From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug alb_break_llc() decides whether to break LLC preference during active load balance. It does so by testing that every runnable fair task on the source rq prefers its LLC: env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable But the two counters cover different sets. nr_pref_llc_running is updated in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued, so it follows queued tasks. h_nr_runnable is updated in set_delayed()/ clear_delayed() and drops delay-dequeued tasks. So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks, alb_break_llc() returns false, and active balance is free to pull a task off its preferred LLC. Active balance only moves runnable tasks, and this is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB skips the per-task test in can_migrate_task(). The runnable set is the one we want. Fix it on the counter side. A task should be counted in nr_pref_llc_running exactly while it is both queued on its preferred LLC (pref_llc_queued) and runnable (!sched_delayed). Define that membership once in task_pref_llc_runnable(), and adjust the counter only through pref_llc_running_inc()/pref_llc_running_dec() from the four sites that change either input: account_llc_enqueue(), account_llc_dequeue(), set_delayed() and clear_delayed(). Gating every update on the same predicate keeps the delay, wake and dequeue paths from double-counting or underflowing; see the comments at those sites for the ordering. nr_llc_running and sd->llc_counts are not touched and stay on queued semantics. Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC") Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/ Reported-by: Zhan Xusheng Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- drivers/rtc/rtc-da9055.c | 399 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 399 insertions(+) create mode 100644 drivers/rtc/rtc-da9055.c (limited to 'drivers/rtc/rtc-da9055.c') diff --git a/drivers/rtc/rtc-da9055.c b/drivers/rtc/rtc-da9055.c new file mode 100644 index 000000000..05adec6b7 --- /dev/null +++ b/drivers/rtc/rtc-da9055.c @@ -0,0 +1,399 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Real time clock driver for DA9055 + * + * Copyright(c) 2012 Dialog Semiconductor Ltd. + * + * Author: Dajun Dajun Chen + */ + +#include +#include +#include + +#include +#include +#include + +struct da9055_rtc { + struct rtc_device *rtc; + struct da9055 *da9055; + int alarm_enable; +}; + +static int da9055_rtc_enable_alarm(struct da9055_rtc *rtc, bool enable) +{ + int ret; + if (enable) { + ret = da9055_reg_update(rtc->da9055, DA9055_REG_ALARM_Y, + DA9055_RTC_ALM_EN, + DA9055_RTC_ALM_EN); + if (ret != 0) + dev_err(rtc->da9055->dev, "Failed to enable ALM: %d\n", + ret); + rtc->alarm_enable = 1; + } else { + ret = da9055_reg_update(rtc->da9055, DA9055_REG_ALARM_Y, + DA9055_RTC_ALM_EN, 0); + if (ret != 0) + dev_err(rtc->da9055->dev, + "Failed to disable ALM: %d\n", ret); + rtc->alarm_enable = 0; + } + return ret; +} + +static irqreturn_t da9055_rtc_alm_irq(int irq, void *data) +{ + struct da9055_rtc *rtc = data; + + da9055_rtc_enable_alarm(rtc, 0); + rtc_update_irq(rtc->rtc, 1, RTC_IRQF | RTC_AF); + + return IRQ_HANDLED; +} + +static int da9055_read_alarm(struct da9055 *da9055, struct rtc_time *rtc_tm) +{ + int ret; + uint8_t v[5]; + + ret = da9055_group_read(da9055, DA9055_REG_ALARM_MI, 5, v); + if (ret != 0) { + dev_err(da9055->dev, "Failed to group read ALM: %d\n", ret); + return ret; + } + + rtc_tm->tm_year = (v[4] & DA9055_RTC_ALM_YEAR) + 100; + rtc_tm->tm_mon = (v[3] & DA9055_RTC_ALM_MONTH) - 1; + rtc_tm->tm_mday = v[2] & DA9055_RTC_ALM_DAY; + rtc_tm->tm_hour = v[1] & DA9055_RTC_ALM_HOUR; + rtc_tm->tm_min = v[0] & DA9055_RTC_ALM_MIN; + rtc_tm->tm_sec = 0; + + return rtc_valid_tm(rtc_tm); +} + +static int da9055_set_alarm(struct da9055 *da9055, struct rtc_time *rtc_tm) +{ + int ret; + uint8_t v[2]; + + rtc_tm->tm_year -= 100; + rtc_tm->tm_mon += 1; + + ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MI, + DA9055_RTC_ALM_MIN, rtc_tm->tm_min); + if (ret != 0) { + dev_err(da9055->dev, "Failed to write ALRM MIN: %d\n", ret); + return ret; + } + + v[0] = rtc_tm->tm_hour; + v[1] = rtc_tm->tm_mday; + + ret = da9055_group_write(da9055, DA9055_REG_ALARM_H, 2, v); + if (ret < 0) + return ret; + + ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MO, + DA9055_RTC_ALM_MONTH, rtc_tm->tm_mon); + if (ret < 0) + dev_err(da9055->dev, "Failed to write ALM Month:%d\n", ret); + + ret = da9055_reg_update(da9055, DA9055_REG_ALARM_Y, + DA9055_RTC_ALM_YEAR, rtc_tm->tm_year); + if (ret < 0) + dev_err(da9055->dev, "Failed to write ALM Year:%d\n", ret); + + return ret; +} + +static int da9055_rtc_get_alarm_status(struct da9055 *da9055) +{ + int ret; + + ret = da9055_reg_read(da9055, DA9055_REG_ALARM_Y); + if (ret < 0) { + dev_err(da9055->dev, "Failed to read ALM: %d\n", ret); + return ret; + } + ret &= DA9055_RTC_ALM_EN; + return (ret > 0) ? 1 : 0; +} + +static int da9055_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm) +{ + struct da9055_rtc *rtc = dev_get_drvdata(dev); + uint8_t v[6]; + int ret; + + ret = da9055_reg_read(rtc->da9055, DA9055_REG_COUNT_S); + if (ret < 0) + return ret; + + /* + * Registers are only valid when RTC_READ + * status bit is asserted + */ + if (!(ret & DA9055_RTC_READ)) + return -EBUSY; + + ret = da9055_group_read(rtc->da9055, DA9055_REG_COUNT_S, 6, v); + if (ret < 0) { + dev_err(rtc->da9055->dev, "Failed to read RTC time : %d\n", + ret); + return ret; + } + + rtc_tm->tm_year = (v[5] & DA9055_RTC_YEAR) + 100; + rtc_tm->tm_mon = (v[4] & DA9055_RTC_MONTH) - 1; + rtc_tm->tm_mday = v[3] & DA9055_RTC_DAY; + rtc_tm->tm_hour = v[2] & DA9055_RTC_HOUR; + rtc_tm->tm_min = v[1] & DA9055_RTC_MIN; + rtc_tm->tm_sec = v[0] & DA9055_RTC_SEC; + + return 0; +} + +static int da9055_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct da9055_rtc *rtc; + uint8_t v[6]; + + rtc = dev_get_drvdata(dev); + + v[0] = tm->tm_sec; + v[1] = tm->tm_min; + v[2] = tm->tm_hour; + v[3] = tm->tm_mday; + v[4] = tm->tm_mon + 1; + v[5] = tm->tm_year - 100; + + return da9055_group_write(rtc->da9055, DA9055_REG_COUNT_S, 6, v); +} + +static int da9055_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + int ret; + struct rtc_time *tm = &alrm->time; + struct da9055_rtc *rtc = dev_get_drvdata(dev); + + ret = da9055_read_alarm(rtc->da9055, tm); + + if (ret) + return ret; + + alrm->enabled = da9055_rtc_get_alarm_status(rtc->da9055); + + return 0; +} + +static int da9055_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + int ret; + struct rtc_time *tm = &alrm->time; + struct da9055_rtc *rtc = dev_get_drvdata(dev); + + ret = da9055_rtc_enable_alarm(rtc, 0); + if (ret < 0) + return ret; + + ret = da9055_set_alarm(rtc->da9055, tm); + if (ret) + return ret; + + ret = da9055_rtc_enable_alarm(rtc, 1); + + return ret; +} + +static int da9055_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct da9055_rtc *rtc = dev_get_drvdata(dev); + + return da9055_rtc_enable_alarm(rtc, enabled); +} + +static const struct rtc_class_ops da9055_rtc_ops = { + .read_time = da9055_rtc_read_time, + .set_time = da9055_rtc_set_time, + .read_alarm = da9055_rtc_read_alarm, + .set_alarm = da9055_rtc_set_alarm, + .alarm_irq_enable = da9055_rtc_alarm_irq_enable, +}; + +static int da9055_rtc_device_init(struct da9055 *da9055, + struct da9055_pdata *pdata) +{ + int ret; + + /* Enable RTC and the internal Crystal */ + ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B, + DA9055_RTC_EN, DA9055_RTC_EN); + if (ret < 0) + return ret; + ret = da9055_reg_update(da9055, DA9055_REG_EN_32K, + DA9055_CRYSTAL_EN, DA9055_CRYSTAL_EN); + if (ret < 0) + return ret; + + /* Enable RTC in Power Down mode */ + ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B, + DA9055_RTC_MODE_PD, DA9055_RTC_MODE_PD); + if (ret < 0) + return ret; + + /* Enable RTC in Reset mode */ + if (pdata && pdata->reset_enable) { + ret = da9055_reg_update(da9055, DA9055_REG_CONTROL_B, + DA9055_RTC_MODE_SD, + DA9055_RTC_MODE_SD << + DA9055_RTC_MODE_SD_SHIFT); + if (ret < 0) + return ret; + } + + /* Disable the RTC TICK ALM */ + ret = da9055_reg_update(da9055, DA9055_REG_ALARM_MO, + DA9055_RTC_TICK_WAKE_MASK, 0); + if (ret < 0) + return ret; + + return 0; +} + +static int da9055_rtc_probe(struct platform_device *pdev) +{ + struct da9055_rtc *rtc; + struct da9055_pdata *pdata = NULL; + int ret, alm_irq; + + rtc = devm_kzalloc(&pdev->dev, sizeof(struct da9055_rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + rtc->da9055 = dev_get_drvdata(pdev->dev.parent); + pdata = dev_get_platdata(rtc->da9055->dev); + platform_set_drvdata(pdev, rtc); + + ret = da9055_rtc_device_init(rtc->da9055, pdata); + if (ret < 0) + goto err_rtc; + + ret = da9055_reg_read(rtc->da9055, DA9055_REG_ALARM_Y); + if (ret < 0) + goto err_rtc; + + if (ret & DA9055_RTC_ALM_EN) + rtc->alarm_enable = 1; + + device_init_wakeup(&pdev->dev, true); + + rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, + &da9055_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc->rtc)) { + ret = PTR_ERR(rtc->rtc); + goto err_rtc; + } + + alm_irq = platform_get_irq_byname(pdev, "ALM"); + if (alm_irq < 0) + return alm_irq; + + ret = devm_request_threaded_irq(&pdev->dev, alm_irq, NULL, + da9055_rtc_alm_irq, + IRQF_TRIGGER_HIGH | IRQF_ONESHOT, + "ALM", rtc); + if (ret != 0) + dev_err(rtc->da9055->dev, "irq registration failed: %d\n", ret); + +err_rtc: + return ret; + +} + +#ifdef CONFIG_PM +/* Turn off the alarm if it should not be a wake source. */ +static int da9055_rtc_suspend(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev); + int ret; + + if (!device_may_wakeup(&pdev->dev)) { + /* Disable the ALM IRQ */ + ret = da9055_rtc_enable_alarm(rtc, 0); + if (ret < 0) + dev_err(&pdev->dev, "Failed to disable RTC ALM\n"); + } + + return 0; +} + +/* Enable the alarm if it should be enabled (in case it was disabled to + * prevent use as a wake source). + */ +static int da9055_rtc_resume(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev); + int ret; + + if (!device_may_wakeup(&pdev->dev)) { + if (rtc->alarm_enable) { + ret = da9055_rtc_enable_alarm(rtc, 1); + if (ret < 0) + dev_err(&pdev->dev, + "Failed to restart RTC ALM\n"); + } + } + + return 0; +} + +/* Unconditionally disable the alarm */ +static int da9055_rtc_freeze(struct device *dev) +{ + struct platform_device *pdev = to_platform_device(dev); + struct da9055_rtc *rtc = dev_get_drvdata(&pdev->dev); + int ret; + + ret = da9055_rtc_enable_alarm(rtc, 0); + if (ret < 0) + dev_err(&pdev->dev, "Failed to freeze RTC ALMs\n"); + + return 0; + +} +#else +#define da9055_rtc_suspend NULL +#define da9055_rtc_resume NULL +#define da9055_rtc_freeze NULL +#endif + +static const struct dev_pm_ops da9055_rtc_pm_ops = { + .suspend = da9055_rtc_suspend, + .resume = da9055_rtc_resume, + + .freeze = da9055_rtc_freeze, + .thaw = da9055_rtc_resume, + .restore = da9055_rtc_resume, + + .poweroff = da9055_rtc_suspend, +}; + +static struct platform_driver da9055_rtc_driver = { + .probe = da9055_rtc_probe, + .driver = { + .name = "da9055-rtc", + .pm = &da9055_rtc_pm_ops, + }, +}; + +module_platform_driver(da9055_rtc_driver); + +MODULE_AUTHOR("David Dajun Chen "); +MODULE_DESCRIPTION("RTC driver for Dialog DA9055 PMIC"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:da9055-rtc"); -- cgit v1.3.1