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Diffstat (limited to 'arch/mips/ite-boards/generic/time.c')
| -rw-r--r-- | arch/mips/ite-boards/generic/time.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/arch/mips/ite-boards/generic/time.c b/arch/mips/ite-boards/generic/time.c new file mode 100644 index 0000000..30a6c0d --- /dev/null +++ b/arch/mips/ite-boards/generic/time.c @@ -0,0 +1,247 @@ +/* + * Carsten Langgaard, carstenl@mips.com + * Copyright (C) 1999,2000 MIPS Technologies, Inc. All rights reserved. + * + * Copyright (C) 2003 MontaVista Software Inc. + * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net + * + * ######################################################################## + * + * This program is free software; you can distribute it and/or modify it + * under the terms of the GNU General Public License (Version 2) as + * published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston MA 02111-1307, USA. + * + * ######################################################################## + * + * Setting up the clock on the MIPS boards. + */ +#include <linux/init.h> +#include <linux/kernel_stat.h> +#include <linux/sched.h> +#include <linux/time.h> +#include <linux/spinlock.h> + +#include <asm/time.h> +#include <asm/mipsregs.h> +#include <asm/ptrace.h> +#include <asm/it8172/it8172.h> +#include <asm/it8172/it8172_int.h> +#include <asm/debug.h> + +#define IT8172_RTC_ADR_REG (IT8172_PCI_IO_BASE + IT_RTC_BASE) +#define IT8172_RTC_DAT_REG (IT8172_RTC_ADR_REG + 1) +#define IT8172_RTC_CENTURY_REG (IT8172_PCI_IO_BASE + IT_RTC_CENTURY) + +static volatile char *rtc_adr_reg = (char*)KSEG1ADDR(IT8172_RTC_ADR_REG); +static volatile char *rtc_dat_reg = (char*)KSEG1ADDR(IT8172_RTC_DAT_REG); +static volatile char *rtc_century_reg = (char*)KSEG1ADDR(IT8172_RTC_CENTURY_REG); + +unsigned char it8172_rtc_read_data(unsigned long addr) +{ + unsigned char retval; + + *rtc_adr_reg = addr; + retval = *rtc_dat_reg; + return retval; +} + +void it8172_rtc_write_data(unsigned char data, unsigned long addr) +{ + *rtc_adr_reg = addr; + *rtc_dat_reg = data; +} + +#undef CMOS_READ +#undef CMOS_WRITE +#define CMOS_READ(addr) it8172_rtc_read_data(addr) +#define CMOS_WRITE(data, addr) it8172_rtc_write_data(data, addr) + +static unsigned char saved_control; /* remember rtc control reg */ +static inline int rtc_24h(void) { return saved_control & RTC_24H; } +static inline int rtc_dm_binary(void) { return saved_control & RTC_DM_BINARY; } + +static inline unsigned char +bin_to_hw(unsigned char c) +{ + if (rtc_dm_binary()) + return c; + else + return ((c/10) << 4) + (c%10); +} + +static inline unsigned char +hw_to_bin(unsigned char c) +{ + if (rtc_dm_binary()) + return c; + else + return (c>>4)*10 + (c &0xf); +} + +/* 0x80 bit indicates pm in 12-hour format */ +static inline unsigned char +hour_bin_to_hw(unsigned char c) +{ + if (rtc_24h()) + return bin_to_hw(c); + if (c >= 12) + return 0x80 | bin_to_hw((c==12)?12:c-12); /* 12 is 12pm */ + else + return bin_to_hw((c==0)?12:c); /* 0 is 12 AM, not 0 am */ +} + +static inline unsigned char +hour_hw_to_bin(unsigned char c) +{ + unsigned char tmp = hw_to_bin(c&0x3f); + if (rtc_24h()) + return tmp; + if (c & 0x80) + return (tmp==12)?12:tmp+12; /* 12pm is 12, not 24 */ + else + return (tmp==12)?0:tmp; /* 12am is 0 */ +} + +static unsigned long r4k_offset; /* Amount to increment compare reg each time */ +static unsigned long r4k_cur; /* What counter should be at next timer irq */ +extern unsigned int mips_hpt_frequency; + +/* + * Figure out the r4k offset, the amount to increment the compare + * register for each time tick. + * Use the RTC to calculate offset. + */ +static unsigned long __init cal_r4koff(void) +{ + unsigned int flags; + + local_irq_save(flags); + + /* Start counter exactly on falling edge of update flag */ + while (CMOS_READ(RTC_REG_A) & RTC_UIP); + while (!(CMOS_READ(RTC_REG_A) & RTC_UIP)); + + /* Start r4k counter. */ + write_c0_count(0); + + /* Read counter exactly on falling edge of update flag */ + while (CMOS_READ(RTC_REG_A) & RTC_UIP); + while (!(CMOS_READ(RTC_REG_A) & RTC_UIP)); + + mips_hpt_frequency = read_c0_count(); + + /* restore interrupts */ + local_irq_restore(flags); + + return (mips_hpt_frequency / HZ); +} + +static unsigned long +it8172_rtc_get_time(void) +{ + unsigned int year, mon, day, hour, min, sec; + unsigned int flags; + + /* avoid update-in-progress. */ + for (;;) { + local_irq_save(flags); + if (! (CMOS_READ(RTC_REG_A) & RTC_UIP)) + break; + /* don't hold intr closed all the time */ + local_irq_restore(flags); + } + + /* Read regs. */ + sec = hw_to_bin(CMOS_READ(RTC_SECONDS)); + min = hw_to_bin(CMOS_READ(RTC_MINUTES)); + hour = hour_hw_to_bin(CMOS_READ(RTC_HOURS)); + day = hw_to_bin(CMOS_READ(RTC_DAY_OF_MONTH)); + mon = hw_to_bin(CMOS_READ(RTC_MONTH)); + year = hw_to_bin(CMOS_READ(RTC_YEAR)) + + hw_to_bin(*rtc_century_reg) * 100; + + /* restore interrupts */ + local_irq_restore(flags); + + return mktime(year, mon, day, hour, min, sec); +} + +static int +it8172_rtc_set_time(unsigned long t) +{ + struct rtc_time tm; + unsigned int flags; + + /* convert */ + to_tm(t, &tm); + + /* avoid update-in-progress. */ + for (;;) { + local_irq_save(flags); + if (! (CMOS_READ(RTC_REG_A) & RTC_UIP)) + break; + /* don't hold intr closed all the time */ + local_irq_restore(flags); + } + + *rtc_century_reg = bin_to_hw(tm.tm_year/100); + CMOS_WRITE(bin_to_hw(tm.tm_sec), RTC_SECONDS); + CMOS_WRITE(bin_to_hw(tm.tm_min), RTC_MINUTES); + CMOS_WRITE(hour_bin_to_hw(tm.tm_hour), RTC_HOURS); + CMOS_WRITE(bin_to_hw(tm.tm_mday), RTC_DAY_OF_MONTH); + CMOS_WRITE(bin_to_hw(tm.tm_mon+1), RTC_MONTH); /* tm_mon starts from 0 */ + CMOS_WRITE(bin_to_hw(tm.tm_year%100), RTC_YEAR); + + /* restore interrupts */ + local_irq_restore(flags); + + return 0; +} + +void __init it8172_time_init(void) +{ + unsigned int est_freq, flags; + + local_irq_save(flags); + + saved_control = CMOS_READ(RTC_CONTROL); + + printk("calculating r4koff... "); + r4k_offset = cal_r4koff(); + printk("%08lx(%d)\n", r4k_offset, (int) r4k_offset); + + est_freq = 2*r4k_offset*HZ; + est_freq += 5000; /* round */ + est_freq -= est_freq%10000; + printk("CPU frequency %d.%02d MHz\n", est_freq/1000000, + (est_freq%1000000)*100/1000000); + + local_irq_restore(flags); + + rtc_get_time = it8172_rtc_get_time; + rtc_set_time = it8172_rtc_set_time; +} + +#define ALLINTS (IE_IRQ0 | IE_IRQ1 | IE_IRQ2 | IE_IRQ3 | IE_IRQ4 | IE_IRQ5) +void __init it8172_timer_setup(struct irqaction *irq) +{ + puts("timer_setup\n"); + put32(NR_IRQS); + puts(""); + /* we are using the cpu counter for timer interrupts */ + setup_irq(MIPS_CPU_TIMER_IRQ, irq); + + /* to generate the first timer interrupt */ + r4k_cur = (read_c0_count() + r4k_offset); + write_c0_compare(r4k_cur); + set_c0_status(ALLINTS); +} |
