include/asm-generic/rtc.h

   1 /*
   2  * include/asm-generic/rtc.h
   3  *
   4  * Author: Tom Rini <trini@mvista.com>
   5  *
   6  * Based on:
   7  * drivers/char/rtc.c
   8  *
   9  * Please read the COPYING file for all license details.
  10  */
  11
  12 #ifndef __ASM_RTC_H__
  13 #define __ASM_RTC_H__
  14
  15 #ifdef __KERNEL__
  16
  17 #include <linux/mc146818rtc.h>
  18 #include <linux/rtc.h>
  19 #include <linux/bcd.h>
  20
  21 #define RTC_PIE 0x40            /* periodic interrupt enable */
  22 #define RTC_AIE 0x20            /* alarm interrupt enable */
  23 #define RTC_UIE 0x10            /* update-finished interrupt enable */
  24
  25 /* some dummy definitions */
  26 #define RTC_BATT_BAD 0x100      /* battery bad */
  27 #define RTC_SQWE 0x08           /* enable square-wave output */
  28 #define RTC_DM_BINARY 0x04      /* all time/date values are BCD if clear */
  29 #define RTC_24H 0x02            /* 24 hour mode - else hours bit 7 means pm */
  30 #define RTC_DST_EN 0x01         /* auto switch DST - works f. USA only */
  31
  32 /*
  33  * Returns true if a clock update is in progress
  34  */
  35 static inline unsigned char rtc_is_updating(void)
  36 {
  37         unsigned char uip;
  38         unsigned long flags;
  39
  40         spin_lock_irqsave(&rtc_lock, flags);
  41         uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
  42         spin_unlock_irqrestore(&rtc_lock, flags);
  43         return uip;
  44 }
  45
  46 static inline unsigned int get_rtc_time(struct rtc_time *time)
  47 {
  48         unsigned long uip_watchdog = jiffies;
  49         unsigned char ctrl;
  50         unsigned long flags;
  51
  52 #ifdef CONFIG_MACH_DECSTATION
  53         unsigned int real_year;
  54 #endif
  55
  56         /*
  57          * read RTC once any update in progress is done. The update
  58          * can take just over 2ms. We wait 10 to 20ms. There is no need to
  59          * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
  60          * If you need to know *exactly* when a second has started, enable
  61          * periodic update complete interrupts, (via ioctl) and then
  62          * immediately read /dev/rtc which will block until you get the IRQ.
  63          * Once the read clears, read the RTC time (again via ioctl). Easy.
  64          */
  65
  66         if (rtc_is_updating() != 0)
  67                 while (jiffies - uip_watchdog < 2*HZ/100) {
  68                         barrier();
  69                         cpu_relax();
  70                 }
  71
  72         /*
  73          * Only the values that we read from the RTC are set. We leave
  74          * tm_wday, tm_yday and tm_isdst untouched. Even though the
  75          * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
  76          * by the RTC when initially set to a non-zero value.
  77          */
  78         spin_lock_irqsave(&rtc_lock, flags);
  79         time->tm_sec = CMOS_READ(RTC_SECONDS);
  80         time->tm_min = CMOS_READ(RTC_MINUTES);
  81         time->tm_hour = CMOS_READ(RTC_HOURS);
  82         time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
  83         time->tm_mon = CMOS_READ(RTC_MONTH);
  84         time->tm_year = CMOS_READ(RTC_YEAR);
  85 #ifdef CONFIG_MACH_DECSTATION
  86         real_year = CMOS_READ(RTC_DEC_YEAR);
  87 #endif
  88         ctrl = CMOS_READ(RTC_CONTROL);
  89         spin_unlock_irqrestore(&rtc_lock, flags);
  90
  91         if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
  92         {
  93                 BCD_TO_BIN(time->tm_sec);
  94                 BCD_TO_BIN(time->tm_min);
  95                 BCD_TO_BIN(time->tm_hour);
  96                 BCD_TO_BIN(time->tm_mday);
  97                 BCD_TO_BIN(time->tm_mon);
  98                 BCD_TO_BIN(time->tm_year);
  99         }
 100
 101 #ifdef CONFIG_MACH_DECSTATION
 102         time->tm_year += real_year - 72;
 103 #endif
 104
 105         /*
 106          * Account for differences between how the RTC uses the values
 107          * and how they are defined in a struct rtc_time;
 108          */
 109         if (time->tm_year <= 69)
 110                 time->tm_year += 100;
 111
 112         time->tm_mon--;
 113
 114         return RTC_24H;
 115 }
 116
 117 /* Set the current date and time in the real time clock. */
 118 static inline int set_rtc_time(struct rtc_time *time)
 119 {
 120         unsigned long flags;
 121         unsigned char mon, day, hrs, min, sec;
 122         unsigned char save_control, save_freq_select;
 123         unsigned int yrs;
 124 #ifdef CONFIG_MACH_DECSTATION
 125         unsigned int real_yrs, leap_yr;
 126 #endif
 127
 128         yrs = time->tm_year;
 129         mon = time->tm_mon + 1;   /* tm_mon starts at zero */
 130         day = time->tm_mday;
 131         hrs = time->tm_hour;
 132         min = time->tm_min;
 133         sec = time->tm_sec;
 134
 135         if (yrs > 255)  /* They are unsigned */
 136                 return -EINVAL;
 137
 138         spin_lock_irqsave(&rtc_lock, flags);
 139 #ifdef CONFIG_MACH_DECSTATION
 140         real_yrs = yrs;
 141         leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
 142                         !((yrs + 1900) % 400));
 143         yrs = 72;
 144
 145         /*
 146          * We want to keep the year set to 73 until March
 147          * for non-leap years, so that Feb, 29th is handled
 148          * correctly.
 149          */
 150         if (!leap_yr && mon < 3) {
 151                 real_yrs--;
 152                 yrs = 73;
 153         }
 154 #endif
 155         /* These limits and adjustments are independent of
 156          * whether the chip is in binary mode or not.
 157          */
 158         if (yrs > 169) {
 159                 spin_unlock_irqrestore(&rtc_lock, flags);
 160                 return -EINVAL;
 161         }
 162
 163         if (yrs >= 100)
 164                 yrs -= 100;
 165
 166         if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
 167             || RTC_ALWAYS_BCD) {
 168                 BIN_TO_BCD(sec);
 169                 BIN_TO_BCD(min);
 170                 BIN_TO_BCD(hrs);
 171                 BIN_TO_BCD(day);
 172                 BIN_TO_BCD(mon);
 173                 BIN_TO_BCD(yrs);
 174         }
 175
 176         save_control = CMOS_READ(RTC_CONTROL);
 177         CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
 178         save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
 179         CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 180
 181 #ifdef CONFIG_MACH_DECSTATION
 182         CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
 183 #endif
 184         CMOS_WRITE(yrs, RTC_YEAR);
 185         CMOS_WRITE(mon, RTC_MONTH);
 186         CMOS_WRITE(day, RTC_DAY_OF_MONTH);
 187         CMOS_WRITE(hrs, RTC_HOURS);
 188         CMOS_WRITE(min, RTC_MINUTES);
 189         CMOS_WRITE(sec, RTC_SECONDS);
 190
 191         CMOS_WRITE(save_control, RTC_CONTROL);
 192         CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
 193
 194         spin_unlock_irqrestore(&rtc_lock, flags);
 195
 196         return 0;
 197 }
 198
 199 static inline unsigned int get_rtc_ss(void)
 200 {
 201         struct rtc_time h;
 202
 203         get_rtc_time(&h);
 204         return h.tm_sec;
 205 }
 206
 207 static inline int get_rtc_pll(struct rtc_pll_info *pll)
 208 {
 209         return -EINVAL;
 210 }
 211 static inline int set_rtc_pll(struct rtc_pll_info *pll)
 212 {
 213         return -EINVAL;
 214 }
 215
 216 #endif /* __KERNEL__ */
 217 #endif /* __ASM_RTC_H__ */