LXR linux/arch/powerpc/kernel/rtas-rtc.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/kernel.h>
   3#include <linux/time.h>
   4#include <linux/timer.h>
   5#include <linux/init.h>
   6#include <linux/rtc.h>
   7#include <linux/delay.h>
   8#include <linux/ratelimit.h>
   9#include <asm/prom.h>
  10#include <asm/rtas.h>
  11#include <asm/time.h>
  12
  13
  14#define MAX_RTC_WAIT 5000       /* 5 sec */
  15
  16time64_t __init rtas_get_boot_time(void)
  17{
  18        int ret[8];
  19        int error;
  20        unsigned int wait_time;
  21        u64 max_wait_tb;
  22
  23        max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  24        do {
  25                error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
  26
  27                wait_time = rtas_busy_delay_time(error);
  28                if (wait_time) {
  29                        /* This is boot time so we spin. */
  30                        udelay(wait_time*1000);
  31                }
  32        } while (wait_time && (get_tb() < max_wait_tb));
  33
  34        if (error != 0) {
  35                printk_ratelimited(KERN_WARNING
  36                                   "error: reading the clock failed (%d)\n",
  37                                   error);
  38                return 0;
  39        }
  40
  41        return mktime64(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
  42}
  43
  44/* NOTE: get_rtc_time will get an error if executed in interrupt context
  45 * and if a delay is needed to read the clock.  In this case we just
  46 * silently return without updating rtc_tm.
  47 */
  48void rtas_get_rtc_time(struct rtc_time *rtc_tm)
  49{
  50        int ret[8];
  51        int error;
  52        unsigned int wait_time;
  53        u64 max_wait_tb;
  54
  55        max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  56        do {
  57                error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
  58
  59                wait_time = rtas_busy_delay_time(error);
  60                if (wait_time) {
  61                        if (in_interrupt()) {
  62                                memset(rtc_tm, 0, sizeof(struct rtc_time));
  63                                printk_ratelimited(KERN_WARNING
  64                                                   "error: reading clock "
  65                                                   "would delay interrupt\n");
  66                                return; /* delay not allowed */
  67                        }
  68                        msleep(wait_time);
  69                }
  70        } while (wait_time && (get_tb() < max_wait_tb));
  71
  72        if (error != 0) {
  73                printk_ratelimited(KERN_WARNING
  74                                   "error: reading the clock failed (%d)\n",
  75                                   error);
  76                return;
  77        }
  78
  79        rtc_tm->tm_sec = ret[5];
  80        rtc_tm->tm_min = ret[4];
  81        rtc_tm->tm_hour = ret[3];
  82        rtc_tm->tm_mday = ret[2];
  83        rtc_tm->tm_mon = ret[1] - 1;
  84        rtc_tm->tm_year = ret[0] - 1900;
  85}
  86
  87int rtas_set_rtc_time(struct rtc_time *tm)
  88{
  89        int error, wait_time;
  90        u64 max_wait_tb;
  91
  92        max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
  93        do {
  94                error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
  95                                  tm->tm_year + 1900, tm->tm_mon + 1,
  96                                  tm->tm_mday, tm->tm_hour, tm->tm_min,
  97                                  tm->tm_sec, 0);
  98
  99                wait_time = rtas_busy_delay_time(error);
 100                if (wait_time) {
 101                        if (in_interrupt())
 102                                return 1;       /* probably decrementer */
 103                        msleep(wait_time);
 104                }
 105        } while (wait_time && (get_tb() < max_wait_tb));
 106
 107        if (error != 0)
 108                printk_ratelimited(KERN_WARNING
 109                                   "error: setting the clock failed (%d)\n",
 110                                   error);
 111
 112        return 0;
 113}
 114