1/*
2 * include/asm-generic/rtc.h
3 *
4 * Author: Tom Rini <trini@mvista.com>
5 *
6 * Based on:
7 * drivers/char/rtc.c
8 *
9 * Please read the COPYING file for all license details.
10 */
11
12#ifndef __ASM_RTC_H__
13#define __ASM_RTC_H__
14
15#ifdef __KERNEL__
16
17#include <linux/mc146818rtc.h>
18#include <linux/rtc.h>
19#include <linux/bcd.h>
20
21#define RTC_PIE 0x40		/* periodic interrupt enable */
22#define RTC_AIE 0x20		/* alarm interrupt enable */
23#define RTC_UIE 0x10		/* update-finished interrupt enable */
24
25/* some dummy definitions */
26#define RTC_BATT_BAD 0x100	/* battery bad */
27#define RTC_SQWE 0x08		/* enable square-wave output */
28#define RTC_DM_BINARY 0x04	/* all time/date values are BCD if clear */
29#define RTC_24H 0x02		/* 24 hour mode - else hours bit 7 means pm */
30#define RTC_DST_EN 0x01	        /* auto switch DST - works f. USA only */
31
32/*
33 * Returns true if a clock update is in progress
34 */
35static inline unsigned char rtc_is_updating(void)
36{
37	unsigned char uip;
38
39	spin_lock_irq(&rtc_lock);
40	uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
41	spin_unlock_irq(&rtc_lock);
42	return uip;
43}
44
45static inline unsigned int get_rtc_time(struct rtc_time *time)
46{
47	unsigned long uip_watchdog = jiffies;
48	unsigned char ctrl;
49#ifdef CONFIG_MACH_DECSTATION
50	unsigned int real_year;
51#endif
52
53	/*
54	 * read RTC once any update in progress is done. The update
55	 * can take just over 2ms. We wait 10 to 20ms. There is no need to
56	 * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
57	 * If you need to know *exactly* when a second has started, enable
58	 * periodic update complete interrupts, (via ioctl) and then
59	 * immediately read /dev/rtc which will block until you get the IRQ.
60	 * Once the read clears, read the RTC time (again via ioctl). Easy.
61	 */
62
63	if (rtc_is_updating() != 0)
64		while (jiffies - uip_watchdog < 2*HZ/100) {
65			barrier();
66			cpu_relax();
67		}
68
69	/*
70	 * Only the values that we read from the RTC are set. We leave
71	 * tm_wday, tm_yday and tm_isdst untouched. Even though the
72	 * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
73	 * by the RTC when initially set to a non-zero value.
74	 */
75	spin_lock_irq(&rtc_lock);
76	time->tm_sec = CMOS_READ(RTC_SECONDS);
77	time->tm_min = CMOS_READ(RTC_MINUTES);
78	time->tm_hour = CMOS_READ(RTC_HOURS);
79	time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
80	time->tm_mon = CMOS_READ(RTC_MONTH);
81	time->tm_year = CMOS_READ(RTC_YEAR);
82#ifdef CONFIG_MACH_DECSTATION
83	real_year = CMOS_READ(RTC_DEC_YEAR);
84#endif
85	ctrl = CMOS_READ(RTC_CONTROL);
86	spin_unlock_irq(&rtc_lock);
87
88	if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
89	{
90		BCD_TO_BIN(time->tm_sec);
91		BCD_TO_BIN(time->tm_min);
92		BCD_TO_BIN(time->tm_hour);
93		BCD_TO_BIN(time->tm_mday);
94		BCD_TO_BIN(time->tm_mon);
95		BCD_TO_BIN(time->tm_year);
96	}
97
98#ifdef CONFIG_MACH_DECSTATION
99	time->tm_year += real_year - 72;
100#endif
101
102	/*
103	 * Account for differences between how the RTC uses the values
104	 * and how they are defined in a struct rtc_time;
105	 */
106	if (time->tm_year <= 69)
107		time->tm_year += 100;
108
109	time->tm_mon--;
110
111	return RTC_24H;
112}
113
114/* Set the current date and time in the real time clock. */
115static inline int set_rtc_time(struct rtc_time *time)
116{
117	unsigned long flags;
118	unsigned char mon, day, hrs, min, sec;
119	unsigned char save_control, save_freq_select;
120	unsigned int yrs;
121#ifdef CONFIG_MACH_DECSTATION
122	unsigned int real_yrs, leap_yr;
123#endif
124
125	yrs = time->tm_year;
126	mon = time->tm_mon + 1;   /* tm_mon starts at zero */
127	day = time->tm_mday;
128	hrs = time->tm_hour;
129	min = time->tm_min;
130	sec = time->tm_sec;
131
132	if (yrs > 255)	/* They are unsigned */
133		return -EINVAL;
134
135	spin_lock_irqsave(&rtc_lock, flags);
136#ifdef CONFIG_MACH_DECSTATION
137	real_yrs = yrs;
138	leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
139			!((yrs + 1900) % 400));
140	yrs = 72;
141
142	/*
143	 * We want to keep the year set to 73 until March
144	 * for non-leap years, so that Feb, 29th is handled
145	 * correctly.
146	 */
147	if (!leap_yr && mon < 3) {
148		real_yrs--;
149		yrs = 73;
150	}
151#endif
152	/* These limits and adjustments are independent of
153	 * whether the chip is in binary mode or not.
154	 */
155	if (yrs > 169) {
156		spin_unlock_irqrestore(&rtc_lock, flags);
157		return -EINVAL;
158	}
159
160	if (yrs >= 100)
161		yrs -= 100;
162
163	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
164	    || RTC_ALWAYS_BCD) {
165		BIN_TO_BCD(sec);
166		BIN_TO_BCD(min);
167		BIN_TO_BCD(hrs);
168		BIN_TO_BCD(day);
169		BIN_TO_BCD(mon);
170		BIN_TO_BCD(yrs);
171	}
172
173	save_control = CMOS_READ(RTC_CONTROL);
174	CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
175	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
176	CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
177
178#ifdef CONFIG_MACH_DECSTATION
179	CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
180#endif
181	CMOS_WRITE(yrs, RTC_YEAR);
182	CMOS_WRITE(mon, RTC_MONTH);
183	CMOS_WRITE(day, RTC_DAY_OF_MONTH);
184	CMOS_WRITE(hrs, RTC_HOURS);
185	CMOS_WRITE(min, RTC_MINUTES);
186	CMOS_WRITE(sec, RTC_SECONDS);
187
188	CMOS_WRITE(save_control, RTC_CONTROL);
189	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
190
191	spin_unlock_irqrestore(&rtc_lock, flags);
192
193	return 0;
194}
195
196static inline unsigned int get_rtc_ss(void)
197{
198	struct rtc_time h;
199
200	get_rtc_time(&h);
201	return h.tm_sec;
202}
203
204static inline int get_rtc_pll(struct rtc_pll_info *pll)
205{
206	return -EINVAL;
207}
208static inline int set_rtc_pll(struct rtc_pll_info *pll)
209{
210	return -EINVAL;
211}
212
213#endif /* __KERNEL__ */
214#endif /* __ASM_RTC_H__ */
215