1 files changed, 226 insertions, 0 deletions

diff --git a/arch/ppc64/kernel/maple_time.c b/arch/ppc64/kernel/maple_time.c
new file mode 100644
index 000000000000..07ce7895b43d
--- /dev/null
+++ b/arch/ppc64/kernel/maple_time.c
@@ -0,0 +1,226 @@
+/*
+ *  arch/ppc64/kernel/maple_time.c
+ *
+ *  (c) Copyright 2004 Benjamin Herrenschmidt (benh@kernel.crashing.org),
+ *                     IBM Corp. 
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ *
+ */
+
+#undef DEBUG
+
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/kernel.h>
+#include <linux/param.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/adb.h>
+#include <linux/pmu.h>
+#include <linux/interrupt.h>
+#include <linux/mc146818rtc.h>
+#include <linux/bcd.h>
+
+#include <asm/sections.h>
+#include <asm/prom.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/pgtable.h>
+#include <asm/machdep.h>
+#include <asm/time.h>
+
+#ifdef DEBUG
+#define DBG(x...) printk(x)
+#else
+#define DBG(x...)
+#endif
+
+extern void setup_default_decr(void);
+extern void GregorianDay(struct rtc_time * tm);
+
+extern unsigned long ppc_tb_freq;
+extern unsigned long ppc_proc_freq;
+static int maple_rtc_addr;
+
+static int maple_clock_read(int addr)
+{
+        outb_p(addr, maple_rtc_addr);
+        return inb_p(maple_rtc_addr+1);
+}
+
+static void maple_clock_write(unsigned long val, int addr)
+{
+        outb_p(addr, maple_rtc_addr);
+        outb_p(val, maple_rtc_addr+1);
+}
+
+void maple_get_rtc_time(struct rtc_time *tm)
+{
+        int uip, i;
+
+        /* The Linux interpretation of the CMOS clock register contents:
+         * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
+         * RTC registers show the second which has precisely just started.
+         * Let's hope other operating systems interpret the RTC the same way.
+         */
+
+        /* Since the UIP flag is set for about 2.2 ms and the clock
+         * is typically written with a precision of 1 jiffy, trying
+         * to obtain a precision better than a few milliseconds is
+         * an illusion. Only consistency is interesting, this also
+         * allows to use the routine for /dev/rtc without a potential
+         * 1 second kernel busy loop triggered by any reader of /dev/rtc.
+         */
+
+        for (i = 0; i<1000000; i++) {
+                uip = maple_clock_read(RTC_FREQ_SELECT);
+                tm->tm_sec = maple_clock_read(RTC_SECONDS);
+                tm->tm_min = maple_clock_read(RTC_MINUTES);
+                tm->tm_hour = maple_clock_read(RTC_HOURS);
+                tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH);
+                tm->tm_mon = maple_clock_read(RTC_MONTH);
+                tm->tm_year = maple_clock_read(RTC_YEAR);
+                uip |= maple_clock_read(RTC_FREQ_SELECT);
+                if ((uip & RTC_UIP)==0)
+                        break;
+        }
+
+        if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY)
+            || RTC_ALWAYS_BCD) {
+                BCD_TO_BIN(tm->tm_sec);
+                BCD_TO_BIN(tm->tm_min);
+                BCD_TO_BIN(tm->tm_hour);
+                BCD_TO_BIN(tm->tm_mday);
+                BCD_TO_BIN(tm->tm_mon);
+                BCD_TO_BIN(tm->tm_year);
+          }
+        if ((tm->tm_year + 1900) < 1970)
+                tm->tm_year += 100;
+
+        GregorianDay(tm);
+}
+
+int maple_set_rtc_time(struct rtc_time *tm)
+{
+        unsigned char save_control, save_freq_select;
+        int sec, min, hour, mon, mday, year;
+
+        spin_lock(&rtc_lock);
+
+        save_control = maple_clock_read(RTC_CONTROL); /* tell the clock it's being set */
+
+        maple_clock_write((save_control|RTC_SET), RTC_CONTROL);
+
+        save_freq_select = maple_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
+
+        maple_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
+
+        sec = tm->tm_sec;
+        min = tm->tm_min;
+        hour = tm->tm_hour;
+        mon = tm->tm_mon;
+        mday = tm->tm_mday;
+        year = tm->tm_year;
+
+        if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+                BIN_TO_BCD(sec);
+                BIN_TO_BCD(min);
+                BIN_TO_BCD(hour);
+                BIN_TO_BCD(mon);
+                BIN_TO_BCD(mday);
+                BIN_TO_BCD(year);
+        }
+        maple_clock_write(sec, RTC_SECONDS);
+        maple_clock_write(min, RTC_MINUTES);
+        maple_clock_write(hour, RTC_HOURS);
+        maple_clock_write(mon, RTC_MONTH);
+        maple_clock_write(mday, RTC_DAY_OF_MONTH);
+        maple_clock_write(year, RTC_YEAR);
+
+        /* 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
+         */
+        maple_clock_write(save_control, RTC_CONTROL);
+        maple_clock_write(save_freq_select, RTC_FREQ_SELECT);
+
+        spin_unlock(&rtc_lock);
+
+        return 0;
+}
+
+void __init maple_get_boot_time(struct rtc_time *tm)
+{
+        struct device_node *rtcs;
+
+        rtcs = find_compatible_devices("rtc", "pnpPNP,b00");
+        if (rtcs && rtcs->addrs) {
+                maple_rtc_addr = rtcs->addrs[0].address;
+                printk(KERN_INFO "Maple: Found RTC at 0x%x\n", maple_rtc_addr);
+        } else {
+                maple_rtc_addr = RTC_PORT(0); /* legacy address */
+                printk(KERN_INFO "Maple: No device node for RTC, assuming "
+                       "legacy address (0x%x)\n", maple_rtc_addr);
+        }
+        
+        maple_get_rtc_time(tm);
+}
+
+/* XXX FIXME: Some sane defaults: 125 MHz timebase, 1GHz processor */
+#define DEFAULT_TB_FREQ         125000000UL
+#define DEFAULT_PROC_FREQ       (DEFAULT_TB_FREQ * 8)
+
+void __init maple_calibrate_decr(void)
+{
+        struct device_node *cpu;
+        struct div_result divres;
+        unsigned int *fp = NULL;
+
+        /*
+         * The cpu node should have a timebase-frequency property
+         * to tell us the rate at which the decrementer counts.
+         */
+        cpu = of_find_node_by_type(NULL, "cpu");
+
+        ppc_tb_freq = DEFAULT_TB_FREQ;
+        if (cpu != 0)
+                fp = (unsigned int *)get_property(cpu, "timebase-frequency", NULL);
+        if (fp != NULL)
+                ppc_tb_freq = *fp;
+        else
+                printk(KERN_ERR "WARNING: Estimating decrementer frequency (not found)\n");
+        fp = NULL;
+        ppc_proc_freq = DEFAULT_PROC_FREQ;
+        if (cpu != 0)
+                fp = (unsigned int *)get_property(cpu, "clock-frequency", NULL);
+        if (fp != NULL)
+                ppc_proc_freq = *fp;
+        else
+                printk(KERN_ERR "WARNING: Estimating processor frequency (not found)\n");
+
+        of_node_put(cpu);
+
+        printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n",
+               ppc_tb_freq/1000000, ppc_tb_freq%1000000);
+        printk(KERN_INFO "time_init: processor frequency   = %lu.%.6lu MHz\n",
+               ppc_proc_freq/1000000, ppc_proc_freq%1000000);
+
+        tb_ticks_per_jiffy = ppc_tb_freq / HZ;
+        tb_ticks_per_sec = tb_ticks_per_jiffy * HZ;
+        tb_ticks_per_usec = ppc_tb_freq / 1000000;
+        tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
+        div128_by_32(1024*1024, 0, tb_ticks_per_sec, &divres);
+        tb_to_xs = divres.result_low;
+
+        setup_default_decr();
+}