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