1 /*
2 * RTC related functions
3 */
4 #include <linux/acpi.h>
5 #include <linux/bcd.h>
6 #include <linux/mc146818rtc.h>
7 #include <linux/platform_device.h>
8 #include <linux/pnp.h>
9
10 #include <asm/time.h>
11 #include <asm/vsyscall.h>
12
13 #ifdef CONFIG_X86_32
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);
21 #endif
22
23 /* For two digit years assume time is always after that */
24 #define CMOS_YEARS_OFFS 2000
25
26 DEFINE_SPINLOCK(rtc_lock);
27 EXPORT_SYMBOL(rtc_lock);
28
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 */
mach_set_rtc_mmss(unsigned long nowtime)39 int mach_set_rtc_mmss(unsigned long nowtime)
40 {
41 int retval = 0;
42 int real_seconds, real_minutes, cmos_minutes;
43 unsigned char save_control, save_freq_select;
44
45 /* tell the clock it's being set */
46 save_control = CMOS_READ(RTC_CONTROL);
47 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
48
49 /* stop and reset prescaler */
50 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
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 cmos_minutes = bcd2bin(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;
65 /* correct for half hour time zone */
66 if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
67 real_minutes += 30;
68 real_minutes %= 60;
69
70 if (abs(real_minutes - cmos_minutes) < 30) {
71 if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
72 real_seconds = bin2bcd(real_seconds);
73 real_minutes = bin2bcd(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
mach_get_cmos_time(void)97 unsigned long mach_get_cmos_time(void)
98 {
99 unsigned int status, year, mon, day, hour, min, sec, century = 0;
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
117 #ifdef CONFIG_ACPI
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
123 status = CMOS_READ(RTC_CONTROL);
124 WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY));
125
126 if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) {
127 sec = bcd2bin(sec);
128 min = bcd2bin(min);
129 hour = bcd2bin(hour);
130 day = bcd2bin(day);
131 mon = bcd2bin(mon);
132 year = bcd2bin(year);
133 }
134
135 if (century) {
136 century = bcd2bin(century);
137 year += century * 100;
138 printk(KERN_INFO "Extended CMOS year: %d\n", century * 100);
139 } else
140 year += CMOS_YEARS_OFFS;
141
142 return mktime(year, mon, day, hour, min, sec);
143 }
144
145 /* Routines for accessing the CMOS RAM/RTC. */
rtc_cmos_read(unsigned char addr)146 unsigned char rtc_cmos_read(unsigned char addr)
147 {
148 unsigned char val;
149
150 lock_cmos_prefix(addr);
151 outb(addr, RTC_PORT(0));
152 val = inb(RTC_PORT(1));
153 lock_cmos_suffix(addr);
154 return val;
155 }
156 EXPORT_SYMBOL(rtc_cmos_read);
157
rtc_cmos_write(unsigned char val,unsigned char addr)158 void rtc_cmos_write(unsigned char val, unsigned char addr)
159 {
160 lock_cmos_prefix(addr);
161 outb(addr, RTC_PORT(0));
162 outb(val, RTC_PORT(1));
163 lock_cmos_suffix(addr);
164 }
165 EXPORT_SYMBOL(rtc_cmos_write);
166
set_rtc_mmss(unsigned long nowtime)167 static int set_rtc_mmss(unsigned long nowtime)
168 {
169 int retval;
170 unsigned long flags;
171
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 */
read_persistent_clock(void)180 unsigned long read_persistent_clock(void)
181 {
182 unsigned long retval, flags;
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
update_persistent_clock(struct timespec now)191 int update_persistent_clock(struct timespec now)
192 {
193 return set_rtc_mmss(now.tv_sec);
194 }
195
native_read_tsc(void)196 unsigned long long native_read_tsc(void)
197 {
198 return __native_read_tsc();
199 }
200 EXPORT_SYMBOL(native_read_tsc);
201
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
add_rtc_cmos(void)223 static __init int add_rtc_cmos(void)
224 {
225 #ifdef CONFIG_PNP
226 static const char *ids[] __initconst =
227 { "PNP0b00", "PNP0b01", "PNP0b02", };
228 struct pnp_dev *dev;
229 struct pnp_id *id;
230 int i;
231
232 pnp_for_each_dev(dev) {
233 for (id = dev->id; id; id = id->next) {
234 for (i = 0; i < ARRAY_SIZE(ids); i++) {
235 if (compare_pnp_id(id, ids[i]) != 0)
236 return 0;
237 }
238 }
239 }
240 #endif
241
242 platform_device_register(&rtc_device);
243 dev_info(&rtc_device.dev,
244 "registered platform RTC device (no PNP device found)\n");
245 return 0;
246 }
247 device_initcall(add_rtc_cmos);
248