82 lines
2.0 KiB
C
82 lines
2.0 KiB
C
/*
|
|
* arch/sh/boards/dreamcast/rtc.c
|
|
*
|
|
* Dreamcast AICA RTC routines.
|
|
*
|
|
* Copyright (c) 2001, 2002 M. R. Brown <mrbrown@0xd6.org>
|
|
* Copyright (c) 2002 Paul Mundt <lethal@chaoticdreams.org>
|
|
*
|
|
* Released under the terms of the GNU GPL v2.0.
|
|
*
|
|
*/
|
|
|
|
#include <linux/time.h>
|
|
#include <asm/rtc.h>
|
|
#include <asm/io.h>
|
|
|
|
/* The AICA RTC has an Epoch of 1/1/1950, so we must subtract 20 years (in
|
|
seconds) to get the standard Unix Epoch when getting the time, and add
|
|
20 years when setting the time. */
|
|
#define TWENTY_YEARS ((20 * 365LU + 5) * 86400)
|
|
|
|
/* The AICA RTC is represented by a 32-bit seconds counter stored in 2 16-bit
|
|
registers.*/
|
|
#define AICA_RTC_SECS_H 0xa0710000
|
|
#define AICA_RTC_SECS_L 0xa0710004
|
|
|
|
/**
|
|
* aica_rtc_gettimeofday - Get the time from the AICA RTC
|
|
* @ts: pointer to resulting timespec
|
|
*
|
|
* Grabs the current RTC seconds counter and adjusts it to the Unix Epoch.
|
|
*/
|
|
void aica_rtc_gettimeofday(struct timespec *ts)
|
|
{
|
|
unsigned long val1, val2;
|
|
|
|
do {
|
|
val1 = ((ctrl_inl(AICA_RTC_SECS_H) & 0xffff) << 16) |
|
|
(ctrl_inl(AICA_RTC_SECS_L) & 0xffff);
|
|
|
|
val2 = ((ctrl_inl(AICA_RTC_SECS_H) & 0xffff) << 16) |
|
|
(ctrl_inl(AICA_RTC_SECS_L) & 0xffff);
|
|
} while (val1 != val2);
|
|
|
|
ts->tv_sec = val1 - TWENTY_YEARS;
|
|
|
|
/* Can't get nanoseconds with just a seconds counter. */
|
|
ts->tv_nsec = 0;
|
|
}
|
|
|
|
/**
|
|
* aica_rtc_settimeofday - Set the AICA RTC to the current time
|
|
* @secs: contains the time_t to set
|
|
*
|
|
* Adjusts the given @tv to the AICA Epoch and sets the RTC seconds counter.
|
|
*/
|
|
int aica_rtc_settimeofday(const time_t secs)
|
|
{
|
|
unsigned long val1, val2;
|
|
unsigned long adj = secs + TWENTY_YEARS;
|
|
|
|
do {
|
|
ctrl_outl((adj & 0xffff0000) >> 16, AICA_RTC_SECS_H);
|
|
ctrl_outl((adj & 0xffff), AICA_RTC_SECS_L);
|
|
|
|
val1 = ((ctrl_inl(AICA_RTC_SECS_H) & 0xffff) << 16) |
|
|
(ctrl_inl(AICA_RTC_SECS_L) & 0xffff);
|
|
|
|
val2 = ((ctrl_inl(AICA_RTC_SECS_H) & 0xffff) << 16) |
|
|
(ctrl_inl(AICA_RTC_SECS_L) & 0xffff);
|
|
} while (val1 != val2);
|
|
|
|
return 0;
|
|
}
|
|
|
|
void aica_time_init(void)
|
|
{
|
|
rtc_get_time = aica_rtc_gettimeofday;
|
|
rtc_set_time = aica_rtc_settimeofday;
|
|
}
|
|
|