arch/powerpc/platforms/powernv/opal-rtc.c

   1 /*
   2  * PowerNV Real Time Clock.
   3  *
   4  * Copyright 2011 IBM Corp.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12
  13 #include <linux/kernel.h>
  14 #include <linux/time.h>
  15 #include <linux/bcd.h>
  16 #include <linux/rtc.h>
  17 #include <linux/delay.h>
  18
  19 #include <asm/opal.h>
  20 #include <asm/firmware.h>
  21
  22 static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
  23 {
  24         tm->tm_year     = ((bcd2bin(y_m_d >> 24) * 100) +
  25                            bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
  26         tm->tm_mon      = bcd2bin((y_m_d >> 8) & 0xff) - 1;
  27         tm->tm_mday     = bcd2bin(y_m_d & 0xff);
  28         tm->tm_hour     = bcd2bin((h_m_s_ms >> 56) & 0xff);
  29         tm->tm_min      = bcd2bin((h_m_s_ms >> 48) & 0xff);
  30         tm->tm_sec      = bcd2bin((h_m_s_ms >> 40) & 0xff);
  31
  32         GregorianDay(tm);
  33 }
  34
  35 unsigned long __init opal_get_boot_time(void)
  36 {
  37         struct rtc_time tm;
  38         u32 y_m_d;
  39         u64 h_m_s_ms;
  40         long rc = OPAL_BUSY;
  41
  42         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  43                 rc = opal_rtc_read(&y_m_d, &h_m_s_ms);
  44                 if (rc == OPAL_BUSY_EVENT)
  45                         opal_poll_events(NULL);
  46                 else
  47                         mdelay(10);
  48         }
  49         if (rc != OPAL_SUCCESS)
  50                 return 0;
  51         opal_to_tm(y_m_d, h_m_s_ms, &tm);
  52         return mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
  53                       tm.tm_hour, tm.tm_min, tm.tm_sec);
  54 }
  55
  56 void opal_get_rtc_time(struct rtc_time *tm)
  57 {
  58         long rc = OPAL_BUSY;
  59         u32 y_m_d;
  60         u64 h_m_s_ms;
  61
  62         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  63                 rc = opal_rtc_read(&y_m_d, &h_m_s_ms);
  64                 if (rc == OPAL_BUSY_EVENT)
  65                         opal_poll_events(NULL);
  66                 else
  67                         mdelay(10);
  68         }
  69         if (rc != OPAL_SUCCESS)
  70                 return;
  71         opal_to_tm(y_m_d, h_m_s_ms, tm);
  72 }
  73
  74 int opal_set_rtc_time(struct rtc_time *tm)
  75 {
  76         long rc = OPAL_BUSY;
  77         u32 y_m_d = 0;
  78         u64 h_m_s_ms = 0;
  79
  80         y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24;
  81         y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16;
  82         y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8;
  83         y_m_d |= ((u32)bin2bcd(tm->tm_mday));
  84
  85         h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56;
  86         h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48;
  87         h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40;
  88
  89         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  90                 rc = opal_rtc_write(y_m_d, h_m_s_ms);
  91                 if (rc == OPAL_BUSY_EVENT)
  92                         opal_poll_events(NULL);
  93                 else
  94                         mdelay(10);
  95         }
  96         return rc == OPAL_SUCCESS ? 0 : -EIO;
  97 }