1 /*
2 * RTC related functions
3 */
4 #include <linux/platform_device.h>
5 #include <linux/mc146818rtc.h>
6 #include <linux/acpi.h>
7 #include <linux/bcd.h>
8 #include <linux/export.h>
9 #include <linux/pnp.h>
10 #include <linux/of.h>
11
12 #include <asm/vsyscall.h>
13 #include <asm/x86_init.h>
14 #include <asm/time.h>
15 #include <asm/mrst.h>
16
17 #ifdef CONFIG_X86_32
18 /*
19 * This is a special lock that is owned by the CPU and holds the index
20 * register we are working with. It is required for NMI access to the
21 * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
22 */
23 volatile unsigned long cmos_lock;
24 EXPORT_SYMBOL(cmos_lock);
25 #endif /* CONFIG_X86_32 */
26
27 /* For two digit years assume time is always after that */
28 #define CMOS_YEARS_OFFS 2000
29
30 DEFINE_SPINLOCK(rtc_lock);
31 EXPORT_SYMBOL(rtc_lock);
32
33 /*
34 * In order to set the CMOS clock precisely, set_rtc_mmss has to be
35 * called 500 ms after the second nowtime has started, because when
36 * nowtime is written into the registers of the CMOS clock, it will
37 * jump to the next second precisely 500 ms later. Check the Motorola
38 * MC146818A or Dallas DS12887 data sheet for details.
39 *
40 * BUG: This routine does not handle hour overflow properly; it just
41 * sets the minutes. Usually you'll only notice that after reboot!
42 */
mach_set_rtc_mmss(unsigned long nowtime)43 int mach_set_rtc_mmss(unsigned long nowtime)
44 {
45 int real_seconds, real_minutes, cmos_minutes;
46 unsigned char save_control, save_freq_select;
47 unsigned long flags;
48 int retval = 0;
49
50 spin_lock_irqsave(&rtc_lock, flags);
51
52 /* tell the clock it's being set */
53 save_control = CMOS_READ(RTC_CONTROL);
54 CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
55
56 /* stop and reset prescaler */
57 save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
58 CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
59
60 cmos_minutes = CMOS_READ(RTC_MINUTES);
61 if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
62 cmos_minutes = bcd2bin(cmos_minutes);
63
64 /*
65 * since we're only adjusting minutes and seconds,
66 * don't interfere with hour overflow. This avoids
67 * messing with unknown time zones but requires your
68 * RTC not to be off by more than 15 minutes
69 */
70 real_seconds = nowtime % 60;
71 real_minutes = nowtime / 60;
72 /* correct for half hour time zone */
73 if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
74 real_minutes += 30;
75 real_minutes %= 60;
76
77 if (abs(real_minutes - cmos_minutes) < 30) {
78 if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
79 real_seconds = bin2bcd(real_seconds);
80 real_minutes = bin2bcd(real_minutes);
81 }
82 CMOS_WRITE(real_seconds, RTC_SECONDS);
83 CMOS_WRITE(real_minutes, RTC_MINUTES);
84 } else {
85 printk_once(KERN_NOTICE
86 "set_rtc_mmss: can't update from %d to %d\n",
87 cmos_minutes, real_minutes);
88 retval = -1;
89 }
90
91 /* The following flags have to be released exactly in this order,
92 * otherwise the DS12887 (popular MC146818A clone with integrated
93 * battery and quartz) will not reset the oscillator and will not
94 * update precisely 500 ms later. You won't find this mentioned in
95 * the Dallas Semiconductor data sheets, but who believes data
96 * sheets anyway ... -- Markus Kuhn
97 */
98 CMOS_WRITE(save_control, RTC_CONTROL);
99 CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
100
101 spin_unlock_irqrestore(&rtc_lock, flags);
102
103 return retval;
104 }
105
mach_get_cmos_time(void)106 unsigned long mach_get_cmos_time(void)
107 {
108 unsigned int status, year, mon, day, hour, min, sec, century = 0;
109 unsigned long flags;
110
111 spin_lock_irqsave(&rtc_lock, flags);
112
113 /*
114 * If UIP is clear, then we have >= 244 microseconds before
115 * RTC registers will be updated. Spec sheet says that this
116 * is the reliable way to read RTC - registers. If UIP is set
117 * then the register access might be invalid.
118 */
119 while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
120 cpu_relax();
121
122 sec = CMOS_READ(RTC_SECONDS);
123 min = CMOS_READ(RTC_MINUTES);
124 hour = CMOS_READ(RTC_HOURS);
125 day = CMOS_READ(RTC_DAY_OF_MONTH);
126 mon = CMOS_READ(RTC_MONTH);
127 year = CMOS_READ(RTC_YEAR);
128
129 #ifdef CONFIG_ACPI
130 if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
131 acpi_gbl_FADT.century)
132 century = CMOS_READ(acpi_gbl_FADT.century);
133 #endif
134
135 status = CMOS_READ(RTC_CONTROL);
136 WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY));
137
138 spin_unlock_irqrestore(&rtc_lock, flags);
139
140 if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) {
141 sec = bcd2bin(sec);
142 min = bcd2bin(min);
143 hour = bcd2bin(hour);
144 day = bcd2bin(day);
145 mon = bcd2bin(mon);
146 year = bcd2bin(year);
147 }
148
149 if (century) {
150 century = bcd2bin(century);
151 year += century * 100;
152 printk(KERN_INFO "Extended CMOS year: %d\n", century * 100);
153 } else
154 year += CMOS_YEARS_OFFS;
155
156 return mktime(year, mon, day, hour, min, sec);
157 }
158
159 /* Routines for accessing the CMOS RAM/RTC. */
rtc_cmos_read(unsigned char addr)160 unsigned char rtc_cmos_read(unsigned char addr)
161 {
162 unsigned char val;
163
164 lock_cmos_prefix(addr);
165 outb(addr, RTC_PORT(0));
166 val = inb(RTC_PORT(1));
167 lock_cmos_suffix(addr);
168
169 return val;
170 }
171 EXPORT_SYMBOL(rtc_cmos_read);
172
rtc_cmos_write(unsigned char val,unsigned char addr)173 void rtc_cmos_write(unsigned char val, unsigned char addr)
174 {
175 lock_cmos_prefix(addr);
176 outb(addr, RTC_PORT(0));
177 outb(val, RTC_PORT(1));
178 lock_cmos_suffix(addr);
179 }
180 EXPORT_SYMBOL(rtc_cmos_write);
181
update_persistent_clock(struct timespec now)182 int update_persistent_clock(struct timespec now)
183 {
184 return x86_platform.set_wallclock(now.tv_sec);
185 }
186
187 /* not static: needed by APM */
read_persistent_clock(struct timespec * ts)188 void read_persistent_clock(struct timespec *ts)
189 {
190 unsigned long retval;
191
192 retval = x86_platform.get_wallclock();
193
194 ts->tv_sec = retval;
195 ts->tv_nsec = 0;
196 }
197
native_read_tsc(void)198 unsigned long long native_read_tsc(void)
199 {
200 return __native_read_tsc();
201 }
202 EXPORT_SYMBOL(native_read_tsc);
203
204
205 static struct resource rtc_resources[] = {
206 [0] = {
207 .start = RTC_PORT(0),
208 .end = RTC_PORT(1),
209 .flags = IORESOURCE_IO,
210 },
211 [1] = {
212 .start = RTC_IRQ,
213 .end = RTC_IRQ,
214 .flags = IORESOURCE_IRQ,
215 }
216 };
217
218 static struct platform_device rtc_device = {
219 .name = "rtc_cmos",
220 .id = -1,
221 .resource = rtc_resources,
222 .num_resources = ARRAY_SIZE(rtc_resources),
223 };
224
add_rtc_cmos(void)225 static __init int add_rtc_cmos(void)
226 {
227 #ifdef CONFIG_PNP
228 static const char *ids[] __initconst =
229 { "PNP0b00", "PNP0b01", "PNP0b02", };
230 struct pnp_dev *dev;
231 struct pnp_id *id;
232 int i;
233
234 pnp_for_each_dev(dev) {
235 for (id = dev->id; id; id = id->next) {
236 for (i = 0; i < ARRAY_SIZE(ids); i++) {
237 if (compare_pnp_id(id, ids[i]) != 0)
238 return 0;
239 }
240 }
241 }
242 #endif
243 if (of_have_populated_dt())
244 return 0;
245
246 /* Intel MID platforms don't have ioport rtc */
247 if (mrst_identify_cpu())
248 return -ENODEV;
249
250 platform_device_register(&rtc_device);
251 dev_info(&rtc_device.dev,
252 "registered platform RTC device (no PNP device found)\n");
253
254 return 0;
255 }
256 device_initcall(add_rtc_cmos);
257