1 files changed, 256 insertions, 0 deletions
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c
new file mode 100644
index 00000000..af6db6ec
--- /dev/null
+++ b/arch/x86/kernel/rtc.c
@@ -0,0 +1,256 @@
+/*
+ * 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);