From 6b2e29977518ec13ef3022f234ff8f3014c243da Mon Sep 17 00:00:00 2001 From: Lakshmi Sowjanya D Date: Mon, 13 May 2024 16:08:02 +0530 Subject: timekeeping: Provide infrastructure for converting to/from a base clock Hardware time stamps like provided by PTP clock implementations are based on a clock which feeds both the PCIe device and the system clock. For further processing the underlying hardwarre clock timestamp must be converted to the system clock. Right now this requires drivers to invoke an architecture specific conversion function, e.g. to convert the ART (Always Running Timer) timestamp to a TSC timestamp. As the system clock is aware of the underlying base clock, this can be moved to the core code by providing a base clock property for the system clock which contains the conversion factors and assigning a clocksource ID to the base clock. Add the required data structures and the conversion infrastructure in the core code to prepare for converting X86 and the related PTP drivers over. [ tglx: Added a missing READ_ONCE(). Massaged change log ] Co-developed-by: Thomas Gleixner Signed-off-by: Thomas Gleixner Co-developed-by: Christopher S. Hall Signed-off-by: Christopher S. Hall Signed-off-by: Lakshmi Sowjanya D Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20240513103813.5666-2-lakshmi.sowjanya.d@intel.com --- include/linux/clocksource.h | 27 +++++++++++++++++++++++++++ include/linux/timekeeping.h | 2 ++ 2 files changed, 29 insertions(+) (limited to 'include/linux') diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 0ad8b550bb4b..d35b677b08fe 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -21,6 +21,7 @@ #include #include +struct clocksource_base; struct clocksource; struct module; @@ -50,6 +51,7 @@ struct module; * multiplication * @name: Pointer to clocksource name * @list: List head for registration (internal) + * @freq_khz: Clocksource frequency in khz. * @rating: Rating value for selection (higher is better) * To avoid rating inflation the following * list should give you a guide as to how @@ -70,6 +72,8 @@ struct module; * validate the clocksource from which the snapshot was * taken. * @flags: Flags describing special properties + * @base: Hardware abstraction for clock on which a clocksource + * is based * @enable: Optional function to enable the clocksource * @disable: Optional function to disable the clocksource * @suspend: Optional suspend function for the clocksource @@ -107,10 +111,12 @@ struct clocksource { u64 max_cycles; const char *name; struct list_head list; + u32 freq_khz; int rating; enum clocksource_ids id; enum vdso_clock_mode vdso_clock_mode; unsigned long flags; + struct clocksource_base *base; int (*enable)(struct clocksource *cs); void (*disable)(struct clocksource *cs); @@ -306,4 +312,25 @@ static inline unsigned int clocksource_get_max_watchdog_retry(void) void clocksource_verify_percpu(struct clocksource *cs); +/** + * struct clocksource_base - hardware abstraction for clock on which a clocksource + * is based + * @id: Defaults to CSID_GENERIC. The id value is used for conversion + * functions which require that the current clocksource is based + * on a clocksource_base with a particular ID in certain snapshot + * functions to allow callers to validate the clocksource from + * which the snapshot was taken. + * @freq_khz: Nominal frequency of the base clock in kHz + * @offset: Offset between the base clock and the clocksource + * @numerator: Numerator of the clock ratio between base clock and the clocksource + * @denominator: Denominator of the clock ratio between base clock and the clocksource + */ +struct clocksource_base { + enum clocksource_ids id; + u32 freq_khz; + u64 offset; + u32 numerator; + u32 denominator; +}; + #endif /* _LINUX_CLOCKSOURCE_H */ diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index 0ea7823b7f31..b2ee182d891e 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -310,10 +310,12 @@ struct system_device_crosststamp { * timekeeping code to verify comparability of two cycle values. * The default ID, CSID_GENERIC, does not identify a specific * clocksource. + * @use_nsecs: @cycles is in nanoseconds. */ struct system_counterval_t { u64 cycles; enum clocksource_ids cs_id; + bool use_nsecs; }; /* -- cgit v1.2.3 From 3a52886c8f972c3a5b70bfec330c71817cd7fc63 Mon Sep 17 00:00:00 2001 From: Lakshmi Sowjanya D Date: Mon, 13 May 2024 16:08:03 +0530 Subject: x86/tsc: Provide ART base clock information for TSC The core code provides a new mechanism to allow conversion between ART and TSC. This allows to replace the x86 specific ART/TSC conversion functions. Prepare for removal by filling in the base clock conversion information for ART and associating the base clock to the TSC clocksource. The existing conversion functions will be removed once the usage sites are converted over to the new model. [ tglx: Massaged change log ] Co-developed-by: Thomas Gleixner Signed-off-by: Thomas Gleixner Co-developed-by: Christopher S. Hall Signed-off-by: Christopher S. Hall Signed-off-by: Lakshmi Sowjanya D Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20240513103813.5666-3-lakshmi.sowjanya.d@intel.com --- include/linux/clocksource_ids.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/clocksource_ids.h b/include/linux/clocksource_ids.h index a4fa3436940c..2bb4d8c2f1b0 100644 --- a/include/linux/clocksource_ids.h +++ b/include/linux/clocksource_ids.h @@ -9,6 +9,7 @@ enum clocksource_ids { CSID_X86_TSC_EARLY, CSID_X86_TSC, CSID_X86_KVM_CLK, + CSID_X86_ART, CSID_MAX, }; -- cgit v1.2.3 From 02ecee07ca30f76f2a0f1381661a688b8e501ab0 Mon Sep 17 00:00:00 2001 From: Lakshmi Sowjanya D Date: Mon, 13 May 2024 16:08:10 +0530 Subject: timekeeping: Add function to convert realtime to base clock PPS (Pulse Per Second) generates a hardware pulse every second based on CLOCK_REALTIME. This works fine when the pulse is generated in software from a hrtimer callback function. For hardware which generates the pulse by programming a timer it is required to convert CLOCK_REALTIME to the underlying hardware clock. The X86 Timed IO device is based on the Always Running Timer (ART), which is the base clock of the TSC, which is usually the system clocksource on X86. The core code already has functionality to convert base clock timestamps to system clocksource timestamps, but there is no support for converting the other way around. Provide the required functionality to support such devices in a generic way to avoid code duplication in drivers: 1) ktime_real_to_base_clock() to convert a CLOCK_REALTIME timestamp to a base clock timestamp 2) timekeeping_clocksource_has_base() to allow drivers to validate that the system clocksource is based on a particular clocksource ID. [ tglx: Simplify timekeeping_clocksource_has_base() and add missing READ_ONCE() ] Co-developed-by: Thomas Gleixner Signed-off-by: Thomas Gleixner Co-developed-by: Christopher S. Hall Signed-off-by: Christopher S. Hall Signed-off-by: Lakshmi Sowjanya D Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20240513103813.5666-10-lakshmi.sowjanya.d@intel.com --- include/linux/timekeeping.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index b2ee182d891e..fc12a9ba2c88 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -318,6 +318,10 @@ struct system_counterval_t { bool use_nsecs; }; +extern bool ktime_real_to_base_clock(ktime_t treal, + enum clocksource_ids base_id, u64 *cycles); +extern bool timekeeping_clocksource_has_base(enum clocksource_ids id); + /* * Get cross timestamp between system clock and device clock */ -- cgit v1.2.3 From 9403408e122628a6dc7154a95716f00dae3747c7 Mon Sep 17 00:00:00 2001 From: Christian Loehle Date: Mon, 17 Jun 2024 17:16:15 +0100 Subject: tick: Remove unnused tick_nohz_get_idle_calls() The function returns the idle calls counter for the current cpu and therefore usually isn't what the caller wants. It is unnused since commit 466a2b42d676 ("cpufreq: schedutil: Use idle_calls counter of the remote CPU") Signed-off-by: Christian Loehle Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20240617161615.49309-1-christian.loehle@arm.com --- include/linux/tick.h | 1 - 1 file changed, 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/tick.h b/include/linux/tick.h index 4924a33700b7..72744638c5b0 100644 --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -139,7 +139,6 @@ extern void tick_nohz_irq_exit(void); extern bool tick_nohz_idle_got_tick(void); extern ktime_t tick_nohz_get_next_hrtimer(void); extern ktime_t tick_nohz_get_sleep_length(ktime_t *delta_next); -extern unsigned long tick_nohz_get_idle_calls(void); extern unsigned long tick_nohz_get_idle_calls_cpu(int cpu); extern u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time); extern u64 get_cpu_iowait_time_us(int cpu, u64 *last_update_time); -- cgit v1.2.3 From 4bdc3eaa102b6bedb0800f76f53eca516d5cf20c Mon Sep 17 00:00:00 2001 From: Chris Packham Date: Wed, 10 Jul 2024 16:35:21 +1200 Subject: clocksource/drivers/realtek: Add timer driver for rtl-otto platforms The timer/counter block on the Realtek SoCs provides up to 5 timers. It also includes a watchdog timer which is handled by the realtek_otto_wdt.c driver. One timer will be used per CPU as a local clock event generator. An additional timer will be used as an overal stable clocksource. Signed-off-by: Markus Stockhausen Signed-off-by: Sander Vanheule Signed-off-by: Chris Packham Link: https://lore.kernel.org/r/20240710043524.1535151-8-chris.packham@alliedtelesis.co.nz Signed-off-by: Daniel Lezcano --- include/linux/cpuhotplug.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 7a5785f405b6..56b744dc1317 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -171,6 +171,7 @@ enum cpuhp_state { CPUHP_AP_ARMADA_TIMER_STARTING, CPUHP_AP_MIPS_GIC_TIMER_STARTING, CPUHP_AP_ARC_TIMER_STARTING, + CPUHP_AP_REALTEK_TIMER_STARTING, CPUHP_AP_RISCV_TIMER_STARTING, CPUHP_AP_CLINT_TIMER_STARTING, CPUHP_AP_CSKY_TIMER_STARTING, -- cgit v1.2.3