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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()
 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 (*alarm_irq_enable)(struct device *, unsigned int enabled);
 83         int (*read_offset)(struct device *, long *offset);
 84         int (*set_offset)(struct device *, long offset);
 85 };
 86 
 87 struct rtc_device;
 88 
 89 struct rtc_timer {
 90         struct timerqueue_node node;
 91         ktime_t period;
 92         void (*func)(struct rtc_device *rtc);
 93         struct rtc_device *rtc;
 94         int enabled;
 95 };
 96 
 97 /* flags */
 98 #define RTC_DEV_BUSY 0
 99 
100 struct rtc_device {
101         struct device dev;
102         struct module *owner;
103 
104         int id;
105 
106         const struct rtc_class_ops *ops;
107         struct mutex ops_lock;
108 
109         struct cdev char_dev;
110         unsigned long flags;
111 
112         unsigned long irq_data;
113         spinlock_t irq_lock;
114         wait_queue_head_t irq_queue;
115         struct fasync_struct *async_queue;
116 
117         int irq_freq;
118         int max_user_freq;
119 
120         struct timerqueue_head timerqueue;
121         struct rtc_timer aie_timer;
122         struct rtc_timer uie_rtctimer;
123         struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
124         int pie_enabled;
125         struct work_struct irqwork;
126         /* Some hardware can't support UIE mode */
127         int uie_unsupported;
128 
129         /* Number of nsec it takes to set the RTC clock. This influences when
130          * the set ops are called. An offset:
131          *   - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
132          *   - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
133          *   - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
134          */
135         long set_offset_nsec;
136 
137         bool registered;
138 
139         /* Old ABI support */
140         bool nvram_old_abi;
141         struct bin_attribute *nvram;
142 
143         time64_t range_min;
144         timeu64_t range_max;
145         time64_t start_secs;
146         time64_t offset_secs;
147         bool set_start_time;
148 
149 #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
150         struct work_struct uie_task;
151         struct timer_list uie_timer;
152         /* Those fields are protected by rtc->irq_lock */
153         unsigned int oldsecs;
154         unsigned int uie_irq_active:1;
155         unsigned int stop_uie_polling:1;
156         unsigned int uie_task_active:1;
157         unsigned int uie_timer_active:1;
158 #endif
159 };
160 #define to_rtc_device(d) container_of(d, struct rtc_device, dev)
161 
162 #define rtc_lock(d) mutex_lock(&d->ops_lock)
163 #define rtc_unlock(d) mutex_unlock(&d->ops_lock)
164 
165 /* useful timestamps */
166 #define RTC_TIMESTAMP_BEGIN_0000        -62167219200ULL /* 0000-01-01 00:00:00 */
167 #define RTC_TIMESTAMP_BEGIN_1900        -2208988800LL /* 1900-01-01 00:00:00 */
168 #define RTC_TIMESTAMP_BEGIN_2000        946684800LL /* 2000-01-01 00:00:00 */
169 #define RTC_TIMESTAMP_END_2063          2966371199LL /* 2063-12-31 23:59:59 */
170 #define RTC_TIMESTAMP_END_2099          4102444799LL /* 2099-12-31 23:59:59 */
171 #define RTC_TIMESTAMP_END_2199          7258118399LL /* 2199-12-31 23:59:59 */
172 #define RTC_TIMESTAMP_END_9999          253402300799LL /* 9999-12-31 23:59:59 */
173 
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 
181 extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
182 extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
183 extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
184 int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
185 extern int rtc_read_alarm(struct rtc_device *rtc,
186                         struct rtc_wkalrm *alrm);
187 extern int rtc_set_alarm(struct rtc_device *rtc,
188                                 struct rtc_wkalrm *alrm);
189 extern int rtc_initialize_alarm(struct rtc_device *rtc,
190                                 struct rtc_wkalrm *alrm);
191 extern void rtc_update_irq(struct rtc_device *rtc,
192                         unsigned long num, unsigned long events);
193 
194 extern struct rtc_device *rtc_class_open(const char *name);
195 extern void rtc_class_close(struct rtc_device *rtc);
196 
197 extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
198 extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
199 extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
200 extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
201 extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
202                                                 unsigned int enabled);
203 
204 void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
205 void rtc_aie_update_irq(struct rtc_device *rtc);
206 void rtc_uie_update_irq(struct rtc_device *rtc);
207 enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
208 
209 void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
210                     struct rtc_device *rtc);
211 int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
212                     ktime_t expires, ktime_t period);
213 void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
214 int rtc_read_offset(struct rtc_device *rtc, long *offset);
215 int rtc_set_offset(struct rtc_device *rtc, long offset);
216 void rtc_timer_do_work(struct work_struct *work);
217 
218 static inline bool is_leap_year(unsigned int year)
219 {
220         return (!(year % 4) && (year % 100)) || !(year % 400);
221 }
222 
223 /* Determine if we can call to driver to set the time. Drivers can only be
224  * called to set a second aligned time value, and the field set_offset_nsec
225  * specifies how far away from the second aligned time to call the driver.
226  *
227  * This also computes 'to_set' which is the time we are trying to set, and has
228  * a zero in tv_nsecs, such that:
229  *    to_set - set_delay_nsec == now +/- FUZZ
230  *
231  */
232 static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
233                                   struct timespec64 *to_set,
234                                   const struct timespec64 *now)
235 {
236         /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
237         const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
238         struct timespec64 delay = {.tv_sec = 0,
239                                    .tv_nsec = set_offset_nsec};
240 
241         *to_set = timespec64_add(*now, delay);
242 
243         if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
244                 to_set->tv_nsec = 0;
245                 return true;
246         }
247 
248         if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
249                 to_set->tv_sec++;
250                 to_set->tv_nsec = 0;
251                 return true;
252         }
253         return false;
254 }
255 
256 #define rtc_register_device(device) \
257         __rtc_register_device(THIS_MODULE, device)
258 
259 #ifdef CONFIG_RTC_HCTOSYS_DEVICE
260 extern int rtc_hctosys_ret;
261 #else
262 #define rtc_hctosys_ret -ENODEV
263 #endif
264 
265 #ifdef CONFIG_RTC_NVMEM
266 int rtc_nvmem_register(struct rtc_device *rtc,
267                        struct nvmem_config *nvmem_config);
268 void rtc_nvmem_unregister(struct rtc_device *rtc);
269 #else
270 static inline int rtc_nvmem_register(struct rtc_device *rtc,
271                                      struct nvmem_config *nvmem_config)
272 {
273         return 0;
274 }
275 static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
276 #endif
277 
278 #ifdef CONFIG_RTC_INTF_SYSFS
279 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
280 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
281 #else
282 static inline
283 int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
284 {
285         return 0;
286 }
287 
288 static inline
289 int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
290 {
291         return 0;
292 }
293 #endif
294 #endif /* _LINUX_RTC_H_ */
295 

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