1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
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
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>
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>
26 #include <asm/nvram.h>
28 #include <asm/sections.h>
31 #include <platforms/chrp/chrp.h>
33 extern spinlock_t rtc_lock;
35 #define NVRAM_AS0 0x74
36 #define NVRAM_AS1 0x75
37 #define NVRAM_DATA 0x77
39 static int nvram_as1 = NVRAM_AS1;
40 static int nvram_as0 = NVRAM_AS0;
41 static int nvram_data = NVRAM_DATA;
43 long __init chrp_time_init(void)
45 struct device_node *rtcs;
49 rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
51 rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
54 if (of_address_to_resource(rtcs, 0, &r)) {
63 nvram_data = base + 1;
68 static int chrp_cmos_clock_read(int addr)
71 outb(addr>>8, nvram_as1);
72 outb(addr, nvram_as0);
73 return (inb(nvram_data));
76 static void chrp_cmos_clock_write(unsigned long val, int addr)
79 outb(addr>>8, nvram_as1);
80 outb(addr, nvram_as0);
81 outb(val, nvram_data);
86 * Set the hardware clock. -- Cort
88 int chrp_set_rtc_time(struct rtc_time *tmarg)
90 unsigned char save_control, save_freq_select;
91 struct rtc_time tm = *tmarg;
95 save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
97 chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
99 save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
101 chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
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);
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);
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
125 chrp_cmos_clock_write(save_control, RTC_CONTROL);
126 chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
128 spin_unlock(&rtc_lock);
132 void chrp_get_rtc_time(struct rtc_time *tm)
134 unsigned int year, mon, day, hour, min, sec;
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));
145 if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
148 hour = bcd2bin(hour);
151 year = bcd2bin(year);