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
35        GregorianDay(tm);
36}
37
38unsigned long __init opal_get_boot_time(void)
39{
40	struct rtc_time tm;
41	u32 y_m_d;
42	u64 h_m_s_ms;
43	__be32 __y_m_d;
44	__be64 __h_m_s_ms;
45	long rc = OPAL_BUSY;
46
47	if (!opal_check_token(OPAL_RTC_READ))
48		return 0;
49
50	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
51		rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
52		if (rc == OPAL_BUSY_EVENT)
53			opal_poll_events(NULL);
54		else
55			mdelay(10);
56	}
57	if (rc != OPAL_SUCCESS)
58		return 0;
59
60	y_m_d = be32_to_cpu(__y_m_d);
61	h_m_s_ms = be64_to_cpu(__h_m_s_ms);
62	opal_to_tm(y_m_d, h_m_s_ms, &tm);
63	return mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
64		      tm.tm_hour, tm.tm_min, tm.tm_sec);
65}
66
67static __init int opal_time_init(void)
68{
69	struct platform_device *pdev;
70	struct device_node *rtc;
71
72	rtc = of_find_node_by_path("/ibm,opal/rtc");
73	if (rtc) {
74		pdev = of_platform_device_create(rtc, "opal-rtc", NULL);
75		of_node_put(rtc);
76	} else {
77		if (opal_check_token(OPAL_RTC_READ) ||
78		    opal_check_token(OPAL_READ_TPO))
79			pdev = platform_device_register_simple("opal-rtc", -1,
80							       NULL, 0);
81		else
82			return -ENODEV;
83	}
84
85	return PTR_ERR_OR_ZERO(pdev);
86}
87machine_subsys_initcall(powernv, opal_time_init);
88