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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)) {
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 struct pnp_id *id;
142 int i;
143
144 pnp_for_each_dev(dev) {
145 for (id = dev->id; id; id = id->next) {
146 for (i = 0; i < ARRAY_SIZE(ids); i++) {
147 if (compare_pnp_id(id, ids[i]) != 0)
148 return 0;
149 }
150 }
151 }
152#endif
153 if (!x86_platform.legacy.rtc)
154 return -ENODEV;
155
156 platform_device_register(&rtc_device);
157 dev_info(&rtc_device.dev,
158 "registered platform RTC device (no PNP device found)\n");
159
160 return 0;
161}
162device_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/rtc.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 = set_rtc_time(&tm);
50 if (retval)
51 printk(KERN_ERR "%s: RTC write failed with error %d\n",
52 __FUNCTION__, retval);
53 } else {
54 printk(KERN_ERR
55 "%s: Invalid RTC value: write of %lx to RTC failed\n",
56 __FUNCTION__, 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 spin_lock_irqsave(&rtc_lock, flags);
68
69 /*
70 * If UIP is clear, then we have >= 244 microseconds before
71 * RTC registers will be updated. Spec sheet says that this
72 * is the reliable way to read RTC - registers. If UIP is set
73 * then the register access might be invalid.
74 */
75 while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
76 cpu_relax();
77
78 sec = CMOS_READ(RTC_SECONDS);
79 min = CMOS_READ(RTC_MINUTES);
80 hour = CMOS_READ(RTC_HOURS);
81 day = CMOS_READ(RTC_DAY_OF_MONTH);
82 mon = CMOS_READ(RTC_MONTH);
83 year = CMOS_READ(RTC_YEAR);
84
85#ifdef CONFIG_ACPI
86 if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
87 acpi_gbl_FADT.century)
88 century = CMOS_READ(acpi_gbl_FADT.century);
89#endif
90
91 status = CMOS_READ(RTC_CONTROL);
92 WARN_ON_ONCE(RTC_ALWAYS_BCD && (status & RTC_DM_BINARY));
93
94 spin_unlock_irqrestore(&rtc_lock, flags);
95
96 if (RTC_ALWAYS_BCD || !(status & RTC_DM_BINARY)) {
97 sec = bcd2bin(sec);
98 min = bcd2bin(min);
99 hour = bcd2bin(hour);
100 day = bcd2bin(day);
101 mon = bcd2bin(mon);
102 year = bcd2bin(year);
103 }
104
105 if (century) {
106 century = bcd2bin(century);
107 year += century * 100;
108 } else
109 year += CMOS_YEARS_OFFS;
110
111 now->tv_sec = mktime(year, mon, day, hour, min, sec);
112 now->tv_nsec = 0;
113}
114
115/* Routines for accessing the CMOS RAM/RTC. */
116unsigned char rtc_cmos_read(unsigned char addr)
117{
118 unsigned char val;
119
120 lock_cmos_prefix(addr);
121 outb(addr, RTC_PORT(0));
122 val = inb(RTC_PORT(1));
123 lock_cmos_suffix(addr);
124
125 return val;
126}
127EXPORT_SYMBOL(rtc_cmos_read);
128
129void rtc_cmos_write(unsigned char val, unsigned char addr)
130{
131 lock_cmos_prefix(addr);
132 outb(addr, RTC_PORT(0));
133 outb(val, RTC_PORT(1));
134 lock_cmos_suffix(addr);
135}
136EXPORT_SYMBOL(rtc_cmos_write);
137
138int update_persistent_clock(struct timespec now)
139{
140 return x86_platform.set_wallclock(&now);
141}
142
143/* not static: needed by APM */
144void read_persistent_clock(struct timespec *ts)
145{
146 x86_platform.get_wallclock(ts);
147}
148
149
150static struct resource rtc_resources[] = {
151 [0] = {
152 .start = RTC_PORT(0),
153 .end = RTC_PORT(1),
154 .flags = IORESOURCE_IO,
155 },
156 [1] = {
157 .start = RTC_IRQ,
158 .end = RTC_IRQ,
159 .flags = IORESOURCE_IRQ,
160 }
161};
162
163static struct platform_device rtc_device = {
164 .name = "rtc_cmos",
165 .id = -1,
166 .resource = rtc_resources,
167 .num_resources = ARRAY_SIZE(rtc_resources),
168};
169
170static __init int add_rtc_cmos(void)
171{
172#ifdef CONFIG_PNP
173 static const char * const const ids[] __initconst =
174 { "PNP0b00", "PNP0b01", "PNP0b02", };
175 struct pnp_dev *dev;
176 struct pnp_id *id;
177 int i;
178
179 pnp_for_each_dev(dev) {
180 for (id = dev->id; id; id = id->next) {
181 for (i = 0; i < ARRAY_SIZE(ids); i++) {
182 if (compare_pnp_id(id, ids[i]) != 0)
183 return 0;
184 }
185 }
186 }
187#endif
188 if (of_have_populated_dt())
189 return 0;
190
191 /* Intel MID platforms don't have ioport rtc */
192 if (intel_mid_identify_cpu())
193 return -ENODEV;
194
195#ifdef CONFIG_ACPI
196 if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_CMOS_RTC) {
197 /* This warning can likely go away again in a year or two. */
198 pr_info("ACPI: not registering RTC platform device\n");
199 return -ENODEV;
200 }
201#endif
202
203 platform_device_register(&rtc_device);
204 dev_info(&rtc_device.dev,
205 "registered platform RTC device (no PNP device found)\n");
206
207 return 0;
208}
209device_initcall(add_rtc_cmos);