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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/export.h>
8#include <linux/pnp.h>
9
10#include <asm/vsyscall.h>
11#include <asm/x86_init.h>
12#include <asm/time.h>
13#include <asm/intel-mid.h>
14#include <asm/setup.h>
15
16#ifdef CONFIG_X86_32
17/*
18 * This is a special lock that is owned by the CPU and holds the index
19 * register we are working with. It is required for NMI access to the
20 * CMOS/RTC registers. See arch/x86/include/asm/mc146818rtc.h for details.
21 */
22volatile unsigned long cmos_lock;
23EXPORT_SYMBOL(cmos_lock);
24#endif /* CONFIG_X86_32 */
25
26DEFINE_SPINLOCK(rtc_lock);
27EXPORT_SYMBOL(rtc_lock);
28
29/*
30 * In order to set the CMOS clock precisely, mach_set_cmos_time 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 */
36int mach_set_cmos_time(const struct timespec64 *now)
37{
38 unsigned long long nowtime = now->tv_sec;
39 struct rtc_time tm;
40 int retval = 0;
41
42 rtc_time64_to_tm(nowtime, &tm);
43 if (!rtc_valid_tm(&tm)) {
44 retval = mc146818_set_time(&tm);
45 if (retval)
46 printk(KERN_ERR "%s: RTC write failed with error %d\n",
47 __func__, retval);
48 } else {
49 printk(KERN_ERR
50 "%s: Invalid RTC value: write of %llx to RTC failed\n",
51 __func__, nowtime);
52 retval = -EINVAL;
53 }
54 return retval;
55}
56
57void mach_get_cmos_time(struct timespec64 *now)
58{
59 struct rtc_time tm;
60
61 /*
62 * If pm_trace abused the RTC as storage, set the timespec to 0,
63 * which tells the caller that this RTC value is unusable.
64 */
65 if (!pm_trace_rtc_valid()) {
66 now->tv_sec = now->tv_nsec = 0;
67 return;
68 }
69
70 if (mc146818_get_time(&tm, 1000)) {
71 pr_err("Unable to read current time from RTC\n");
72 now->tv_sec = now->tv_nsec = 0;
73 return;
74 }
75
76 now->tv_sec = rtc_tm_to_time64(&tm);
77 now->tv_nsec = 0;
78}
79
80/* Routines for accessing the CMOS RAM/RTC. */
81unsigned char rtc_cmos_read(unsigned char addr)
82{
83 unsigned char val;
84
85 lock_cmos_prefix(addr);
86 outb(addr, RTC_PORT(0));
87 val = inb(RTC_PORT(1));
88 lock_cmos_suffix(addr);
89
90 return val;
91}
92EXPORT_SYMBOL(rtc_cmos_read);
93
94void rtc_cmos_write(unsigned char val, unsigned char addr)
95{
96 lock_cmos_prefix(addr);
97 outb(addr, RTC_PORT(0));
98 outb(val, RTC_PORT(1));
99 lock_cmos_suffix(addr);
100}
101EXPORT_SYMBOL(rtc_cmos_write);
102
103int update_persistent_clock64(struct timespec64 now)
104{
105 return x86_platform.set_wallclock(&now);
106}
107
108/* not static: needed by APM */
109void read_persistent_clock64(struct timespec64 *ts)
110{
111 x86_platform.get_wallclock(ts);
112}
113
114
115static struct resource rtc_resources[] = {
116 [0] = {
117 .start = RTC_PORT(0),
118 .end = RTC_PORT(1),
119 .flags = IORESOURCE_IO,
120 },
121 [1] = {
122 .start = RTC_IRQ,
123 .end = RTC_IRQ,
124 .flags = IORESOURCE_IRQ,
125 }
126};
127
128static struct platform_device rtc_device = {
129 .name = "rtc_cmos",
130 .id = -1,
131 .resource = rtc_resources,
132 .num_resources = ARRAY_SIZE(rtc_resources),
133};
134
135static __init int add_rtc_cmos(void)
136{
137#ifdef CONFIG_PNP
138 static const char * const ids[] __initconst =
139 { "PNP0b00", "PNP0b01", "PNP0b02", };
140 struct pnp_dev *dev;
141 int i;
142
143 pnp_for_each_dev(dev) {
144 for (i = 0; i < ARRAY_SIZE(ids); i++) {
145 if (compare_pnp_id(dev->id, ids[i]) != 0)
146 return 0;
147 }
148 }
149#endif
150 if (!x86_platform.legacy.rtc)
151 return -ENODEV;
152
153 platform_device_register(&rtc_device);
154 dev_info(&rtc_device.dev,
155 "registered platform RTC device (no PNP device found)\n");
156
157 return 0;
158}
159device_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/intel-mid.h>
16#include <asm/setup.h>
17
18#ifdef CONFIG_X86_32
19/*
20 * This is a special lock that is owned by the CPU and holds the index
21 * register we are working with. It is required for NMI access to the
22 * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
23 */
24volatile unsigned long cmos_lock;
25EXPORT_SYMBOL(cmos_lock);
26#endif /* CONFIG_X86_32 */
27
28/* For two digit years assume time is always after that */
29#define CMOS_YEARS_OFFS 2000
30
31DEFINE_SPINLOCK(rtc_lock);
32EXPORT_SYMBOL(rtc_lock);
33
34/*
35 * In order to set the CMOS clock precisely, set_rtc_mmss has to be
36 * called 500 ms after the second nowtime has started, because when
37 * nowtime is written into the registers of the CMOS clock, it will
38 * jump to the next second precisely 500 ms later. Check the Motorola
39 * MC146818A or Dallas DS12887 data sheet for details.
40 */
41int mach_set_rtc_mmss(const struct timespec *now)
42{
43 unsigned long nowtime = now->tv_sec;
44 struct rtc_time tm;
45 int retval = 0;
46
47 rtc_time_to_tm(nowtime, &tm);
48 if (!rtc_valid_tm(&tm)) {
49 retval = mc146818_set_time(&tm);
50 if (retval)
51 printk(KERN_ERR "%s: RTC write failed with error %d\n",
52 __func__, retval);
53 } else {
54 printk(KERN_ERR
55 "%s: Invalid RTC value: write of %lx to RTC failed\n",
56 __func__, nowtime);
57 retval = -EINVAL;
58 }
59 return retval;
60}
61
62void mach_get_cmos_time(struct timespec *now)
63{
64 unsigned int status, year, mon, day, hour, min, sec, century = 0;
65 unsigned long flags;
66
67 /*
68 * If pm_trace abused the RTC as storage, set the timespec to 0,
69 * which tells the caller that this RTC value is unusable.
70 */
71 if (!pm_trace_rtc_valid()) {
72 now->tv_sec = now->tv_nsec = 0;
73 return;
74 }
75
76 spin_lock_irqsave(&rtc_lock, flags);
77
78 /*
79 * If UIP is clear, then we have >= 244 microseconds before
80 * RTC registers will be updated. Spec sheet says that this
81 * is the reliable way to read RTC - registers. If UIP is set
82 * then the register access might be invalid.
83 */
84 while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
85 cpu_relax();
86
87 sec = CMOS_READ(RTC_SECONDS);
88 min = CMOS_READ(RTC_MINUTES);
89 hour = CMOS_READ(RTC_HOURS);
90 day = CMOS_READ(RTC_DAY_OF_MONTH);
91 mon = CMOS_READ(RTC_MONTH);
92 year = CMOS_READ(RTC_YEAR);
93
94#ifdef CONFIG_ACPI
95 if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
96 acpi_gbl_FADT.century)
97 century = CMOS_READ(acpi_gbl_FADT.century);
98#endif
99
100 status = CMOS_READ(RTC_CONTROL);
101 WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY));
102
103 spin_unlock_irqrestore(&rtc_lock, flags);
104
105 if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) {
106 sec = bcd2bin(sec);
107 min = bcd2bin(min);
108 hour = bcd2bin(hour);
109 day = bcd2bin(day);
110 mon = bcd2bin(mon);
111 year = bcd2bin(year);
112 }
113
114 if (century) {
115 century = bcd2bin(century);
116 year += century * 100;
117 } else
118 year += CMOS_YEARS_OFFS;
119
120 now->tv_sec = mktime(year, mon, day, hour, min, sec);
121 now->tv_nsec = 0;
122}
123
124/* Routines for accessing the CMOS RAM/RTC. */
125unsigned char rtc_cmos_read(unsigned char addr)
126{
127 unsigned char val;
128
129 lock_cmos_prefix(addr);
130 outb(addr, RTC_PORT(0));
131 val = inb(RTC_PORT(1));
132 lock_cmos_suffix(addr);
133
134 return val;
135}
136EXPORT_SYMBOL(rtc_cmos_read);
137
138void rtc_cmos_write(unsigned char val, unsigned char addr)
139{
140 lock_cmos_prefix(addr);
141 outb(addr, RTC_PORT(0));
142 outb(val, RTC_PORT(1));
143 lock_cmos_suffix(addr);
144}
145EXPORT_SYMBOL(rtc_cmos_write);
146
147int update_persistent_clock(struct timespec now)
148{
149 return x86_platform.set_wallclock(&now);
150}
151
152/* not static: needed by APM */
153void read_persistent_clock(struct timespec *ts)
154{
155 x86_platform.get_wallclock(ts);
156}
157
158
159static struct resource rtc_resources[] = {
160 [0] = {
161 .start = RTC_PORT(0),
162 .end = RTC_PORT(1),
163 .flags = IORESOURCE_IO,
164 },
165 [1] = {
166 .start = RTC_IRQ,
167 .end = RTC_IRQ,
168 .flags = IORESOURCE_IRQ,
169 }
170};
171
172static struct platform_device rtc_device = {
173 .name = "rtc_cmos",
174 .id = -1,
175 .resource = rtc_resources,
176 .num_resources = ARRAY_SIZE(rtc_resources),
177};
178
179static __init int add_rtc_cmos(void)
180{
181#ifdef CONFIG_PNP
182 static const char * const ids[] __initconst =
183 { "PNP0b00", "PNP0b01", "PNP0b02", };
184 struct pnp_dev *dev;
185 struct pnp_id *id;
186 int i;
187
188 pnp_for_each_dev(dev) {
189 for (id = dev->id; id; id = id->next) {
190 for (i = 0; i < ARRAY_SIZE(ids); i++) {
191 if (compare_pnp_id(id, ids[i]) != 0)
192 return 0;
193 }
194 }
195 }
196#endif
197 if (!x86_platform.legacy.rtc)
198 return -ENODEV;
199
200 platform_device_register(&rtc_device);
201 dev_info(&rtc_device.dev,
202 "registered platform RTC device (no PNP device found)\n");
203
204 return 0;
205}
206device_initcall(add_rtc_cmos);