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/platform_device.h>
15 #include <linux/of_platform.h>
16
17 #include <asm/opal.h>
18 #include <asm/firmware.h>
19 #include <asm/machdep.h>
20
opal_to_tm(u32 y_m_d,u64 h_m_s_ms,struct rtc_time * tm)21 static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
22 {
23 tm->tm_year = ((bcd2bin(y_m_d >> 24) * 100) +
24 bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
25 tm->tm_mon = bcd2bin((y_m_d >> 8) & 0xff) - 1;
26 tm->tm_mday = bcd2bin(y_m_d & 0xff);
27 tm->tm_hour = bcd2bin((h_m_s_ms >> 56) & 0xff);
28 tm->tm_min = bcd2bin((h_m_s_ms >> 48) & 0xff);
29 tm->tm_sec = bcd2bin((h_m_s_ms >> 40) & 0xff);
30 tm->tm_wday = -1;
31 }
32
opal_get_boot_time(void)33 time64_t __init opal_get_boot_time(void)
34 {
35 struct rtc_time tm;
36 u32 y_m_d;
37 u64 h_m_s_ms;
38 __be32 __y_m_d;
39 __be64 __h_m_s_ms;
40 long rc = OPAL_BUSY;
41
42 if (!opal_check_token(OPAL_RTC_READ))
43 return 0;
44
45 while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
46 rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
47 if (rc == OPAL_BUSY_EVENT) {
48 mdelay(OPAL_BUSY_DELAY_MS);
49 opal_poll_events(NULL);
50 } else if (rc == OPAL_BUSY) {
51 mdelay(OPAL_BUSY_DELAY_MS);
52 }
53 }
54 if (rc != OPAL_SUCCESS)
55 return 0;
56
57 y_m_d = be32_to_cpu(__y_m_d);
58 h_m_s_ms = be64_to_cpu(__h_m_s_ms);
59 opal_to_tm(y_m_d, h_m_s_ms, &tm);
60 return rtc_tm_to_time64(&tm);
61 }
62
opal_time_init(void)63 static __init int opal_time_init(void)
64 {
65 struct platform_device *pdev;
66 struct device_node *rtc;
67
68 rtc = of_find_node_by_path("/ibm,opal/rtc");
69 if (rtc) {
70 pdev = of_platform_device_create(rtc, "opal-rtc", NULL);
71 of_node_put(rtc);
72 } else {
73 if (opal_check_token(OPAL_RTC_READ) ||
74 opal_check_token(OPAL_READ_TPO))
75 pdev = platform_device_register_simple("opal-rtc", -1,
76 NULL, 0);
77 else
78 return -ENODEV;
79 }
80
81 return PTR_ERR_OR_ZERO(pdev);
82 }
83 machine_subsys_initcall(powernv, opal_time_init);
84