From cc947f2b9c04113d84eeef67cc7c6326e1982019 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 16 Nov 2020 10:53:38 +0100 Subject: timers: Make run_local_timers() static No users outside of the timer code. Move the caller below this function to avoid a pointless forward declaration. Signed-off-by: Thomas Gleixner --- include/linux/timer.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/timer.h b/include/linux/timer.h index d10bc7e73b41..fda13c9d1256 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -193,7 +193,6 @@ extern int try_to_del_timer_sync(struct timer_list *timer); #define del_singleshot_timer_sync(t) del_timer_sync(t) extern void init_timers(void); -extern void run_local_timers(void); struct hrtimer; extern enum hrtimer_restart it_real_fn(struct hrtimer *); -- cgit v1.2.3 From 66981c37b3199d293c58f84cf2366e86a06e1a3d Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Mon, 16 Nov 2020 11:18:14 +0100 Subject: hrtimer: Fix kernel-doc markups The hrtimer_get_remaining() markup is documenting, instead, __hrtimer_get_remaining(), as it is placed at the C file. In order to properly document it, a kernel-doc markup is needed together with the function prototype. So, add a new one, while preserving the existing one, just fixing the function name. The hrtimer_is_queued prototype has a typo: it is using '=' instead of '-' to split: identifier - description as required by kernel-doc markup. Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/9dc87808c2fd07b7e050bafcd033c5ef05808fea.1605521731.git.mchehab+huawei@kernel.org --- include/linux/hrtimer.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h index 107cedd7019a..bb5e7b0a4274 100644 --- a/include/linux/hrtimer.h +++ b/include/linux/hrtimer.h @@ -447,6 +447,10 @@ static inline void hrtimer_restart(struct hrtimer *timer) /* Query timers: */ extern ktime_t __hrtimer_get_remaining(const struct hrtimer *timer, bool adjust); +/** + * hrtimer_get_remaining - get remaining time for the timer + * @timer: the timer to read + */ static inline ktime_t hrtimer_get_remaining(const struct hrtimer *timer) { return __hrtimer_get_remaining(timer, false); @@ -458,7 +462,7 @@ extern u64 hrtimer_next_event_without(const struct hrtimer *exclude); extern bool hrtimer_active(const struct hrtimer *timer); /** - * hrtimer_is_queued = check, whether the timer is on one of the queues + * hrtimer_is_queued - check, whether the timer is on one of the queues * @timer: Timer to check * * Returns: True if the timer is queued, false otherwise -- cgit v1.2.3 From 0fce2e02a29ca5420472f03d3f2858eedded3fe7 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E5=91=A8=E7=90=B0=E6=9D=B0=20=28Zhou=20Yanjie=29?= Date: Mon, 26 Oct 2020 23:58:42 +0800 Subject: dt-bindings: timer: Add new OST support for the upcoming new driver. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The new OST has one global timer and two or four percpu timers, so there will be three combinations in the upcoming new OST driver: the original GLOBAL_TIMER + PERCPU_TIMER, the new GLOBAL_TIMER + PERCPU_TIMER0/1 and GLOBAL_TIMER + PERCPU_TIMER0/1/2/3, For this, add the macro definition about OST_CLK_PERCPU_TIMER0/1/2/3. And in order to ensure that all the combinations work normally, the original ABI values of OST_CLK_PERCPU_TIMER and OST_CLK_GLOBAL_TIMER need to be exchanged to ensure that in any combinations, the clock can be registered (by calling clk_hw_register()) from index 0. Before this patch, OST_CLK_PERCPU_TIMER and OST_CLK_GLOBAL_TIMER are only used in two places, one is when using "assigned-clocks" to configure the clocks in the DTS file; the other is when registering the clocks in the sysost driver. When the values of these two ABIs are exchanged, the ABI value used by sysost driver when registering the clock, and the ABI value used by DTS when configuring the clock using "assigned-clocks" will also change accordingly. Therefore, there is no situation that causes the wrong clock to the configured. Therefore, exchanging ABI values will not cause errors in the existing codes when registering and configuring the clocks. Currently, in the mainline, only X1000 and X1830 are using sysost driver, and the upcoming X2000 will also use sysost driver. This patch has been tested on all three SoCs and all works fine. Tested-by: 周正 (Zhou Zheng) Signed-off-by: 周琰杰 (Zhou Yanjie) Reviewed-by: Rob Herring Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20201026155842.10196-2-zhouyanjie@wanyeetech.com --- include/dt-bindings/clock/ingenic,sysost.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/dt-bindings/clock/ingenic,sysost.h b/include/dt-bindings/clock/ingenic,sysost.h index 9ac88e90babf..063791b01ab3 100644 --- a/include/dt-bindings/clock/ingenic,sysost.h +++ b/include/dt-bindings/clock/ingenic,sysost.h @@ -1,12 +1,16 @@ /* SPDX-License-Identifier: GPL-2.0 */ /* - * This header provides clock numbers for the ingenic,tcu DT binding. + * This header provides clock numbers for the Ingenic OST DT binding. */ #ifndef __DT_BINDINGS_CLOCK_INGENIC_OST_H__ #define __DT_BINDINGS_CLOCK_INGENIC_OST_H__ -#define OST_CLK_PERCPU_TIMER 0 -#define OST_CLK_GLOBAL_TIMER 1 +#define OST_CLK_PERCPU_TIMER 1 +#define OST_CLK_GLOBAL_TIMER 0 +#define OST_CLK_PERCPU_TIMER0 1 +#define OST_CLK_PERCPU_TIMER1 2 +#define OST_CLK_PERCPU_TIMER2 3 +#define OST_CLK_PERCPU_TIMER3 4 #endif /* __DT_BINDINGS_CLOCK_INGENIC_OST_H__ */ -- cgit v1.2.3 From c9e6189fb03123a7dfb93589280347b46f30b161 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 6 Dec 2020 22:46:18 +0100 Subject: ntp: Make the RTC synchronization more reliable Miroslav reported that the periodic RTC synchronization in the NTP code fails more often than not to hit the specified update window. The reason is that the code uses delayed_work to schedule the update which needs to be in thread context as the underlying RTC might be connected via a slow bus, e.g. I2C. In the update function it verifies whether the current time is correct vs. the requirements of the underlying RTC. But delayed_work is using the timer wheel for scheduling which is inaccurate by design. Depending on the distance to the expiry the wheel gets less granular to allow batching and to avoid the cascading of the original timer wheel. See 500462a9de65 ("timers: Switch to a non-cascading wheel") and the code for further details. The code already deals with this by splitting the 660 seconds period into a long 659 seconds timer and then retrying with a smaller delta. But looking at the actual granularities of the timer wheel (which depend on the HZ configuration) the 659 seconds timer ends up in an outer wheel level and is affected by a worst case granularity of: HZ Granularity 1000 32s 250 16s 100 40s So the initial timer can be already off by max 12.5% which is not a big issue as the period of the sync is defined as ~11 minutes. The fine grained second attempt schedules to the desired update point with a timer expiring less than a second from now. Depending on the actual delta and the HZ setting even the second attempt can end up in outer wheel levels which have a large enough granularity to make the correctness check fail. As this is a fundamental property of the timer wheel there is no way to make this more accurate short of iterating in one jiffies steps towards the update point. Switch it to an hrtimer instead which schedules the actual update work. The hrtimer will expire precisely (max 1 jiffie delay when high resolution timers are not available). The actual scheduling delay of the work is the same as before. The update is triggered from do_adjtimex() which is a bit racy but not much more racy than it was before: if (ntp_synced()) queue_delayed_work(system_power_efficient_wq, &sync_work, 0); which is racy when the work is currently executed and has not managed to reschedule itself. This becomes now: if (ntp_synced() && !hrtimer_is_queued(&sync_hrtimer)) queue_work(system_power_efficient_wq, &sync_work, 0); which is racy when the hrtimer has expired and the work is currently executed and has not yet managed to rearm the hrtimer. Not a big problem as it just schedules work for nothing. The new implementation has a safe guard in place to catch the case where the hrtimer is queued on entry to the work function and avoids an extra update attempt of the RTC that way. Reported-by: Miroslav Lichvar Signed-off-by: Thomas Gleixner Tested-by: Miroslav Lichvar Reviewed-by: Jason Gunthorpe Acked-by: Alexandre Belloni Link: https://lore.kernel.org/r/20201206220542.062910520@linutronix.de --- include/linux/timex.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include') diff --git a/include/linux/timex.h b/include/linux/timex.h index ce0859763670..9c2e54faf9b7 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -157,7 +157,6 @@ extern int do_clock_adjtime(const clockid_t which_clock, struct __kernel_timex * extern void hardpps(const struct timespec64 *, const struct timespec64 *); int read_current_timer(unsigned long *timer_val); -void ntp_notify_cmos_timer(void); /* The clock frequency of the i8253/i8254 PIT */ #define PIT_TICK_RATE 1193182ul -- cgit v1.2.3 From 33e62e832384c8cb523044e0e9d99d7133f98e93 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 6 Dec 2020 22:46:19 +0100 Subject: ntp, rtc: Move rtc_set_ntp_time() to ntp code rtc_set_ntp_time() is not really RTC functionality as the code is just a user of RTC. Move it into the NTP code which allows further cleanups. Requested-by: Alexandre Belloni Signed-off-by: Thomas Gleixner Reviewed-by: Jason Gunthorpe Acked-by: Alexandre Belloni Link: https://lore.kernel.org/r/20201206220542.166871172@linutronix.de --- include/linux/rtc.h | 34 ---------------------------------- 1 file changed, 34 deletions(-) (limited to 'include') diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 22d1575e4991..ff62680b48ca 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -165,7 +165,6 @@ int __rtc_register_device(struct module *owner, 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); @@ -205,39 +204,6 @@ 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) -- cgit v1.2.3 From 69eca258c85000564577642ba28335eb4e1df8f0 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sun, 6 Dec 2020 22:46:20 +0100 Subject: ntp: Make the RTC sync offset less obscure The current RTC set_offset_nsec value is not really intuitive to understand. tsched twrite(t2.tv_sec - 1) t2 (seconds increment) The offset is calculated from twrite based on the assumption that t2 - twrite == 1s. That means for the MC146818 RTC the offset needs to be negative so that the write happens 500ms before t2. It's easier to understand when the whole calculation is based on t2. That avoids negative offsets and the meaning is obvious: t2 - twrite: The time defined by the chip when seconds increment after the write. twrite - tsched: The time for the transport to the point where the chip is updated. ==> set_offset_nsec = t2 - tsched ttransport = twrite - tsched tRTCinc = t2 - twrite ==> set_offset_nsec = ttransport + tRTCinc tRTCinc is a chip property and can be obtained from the data sheet. ttransport depends on how the RTC is connected. It is close to 0 for directly accessible RTCs. For RTCs behind a slow bus, e.g. i2c, it's the time required to send the update over the bus. This can be estimated or even calibrated, but that's a different problem. Adjust the implementation and update comments accordingly. Signed-off-by: Thomas Gleixner Acked-by: Alexandre Belloni Link: https://lore.kernel.org/r/20201206220542.263204937@linutronix.de --- include/linux/rtc.h | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-) (limited to 'include') diff --git a/include/linux/rtc.h b/include/linux/rtc.h index ff62680b48ca..b829382de6c3 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -110,13 +110,36 @@ struct rtc_device { /* 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 + /* + * This offset specifies the update timing of the RTC. + * + * tsched t1 write(t2.tv_sec - 1sec)) t2 RTC increments seconds + * + * The offset defines how tsched is computed so that the write to + * the RTC (t2.tv_sec - 1sec) is correct versus the time required + * for the transport of the write and the time which the RTC needs + * to increment seconds the first time after the write (t2). + * + * For direct accessible RTCs tsched ~= t1 because the write time + * is negligible. For RTCs behind slow busses the transport time is + * significant and has to be taken into account. + * + * The time between the write (t1) and the first increment after + * the write (t2) is RTC specific. For a MC146818 RTC it's 500ms, + * for many others it's exactly 1 second. Consult the datasheet. + * + * The value of this offset is also used to calculate the to be + * written value (t2.tv_sec - 1sec) at tsched. + * + * The default value for this is NSEC_PER_SEC + 10 msec default + * transport time. The offset can be adjusted by drivers so the + * calculation for the to be written value at tsched becomes + * correct: + * + * newval = tsched + set_offset_nsec - NSEC_PER_SEC + * and (tsched + set_offset_nsec) % NSEC_PER_SEC == 0 */ - long set_offset_nsec; + unsigned long set_offset_nsec; bool registered; -- cgit v1.2.3 From 3cabca87b329cbcbdf295be0094adbd72c7b1f67 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 12 Dec 2020 18:29:20 +0100 Subject: ntp: Fix prototype in the !CONFIG_GENERIC_CMOS_UPDATE case In the !CONFIG_GENERIC_CMOS_UPDATE case the update_persistent_clock64() function gets defined as a stub in ntp.c - make the prototype in conditional on CONFIG_GENERIC_CMOS_UPDATE as well. Fixes: 76e87d96b30b5 ("ntp: Consolidate the RTC update implementation") Signed-off-by: Ingo Molnar Acked-by: Thomas Gleixner --- include/linux/timekeeping.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index 7f7e4a3f4394..929d3f3937c0 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -303,6 +303,8 @@ extern int persistent_clock_is_local; extern void read_persistent_clock64(struct timespec64 *ts); void read_persistent_wall_and_boot_offset(struct timespec64 *wall_clock, struct timespec64 *boot_offset); +#ifdef CONFIG_GENERIC_CMOS_UPDATE extern int update_persistent_clock64(struct timespec64 now); +#endif #endif -- cgit v1.2.3