kernel/time.c

   1 /*
   2 ** Copyright 2003, Travis Geiselbrecht. All rights reserved.
   3 ** Distributed under the terms of the NewOS License.
   4 */
   5 #include <kernel/kernel.h>
   6 #include <kernel/debug.h>
   7 #include <kernel/time.h>
   8 #include <kernel/arch/time.h>
   9 #include <string.h>
  10
  11 // The 'rough' counter of system up time, accurate to the rate at
  12 // which the timer interrupts run (see TICK_RATE in timer.c).
  13 static bigtime_t sys_time;
  14
  15 // The delta of usecs that needs to be added to sys_time to get real time
  16 static bigtime_t real_time_delta;
  17
  18 // Any additional delta that might need to be added to the above two values
  19 // to get real time. (in case the RTC isn't in UTC)
  20 static bigtime_t tz_delta;
  21
  22 // The current name of the timezone, saved for all to see
  23 static char tz_name[SYS_MAX_NAME_LEN];
  24
  25 int time_init(kernel_args *ka)
  26 {
  27         dprintf("time_init: entry\n");
  28
  29         sys_time = 0;
  30         real_time_delta = 0;
  31         tz_delta = 0;
  32         strcpy(tz_name, "UTC");
  33
  34         return arch_time_init(ka);
  35 }
  36
  37 int time_init2(kernel_args *ka)
  38 {
  39         real_time_delta = arch_get_rtc_delta();
  40
  41         return 0;
  42 }
  43
  44 void time_tick(int tick_rate)
  45 {
  46         sys_time += tick_rate;
  47         arch_time_tick();
  48 }
  49
  50 bigtime_t system_time(void)
  51 {
  52         volatile bigtime_t *st = &sys_time;
  53         bigtime_t val;
  54
  55 retry:
  56         // read the system time, make sure we didn't get a partial read
  57         val = sys_time;
  58         if(val > *st)
  59                 goto retry;
  60
  61         // ask the architectural specific layer to give us a little better precision if it can
  62         val += arch_get_time_delta();
  63
  64         return val;
  65 }
  66
  67 bigtime_t system_time_lores(void)
  68 {
  69         volatile bigtime_t *st = &sys_time;
  70         bigtime_t val;
  71
  72 retry:
  73         // read the system time, make sure we didn't get a partial read
  74         val = sys_time;
  75         if(val > *st)
  76                 goto retry;
  77
  78         return val;
  79 }
  80
  81 bigtime_t local_time(void)
  82 {
  83         return system_time() + real_time_delta + tz_delta;
  84 }
  85