1// SPDX-License-Identifier: GPL-2.0
2/*
3 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
4 *
5 * Adapted for PowerPC (PReP) by Gary Thomas
6 * Modified by Cort Dougan (cort@cs.nmt.edu).
7 * Copied and modified from arch/i386/kernel/time.c
8 *
9 */
10#include <linux/errno.h>
11#include <linux/sched.h>
12#include <linux/kernel.h>
13#include <linux/param.h>
14#include <linux/string.h>
15#include <linux/mm.h>
16#include <linux/interrupt.h>
17#include <linux/time.h>
18#include <linux/timex.h>
19#include <linux/kernel_stat.h>
20#include <linux/mc146818rtc.h>
21#include <linux/init.h>
22#include <linux/bcd.h>
23#include <linux/ioport.h>
24#include <linux/of_address.h>
25
26#include <asm/io.h>
27#include <asm/nvram.h>
28#include <asm/sections.h>
29#include <asm/time.h>
30
31#include <platforms/chrp/chrp.h>
32
33#define NVRAM_AS0  0x74
34#define NVRAM_AS1  0x75
35#define NVRAM_DATA 0x77
36
37static int nvram_as1 = NVRAM_AS1;
38static int nvram_as0 = NVRAM_AS0;
39static int nvram_data = NVRAM_DATA;
40
41long __init chrp_time_init(void)
42{
43	struct device_node *rtcs;
44	struct resource r;
45	int base;
46
47	rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
48	if (rtcs == NULL)
49		rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
50	if (rtcs == NULL)
51		return 0;
52	if (of_address_to_resource(rtcs, 0, &r)) {
53		of_node_put(rtcs);
54		return 0;
55	}
56	of_node_put(rtcs);
57
58	base = r.start;
59	nvram_as1 = 0;
60	nvram_as0 = base;
61	nvram_data = base + 1;
62
63	return 0;
64}
65
66static int chrp_cmos_clock_read(int addr)
67{
68	if (nvram_as1 != 0)
69		outb(addr>>8, nvram_as1);
70	outb(addr, nvram_as0);
71	return (inb(nvram_data));
72}
73
74static void chrp_cmos_clock_write(unsigned long val, int addr)
75{
76	if (nvram_as1 != 0)
77		outb(addr>>8, nvram_as1);
78	outb(addr, nvram_as0);
79	outb(val, nvram_data);
80	return;
81}
82
83/*
84 * Set the hardware clock. -- Cort
85 */
86int chrp_set_rtc_time(struct rtc_time *tmarg)
87{
88	unsigned char save_control, save_freq_select;
89	struct rtc_time tm = *tmarg;
90
91	spin_lock(&rtc_lock);
92
93	save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
94
95	chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
96
97	save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
98
99	chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
100
101	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
102		tm.tm_sec = bin2bcd(tm.tm_sec);
103		tm.tm_min = bin2bcd(tm.tm_min);
104		tm.tm_hour = bin2bcd(tm.tm_hour);
105		tm.tm_mon = bin2bcd(tm.tm_mon);
106		tm.tm_mday = bin2bcd(tm.tm_mday);
107		tm.tm_year = bin2bcd(tm.tm_year);
108	}
109	chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
110	chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
111	chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
112	chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
113	chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
114	chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
115
116	/* The following flags have to be released exactly in this order,
117	 * otherwise the DS12887 (popular MC146818A clone with integrated
118	 * battery and quartz) will not reset the oscillator and will not
119	 * update precisely 500 ms later. You won't find this mentioned in
120	 * the Dallas Semiconductor data sheets, but who believes data
121	 * sheets anyway ...                           -- Markus Kuhn
122	 */
123	chrp_cmos_clock_write(save_control, RTC_CONTROL);
124	chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
125
126	spin_unlock(&rtc_lock);
127	return 0;
128}
129
130void chrp_get_rtc_time(struct rtc_time *tm)
131{
132	unsigned int year, mon, day, hour, min, sec;
133
134	do {
135		sec = chrp_cmos_clock_read(RTC_SECONDS);
136		min = chrp_cmos_clock_read(RTC_MINUTES);
137		hour = chrp_cmos_clock_read(RTC_HOURS);
138		day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
139		mon = chrp_cmos_clock_read(RTC_MONTH);
140		year = chrp_cmos_clock_read(RTC_YEAR);
141	} while (sec != chrp_cmos_clock_read(RTC_SECONDS));
142
143	if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
144		sec = bcd2bin(sec);
145		min = bcd2bin(min);
146		hour = bcd2bin(hour);
147		day = bcd2bin(day);
148		mon = bcd2bin(mon);
149		year = bcd2bin(year);
150	}
151	if (year < 70)
152		year += 100;
153	tm->tm_sec = sec;
154	tm->tm_min = min;
155	tm->tm_hour = hour;
156	tm->tm_mday = day;
157	tm->tm_mon = mon;
158	tm->tm_year = year;
159}
160