opal-rtc.c

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/*
 * PowerNV Real Time Clock.
 *
 * Copyright 2011 IBM Corp.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */


#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/bcd.h>
#include <linux/rtc.h>
#include <linux/delay.h>

#include <asm/opal.h>
#include <asm/firmware.h>

static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
{
    tm->tm_year = ((bcd2bin(y_m_d >> 24) * 100) +
               bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
    tm->tm_mon  = bcd2bin((y_m_d >> 8) & 0xff) - 1;
    tm->tm_mday = bcd2bin(y_m_d & 0xff);
    tm->tm_hour = bcd2bin((h_m_s_ms >> 56) & 0xff);
    tm->tm_min  = bcd2bin((h_m_s_ms >> 48) & 0xff);
    tm->tm_sec  = bcd2bin((h_m_s_ms >> 40) & 0xff);

        GregorianDay(tm);
}

unsigned long __init opal_get_boot_time(void)
{
    struct rtc_time tm;
    u32 y_m_d;
    u64 h_m_s_ms;
    long rc = OPAL_BUSY;

    while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
        rc = opal_rtc_read(&y_m_d, &h_m_s_ms);
        if (rc == OPAL_BUSY_EVENT)
            opal_poll_events(NULL);
        else
            mdelay(10);
    }
    if (rc != OPAL_SUCCESS)
        return 0;
    opal_to_tm(y_m_d, h_m_s_ms, &tm);
    return mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
              tm.tm_hour, tm.tm_min, tm.tm_sec);
}

void opal_get_rtc_time(struct rtc_time *tm)
{
    long rc = OPAL_BUSY;
    u32 y_m_d;
    u64 h_m_s_ms;

    while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
        rc = opal_rtc_read(&y_m_d, &h_m_s_ms);
        if (rc == OPAL_BUSY_EVENT)
            opal_poll_events(NULL);
        else
            mdelay(10);
    }
    if (rc != OPAL_SUCCESS)
        return;
    opal_to_tm(y_m_d, h_m_s_ms, tm);
}

int opal_set_rtc_time(struct rtc_time *tm)
{
    long rc = OPAL_BUSY;
    u32 y_m_d = 0;
    u64 h_m_s_ms = 0;

    y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) / 100)) << 24;
    y_m_d |= ((u32)bin2bcd((tm->tm_year + 1900) % 100)) << 16;
    y_m_d |= ((u32)bin2bcd((tm->tm_mon + 1))) << 8;
    y_m_d |= ((u32)bin2bcd(tm->tm_mday));

    h_m_s_ms |= ((u64)bin2bcd(tm->tm_hour)) << 56;
    h_m_s_ms |= ((u64)bin2bcd(tm->tm_min)) << 48;
    h_m_s_ms |= ((u64)bin2bcd(tm->tm_sec)) << 40;

    while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
        rc = opal_rtc_write(y_m_d, h_m_s_ms);
        if (rc == OPAL_BUSY_EVENT)
            opal_poll_events(NULL);
        else
            mdelay(10);
    }
    return rc == OPAL_SUCCESS ? 0 : -EIO;
}