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) 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 */ 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 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