1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * PowerNV Real Time Clock.
4 *
5 * Copyright 2011 IBM Corp.
6 */
7
8
9#include <linux/kernel.h>
10#include <linux/time.h>
11#include <linux/bcd.h>
12#include <linux/rtc.h>
13#include <linux/delay.h>
14#include <linux/of.h>
15#include <linux/of_platform.h>
16#include <linux/platform_device.h>
17
18#include <asm/opal.h>
19#include <asm/firmware.h>
20#include <asm/machdep.h>
21
22static void __init 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	tm->tm_wday     = -1;
32}
33
34time64_t __init opal_get_boot_time(void)
35{
36	struct rtc_time tm;
37	u32 y_m_d;
38	u64 h_m_s_ms;
39	__be32 __y_m_d;
40	__be64 __h_m_s_ms;
41	long rc = OPAL_BUSY;
42
43	if (!opal_check_token(OPAL_RTC_READ))
44		return 0;
45
46	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
47		rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
48		if (rc == OPAL_BUSY_EVENT) {
49			mdelay(OPAL_BUSY_DELAY_MS);
50			opal_poll_events(NULL);
51		} else if (rc == OPAL_BUSY) {
52			mdelay(OPAL_BUSY_DELAY_MS);
53		}
54	}
55	if (rc != OPAL_SUCCESS)
56		return 0;
57
58	y_m_d = be32_to_cpu(__y_m_d);
59	h_m_s_ms = be64_to_cpu(__h_m_s_ms);
60	opal_to_tm(y_m_d, h_m_s_ms, &tm);
61	return rtc_tm_to_time64(&tm);
62}
63
64static __init int opal_time_init(void)
65{
66	struct platform_device *pdev;
67	struct device_node *rtc;
68
69	rtc = of_find_node_by_path("/ibm,opal/rtc");
70	if (rtc) {
71		pdev = of_platform_device_create(rtc, "opal-rtc", NULL);
72		of_node_put(rtc);
73	} else {
74		if (opal_check_token(OPAL_RTC_READ) ||
75		    opal_check_token(OPAL_READ_TPO))
76			pdev = platform_device_register_simple("opal-rtc", -1,
77							       NULL, 0);
78		else
79			return -ENODEV;
80	}
81
82	return PTR_ERR_OR_ZERO(pdev);
83}
84machine_subsys_initcall(powernv, opal_time_init);
85