From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/rtc/rtc-palmas.c | 362 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 362 insertions(+) create mode 100644 drivers/rtc/rtc-palmas.c (limited to 'drivers/rtc/rtc-palmas.c') diff --git a/drivers/rtc/rtc-palmas.c b/drivers/rtc/rtc-palmas.c new file mode 100644 index 000000000..aecada6bc --- /dev/null +++ b/drivers/rtc/rtc-palmas.c @@ -0,0 +1,362 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * rtc-palmas.c -- Palmas Real Time Clock driver. + + * RTC driver for TI Palma series devices like TPS65913, + * TPS65914 power management IC. + * + * Copyright (c) 2012, NVIDIA Corporation. + * + * Author: Laxman Dewangan + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct palmas_rtc { + struct rtc_device *rtc; + struct device *dev; + unsigned int irq; +}; + +/* Total number of RTC registers needed to set time*/ +#define PALMAS_NUM_TIME_REGS (PALMAS_YEARS_REG - PALMAS_SECONDS_REG + 1) + +static int palmas_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + unsigned char rtc_data[PALMAS_NUM_TIME_REGS]; + struct palmas *palmas = dev_get_drvdata(dev->parent); + int ret; + + /* Copy RTC counting registers to static registers or latches */ + ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG, + PALMAS_RTC_CTRL_REG_GET_TIME, PALMAS_RTC_CTRL_REG_GET_TIME); + if (ret < 0) { + dev_err(dev, "RTC CTRL reg update failed, err: %d\n", ret); + return ret; + } + + ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG, + rtc_data, PALMAS_NUM_TIME_REGS); + if (ret < 0) { + dev_err(dev, "RTC_SECONDS reg read failed, err = %d\n", ret); + return ret; + } + + tm->tm_sec = bcd2bin(rtc_data[0]); + tm->tm_min = bcd2bin(rtc_data[1]); + tm->tm_hour = bcd2bin(rtc_data[2]); + tm->tm_mday = bcd2bin(rtc_data[3]); + tm->tm_mon = bcd2bin(rtc_data[4]) - 1; + tm->tm_year = bcd2bin(rtc_data[5]) + 100; + + return ret; +} + +static int palmas_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + unsigned char rtc_data[PALMAS_NUM_TIME_REGS]; + struct palmas *palmas = dev_get_drvdata(dev->parent); + int ret; + + rtc_data[0] = bin2bcd(tm->tm_sec); + rtc_data[1] = bin2bcd(tm->tm_min); + rtc_data[2] = bin2bcd(tm->tm_hour); + rtc_data[3] = bin2bcd(tm->tm_mday); + rtc_data[4] = bin2bcd(tm->tm_mon + 1); + rtc_data[5] = bin2bcd(tm->tm_year - 100); + + /* Stop RTC while updating the RTC time registers */ + ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG, + PALMAS_RTC_CTRL_REG_STOP_RTC, 0); + if (ret < 0) { + dev_err(dev, "RTC stop failed, err = %d\n", ret); + return ret; + } + + ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE, PALMAS_SECONDS_REG, + rtc_data, PALMAS_NUM_TIME_REGS); + if (ret < 0) { + dev_err(dev, "RTC_SECONDS reg write failed, err = %d\n", ret); + return ret; + } + + /* Start back RTC */ + ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG, + PALMAS_RTC_CTRL_REG_STOP_RTC, PALMAS_RTC_CTRL_REG_STOP_RTC); + if (ret < 0) + dev_err(dev, "RTC start failed, err = %d\n", ret); + return ret; +} + +static int palmas_rtc_alarm_irq_enable(struct device *dev, unsigned enabled) +{ + struct palmas *palmas = dev_get_drvdata(dev->parent); + u8 val; + + val = enabled ? PALMAS_RTC_INTERRUPTS_REG_IT_ALARM : 0; + return palmas_write(palmas, PALMAS_RTC_BASE, + PALMAS_RTC_INTERRUPTS_REG, val); +} + +static int palmas_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned char alarm_data[PALMAS_NUM_TIME_REGS]; + u32 int_val; + struct palmas *palmas = dev_get_drvdata(dev->parent); + int ret; + + ret = palmas_bulk_read(palmas, PALMAS_RTC_BASE, + PALMAS_ALARM_SECONDS_REG, + alarm_data, PALMAS_NUM_TIME_REGS); + if (ret < 0) { + dev_err(dev, "RTC_ALARM_SECONDS read failed, err = %d\n", ret); + return ret; + } + + alm->time.tm_sec = bcd2bin(alarm_data[0]); + alm->time.tm_min = bcd2bin(alarm_data[1]); + alm->time.tm_hour = bcd2bin(alarm_data[2]); + alm->time.tm_mday = bcd2bin(alarm_data[3]); + alm->time.tm_mon = bcd2bin(alarm_data[4]) - 1; + alm->time.tm_year = bcd2bin(alarm_data[5]) + 100; + + ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_INTERRUPTS_REG, + &int_val); + if (ret < 0) { + dev_err(dev, "RTC_INTERRUPTS reg read failed, err = %d\n", ret); + return ret; + } + + if (int_val & PALMAS_RTC_INTERRUPTS_REG_IT_ALARM) + alm->enabled = 1; + return ret; +} + +static int palmas_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned char alarm_data[PALMAS_NUM_TIME_REGS]; + struct palmas *palmas = dev_get_drvdata(dev->parent); + int ret; + + ret = palmas_rtc_alarm_irq_enable(dev, 0); + if (ret < 0) { + dev_err(dev, "Disable RTC alarm failed\n"); + return ret; + } + + alarm_data[0] = bin2bcd(alm->time.tm_sec); + alarm_data[1] = bin2bcd(alm->time.tm_min); + alarm_data[2] = bin2bcd(alm->time.tm_hour); + alarm_data[3] = bin2bcd(alm->time.tm_mday); + alarm_data[4] = bin2bcd(alm->time.tm_mon + 1); + alarm_data[5] = bin2bcd(alm->time.tm_year - 100); + + ret = palmas_bulk_write(palmas, PALMAS_RTC_BASE, + PALMAS_ALARM_SECONDS_REG, alarm_data, PALMAS_NUM_TIME_REGS); + if (ret < 0) { + dev_err(dev, "ALARM_SECONDS_REG write failed, err = %d\n", ret); + return ret; + } + + if (alm->enabled) + ret = palmas_rtc_alarm_irq_enable(dev, 1); + return ret; +} + +static int palmas_clear_interrupts(struct device *dev) +{ + struct palmas *palmas = dev_get_drvdata(dev->parent); + unsigned int rtc_reg; + int ret; + + ret = palmas_read(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG, + &rtc_reg); + if (ret < 0) { + dev_err(dev, "RTC_STATUS read failed, err = %d\n", ret); + return ret; + } + + ret = palmas_write(palmas, PALMAS_RTC_BASE, PALMAS_RTC_STATUS_REG, + rtc_reg); + if (ret < 0) { + dev_err(dev, "RTC_STATUS write failed, err = %d\n", ret); + return ret; + } + return 0; +} + +static irqreturn_t palmas_rtc_interrupt(int irq, void *context) +{ + struct palmas_rtc *palmas_rtc = context; + struct device *dev = palmas_rtc->dev; + int ret; + + ret = palmas_clear_interrupts(dev); + if (ret < 0) { + dev_err(dev, "RTC interrupt clear failed, err = %d\n", ret); + return IRQ_NONE; + } + + rtc_update_irq(palmas_rtc->rtc, 1, RTC_IRQF | RTC_AF); + return IRQ_HANDLED; +} + +static const struct rtc_class_ops palmas_rtc_ops = { + .read_time = palmas_rtc_read_time, + .set_time = palmas_rtc_set_time, + .read_alarm = palmas_rtc_read_alarm, + .set_alarm = palmas_rtc_set_alarm, + .alarm_irq_enable = palmas_rtc_alarm_irq_enable, +}; + +static int palmas_rtc_probe(struct platform_device *pdev) +{ + struct palmas *palmas = dev_get_drvdata(pdev->dev.parent); + struct palmas_rtc *palmas_rtc = NULL; + int ret; + bool enable_bb_charging = false; + bool high_bb_charging = false; + + if (pdev->dev.of_node) { + enable_bb_charging = of_property_read_bool(pdev->dev.of_node, + "ti,backup-battery-chargeable"); + high_bb_charging = of_property_read_bool(pdev->dev.of_node, + "ti,backup-battery-charge-high-current"); + } + + palmas_rtc = devm_kzalloc(&pdev->dev, sizeof(struct palmas_rtc), + GFP_KERNEL); + if (!palmas_rtc) + return -ENOMEM; + + /* Clear pending interrupts */ + ret = palmas_clear_interrupts(&pdev->dev); + if (ret < 0) { + dev_err(&pdev->dev, "clear RTC int failed, err = %d\n", ret); + return ret; + } + + palmas_rtc->dev = &pdev->dev; + platform_set_drvdata(pdev, palmas_rtc); + + if (enable_bb_charging) { + unsigned reg = PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG; + + if (high_bb_charging) + reg = 0; + + ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE, + PALMAS_BACKUP_BATTERY_CTRL, + PALMAS_BACKUP_BATTERY_CTRL_BBS_BBC_LOW_ICHRG, reg); + if (ret < 0) { + dev_err(&pdev->dev, + "BACKUP_BATTERY_CTRL update failed, %d\n", ret); + return ret; + } + + ret = palmas_update_bits(palmas, PALMAS_PMU_CONTROL_BASE, + PALMAS_BACKUP_BATTERY_CTRL, + PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN, + PALMAS_BACKUP_BATTERY_CTRL_BB_CHG_EN); + if (ret < 0) { + dev_err(&pdev->dev, + "BACKUP_BATTERY_CTRL update failed, %d\n", ret); + return ret; + } + } + + /* Start RTC */ + ret = palmas_update_bits(palmas, PALMAS_RTC_BASE, PALMAS_RTC_CTRL_REG, + PALMAS_RTC_CTRL_REG_STOP_RTC, + PALMAS_RTC_CTRL_REG_STOP_RTC); + if (ret < 0) { + dev_err(&pdev->dev, "RTC_CTRL write failed, err = %d\n", ret); + return ret; + } + + palmas_rtc->irq = platform_get_irq(pdev, 0); + + device_init_wakeup(&pdev->dev, true); + palmas_rtc->rtc = devm_rtc_device_register(&pdev->dev, pdev->name, + &palmas_rtc_ops, THIS_MODULE); + if (IS_ERR(palmas_rtc->rtc)) { + ret = PTR_ERR(palmas_rtc->rtc); + dev_err(&pdev->dev, "RTC register failed, err = %d\n", ret); + return ret; + } + + ret = devm_request_threaded_irq(&pdev->dev, palmas_rtc->irq, NULL, + palmas_rtc_interrupt, + IRQF_TRIGGER_LOW | IRQF_ONESHOT, + dev_name(&pdev->dev), palmas_rtc); + if (ret < 0) { + dev_err(&pdev->dev, "IRQ request failed, err = %d\n", ret); + return ret; + } + + return 0; +} + +static void palmas_rtc_remove(struct platform_device *pdev) +{ + palmas_rtc_alarm_irq_enable(&pdev->dev, 0); +} + +#ifdef CONFIG_PM_SLEEP +static int palmas_rtc_suspend(struct device *dev) +{ + struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + enable_irq_wake(palmas_rtc->irq); + return 0; +} + +static int palmas_rtc_resume(struct device *dev) +{ + struct palmas_rtc *palmas_rtc = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + disable_irq_wake(palmas_rtc->irq); + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(palmas_rtc_pm_ops, palmas_rtc_suspend, + palmas_rtc_resume); + +#ifdef CONFIG_OF +static const struct of_device_id of_palmas_rtc_match[] = { + { .compatible = "ti,palmas-rtc"}, + { }, +}; +MODULE_DEVICE_TABLE(of, of_palmas_rtc_match); +#endif + +static struct platform_driver palmas_rtc_driver = { + .probe = palmas_rtc_probe, + .remove = palmas_rtc_remove, + .driver = { + .name = "palmas-rtc", + .pm = &palmas_rtc_pm_ops, + .of_match_table = of_match_ptr(of_palmas_rtc_match), + }, +}; + +module_platform_driver(palmas_rtc_driver); + +MODULE_ALIAS("platform:palmas_rtc"); +MODULE_DESCRIPTION("TI PALMAS series RTC driver"); +MODULE_AUTHOR("Laxman Dewangan "); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1