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			       __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	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 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);
210