release/src-rt-6.x/linux/linux-2.6/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;
  18         unsigned int wait_time;
  19         u64 max_wait_tb;
  20
  21         max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  22         do {
  23                 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
  24
  25                 wait_time = rtas_busy_delay_time(error);
  26                 if (wait_time) {
  27                         /* This is boot time so we spin. */
  28                         udelay(wait_time*1000);
  29                 }
  30         } while (wait_time && (get_tb() < max_wait_tb));
  31
  32         if (error != 0 && printk_ratelimit()) {
  33                 printk(KERN_WARNING "error: reading the clock failed (%d)\n",
  34                         error);
  35                 return 0;
  36         }
  37
  38         return mktime(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
  39 }
  40
  41 /* NOTE: get_rtc_time will get an error if executed in interrupt context
  42  * and if a delay is needed to read the clock.  In this case we just
  43  * silently return without updating rtc_tm.
  44  */
  45 void rtas_get_rtc_time(struct rtc_time *rtc_tm)
  46 {
  47         int ret[8];
  48         int error;
  49         unsigned int wait_time;
  50         u64 max_wait_tb;
  51
  52         max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  53         do {
  54                 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
  55
  56                 wait_time = rtas_busy_delay_time(error);
  57                 if (wait_time) {
  58                         if (in_interrupt() && printk_ratelimit()) {
  59                                 memset(rtc_tm, 0, sizeof(struct rtc_time));
  60                                 printk(KERN_WARNING "error: reading clock"
  61                                        " would delay interrupt\n");
  62                                 return; /* delay not allowed */
  63                         }
  64                         msleep(wait_time);
  65                 }
  66         } while (wait_time && (get_tb() < max_wait_tb));
  67
  68         if (error != 0 && printk_ratelimit()) {
  69                 printk(KERN_WARNING "error: reading the clock failed (%d)\n",
  70                        error);
  71                 return;
  72         }
  73
  74         rtc_tm->tm_sec = ret[5];
  75         rtc_tm->tm_min = ret[4];
  76         rtc_tm->tm_hour = ret[3];
  77         rtc_tm->tm_mday = ret[2];
  78         rtc_tm->tm_mon = ret[1] - 1;
  79         rtc_tm->tm_year = ret[0] - 1900;
  80 }
  81
  82 int rtas_set_rtc_time(struct rtc_time *tm)
  83 {
  84         int error, wait_time;
  85         u64 max_wait_tb;
  86
  87         max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  88         do {
  89                 error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
  90                                   tm->tm_year + 1900, tm->tm_mon + 1,
  91                                   tm->tm_mday, tm->tm_hour, tm->tm_min,
  92                                   tm->tm_sec, 0);
  93
  94                 wait_time = rtas_busy_delay_time(error);
  95                 if (wait_time) {
  96                         if (in_interrupt())
  97                                 return 1;       /* probably decrementer */
  98                         msleep(wait_time);
  99                 }
 100         } while (wait_time && (get_tb() < max_wait_tb));
 101
 102         if (error != 0 && printk_ratelimit())
 103                 printk(KERN_WARNING "error: setting the clock failed (%d)\n",
 104                        error);
 105
 106         return 0;
 107 }