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
21 extern int rtc_month_days(unsigned int month, unsigned int year);
22 extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
23 extern int rtc_valid_tm(struct rtc_time *tm);
24 extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
25 extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
26 ktime_t rtc_tm_to_ktime(struct rtc_time tm);
27 struct rtc_time rtc_ktime_to_tm(ktime_t kt);
28
29 /*
30 * rtc_tm_sub - Return the difference in seconds.
31 */
rtc_tm_sub(struct rtc_time * lhs,struct rtc_time * rhs)32 static 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
rtc_time_to_tm(unsigned long time,struct rtc_time * tm)37 static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
38 {
39 rtc_time64_to_tm(time, tm);
40 }
41
rtc_tm_to_time(struct rtc_time * tm,unsigned long * time)42 static 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
57 extern 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 */
75 struct 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 struct rtc_timer {
91 struct timerqueue_node node;
92 ktime_t period;
93 void (*func)(void *private_data);
94 void *private_data;
95 int enabled;
96 };
97
98
99 /* flags */
100 #define RTC_DEV_BUSY 0
101
102 struct rtc_device {
103 struct device dev;
104 struct module *owner;
105
106 int id;
107
108 const struct rtc_class_ops *ops;
109 struct mutex ops_lock;
110
111 struct cdev char_dev;
112 unsigned long flags;
113
114 unsigned long irq_data;
115 spinlock_t irq_lock;
116 wait_queue_head_t irq_queue;
117 struct fasync_struct *async_queue;
118
119 int irq_freq;
120 int max_user_freq;
121
122 struct timerqueue_head timerqueue;
123 struct rtc_timer aie_timer;
124 struct rtc_timer uie_rtctimer;
125 struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
126 int pie_enabled;
127 struct work_struct irqwork;
128 /* Some hardware can't support UIE mode */
129 int uie_unsupported;
130
131 /* Number of nsec it takes to set the RTC clock. This influences when
132 * the set ops are called. An offset:
133 * - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
134 * - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
135 * - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
136 */
137 long set_offset_nsec;
138
139 bool registered;
140
141 struct nvmem_device *nvmem;
142 /* Old ABI support */
143 bool nvram_old_abi;
144 struct bin_attribute *nvram;
145
146 time64_t range_min;
147 timeu64_t range_max;
148 time64_t start_secs;
149 time64_t offset_secs;
150 bool set_start_time;
151
152 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
153 struct work_struct uie_task;
154 struct timer_list uie_timer;
155 /* Those fields are protected by rtc->irq_lock */
156 unsigned int oldsecs;
157 unsigned int uie_irq_active:1;
158 unsigned int stop_uie_polling:1;
159 unsigned int uie_task_active:1;
160 unsigned int uie_timer_active:1;
161 #endif
162 };
163 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
164
165 /* useful timestamps */
166 #define RTC_TIMESTAMP_BEGIN_1900 -2208988800LL /* 1900-01-01 00:00:00 */
167 #define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
168 #define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
169
170 extern struct rtc_device *rtc_device_register(const char *name,
171 struct device *dev,
172 const struct rtc_class_ops *ops,
173 struct module *owner);
174 extern struct rtc_device *devm_rtc_device_register(struct device *dev,
175 const char *name,
176 const struct rtc_class_ops *ops,
177 struct module *owner);
178 struct rtc_device *devm_rtc_allocate_device(struct device *dev);
179 int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
180 extern void rtc_device_unregister(struct rtc_device *rtc);
181 extern void devm_rtc_device_unregister(struct device *dev,
182 struct rtc_device *rtc);
183
184 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
185 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
186 extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
187 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
188 extern int rtc_read_alarm(struct rtc_device *rtc,
189 struct rtc_wkalrm *alrm);
190 extern int rtc_set_alarm(struct rtc_device *rtc,
191 struct rtc_wkalrm *alrm);
192 extern int rtc_initialize_alarm(struct rtc_device *rtc,
193 struct rtc_wkalrm *alrm);
194 extern void rtc_update_irq(struct rtc_device *rtc,
195 unsigned long num, unsigned long events);
196
197 extern struct rtc_device *rtc_class_open(const char *name);
198 extern void rtc_class_close(struct rtc_device *rtc);
199
200 extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
201 extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
202 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
203 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
204 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
205 unsigned int enabled);
206
207 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
208 void rtc_aie_update_irq(void *private);
209 void rtc_uie_update_irq(void *private);
210 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
211
212 void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data);
213 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
214 ktime_t expires, ktime_t period);
215 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
216 int rtc_read_offset(struct rtc_device *rtc, long *offset);
217 int rtc_set_offset(struct rtc_device *rtc, long offset);
218 void rtc_timer_do_work(struct work_struct *work);
219
is_leap_year(unsigned int year)220 static inline bool is_leap_year(unsigned int year)
221 {
222 return (!(year % 4) && (year % 100)) || !(year % 400);
223 }
224
225 /* Determine if we can call to driver to set the time. Drivers can only be
226 * called to set a second aligned time value, and the field set_offset_nsec
227 * specifies how far away from the second aligned time to call the driver.
228 *
229 * This also computes 'to_set' which is the time we are trying to set, and has
230 * a zero in tv_nsecs, such that:
231 * to_set - set_delay_nsec == now +/- FUZZ
232 *
233 */
rtc_tv_nsec_ok(s64 set_offset_nsec,struct timespec64 * to_set,const struct timespec64 * now)234 static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
235 struct timespec64 *to_set,
236 const struct timespec64 *now)
237 {
238 /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
239 const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
240 struct timespec64 delay = {.tv_sec = 0,
241 .tv_nsec = set_offset_nsec};
242
243 *to_set = timespec64_add(*now, delay);
244
245 if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
246 to_set->tv_nsec = 0;
247 return true;
248 }
249
250 if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
251 to_set->tv_sec++;
252 to_set->tv_nsec = 0;
253 return true;
254 }
255 return false;
256 }
257
258 #define rtc_register_device(device) \
259 __rtc_register_device(THIS_MODULE, device)
260
261 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
262 extern int rtc_hctosys_ret;
263 #else
264 #define rtc_hctosys_ret -ENODEV
265 #endif
266
267 #ifdef CONFIG_RTC_NVMEM
268 int rtc_nvmem_register(struct rtc_device *rtc,
269 struct nvmem_config *nvmem_config);
270 void rtc_nvmem_unregister(struct rtc_device *rtc);
271 #else
rtc_nvmem_register(struct rtc_device * rtc,struct nvmem_config * nvmem_config)272 static inline int rtc_nvmem_register(struct rtc_device *rtc,
273 struct nvmem_config *nvmem_config)
274 {
275 return 0;
276 }
rtc_nvmem_unregister(struct rtc_device * rtc)277 static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
278 #endif
279
280 #endif /* _LINUX_RTC_H_ */
281