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Star64_linux/include/linux/rtc.h
Jason Gunthorpe 0f295b0650 rtc: Allow rtc drivers to specify the tv_nsec value for ntp 
ntp is currently hardwired to try and call the rtc set when wall clock
tv_nsec is 0.5 seconds. This historical behaviour works well with certain
PC RTCs, but is not universal to all rtc hardware.

Change how this works by introducing the driver specific concept of
set_offset_nsec, the delay between current wall clock time and the target
time to set (with a 0 tv_nsecs).

For x86-style CMOS set_offset_nsec should be -0.5 s which causes the last
second to be written 0.5 s after it has started.

For compat with the old rtc_set_ntp_time, the value is defaulted to
+ 0.5 s, which causes the next second to be written 0.5s before it starts,
as things were before this patch.

Testing shows many non-x86 RTCs would like set_offset_nsec ~= 0,
so ultimately each RTC driver should set the set_offset_nsec according
to its needs, and non x86 architectures should stop using
update_persistent_clock64 in order to access this feature.
Future patches will revise the drivers as needed.

Since CMOS and RTC now have very different handling they are split
into two dedicated code paths, sharing the support code, and ifdefs
are replaced with IS_ENABLED.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Miroslav Lichvar <mlichvar@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <stephen.boyd@linaro.org>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2017-10-30 15:03:24 -07:00

274 lines
8.7 KiB
C
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/*
* Generic RTC interface.
* This version contains the part of the user interface to the Real Time Clock
* service. It is used with both the legacy mc146818 and also EFI
* Struct rtc_time and first 12 ioctl by Paul Gortmaker, 1996 - separated out
* from <linux/mc146818rtc.h> to this file for 2.4 kernels.
*
* Copyright (C) 1999 Hewlett-Packard Co.
* Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
*/
#ifndef _LINUX_RTC_H_
#define _LINUX_RTC_H_
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/nvmem-provider.h>
#include <uapi/linux/rtc.h>
extern int rtc_month_days(unsigned int month, unsigned int year);
extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
extern int rtc_valid_tm(struct rtc_time *tm);
extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
ktime_t rtc_tm_to_ktime(struct rtc_time tm);
struct rtc_time rtc_ktime_to_tm(ktime_t kt);
/*
* rtc_tm_sub - Return the difference in seconds.
*/
static inline time64_t rtc_tm_sub(struct rtc_time *lhs, struct rtc_time *rhs)
{
return rtc_tm_to_time64(lhs) - rtc_tm_to_time64(rhs);
}
static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
{
rtc_time64_to_tm(time, tm);
}
static inline int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
{
*time = rtc_tm_to_time64(tm);
return 0;
}
#include <linux/device.h>
#include <linux/seq_file.h>
#include <linux/cdev.h>
#include <linux/poll.h>
#include <linux/mutex.h>
#include <linux/timerqueue.h>
#include <linux/workqueue.h>
extern struct class *rtc_class;
/*
* For these RTC methods the device parameter is the physical device
* on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
* was passed to rtc_device_register(). Its driver_data normally holds
* device state, including the rtc_device pointer for the RTC.
*
* Most of these methods are called with rtc_device.ops_lock held,
* through the rtc_*(struct rtc_device *, ...) calls.
*
* The (current) exceptions are mostly filesystem hooks:
* - the proc() hook for procfs
* - non-ioctl() chardev hooks: open(), release(), read_callback()
*
* REVISIT those periodic irq calls *do* have ops_lock when they're
* issued through ioctl() ...
*/
struct rtc_class_ops {
int (*ioctl)(struct device *, unsigned int, unsigned long);
int (*read_time)(struct device *, struct rtc_time *);
int (*set_time)(struct device *, struct rtc_time *);
int (*read_alarm)(struct device *, struct rtc_wkalrm *);
int (*set_alarm)(struct device *, struct rtc_wkalrm *);
int (*proc)(struct device *, struct seq_file *);
int (*set_mmss64)(struct device *, time64_t secs);
int (*set_mmss)(struct device *, unsigned long secs);
int (*read_callback)(struct device *, int data);
int (*alarm_irq_enable)(struct device *, unsigned int enabled);
int (*read_offset)(struct device *, long *offset);
int (*set_offset)(struct device *, long offset);
};
#define RTC_DEVICE_NAME_SIZE 20
typedef struct rtc_task {
void (*func)(void *private_data);
void *private_data;
} rtc_task_t;
struct rtc_timer {
struct rtc_task task;
struct timerqueue_node node;
ktime_t period;
int enabled;
};
/* flags */
#define RTC_DEV_BUSY 0
struct rtc_device {
struct device dev;
struct module *owner;
int id;
const struct rtc_class_ops *ops;
struct mutex ops_lock;
struct cdev char_dev;
unsigned long flags;
unsigned long irq_data;
spinlock_t irq_lock;
wait_queue_head_t irq_queue;
struct fasync_struct *async_queue;
struct rtc_task *irq_task;
spinlock_t irq_task_lock;
int irq_freq;
int max_user_freq;
struct timerqueue_head timerqueue;
struct rtc_timer aie_timer;
struct rtc_timer uie_rtctimer;
struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
int pie_enabled;
struct work_struct irqwork;
/* Some hardware can't support UIE mode */
int uie_unsupported;
/* Number of nsec it takes to set the RTC clock. This influences when
* the set ops are called. An offset:
* - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
* - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
* - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
*/
long set_offset_nsec;
bool registered;
struct nvmem_config *nvmem_config;
struct nvmem_device *nvmem;
/* Old ABI support */
bool nvram_old_abi;
struct bin_attribute *nvram;
#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
struct work_struct uie_task;
struct timer_list uie_timer;
/* Those fields are protected by rtc->irq_lock */
unsigned int oldsecs;
unsigned int uie_irq_active:1;
unsigned int stop_uie_polling:1;
unsigned int uie_task_active:1;
unsigned int uie_timer_active:1;
#endif
};
#define to_rtc_device(d) container_of(d, struct rtc_device, dev)
extern struct rtc_device *rtc_device_register(const char *name,
struct device *dev,
const struct rtc_class_ops *ops,
struct module *owner);
extern struct rtc_device *devm_rtc_device_register(struct device *dev,
const char *name,
const struct rtc_class_ops *ops,
struct module *owner);
struct rtc_device *devm_rtc_allocate_device(struct device *dev);
int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
extern void rtc_device_unregister(struct rtc_device *rtc);
extern void devm_rtc_device_unregister(struct device *dev,
struct rtc_device *rtc);
extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
extern int rtc_read_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern int rtc_set_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern int rtc_initialize_alarm(struct rtc_device *rtc,
struct rtc_wkalrm *alrm);
extern void rtc_update_irq(struct rtc_device *rtc,
unsigned long num, unsigned long events);
extern struct rtc_device *rtc_class_open(const char *name);
extern void rtc_class_close(struct rtc_device *rtc);
extern int rtc_irq_register(struct rtc_device *rtc,
struct rtc_task *task);
extern void rtc_irq_unregister(struct rtc_device *rtc,
struct rtc_task *task);
extern int rtc_irq_set_state(struct rtc_device *rtc,
struct rtc_task *task, int enabled);
extern int rtc_irq_set_freq(struct rtc_device *rtc,
struct rtc_task *task, int freq);
extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
unsigned int enabled);
void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
void rtc_aie_update_irq(void *private);
void rtc_uie_update_irq(void *private);
enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
int rtc_register(rtc_task_t *task);
int rtc_unregister(rtc_task_t *task);
int rtc_control(rtc_task_t *t, unsigned int cmd, unsigned long arg);
void rtc_timer_init(struct rtc_timer *timer, void (*f)(void *p), void *data);
int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
ktime_t expires, ktime_t period);
void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
int rtc_read_offset(struct rtc_device *rtc, long *offset);
int rtc_set_offset(struct rtc_device *rtc, long offset);
void rtc_timer_do_work(struct work_struct *work);
static inline bool is_leap_year(unsigned int year)
{
return (!(year % 4) && (year % 100)) || !(year % 400);
}
/* Determine if we can call to driver to set the time. Drivers can only be
* called to set a second aligned time value, and the field set_offset_nsec
* specifies how far away from the second aligned time to call the driver.
*
* This also computes 'to_set' which is the time we are trying to set, and has
* a zero in tv_nsecs, such that:
* to_set - set_delay_nsec == now +/- FUZZ
*
*/
static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
struct timespec64 *to_set,
const struct timespec64 *now)
{
/* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
struct timespec64 delay = {.tv_sec = 0,
.tv_nsec = set_offset_nsec};
*to_set = timespec64_add(*now, delay);
if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
to_set->tv_nsec = 0;
return true;
}
if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
to_set->tv_sec++;
to_set->tv_nsec = 0;
return true;
}
return false;
}
#define rtc_register_device(device) \
__rtc_register_device(THIS_MODULE, device)
#ifdef CONFIG_RTC_HCTOSYS_DEVICE
extern int rtc_hctosys_ret;
#else
#define rtc_hctosys_ret -ENODEV
#endif
#endif /* _LINUX_RTC_H_ */
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