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: &tm);
61 return rtc_tm_to_time64(tm: &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(path: "/ibm,opal/rtc");
70 if (rtc) {
71 pdev = of_platform_device_create(np: rtc, bus_id: "opal-rtc", NULL);
72 of_node_put(node: rtc);
73 } else {
74 if (opal_check_token(OPAL_RTC_READ) ||
75 opal_check_token(OPAL_READ_TPO))
76 pdev = platform_device_register_simple(name: "opal-rtc", id: -1,
77 NULL, num: 0);
78 else
79 return -ENODEV;
80 }
81
82 return PTR_ERR_OR_ZERO(ptr: pdev);
83}
84machine_subsys_initcall(powernv, opal_time_init);
85

source code of linux/arch/powerpc/platforms/powernv/opal-rtc.c