[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);

/* 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_mmss(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
b920de1b DH	23	/* time for RTC to update itself in ioclks */
	24	static unsigned long mn10300_rtc_update_period;
	25
f7a56575	26	void read_persistent_clock(struct timespec *ts)
b920de1b DH	27	{
	28	struct rtc_time tm;
	29
	30	get_rtc_time(&tm);
	31
f7a56575	32	ts->tv_sec = mktime(tm.tm_year, tm.tm_mon, tm.tm_mday,
b920de1b	33	tm.tm_hour, tm.tm_min, tm.tm_sec);
f7a56575	34	ts->tv_nsec = 0;
b920de1b DH	35	}
	36
	37	/*
	38	* In order to set the CMOS clock precisely, set_rtc_mmss has to be called 500
	39	* ms after the second nowtime has started, because when nowtime is written
	40	* into the registers of the CMOS clock, it will jump to the next second
	41	* precisely 500 ms later. Check the Motorola MC146818A or Dallas DS12887 data
	42	* sheet for details.
	43	*
	44	* BUG: This routine does not handle hour overflow properly; it just
	45	* sets the minutes. Usually you'll only notice that after reboot!
	46	*/
	47	static int set_rtc_mmss(unsigned long nowtime)
	48	{
	49	unsigned char save_control, save_freq_select;
	50	int retval = 0;
	51	int real_seconds, real_minutes, cmos_minutes;
	52
	53	/* gets recalled with irq locally disabled */
	54	spin_lock(&rtc_lock);
	55	save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being
	56	* set */
	57	CMOS_WRITE(save_control \| RTC_SET, RTC_CONTROL);
	58
	59	save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset
	60	* prescaler */
	61	CMOS_WRITE(save_freq_select \| RTC_DIV_RESET2, RTC_FREQ_SELECT);
	62
	63	cmos_minutes = CMOS_READ(RTC_MINUTES);
	64	if (!(save_control & RTC_DM_BINARY) \|\| RTC_ALWAYS_BCD)
f6a2298c	65	cmos_minutes = bcd2bin(cmos_minutes);
b920de1b DH	66
	67	/*
	68	* since we're only adjusting minutes and seconds,
	69	* don't interfere with hour overflow. This avoids
	70	* messing with unknown time zones but requires your
	71	* RTC not to be off by more than 15 minutes
	72	*/
	73	real_seconds = nowtime % 60;
	74	real_minutes = nowtime / 60;
	75	if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
	76	/* correct for half hour time zone */
	77	real_minutes += 30;
	78	real_minutes %= 60;
	79
	80	if (abs(real_minutes - cmos_minutes) < 30) {
	81	if (!(save_control & RTC_DM_BINARY) \|\| RTC_ALWAYS_BCD) {
f6a2298c AB	82	real_seconds = bin2bcd(real_seconds);
f6a2298c AB	83	real_minutes = bin2bcd(real_minutes);
b920de1b DH	84	}
	85	CMOS_WRITE(real_seconds, RTC_SECONDS);
	86	CMOS_WRITE(real_minutes, RTC_MINUTES);
	87	} else {
	88	printk(KERN_WARNING
	89	"set_rtc_mmss: can't update from %d to %d\n",
	90	cmos_minutes, real_minutes);
	91	retval = -1;
	92	}
	93
	94	/* The following flags have to be released exactly in this order,
	95	* otherwise the DS12887 (popular MC146818A clone with integrated
	96	* battery and quartz) will not reset the oscillator and will not
	97	* update precisely 500 ms later. You won't find this mentioned in
	98	* the Dallas Semiconductor data sheets, but who believes data
	99	* sheets anyway ... -- Markus Kuhn
	100	*/
	101	CMOS_WRITE(save_control, RTC_CONTROL);
	102	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
	103	spin_unlock(&rtc_lock);
	104
	105	return retval;
	106	}
	107
f7a56575	108	int update_persistent_clock(struct timespec now)
b920de1b	109	{
35579576	110	return set_rtc_mmss(now.tv_sec);
b920de1b DH	111	}
	112
	113	/*
	114	* calibrate the TSC clock against the RTC
	115	*/
	116	void __init calibrate_clock(void)
	117	{
	118	unsigned long count0, counth, count1;
	119	unsigned char status;
	120
	121	/* make sure the RTC is running and is set to operate in 24hr mode */
	122	status = RTSRC;
	123	RTCRB \|= RTCRB_SET;
	124	RTCRB \|= RTCRB_TM_24HR;
	125	RTCRA \|= RTCRA_DVR;
	126	RTCRA &= ~RTCRA_DVR;
	127	RTCRB &= ~RTCRB_SET;
	128
	129	/* work out the clock speed by counting clock cycles between ends of
	130	* the RTC update cycle - track the RTC through one complete update
	131	* cycle (1 second)
	132	*/
	133	startup_timestamp_counter();
	134
	135	while (!(RTCRA & RTCRA_UIP)) {}
	136	while ((RTCRA & RTCRA_UIP)) {}
	137
	138	count0 = TMTSCBC;
	139
	140	while (!(RTCRA & RTCRA_UIP)) {}
	141
	142	counth = TMTSCBC;
	143
	144	while ((RTCRA & RTCRA_UIP)) {}
	145
	146	count1 = TMTSCBC;
	147
	148	shutdown_timestamp_counter();
	149
	150	MN10300_TSCCLK = count0 - count1; /* the timers count down */
	151	mn10300_rtc_update_period = counth - count1;
	152	MN10300_TSC_PER_HZ = MN10300_TSCCLK / HZ;
	153	}