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/*
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
*
* Adapted for PowerPC (PReP) by Gary Thomas
* Modified by Cort Dougan (cort@cs.nmt.edu).
* Copied and modified from arch/i386/kernel/time.c
*
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/kernel_stat.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/bcd.h>
#include <asm/io.h>
#include <asm/nvram.h>
#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/time.h>
extern spinlock_t rtc_lock;
static int nvram_as1 = NVRAM_AS1;
static int nvram_as0 = NVRAM_AS0;
static int nvram_data = NVRAM_DATA;
long __init chrp_time_init(void)
{
struct device_node *rtcs;
int base;
rtcs = find_compatible_devices("rtc", "pnpPNP,b00");
if (rtcs == NULL)
rtcs = find_compatible_devices("rtc", "ds1385-rtc");
if (rtcs == NULL || rtcs->addrs == NULL)
return 0;
base = rtcs->addrs[0].address;
nvram_as1 = 0;
nvram_as0 = base;
nvram_data = base + 1;
return 0;
}
int chrp_cmos_clock_read(int addr)
{
if (nvram_as1 != 0)
outb(addr>>8, nvram_as1);
outb(addr, nvram_as0);
return (inb(nvram_data));
}
void chrp_cmos_clock_write(unsigned long val, int addr)
{
if (nvram_as1 != 0)
outb(addr>>8, nvram_as1);
outb(addr, nvram_as0);
outb(val, nvram_data);
return;
}
/*
* Set the hardware clock. -- Cort
*/
int chrp_set_rtc_time(unsigned long nowtime)
{
unsigned char save_control, save_freq_select;
struct rtc_time tm;
spin_lock(&rtc_lock);
to_tm(nowtime, &tm);
save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
tm.tm_year -= 1900;
if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
BIN_TO_BCD(tm.tm_sec);
BIN_TO_BCD(tm.tm_min);
BIN_TO_BCD(tm.tm_hour);
BIN_TO_BCD(tm.tm_mon);
BIN_TO_BCD(tm.tm_mday);
BIN_TO_BCD(tm.tm_year);
}
chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
/* The following flags have to be released exactly in this order,
* otherwise the DS12887 (popular MC146818A clone with integrated
* battery and quartz) will not reset the oscillator and will not
* update precisely 500 ms later. You won't find this mentioned in
* the Dallas Semiconductor data sheets, but who believes data
* sheets anyway ... -- Markus Kuhn
*/
chrp_cmos_clock_write(save_control, RTC_CONTROL);
chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
spin_unlock(&rtc_lock);
return 0;
}
unsigned long chrp_get_rtc_time(void)
{
unsigned int year, mon, day, hour, min, sec;
int uip, i;
/* The Linux interpretation of the CMOS clock register contents:
* When the Update-In-Progress (UIP) flag goes from 1 to 0, the
* RTC registers show the second which has precisely just started.
* Let's hope other operating systems interpret the RTC the same way.
*/
/* Since the UIP flag is set for about 2.2 ms and the clock
* is typically written with a precision of 1 jiffy, trying
* to obtain a precision better than a few milliseconds is
* an illusion. Only consistency is interesting, this also
* allows to use the routine for /dev/rtc without a potential
* 1 second kernel busy loop triggered by any reader of /dev/rtc.
*/
for ( i = 0; i<1000000; i++) {
uip = chrp_cmos_clock_read(RTC_FREQ_SELECT);
sec = chrp_cmos_clock_read(RTC_SECONDS);
min = chrp_cmos_clock_read(RTC_MINUTES);
hour = chrp_cmos_clock_read(RTC_HOURS);
day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
mon = chrp_cmos_clock_read(RTC_MONTH);
year = chrp_cmos_clock_read(RTC_YEAR);
uip |= chrp_cmos_clock_read(RTC_FREQ_SELECT);
if ((uip & RTC_UIP)==0) break;
}
if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
{
BCD_TO_BIN(sec);
BCD_TO_BIN(min);
BCD_TO_BIN(hour);
BCD_TO_BIN(day);
BCD_TO_BIN(mon);
BCD_TO_BIN(year);
}
if ((year += 1900) < 1970)
year += 100;
return mktime(year, mon, day, hour, min, sec);
}
/*
* Calibrate the decrementer frequency with the VIA timer 1.
*/
#define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */
/* VIA registers */
#define RS 0x200 /* skip between registers */
#define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */
#define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */
#define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */
#define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */
#define ACR (11*RS) /* Auxiliary control register */
#define IFR (13*RS) /* Interrupt flag register */
/* Bits in ACR */
#define T1MODE 0xc0 /* Timer 1 mode */
#define T1MODE_CONT 0x40 /* continuous interrupts */
/* Bits in IFR and IER */
#define T1_INT 0x40 /* Timer 1 interrupt */
static int __init chrp_via_calibrate_decr(void)
{
struct device_node *vias;
volatile unsigned char __iomem *via;
int count = VIA_TIMER_FREQ_6 / 100;
unsigned int dstart, dend;
vias = find_devices("via-cuda");
if (vias == 0)
vias = find_devices("via");
if (vias == 0 || vias->n_addrs == 0)
return 0;
via = ioremap(vias->addrs[0].address, vias->addrs[0].size);
/* set timer 1 for continuous interrupts */
out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT);
/* set the counter to a small value */
out_8(&via[T1CH], 2);
/* set the latch to `count' */
out_8(&via[T1LL], count);
out_8(&via[T1LH], count >> 8);
/* wait until it hits 0 */
while ((in_8(&via[IFR]) & T1_INT) == 0)
;
dstart = get_dec();
/* clear the interrupt & wait until it hits 0 again */
in_8(&via[T1CL]);
while ((in_8(&via[IFR]) & T1_INT) == 0)
;
dend = get_dec();
tb_ticks_per_jiffy = (dstart - dend) / ((6 * HZ)/100);
tb_to_us = mulhwu_scale_factor(dstart - dend, 60000);
printk(KERN_INFO "via_calibrate_decr: ticks per jiffy = %u (%u ticks)\n",
tb_ticks_per_jiffy, dstart - dend);
iounmap(via);
return 1;
}
void __init chrp_calibrate_decr(void)
{
struct device_node *cpu;
unsigned int freq, *fp;
if (chrp_via_calibrate_decr())
return;
/*
* The cpu node should have a timebase-frequency property
* to tell us the rate at which the decrementer counts.
*/
freq = 16666000; /* hardcoded default */
cpu = find_type_devices("cpu");
if (cpu != 0) {
fp = (unsigned int *)
get_property(cpu, "timebase-frequency", NULL);
if (fp != 0)
freq = *fp;
}
printk("time_init: decrementer frequency = %u.%.6u MHz\n",
freq/1000000, freq%1000000);
tb_ticks_per_jiffy = freq / HZ;
tb_to_us = mulhwu_scale_factor(freq, 1000000);
}
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