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 33 extern spinlock_t rtc_lock; 34 35 #define NVRAM_AS0 0x74 36 #define NVRAM_AS1 0x75 37 #define NVRAM_DATA 0x77 38 39 static int nvram_as1 = NVRAM_AS1; 40 static int nvram_as0 = NVRAM_AS0; 41 static int nvram_data = NVRAM_DATA; 42 43 long __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 68 static 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 76 static 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 */ 88 int 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 } 131 132 void 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 } 162