* [Backport for linux-5.10.y PATCH 1/2] clocksource/drivers/timer-ti-dm: Prepare to handle dra7 timer wrap issue @ 2021-05-17 8:22 Tony Lindgren 2021-05-17 8:22 ` [Backport for linux-5.10.y PATCH 2/2] clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 Tony Lindgren 0 siblings, 1 reply; 4+ messages in thread From: Tony Lindgren @ 2021-05-17 8:22 UTC (permalink / raw) To: stable; +Cc: linux-kernel, linux-omap, Daniel Lezcano Upstream commit 3efe7a878a11c13b5297057bfc1e5639ce1241ce. Updated to apply to stable linux-5.10.y without need for upstream typo fix commit 4bf07f6562a01a488877e05267808da7147f44a5. Needed to avoid duplicate code for upstream commit 25de4ce5ed02994aea8bc111d133308f6fd62566. 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 timers instead. Let's prepare for adding support for percpu timers by adding a common dmtimer_clkevt_init_common() and call it from dmtimer_clockevent_init(). This patch makes no intentional functional changes. Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20210323074326.28302-2-tony@atomide.com --- drivers/clocksource/timer-ti-dm-systimer.c | 68 ++++++++++++++-------- 1 file changed, 44 insertions(+), 24 deletions(-) diff --git a/drivers/clocksource/timer-ti-dm-systimer.c b/drivers/clocksource/timer-ti-dm-systimer.c --- a/drivers/clocksource/timer-ti-dm-systimer.c +++ b/drivers/clocksource/timer-ti-dm-systimer.c @@ -530,17 +530,17 @@ static void omap_clockevent_unidle(struct clock_event_device *evt) writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup); } -static int __init dmtimer_clockevent_init(struct device_node *np) +static int __init dmtimer_clkevt_init_common(struct dmtimer_clockevent *clkevt, + struct device_node *np, + unsigned int features, + const struct cpumask *cpumask, + const char *name, + int rating) { - struct dmtimer_clockevent *clkevt; struct clock_event_device *dev; struct dmtimer_systimer *t; int error; - clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL); - if (!clkevt) - return -ENOMEM; - t = &clkevt->t; dev = &clkevt->dev; @@ -548,25 +548,23 @@ static int __init dmtimer_clockevent_init(struct device_node *np) * We mostly use cpuidle_coupled with ARM local timers for runtime, * so there's probably no use for CLOCK_EVT_FEAT_DYNIRQ here. */ - dev->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT; - dev->rating = 300; + dev->features = features; + dev->rating = rating; dev->set_next_event = dmtimer_set_next_event; dev->set_state_shutdown = dmtimer_clockevent_shutdown; dev->set_state_periodic = dmtimer_set_periodic; dev->set_state_oneshot = dmtimer_clockevent_shutdown; dev->set_state_oneshot_stopped = dmtimer_clockevent_shutdown; dev->tick_resume = dmtimer_clockevent_shutdown; - dev->cpumask = cpu_possible_mask; + dev->cpumask = cpumask; dev->irq = irq_of_parse_and_map(np, 0); - if (!dev->irq) { - error = -ENXIO; - goto err_out_free; - } + if (!dev->irq) + return -ENXIO; error = dmtimer_systimer_setup(np, &clkevt->t); if (error) - goto err_out_free; + return error; clkevt->period = 0xffffffff - DIV_ROUND_CLOSEST(t->rate, HZ); @@ -578,32 +576,54 @@ static int __init dmtimer_clockevent_init(struct device_node *np) writel_relaxed(OMAP_TIMER_CTRL_POSTED, t->base + t->ifctrl); error = request_irq(dev->irq, dmtimer_clockevent_interrupt, - IRQF_TIMER, "clockevent", clkevt); + IRQF_TIMER, name, clkevt); if (error) goto err_out_unmap; writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena); writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup); - pr_info("TI gptimer clockevent: %s%lu Hz at %pOF\n", - of_find_property(np, "ti,timer-alwon", NULL) ? + pr_info("TI gptimer %s: %s%lu Hz at %pOF\n", + name, of_find_property(np, "ti,timer-alwon", NULL) ? "always-on " : "", t->rate, np->parent); - clockevents_config_and_register(dev, t->rate, - 3, /* Timer internal resynch latency */ + return 0; + +err_out_unmap: + iounmap(t->base); + + return error; +} + +static int __init dmtimer_clockevent_init(struct device_node *np) +{ + struct dmtimer_clockevent *clkevt; + int error; + + clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL); + if (!clkevt) + return -ENOMEM; + + error = dmtimer_clkevt_init_common(clkevt, np, + CLOCK_EVT_FEAT_PERIODIC | + CLOCK_EVT_FEAT_ONESHOT, + cpu_possible_mask, "clockevent", + 300); + if (error) + goto err_out_free; + + clockevents_config_and_register(&clkevt->dev, clkevt->t.rate, + 3, /* Timer internal resync latency */ 0xffffffff); if (of_machine_is_compatible("ti,am33xx") || of_machine_is_compatible("ti,am43")) { - dev->suspend = omap_clockevent_idle; - dev->resume = omap_clockevent_unidle; + clkevt->dev.suspend = omap_clockevent_idle; + clkevt->dev.resume = omap_clockevent_unidle; } return 0; -err_out_unmap: - iounmap(t->base); - err_out_free: kfree(clkevt); -- 2.31.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Backport for linux-5.10.y PATCH 2/2] clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 2021-05-17 8:22 [Backport for linux-5.10.y PATCH 1/2] clocksource/drivers/timer-ti-dm: Prepare to handle dra7 timer wrap issue Tony Lindgren @ 2021-05-17 8:22 ` Tony Lindgren 2021-05-17 8:42 ` Tony Lindgren 0 siblings, 1 reply; 4+ messages in thread From: Tony Lindgren @ 2021-05-17 8:22 UTC (permalink / raw) To: stable; +Cc: linux-kernel, linux-omap, Keerthy, Tero Kristo, Daniel Lezcano Upstream commit 25de4ce5ed02994aea8bc111d133308f6fd62566 for stable linux-5.10.y. Depends on backported upstream commit 3efe7a878a11c13b5297057bfc1e5639ce1241ce. 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 <j-keerthy@ti.com> Cc: Tero Kristo <kristo@kernel.org> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> 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(-) diff --git a/arch/arm/boot/dts/dra7-l4.dtsi b/arch/arm/boot/dts/dra7-l4.dtsi --- a/arch/arm/boot/dts/dra7-l4.dtsi +++ b/arch/arm/boot/dts/dra7-l4.dtsi @@ -1168,7 +1168,7 @@ timer2: timer@0 { }; }; - 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 @@ timer3: timer@0 { }; }; - 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 --- a/arch/arm/boot/dts/dra7.dtsi +++ b/arch/arm/boot/dts/dra7.dtsi @@ -46,6 +46,7 @@ aliases { timer { compatible = "arm,armv7-timer"; + status = "disabled"; /* See ARM architected timer wrap erratum i940 */ interrupts = <GIC_PPI 13 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>, <GIC_PPI 14 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>, <GIC_PPI 11 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_LEVEL_LOW)>, @@ -1090,3 +1091,22 @@ timer@0 { 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 --- a/drivers/clocksource/timer-ti-dm-systimer.c +++ b/drivers/clocksource/timer-ti-dm-systimer.c @@ -2,6 +2,7 @@ #include <linux/clk.h> #include <linux/clocksource.h> #include <linux/clockchips.h> +#include <linux/cpuhotplug.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/iopoll.h> @@ -630,6 +631,78 @@ static int __init dmtimer_clockevent_init(struct device_node *np) 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 --- 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, -- 2.31.1 ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Backport for linux-5.10.y PATCH 2/2] clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 2021-05-17 8:22 ` [Backport for linux-5.10.y PATCH 2/2] clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 Tony Lindgren @ 2021-05-17 8:42 ` Tony Lindgren 2021-05-17 10:32 ` Greg KH 0 siblings, 1 reply; 4+ messages in thread From: Tony Lindgren @ 2021-05-17 8:42 UTC (permalink / raw) To: stable; +Cc: linux-kernel, linux-omap, Keerthy, Tero Kristo, Daniel Lezcano * Tony Lindgren <tony@atomide.com> [210517 08:23]: > Upstream commit 25de4ce5ed02994aea8bc111d133308f6fd62566 for stable > linux-5.10.y. Depends on backported upstream commit > 3efe7a878a11c13b5297057bfc1e5639ce1241ce. > > 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. FYI, these patches also apply to linux-5.11.y and linux-5.12.y. This patch applies with fuzz to the related device tree changes though, so please let me know if separate patches are needed. Regards, Tony ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Backport for linux-5.10.y PATCH 2/2] clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 2021-05-17 8:42 ` Tony Lindgren @ 2021-05-17 10:32 ` Greg KH 0 siblings, 0 replies; 4+ messages in thread From: Greg KH @ 2021-05-17 10:32 UTC (permalink / raw) To: Tony Lindgren Cc: stable, linux-kernel, linux-omap, Keerthy, Tero Kristo, Daniel Lezcano On Mon, May 17, 2021 at 11:42:26AM +0300, Tony Lindgren wrote: > * Tony Lindgren <tony@atomide.com> [210517 08:23]: > > Upstream commit 25de4ce5ed02994aea8bc111d133308f6fd62566 for stable > > linux-5.10.y. Depends on backported upstream commit > > 3efe7a878a11c13b5297057bfc1e5639ce1241ce. > > > > 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. > > FYI, these patches also apply to linux-5.11.y and linux-5.12.y. This > patch applies with fuzz to the related device tree changes though, > so please let me know if separate patches are needed. All now queued up, thanks. greg k-h ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-05-17 10:32 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-05-17 8:22 [Backport for linux-5.10.y PATCH 1/2] clocksource/drivers/timer-ti-dm: Prepare to handle dra7 timer wrap issue Tony Lindgren 2021-05-17 8:22 ` [Backport for linux-5.10.y PATCH 2/2] clocksource/drivers/timer-ti-dm: Handle dra7 timer wrap errata i940 Tony Lindgren 2021-05-17 8:42 ` Tony Lindgren 2021-05-17 10:32 ` Greg KH
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