arch/powerpc/kernel/rtas-rtc.c

   1 #include <linux/kernel.h>
   2 #include <linux/time.h>
   3 #include <linux/timer.h>
   4 #include <linux/init.h>
   5 #include <linux/rtc.h>
   6 #include <linux/delay.h>
   7 #include <linux/ratelimit.h>
   8 #include <asm/prom.h>
   9 #include <asm/rtas.h>
  10 #include <asm/time.h>
  11
  12
  13 #define MAX_RTC_WAIT 5000       /* 5 sec */
  14 #define RTAS_CLOCK_BUSY (-2)
  15 unsigned long __init rtas_get_boot_time(void)
  16 {
  17         int ret[8];
  18         int error;
  19         unsigned int wait_time;
  20         u64 max_wait_tb;
  21
  22         max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  23         do {
  24                 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
  25
  26                 wait_time = rtas_busy_delay_time(error);
  27                 if (wait_time) {
  28                         /* This is boot time so we spin. */
  29                         udelay(wait_time*1000);
  30                 }
  31         } while (wait_time && (get_tb() < max_wait_tb));
  32
  33         if (error != 0) {
  34                 printk_ratelimited(KERN_WARNING
  35                                    "error: reading the clock failed (%d)\n",
  36                                    error);
  37                 return 0;
  38         }
  39
  40         return mktime(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
  41 }
  42
  43 /* NOTE: get_rtc_time will get an error if executed in interrupt context
  44  * and if a delay is needed to read the clock.  In this case we just
  45  * silently return without updating rtc_tm.
  46  */
  47 void rtas_get_rtc_time(struct rtc_time *rtc_tm)
  48 {
  49         int ret[8];
  50         int error;
  51         unsigned int wait_time;
  52         u64 max_wait_tb;
  53
  54         max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  55         do {
  56                 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
  57
  58                 wait_time = rtas_busy_delay_time(error);
  59                 if (wait_time) {
  60                         if (in_interrupt()) {
  61                                 memset(rtc_tm, 0, sizeof(struct rtc_time));
  62                                 printk_ratelimited(KERN_WARNING
  63                                                    "error: reading clock "
  64                                                    "would delay interrupt\n");
  65                                 return; /* delay not allowed */
  66                         }
  67                         msleep(wait_time);
  68                 }
  69         } while (wait_time && (get_tb() < max_wait_tb));
  70
  71         if (error != 0) {
  72                 printk_ratelimited(KERN_WARNING
  73                                    "error: reading the clock failed (%d)\n",
  74                                    error);
  75                 return;
  76         }
  77
  78         rtc_tm->tm_sec = ret[5];
  79         rtc_tm->tm_min = ret[4];
  80         rtc_tm->tm_hour = ret[3];
  81         rtc_tm->tm_mday = ret[2];
  82         rtc_tm->tm_mon = ret[1] - 1;
  83         rtc_tm->tm_year = ret[0] - 1900;
  84 }
  85
  86 int rtas_set_rtc_time(struct rtc_time *tm)
  87 {
  88         int error, wait_time;
  89         u64 max_wait_tb;
  90
  91         max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  92         do {
  93                 error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
  94                                   tm->tm_year + 1900, tm->tm_mon + 1,
  95                                   tm->tm_mday, tm->tm_hour, tm->tm_min,
  96                                   tm->tm_sec, 0);
  97
  98                 wait_time = rtas_busy_delay_time(error);
  99                 if (wait_time) {
 100                         if (in_interrupt())
 101                                 return 1;       /* probably decrementer */
 102                         msleep(wait_time);
 103                 }
 104         } while (wait_time && (get_tb() < max_wait_tb));
 105
 106         if (error != 0)
 107                 printk_ratelimited(KERN_WARNING
 108                                    "error: setting the clock failed (%d)\n",
 109                                    error);
 110
 111         return 0;
 112 }