LXR linux/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#include <linux/platform_device.h>
  19#include <linux/of_platform.h>
  20
  21#include <asm/opal.h>
  22#include <asm/firmware.h>
  23#include <asm/machdep.h>
  24
  25static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
  26{
  27        tm->tm_year     = ((bcd2bin(y_m_d >> 24) * 100) +
  28                           bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
  29        tm->tm_mon      = bcd2bin((y_m_d >> 8) & 0xff) - 1;
  30        tm->tm_mday     = bcd2bin(y_m_d & 0xff);
  31        tm->tm_hour     = bcd2bin((h_m_s_ms >> 56) & 0xff);
  32        tm->tm_min      = bcd2bin((h_m_s_ms >> 48) & 0xff);
  33        tm->tm_sec      = bcd2bin((h_m_s_ms >> 40) & 0xff);
  34        tm->tm_wday     = -1;
  35}
  36
  37unsigned long __init opal_get_boot_time(void)
  38{
  39        struct rtc_time tm;
  40        u32 y_m_d;
  41        u64 h_m_s_ms;
  42        __be32 __y_m_d;
  43        __be64 __h_m_s_ms;
  44        long rc = OPAL_BUSY;
  45
  46        if (!opal_check_token(OPAL_RTC_READ))
  47                return 0;
  48
  49        while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  50                rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
  51                if (rc == OPAL_BUSY_EVENT)
  52                        opal_poll_events(NULL);
  53                else if (rc == OPAL_BUSY)
  54                        mdelay(10);
  55        }
  56        if (rc != OPAL_SUCCESS)
  57                return 0;
  58
  59        y_m_d = be32_to_cpu(__y_m_d);
  60        h_m_s_ms = be64_to_cpu(__h_m_s_ms);
  61        opal_to_tm(y_m_d, h_m_s_ms, &tm);
  62        return mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
  63                      tm.tm_hour, tm.tm_min, tm.tm_sec);
  64}
  65
  66static __init int opal_time_init(void)
  67{
  68        struct platform_device *pdev;
  69        struct device_node *rtc;
  70
  71        rtc = of_find_node_by_path("/ibm,opal/rtc");
  72        if (rtc) {
  73                pdev = of_platform_device_create(rtc, "opal-rtc", NULL);
  74                of_node_put(rtc);
  75        } else {
  76                if (opal_check_token(OPAL_RTC_READ) ||
  77                    opal_check_token(OPAL_READ_TPO))
  78                        pdev = platform_device_register_simple("opal-rtc", -1,
  79                                                               NULL, 0);
  80                else
  81                        return -ENODEV;
  82        }
  83
  84        return PTR_ERR_OR_ZERO(pdev);
  85}
  86machine_subsys_initcall(powernv, opal_time_init);
  87