1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
// SPDX-License-Identifier: GPL-2.0
/*
* RTC related functions
*/
#include <linux/platform_device.h>
#include <linux/mc146818rtc.h>
#include <linux/export.h>
#include <linux/pnp.h>
#include <asm/vsyscall.h>
#include <asm/x86_init.h>
#include <asm/time.h>
#include <asm/intel-mid.h>
#include <asm/setup.h>
#ifdef CONFIG_X86_32
/*
* This is a special lock that is owned by the CPU and holds the index
* register we are working with. It is required for NMI access to the
* CMOS/RTC registers. See arch/x86/include/asm/mc146818rtc.h for details.
*/
volatile unsigned long cmos_lock;
EXPORT_SYMBOL(cmos_lock);
#endif /* CONFIG_X86_32 */
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
/*
* In order to set the CMOS clock precisely, mach_set_cmos_time has to be
* called 500 ms after the second nowtime has started, because when
* nowtime is written into the registers of the CMOS clock, it will
* jump to the next second precisely 500 ms later. Check the Motorola
* MC146818A or Dallas DS12887 data sheet for details.
*/
int mach_set_cmos_time(const struct timespec64 *now)
{
unsigned long long nowtime = now->tv_sec;
struct rtc_time tm;
int retval = 0;
rtc_time64_to_tm(nowtime, &tm);
if (!rtc_valid_tm(&tm)) {
retval = mc146818_set_time(&tm);
if (retval)
printk(KERN_ERR "%s: RTC write failed with error %d\n",
__func__, retval);
} else {
printk(KERN_ERR
"%s: Invalid RTC value: write of %llx to RTC failed\n",
__func__, nowtime);
retval = -EINVAL;
}
return retval;
}
void mach_get_cmos_time(struct timespec64 *now)
{
struct rtc_time tm;
/*
* If pm_trace abused the RTC as storage, set the timespec to 0,
* which tells the caller that this RTC value is unusable.
*/
if (!pm_trace_rtc_valid()) {
now->tv_sec = now->tv_nsec = 0;
return;
}
if (mc146818_get_time(&tm, 1000)) {
pr_err("Unable to read current time from RTC\n");
now->tv_sec = now->tv_nsec = 0;
return;
}
now->tv_sec = rtc_tm_to_time64(&tm);
now->tv_nsec = 0;
}
/* Routines for accessing the CMOS RAM/RTC. */
unsigned char rtc_cmos_read(unsigned char addr)
{
unsigned char val;
lock_cmos_prefix(addr);
outb(addr, RTC_PORT(0));
val = inb(RTC_PORT(1));
lock_cmos_suffix(addr);
return val;
}
EXPORT_SYMBOL(rtc_cmos_read);
void rtc_cmos_write(unsigned char val, unsigned char addr)
{
lock_cmos_prefix(addr);
outb(addr, RTC_PORT(0));
outb(val, RTC_PORT(1));
lock_cmos_suffix(addr);
}
EXPORT_SYMBOL(rtc_cmos_write);
int update_persistent_clock64(struct timespec64 now)
{
return x86_platform.set_wallclock(&now);
}
/* not static: needed by APM */
void read_persistent_clock64(struct timespec64 *ts)
{
x86_platform.get_wallclock(ts);
}
static struct resource rtc_resources[] = {
[0] = {
.start = RTC_PORT(0),
.end = RTC_PORT(1),
.flags = IORESOURCE_IO,
},
[1] = {
.start = RTC_IRQ,
.end = RTC_IRQ,
.flags = IORESOURCE_IRQ,
}
};
static struct platform_device rtc_device = {
.name = "rtc_cmos",
.id = -1,
.resource = rtc_resources,
.num_resources = ARRAY_SIZE(rtc_resources),
};
static __init int add_rtc_cmos(void)
{
#ifdef CONFIG_PNP
static const char * const ids[] __initconst =
{ "PNP0b00", "PNP0b01", "PNP0b02", };
struct pnp_dev *dev;
int i;
pnp_for_each_dev(dev) {
for (i = 0; i < ARRAY_SIZE(ids); i++) {
if (compare_pnp_id(dev->id, ids[i]) != 0)
return 0;
}
}
#endif
if (!x86_platform.legacy.rtc)
return -ENODEV;
platform_device_register(&rtc_device);
dev_info(&rtc_device.dev,
"registered platform RTC device (no PNP device found)\n");
return 0;
}
device_initcall(add_rtc_cmos);
|
