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 extern spinlock_t rtc_lock; 32 33 #define NVRAM_AS0 0x74 34 #define NVRAM_AS1 0x75 35 #define NVRAM_DATA 0x77 36 37 static int nvram_as1 = NVRAM_AS1; 38 static int nvram_as0 = NVRAM_AS0; 39 static int nvram_data = NVRAM_DATA; 40 41 long __init chrp_time_init(void) 42 { 43 struct device_node *rtcs; 44 struct resource r; 45 int base; 46 47 rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00"); 48 if (rtcs == NULL) 49 rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc"); 50 if (rtcs == NULL) 51 return 0; 52 if (of_address_to_resource(rtcs, 0, &r)) { 53 of_node_put(rtcs); 54 return 0; 55 } 56 of_node_put(rtcs); 57 58 base = r.start; 59 nvram_as1 = 0; 60 nvram_as0 = base; 61 nvram_data = base + 1; 62 63 return 0; 64 } 65 66 int chrp_cmos_clock_read(int addr) 67 { 68 if (nvram_as1 != 0) 69 outb(addr>>8, nvram_as1); 70 outb(addr, nvram_as0); 71 return (inb(nvram_data)); 72 } 73 74 void chrp_cmos_clock_write(unsigned long val, int addr) 75 { 76 if (nvram_as1 != 0) 77 outb(addr>>8, nvram_as1); 78 outb(addr, nvram_as0); 79 outb(val, nvram_data); 80 return; 81 } 82 83 /* 84 * Set the hardware clock. -- Cort 85 */ 86 int chrp_set_rtc_time(struct rtc_time *tmarg) 87 { 88 unsigned char save_control, save_freq_select; 89 struct rtc_time tm = *tmarg; 90 91 spin_lock(&rtc_lock); 92 93 save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */ 94 95 chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL); 96 97 save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */ 98 99 chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); 100 101 if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 102 tm.tm_sec = bin2bcd(tm.tm_sec); 103 tm.tm_min = bin2bcd(tm.tm_min); 104 tm.tm_hour = bin2bcd(tm.tm_hour); 105 tm.tm_mon = bin2bcd(tm.tm_mon); 106 tm.tm_mday = bin2bcd(tm.tm_mday); 107 tm.tm_year = bin2bcd(tm.tm_year); 108 } 109 chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS); 110 chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES); 111 chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS); 112 chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH); 113 chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH); 114 chrp_cmos_clock_write(tm.tm_year,RTC_YEAR); 115 116 /* The following flags have to be released exactly in this order, 117 * otherwise the DS12887 (popular MC146818A clone with integrated 118 * battery and quartz) will not reset the oscillator and will not 119 * update precisely 500 ms later. You won't find this mentioned in 120 * the Dallas Semiconductor data sheets, but who believes data 121 * sheets anyway ... -- Markus Kuhn 122 */ 123 chrp_cmos_clock_write(save_control, RTC_CONTROL); 124 chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT); 125 126 spin_unlock(&rtc_lock); 127 return 0; 128 } 129 130 void chrp_get_rtc_time(struct rtc_time *tm) 131 { 132 unsigned int year, mon, day, hour, min, sec; 133 134 do { 135 sec = chrp_cmos_clock_read(RTC_SECONDS); 136 min = chrp_cmos_clock_read(RTC_MINUTES); 137 hour = chrp_cmos_clock_read(RTC_HOURS); 138 day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH); 139 mon = chrp_cmos_clock_read(RTC_MONTH); 140 year = chrp_cmos_clock_read(RTC_YEAR); 141 } while (sec != chrp_cmos_clock_read(RTC_SECONDS)); 142 143 if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 144 sec = bcd2bin(sec); 145 min = bcd2bin(min); 146 hour = bcd2bin(hour); 147 day = bcd2bin(day); 148 mon = bcd2bin(mon); 149 year = bcd2bin(year); 150 } 151 if (year < 70) 152 year += 100; 153 tm->tm_sec = sec; 154 tm->tm_min = min; 155 tm->tm_hour = hour; 156 tm->tm_mday = day; 157 tm->tm_mon = mon; 158 tm->tm_year = year; 159 } 160