1 /* 2 * RTC related functions 3 */ 4 #include <linux/platform_device.h> 5 #include <linux/mc146818rtc.h> 6 #include <linux/acpi.h> 7 #include <linux/bcd.h> 8 #include <linux/export.h> 9 #include <linux/pnp.h> 10 #include <linux/of.h> 11 12 #include <asm/vsyscall.h> 13 #include <asm/x86_init.h> 14 #include <asm/time.h> 15 #include <asm/mrst.h> 16 #include <asm/rtc.h> 17 18 #ifdef CONFIG_X86_32 19 /* 20 * This is a special lock that is owned by the CPU and holds the index 21 * register we are working with. It is required for NMI access to the 22 * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details. 23 */ 24 volatile unsigned long cmos_lock; 25 EXPORT_SYMBOL(cmos_lock); 26 #endif /* CONFIG_X86_32 */ 27 28 /* For two digit years assume time is always after that */ 29 #define CMOS_YEARS_OFFS 2000 30 31 DEFINE_SPINLOCK(rtc_lock); 32 EXPORT_SYMBOL(rtc_lock); 33 34 /* 35 * In order to set the CMOS clock precisely, set_rtc_mmss has to be 36 * called 500 ms after the second nowtime has started, because when 37 * nowtime is written into the registers of the CMOS clock, it will 38 * jump to the next second precisely 500 ms later. Check the Motorola 39 * MC146818A or Dallas DS12887 data sheet for details. 40 */ 41 int mach_set_rtc_mmss(unsigned long nowtime) 42 { 43 struct rtc_time tm; 44 int retval = 0; 45 46 rtc_time_to_tm(nowtime, &tm); 47 if (!rtc_valid_tm(&tm)) { 48 retval = set_rtc_time(&tm); 49 if (retval) 50 printk(KERN_ERR "%s: RTC write failed with error %d\n", 51 __FUNCTION__, retval); 52 } else { 53 printk(KERN_ERR 54 "%s: Invalid RTC value: write of %lx to RTC failed\n", 55 __FUNCTION__, nowtime); 56 retval = -EINVAL; 57 } 58 return retval; 59 } 60 61 unsigned long mach_get_cmos_time(void) 62 { 63 unsigned int status, year, mon, day, hour, min, sec, century = 0; 64 unsigned long flags; 65 66 spin_lock_irqsave(&rtc_lock, flags); 67 68 /* 69 * If UIP is clear, then we have >= 244 microseconds before 70 * RTC registers will be updated. Spec sheet says that this 71 * is the reliable way to read RTC - registers. If UIP is set 72 * then the register access might be invalid. 73 */ 74 while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)) 75 cpu_relax(); 76 77 sec = CMOS_READ(RTC_SECONDS); 78 min = CMOS_READ(RTC_MINUTES); 79 hour = CMOS_READ(RTC_HOURS); 80 day = CMOS_READ(RTC_DAY_OF_MONTH); 81 mon = CMOS_READ(RTC_MONTH); 82 year = CMOS_READ(RTC_YEAR); 83 84 #ifdef CONFIG_ACPI 85 if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID && 86 acpi_gbl_FADT.century) 87 century = CMOS_READ(acpi_gbl_FADT.century); 88 #endif 89 90 status = CMOS_READ(RTC_CONTROL); 91 WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY)); 92 93 spin_unlock_irqrestore(&rtc_lock, flags); 94 95 if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) { 96 sec = bcd2bin(sec); 97 min = bcd2bin(min); 98 hour = bcd2bin(hour); 99 day = bcd2bin(day); 100 mon = bcd2bin(mon); 101 year = bcd2bin(year); 102 } 103 104 if (century) { 105 century = bcd2bin(century); 106 year += century * 100; 107 } else 108 year += CMOS_YEARS_OFFS; 109 110 return mktime(year, mon, day, hour, min, sec); 111 } 112 113 /* Routines for accessing the CMOS RAM/RTC. */ 114 unsigned char rtc_cmos_read(unsigned char addr) 115 { 116 unsigned char val; 117 118 lock_cmos_prefix(addr); 119 outb(addr, RTC_PORT(0)); 120 val = inb(RTC_PORT(1)); 121 lock_cmos_suffix(addr); 122 123 return val; 124 } 125 EXPORT_SYMBOL(rtc_cmos_read); 126 127 void rtc_cmos_write(unsigned char val, unsigned char addr) 128 { 129 lock_cmos_prefix(addr); 130 outb(addr, RTC_PORT(0)); 131 outb(val, RTC_PORT(1)); 132 lock_cmos_suffix(addr); 133 } 134 EXPORT_SYMBOL(rtc_cmos_write); 135 136 int update_persistent_clock(struct timespec now) 137 { 138 return x86_platform.set_wallclock(now.tv_sec); 139 } 140 141 /* not static: needed by APM */ 142 void read_persistent_clock(struct timespec *ts) 143 { 144 unsigned long retval; 145 146 retval = x86_platform.get_wallclock(); 147 148 ts->tv_sec = retval; 149 ts->tv_nsec = 0; 150 } 151 152 153 static struct resource rtc_resources[] = { 154 [0] = { 155 .start = RTC_PORT(0), 156 .end = RTC_PORT(1), 157 .flags = IORESOURCE_IO, 158 }, 159 [1] = { 160 .start = RTC_IRQ, 161 .end = RTC_IRQ, 162 .flags = IORESOURCE_IRQ, 163 } 164 }; 165 166 static struct platform_device rtc_device = { 167 .name = "rtc_cmos", 168 .id = -1, 169 .resource = rtc_resources, 170 .num_resources = ARRAY_SIZE(rtc_resources), 171 }; 172 173 static __init int add_rtc_cmos(void) 174 { 175 #ifdef CONFIG_PNP 176 static const char * const const ids[] __initconst = 177 { "PNP0b00", "PNP0b01", "PNP0b02", }; 178 struct pnp_dev *dev; 179 struct pnp_id *id; 180 int i; 181 182 pnp_for_each_dev(dev) { 183 for (id = dev->id; id; id = id->next) { 184 for (i = 0; i < ARRAY_SIZE(ids); i++) { 185 if (compare_pnp_id(id, ids[i]) != 0) 186 return 0; 187 } 188 } 189 } 190 #endif 191 if (of_have_populated_dt()) 192 return 0; 193 194 /* Intel MID platforms don't have ioport rtc */ 195 if (mrst_identify_cpu()) 196 return -ENODEV; 197 198 platform_device_register(&rtc_device); 199 dev_info(&rtc_device.dev, 200 "registered platform RTC device (no PNP device found)\n"); 201 202 return 0; 203 } 204 device_initcall(add_rtc_cmos); 205