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linux
1/*
2 * inclue/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 char mon, day, hrs, min, sec;
118 unsigned char save_control, save_freq_select;
119 unsigned int yrs;
120#ifdef CONFIG_MACH_DECSTATION
121 unsigned int real_yrs, leap_yr;
122#endif
123
124 yrs = time->tm_year;
125 mon = time->tm_mon + 1; /* tm_mon starts at zero */
126 day = time->tm_mday;
127 hrs = time->tm_hour;
128 min = time->tm_min;
129 sec = time->tm_sec;
130
131 if (yrs > 255) /* They are unsigned */
132 return -EINVAL;
133
134 spin_lock_irq(&rtc_lock);
135#ifdef CONFIG_MACH_DECSTATION
136 real_yrs = yrs;
137 leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
138 !((yrs + 1900) % 400));
139 yrs = 72;
140
141 /*
142 * We want to keep the year set to 73 until March
143 * for non-leap years, so that Feb, 29th is handled
144 * correctly.
145 */
146 if (!leap_yr && mon < 3) {
147 real_yrs--;
148 yrs = 73;
149 }
150#endif
151 /* These limits and adjustments are independent of
152 * whether the chip is in binary mode or not.
153 */
154 if (yrs > 169) {
155 spin_unlock_irq(&rtc_lock);
156 return -EINVAL;
157 }
158
159 if (yrs >= 100)
160 yrs -= 100;
161
162 if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
163 || RTC_ALWAYS_BCD) {
164 BIN_TO_BCD(sec);
165 BIN_TO_BCD(min);
166 BIN_TO_BCD(hrs);
167 BIN_TO_BCD(day);
168 BIN_TO_BCD(mon);
169 BIN_TO_BCD(yrs);
170 }
171
172 save_control = CMOS_READ(RTC_CONTROL);
173 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
174 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
175 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
176
177#ifdef CONFIG_MACH_DECSTATION
178 CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
179#endif
180 CMOS_WRITE(yrs, RTC_YEAR);
181 CMOS_WRITE(mon, RTC_MONTH);
182 CMOS_WRITE(day, RTC_DAY_OF_MONTH);
183 CMOS_WRITE(hrs, RTC_HOURS);
184 CMOS_WRITE(min, RTC_MINUTES);
185 CMOS_WRITE(sec, RTC_SECONDS);
186
187 CMOS_WRITE(save_control, RTC_CONTROL);
188 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
189
190 spin_unlock_irq(&rtc_lock);
191
192 return 0;
193}
194
195static inline unsigned int get_rtc_ss(void)
196{
197 struct rtc_time h;
198
199 get_rtc_time(&h);
200 return h.tm_sec;
201}
202
203static inline int get_rtc_pll(struct rtc_pll_info *pll)
204{
205 return -EINVAL;
206}
207static inline int set_rtc_pll(struct rtc_pll_info *pll)
208{
209 return -EINVAL;
210}
211
212#endif /* __KERNEL__ */
213#endif /* __ASM_RTC_H__ */