From 4bf07f6562a01a488877e05267808da7147f44a5 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 22 Mar 2021 22:39:03 +0100 Subject: timekeeping, clocksource: Fix various typos in comments Fix ~56 single-word typos in timekeeping & clocksource code comments. Signed-off-by: Ingo Molnar Cc: Thomas Gleixner Cc: John Stultz Cc: Stephen Boyd Cc: Daniel Lezcano Cc: linux-kernel@vger.kernel.org --- include/linux/clocksource.h | 2 +- include/linux/timex.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 86d143db6523..a247b089ca78 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -70,7 +70,7 @@ struct module; * @mark_unstable: Optional function to inform the clocksource driver that * the watchdog marked the clocksource unstable * @tick_stable: Optional function called periodically from the watchdog - * code to provide stable syncrhonization points + * code to provide stable synchronization points * @wd_list: List head to enqueue into the watchdog list (internal) * @cs_last: Last clocksource value for clocksource watchdog * @wd_last: Last watchdog value corresponding to @cs_last diff --git a/include/linux/timex.h b/include/linux/timex.h index 9c2e54faf9b7..059b18eb1f1f 100644 --- a/include/linux/timex.h +++ b/include/linux/timex.h @@ -133,7 +133,7 @@ /* * kernel variables - * Note: maximum error = NTP synch distance = dispersion + delay / 2; + * Note: maximum error = NTP sync distance = dispersion + delay / 2; * estimated error = NTP dispersion. */ extern unsigned long tick_usec; /* USER_HZ period (usec) */ -- cgit v1.2.3 From 25de4ce5ed02994aea8bc111d133308f6fd62566 Mon Sep 17 00:00:00 2001 From: Tony Lindgren Date: Tue, 23 Mar 2021 09:43:26 +0200 Subject: clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 There is a timer wrap issue on dra7 for the ARM architected timer. In a typical clock configuration the timer fails to wrap after 388 days. To work around the issue, we need to use timer-ti-dm percpu timers instead. Let's configure dmtimer3 and 4 as percpu timers by default, and warn about the issue if the dtb is not configured properly. Let's do this as a single patch so it can be backported to v5.8 and later kernels easily. Note that this patch depends on earlier timer-ti-dm systimer posted mode fixes, and a preparatory clockevent patch "clocksource/drivers/timer-ti-dm: Prepare to handle dra7 timer wrap issue". For more information, please see the errata for "AM572x Sitara Processors Silicon Revisions 1.1, 2.0": https://www.ti.com/lit/er/sprz429m/sprz429m.pdf The concept is based on earlier reference patches done by Tero Kristo and Keerthy. Cc: Keerthy Cc: Tero Kristo Signed-off-by: Tony Lindgren Signed-off-by: Daniel Lezcano Link: https://lore.kernel.org/r/20210323074326.28302-3-tony@atomide.com --- arch/arm/boot/dts/dra7-l4.dtsi | 4 +- arch/arm/boot/dts/dra7.dtsi | 20 ++++++++ drivers/clocksource/timer-ti-dm-systimer.c | 76 ++++++++++++++++++++++++++++++ include/linux/cpuhotplug.h | 1 + 4 files changed, 99 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/arch/arm/boot/dts/dra7-l4.dtsi b/arch/arm/boot/dts/dra7-l4.dtsi index 3bf90d9e3335..a294a02f2d23 100644 --- a/arch/arm/boot/dts/dra7-l4.dtsi +++ b/arch/arm/boot/dts/dra7-l4.dtsi @@ -1168,7 +1168,7 @@ }; }; - target-module@34000 { /* 0x48034000, ap 7 46.0 */ + timer3_target: target-module@34000 { /* 0x48034000, ap 7 46.0 */ compatible = "ti,sysc-omap4-timer", "ti,sysc"; reg = <0x34000 0x4>, <0x34010 0x4>; @@ -1195,7 +1195,7 @@ }; }; - target-module@36000 { /* 0x48036000, ap 9 4e.0 */ + timer4_target: target-module@36000 { /* 0x48036000, ap 9 4e.0 */ compatible = "ti,sysc-omap4-timer", "ti,sysc"; reg = <0x36000 0x4>, <0x36010 0x4>; diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi index ce1194744f84..53d68786a61f 100644 --- a/arch/arm/boot/dts/dra7.dtsi +++ b/arch/arm/boot/dts/dra7.dtsi @@ -46,6 +46,7 @@ timer { compatible = "arm,armv7-timer"; + status = "disabled"; /* See ARM architected timer wrap erratum i940 */ interrupts = , , , @@ -1241,3 +1242,22 @@ assigned-clock-parents = <&sys_32k_ck>; }; }; + +/* Local timers, see ARM architected timer wrap erratum i940 */ +&timer3_target { + ti,no-reset-on-init; + ti,no-idle; + timer@0 { + assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER3_CLKCTRL 24>; + assigned-clock-parents = <&timer_sys_clk_div>; + }; +}; + +&timer4_target { + ti,no-reset-on-init; + ti,no-idle; + timer@0 { + assigned-clocks = <&l4per_clkctrl DRA7_L4PER_TIMER4_CLKCTRL 24>; + assigned-clock-parents = <&timer_sys_clk_div>; + }; +}; diff --git a/drivers/clocksource/timer-ti-dm-systimer.c b/drivers/clocksource/timer-ti-dm-systimer.c index 330803150d85..b6f97960d8ee 100644 --- a/drivers/clocksource/timer-ti-dm-systimer.c +++ b/drivers/clocksource/timer-ti-dm-systimer.c @@ -2,6 +2,7 @@ #include #include #include +#include #include #include #include @@ -630,6 +631,78 @@ err_out_free: return error; } +/* Dmtimer as percpu timer. See dra7 ARM architected timer wrap erratum i940 */ +static DEFINE_PER_CPU(struct dmtimer_clockevent, dmtimer_percpu_timer); + +static int __init dmtimer_percpu_timer_init(struct device_node *np, int cpu) +{ + struct dmtimer_clockevent *clkevt; + int error; + + if (!cpu_possible(cpu)) + return -EINVAL; + + if (!of_property_read_bool(np->parent, "ti,no-reset-on-init") || + !of_property_read_bool(np->parent, "ti,no-idle")) + pr_warn("Incomplete dtb for percpu dmtimer %pOF\n", np->parent); + + clkevt = per_cpu_ptr(&dmtimer_percpu_timer, cpu); + + error = dmtimer_clkevt_init_common(clkevt, np, CLOCK_EVT_FEAT_ONESHOT, + cpumask_of(cpu), "percpu-dmtimer", + 500); + if (error) + return error; + + return 0; +} + +/* See TRM for timer internal resynch latency */ +static int omap_dmtimer_starting_cpu(unsigned int cpu) +{ + struct dmtimer_clockevent *clkevt = per_cpu_ptr(&dmtimer_percpu_timer, cpu); + struct clock_event_device *dev = &clkevt->dev; + struct dmtimer_systimer *t = &clkevt->t; + + clockevents_config_and_register(dev, t->rate, 3, ULONG_MAX); + irq_force_affinity(dev->irq, cpumask_of(cpu)); + + return 0; +} + +static int __init dmtimer_percpu_timer_startup(void) +{ + struct dmtimer_clockevent *clkevt = per_cpu_ptr(&dmtimer_percpu_timer, 0); + struct dmtimer_systimer *t = &clkevt->t; + + if (t->sysc) { + cpuhp_setup_state(CPUHP_AP_TI_GP_TIMER_STARTING, + "clockevents/omap/gptimer:starting", + omap_dmtimer_starting_cpu, NULL); + } + + return 0; +} +subsys_initcall(dmtimer_percpu_timer_startup); + +static int __init dmtimer_percpu_quirk_init(struct device_node *np, u32 pa) +{ + struct device_node *arm_timer; + + arm_timer = of_find_compatible_node(NULL, NULL, "arm,armv7-timer"); + if (of_device_is_available(arm_timer)) { + pr_warn_once("ARM architected timer wrap issue i940 detected\n"); + return 0; + } + + if (pa == 0x48034000) /* dra7 dmtimer3 */ + return dmtimer_percpu_timer_init(np, 0); + else if (pa == 0x48036000) /* dra7 dmtimer4 */ + return dmtimer_percpu_timer_init(np, 1); + + return 0; +} + /* Clocksource */ static struct dmtimer_clocksource * to_dmtimer_clocksource(struct clocksource *cs) @@ -763,6 +836,9 @@ static int __init dmtimer_systimer_init(struct device_node *np) if (clockevent == pa) return dmtimer_clockevent_init(np); + if (of_machine_is_compatible("ti,dra7")) + return dmtimer_percpu_quirk_init(np, pa); + return 0; } diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index f14adb882338..cc7c3fda2aa6 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -135,6 +135,7 @@ enum cpuhp_state { CPUHP_AP_RISCV_TIMER_STARTING, CPUHP_AP_CLINT_TIMER_STARTING, CPUHP_AP_CSKY_TIMER_STARTING, + CPUHP_AP_TI_GP_TIMER_STARTING, CPUHP_AP_HYPERV_TIMER_STARTING, CPUHP_AP_KVM_STARTING, CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING, -- cgit v1.2.3 From 07ff4aed015c564d03fd518d2fb54e5e6948903c Mon Sep 17 00:00:00 2001 From: Marc Kleine-Budde Date: Wed, 3 Mar 2021 11:35:44 +0100 Subject: time/timecounter: Mark 1st argument of timecounter_cyc2time() as const The timecounter is not modified in this function. Mark it as const. Signed-off-by: Marc Kleine-Budde Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210303103544.994855-1-mkl@pengutronix.de --- include/linux/timecounter.h | 2 +- kernel/time/timecounter.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/timecounter.h b/include/linux/timecounter.h index 754b74a2167f..c6540ceea143 100644 --- a/include/linux/timecounter.h +++ b/include/linux/timecounter.h @@ -124,7 +124,7 @@ extern u64 timecounter_read(struct timecounter *tc); * This allows conversion of cycle counter values which were generated * in the past. */ -extern u64 timecounter_cyc2time(struct timecounter *tc, +extern u64 timecounter_cyc2time(const struct timecounter *tc, u64 cycle_tstamp); #endif diff --git a/kernel/time/timecounter.c b/kernel/time/timecounter.c index 85b98e727306..e6285288d765 100644 --- a/kernel/time/timecounter.c +++ b/kernel/time/timecounter.c @@ -76,7 +76,7 @@ static u64 cc_cyc2ns_backwards(const struct cyclecounter *cc, return ns; } -u64 timecounter_cyc2time(struct timecounter *tc, +u64 timecounter_cyc2time(const struct timecounter *tc, u64 cycle_tstamp) { u64 delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask; -- cgit v1.2.3