/arch/ppc64/kernel/maple_time.c
https://bitbucket.org/evzijst/gittest · C · 226 lines · 154 code · 36 blank · 36 comment · 18 complexity · 2fd7acae66bb681796170f75be3ca6e9 MD5 · raw file
- /*
- * 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();
- }