LXR linux/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)
  15unsigned 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 */
  47void 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
  86int 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}
 113