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
15time64_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(ret[0], ret[1], ret[2], ret[3], ret[4], 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 */
47void 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(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
86int 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(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