include/linux/rtc.h

   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 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        -2208989361LL /* 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
 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  */
 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
 272 static inline int rtc_nvmem_register(struct rtc_device *rtc,
 273                                      struct nvmem_config *nvmem_config)
 274 {
 275         return 0;
 276 }
 277 static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
 278 #endif
 279
 280 #endif /* _LINUX_RTC_H_ */