/* * 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/intel-mid.h>#include <asm/setup.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. */int mach_set_rtc_mmss(const struct timespec *now){	unsigned long nowtime = now->tv_sec;	struct rtc_time tm;	int retval = 0; 	rtc_time_to_tm(nowtime, &tm);	if (!rtc_valid_tm(&tm)) {		retval = mc146818_set_time(&tm);		if (retval)			printk(KERN_ERR "%s: RTC write failed with error %d\n",			       __func__, retval);	} else {		printk(KERN_ERR		       "%s: Invalid RTC value: write of %lx to RTC failed\n",			__func__, nowtime);		retval = -EINVAL;	}	return retval;} void mach_get_cmos_time(struct timespec *now){	unsigned int status, year, mon, day, hour, min, sec, century = 0;	unsigned long flags; 	/*	 * If pm_trace abused the RTC as storage, set the timespec to 0,	 * which tells the caller that this RTC value is unusable.	 */	if (!pm_trace_rtc_valid()) {		now->tv_sec = now->tv_nsec = 0;		return;	} 	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;	} else		year += CMOS_YEARS_OFFS; 	now->tv_sec = mktime(year, mon, day, hour, min, sec);	now->tv_nsec = 0;} /* 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);} /* not static: needed by APM */void read_persistent_clock(struct timespec *ts){	x86_platform.get_wallclock(ts);}  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 * const 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 (!x86_platform.legacy.rtc)		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);