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/*
* linux/arch/i386/kernel/time.c
*
* 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 intel version
*
*/
#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/timex.h>
#include <linux/kernel_stat.h>
#include <linux/init.h>
#include <asm/segment.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/machdep.h>
#include <asm/prep_nvram.h>
#include <asm/mk48t59.h>
#include "time.h"
/*
* The motorola uses the m48t18 rtc (includes DS1643) whose registers
* are at a higher end of nvram (1ff8-1fff) than the ibm mc146818
* rtc (ds1386) which has regs at addr 0-d). The intel gets
* past this because the bios emulates the mc146818.
*
* Why in the world did they have to use different clocks?
*
* Right now things are hacked to check which machine we're on then
* use the appropriate macro. This is very very ugly and I should
* probably have a function that checks which machine we're on then
* does things correctly transparently or a function pointer which
* is setup at boot time to use the correct addresses.
* -- Cort
*/
/*
* Set the hardware clock. -- Cort
*/
__prep
int mc146818_set_rtc_time(unsigned long nowtime)
{
unsigned char save_control, save_freq_select;
struct rtc_time tm;
to_tm(nowtime, &tm);
/* tell the clock it's being set */
save_control = CMOS_READ(RTC_CONTROL);
CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
/* stop and reset prescaler */
save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
tm.tm_year = (tm.tm_year - 1900) % 100;
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);
}
CMOS_WRITE(tm.tm_sec, RTC_SECONDS);
CMOS_WRITE(tm.tm_min, RTC_MINUTES);
CMOS_WRITE(tm.tm_hour, RTC_HOURS);
CMOS_WRITE(tm.tm_mon, RTC_MONTH);
CMOS_WRITE(tm.tm_mday, RTC_DAY_OF_MONTH);
CMOS_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
*/
CMOS_WRITE(save_control, RTC_CONTROL);
CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
return 0;
}
__prep
unsigned long mc146818_get_rtc_time(void)
{
unsigned int year, mon, day, hour, min, sec;
int 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.
*/
/* read RTC exactly on falling edge of update flag */
for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
break;
for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */
if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
break;
do { /* Isn't this overkill ? UIP above should guarantee consistency */
sec = CMOS_READ(RTC_SECONDS);
min = CMOS_READ(RTC_MINUTES);
hour = CMOS_READ(RTC_HOURS);
day = CMOS_READ(RTC_DAY_OF_MONTH);
mon = CMOS_READ(RTC_MONTH);
year = CMOS_READ(RTC_YEAR);
} while (sec != CMOS_READ(RTC_SECONDS));
if (!(CMOS_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);
}
__prep
int mk48t59_set_rtc_time(unsigned long nowtime)
{
unsigned char save_control;
struct rtc_time tm;
to_tm(nowtime, &tm);
/* tell the clock it's being written */
save_control = ppc_md.nvram_read_val(MK48T59_RTC_CONTROLA);
ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA,
(save_control | MK48T59_RTC_CA_WRITE));
tm.tm_year = (tm.tm_year - 1900) % 100;
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);
ppc_md.nvram_write_val(MK48T59_RTC_SECONDS, tm.tm_sec);
ppc_md.nvram_write_val(MK48T59_RTC_MINUTES, tm.tm_min);
ppc_md.nvram_write_val(MK48T59_RTC_HOURS, tm.tm_hour);
ppc_md.nvram_write_val(MK48T59_RTC_MONTH, tm.tm_mon);
ppc_md.nvram_write_val(MK48T59_RTC_DAY_OF_MONTH, tm.tm_mday);
ppc_md.nvram_write_val(MK48T59_RTC_YEAR, tm.tm_year);
/* Turn off the write bit. */
ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control);
return 0;
}
__prep
unsigned long mk48t59_get_rtc_time(void)
{
unsigned char save_control;
unsigned int year, mon, day, hour, min, sec;
int i;
/* Make sure the time is not stopped. */
save_control = ppc_md.nvram_read_val(MK48T59_RTC_CONTROLB);
ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA,
(save_control & (~MK48T59_RTC_CB_STOP)));
/* Now make sure the read bit is off so the value will change. */
save_control = ppc_md.nvram_read_val(MK48T59_RTC_CONTROLA);
save_control &= ~MK48T59_RTC_CA_READ;
ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control);
/* Read the seconds value to see when it changes. */
sec = ppc_md.nvram_read_val(MK48T59_RTC_SECONDS);
/* Wait until the seconds value changes, then read the value. */
for (i = 0 ; i < 1000000 ; i++) { /* may take up to 1 second... */
if (ppc_md.nvram_read_val(MK48T59_RTC_SECONDS) != sec) {
break;
}
}
/* Set the register to read the value. */
ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA,
(save_control | MK48T59_RTC_CA_READ));
sec = ppc_md.nvram_read_val(MK48T59_RTC_SECONDS);
min = ppc_md.nvram_read_val(MK48T59_RTC_MINUTES);
hour = ppc_md.nvram_read_val(MK48T59_RTC_HOURS);
day = ppc_md.nvram_read_val(MK48T59_RTC_DAY_OF_MONTH);
mon = ppc_md.nvram_read_val(MK48T59_RTC_MONTH);
year = ppc_md.nvram_read_val(MK48T59_RTC_YEAR);
/* Let the time values change again. */
ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control);
BCD_TO_BIN(sec);
BCD_TO_BIN(min);
BCD_TO_BIN(hour);
BCD_TO_BIN(day);
BCD_TO_BIN(mon);
BCD_TO_BIN(year);
year = year + 1900;
if (year < 1970) {
year += 100;
}
return mktime(year, mon, day, hour, min, sec);
}
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