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powerpc: time-of-day fixes for 32-bit CHRP systems
[mirror_ubuntu-bionic-kernel.git] / arch / powerpc / kernel / rtas-rtc.c
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1#include <linux/kernel.h>
2#include <linux/time.h>
3#include <linux/timer.h>
4#include <linux/init.h>
5#include <linux/rtc.h>
6#include <linux/delay.h>
7#include <asm/prom.h>
8#include <asm/rtas.h>
9#include <asm/time.h>
10
11
12#define MAX_RTC_WAIT 5000 /* 5 sec */
13#define RTAS_CLOCK_BUSY (-2)
14unsigned long __init rtas_get_boot_time(void)
15{
16 int ret[8];
17 int error, wait_time;
49e16b7b 18 u64 max_wait_tb;
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19
20 max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
21 do {
22 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
23 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
24 wait_time = rtas_extended_busy_delay_time(error);
25 /* This is boot time so we spin. */
26 udelay(wait_time*1000);
27 error = RTAS_CLOCK_BUSY;
28 }
29 } while (error == RTAS_CLOCK_BUSY && (get_tb() < max_wait_tb));
30
31 if (error != 0 && printk_ratelimit()) {
32 printk(KERN_WARNING "error: reading the clock failed (%d)\n",
33 error);
34 return 0;
35 }
36
37 return mktime(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
38}
39
40/* NOTE: get_rtc_time will get an error if executed in interrupt context
41 * and if a delay is needed to read the clock. In this case we just
42 * silently return without updating rtc_tm.
43 */
44void rtas_get_rtc_time(struct rtc_time *rtc_tm)
45{
46 int ret[8];
47 int error, wait_time;
49e16b7b 48 u64 max_wait_tb;
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49
50 max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
51 do {
52 error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
53 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
54 if (in_interrupt() && printk_ratelimit()) {
55 memset(&rtc_tm, 0, sizeof(struct rtc_time));
56 printk(KERN_WARNING "error: reading clock"
57 " would delay interrupt\n");
58 return; /* delay not allowed */
59 }
60 wait_time = rtas_extended_busy_delay_time(error);
61 msleep(wait_time);
62 error = RTAS_CLOCK_BUSY;
63 }
64 } while (error == RTAS_CLOCK_BUSY && (get_tb() < max_wait_tb));
65
66 if (error != 0 && printk_ratelimit()) {
67 printk(KERN_WARNING "error: reading the clock failed (%d)\n",
68 error);
69 return;
70 }
71
72 rtc_tm->tm_sec = ret[5];
73 rtc_tm->tm_min = ret[4];
74 rtc_tm->tm_hour = ret[3];
75 rtc_tm->tm_mday = ret[2];
76 rtc_tm->tm_mon = ret[1] - 1;
77 rtc_tm->tm_year = ret[0] - 1900;
78}
79
80int rtas_set_rtc_time(struct rtc_time *tm)
81{
82 int error, wait_time;
49e16b7b 83 u64 max_wait_tb;
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84
85 max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
86 do {
87 error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
88 tm->tm_year + 1900, tm->tm_mon + 1,
89 tm->tm_mday, tm->tm_hour, tm->tm_min,
90 tm->tm_sec, 0);
91 if (error == RTAS_CLOCK_BUSY || rtas_is_extended_busy(error)) {
92 if (in_interrupt())
93 return 1; /* probably decrementer */
94 wait_time = rtas_extended_busy_delay_time(error);
95 msleep(wait_time);
96 error = RTAS_CLOCK_BUSY;
97 }
98 } while (error == RTAS_CLOCK_BUSY && (get_tb() < max_wait_tb));
99
100 if (error != 0 && printk_ratelimit())
101 printk(KERN_WARNING "error: setting the clock failed (%d)\n",
102 error);
103
104 return 0;
105}