uint, char**);
void syscall(void);
// timer.c
void timer_init(void);
// trap.c
void idtinit(void);
extern int ticks;

4
main.c
View file

@ -46,7 +46,7 @@ main(void)
ide_init(); // disk
bootothers(); // boot other CPUs
if(!ismp)
pit8253_timerinit(); // uniprocessor timer
timer_init(); // uniprocessor timer
userinit(); // first user process
// enable interrupts on this processor.
@ -74,7 +74,7 @@ mpmain(void)
scheduler();
}
void
static void
bootothers(void)
{
extern uchar _binary_bootother_start[], _binary_bootother_size[];

2
runoff.list
View file

@ -64,7 +64,7 @@ picirq.c
kbd.h
kbd.c
console.c
8253pit.c
timer.c
# user-level
usys.S

32
timer.c Normal file
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@ -0,0 +1,32 @@
// Intel 8253/8254/82C54 Programmable Interval Timer (PIT).
// Only used on uniprocessors;
// SMP machines use the local APIC timer.
#include "types.h"
#include "defs.h"
#include "traps.h"
#include "x86.h"
#define IO_TIMER1 0x040 // 8253 Timer #1
// Frequency of all three count-down timers;
// (TIMER_FREQ/freq) is the appropriate count
// to generate a frequency of freq Hz.
#define TIMER_FREQ 1193182
#define TIMER_DIV(x) ((TIMER_FREQ+(x)/2)/(x))
#define TIMER_MODE (IO_TIMER1 + 3) // timer mode port
#define TIMER_SEL0 0x00 // select counter 0
#define TIMER_RATEGEN 0x04 // mode 2, rate generator
#define TIMER_16BIT 0x30 // r/w counter 16 bits, LSB first
void
timer_init(void)
{
// Interrupt 100 times/sec.
outb(TIMER_MODE, TIMER_SEL0 | TIMER_RATEGEN | TIMER_16BIT);
outb(IO_TIMER1, TIMER_DIV(100) % 256);
outb(IO_TIMER1, TIMER_DIV(100) / 256);
irq_enable(IRQ_TIMER);
}