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/intel-mid.h> 16 #include <asm/setup.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(const struct timespec *now) 42 { 43 unsigned long nowtime = now->tv_sec; 44 struct rtc_time tm; 45 int retval = 0; 46 47 rtc_time_to_tm(nowtime, &tm); 48 if (!rtc_valid_tm(&tm)) { 49 retval = mc146818_set_time(&tm); 50 if (retval) 51 printk(KERN_ERR "%s: RTC write failed with error %d\n", 52 __func__, retval); 53 } else { 54 printk(KERN_ERR 55 "%s: Invalid RTC value: write of %lx to RTC failed\n", 56 __func__, nowtime); 57 retval = -EINVAL; 58 } 59 return retval; 60 } 61 62 void mach_get_cmos_time(struct timespec *now) 63 { 64 unsigned int status, year, mon, day, hour, min, sec, century = 0; 65 unsigned long flags; 66 67 /* 68 * If pm_trace abused the RTC as storage, set the timespec to 0, 69 * which tells the caller that this RTC value is unusable. 70 */ 71 if (!pm_trace_rtc_valid()) { 72 now->tv_sec = now->tv_nsec = 0; 73 return; 74 } 75 76 spin_lock_irqsave(&rtc_lock, flags); 77 78 /* 79 * If UIP is clear, then we have >= 244 microseconds before 80 * RTC registers will be updated. Spec sheet says that this 81 * is the reliable way to read RTC - registers. If UIP is set 82 * then the register access might be invalid. 83 */ 84 while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)) 85 cpu_relax(); 86 87 sec = CMOS_READ(RTC_SECONDS); 88 min = CMOS_READ(RTC_MINUTES); 89 hour = CMOS_READ(RTC_HOURS); 90 day = CMOS_READ(RTC_DAY_OF_MONTH); 91 mon = CMOS_READ(RTC_MONTH); 92 year = CMOS_READ(RTC_YEAR); 93 94 #ifdef CONFIG_ACPI 95 if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID && 96 acpi_gbl_FADT.century) 97 century = CMOS_READ(acpi_gbl_FADT.century); 98 #endif 99 100 status = CMOS_READ(RTC_CONTROL); 101 WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY)); 102 103 spin_unlock_irqrestore(&rtc_lock, flags); 104 105 if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) { 106 sec = bcd2bin(sec); 107 min = bcd2bin(min); 108 hour = bcd2bin(hour); 109 day = bcd2bin(day); 110 mon = bcd2bin(mon); 111 year = bcd2bin(year); 112 } 113 114 if (century) { 115 century = bcd2bin(century); 116 year += century * 100; 117 } else 118 year += CMOS_YEARS_OFFS; 119 120 now->tv_sec = mktime(year, mon, day, hour, min, sec); 121 now->tv_nsec = 0; 122 } 123 124 /* Routines for accessing the CMOS RAM/RTC. */ 125 unsigned char rtc_cmos_read(unsigned char addr) 126 { 127 unsigned char val; 128 129 lock_cmos_prefix(addr); 130 outb(addr, RTC_PORT(0)); 131 val = inb(RTC_PORT(1)); 132 lock_cmos_suffix(addr); 133 134 return val; 135 } 136 EXPORT_SYMBOL(rtc_cmos_read); 137 138 void rtc_cmos_write(unsigned char val, unsigned char addr) 139 { 140 lock_cmos_prefix(addr); 141 outb(addr, RTC_PORT(0)); 142 outb(val, RTC_PORT(1)); 143 lock_cmos_suffix(addr); 144 } 145 EXPORT_SYMBOL(rtc_cmos_write); 146 147 int update_persistent_clock(struct timespec now) 148 { 149 return x86_platform.set_wallclock(&now); 150 } 151 152 /* not static: needed by APM */ 153 void read_persistent_clock(struct timespec *ts) 154 { 155 x86_platform.get_wallclock(ts); 156 } 157 158 159 static struct resource rtc_resources[] = { 160 [0] = { 161 .start = RTC_PORT(0), 162 .end = RTC_PORT(1), 163 .flags = IORESOURCE_IO, 164 }, 165 [1] = { 166 .start = RTC_IRQ, 167 .end = RTC_IRQ, 168 .flags = IORESOURCE_IRQ, 169 } 170 }; 171 172 static struct platform_device rtc_device = { 173 .name = "rtc_cmos", 174 .id = -1, 175 .resource = rtc_resources, 176 .num_resources = ARRAY_SIZE(rtc_resources), 177 }; 178 179 static __init int add_rtc_cmos(void) 180 { 181 #ifdef CONFIG_PNP 182 static const char * const ids[] __initconst = 183 { "PNP0b00", "PNP0b01", "PNP0b02", }; 184 struct pnp_dev *dev; 185 struct pnp_id *id; 186 int i; 187 188 pnp_for_each_dev(dev) { 189 for (id = dev->id; id; id = id->next) { 190 for (i = 0; i < ARRAY_SIZE(ids); i++) { 191 if (compare_pnp_id(id, ids[i]) != 0) 192 return 0; 193 } 194 } 195 } 196 #endif 197 if (!x86_platform.legacy.rtc) 198 return -ENODEV; 199 200 platform_device_register(&rtc_device); 201 dev_info(&rtc_device.dev, 202 "registered platform RTC device (no PNP device found)\n"); 203 204 return 0; 205 } 206 device_initcall(add_rtc_cmos); 207