/* * RTC related functions */#include <linux/platform_device.h>#include <linux/mc146818rtc.h>#include <linux/acpi.h>#include <linux/bcd.h>#include <linux/export.h>#include <linux/pnp.h>#include <linux/of.h> #include <asm/vsyscall.h>#include <asm/x86_init.h>#include <asm/time.h>#include <asm/mrst.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;	unsigned long flags;	int retval = 0; 	spin_lock_irqsave(&rtc_lock, flags); 	 /* 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_once(KERN_NOTICE		       "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); 	spin_unlock_irqrestore(&rtc_lock, flags); 	return retval;} unsigned long mach_get_cmos_time(void){	unsigned int status, year, mon, day, hour, min, sec, century = 0;	unsigned long flags; 	spin_lock_irqsave(&rtc_lock, flags); 	/*	 * 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)); 	spin_unlock_irqrestore(&rtc_lock, flags); 	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){	return x86_platform.set_wallclock(now.tv_sec);} /* not static: needed by APM */void read_persistent_clock(struct timespec *ts){	unsigned long retval; 	retval = x86_platform.get_wallclock(); 	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	if (of_have_populated_dt())		return 0; 	/* Intel MID platforms don't have ioport rtc */	if (mrst_identify_cpu())		return -ENODEV; 	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);