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         __be32 __y_m_d;
  41         __be64 __h_m_s_ms;
  42         long rc = OPAL_BUSY;
  43
  44         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  45                 rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
  46                 if (rc == OPAL_BUSY_EVENT)
  47                         opal_poll_events(NULL);
  48                 else
  49                         mdelay(10);
  50         }
  51         if (rc != OPAL_SUCCESS)
  52                 return 0;
  53         y_m_d = be32_to_cpu(__y_m_d);
  54         h_m_s_ms = be64_to_cpu(__h_m_s_ms);
  55         opal_to_tm(y_m_d, h_m_s_ms, &tm);
  56         return mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
  57                       tm.tm_hour, tm.tm_min, tm.tm_sec);
  58 }
  59
  60 void opal_get_rtc_time(struct rtc_time *tm)
  61 {
  62         long rc = OPAL_BUSY;
  63         u32 y_m_d;
  64         u64 h_m_s_ms;
  65         __be32 __y_m_d;
  66         __be64 __h_m_s_ms;
  67
  68         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  69                 rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
  70                 if (rc == OPAL_BUSY_EVENT)
  71                         opal_poll_events(NULL);
  72                 else
  73                         mdelay(10);
  74         }
  75         if (rc != OPAL_SUCCESS)
  76                 return;
  77         y_m_d = be32_to_cpu(__y_m_d);
  78         h_m_s_ms = be64_to_cpu(__h_m_s_ms);
  79         opal_to_tm(y_m_d, h_m_s_ms, tm);
  80 }
  81
  82 int opal_set_rtc_time(struct rtc_time *tm)
  83 {
  84         long rc = OPAL_BUSY;
  85         u32 y_m_d = 0;
  86         u64 h_m_s_ms = 0;
  87
  88         y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24;
  89         y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16;
  90         y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8;
  91         y_m_d |= ((u32)bin2bcd(tm->tm_mday));
  92
  93         h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56;
  94         h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48;
  95         h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40;
  96
  97         while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  98                 rc = opal_rtc_write(y_m_d, h_m_s_ms);
  99                 if (rc == OPAL_BUSY_EVENT)
 100                         opal_poll_events(NULL);
 101                 else
 102                         mdelay(10);
 103         }
 104         return rc == OPAL_SUCCESS ? 0 : -EIO;
 105 }