1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * (c) Copyright 2004 Benjamin Herrenschmidt (benh@kernel.crashing.org), 4 * IBM Corp. 5 */ 6 7 #undef DEBUG 8 9 #include <linux/errno.h> 10 #include <linux/sched.h> 11 #include <linux/kernel.h> 12 #include <linux/param.h> 13 #include <linux/string.h> 14 #include <linux/mm.h> 15 #include <linux/init.h> 16 #include <linux/time.h> 17 #include <linux/adb.h> 18 #include <linux/pmu.h> 19 #include <linux/interrupt.h> 20 #include <linux/mc146818rtc.h> 21 #include <linux/bcd.h> 22 23 #include <asm/sections.h> 24 #include <asm/prom.h> 25 #include <asm/io.h> 26 #include <asm/pgtable.h> 27 #include <asm/machdep.h> 28 #include <asm/time.h> 29 30 #include "maple.h" 31 32 #ifdef DEBUG 33 #define DBG(x...) printk(x) 34 #else 35 #define DBG(x...) 36 #endif 37 38 static int maple_rtc_addr; 39 40 static int maple_clock_read(int addr) 41 { 42 outb_p(addr, maple_rtc_addr); 43 return inb_p(maple_rtc_addr+1); 44 } 45 46 static void maple_clock_write(unsigned long val, int addr) 47 { 48 outb_p(addr, maple_rtc_addr); 49 outb_p(val, maple_rtc_addr+1); 50 } 51 52 void maple_get_rtc_time(struct rtc_time *tm) 53 { 54 do { 55 tm->tm_sec = maple_clock_read(RTC_SECONDS); 56 tm->tm_min = maple_clock_read(RTC_MINUTES); 57 tm->tm_hour = maple_clock_read(RTC_HOURS); 58 tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH); 59 tm->tm_mon = maple_clock_read(RTC_MONTH); 60 tm->tm_year = maple_clock_read(RTC_YEAR); 61 } while (tm->tm_sec != maple_clock_read(RTC_SECONDS)); 62 63 if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY) 64 || RTC_ALWAYS_BCD) { 65 tm->tm_sec = bcd2bin(tm->tm_sec); 66 tm->tm_min = bcd2bin(tm->tm_min); 67 tm->tm_hour = bcd2bin(tm->tm_hour); 68 tm->tm_mday = bcd2bin(tm->tm_mday); 69 tm->tm_mon = bcd2bin(tm->tm_mon); 70 tm->tm_year = bcd2bin(tm->tm_year); 71 } 72 if ((tm->tm_year + 1900) < 1970) 73 tm->tm_year += 100; 74 75 tm->tm_wday = -1; 76 } 77 78 int maple_set_rtc_time(struct rtc_time *tm) 79 { 80 unsigned char save_control, save_freq_select; 81 int sec, min, hour, mon, mday, year; 82 83 spin_lock(&rtc_lock); 84 85 save_control = maple_clock_read(RTC_CONTROL); /* tell the clock it's being set */ 86 87 maple_clock_write((save_control|RTC_SET), RTC_CONTROL); 88 89 save_freq_select = maple_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */ 90 91 maple_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); 92 93 sec = tm->tm_sec; 94 min = tm->tm_min; 95 hour = tm->tm_hour; 96 mon = tm->tm_mon; 97 mday = tm->tm_mday; 98 year = tm->tm_year; 99 100 if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { 101 sec = bin2bcd(sec); 102 min = bin2bcd(min); 103 hour = bin2bcd(hour); 104 mon = bin2bcd(mon); 105 mday = bin2bcd(mday); 106 year = bin2bcd(year); 107 } 108 maple_clock_write(sec, RTC_SECONDS); 109 maple_clock_write(min, RTC_MINUTES); 110 maple_clock_write(hour, RTC_HOURS); 111 maple_clock_write(mon, RTC_MONTH); 112 maple_clock_write(mday, RTC_DAY_OF_MONTH); 113 maple_clock_write(year, RTC_YEAR); 114 115 /* The following flags have to be released exactly in this order, 116 * otherwise the DS12887 (popular MC146818A clone with integrated 117 * battery and quartz) will not reset the oscillator and will not 118 * update precisely 500 ms later. You won't find this mentioned in 119 * the Dallas Semiconductor data sheets, but who believes data 120 * sheets anyway ... -- Markus Kuhn 121 */ 122 maple_clock_write(save_control, RTC_CONTROL); 123 maple_clock_write(save_freq_select, RTC_FREQ_SELECT); 124 125 spin_unlock(&rtc_lock); 126 127 return 0; 128 } 129 130 static struct resource rtc_iores = { 131 .name = "rtc", 132 .flags = IORESOURCE_IO | IORESOURCE_BUSY, 133 }; 134 135 time64_t __init maple_get_boot_time(void) 136 { 137 struct rtc_time tm; 138 struct device_node *rtcs; 139 140 rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00"); 141 if (rtcs) { 142 struct resource r; 143 if (of_address_to_resource(rtcs, 0, &r)) { 144 printk(KERN_EMERG "Maple: Unable to translate RTC" 145 " address\n"); 146 goto bail; 147 } 148 if (!(r.flags & IORESOURCE_IO)) { 149 printk(KERN_EMERG "Maple: RTC address isn't PIO!\n"); 150 goto bail; 151 } 152 maple_rtc_addr = r.start; 153 printk(KERN_INFO "Maple: Found RTC at IO 0x%x\n", 154 maple_rtc_addr); 155 } 156 bail: 157 if (maple_rtc_addr == 0) { 158 maple_rtc_addr = RTC_PORT(0); /* legacy address */ 159 printk(KERN_INFO "Maple: No device node for RTC, assuming " 160 "legacy address (0x%x)\n", maple_rtc_addr); 161 } 162 163 rtc_iores.start = maple_rtc_addr; 164 rtc_iores.end = maple_rtc_addr + 7; 165 request_resource(&ioport_resource, &rtc_iores); 166 167 maple_get_rtc_time(&tm); 168 return rtc_tm_to_time64(&tm); 169 } 170 171