2 * Support for periodic interrupts (100 per second) and for getting
3 * the current time from the RTC on Power Macintoshes.
5 * We use the decrementer register for our periodic interrupts.
7 * Paul Mackerras August 1996.
8 * Copyright (C) 1996 Paul Mackerras.
10 #include <linux/config.h>
11 #include <linux/errno.h>
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/param.h>
15 #include <linux/string.h>
17 #include <linux/init.h>
18 #include <linux/time.h>
19 #include <linux/adb.h>
20 #include <linux/pmu.h>
21 #include <linux/interrupt.h>
23 #include <asm/sections.h>
25 #include <asm/system.h>
27 #include <asm/pgtable.h>
28 #include <asm/machdep.h>
30 #include <asm/nvram.h>
35 #define DBG(x...) printk(x)
40 extern void setup_default_decr(void);
42 extern unsigned long ppc_tb_freq;
43 extern unsigned long ppc_proc_freq;
45 /* Apparently the RTC stores seconds since 1 Jan 1904 */
46 #define RTC_OFFSET 2082844800
49 * Calibrate the decrementer frequency with the VIA timer 1.
51 #define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */
53 extern struct timezone sys_tz;
54 extern void to_tm(int tim, struct rtc_time * tm);
56 void __pmac pmac_get_rtc_time(struct rtc_time *tm)
58 struct adb_request req;
61 /* Get the time from the RTC */
62 if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
66 if (req.reply_len != 4)
67 printk(KERN_ERR "pmac_get_rtc_time: got %d byte reply\n",
69 now = (req.reply[0] << 24) + (req.reply[1] << 16)
70 + (req.reply[2] << 8) + req.reply[3];
71 DBG("get: %u -> %u\n", (int)now, (int)(now - RTC_OFFSET));
78 DBG("-> tm_mday: %d, tm_mon: %d, tm_year: %d, %d:%02d:%02d\n",
79 tm->tm_mday, tm->tm_mon, tm->tm_year,
80 tm->tm_hour, tm->tm_min, tm->tm_sec);
83 int __pmac pmac_set_rtc_time(struct rtc_time *tm)
85 struct adb_request req;
88 DBG("set: tm_mday: %d, tm_mon: %d, tm_year: %d, %d:%02d:%02d\n",
89 tm->tm_mday, tm->tm_mon, tm->tm_year,
90 tm->tm_hour, tm->tm_min, tm->tm_sec);
92 nowtime = mktime(tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
93 tm->tm_hour, tm->tm_min, tm->tm_sec);
94 DBG("-> %u -> %u\n", (int)nowtime, (int)(nowtime + RTC_OFFSET));
95 nowtime += RTC_OFFSET;
97 if (pmu_request(&req, NULL, 5, PMU_SET_RTC,
98 nowtime >> 24, nowtime >> 16, nowtime >> 8, nowtime) < 0)
100 while (!req.complete)
102 if (req.reply_len != 0)
103 printk(KERN_ERR "pmac_set_rtc_time: got %d byte reply\n",
108 void __init pmac_get_boot_time(struct rtc_time *tm)
110 pmac_get_rtc_time(tm);
112 #ifdef disabled__CONFIG_NVRAM
116 delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16;
117 delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8;
118 delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb);
119 if (delta & 0x00800000UL)
120 delta |= 0xFF000000UL;
121 dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0);
122 printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60,
128 * Query the OF and get the decr frequency.
129 * This was taken from the pmac time_init() when merging the prep/pmac
132 void __init pmac_calibrate_decr(void)
134 struct device_node *cpu;
135 unsigned int freq, *fp;
136 struct div_result divres;
139 * The cpu node should have a timebase-frequency property
140 * to tell us the rate at which the decrementer counts.
142 cpu = find_type_devices("cpu");
144 panic("can't find cpu node in time_init");
145 fp = (unsigned int *) get_property(cpu, "timebase-frequency", NULL);
147 panic("can't get cpu timebase frequency");
149 printk("time_init: decrementer frequency = %u.%.6u MHz\n",
150 freq/1000000, freq%1000000);
151 tb_ticks_per_jiffy = freq / HZ;
152 tb_ticks_per_sec = tb_ticks_per_jiffy * HZ;
153 tb_ticks_per_usec = freq / 1000000;
154 tb_to_us = mulhwu_scale_factor(freq, 1000000);
155 div128_by_32( 1024*1024, 0, tb_ticks_per_sec, &divres );
156 tb_to_xs = divres.result_low;
159 fp = (unsigned int *)get_property(cpu, "clock-frequency", NULL);
161 panic("can't get cpu processor frequency");
164 setup_default_decr();