diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 685645e75706..4955d2faf4cc 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -612,8 +612,8 @@ clocksource.max_cswd_read_retries= [KNL] Number of clocksource_watchdog() retries due to external delays before the clock will be marked - unstable. Defaults to three retries, that is, - four attempts to read the clock under test. + unstable. Defaults to two retries, that is, + three attempts to read the clock under test. clocksource.verify_n_cpus= [KNL] Limit the number of CPUs checked for clocksources diff --git a/Documentation/devicetree/bindings/timer/cdns,ttc.yaml b/Documentation/devicetree/bindings/timer/cdns,ttc.yaml index 8615353f69b4..c3386076a98c 100644 --- a/Documentation/devicetree/bindings/timer/cdns,ttc.yaml +++ b/Documentation/devicetree/bindings/timer/cdns,ttc.yaml @@ -25,6 +25,9 @@ properties: clocks: maxItems: 1 + power-domains: + maxItems: 1 + timer-width: $ref: "/schemas/types.yaml#/definitions/uint32" description: | diff --git a/Documentation/devicetree/bindings/timer/mstar,msc313e-timer.yaml b/Documentation/devicetree/bindings/timer/mstar,msc313e-timer.yaml new file mode 100644 index 000000000000..03d5dba5d5b3 --- /dev/null +++ b/Documentation/devicetree/bindings/timer/mstar,msc313e-timer.yaml @@ -0,0 +1,46 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/timer/mstar,msc313e-timer.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Mstar MSC313e Timer Device Tree Bindings + +maintainers: + - Daniel Palmer + - Romain Perier + +properties: + compatible: + enum: + - mstar,msc313e-timer + - sstar,ssd20xd-timer + + reg: + maxItems: 1 + + interrupts: + maxItems: 1 + + clocks: + maxItems: 1 + +required: + - compatible + - reg + - interrupts + - clocks + +additionalProperties: false + +examples: + - | + #include + + timer@6040 { + compatible = "mstar,msc313e-timer"; + reg = <0x6040 0x40>; + clocks = <&xtal_div2>; + interrupts-extended = <&intc_fiq GIC_SPI 0 IRQ_TYPE_LEVEL_HIGH>; + }; +... diff --git a/Documentation/devicetree/bindings/timer/nxp,tpm-timer.yaml b/Documentation/devicetree/bindings/timer/nxp,tpm-timer.yaml index edd9585f6726..f69773a8e4b9 100644 --- a/Documentation/devicetree/bindings/timer/nxp,tpm-timer.yaml +++ b/Documentation/devicetree/bindings/timer/nxp,tpm-timer.yaml @@ -19,7 +19,11 @@ description: | properties: compatible: - const: fsl,imx7ulp-tpm + oneOf: + - const: fsl,imx7ulp-tpm + - items: + - const: fsl,imx8ulp-tpm + - const: fsl,imx7ulp-tpm reg: maxItems: 1 diff --git a/Documentation/devicetree/bindings/timer/renesas,ostm.yaml b/Documentation/devicetree/bindings/timer/renesas,ostm.yaml index 600d47ab7d58..7fa7f977b44c 100644 --- a/Documentation/devicetree/bindings/timer/renesas,ostm.yaml +++ b/Documentation/devicetree/bindings/timer/renesas,ostm.yaml @@ -21,9 +21,10 @@ properties: compatible: items: - enum: - - renesas,r7s72100-ostm # RZ/A1H - - renesas,r7s9210-ostm # RZ/A2M - - const: renesas,ostm # Generic + - renesas,r7s72100-ostm # RZ/A1H + - renesas,r7s9210-ostm # RZ/A2M + - renesas,r9a07g044-ostm # RZ/G2{L,LC} + - const: renesas,ostm # Generic reg: maxItems: 1 @@ -37,6 +38,9 @@ properties: power-domains: maxItems: 1 + resets: + maxItems: 1 + required: - compatible - reg @@ -44,6 +48,16 @@ required: - clocks - power-domains +if: + properties: + compatible: + contains: + enum: + - renesas,r9a07g044-ostm +then: + required: + - resets + additionalProperties: false examples: diff --git a/Documentation/devicetree/bindings/timer/rockchip,rk-timer.yaml b/Documentation/devicetree/bindings/timer/rockchip,rk-timer.yaml index e26ecb5893ae..5d157d87dad5 100644 --- a/Documentation/devicetree/bindings/timer/rockchip,rk-timer.yaml +++ b/Documentation/devicetree/bindings/timer/rockchip,rk-timer.yaml @@ -18,7 +18,6 @@ properties: - enum: - rockchip,rv1108-timer - rockchip,rk3036-timer - - rockchip,rk3066-timer - rockchip,rk3188-timer - rockchip,rk3228-timer - rockchip,rk3229-timer diff --git a/MAINTAINERS b/MAINTAINERS index e4cecccbd439..dc4a1370ef1b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2304,6 +2304,7 @@ F: Documentation/devicetree/bindings/gpio/mstar,msc313-gpio.yaml F: arch/arm/boot/dts/mstar-* F: arch/arm/mach-mstar/ F: drivers/clk/mstar/ +F: drivers/clocksource/timer-msc313e.c F: drivers/gpio/gpio-msc313.c F: drivers/rtc/rtc-msc313.c F: drivers/watchdog/msc313e_wdt.c diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig index f65e31bab9ae..cfb8ea0df3b1 100644 --- a/drivers/clocksource/Kconfig +++ b/drivers/clocksource/Kconfig @@ -510,7 +510,8 @@ config SH_TIMER_MTU2 This hardware comes with 16-bit timer registers. config RENESAS_OSTM - bool "Renesas OSTM timer driver" if COMPILE_TEST + bool "Renesas OSTM timer driver" + depends on ARCH_RENESAS || COMPILE_TEST select CLKSRC_MMIO select TIMER_OF help @@ -671,6 +672,15 @@ config MILBEAUT_TIMER help Enables the support for Milbeaut timer driver. +config MSC313E_TIMER + bool "MSC313E timer driver" if COMPILE_TEST + select TIMER_OF + select CLKSRC_MMIO + help + Enables support for the MStar MSC313E timer driver. + This provides access to multiple interrupt generating + programmable 32-bit free running incrementing counters. + config INGENIC_TIMER bool "Clocksource/timer using the TCU in Ingenic JZ SoCs" default MACH_INGENIC diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index c17ee32a7151..fa5f624eadb6 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -88,3 +88,4 @@ obj-$(CONFIG_CSKY_MP_TIMER) += timer-mp-csky.o obj-$(CONFIG_GX6605S_TIMER) += timer-gx6605s.o obj-$(CONFIG_HYPERV_TIMER) += hyperv_timer.o obj-$(CONFIG_MICROCHIP_PIT64B) += timer-microchip-pit64b.o +obj-$(CONFIG_MSC313E_TIMER) += timer-msc313e.o diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index 5e3e96d3d1b9..6db3d5511b0f 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -467,7 +467,7 @@ static int exynos4_mct_starting_cpu(unsigned int cpu) evt->tick_resume = set_state_shutdown; evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERCPU; - evt->rating = MCT_CLKEVENTS_RATING, + evt->rating = MCT_CLKEVENTS_RATING; exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET); @@ -504,11 +504,14 @@ static int exynos4_mct_dying_cpu(unsigned int cpu) return 0; } -static int __init exynos4_timer_resources(struct device_node *np, void __iomem *base) +static int __init exynos4_timer_resources(struct device_node *np) { - int err, cpu; struct clk *mct_clk, *tick_clk; + reg_base = of_iomap(np, 0); + if (!reg_base) + panic("%s: unable to ioremap mct address space\n", __func__); + tick_clk = of_clk_get_by_name(np, "fin_pll"); if (IS_ERR(tick_clk)) panic("%s: unable to determine tick clock rate\n", __func__); @@ -519,9 +522,27 @@ static int __init exynos4_timer_resources(struct device_node *np, void __iomem * panic("%s: unable to retrieve mct clock instance\n", __func__); clk_prepare_enable(mct_clk); - reg_base = base; - if (!reg_base) - panic("%s: unable to ioremap mct address space\n", __func__); + return 0; +} + +static int __init exynos4_timer_interrupts(struct device_node *np, + unsigned int int_type) +{ + int nr_irqs, i, err, cpu; + + mct_int_type = int_type; + + /* This driver uses only one global timer interrupt */ + mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ); + + /* + * Find out the number of local irqs specified. The local + * timer irqs are specified after the four global timer + * irqs are specified. + */ + nr_irqs = of_irq_count(np); + for (i = MCT_L0_IRQ; i < nr_irqs; i++) + mct_irqs[i] = irq_of_parse_and_map(np, i); if (mct_int_type == MCT_INT_PPI) { @@ -581,24 +602,13 @@ static int __init exynos4_timer_resources(struct device_node *np, void __iomem * static int __init mct_init_dt(struct device_node *np, unsigned int int_type) { - u32 nr_irqs, i; int ret; - mct_int_type = int_type; + ret = exynos4_timer_resources(np); + if (ret) + return ret; - /* This driver uses only one global timer interrupt */ - mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ); - - /* - * Find out the number of local irqs specified. The local - * timer irqs are specified after the four global timer - * irqs are specified. - */ - nr_irqs = of_irq_count(np); - for (i = MCT_L0_IRQ; i < nr_irqs; i++) - mct_irqs[i] = irq_of_parse_and_map(np, i); - - ret = exynos4_timer_resources(np, of_iomap(np, 0)); + ret = exynos4_timer_interrupts(np, int_type); if (ret) return ret; diff --git a/drivers/clocksource/renesas-ostm.c b/drivers/clocksource/renesas-ostm.c index 3d06ba66008c..21d1392637b8 100644 --- a/drivers/clocksource/renesas-ostm.c +++ b/drivers/clocksource/renesas-ostm.c @@ -9,6 +9,8 @@ #include #include #include +#include +#include #include #include @@ -159,6 +161,7 @@ static int __init ostm_init_clkevt(struct timer_of *to) static int __init ostm_init(struct device_node *np) { + struct reset_control *rstc; struct timer_of *to; int ret; @@ -166,6 +169,14 @@ static int __init ostm_init(struct device_node *np) if (!to) return -ENOMEM; + rstc = of_reset_control_get_optional_exclusive(np, NULL); + if (IS_ERR(rstc)) { + ret = PTR_ERR(rstc); + goto err_free; + } + + reset_control_deassert(rstc); + to->flags = TIMER_OF_BASE | TIMER_OF_CLOCK; if (system_clock) { /* @@ -178,7 +189,7 @@ static int __init ostm_init(struct device_node *np) ret = timer_of_init(np, to); if (ret) - goto err_free; + goto err_reset; /* * First probed device will be used as system clocksource. Any @@ -203,9 +214,35 @@ static int __init ostm_init(struct device_node *np) err_cleanup: timer_of_cleanup(to); +err_reset: + reset_control_assert(rstc); + reset_control_put(rstc); err_free: kfree(to); return ret; } TIMER_OF_DECLARE(ostm, "renesas,ostm", ostm_init); + +#ifdef CONFIG_ARCH_R9A07G044 +static int __init ostm_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + + return ostm_init(dev->of_node); +} + +static const struct of_device_id ostm_of_table[] = { + { .compatible = "renesas,ostm", }, + { /* sentinel */ } +}; + +static struct platform_driver ostm_device_driver = { + .driver = { + .name = "renesas_ostm", + .of_match_table = of_match_ptr(ostm_of_table), + .suppress_bind_attrs = true, + }, +}; +builtin_platform_driver_probe(ostm_device_driver, ostm_probe); +#endif diff --git a/drivers/clocksource/timer-imx-sysctr.c b/drivers/clocksource/timer-imx-sysctr.c index 18b90fc56bfc..55a8e198d2a1 100644 --- a/drivers/clocksource/timer-imx-sysctr.c +++ b/drivers/clocksource/timer-imx-sysctr.c @@ -20,8 +20,8 @@ #define SYS_CTR_CLK_DIV 0x3 -static void __iomem *sys_ctr_base; -static u32 cmpcr; +static void __iomem *sys_ctr_base __ro_after_init; +static u32 cmpcr __ro_after_init; static void sysctr_timer_enable(bool enable) { @@ -119,7 +119,7 @@ static struct timer_of to_sysctr = { static void __init sysctr_clockevent_init(void) { - to_sysctr.clkevt.cpumask = cpumask_of(0); + to_sysctr.clkevt.cpumask = cpu_possible_mask; clockevents_config_and_register(&to_sysctr.clkevt, timer_of_rate(&to_sysctr), diff --git a/drivers/clocksource/timer-msc313e.c b/drivers/clocksource/timer-msc313e.c new file mode 100644 index 000000000000..54c54ca7c786 --- /dev/null +++ b/drivers/clocksource/timer-msc313e.c @@ -0,0 +1,253 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * MStar timer driver + * + * Copyright (C) 2021 Daniel Palmer + * Copyright (C) 2021 Romain Perier + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#ifdef CONFIG_ARM +#include +#endif + +#include "timer-of.h" + +#define TIMER_NAME "msc313e_timer" + +#define MSC313E_REG_CTRL 0x00 +#define MSC313E_REG_CTRL_TIMER_EN BIT(0) +#define MSC313E_REG_CTRL_TIMER_TRIG BIT(1) +#define MSC313E_REG_CTRL_TIMER_INT_EN BIT(8) +#define MSC313E_REG_TIMER_MAX_LOW 0x08 +#define MSC313E_REG_TIMER_MAX_HIGH 0x0c +#define MSC313E_REG_COUNTER_LOW 0x10 +#define MSC313E_REG_COUNTER_HIGH 0x14 +#define MSC313E_REG_TIMER_DIVIDE 0x18 + +#define MSC313E_CLK_DIVIDER 9 +#define TIMER_SYNC_TICKS 3 + +#ifdef CONFIG_ARM +struct msc313e_delay { + void __iomem *base; + struct delay_timer delay; +}; +static struct msc313e_delay msc313e_delay; +#endif + +static void __iomem *msc313e_clksrc; + +static void msc313e_timer_stop(void __iomem *base) +{ + writew(0, base + MSC313E_REG_CTRL); +} + +static void msc313e_timer_start(void __iomem *base, bool periodic) +{ + u16 reg; + + reg = readw(base + MSC313E_REG_CTRL); + if (periodic) + reg |= MSC313E_REG_CTRL_TIMER_EN; + else + reg |= MSC313E_REG_CTRL_TIMER_TRIG; + writew(reg | MSC313E_REG_CTRL_TIMER_INT_EN, base + MSC313E_REG_CTRL); +} + +static void msc313e_timer_setup(void __iomem *base, unsigned long delay) +{ + unsigned long flags; + + local_irq_save(flags); + writew(delay >> 16, base + MSC313E_REG_TIMER_MAX_HIGH); + writew(delay & 0xffff, base + MSC313E_REG_TIMER_MAX_LOW); + local_irq_restore(flags); +} + +static unsigned long msc313e_timer_current_value(void __iomem *base) +{ + unsigned long flags; + u16 l, h; + + local_irq_save(flags); + l = readw(base + MSC313E_REG_COUNTER_LOW); + h = readw(base + MSC313E_REG_COUNTER_HIGH); + local_irq_restore(flags); + + return (((u32)h) << 16 | l); +} + +static int msc313e_timer_clkevt_shutdown(struct clock_event_device *evt) +{ + struct timer_of *timer = to_timer_of(evt); + + msc313e_timer_stop(timer_of_base(timer)); + + return 0; +} + +static int msc313e_timer_clkevt_set_oneshot(struct clock_event_device *evt) +{ + struct timer_of *timer = to_timer_of(evt); + + msc313e_timer_stop(timer_of_base(timer)); + msc313e_timer_start(timer_of_base(timer), false); + + return 0; +} + +static int msc313e_timer_clkevt_set_periodic(struct clock_event_device *evt) +{ + struct timer_of *timer = to_timer_of(evt); + + msc313e_timer_stop(timer_of_base(timer)); + msc313e_timer_setup(timer_of_base(timer), timer_of_period(timer)); + msc313e_timer_start(timer_of_base(timer), true); + + return 0; +} + +static int msc313e_timer_clkevt_next_event(unsigned long evt, struct clock_event_device *clkevt) +{ + struct timer_of *timer = to_timer_of(clkevt); + + msc313e_timer_stop(timer_of_base(timer)); + msc313e_timer_setup(timer_of_base(timer), evt); + msc313e_timer_start(timer_of_base(timer), false); + + return 0; +} + +static irqreturn_t msc313e_timer_clkevt_irq(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static u64 msc313e_timer_clksrc_read(struct clocksource *cs) +{ + return msc313e_timer_current_value(msc313e_clksrc) & cs->mask; +} + +#ifdef CONFIG_ARM +static unsigned long msc313e_read_delay_timer_read(void) +{ + return msc313e_timer_current_value(msc313e_delay.base); +} +#endif + +static u64 msc313e_timer_sched_clock_read(void) +{ + return msc313e_timer_current_value(msc313e_clksrc); +} + +static struct clock_event_device msc313e_clkevt = { + .name = TIMER_NAME, + .rating = 300, + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .set_state_shutdown = msc313e_timer_clkevt_shutdown, + .set_state_periodic = msc313e_timer_clkevt_set_periodic, + .set_state_oneshot = msc313e_timer_clkevt_set_oneshot, + .tick_resume = msc313e_timer_clkevt_shutdown, + .set_next_event = msc313e_timer_clkevt_next_event, +}; + +static int __init msc313e_clkevt_init(struct device_node *np) +{ + int ret; + struct timer_of *to; + + to = kzalloc(sizeof(*to), GFP_KERNEL); + if (!to) + return -ENOMEM; + + to->flags = TIMER_OF_IRQ | TIMER_OF_CLOCK | TIMER_OF_BASE; + to->of_irq.handler = msc313e_timer_clkevt_irq; + ret = timer_of_init(np, to); + if (ret) + return ret; + + if (of_device_is_compatible(np, "sstar,ssd20xd-timer")) { + to->of_clk.rate = clk_get_rate(to->of_clk.clk) / MSC313E_CLK_DIVIDER; + to->of_clk.period = DIV_ROUND_UP(to->of_clk.rate, HZ); + writew(MSC313E_CLK_DIVIDER - 1, timer_of_base(to) + MSC313E_REG_TIMER_DIVIDE); + } + + msc313e_clkevt.cpumask = cpu_possible_mask; + msc313e_clkevt.irq = to->of_irq.irq; + to->clkevt = msc313e_clkevt; + + clockevents_config_and_register(&to->clkevt, timer_of_rate(to), + TIMER_SYNC_TICKS, 0xffffffff); + return 0; +} + +static int __init msc313e_clksrc_init(struct device_node *np) +{ + struct timer_of to = { 0 }; + int ret; + u16 reg; + + to.flags = TIMER_OF_BASE | TIMER_OF_CLOCK; + ret = timer_of_init(np, &to); + if (ret) + return ret; + + msc313e_clksrc = timer_of_base(&to); + reg = readw(msc313e_clksrc + MSC313E_REG_CTRL); + reg |= MSC313E_REG_CTRL_TIMER_EN; + writew(reg, msc313e_clksrc + MSC313E_REG_CTRL); + +#ifdef CONFIG_ARM + msc313e_delay.base = timer_of_base(&to); + msc313e_delay.delay.read_current_timer = msc313e_read_delay_timer_read; + msc313e_delay.delay.freq = timer_of_rate(&to); + + register_current_timer_delay(&msc313e_delay.delay); +#endif + + sched_clock_register(msc313e_timer_sched_clock_read, 32, timer_of_rate(&to)); + return clocksource_mmio_init(timer_of_base(&to), TIMER_NAME, timer_of_rate(&to), 300, 32, + msc313e_timer_clksrc_read); +} + +static int __init msc313e_timer_init(struct device_node *np) +{ + int ret = 0; + static int num_called; + + switch (num_called) { + case 0: + ret = msc313e_clksrc_init(np); + if (ret) + return ret; + break; + + default: + ret = msc313e_clkevt_init(np); + if (ret) + return ret; + break; + } + + num_called++; + + return 0; +} + +TIMER_OF_DECLARE(msc313, "mstar,msc313e-timer", msc313e_timer_init); +TIMER_OF_DECLARE(ssd20xd, "sstar,ssd20xd-timer", msc313e_timer_init); diff --git a/drivers/clocksource/timer-pistachio.c b/drivers/clocksource/timer-pistachio.c index 6f37181a8c63..69c069e6f0a2 100644 --- a/drivers/clocksource/timer-pistachio.c +++ b/drivers/clocksource/timer-pistachio.c @@ -71,7 +71,8 @@ static u64 notrace pistachio_clocksource_read_cycles(struct clocksource *cs) { struct pistachio_clocksource *pcs = to_pistachio_clocksource(cs); - u32 counter, overflow; + __maybe_unused u32 overflow; + u32 counter; unsigned long flags; /* diff --git a/include/linux/reset.h b/include/linux/reset.h index db0e6115a2f6..8a21b5756c3e 100644 --- a/include/linux/reset.h +++ b/include/linux/reset.h @@ -454,6 +454,26 @@ static inline struct reset_control *of_reset_control_get_exclusive( return __of_reset_control_get(node, id, 0, false, false, true); } +/** + * of_reset_control_get_optional_exclusive - Lookup and obtain an optional exclusive + * reference to a reset controller. + * @node: device to be reset by the controller + * @id: reset line name + * + * Optional variant of of_reset_control_get_exclusive(). If the requested reset + * is not specified in the device tree, this function returns NULL instead of + * an error. + * + * Returns a struct reset_control or IS_ERR() condition containing errno. + * + * Use of id names is optional. + */ +static inline struct reset_control *of_reset_control_get_optional_exclusive( + struct device_node *node, const char *id) +{ + return __of_reset_control_get(node, id, 0, false, true, true); +} + /** * of_reset_control_get_shared - Lookup and obtain a shared reference * to a reset controller. diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index b8a14d2fb5ba..b7e52a642948 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -107,7 +107,7 @@ static u64 suspend_start; * This delay could be due to SMIs, NMIs, or to VCPU preemptions. Used as * a lower bound for cs->uncertainty_margin values when registering clocks. */ -#define WATCHDOG_MAX_SKEW (50 * NSEC_PER_USEC) +#define WATCHDOG_MAX_SKEW (100 * NSEC_PER_USEC) #ifdef CONFIG_CLOCKSOURCE_WATCHDOG static void clocksource_watchdog_work(struct work_struct *work); @@ -199,23 +199,30 @@ void clocksource_mark_unstable(struct clocksource *cs) spin_unlock_irqrestore(&watchdog_lock, flags); } -ulong max_cswd_read_retries = 3; +ulong max_cswd_read_retries = 2; module_param(max_cswd_read_retries, ulong, 0644); EXPORT_SYMBOL_GPL(max_cswd_read_retries); static int verify_n_cpus = 8; module_param(verify_n_cpus, int, 0644); -static bool cs_watchdog_read(struct clocksource *cs, u64 *csnow, u64 *wdnow) +enum wd_read_status { + WD_READ_SUCCESS, + WD_READ_UNSTABLE, + WD_READ_SKIP +}; + +static enum wd_read_status cs_watchdog_read(struct clocksource *cs, u64 *csnow, u64 *wdnow) { unsigned int nretries; - u64 wd_end, wd_delta; - int64_t wd_delay; + u64 wd_end, wd_end2, wd_delta; + int64_t wd_delay, wd_seq_delay; for (nretries = 0; nretries <= max_cswd_read_retries; nretries++) { local_irq_disable(); *wdnow = watchdog->read(watchdog); *csnow = cs->read(cs); wd_end = watchdog->read(watchdog); + wd_end2 = watchdog->read(watchdog); local_irq_enable(); wd_delta = clocksource_delta(wd_end, *wdnow, watchdog->mask); @@ -226,13 +233,34 @@ static bool cs_watchdog_read(struct clocksource *cs, u64 *csnow, u64 *wdnow) pr_warn("timekeeping watchdog on CPU%d: %s retried %d times before success\n", smp_processor_id(), watchdog->name, nretries); } - return true; + return WD_READ_SUCCESS; } + + /* + * Now compute delay in consecutive watchdog read to see if + * there is too much external interferences that cause + * significant delay in reading both clocksource and watchdog. + * + * If consecutive WD read-back delay > WATCHDOG_MAX_SKEW/2, + * report system busy, reinit the watchdog and skip the current + * watchdog test. + */ + wd_delta = clocksource_delta(wd_end2, wd_end, watchdog->mask); + wd_seq_delay = clocksource_cyc2ns(wd_delta, watchdog->mult, watchdog->shift); + if (wd_seq_delay > WATCHDOG_MAX_SKEW/2) + goto skip_test; } pr_warn("timekeeping watchdog on CPU%d: %s read-back delay of %lldns, attempt %d, marking unstable\n", smp_processor_id(), watchdog->name, wd_delay, nretries); - return false; + return WD_READ_UNSTABLE; + +skip_test: + pr_info("timekeeping watchdog on CPU%d: %s wd-wd read-back delay of %lldns\n", + smp_processor_id(), watchdog->name, wd_seq_delay); + pr_info("wd-%s-wd read-back delay of %lldns, clock-skew test skipped!\n", + cs->name, wd_delay); + return WD_READ_SKIP; } static u64 csnow_mid; @@ -356,6 +384,7 @@ static void clocksource_watchdog(struct timer_list *unused) int next_cpu, reset_pending; int64_t wd_nsec, cs_nsec; struct clocksource *cs; + enum wd_read_status read_ret; u32 md; spin_lock(&watchdog_lock); @@ -373,9 +402,12 @@ static void clocksource_watchdog(struct timer_list *unused) continue; } - if (!cs_watchdog_read(cs, &csnow, &wdnow)) { - /* Clock readout unreliable, so give it up. */ - __clocksource_unstable(cs); + read_ret = cs_watchdog_read(cs, &csnow, &wdnow); + + if (read_ret != WD_READ_SUCCESS) { + if (read_ret == WD_READ_UNSTABLE) + /* Clock readout unreliable, so give it up. */ + __clocksource_unstable(cs); continue; }