/arch/powerpc/platforms/chrp/time.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
  4 *
  5 * Adapted for PowerPC (PReP) by Gary Thomas
  6 * Modified by Cort Dougan (cort@cs.nmt.edu).
  7 * Copied and modified from arch/i386/kernel/time.c
  8 *
  9 */
 10#include <linux/errno.h>
 11#include <linux/sched.h>
 12#include <linux/kernel.h>
 13#include <linux/param.h>
 14#include <linux/string.h>
 15#include <linux/mm.h>
 16#include <linux/interrupt.h>
 17#include <linux/time.h>
 18#include <linux/timex.h>
 19#include <linux/kernel_stat.h>
 20#include <linux/mc146818rtc.h>
 21#include <linux/init.h>
 22#include <linux/bcd.h>
 23#include <linux/ioport.h>
 24
 25#include <asm/io.h>
 26#include <asm/nvram.h>
 27#include <asm/prom.h>
 28#include <asm/sections.h>
 29#include <asm/time.h>
 30
 31#include <platforms/chrp/chrp.h>
 32
 33extern spinlock_t rtc_lock;
 34
 35#define NVRAM_AS0  0x74
 36#define NVRAM_AS1  0x75
 37#define NVRAM_DATA 0x77
 38
 39static int nvram_as1 = NVRAM_AS1;
 40static int nvram_as0 = NVRAM_AS0;
 41static int nvram_data = NVRAM_DATA;
 42
 43long __init chrp_time_init(void)
 44{
 45	struct device_node *rtcs;
 46	struct resource r;
 47	int base;
 48
 49	rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
 50	if (rtcs == NULL)
 51		rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
 52	if (rtcs == NULL)
 53		return 0;
 54	if (of_address_to_resource(rtcs, 0, &r)) {
 55		of_node_put(rtcs);
 56		return 0;
 57	}
 58	of_node_put(rtcs);
 59
 60	base = r.start;
 61	nvram_as1 = 0;
 62	nvram_as0 = base;
 63	nvram_data = base + 1;
 64
 65	return 0;
 66}
 67
 68static int chrp_cmos_clock_read(int addr)
 69{
 70	if (nvram_as1 != 0)
 71		outb(addr>>8, nvram_as1);
 72	outb(addr, nvram_as0);
 73	return (inb(nvram_data));
 74}
 75
 76static void chrp_cmos_clock_write(unsigned long val, int addr)
 77{
 78	if (nvram_as1 != 0)
 79		outb(addr>>8, nvram_as1);
 80	outb(addr, nvram_as0);
 81	outb(val, nvram_data);
 82	return;
 83}
 84
 85/*
 86 * Set the hardware clock. -- Cort
 87 */
 88int chrp_set_rtc_time(struct rtc_time *tmarg)
 89{
 90	unsigned char save_control, save_freq_select;
 91	struct rtc_time tm = *tmarg;
 92
 93	spin_lock(&rtc_lock);
 94
 95	save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
 96
 97	chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
 98
 99	save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
100
101	chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
102
103	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
104		tm.tm_sec = bin2bcd(tm.tm_sec);
105		tm.tm_min = bin2bcd(tm.tm_min);
106		tm.tm_hour = bin2bcd(tm.tm_hour);
107		tm.tm_mon = bin2bcd(tm.tm_mon);
108		tm.tm_mday = bin2bcd(tm.tm_mday);
109		tm.tm_year = bin2bcd(tm.tm_year);
110	}
111	chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
112	chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
113	chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
114	chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
115	chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
116	chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
117
118	/* The following flags have to be released exactly in this order,
119	 * otherwise the DS12887 (popular MC146818A clone with integrated
120	 * battery and quartz) will not reset the oscillator and will not
121	 * update precisely 500 ms later. You won't find this mentioned in
122	 * the Dallas Semiconductor data sheets, but who believes data
123	 * sheets anyway ...                           -- Markus Kuhn
124	 */
125	chrp_cmos_clock_write(save_control, RTC_CONTROL);
126	chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
127
128	spin_unlock(&rtc_lock);
129	return 0;
130}
131
132void chrp_get_rtc_time(struct rtc_time *tm)
133{
134	unsigned int year, mon, day, hour, min, sec;
135
136	do {
137		sec = chrp_cmos_clock_read(RTC_SECONDS);
138		min = chrp_cmos_clock_read(RTC_MINUTES);
139		hour = chrp_cmos_clock_read(RTC_HOURS);
140		day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
141		mon = chrp_cmos_clock_read(RTC_MONTH);
142		year = chrp_cmos_clock_read(RTC_YEAR);
143	} while (sec != chrp_cmos_clock_read(RTC_SECONDS));
144
145	if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
146		sec = bcd2bin(sec);
147		min = bcd2bin(min);
148		hour = bcd2bin(hour);
149		day = bcd2bin(day);
150		mon = bcd2bin(mon);
151		year = bcd2bin(year);
152	}
153	if (year < 70)
154		year += 100;
155	tm->tm_sec = sec;
156	tm->tm_min = min;
157	tm->tm_hour = hour;
158	tm->tm_mday = day;
159	tm->tm_mon = mon;
160	tm->tm_year = year;
161}