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Diffstat (limited to 'arch/arm/mach-footbridge/time.c')
| -rw-r--r-- | arch/arm/mach-footbridge/time.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/arch/arm/mach-footbridge/time.c b/arch/arm/mach-footbridge/time.c new file mode 100644 index 00000000000..2c64a0b0502 --- /dev/null +++ b/arch/arm/mach-footbridge/time.c @@ -0,0 +1,180 @@ +/* + * linux/include/asm-arm/arch-ebsa285/time.h + * + * Copyright (C) 1998 Russell King. + * Copyright (C) 1998 Phil Blundell + * + * CATS has a real-time clock, though the evaluation board doesn't. + * + * Changelog: + * 21-Mar-1998 RMK Created + * 27-Aug-1998 PJB CATS support + * 28-Dec-1998 APH Made leds optional + * 20-Jan-1999 RMK Started merge of EBSA285, CATS and NetWinder + * 16-Mar-1999 RMK More support for EBSA285-like machines with RTCs in + */ + +#define RTC_PORT(x) (rtc_base+(x)) +#define RTC_ALWAYS_BCD 0 + +#include <linux/timex.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/mc146818rtc.h> +#include <linux/bcd.h> + +#include <asm/hardware.h> +#include <asm/io.h> + +#include <asm/mach/time.h> +#include "common.h" + +static int rtc_base; + +static unsigned long __init get_isa_cmos_time(void) +{ + unsigned int year, mon, day, hour, min, sec; + int i; + + // check to see if the RTC makes sense..... + if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0) + return mktime(1970, 1, 1, 0, 0, 0); + + /* 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); +} + +static int set_isa_cmos_time(void) +{ + int retval = 0; + int real_seconds, real_minutes, cmos_minutes; + unsigned char save_control, save_freq_select; + unsigned long nowtime = xtime.tv_sec; + + save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */ + CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); + + save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */ + CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); + + cmos_minutes = CMOS_READ(RTC_MINUTES); + if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) + BCD_TO_BIN(cmos_minutes); + + /* + * since we're only adjusting minutes and seconds, + * don't interfere with hour overflow. This avoids + * messing with unknown time zones but requires your + * RTC not to be off by more than 15 minutes + */ + real_seconds = nowtime % 60; + real_minutes = nowtime / 60; + if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) + real_minutes += 30; /* correct for half hour time zone */ + real_minutes %= 60; + + if (abs(real_minutes - cmos_minutes) < 30) { + if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { + BIN_TO_BCD(real_seconds); + BIN_TO_BCD(real_minutes); + } + CMOS_WRITE(real_seconds,RTC_SECONDS); + CMOS_WRITE(real_minutes,RTC_MINUTES); + } else + retval = -1; + + /* 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 retval; +} + +void __init isa_rtc_init(void) +{ + if (machine_is_co285() || + machine_is_personal_server()) + /* + * Add-in 21285s shouldn't access the RTC + */ + rtc_base = 0; + else + rtc_base = 0x70; + + if (rtc_base) { + int reg_d, reg_b; + + /* + * Probe for the RTC. + */ + reg_d = CMOS_READ(RTC_REG_D); + + /* + * make sure the divider is set + */ + CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A); + + /* + * Set control reg B + * (24 hour mode, update enabled) + */ + reg_b = CMOS_READ(RTC_REG_B) & 0x7f; + reg_b |= 2; + CMOS_WRITE(reg_b, RTC_REG_B); + + if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ && + CMOS_READ(RTC_REG_B) == reg_b) { + struct timespec tv; + + /* + * We have a RTC. Check the battery + */ + if ((reg_d & 0x80) == 0) + printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n"); + + tv.tv_nsec = 0; + tv.tv_sec = get_isa_cmos_time(); + do_settimeofday(&tv); + set_rtc = set_isa_cmos_time; + } else + rtc_base = 0; + } +} |