/* * linux/arch/i386/kernel/time.c * * Copyright (C) 1991, 1992, 1995 Linus Torvalds * * Adapted for PowerPC (PreP) by Gary Thomas * Modified by Cort Dougan (cort@cs.nmt.edu) * copied and modified from intel version * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "time.h" /* * The motorola uses the m48t18 rtc (includes DS1643) whose registers * are at a higher end of nvram (1ff8-1fff) than the ibm mc146818 * rtc (ds1386) which has regs at addr 0-d). The intel gets * past this because the bios emulates the mc146818. * * Why in the world did they have to use different clocks? * * Right now things are hacked to check which machine we're on then * use the appropriate macro. This is very very ugly and I should * probably have a function that checks which machine we're on then * does things correctly transparently or a function pointer which * is setup at boot time to use the correct addresses. * -- Cort */ /* * Set the hardware clock. -- Cort */ __prep int mc146818_set_rtc_time(unsigned long nowtime) { unsigned char save_control, save_freq_select; struct rtc_time tm; to_tm(nowtime, &tm); /* 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); tm.tm_year = (tm.tm_year - 1900) % 100; if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BIN_TO_BCD(tm.tm_sec); BIN_TO_BCD(tm.tm_min); BIN_TO_BCD(tm.tm_hour); BIN_TO_BCD(tm.tm_mon); BIN_TO_BCD(tm.tm_mday); BIN_TO_BCD(tm.tm_year); } CMOS_WRITE(tm.tm_sec, RTC_SECONDS); CMOS_WRITE(tm.tm_min, RTC_MINUTES); CMOS_WRITE(tm.tm_hour, RTC_HOURS); CMOS_WRITE(tm.tm_mon, RTC_MONTH); CMOS_WRITE(tm.tm_mday, RTC_DAY_OF_MONTH); CMOS_WRITE(tm.tm_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 */ CMOS_WRITE(save_control, RTC_CONTROL); CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); return 0; } __prep unsigned long mc146818_get_rtc_time(void) { unsigned int year, mon, day, hour, min, sec; int 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. */ /* read RTC exactly on falling edge of update flag */ for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */ if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) break; for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */ if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)) break; do { /* Isn't this overkill ? UIP above should guarantee consistency */ 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); } while (sec != CMOS_READ(RTC_SECONDS)); if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { BCD_TO_BIN(sec); BCD_TO_BIN(min); BCD_TO_BIN(hour); BCD_TO_BIN(day); BCD_TO_BIN(mon); BCD_TO_BIN(year); } if ((year += 1900) < 1970) year += 100; return mktime(year, mon, day, hour, min, sec); } __prep int mk48t59_set_rtc_time(unsigned long nowtime) { unsigned char save_control; struct rtc_time tm; to_tm(nowtime, &tm); /* tell the clock it's being written */ save_control = ppc_md.nvram_read_val(MK48T59_RTC_CONTROLA); ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, (save_control | MK48T59_RTC_CA_WRITE)); tm.tm_year = (tm.tm_year - 1900) % 100; BIN_TO_BCD(tm.tm_sec); BIN_TO_BCD(tm.tm_min); BIN_TO_BCD(tm.tm_hour); BIN_TO_BCD(tm.tm_mon); BIN_TO_BCD(tm.tm_mday); BIN_TO_BCD(tm.tm_year); ppc_md.nvram_write_val(MK48T59_RTC_SECONDS, tm.tm_sec); ppc_md.nvram_write_val(MK48T59_RTC_MINUTES, tm.tm_min); ppc_md.nvram_write_val(MK48T59_RTC_HOURS, tm.tm_hour); ppc_md.nvram_write_val(MK48T59_RTC_MONTH, tm.tm_mon); ppc_md.nvram_write_val(MK48T59_RTC_DAY_OF_MONTH, tm.tm_mday); ppc_md.nvram_write_val(MK48T59_RTC_YEAR, tm.tm_year); /* Turn off the write bit. */ ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control); return 0; } __prep unsigned long mk48t59_get_rtc_time(void) { unsigned char save_control; unsigned int year, mon, day, hour, min, sec; int i; /* Make sure the time is not stopped. */ save_control = ppc_md.nvram_read_val(MK48T59_RTC_CONTROLB); ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, (save_control & (~MK48T59_RTC_CB_STOP))); /* Now make sure the read bit is off so the value will change. */ save_control = ppc_md.nvram_read_val(MK48T59_RTC_CONTROLA); save_control &= ~MK48T59_RTC_CA_READ; ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control); /* Read the seconds value to see when it changes. */ sec = ppc_md.nvram_read_val(MK48T59_RTC_SECONDS); /* Wait until the seconds value changes, then read the value. */ for (i = 0 ; i < 1000000 ; i++) { /* may take up to 1 second... */ if (ppc_md.nvram_read_val(MK48T59_RTC_SECONDS) != sec) { break; } } /* Set the register to read the value. */ ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, (save_control | MK48T59_RTC_CA_READ)); sec = ppc_md.nvram_read_val(MK48T59_RTC_SECONDS); min = ppc_md.nvram_read_val(MK48T59_RTC_MINUTES); hour = ppc_md.nvram_read_val(MK48T59_RTC_HOURS); day = ppc_md.nvram_read_val(MK48T59_RTC_DAY_OF_MONTH); mon = ppc_md.nvram_read_val(MK48T59_RTC_MONTH); year = ppc_md.nvram_read_val(MK48T59_RTC_YEAR); /* Let the time values change again. */ ppc_md.nvram_write_val(MK48T59_RTC_CONTROLA, save_control); BCD_TO_BIN(sec); BCD_TO_BIN(min); BCD_TO_BIN(hour); BCD_TO_BIN(day); BCD_TO_BIN(mon); BCD_TO_BIN(year); year = year + 1900; if (year < 1970) { year += 100; } return mktime(year, mon, day, hour, min, sec); }