historical/m0-applesillicon.git/xnu-qemu-arm64-5.1.0/roms/openbios/drivers/timer.c
2024-01-16 11:20:27 -06:00

100 lines
2 KiB
C

/*
* OpenBIOS native timer driver
*
* (C) 2004 Stefan Reinauer
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* version 2
*
*/
#include "config.h"
#include "drivers/drivers.h"
#include "timer.h"
#include "asm/io.h"
#if defined(CONFIG_X86) || defined(CONFIG_AMD64)
void setup_timers(void)
{
/* nothing to do */
}
static void load_timer2(unsigned int ticks)
{
/* Set up the timer gate, turn off the speaker */
outb((inb(PPC_PORTB) & ~PPCB_SPKR) | PPCB_T2GATE, PPC_PORTB);
outb(TIMER2_SEL | WORD_ACCESS | MODE0 | BINARY_COUNT,
TIMER_MODE_PORT);
outb(ticks & 0xFF, TIMER2_PORT);
outb(ticks >> 8, TIMER2_PORT);
}
void udelay(unsigned int usecs)
{
load_timer2((usecs * TICKS_PER_MS) / 1000);
while ((inb(PPC_PORTB) & PPCB_T2OUT) == 0);
}
unsigned long currticks(void)
{
static unsigned long totticks = 0UL; /* High resolution */
unsigned long ticks = 0;
unsigned char portb = inb(PPC_PORTB);
/*
* Read the timer, and hope it hasn't wrapped around
* (call this again within 54ms), then restart it
*/
outb(TIMER2_SEL | LATCH_COUNT, TIMER_MODE_PORT);
ticks = inb(TIMER2_PORT);
ticks |= inb(TIMER2_PORT) << 8;
outb(TIMER2_SEL | WORD_ACCESS | MODE0 | BINARY_COUNT,
TIMER_MODE_PORT);
outb(0, TIMER2_PORT);
outb(0, TIMER2_PORT);
/*
* Check if the timer was running. If not,
* result is rubbish and need to start it
*/
if (portb & PPCB_T2GATE) {
totticks += (0x10000 - ticks);
} else {
/* Set up the timer gate, turn off the speaker */
outb((portb & ~PPCB_SPKR) | PPCB_T2GATE, PPC_PORTB);
}
return totticks / TICKS_PER_MS;
}
#endif
#ifdef CONFIG_PPC
void setup_timers(void)
{
/* nothing to do */
}
/*
* TODO: pass via lb table
*/
unsigned long timer_freq = 10000000 / 4;
void udelay(unsigned int usecs)
{
unsigned long ticksperusec = timer_freq / 1000000;
_wait_ticks(ticksperusec * usecs);
}
#endif
void ndelay(unsigned int nsecs)
{
udelay((nsecs + 999) / 1000);
}
void mdelay(unsigned int msecs)
{
udelay(msecs * 1000);
}