1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/time.h>
4 #include <linux/timer.h>
5 #include <linux/init.h>
6 #include <linux/rtc.h>
7 #include <linux/delay.h>
8 #include <linux/ratelimit.h>
9 #include <asm/prom.h>
10 #include <asm/rtas.h>
11 #include <asm/time.h>
12
13
14 #define MAX_RTC_WAIT 5000 /* 5 sec */
15 #define RTAS_CLOCK_BUSY (-2)
rtas_get_boot_time(void)16 time64_t __init rtas_get_boot_time(void)
17 {
18 int ret[8];
19 int error;
20 unsigned int wait_time;
21 u64 max_wait_tb;
22
23 max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
24 do {
25 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
26
27 wait_time = rtas_busy_delay_time(error);
28 if (wait_time) {
29 /* This is boot time so we spin. */
30 udelay(wait_time*1000);
31 }
32 } while (wait_time && (get_tb() < max_wait_tb));
33
34 if (error != 0) {
35 printk_ratelimited(KERN_WARNING
36 "error: reading the clock failed (%d)\n",
37 error);
38 return 0;
39 }
40
41 return mktime64(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
42 }
43
44 /* NOTE: get_rtc_time will get an error if executed in interrupt context
45 * and if a delay is needed to read the clock. In this case we just
46 * silently return without updating rtc_tm.
47 */
rtas_get_rtc_time(struct rtc_time * rtc_tm)48 void rtas_get_rtc_time(struct rtc_time *rtc_tm)
49 {
50 int ret[8];
51 int error;
52 unsigned int wait_time;
53 u64 max_wait_tb;
54
55 max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
56 do {
57 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
58
59 wait_time = rtas_busy_delay_time(error);
60 if (wait_time) {
61 if (in_interrupt()) {
62 memset(rtc_tm, 0, sizeof(struct rtc_time));
63 printk_ratelimited(KERN_WARNING
64 "error: reading clock "
65 "would delay interrupt\n");
66 return; /* delay not allowed */
67 }
68 msleep(wait_time);
69 }
70 } while (wait_time && (get_tb() < max_wait_tb));
71
72 if (error != 0) {
73 printk_ratelimited(KERN_WARNING
74 "error: reading the clock failed (%d)\n",
75 error);
76 return;
77 }
78
79 rtc_tm->tm_sec = ret[5];
80 rtc_tm->tm_min = ret[4];
81 rtc_tm->tm_hour = ret[3];
82 rtc_tm->tm_mday = ret[2];
83 rtc_tm->tm_mon = ret[1] - 1;
84 rtc_tm->tm_year = ret[0] - 1900;
85 }
86
rtas_set_rtc_time(struct rtc_time * tm)87 int rtas_set_rtc_time(struct rtc_time *tm)
88 {
89 int error, wait_time;
90 u64 max_wait_tb;
91
92 max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
93 do {
94 error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
95 tm->tm_year + 1900, tm->tm_mon + 1,
96 tm->tm_mday, tm->tm_hour, tm->tm_min,
97 tm->tm_sec, 0);
98
99 wait_time = rtas_busy_delay_time(error);
100 if (wait_time) {
101 if (in_interrupt())
102 return 1; /* probably decrementer */
103 msleep(wait_time);
104 }
105 } while (wait_time && (get_tb() < max_wait_tb));
106
107 if (error != 0)
108 printk_ratelimited(KERN_WARNING
109 "error: setting the clock failed (%d)\n",
110 error);
111
112 return 0;
113 }
114
