1 files changed, 323 insertions, 0 deletions

diff --git a/arch/alpha/kernel/rtc.c b/arch/alpha/kernel/rtc.c
new file mode 100644
index 000000000000..c8d284d8521f
--- /dev/null
+++ b/arch/alpha/kernel/rtc.c
@@ -0,0 +1,323 @@
+/*
+ *  linux/arch/alpha/kernel/rtc.c
+ *
+ *  Copyright (C) 1991, 1992, 1995, 1999, 2000  Linus Torvalds
+ *
+ * This file contains date handling.
+ */
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/string.h>
+#include <linux/mc146818rtc.h>
+#include <linux/bcd.h>
+#include <linux/rtc.h>
+#include <linux/platform_device.h>
+
+#include <asm/rtc.h>
+
+#include "proto.h"
+
+
+/*
+ * Support for the RTC device.
+ *
+ * We don't want to use the rtc-cmos driver, because we don't want to support
+ * alarms, as that would be indistinguishable from timer interrupts.
+ *
+ * Further, generic code is really, really tied to a 1900 epoch.  This is
+ * true in __get_rtc_time as well as the users of struct rtc_time e.g.
+ * rtc_tm_to_time.  Thankfully all of the other epochs in use are later
+ * than 1900, and so it's easy to adjust.
+ */
+
+static unsigned long rtc_epoch;
+
+static int __init
+specifiy_epoch(char *str)
+{
+        unsigned long epoch = simple_strtoul(str, NULL, 0);
+        if (epoch < 1900)
+                printk("Ignoring invalid user specified epoch %lu\n", epoch);
+        else
+                rtc_epoch = epoch;
+        return 1;
+}
+__setup("epoch=", specifiy_epoch);
+
+static void __init
+init_rtc_epoch(void)
+{
+        int epoch, year, ctrl;
+
+        if (rtc_epoch != 0) {
+                /* The epoch was specified on the command-line.  */
+                return;
+        }
+
+        /* Detect the epoch in use on this computer.  */
+        ctrl = CMOS_READ(RTC_CONTROL);
+        year = CMOS_READ(RTC_YEAR);
+        if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+                year = bcd2bin(year);
+
+        /* PC-like is standard; used for year >= 70 */
+        epoch = 1900;
+        if (year < 20) {
+                epoch = 2000;
+        } else if (year >= 20 && year < 48) {
+                /* NT epoch */
+                epoch = 1980;
+        } else if (year >= 48 && year < 70) {
+                /* Digital UNIX epoch */
+                epoch = 1952;
+        }
+        rtc_epoch = epoch;
+
+        printk(KERN_INFO "Using epoch %d for rtc year %d\n", epoch, year);
+}
+
+static int
+alpha_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+        __get_rtc_time(tm);
+
+        /* Adjust for non-default epochs.  It's easier to depend on the
+           generic __get_rtc_time and adjust the epoch here than create
+           a copy of __get_rtc_time with the edits we need.  */
+        if (rtc_epoch != 1900) {
+                int year = tm->tm_year;
+                /* Undo the century adjustment made in __get_rtc_time.  */
+                if (year >= 100)
+                        year -= 100;
+                year += rtc_epoch - 1900;
+                /* Redo the century adjustment with the epoch in place.  */
+                if (year <= 69)
+                        year += 100;
+                tm->tm_year = year;
+        }
+
+        return rtc_valid_tm(tm);
+}
+
+static int
+alpha_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+        struct rtc_time xtm;
+
+        if (rtc_epoch != 1900) {
+                xtm = *tm;
+                xtm.tm_year -= rtc_epoch - 1900;
+                tm = &xtm;
+        }
+
+        return __set_rtc_time(tm);
+}
+
+static int
+alpha_rtc_set_mmss(struct device *dev, unsigned long nowtime)
+{
+        int retval = 0;
+        int real_seconds, real_minutes, cmos_minutes;
+        unsigned char save_control, save_freq_select;
+
+        /* Note: This code only updates minutes and seconds.  Comments
+           indicate this was to avoid messing with unknown time zones,
+           and with the epoch nonsense described above.  In order for
+           this to work, the existing clock cannot be off by more than
+           15 minutes.
+
+           ??? This choice is may be out of date.  The x86 port does
+           not have problems with timezones, and the epoch processing has
+           now been fixed in alpha_set_rtc_time.
+
+           In either case, one can always force a full rtc update with
+           the userland hwclock program, so surely 15 minute accuracy
+           is no real burden.  */
+
+        /* In order to set the CMOS clock precisely, we have 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.  */
+
+        /* irq are locally disabled here */
+        spin_lock(&rtc_lock);
+        /* 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);
+
+        real_seconds = nowtime % 60;
+        real_minutes = nowtime / 60;
+        if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1) {
+                /* correct for half hour time zone */
+                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(&rtc_lock);
+
+        return retval;
+}
+
+static int
+alpha_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
+{
+        switch (cmd) {
+        case RTC_EPOCH_READ:
+                return put_user(rtc_epoch, (unsigned long __user *)arg);
+        case RTC_EPOCH_SET:
+                if (arg < 1900)
+                        return -EINVAL;
+                rtc_epoch = arg;
+                return 0;
+        default:
+                return -ENOIOCTLCMD;
+        }
+}
+
+static const struct rtc_class_ops alpha_rtc_ops = {
+        .read_time = alpha_rtc_read_time,
+        .set_time = alpha_rtc_set_time,
+        .set_mmss = alpha_rtc_set_mmss,
+        .ioctl = alpha_rtc_ioctl,
+};
+
+/*
+ * Similarly, except do the actual CMOS access on the boot cpu only.
+ * This requires marshalling the data across an interprocessor call.
+ */
+
+#if defined(CONFIG_SMP) && \
+    (defined(CONFIG_ALPHA_GENERIC) || defined(CONFIG_ALPHA_MARVEL))
+# define HAVE_REMOTE_RTC 1
+
+union remote_data {
+        struct rtc_time *tm;
+        unsigned long now;
+        long retval;
+};
+
+static void
+do_remote_read(void *data)
+{
+        union remote_data *x = data;
+        x->retval = alpha_rtc_read_time(NULL, x->tm);
+}
+
+static int
+remote_read_time(struct device *dev, struct rtc_time *tm)
+{
+        union remote_data x;
+        if (smp_processor_id() != boot_cpuid) {
+                x.tm = tm;
+                smp_call_function_single(boot_cpuid, do_remote_read, &x, 1);
+                return x.retval;
+        }
+        return alpha_rtc_read_time(NULL, tm);
+}
+
+static void
+do_remote_set(void *data)
+{
+        union remote_data *x = data;
+        x->retval = alpha_rtc_set_time(NULL, x->tm);
+}
+
+static int
+remote_set_time(struct device *dev, struct rtc_time *tm)
+{
+        union remote_data x;
+        if (smp_processor_id() != boot_cpuid) {
+                x.tm = tm;
+                smp_call_function_single(boot_cpuid, do_remote_set, &x, 1);
+                return x.retval;
+        }
+        return alpha_rtc_set_time(NULL, tm);
+}
+
+static void
+do_remote_mmss(void *data)
+{
+        union remote_data *x = data;
+        x->retval = alpha_rtc_set_mmss(NULL, x->now);
+}
+
+static int
+remote_set_mmss(struct device *dev, unsigned long now)
+{
+        union remote_data x;
+        if (smp_processor_id() != boot_cpuid) {
+                x.now = now;
+                smp_call_function_single(boot_cpuid, do_remote_mmss, &x, 1);
+                return x.retval;
+        }
+        return alpha_rtc_set_mmss(NULL, now);
+}
+
+static const struct rtc_class_ops remote_rtc_ops = {
+        .read_time = remote_read_time,
+        .set_time = remote_set_time,
+        .set_mmss = remote_set_mmss,
+        .ioctl = alpha_rtc_ioctl,
+};
+#endif
+
+static int __init
+alpha_rtc_init(void)
+{
+        const struct rtc_class_ops *ops;
+        struct platform_device *pdev;
+        struct rtc_device *rtc;
+        const char *name;
+
+        init_rtc_epoch();
+        name = "rtc-alpha";
+        ops = &alpha_rtc_ops;
+
+#ifdef HAVE_REMOTE_RTC
+        if (alpha_mv.rtc_boot_cpu_only)
+                ops = &remote_rtc_ops;
+#endif
+
+        pdev = platform_device_register_simple(name, -1, NULL, 0);
+        rtc = devm_rtc_device_register(&pdev->dev, name, ops, THIS_MODULE);
+        if (IS_ERR(rtc))
+                return PTR_ERR(rtc);
+
+        platform_set_drvdata(pdev, rtc);
+        return 0;
+}
+device_initcall(alpha_rtc_init);