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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Generic RTC interface.
4 * This version contains the part of the user interface to the Real Time Clock
5 * service. It is used with both the legacy mc146818 and also EFI
6 * Struct rtc_time and first 12 ioctl by Paul Gortmaker, 1996 - separated out
7 * from <linux/mc146818rtc.h> to this file for 2.4 kernels.
8 *
9 * Copyright (C) 1999 Hewlett-Packard Co.
10 * Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
11 */
12#ifndef _LINUX_RTC_H_
13#define _LINUX_RTC_H_
14
15
16#include <linux/types.h>
17#include <linux/interrupt.h>
18#include <linux/nvmem-provider.h>
19#include <uapi/linux/rtc.h>
20
21extern int rtc_month_days(unsigned int month, unsigned int year);
22extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
23extern int rtc_valid_tm(struct rtc_time *tm);
24extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
25extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
26ktime_t rtc_tm_to_ktime(struct rtc_time tm);
27struct rtc_time rtc_ktime_to_tm(ktime_t kt);
28
29/*
30 * rtc_tm_sub - Return the difference in seconds.
31 */
32static inline time64_t rtc_tm_sub(struct rtc_time *lhs, struct rtc_time *rhs)
33{
34 return rtc_tm_to_time64(lhs) - rtc_tm_to_time64(rhs);
35}
36
37#include <linux/device.h>
38#include <linux/seq_file.h>
39#include <linux/cdev.h>
40#include <linux/poll.h>
41#include <linux/mutex.h>
42#include <linux/timerqueue.h>
43#include <linux/workqueue.h>
44
45extern struct class *rtc_class;
46
47/*
48 * For these RTC methods the device parameter is the physical device
49 * on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
50 * was passed to rtc_device_register(). Its driver_data normally holds
51 * device state, including the rtc_device pointer for the RTC.
52 *
53 * Most of these methods are called with rtc_device.ops_lock held,
54 * through the rtc_*(struct rtc_device *, ...) calls.
55 *
56 * The (current) exceptions are mostly filesystem hooks:
57 * - the proc() hook for procfs
58 * - non-ioctl() chardev hooks: open(), release()
59 *
60 * REVISIT those periodic irq calls *do* have ops_lock when they're
61 * issued through ioctl() ...
62 */
63struct rtc_class_ops {
64 int (*ioctl)(struct device *, unsigned int, unsigned long);
65 int (*read_time)(struct device *, struct rtc_time *);
66 int (*set_time)(struct device *, struct rtc_time *);
67 int (*read_alarm)(struct device *, struct rtc_wkalrm *);
68 int (*set_alarm)(struct device *, struct rtc_wkalrm *);
69 int (*proc)(struct device *, struct seq_file *);
70 int (*alarm_irq_enable)(struct device *, unsigned int enabled);
71 int (*read_offset)(struct device *, long *offset);
72 int (*set_offset)(struct device *, long offset);
73};
74
75struct rtc_device;
76
77struct rtc_timer {
78 struct timerqueue_node node;
79 ktime_t period;
80 void (*func)(struct rtc_device *rtc);
81 struct rtc_device *rtc;
82 int enabled;
83};
84
85/* flags */
86#define RTC_DEV_BUSY 0
87
88struct rtc_device {
89 struct device dev;
90 struct module *owner;
91
92 int id;
93
94 const struct rtc_class_ops *ops;
95 struct mutex ops_lock;
96
97 struct cdev char_dev;
98 unsigned long flags;
99
100 unsigned long irq_data;
101 spinlock_t irq_lock;
102 wait_queue_head_t irq_queue;
103 struct fasync_struct *async_queue;
104
105 int irq_freq;
106 int max_user_freq;
107
108 struct timerqueue_head timerqueue;
109 struct rtc_timer aie_timer;
110 struct rtc_timer uie_rtctimer;
111 struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
112 int pie_enabled;
113 struct work_struct irqwork;
114 /* Some hardware can't support UIE mode */
115 int uie_unsupported;
116
117 /* Number of nsec it takes to set the RTC clock. This influences when
118 * the set ops are called. An offset:
119 * - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
120 * - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
121 * - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
122 */
123 long set_offset_nsec;
124
125 bool registered;
126
127 /* Old ABI support */
128 bool nvram_old_abi;
129 struct bin_attribute *nvram;
130
131 time64_t range_min;
132 timeu64_t range_max;
133 time64_t start_secs;
134 time64_t offset_secs;
135 bool set_start_time;
136
137#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
138 struct work_struct uie_task;
139 struct timer_list uie_timer;
140 /* Those fields are protected by rtc->irq_lock */
141 unsigned int oldsecs;
142 unsigned int uie_irq_active:1;
143 unsigned int stop_uie_polling:1;
144 unsigned int uie_task_active:1;
145 unsigned int uie_timer_active:1;
146#endif
147};
148#define to_rtc_device(d) container_of(d, struct rtc_device, dev)
149
150#define rtc_lock(d) mutex_lock(&d->ops_lock)
151#define rtc_unlock(d) mutex_unlock(&d->ops_lock)
152
153/* useful timestamps */
154#define RTC_TIMESTAMP_BEGIN_0000 -62167219200ULL /* 0000-01-01 00:00:00 */
155#define RTC_TIMESTAMP_BEGIN_1900 -2208988800LL /* 1900-01-01 00:00:00 */
156#define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
157#define RTC_TIMESTAMP_END_2063 2966371199LL /* 2063-12-31 23:59:59 */
158#define RTC_TIMESTAMP_END_2079 3471292799LL /* 2079-12-31 23:59:59 */
159#define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
160#define RTC_TIMESTAMP_END_2199 7258118399LL /* 2199-12-31 23:59:59 */
161#define RTC_TIMESTAMP_END_9999 253402300799LL /* 9999-12-31 23:59:59 */
162
163extern struct rtc_device *devm_rtc_device_register(struct device *dev,
164 const char *name,
165 const struct rtc_class_ops *ops,
166 struct module *owner);
167struct rtc_device *devm_rtc_allocate_device(struct device *dev);
168int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
169
170extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
171extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
172extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
173int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
174extern int rtc_read_alarm(struct rtc_device *rtc,
175 struct rtc_wkalrm *alrm);
176extern int rtc_set_alarm(struct rtc_device *rtc,
177 struct rtc_wkalrm *alrm);
178extern int rtc_initialize_alarm(struct rtc_device *rtc,
179 struct rtc_wkalrm *alrm);
180extern void rtc_update_irq(struct rtc_device *rtc,
181 unsigned long num, unsigned long events);
182
183extern struct rtc_device *rtc_class_open(const char *name);
184extern void rtc_class_close(struct rtc_device *rtc);
185
186extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
187extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
188extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
189extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
190extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
191 unsigned int enabled);
192
193void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
194void rtc_aie_update_irq(struct rtc_device *rtc);
195void rtc_uie_update_irq(struct rtc_device *rtc);
196enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
197
198void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
199 struct rtc_device *rtc);
200int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
201 ktime_t expires, ktime_t period);
202void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
203int rtc_read_offset(struct rtc_device *rtc, long *offset);
204int rtc_set_offset(struct rtc_device *rtc, long offset);
205void rtc_timer_do_work(struct work_struct *work);
206
207static inline bool is_leap_year(unsigned int year)
208{
209 return (!(year % 4) && (year % 100)) || !(year % 400);
210}
211
212/* Determine if we can call to driver to set the time. Drivers can only be
213 * called to set a second aligned time value, and the field set_offset_nsec
214 * specifies how far away from the second aligned time to call the driver.
215 *
216 * This also computes 'to_set' which is the time we are trying to set, and has
217 * a zero in tv_nsecs, such that:
218 * to_set - set_delay_nsec == now +/- FUZZ
219 *
220 */
221static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
222 struct timespec64 *to_set,
223 const struct timespec64 *now)
224{
225 /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
226 const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
227 struct timespec64 delay = {.tv_sec = 0,
228 .tv_nsec = set_offset_nsec};
229
230 *to_set = timespec64_add(*now, delay);
231
232 if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
233 to_set->tv_nsec = 0;
234 return true;
235 }
236
237 if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
238 to_set->tv_sec++;
239 to_set->tv_nsec = 0;
240 return true;
241 }
242 return false;
243}
244
245#define rtc_register_device(device) \
246 __rtc_register_device(THIS_MODULE, device)
247
248#ifdef CONFIG_RTC_HCTOSYS_DEVICE
249extern int rtc_hctosys_ret;
250#else
251#define rtc_hctosys_ret -ENODEV
252#endif
253
254#ifdef CONFIG_RTC_NVMEM
255int rtc_nvmem_register(struct rtc_device *rtc,
256 struct nvmem_config *nvmem_config);
257void rtc_nvmem_unregister(struct rtc_device *rtc);
258#else
259static inline int rtc_nvmem_register(struct rtc_device *rtc,
260 struct nvmem_config *nvmem_config)
261{
262 return 0;
263}
264static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
265#endif
266
267#ifdef CONFIG_RTC_INTF_SYSFS
268int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
269int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
270#else
271static inline
272int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
273{
274 return 0;
275}
276
277static inline
278int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
279{
280 return 0;
281}
282#endif
283#endif /* _LINUX_RTC_H_ */