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Commit | Line | Data |
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1da177e4 | 1 | /* |
fe599f9f | 2 | * RTC related functions |
1da177e4 | 3 | */ |
1122b134 | 4 | #include <linux/acpi.h> |
fe599f9f | 5 | #include <linux/bcd.h> |
1da177e4 | 6 | #include <linux/mc146818rtc.h> |
1da2e3d6 SS |
7 | #include <linux/platform_device.h> |
8 | #include <linux/pnp.h> | |
1da177e4 | 9 | |
fe599f9f | 10 | #include <asm/time.h> |
cdc7957d | 11 | #include <asm/vsyscall.h> |
1da177e4 | 12 | |
1122b134 | 13 | #ifdef CONFIG_X86_32 |
1122b134 TG |
14 | /* |
15 | * This is a special lock that is owned by the CPU and holds the index | |
16 | * register we are working with. It is required for NMI access to the | |
17 | * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details. | |
18 | */ | |
19 | volatile unsigned long cmos_lock = 0; | |
20 | EXPORT_SYMBOL(cmos_lock); | |
1122b134 TG |
21 | #endif |
22 | ||
b62576a2 AK |
23 | /* For two digit years assume time is always after that */ |
24 | #define CMOS_YEARS_OFFS 2000 | |
25 | ||
1122b134 TG |
26 | DEFINE_SPINLOCK(rtc_lock); |
27 | EXPORT_SYMBOL(rtc_lock); | |
28 | ||
1da177e4 LT |
29 | /* |
30 | * In order to set the CMOS clock precisely, set_rtc_mmss has to be | |
31 | * called 500 ms after the second nowtime has started, because when | |
32 | * nowtime is written into the registers of the CMOS clock, it will | |
33 | * jump to the next second precisely 500 ms later. Check the Motorola | |
34 | * MC146818A or Dallas DS12887 data sheet for details. | |
35 | * | |
36 | * BUG: This routine does not handle hour overflow properly; it just | |
37 | * sets the minutes. Usually you'll only notice that after reboot! | |
38 | */ | |
fe599f9f | 39 | int mach_set_rtc_mmss(unsigned long nowtime) |
1da177e4 LT |
40 | { |
41 | int retval = 0; | |
42 | int real_seconds, real_minutes, cmos_minutes; | |
43 | unsigned char save_control, save_freq_select; | |
44 | ||
1122b134 TG |
45 | /* tell the clock it's being set */ |
46 | save_control = CMOS_READ(RTC_CONTROL); | |
1da177e4 LT |
47 | CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL); |
48 | ||
1122b134 TG |
49 | /* stop and reset prescaler */ |
50 | save_freq_select = CMOS_READ(RTC_FREQ_SELECT); | |
1da177e4 LT |
51 | CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT); |
52 | ||
53 | cmos_minutes = CMOS_READ(RTC_MINUTES); | |
54 | if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) | |
55 | BCD_TO_BIN(cmos_minutes); | |
56 | ||
57 | /* | |
58 | * since we're only adjusting minutes and seconds, | |
59 | * don't interfere with hour overflow. This avoids | |
60 | * messing with unknown time zones but requires your | |
61 | * RTC not to be off by more than 15 minutes | |
62 | */ | |
63 | real_seconds = nowtime % 60; | |
64 | real_minutes = nowtime / 60; | |
1122b134 | 65 | /* correct for half hour time zone */ |
1da177e4 | 66 | if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) |
1122b134 | 67 | real_minutes += 30; |
1da177e4 LT |
68 | real_minutes %= 60; |
69 | ||
70 | if (abs(real_minutes - cmos_minutes) < 30) { | |
71 | if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { | |
72 | BIN_TO_BCD(real_seconds); | |
73 | BIN_TO_BCD(real_minutes); | |
74 | } | |
75 | CMOS_WRITE(real_seconds,RTC_SECONDS); | |
76 | CMOS_WRITE(real_minutes,RTC_MINUTES); | |
77 | } else { | |
78 | printk(KERN_WARNING | |
79 | "set_rtc_mmss: can't update from %d to %d\n", | |
80 | cmos_minutes, real_minutes); | |
81 | retval = -1; | |
82 | } | |
83 | ||
84 | /* The following flags have to be released exactly in this order, | |
85 | * otherwise the DS12887 (popular MC146818A clone with integrated | |
86 | * battery and quartz) will not reset the oscillator and will not | |
87 | * update precisely 500 ms later. You won't find this mentioned in | |
88 | * the Dallas Semiconductor data sheets, but who believes data | |
89 | * sheets anyway ... -- Markus Kuhn | |
90 | */ | |
91 | CMOS_WRITE(save_control, RTC_CONTROL); | |
92 | CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT); | |
93 | ||
94 | return retval; | |
95 | } | |
96 | ||
fe599f9f | 97 | unsigned long mach_get_cmos_time(void) |
1da177e4 | 98 | { |
068c9222 | 99 | unsigned int status, year, mon, day, hour, min, sec, century = 0; |
1122b134 TG |
100 | |
101 | /* | |
102 | * If UIP is clear, then we have >= 244 microseconds before | |
103 | * RTC registers will be updated. Spec sheet says that this | |
104 | * is the reliable way to read RTC - registers. If UIP is set | |
105 | * then the register access might be invalid. | |
106 | */ | |
107 | while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)) | |
108 | cpu_relax(); | |
109 | ||
110 | sec = CMOS_READ(RTC_SECONDS); | |
111 | min = CMOS_READ(RTC_MINUTES); | |
112 | hour = CMOS_READ(RTC_HOURS); | |
113 | day = CMOS_READ(RTC_DAY_OF_MONTH); | |
114 | mon = CMOS_READ(RTC_MONTH); | |
115 | year = CMOS_READ(RTC_YEAR); | |
116 | ||
45de7079 | 117 | #ifdef CONFIG_ACPI |
1122b134 TG |
118 | if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID && |
119 | acpi_gbl_FADT.century) | |
120 | century = CMOS_READ(acpi_gbl_FADT.century); | |
121 | #endif | |
122 | ||
068c9222 | 123 | status = CMOS_READ(RTC_CONTROL); |
45de7079 | 124 | WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY)); |
068c9222 AK |
125 | |
126 | if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) { | |
41623b06 MM |
127 | BCD_TO_BIN(sec); |
128 | BCD_TO_BIN(min); | |
129 | BCD_TO_BIN(hour); | |
130 | BCD_TO_BIN(day); | |
131 | BCD_TO_BIN(mon); | |
132 | BCD_TO_BIN(year); | |
133 | } | |
134 | ||
1122b134 TG |
135 | if (century) { |
136 | BCD_TO_BIN(century); | |
137 | year += century * 100; | |
138 | printk(KERN_INFO "Extended CMOS year: %d\n", century * 100); | |
b62576a2 | 139 | } else |
1122b134 | 140 | year += CMOS_YEARS_OFFS; |
1da177e4 LT |
141 | |
142 | return mktime(year, mon, day, hour, min, sec); | |
143 | } | |
144 | ||
fe599f9f TG |
145 | /* Routines for accessing the CMOS RAM/RTC. */ |
146 | unsigned char rtc_cmos_read(unsigned char addr) | |
147 | { | |
148 | unsigned char val; | |
149 | ||
150 | lock_cmos_prefix(addr); | |
04aaa7ba DR |
151 | outb(addr, RTC_PORT(0)); |
152 | val = inb(RTC_PORT(1)); | |
fe599f9f TG |
153 | lock_cmos_suffix(addr); |
154 | return val; | |
155 | } | |
156 | EXPORT_SYMBOL(rtc_cmos_read); | |
157 | ||
158 | void rtc_cmos_write(unsigned char val, unsigned char addr) | |
159 | { | |
160 | lock_cmos_prefix(addr); | |
04aaa7ba DR |
161 | outb(addr, RTC_PORT(0)); |
162 | outb(val, RTC_PORT(1)); | |
fe599f9f TG |
163 | lock_cmos_suffix(addr); |
164 | } | |
165 | EXPORT_SYMBOL(rtc_cmos_write); | |
166 | ||
167 | static int set_rtc_mmss(unsigned long nowtime) | |
168 | { | |
169 | int retval; | |
170 | unsigned long flags; | |
171 | ||
fe599f9f TG |
172 | spin_lock_irqsave(&rtc_lock, flags); |
173 | retval = set_wallclock(nowtime); | |
174 | spin_unlock_irqrestore(&rtc_lock, flags); | |
175 | ||
176 | return retval; | |
177 | } | |
178 | ||
179 | /* not static: needed by APM */ | |
180 | unsigned long read_persistent_clock(void) | |
181 | { | |
1122b134 | 182 | unsigned long retval, flags; |
fe599f9f TG |
183 | |
184 | spin_lock_irqsave(&rtc_lock, flags); | |
185 | retval = get_wallclock(); | |
186 | spin_unlock_irqrestore(&rtc_lock, flags); | |
187 | ||
188 | return retval; | |
189 | } | |
190 | ||
191 | int update_persistent_clock(struct timespec now) | |
192 | { | |
193 | return set_rtc_mmss(now.tv_sec); | |
194 | } | |
cdc7957d | 195 | |
92767af0 | 196 | unsigned long long native_read_tsc(void) |
cdc7957d | 197 | { |
92767af0 | 198 | return __native_read_tsc(); |
cdc7957d | 199 | } |
92767af0 IM |
200 | EXPORT_SYMBOL(native_read_tsc); |
201 | ||
1da2e3d6 SS |
202 | |
203 | static struct resource rtc_resources[] = { | |
204 | [0] = { | |
205 | .start = RTC_PORT(0), | |
206 | .end = RTC_PORT(1), | |
207 | .flags = IORESOURCE_IO, | |
208 | }, | |
209 | [1] = { | |
210 | .start = RTC_IRQ, | |
211 | .end = RTC_IRQ, | |
212 | .flags = IORESOURCE_IRQ, | |
213 | } | |
214 | }; | |
215 | ||
216 | static struct platform_device rtc_device = { | |
217 | .name = "rtc_cmos", | |
218 | .id = -1, | |
219 | .resource = rtc_resources, | |
220 | .num_resources = ARRAY_SIZE(rtc_resources), | |
221 | }; | |
222 | ||
223 | static __init int add_rtc_cmos(void) | |
224 | { | |
225 | #ifdef CONFIG_PNP | |
226 | if (!pnp_platform_devices) | |
227 | platform_device_register(&rtc_device); | |
228 | #else | |
229 | platform_device_register(&rtc_device); | |
230 | #endif /* CONFIG_PNP */ | |
231 | return 0; | |
232 | } | |
233 | device_initcall(add_rtc_cmos); |