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TOMOYO Linux Cross Reference
Linux/include/linux/rtc.h

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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 
 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  */
 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 
 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 
 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 typedef struct rtc_task {
 91         void (*func)(void *private_data);
 92         void *private_data;
 93 } rtc_task_t;
 94 
 95 
 96 struct rtc_timer {
 97         struct rtc_task task;
 98         struct timerqueue_node node;
 99         ktime_t period;
100         int enabled;
101 };
102 
103 
104 /* flags */
105 #define RTC_DEV_BUSY 0
106 
107 struct rtc_device {
108         struct device dev;
109         struct module *owner;
110 
111         int id;
112 
113         const struct rtc_class_ops *ops;
114         struct mutex ops_lock;
115 
116         struct cdev char_dev;
117         unsigned long flags;
118 
119         unsigned long irq_data;
120         spinlock_t irq_lock;
121         wait_queue_head_t irq_queue;
122         struct fasync_struct *async_queue;
123 
124         struct rtc_task *irq_task;
125         spinlock_t irq_task_lock;
126         int irq_freq;
127         int max_user_freq;
128 
129         struct timerqueue_head timerqueue;
130         struct rtc_timer aie_timer;
131         struct rtc_timer uie_rtctimer;
132         struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
133         int pie_enabled;
134         struct work_struct irqwork;
135         /* Some hardware can't support UIE mode */
136         int uie_unsupported;
137 
138         /* Number of nsec it takes to set the RTC clock. This influences when
139          * the set ops are called. An offset:
140          *   - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
141          *   - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
142          *   - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
143          */
144         long set_offset_nsec;
145 
146         bool registered;
147 
148         struct nvmem_device *nvmem;
149         /* Old ABI support */
150         bool nvram_old_abi;
151         struct bin_attribute *nvram;
152 
153         time64_t range_min;
154         timeu64_t range_max;
155         time64_t start_secs;
156         time64_t offset_secs;
157         bool set_start_time;
158 
159 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
160         struct work_struct uie_task;
161         struct timer_list uie_timer;
162         /* Those fields are protected by rtc->irq_lock */
163         unsigned int oldsecs;
164         unsigned int uie_irq_active:1;
165         unsigned int stop_uie_polling:1;
166         unsigned int uie_task_active:1;
167         unsigned int uie_timer_active:1;
168 #endif
169 };
170 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
171 
172 /* useful timestamps */
173 #define RTC_TIMESTAMP_BEGIN_1900        -2208989361LL /* 1900-01-01 00:00:00 */
174 #define RTC_TIMESTAMP_BEGIN_2000        946684800LL /* 2000-01-01 00:00:00 */
175 #define RTC_TIMESTAMP_END_2099          4102444799LL /* 2099-12-31 23:59:59 */
176 
177 extern struct rtc_device *rtc_device_register(const char *name,
178                                         struct device *dev,
179                                         const struct rtc_class_ops *ops,
180                                         struct module *owner);
181 extern struct rtc_device *devm_rtc_device_register(struct device *dev,
182                                         const char *name,
183                                         const struct rtc_class_ops *ops,
184                                         struct module *owner);
185 struct rtc_device *devm_rtc_allocate_device(struct device *dev);
186 int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
187 extern void rtc_device_unregister(struct rtc_device *rtc);
188 extern void devm_rtc_device_unregister(struct device *dev,
189                                         struct rtc_device *rtc);
190 
191 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
192 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
193 extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
194 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
195 extern int rtc_read_alarm(struct rtc_device *rtc,
196                         struct rtc_wkalrm *alrm);
197 extern int rtc_set_alarm(struct rtc_device *rtc,
198                                 struct rtc_wkalrm *alrm);
199 extern int rtc_initialize_alarm(struct rtc_device *rtc,
200                                 struct rtc_wkalrm *alrm);
201 extern void rtc_update_irq(struct rtc_device *rtc,
202                         unsigned long num, unsigned long events);
203 
204 extern struct rtc_device *rtc_class_open(const char *name);
205 extern void rtc_class_close(struct rtc_device *rtc);
206 
207 extern int rtc_irq_register(struct rtc_device *rtc,
208                                 struct rtc_task *task);
209 extern void rtc_irq_unregister(struct rtc_device *rtc,
210                                 struct rtc_task *task);
211 extern int rtc_irq_set_state(struct rtc_device *rtc,
212                                 struct rtc_task *task, int enabled);
213 extern int rtc_irq_set_freq(struct rtc_device *rtc,
214                                 struct rtc_task *task, int freq);
215 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
216 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
217 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
218                                                 unsigned int enabled);
219 
220 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
221 void rtc_aie_update_irq(void *private);
222 void rtc_uie_update_irq(void *private);
223 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
224 
225 void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data);
226 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
227                     ktime_t expires, ktime_t period);
228 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
229 int rtc_read_offset(struct rtc_device *rtc, long *offset);
230 int rtc_set_offset(struct rtc_device *rtc, long offset);
231 void rtc_timer_do_work(struct work_struct *work);
232 
233 static inline bool is_leap_year(unsigned int year)
234 {
235         return (!(year % 4) && (year % 100)) || !(year % 400);
236 }
237 
238 /* Determine if we can call to driver to set the time. Drivers can only be
239  * called to set a second aligned time value, and the field set_offset_nsec
240  * specifies how far away from the second aligned time to call the driver.
241  *
242  * This also computes 'to_set' which is the time we are trying to set, and has
243  * a zero in tv_nsecs, such that:
244  *    to_set - set_delay_nsec == now +/- FUZZ
245  *
246  */
247 static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
248                                   struct timespec64 *to_set,
249                                   const struct timespec64 *now)
250 {
251         /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
252         const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
253         struct timespec64 delay = {.tv_sec = 0,
254                                    .tv_nsec = set_offset_nsec};
255 
256         *to_set = timespec64_add(*now, delay);
257 
258         if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
259                 to_set->tv_nsec = 0;
260                 return true;
261         }
262 
263         if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
264                 to_set->tv_sec++;
265                 to_set->tv_nsec = 0;
266                 return true;
267         }
268         return false;
269 }
270 
271 #define rtc_register_device(device) \
272         __rtc_register_device(THIS_MODULE, device)
273 
274 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
275 extern int rtc_hctosys_ret;
276 #else
277 #define rtc_hctosys_ret -ENODEV
278 #endif
279 
280 #ifdef CONFIG_RTC_NVMEM
281 int rtc_nvmem_register(struct rtc_device *rtc,
282                        struct nvmem_config *nvmem_config);
283 void rtc_nvmem_unregister(struct rtc_device *rtc);
284 #else
285 static inline int rtc_nvmem_register(struct rtc_device *rtc,
286                                      struct nvmem_config *nvmem_config)
287 {
288         return -ENODEV;
289 }
290 static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
291 #endif
292 
293 #endif /* _LINUX_RTC_H_ */
294 

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