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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
37static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
38{
39 rtc_time64_to_tm(time, tm);
40}
41
42static inline int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
43{
44 *time = rtc_tm_to_time64(tm);
45
46 return 0;
47}
48
49#include <linux/device.h>
50#include <linux/seq_file.h>
51#include <linux/cdev.h>
52#include <linux/poll.h>
53#include <linux/mutex.h>
54#include <linux/timerqueue.h>
55#include <linux/workqueue.h>
56
57extern struct class *rtc_class;
58
59/*
60 * For these RTC methods the device parameter is the physical device
61 * on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
62 * was passed to rtc_device_register(). Its driver_data normally holds
63 * device state, including the rtc_device pointer for the RTC.
64 *
65 * Most of these methods are called with rtc_device.ops_lock held,
66 * through the rtc_*(struct rtc_device *, ...) calls.
67 *
68 * The (current) exceptions are mostly filesystem hooks:
69 * - the proc() hook for procfs
70 * - non-ioctl() chardev hooks: open(), release(), read_callback()
71 *
72 * REVISIT those periodic irq calls *do* have ops_lock when they're
73 * issued through ioctl() ...
74 */
75struct rtc_class_ops {
76 int (*ioctl)(struct device *, unsigned int, unsigned long);
77 int (*read_time)(struct device *, struct rtc_time *);
78 int (*set_time)(struct device *, struct rtc_time *);
79 int (*read_alarm)(struct device *, struct rtc_wkalrm *);
80 int (*set_alarm)(struct device *, struct rtc_wkalrm *);
81 int (*proc)(struct device *, struct seq_file *);
82 int (*set_mmss64)(struct device *, time64_t secs);
83 int (*set_mmss)(struct device *, unsigned long secs);
84 int (*read_callback)(struct device *, int data);
85 int (*alarm_irq_enable)(struct device *, unsigned int enabled);
86 int (*read_offset)(struct device *, long *offset);
87 int (*set_offset)(struct device *, long offset);
88};
89
90#define RTC_DEVICE_NAME_SIZE 20
91typedef struct rtc_task {
92 void (*func)(void *private_data);
93 void *private_data;
94} rtc_task_t;
95
96
97struct rtc_timer {
98 struct rtc_task task;
99 struct timerqueue_node node;
100 ktime_t period;
101 int enabled;
102};
103
104
105/* flags */
106#define RTC_DEV_BUSY 0
107
108struct rtc_device {
109 struct device dev;
110 struct module *owner;
111
112 int id;
113
114 const struct rtc_class_ops *ops;
115 struct mutex ops_lock;
116
117 struct cdev char_dev;
118 unsigned long flags;
119
120 unsigned long irq_data;
121 spinlock_t irq_lock;
122 wait_queue_head_t irq_queue;
123 struct fasync_struct *async_queue;
124
125 struct rtc_task *irq_task;
126 spinlock_t irq_task_lock;
127 int irq_freq;
128 int max_user_freq;
129
130 struct timerqueue_head timerqueue;
131 struct rtc_timer aie_timer;
132 struct rtc_timer uie_rtctimer;
133 struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
134 int pie_enabled;
135 struct work_struct irqwork;
136 /* Some hardware can't support UIE mode */
137 int uie_unsupported;
138
139 /* Number of nsec it takes to set the RTC clock. This influences when
140 * the set ops are called. An offset:
141 * - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
142 * - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
143 * - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
144 */
145 long set_offset_nsec;
146
147 bool registered;
148
149 struct nvmem_config *nvmem_config;
150 struct nvmem_device *nvmem;
151 /* Old ABI support */
152 bool nvram_old_abi;
153 struct bin_attribute *nvram;
154
155#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
156 struct work_struct uie_task;
157 struct timer_list uie_timer;
158 /* Those fields are protected by rtc->irq_lock */
159 unsigned int oldsecs;
160 unsigned int uie_irq_active:1;
161 unsigned int stop_uie_polling:1;
162 unsigned int uie_task_active:1;
163 unsigned int uie_timer_active:1;
164#endif
165};
166#define to_rtc_device(d) container_of(d, struct rtc_device, dev)
167
168extern struct rtc_device *rtc_device_register(const char *name,
169 struct device *dev,
170 const struct rtc_class_ops *ops,
171 struct module *owner);
172extern struct rtc_device *devm_rtc_device_register(struct device *dev,
173 const char *name,
174 const struct rtc_class_ops *ops,
175 struct module *owner);
176struct rtc_device *devm_rtc_allocate_device(struct device *dev);
177int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
178extern void rtc_device_unregister(struct rtc_device *rtc);
179extern void devm_rtc_device_unregister(struct device *dev,
180 struct rtc_device *rtc);
181
182extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
183extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
184extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
185int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
186extern int rtc_read_alarm(struct rtc_device *rtc,
187 struct rtc_wkalrm *alrm);
188extern int rtc_set_alarm(struct rtc_device *rtc,
189 struct rtc_wkalrm *alrm);
190extern int rtc_initialize_alarm(struct rtc_device *rtc,
191 struct rtc_wkalrm *alrm);
192extern void rtc_update_irq(struct rtc_device *rtc,
193 unsigned long num, unsigned long events);
194
195extern struct rtc_device *rtc_class_open(const char *name);
196extern void rtc_class_close(struct rtc_device *rtc);
197
198extern int rtc_irq_register(struct rtc_device *rtc,
199 struct rtc_task *task);
200extern void rtc_irq_unregister(struct rtc_device *rtc,
201 struct rtc_task *task);
202extern int rtc_irq_set_state(struct rtc_device *rtc,
203 struct rtc_task *task, int enabled);
204extern int rtc_irq_set_freq(struct rtc_device *rtc,
205 struct rtc_task *task, int freq);
206extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
207extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
208extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
209 unsigned int enabled);
210
211void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
212void rtc_aie_update_irq(void *private);
213void rtc_uie_update_irq(void *private);
214enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
215
216int rtc_register(rtc_task_t *task);
217int rtc_unregister(rtc_task_t *task);
218int rtc_control(rtc_task_t *t, unsigned int cmd, unsigned long arg);
219
220void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data);
221int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
222 ktime_t expires, ktime_t period);
223void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
224int rtc_read_offset(struct rtc_device *rtc, long *offset);
225int rtc_set_offset(struct rtc_device *rtc, long offset);
226void rtc_timer_do_work(struct work_struct *work);
227
228static inline bool is_leap_year(unsigned int year)
229{
230 return (!(year % 4) && (year % 100)) || !(year % 400);
231}
232
233/* Determine if we can call to driver to set the time. Drivers can only be
234 * called to set a second aligned time value, and the field set_offset_nsec
235 * specifies how far away from the second aligned time to call the driver.
236 *
237 * This also computes 'to_set' which is the time we are trying to set, and has
238 * a zero in tv_nsecs, such that:
239 * to_set - set_delay_nsec == now +/- FUZZ
240 *
241 */
242static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
243 struct timespec64 *to_set,
244 const struct timespec64 *now)
245{
246 /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
247 const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
248 struct timespec64 delay = {.tv_sec = 0,
249 .tv_nsec = set_offset_nsec};
250
251 *to_set = timespec64_add(*now, delay);
252
253 if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
254 to_set->tv_nsec = 0;
255 return true;
256 }
257
258 if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
259 to_set->tv_sec++;
260 to_set->tv_nsec = 0;
261 return true;
262 }
263 return false;
264}
265
266#define rtc_register_device(device) \
267 __rtc_register_device(THIS_MODULE, device)
268
269#ifdef CONFIG_RTC_HCTOSYS_DEVICE
270extern int rtc_hctosys_ret;
271#else
272#define rtc_hctosys_ret -ENODEV
273#endif
274
275#endif /* _LINUX_RTC_H_ */