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-tps6594.c | 504 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 504 insertions(+) create mode 100644 drivers/rtc/rtc-tps6594.c (limited to 'drivers/rtc/rtc-tps6594.c') diff --git a/drivers/rtc/rtc-tps6594.c b/drivers/rtc/rtc-tps6594.c new file mode 100644 index 000000000..f89fc3e59 --- /dev/null +++ b/drivers/rtc/rtc-tps6594.c @@ -0,0 +1,504 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * RTC driver for tps6594 PMIC + * + * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/ + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +// Total number of RTC registers needed to set time +#define NUM_TIME_REGS (TPS6594_REG_RTC_WEEKS - TPS6594_REG_RTC_SECONDS + 1) + +// Total number of RTC alarm registers +#define NUM_TIME_ALARM_REGS (NUM_TIME_REGS - 1) + +/* + * Min and max values supported by 'offset' interface (swapped sign). + * After conversion, the values do not exceed the range [-32767, 33767] + * which COMP_REG must conform to. + */ +#define MIN_OFFSET (-277774) +#define MAX_OFFSET (277774) + +// Number of ticks per hour +#define TICKS_PER_HOUR (32768 * 3600LL) + +// Multiplier for ppb conversions +#define PPB_MULT NANO + +struct tps6594_rtc { + struct rtc_device *rtc_dev; + int irq; +}; + +static int tps6594_rtc_alarm_irq_enable(struct device *dev, + unsigned int enabled) +{ + struct tps6594 *tps = dev_get_drvdata(dev->parent); + u8 val; + + val = enabled ? TPS6594_BIT_IT_ALARM : 0; + + return regmap_update_bits(tps->regmap, TPS6594_REG_RTC_INTERRUPTS, + TPS6594_BIT_IT_ALARM, val); +} + +/* Pulse GET_TIME field of RTC_CTRL_1 to store a timestamp in shadow registers. */ +static int tps6594_rtc_shadow_timestamp(struct device *dev, struct tps6594 *tps) +{ + int ret; + + /* + * Set GET_TIME to 0. Next time we set GET_TIME to 1 we will be sure to store + * an up-to-date timestamp. + */ + ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, + TPS6594_BIT_GET_TIME); + if (ret < 0) + return ret; + + /* + * Copy content of RTC registers to shadow registers or latches to read + * a coherent timestamp. + */ + return regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, + TPS6594_BIT_GET_TIME); +} + +static int tps6594_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + unsigned char rtc_data[NUM_TIME_REGS]; + struct tps6594 *tps = dev_get_drvdata(dev->parent); + int ret; + + // Check if RTC is running. + ret = regmap_test_bits(tps->regmap, TPS6594_REG_RTC_STATUS, + TPS6594_BIT_RUN); + if (ret < 0) + return ret; + if (ret == 0) + return -EINVAL; + + ret = tps6594_rtc_shadow_timestamp(dev, tps); + if (ret < 0) + return ret; + + // Read shadowed RTC registers. + ret = regmap_bulk_read(tps->regmap, TPS6594_REG_RTC_SECONDS, rtc_data, + NUM_TIME_REGS); + if (ret < 0) + 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; + tm->tm_wday = bcd2bin(rtc_data[6]); + + return 0; +} + +static int tps6594_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + unsigned char rtc_data[NUM_TIME_REGS]; + struct tps6594 *tps = 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); + rtc_data[6] = bin2bcd(tm->tm_wday); + + // Stop RTC while updating the RTC time registers. + ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, + TPS6594_BIT_STOP_RTC); + if (ret < 0) + return ret; + + // Update all the time registers in one shot. + ret = regmap_bulk_write(tps->regmap, TPS6594_REG_RTC_SECONDS, rtc_data, + NUM_TIME_REGS); + if (ret < 0) + return ret; + + // Start back RTC. + return regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, + TPS6594_BIT_STOP_RTC); +} + +static int tps6594_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned char alarm_data[NUM_TIME_ALARM_REGS]; + u32 int_val; + struct tps6594 *tps = dev_get_drvdata(dev->parent); + int ret; + + ret = regmap_bulk_read(tps->regmap, TPS6594_REG_ALARM_SECONDS, + alarm_data, NUM_TIME_ALARM_REGS); + if (ret < 0) + 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 = regmap_read(tps->regmap, TPS6594_REG_RTC_INTERRUPTS, &int_val); + if (ret < 0) + return ret; + + alm->enabled = int_val & TPS6594_BIT_IT_ALARM; + + return 0; +} + +static int tps6594_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alm) +{ + unsigned char alarm_data[NUM_TIME_ALARM_REGS]; + struct tps6594 *tps = dev_get_drvdata(dev->parent); + int ret; + + // Disable alarm irq before changing the alarm timestamp. + ret = tps6594_rtc_alarm_irq_enable(dev, 0); + if (ret) + 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); + + // Update all the alarm registers in one shot. + ret = regmap_bulk_write(tps->regmap, TPS6594_REG_ALARM_SECONDS, + alarm_data, NUM_TIME_ALARM_REGS); + if (ret < 0) + return ret; + + if (alm->enabled) + ret = tps6594_rtc_alarm_irq_enable(dev, 1); + + return ret; +} + +static int tps6594_rtc_set_calibration(struct device *dev, int calibration) +{ + struct tps6594 *tps = dev_get_drvdata(dev->parent); + __le16 value; + int ret; + + /* + * TPS6594 uses two's complement 16 bit value for compensation of RTC + * crystal inaccuracies. One time every hour when seconds counter + * increments from 0 to 1 compensation value will be added to internal + * RTC counter value. + * + * Valid range for compensation value: [-32767 .. 32767]. + */ + if (calibration < S16_MIN + 1 || calibration > S16_MAX) + return -ERANGE; + + value = cpu_to_le16(calibration); + + // Update all the compensation registers in one shot. + ret = regmap_bulk_write(tps->regmap, TPS6594_REG_RTC_COMP_LSB, &value, + sizeof(value)); + if (ret < 0) + return ret; + + // Enable automatic compensation. + return regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, + TPS6594_BIT_AUTO_COMP); +} + +static int tps6594_rtc_get_calibration(struct device *dev, int *calibration) +{ + struct tps6594 *tps = dev_get_drvdata(dev->parent); + unsigned int ctrl; + __le16 value; + int ret; + + ret = regmap_read(tps->regmap, TPS6594_REG_RTC_CTRL_1, &ctrl); + if (ret < 0) + return ret; + + // If automatic compensation is not enabled report back zero. + if (!(ctrl & TPS6594_BIT_AUTO_COMP)) { + *calibration = 0; + return 0; + } + + ret = regmap_bulk_read(tps->regmap, TPS6594_REG_RTC_COMP_LSB, &value, + sizeof(value)); + if (ret < 0) + return ret; + + *calibration = le16_to_cpu(value); + + return 0; +} + +static int tps6594_rtc_read_offset(struct device *dev, long *offset) +{ + int calibration; + s64 tmp; + int ret; + + ret = tps6594_rtc_get_calibration(dev, &calibration); + if (ret < 0) + return ret; + + // Convert from RTC calibration register format to ppb format. + tmp = calibration * PPB_MULT; + + if (tmp < 0) + tmp -= TICKS_PER_HOUR / 2LL; + else + tmp += TICKS_PER_HOUR / 2LL; + tmp = div_s64(tmp, TICKS_PER_HOUR); + + /* + * SAFETY: + * Computatiion is the reverse operation of the one done in + * `tps6594_rtc_set_offset`. The safety remarks applie here too. + */ + + /* + * Offset value operates in negative way, so swap sign. + * See 8.3.10.5, (32768 - COMP_REG). + */ + *offset = (long)-tmp; + + return 0; +} + +static int tps6594_rtc_set_offset(struct device *dev, long offset) +{ + int calibration; + s64 tmp; + + // Make sure offset value is within supported range. + if (offset < MIN_OFFSET || offset > MAX_OFFSET) + return -ERANGE; + + // Convert from ppb format to RTC calibration register format. + + tmp = offset * TICKS_PER_HOUR; + if (tmp < 0) + tmp -= PPB_MULT / 2LL; + else + tmp += PPB_MULT / 2LL; + tmp = div_s64(tmp, PPB_MULT); + + /* + * SAFETY: + * - tmp = offset * TICK_PER_HOUR : + * `offset` can't be more than 277774, so `tmp` can't exceed 277774000000000 + * which is lower than the maximum value in an `s64` (2^63-1). No overflow here. + * + * - tmp += TICK_PER_HOUR / 2LL : + * tmp will have a maximum value of 277774117964800 which is still inferior to 2^63-1. + */ + + // Offset value operates in negative way, so swap sign. + calibration = (int)-tmp; + + return tps6594_rtc_set_calibration(dev, calibration); +} + +static irqreturn_t tps6594_rtc_interrupt(int irq, void *data) +{ + struct device *dev = data; + struct tps6594 *tps = dev_get_drvdata(dev->parent); + struct tps6594_rtc *rtc = dev_get_drvdata(dev); + int ret; + u32 rtc_reg; + + ret = regmap_read(tps->regmap, TPS6594_REG_RTC_STATUS, &rtc_reg); + if (ret) + return IRQ_NONE; + + rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); + + return IRQ_HANDLED; +} + +static const struct rtc_class_ops tps6594_rtc_ops = { + .read_time = tps6594_rtc_read_time, + .set_time = tps6594_rtc_set_time, + .read_alarm = tps6594_rtc_read_alarm, + .set_alarm = tps6594_rtc_set_alarm, + .alarm_irq_enable = tps6594_rtc_alarm_irq_enable, + .read_offset = tps6594_rtc_read_offset, + .set_offset = tps6594_rtc_set_offset, +}; + +static int tps6594_rtc_probe(struct platform_device *pdev) +{ + struct tps6594 *tps = dev_get_drvdata(pdev->dev.parent); + struct device *dev = &pdev->dev; + struct tps6594_rtc *rtc; + int irq; + int ret; + + rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + rtc->rtc_dev = devm_rtc_allocate_device(dev); + if (IS_ERR(rtc->rtc_dev)) + return PTR_ERR(rtc->rtc_dev); + + // Enable crystal oscillator. + ret = regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_2, + TPS6594_BIT_XTAL_EN); + if (ret < 0) + return ret; + + ret = regmap_test_bits(tps->regmap, TPS6594_REG_RTC_STATUS, + TPS6594_BIT_RUN); + if (ret < 0) + return ret; + // RTC not running. + if (ret == 0) { + ret = regmap_set_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, + TPS6594_BIT_STOP_RTC); + if (ret < 0) + return ret; + + /* + * On some boards, a 40 ms delay is needed before BIT_RUN is set. + * 80 ms should provide sufficient margin. + */ + mdelay(80); + + /* + * RTC should be running now. Check if this is the case. + * If not it might be a missing oscillator. + */ + ret = regmap_test_bits(tps->regmap, TPS6594_REG_RTC_STATUS, + TPS6594_BIT_RUN); + if (ret < 0) + return ret; + if (ret == 0) + return -ENODEV; + + // Stop RTC until first call to `tps6594_rtc_set_time`. + ret = regmap_clear_bits(tps->regmap, TPS6594_REG_RTC_CTRL_1, + TPS6594_BIT_STOP_RTC); + if (ret < 0) + return ret; + } + + platform_set_drvdata(pdev, rtc); + + irq = platform_get_irq_byname(pdev, TPS6594_IRQ_NAME_ALARM); + if (irq < 0) + return dev_err_probe(dev, irq, "Failed to get irq\n"); + + rtc->irq = irq; + + ret = devm_request_threaded_irq(dev, irq, NULL, tps6594_rtc_interrupt, + IRQF_ONESHOT, TPS6594_IRQ_NAME_ALARM, + dev); + if (ret < 0) + return dev_err_probe(dev, ret, + "Failed to request_threaded_irq\n"); + + ret = device_init_wakeup(dev, true); + if (ret < 0) + return dev_err_probe(dev, ret, + "Failed to init rtc as wakeup source\n"); + + rtc->rtc_dev->ops = &tps6594_rtc_ops; + rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_2000; + rtc->rtc_dev->range_max = RTC_TIMESTAMP_END_2099; + + return devm_rtc_register_device(rtc->rtc_dev); +} + +static int tps6594_rtc_resume(struct device *dev) +{ + struct tps6594 *tps = dev_get_drvdata(dev->parent); + struct tps6594_rtc *rtc = dev_get_drvdata(dev); + int ret; + + ret = regmap_test_bits(tps->regmap, TPS6594_REG_INT_STARTUP, + TPS6594_BIT_RTC_INT); + if (ret < 0) { + dev_err(dev, "failed to read REG_INT_STARTUP: %d\n", ret); + goto out; + } + + if (ret > 0) { + /* + * If the alarm bit is set, it means that the IRQ has been + * fired. But, the kernel may not have woke up yet when it + * happened. So, we have to clear it. + */ + ret = regmap_write(tps->regmap, TPS6594_REG_RTC_STATUS, + TPS6594_BIT_ALARM); + if (ret < 0) + dev_err(dev, "error clearing alarm bit: %d", ret); + + rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); + } +out: + disable_irq_wake(rtc->irq); + + return 0; +} + +static int tps6594_rtc_suspend(struct device *dev) +{ + struct tps6594_rtc *rtc = dev_get_drvdata(dev); + + enable_irq_wake(rtc->irq); + + return 0; +} + +static DEFINE_SIMPLE_DEV_PM_OPS(tps6594_rtc_pm_ops, tps6594_rtc_suspend, tps6594_rtc_resume); + +static const struct platform_device_id tps6594_rtc_id_table[] = { + { .name = "tps6594-rtc" }, + { } +}; +MODULE_DEVICE_TABLE(platform, tps6594_rtc_id_table); + +static struct platform_driver tps6594_rtc_driver = { + .probe = tps6594_rtc_probe, + .driver = { + .name = "tps6594-rtc", + .pm = pm_sleep_ptr(&tps6594_rtc_pm_ops), + }, + .id_table = tps6594_rtc_id_table, +}; + +module_platform_driver(tps6594_rtc_driver); +MODULE_AUTHOR("Esteban Blanc "); +MODULE_DESCRIPTION("TPS6594 RTC driver"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1