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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * RTC related functions
4 */
5#include <linux/platform_device.h>
6#include <linux/mc146818rtc.h>
7#include <linux/acpi.h>
8#include <linux/bcd.h>
9#include <linux/export.h>
10#include <linux/pnp.h>
11#include <linux/of.h>
12
13#include <asm/vsyscall.h>
14#include <asm/x86_init.h>
15#include <asm/time.h>
16#include <asm/intel-mid.h>
17#include <asm/setup.h>
18
19#ifdef CONFIG_X86_32
20/*
21 * This is a special lock that is owned by the CPU and holds the index
22 * register we are working with. It is required for NMI access to the
23 * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
24 */
25volatile unsigned long cmos_lock;
26EXPORT_SYMBOL(cmos_lock);
27#endif /* CONFIG_X86_32 */
28
29/* For two digit years assume time is always after that */
30#define CMOS_YEARS_OFFS 2000
31
32DEFINE_SPINLOCK(rtc_lock);
33EXPORT_SYMBOL(rtc_lock);
34
35/*
36 * In order to set the CMOS clock precisely, set_rtc_mmss has to be
37 * called 500 ms after the second nowtime has started, because when
38 * nowtime is written into the registers of the CMOS clock, it will
39 * jump to the next second precisely 500 ms later. Check the Motorola
40 * MC146818A or Dallas DS12887 data sheet for details.
41 */
42int mach_set_rtc_mmss(const struct timespec64 *now)
43{
44 unsigned long long nowtime = now->tv_sec;
45 struct rtc_time tm;
46 int retval = 0;
47
48 rtc_time64_to_tm(nowtime, &tm);
49 if (!rtc_valid_tm(&tm)) {
50 retval = mc146818_set_time(&tm);
51 if (retval)
52 printk(KERN_ERR "%s: RTC write failed with error %d\n",
53 __func__, retval);
54 } else {
55 printk(KERN_ERR
56 "%s: Invalid RTC value: write of %llx to RTC failed\n",
57 __func__, nowtime);
58 retval = -EINVAL;
59 }
60 return retval;
61}
62
63void mach_get_cmos_time(struct timespec64 *now)
64{
65 unsigned int status, year, mon, day, hour, min, sec, century = 0;
66 unsigned long flags;
67
68 /*
69 * If pm_trace abused the RTC as storage, set the timespec to 0,
70 * which tells the caller that this RTC value is unusable.
71 */
72 if (!pm_trace_rtc_valid()) {
73 now->tv_sec = now->tv_nsec = 0;
74 return;
75 }
76
77 spin_lock_irqsave(&rtc_lock, flags);
78
79 /*
80 * If UIP is clear, then we have >= 244 microseconds before
81 * RTC registers will be updated. Spec sheet says that this
82 * is the reliable way to read RTC - registers. If UIP is set
83 * then the register access might be invalid.
84 */
85 while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
86 cpu_relax();
87
88 sec = CMOS_READ(RTC_SECONDS);
89 min = CMOS_READ(RTC_MINUTES);
90 hour = CMOS_READ(RTC_HOURS);
91 day = CMOS_READ(RTC_DAY_OF_MONTH);
92 mon = CMOS_READ(RTC_MONTH);
93 year = CMOS_READ(RTC_YEAR);
94
95#ifdef CONFIG_ACPI
96 if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
97 acpi_gbl_FADT.century)
98 century = CMOS_READ(acpi_gbl_FADT.century);
99#endif
100
101 status = CMOS_READ(RTC_CONTROL);
102 WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY));
103
104 spin_unlock_irqrestore(&rtc_lock, flags);
105
106 if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) {
107 sec = bcd2bin(sec);
108 min = bcd2bin(min);
109 hour = bcd2bin(hour);
110 day = bcd2bin(day);
111 mon = bcd2bin(mon);
112 year = bcd2bin(year);
113 }
114
115 if (century) {
116 century = bcd2bin(century);
117 year += century * 100;
118 } else
119 year += CMOS_YEARS_OFFS;
120
121 now->tv_sec = mktime64(year, mon, day, hour, min, sec);
122 now->tv_nsec = 0;
123}
124
125/* Routines for accessing the CMOS RAM/RTC. */
126unsigned char rtc_cmos_read(unsigned char addr)
127{
128 unsigned char val;
129
130 lock_cmos_prefix(addr);
131 outb(addr, RTC_PORT(0));
132 val = inb(RTC_PORT(1));
133 lock_cmos_suffix(addr);
134
135 return val;
136}
137EXPORT_SYMBOL(rtc_cmos_read);
138
139void rtc_cmos_write(unsigned char val, unsigned char addr)
140{
141 lock_cmos_prefix(addr);
142 outb(addr, RTC_PORT(0));
143 outb(val, RTC_PORT(1));
144 lock_cmos_suffix(addr);
145}
146EXPORT_SYMBOL(rtc_cmos_write);
147
148int update_persistent_clock64(struct timespec64 now)
149{
150 return x86_platform.set_wallclock(&now);
151}
152
153/* not static: needed by APM */
154void read_persistent_clock64(struct timespec64 *ts)
155{
156 x86_platform.get_wallclock(ts);
157}
158
159
160static struct resource rtc_resources[] = {
161 [0] = {
162 .start = RTC_PORT(0),
163 .end = RTC_PORT(1),
164 .flags = IORESOURCE_IO,
165 },
166 [1] = {
167 .start = RTC_IRQ,
168 .end = RTC_IRQ,
169 .flags = IORESOURCE_IRQ,
170 }
171};
172
173static struct platform_device rtc_device = {
174 .name = "rtc_cmos",
175 .id = -1,
176 .resource = rtc_resources,
177 .num_resources = ARRAY_SIZE(rtc_resources),
178};
179
180static __init int add_rtc_cmos(void)
181{
182#ifdef CONFIG_PNP
183 static const char * const ids[] __initconst =
184 { "PNP0b00", "PNP0b01", "PNP0b02", };
185 struct pnp_dev *dev;
186 struct pnp_id *id;
187 int i;
188
189 pnp_for_each_dev(dev) {
190 for (id = dev->id; id; id = id->next) {
191 for (i = 0; i < ARRAY_SIZE(ids); i++) {
192 if (compare_pnp_id(id, ids[i]) != 0)
193 return 0;
194 }
195 }
196 }
197#endif
198 if (!x86_platform.legacy.rtc)
199 return -ENODEV;
200
201 platform_device_register(&rtc_device);
202 dev_info(&rtc_device.dev,
203 "registered platform RTC device (no PNP device found)\n");
204
205 return 0;
206}
207device_initcall(add_rtc_cmos);
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 */
23volatile unsigned long cmos_lock;
24EXPORT_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
30DEFINE_SPINLOCK(rtc_lock);
31EXPORT_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 */
43int 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
106unsigned 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. */
160unsigned 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}
171EXPORT_SYMBOL(rtc_cmos_read);
172
173void 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}
180EXPORT_SYMBOL(rtc_cmos_write);
181
182int update_persistent_clock(struct timespec now)
183{
184 return x86_platform.set_wallclock(now.tv_sec);
185}
186
187/* not static: needed by APM */
188void 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
198unsigned long long native_read_tsc(void)
199{
200 return __native_read_tsc();
201}
202EXPORT_SYMBOL(native_read_tsc);
203
204
205static 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
218static 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
225static __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}
256device_initcall(add_rtc_cmos);