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/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(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 = set_rtc_time(&tm); 50 if (retval) 51 printk(KERN_ERR "%s: RTC write failed with error %d\n", 52 __FUNCTION__, retval); 53 } else { 54 printk(KERN_ERR 55 "%s: Invalid RTC value: write of %lx to RTC failed\n", 56 __FUNCTION__, 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 spin_lock_irqsave(&rtc_lock, flags); 68 69 /* 70 * If UIP is clear, then we have >= 244 microseconds before 71 * RTC registers will be updated. Spec sheet says that this 72 * is the reliable way to read RTC - registers. If UIP is set 73 * then the register access might be invalid. 74 */ 75 while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)) 76 cpu_relax(); 77 78 sec = CMOS_READ(RTC_SECONDS); 79 min = CMOS_READ(RTC_MINUTES); 80 hour = CMOS_READ(RTC_HOURS); 81 day = CMOS_READ(RTC_DAY_OF_MONTH); 82 mon = CMOS_READ(RTC_MONTH); 83 year = CMOS_READ(RTC_YEAR); 84 85 #ifdef CONFIG_ACPI 86 if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID && 87 acpi_gbl_FADT.century) 88 century = CMOS_READ(acpi_gbl_FADT.century); 89 #endif 90 91 status = CMOS_READ(RTC_CONTROL); 92 WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY)); 93 94 spin_unlock_irqrestore(&rtc_lock, flags); 95 96 if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) { 97 sec = bcd2bin(sec); 98 min = bcd2bin(min); 99 hour = bcd2bin(hour); 100 day = bcd2bin(day); 101 mon = bcd2bin(mon); 102 year = bcd2bin(year); 103 } 104 105 if (century) { 106 century = bcd2bin(century); 107 year += century * 100; 108 } else 109 year += CMOS_YEARS_OFFS; 110 111 now->tv_sec = mktime(year, mon, day, hour, min, sec); 112 now->tv_nsec = 0; 113 } 114 115 /* Routines for accessing the CMOS RAM/RTC. */ 116 unsigned char rtc_cmos_read(unsigned char addr) 117 { 118 unsigned char val; 119 120 lock_cmos_prefix(addr); 121 outb(addr, RTC_PORT(0)); 122 val = inb(RTC_PORT(1)); 123 lock_cmos_suffix(addr); 124 125 return val; 126 } 127 EXPORT_SYMBOL(rtc_cmos_read); 128 129 void rtc_cmos_write(unsigned char val, unsigned char addr) 130 { 131 lock_cmos_prefix(addr); 132 outb(addr, RTC_PORT(0)); 133 outb(val, RTC_PORT(1)); 134 lock_cmos_suffix(addr); 135 } 136 EXPORT_SYMBOL(rtc_cmos_write); 137 138 int update_persistent_clock(struct timespec now) 139 { 140 return x86_platform.set_wallclock(&now); 141 } 142 143 /* not static: needed by APM */ 144 void read_persistent_clock(struct timespec *ts) 145 { 146 x86_platform.get_wallclock(ts); 147 } 148 149 150 static struct resource rtc_resources[] = { 151 [0] = { 152 .start = RTC_PORT(0), 153 .end = RTC_PORT(1), 154 .flags = IORESOURCE_IO, 155 }, 156 [1] = { 157 .start = RTC_IRQ, 158 .end = RTC_IRQ, 159 .flags = IORESOURCE_IRQ, 160 } 161 }; 162 163 static struct platform_device rtc_device = { 164 .name = "rtc_cmos", 165 .id = -1, 166 .resource = rtc_resources, 167 .num_resources = ARRAY_SIZE(rtc_resources), 168 }; 169 170 static __init int add_rtc_cmos(void) 171 { 172 #ifdef CONFIG_PNP 173 static const char * const const ids[] __initconst = 174 { "PNP0b00", "PNP0b01", "PNP0b02", }; 175 struct pnp_dev *dev; 176 struct pnp_id *id; 177 int i; 178 179 pnp_for_each_dev(dev) { 180 for (id = dev->id; id; id = id->next) { 181 for (i = 0; i < ARRAY_SIZE(ids); i++) { 182 if (compare_pnp_id(id, ids[i]) != 0) 183 return 0; 184 } 185 } 186 } 187 #endif 188 if (of_have_populated_dt()) 189 return 0; 190 191 /* Intel MID platforms don't have ioport rtc */ 192 if (intel_mid_identify_cpu()) 193 return -ENODEV; 194 195 #ifdef CONFIG_ACPI 196 if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) { 197 /* This warning can likely go away again in a year or two. */ 198 pr_info("ACPI: not registering RTC platform device\n"); 199 return -ENODEV; 200 } 201 #endif 202 203 platform_device_register(&rtc_device); 204 dev_info(&rtc_device.dev, 205 "registered platform RTC device (no PNP device found)\n"); 206 207 return 0; 208 } 209 device_initcall(add_rtc_cmos); 210