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