/* * time.c for smdk24a0 * by Hyok S. Choi * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Based on linux/include/asm-arm/arch-s3c2410/time.h */ #include #include #include #include #include #include #include #include #include #include #include #include /* copy from linux/arch/arm/kernel/time.c */ #ifndef BCD_TO_BIN #define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10) #endif #ifndef BIN_TO_BCD #define BIN_TO_BCD(val) ((val)=(((val)/10)<<4) + (val)%10) #endif #ifndef RTC_LEAP_YEAR #define RTC_LEAP_YEAR 2000 #endif extern spinlock_t rtc_lock; unsigned long elfin_get_rtc_time(void) { unsigned int year, mon, day, hour, min, sec; spin_lock_irq(&rtc_lock); read_rtc_bcd_time: year = BCDYEAR & Msk_RTCYEAR; mon = BCDMON & Msk_RTCMON; day = BCDDAY & Msk_RTCDAY; hour = BCDHOUR & Msk_RTCHOUR; min = BCDMIN & Msk_RTCMIN; sec = BCDSEC & Msk_RTCSEC; if (sec == 0) { /* If BCDSEC is zero, reread all bcd registers. See Section 17.2 READ/WRITE REGISTERS for more info. */ goto read_rtc_bcd_time; } spin_unlock_irq(&rtc_lock); BCD_TO_BIN(year); BCD_TO_BIN(mon); BCD_TO_BIN(day); BCD_TO_BIN(hour); BCD_TO_BIN(min); BCD_TO_BIN(sec); year += RTC_LEAP_YEAR; return (mktime(year, mon, day, hour, min, sec)); } /* * Copyed from drivers/char/sa1100-rtc.c. */ #define epoch 1970 static const unsigned char days_in_mo[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; #ifndef is_leap #define is_leap(year) \ ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0)) #endif /* * Converts seconds since 1970-01-01 00:00:00 to Gregorian date. */ static void decodetime (unsigned long t, struct rtc_time *tval) { unsigned long days, month, year, rem; days = t / 86400; rem = t % 86400; tval->tm_hour = rem / 3600; rem %= 3600; tval->tm_min = rem / 60; tval->tm_sec = rem % 60; tval->tm_wday = (4 + days) % 7; #define LEAPS_THRU_END_OF(y) ((y)/4 - (y)/100 + (y)/400) year = epoch; while (days >= (365 + is_leap(year))) { unsigned long yg = year + days / 365; days -= ((yg - year) * 365 + LEAPS_THRU_END_OF (yg - 1) - LEAPS_THRU_END_OF (year - 1)); year = yg; } tval->tm_year = year - 1900; tval->tm_yday = days + 1; month = 0; if (days >= 31) { days -= 31; month++; if (days >= (28 + is_leap(year))) { days -= (28 + is_leap(year)); month++; while (days >= days_in_mo[month]) { days -= days_in_mo[month]; month++; } } } tval->tm_mon = month; tval->tm_mday = days + 1; } int elfin_set_rtc(void) { unsigned long current_time = xtime.tv_sec; unsigned char year, mon, day, hour, min, sec; signed int yeardiff; struct rtc_time rtc_tm; decodetime(current_time, &rtc_tm); yeardiff = (rtc_tm.tm_year + 1900) - RTC_LEAP_YEAR; if (yeardiff < 0) { /* S3C2410 RTC forces that the year must be higher or equal than 2000, so initailize it. */ yeardiff = 0; } year = (unsigned char) yeardiff; mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */ day = rtc_tm.tm_mday; hour = rtc_tm.tm_hour; min = rtc_tm.tm_min; sec = rtc_tm.tm_sec; BIN_TO_BCD(sec); BIN_TO_BCD(min); BIN_TO_BCD(hour); BIN_TO_BCD(day); BIN_TO_BCD(mon); BIN_TO_BCD(year); spin_lock_irq(&rtc_lock); RTCCON |= RTCCON_EN; BCDSEC = sec & Msk_RTCSEC; BCDMIN = min & Msk_RTCMIN; BCDHOUR = hour & Msk_RTCHOUR; BCDDAY = day & Msk_RTCDAY; BCDMON = mon & Msk_RTCMON; BCDYEAR = year & Msk_RTCYEAR; RTCCON &= ~RTCCON_EN; spin_unlock_irq(&rtc_lock); return 0; } static unsigned long elfin_gettimeoffset(void) { unsigned long elapsed, usec; unsigned long latch; /* Use TCNTB4 as LATCH */ latch = TCNTB4; elapsed = latch - TCNTO4; usec = (elapsed * (tick_nsec / 1000)) / latch; // hcyun return usec; } static irqreturn_t elfin_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) { // do_set_rtc(); timer_tick(regs); return IRQ_HANDLED; } static struct irqaction elfin_timer_irq = { .name = "S3C24A0 Timer Tick", .flags = SA_INTERRUPT | SA_TIMER, .handler = elfin_timer_interrupt }; #define TCON4_PRESCALER_VALUE 15 #define TCON4_DIVIDER_VALUE 2 #define TCON4_PERIOD 10 /* miliseconds */ void __init elfin_time_init(void) { set_rtc = elfin_set_rtc; xtime.tv_sec = elfin_get_rtc_time(); /* set timer interrupt */ TCFG0 = (TCFG0_DZONE(0) | TCFG0_PRE1(TCON4_PRESCALER_VALUE) | TCFG0_PRE0(TCON4_PRESCALER_VALUE)); /* * period = (prescaler value + 1) * (divider value) * buffer count / PCLK * buffer count = period * PCLK / divider value / (prescaler value + 1) * * e.g.) * * PCLK = 50700000 Hz, divider value = 2, prescaler value = 15 * period = 10ms * * buffer count = ((10 / 1000) * 50700000) / 2 / (15+1) * = 15843.75 */ printk("DEBUG: PCLK=%d, Prescaler=%d, Divider=%d\n", elfin_get_bus_clk(GET_PCLK), TCON4_PRESCALER_VALUE+1, TCON4_DIVIDER_VALUE ); TCNTB4 = ((TCON4_PERIOD * ((elfin_get_bus_clk(GET_PCLK))/1000)) / TCON4_DIVIDER_VALUE) / (TCON4_PRESCALER_VALUE + 1); printk("DEBUG: timer count %d\n", TCNTB4); TCON = (TCON_4_AUTO | TCON_4_UPDATE | (0 << 20)); elfin_timer_irq.handler = elfin_timer_interrupt; printk("Timer Initialized.. IRQ=%d\n", IRQ_TIMER4); setup_irq(IRQ_TIMER4, &elfin_timer_irq); TCON = (TCON_4_AUTO | (0 << 21) | TCON_4_ONOFF); } struct sys_timer elfin_timer = { .init = elfin_time_init, .offset = elfin_gettimeoffset, }; EXPORT_SYMBOL(elfin_get_rtc_time); EXPORT_SYMBOL(elfin_set_rtc);