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