/* * RTC related functions */ #include <linux/platform_device.h> #include <linux/mc146818rtc.h> #include <linux/acpi.h> #include <linux/bcd.h> #include <linux/pnp.h> #include <asm/vsyscall.h> #include <asm/x86_init.h> #include <asm/time.h> #ifdef CONFIG_X86_32 /* * This is a special lock that is owned by the CPU and holds the index * register we are working with. It is required for NMI access to the * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details. */ volatile unsigned long cmos_lock; EXPORT_SYMBOL(cmos_lock); #endif /* CONFIG_X86_32 */ /* For two digit years assume time is always after that */ #define CMOS_YEARS_OFFS 2000 DEFINE_SPINLOCK(rtc_lock); EXPORT_SYMBOL(rtc_lock); /* * In order to set the CMOS clock precisely, set_rtc_mmss has to be * called 500 ms after the second nowtime has started, because when * nowtime is written into the registers of the CMOS clock, it will * jump to the next second precisely 500 ms later. Check the Motorola * MC146818A or Dallas DS12887 data sheet for details. * * BUG: This routine does not handle hour overflow properly; it just * sets the minutes. Usually you'll only notice that after reboot! */ int mach_set_rtc_mmss(unsigned long nowtime) { int real_seconds, real_minutes, cmos_minutes; unsigned char save_control, save_freq_select; int retval = 0; /* tell the clock it's being set */ save_control = CMOS_READ(RTC_CONTROL); CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); /* stop and reset prescaler */ save_freq_select = CMOS_READ(RTC_FREQ_SELECT); CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); cmos_minutes = CMOS_READ(RTC_MINUTES); if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) cmos_minutes = bcd2bin(cmos_minutes); /* * since we're only adjusting minutes and seconds, * don't interfere with hour overflow. This avoids * messing with unknown time zones but requires your * RTC not to be off by more than 15 minutes */ real_seconds = nowtime % 60; real_minutes = nowtime / 60; /* correct for half hour time zone */ if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) real_minutes += 30; real_minutes %= 60; if (abs(real_minutes - cmos_minutes) < 30) { if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { real_seconds = bin2bcd(real_seconds); real_minutes = bin2bcd(real_minutes); } CMOS_WRITE(real_seconds, RTC_SECONDS); CMOS_WRITE(real_minutes, RTC_MINUTES); } else { printk(KERN_WARNING "set_rtc_mmss: can't update from %d to %d\n", cmos_minutes, real_minutes); retval = -1; } /* The following flags have to be released exactly in this order, * otherwise the DS12887 (popular MC146818A clone with integrated * battery and quartz) will not reset the oscillator and will not * update precisely 500 ms later. You won't find this mentioned in * the Dallas Semiconductor data sheets, but who believes data * sheets anyway ... -- Markus Kuhn */ CMOS_WRITE(save_control, RTC_CONTROL); CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); return retval; } unsigned long mach_get_cmos_time(void) { unsigned int status, year, mon, day, hour, min, sec, century = 0; /* * If UIP is clear, then we have >= 244 microseconds before * RTC registers will be updated. Spec sheet says that this * is the reliable way to read RTC - registers. If UIP is set * then the register access might be invalid. */ while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)) cpu_relax(); sec = CMOS_READ(RTC_SECONDS); min = CMOS_READ(RTC_MINUTES); hour = CMOS_READ(RTC_HOURS); day = CMOS_READ(RTC_DAY_OF_MONTH); mon = CMOS_READ(RTC_MONTH); year = CMOS_READ(RTC_YEAR); #ifdef CONFIG_ACPI if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID && acpi_gbl_FADT.century) century = CMOS_READ(acpi_gbl_FADT.century); #endif status = CMOS_READ(RTC_CONTROL); WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY)); if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) { sec = bcd2bin(sec); min = bcd2bin(min); hour = bcd2bin(hour); day = bcd2bin(day); mon = bcd2bin(mon); year = bcd2bin(year); } if (century) { century = bcd2bin(century); year += century * 100; printk(KERN_INFO "Extended CMOS year: %d\n", century * 100); } else year += CMOS_YEARS_OFFS; return mktime(year, mon, day, hour, min, sec); } /* Routines for accessing the CMOS RAM/RTC. */ unsigned char rtc_cmos_read(unsigned char addr) { unsigned char val; lock_cmos_prefix(addr); outb(addr, RTC_PORT(0)); val = inb(RTC_PORT(1)); lock_cmos_suffix(addr); return val; } EXPORT_SYMBOL(rtc_cmos_read); void rtc_cmos_write(unsigned char val, unsigned char addr) { lock_cmos_prefix(addr); outb(addr, RTC_PORT(0)); outb(val, RTC_PORT(1)); lock_cmos_suffix(addr); } EXPORT_SYMBOL(rtc_cmos_write); int update_persistent_clock(struct timespec now) { unsigned long flags; int retval; spin_lock_irqsave(&rtc_lock, flags); retval = x86_platform.set_wallclock(now.tv_sec); spin_unlock_irqrestore(&rtc_lock, flags); return retval; } /* not static: needed by APM */ void read_persistent_clock(struct timespec *ts) { unsigned long retval, flags; spin_lock_irqsave(&rtc_lock, flags); retval = x86_platform.get_wallclock(); spin_unlock_irqrestore(&rtc_lock, flags); ts->tv_sec = retval; ts->tv_nsec = 0; } unsigned long long native_read_tsc(void) { return __native_read_tsc(); } EXPORT_SYMBOL(native_read_tsc); static struct resource rtc_resources[] = { [0] = { .start = RTC_PORT(0), .end = RTC_PORT(1), .flags = IORESOURCE_IO, }, [1] = { .start = RTC_IRQ, .end = RTC_IRQ, .flags = IORESOURCE_IRQ, } }; static struct platform_device rtc_device = { .name = "rtc_cmos", .id = -1, .resource = rtc_resources, .num_resources = ARRAY_SIZE(rtc_resources), }; static __init int add_rtc_cmos(void) { #ifdef CONFIG_PNP static const char *ids[] __initconst = { "PNP0b00", "PNP0b01", "PNP0b02", }; struct pnp_dev *dev; struct pnp_id *id; int i; pnp_for_each_dev(dev) { for (id = dev->id; id; id = id->next) { for (i = 0; i < ARRAY_SIZE(ids); i++) { if (compare_pnp_id(id, ids[i]) != 0) return 0; } } } #endif platform_device_register(&rtc_device); dev_info(&rtc_device.dev, "registered platform RTC device (no PNP device found)\n"); return 0; } device_initcall(add_rtc_cmos);