[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / mn10300 / kernel / rtc.c

/* MN10300 RTC management
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/mc146818rtc.h>
#include <linux/bcd.h>
#include <linux/timex.h>
#include <asm/rtc-regs.h>
#include <asm/rtc.h>

DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);

/* last time the RTC got updated */
static long last_rtc_update;

/* time for RTC to update itself in ioclks */
static unsigned long mn10300_rtc_update_period;

void read_persistent_clock(struct timespec *ts)
{
	struct rtc_time tm;

	get_rtc_time(&tm);

	ts->tv_sec = mktime(tm.tm_year, tm.tm_mon, tm.tm_mday,
		      tm.tm_hour, tm.tm_min, tm.tm_sec);
	ts->tv_nsec = 0;
}

/*
 * In order to set the CMOS clock precisely, set_rtc_mmss has to be called 500
 * ms after the second nowtime has started, because when nowtime is written
 * into the registers of the CMOS clock, it will jump to the next second
 * precisely 500 ms later.  Check the Motorola MC146818A or Dallas DS12887 data
 * sheet for details.
 *
 * BUG: This routine does not handle hour overflow properly; it just
 *      sets the minutes. Usually you'll only notice that after reboot!
 */
static int set_rtc_mmss(unsigned long nowtime)
{
	unsigned char save_control, save_freq_select;
	int retval = 0;
	int real_seconds, real_minutes, cmos_minutes;

	/* gets recalled with irq locally disabled */
	spin_lock(&rtc_lock);
	save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being
						* set */
	CMOS_WRITE(save_control | RTC_SET, RTC_CONTROL);

	save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset
							* prescaler */
	CMOS_WRITE(save_freq_select | RTC_DIV_RESET2, RTC_FREQ_SELECT);

	cmos_minutes = CMOS_READ(RTC_MINUTES);
	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
		cmos_minutes = bcd2bin(cmos_minutes);

	/*
	 * since we're only adjusting minutes and seconds,
	 * don't interfere with hour overflow. This avoids
	 * messing with unknown time zones but requires your
	 * RTC not to be off by more than 15 minutes
	 */
	real_seconds = nowtime % 60;
	real_minutes = nowtime / 60;
	if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
		/* correct for half hour time zone */
		real_minutes += 30;
	real_minutes %= 60;

	if (abs(real_minutes - cmos_minutes) < 30) {
		if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
			real_seconds = bin2bcd(real_seconds);
			real_minutes = bin2bcd(real_minutes);
		}
		CMOS_WRITE(real_seconds, RTC_SECONDS);
		CMOS_WRITE(real_minutes, RTC_MINUTES);
	} else {
		printk(KERN_WARNING
		       "set_rtc_mmss: can't update from %d to %d\n",
		       cmos_minutes, real_minutes);
		retval = -1;
	}

	/* 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);
	spin_unlock(&rtc_lock);

	return retval;
}

int update_persistent_clock(struct timespec now)
{
	return set_rtc_mms(now.tv_sec);
}

/*
 * calibrate the TSC clock against the RTC
 */
void __init calibrate_clock(void)
{
	unsigned long count0, counth, count1;
	unsigned char status;

	/* make sure the RTC is running and is set to operate in 24hr mode */
	status = RTSRC;
	RTCRB |= RTCRB_SET;
	RTCRB |= RTCRB_TM_24HR;
	RTCRA |= RTCRA_DVR;
	RTCRA &= ~RTCRA_DVR;
	RTCRB &= ~RTCRB_SET;

	/* work out the clock speed by counting clock cycles between ends of
	 * the RTC update cycle - track the RTC through one complete update
	 * cycle (1 second)
	 */
	startup_timestamp_counter();

	while (!(RTCRA & RTCRA_UIP)) {}
	while ((RTCRA & RTCRA_UIP)) {}

	count0 = TMTSCBC;

	while (!(RTCRA & RTCRA_UIP)) {}

	counth = TMTSCBC;

	while ((RTCRA & RTCRA_UIP)) {}

	count1 = TMTSCBC;

	shutdown_timestamp_counter();

	MN10300_TSCCLK = count0 - count1; /* the timers count down */
	mn10300_rtc_update_period = counth - count1;
	MN10300_TSC_PER_HZ = MN10300_TSCCLK / HZ;
}
Commit	Line	Data
b920de1b DH	1	/* MN10300 RTC management
	2	*
	3	* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public Licence
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the Licence, or (at your option) any later version.
	10	*/
	11	#include <linux/kernel.h>
	12	#include <linux/module.h>
	13	#include <linux/init.h>
	14	#include <linux/mc146818rtc.h>
	15	#include <linux/bcd.h>
	16	#include <linux/timex.h>
	17	#include <asm/rtc-regs.h>
	18	#include <asm/rtc.h>
	19
	20	DEFINE_SPINLOCK(rtc_lock);
	21	EXPORT_SYMBOL(rtc_lock);
	22
	23	/* last time the RTC got updated */
	24	static long last_rtc_update;
	25
	26	/* time for RTC to update itself in ioclks */
	27	static unsigned long mn10300_rtc_update_period;
	28
f7a56575	29	void read_persistent_clock(struct timespec *ts)
b920de1b DH	30	{
	31	struct rtc_time tm;
	32
	33	get_rtc_time(&tm);
	34
f7a56575	35	ts->tv_sec = mktime(tm.tm_year, tm.tm_mon, tm.tm_mday,
b920de1b	36	tm.tm_hour, tm.tm_min, tm.tm_sec);
f7a56575	37	ts->tv_nsec = 0;
b920de1b DH	38	}
	39
	40	/*
	41	* In order to set the CMOS clock precisely, set_rtc_mmss has to be called 500
	42	* ms after the second nowtime has started, because when nowtime is written
	43	* into the registers of the CMOS clock, it will jump to the next second
	44	* precisely 500 ms later. Check the Motorola MC146818A or Dallas DS12887 data
	45	* sheet for details.
	46	*
	47	* BUG: This routine does not handle hour overflow properly; it just
	48	* sets the minutes. Usually you'll only notice that after reboot!
	49	*/
	50	static int set_rtc_mmss(unsigned long nowtime)
	51	{
	52	unsigned char save_control, save_freq_select;
	53	int retval = 0;
	54	int real_seconds, real_minutes, cmos_minutes;
	55
	56	/* gets recalled with irq locally disabled */
	57	spin_lock(&rtc_lock);
	58	save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being
	59	* set */
	60	CMOS_WRITE(save_control \| RTC_SET, RTC_CONTROL);
	61
	62	save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset
	63	* prescaler */
	64	CMOS_WRITE(save_freq_select \| RTC_DIV_RESET2, RTC_FREQ_SELECT);
	65
	66	cmos_minutes = CMOS_READ(RTC_MINUTES);
	67	if (!(save_control & RTC_DM_BINARY) \|\| RTC_ALWAYS_BCD)
f6a2298c	68	cmos_minutes = bcd2bin(cmos_minutes);
b920de1b DH	69
	70	/*
	71	* since we're only adjusting minutes and seconds,
	72	* don't interfere with hour overflow. This avoids
	73	* messing with unknown time zones but requires your
	74	* RTC not to be off by more than 15 minutes
	75	*/
	76	real_seconds = nowtime % 60;
	77	real_minutes = nowtime / 60;
	78	if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
	79	/* correct for half hour time zone */
	80	real_minutes += 30;
	81	real_minutes %= 60;
	82
	83	if (abs(real_minutes - cmos_minutes) < 30) {
	84	if (!(save_control & RTC_DM_BINARY) \|\| RTC_ALWAYS_BCD) {
f6a2298c AB	85	real_seconds = bin2bcd(real_seconds);
f6a2298c AB	86	real_minutes = bin2bcd(real_minutes);
b920de1b DH	87	}
	88	CMOS_WRITE(real_seconds, RTC_SECONDS);
	89	CMOS_WRITE(real_minutes, RTC_MINUTES);
	90	} else {
	91	printk(KERN_WARNING
	92	"set_rtc_mmss: can't update from %d to %d\n",
	93	cmos_minutes, real_minutes);
	94	retval = -1;
	95	}
	96
	97	/* The following flags have to be released exactly in this order,
	98	* otherwise the DS12887 (popular MC146818A clone with integrated
	99	* battery and quartz) will not reset the oscillator and will not
	100	* update precisely 500 ms later. You won't find this mentioned in
	101	* the Dallas Semiconductor data sheets, but who believes data
	102	* sheets anyway ... -- Markus Kuhn
	103	*/
	104	CMOS_WRITE(save_control, RTC_CONTROL);
	105	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
	106	spin_unlock(&rtc_lock);
	107
	108	return retval;
	109	}
	110
f7a56575	111	int update_persistent_clock(struct timespec now)
b920de1b	112	{
f7a56575	113	return set_rtc_mms(now.tv_sec);
b920de1b DH	114	}
	115
	116	/*
	117	* calibrate the TSC clock against the RTC
	118	*/
	119	void __init calibrate_clock(void)
	120	{
	121	unsigned long count0, counth, count1;
	122	unsigned char status;
	123
	124	/* make sure the RTC is running and is set to operate in 24hr mode */
	125	status = RTSRC;
	126	RTCRB \|= RTCRB_SET;
	127	RTCRB \|= RTCRB_TM_24HR;
	128	RTCRA \|= RTCRA_DVR;
	129	RTCRA &= ~RTCRA_DVR;
	130	RTCRB &= ~RTCRB_SET;
	131
	132	/* work out the clock speed by counting clock cycles between ends of
	133	* the RTC update cycle - track the RTC through one complete update
	134	* cycle (1 second)
	135	*/
	136	startup_timestamp_counter();
	137
	138	while (!(RTCRA & RTCRA_UIP)) {}
	139	while ((RTCRA & RTCRA_UIP)) {}
	140
	141	count0 = TMTSCBC;
	142
	143	while (!(RTCRA & RTCRA_UIP)) {}
	144
	145	counth = TMTSCBC;
	146
	147	while ((RTCRA & RTCRA_UIP)) {}
	148
	149	count1 = TMTSCBC;
	150
	151	shutdown_timestamp_counter();
	152
	153	MN10300_TSCCLK = count0 - count1; /* the timers count down */
	154	mn10300_rtc_update_period = counth - count1;
	155	MN10300_TSC_PER_HZ = MN10300_TSCCLK / HZ;
	156	}