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linux/drivers/watchdog/pm8916_wdt.c
Stephan Gerhold 066951ca33 watchdog: pm8916_wdt: Handle watchdog enabled by bootloader 
The bootloader might already enable the watchdog to catch hangs
during the boot process. In that case the kernel needs to ping
the watchdog temporarily until userspace is fully started.

Add a check for this in the probe() function and set the WDOG_HW_RUNNING
flag to make the watchdog core handle this automatically.

Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220629084816.125515-4-stephan.gerhold@kernkonzept.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2022-07-23 14:21:28 +02:00

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// SPDX-License-Identifier: GPL-2.0
#include <linux/bitops.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/property.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/watchdog.h>
#define PON_POFF_REASON1 0x0c
#define PON_POFF_REASON1_PMIC_WD BIT(2)
#define PON_POFF_REASON2 0x0d
#define PON_POFF_REASON2_UVLO BIT(5)
#define PON_POFF_REASON2_OTST3 BIT(6)
#define PON_INT_RT_STS 0x10
#define PMIC_WD_BARK_STS_BIT BIT(6)
#define PON_PMIC_WD_RESET_S1_TIMER 0x54
#define PON_PMIC_WD_RESET_S2_TIMER 0x55
#define PON_PMIC_WD_RESET_S2_CTL 0x56
#define RESET_TYPE_WARM 0x01
#define RESET_TYPE_SHUTDOWN 0x04
#define RESET_TYPE_HARD 0x07
#define PON_PMIC_WD_RESET_S2_CTL2 0x57
#define S2_RESET_EN_BIT BIT(7)
#define PON_PMIC_WD_RESET_PET 0x58
#define WATCHDOG_PET_BIT BIT(0)
#define PM8916_WDT_DEFAULT_TIMEOUT 32
#define PM8916_WDT_MIN_TIMEOUT 1
#define PM8916_WDT_MAX_TIMEOUT 127
struct pm8916_wdt {
struct regmap *regmap;
struct watchdog_device wdev;
u32 baseaddr;
};
static int pm8916_wdt_start(struct watchdog_device *wdev)
{
struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
return regmap_update_bits(wdt->regmap,
wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
S2_RESET_EN_BIT, S2_RESET_EN_BIT);
}
static int pm8916_wdt_stop(struct watchdog_device *wdev)
{
struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
return regmap_update_bits(wdt->regmap,
wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
S2_RESET_EN_BIT, 0);
}
static int pm8916_wdt_ping(struct watchdog_device *wdev)
{
struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
return regmap_write(wdt->regmap, wdt->baseaddr + PON_PMIC_WD_RESET_PET,
WATCHDOG_PET_BIT);
}
static int pm8916_wdt_configure_timers(struct watchdog_device *wdev)
{
struct pm8916_wdt *wdt = watchdog_get_drvdata(wdev);
int err;
err = regmap_write(wdt->regmap,
wdt->baseaddr + PON_PMIC_WD_RESET_S1_TIMER,
wdev->timeout - wdev->pretimeout);
if (err)
return err;
return regmap_write(wdt->regmap,
wdt->baseaddr + PON_PMIC_WD_RESET_S2_TIMER,
wdev->pretimeout);
}
static int pm8916_wdt_set_timeout(struct watchdog_device *wdev,
unsigned int timeout)
{
wdev->timeout = timeout;
return pm8916_wdt_configure_timers(wdev);
}
static int pm8916_wdt_set_pretimeout(struct watchdog_device *wdev,
unsigned int pretimeout)
{
wdev->pretimeout = pretimeout;
return pm8916_wdt_configure_timers(wdev);
}
static irqreturn_t pm8916_wdt_isr(int irq, void *arg)
{
struct pm8916_wdt *wdt = arg;
int err, sts;
err = regmap_read(wdt->regmap, wdt->baseaddr + PON_INT_RT_STS, &sts);
if (err)
return IRQ_HANDLED;
if (sts & PMIC_WD_BARK_STS_BIT)
watchdog_notify_pretimeout(&wdt->wdev);
return IRQ_HANDLED;
}
static const struct watchdog_info pm8916_wdt_ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE |
WDIOF_OVERHEAT | WDIOF_CARDRESET | WDIOF_POWERUNDER,
.identity = "QCOM PM8916 PON WDT",
};
static const struct watchdog_info pm8916_wdt_pt_ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE |
WDIOF_OVERHEAT | WDIOF_CARDRESET | WDIOF_POWERUNDER |
WDIOF_PRETIMEOUT,
.identity = "QCOM PM8916 PON WDT",
};
static const struct watchdog_ops pm8916_wdt_ops = {
.owner = THIS_MODULE,
.start = pm8916_wdt_start,
.stop = pm8916_wdt_stop,
.ping = pm8916_wdt_ping,
.set_timeout = pm8916_wdt_set_timeout,
.set_pretimeout = pm8916_wdt_set_pretimeout,
};
static int pm8916_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct pm8916_wdt *wdt;
struct device *parent;
unsigned int val;
int err, irq;
u8 poff[2];
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
parent = dev->parent;
/*
* The pm8916-pon-wdt is a child of the pon device, which is a child
* of the pm8916 mfd device. We want access to the pm8916 registers.
* Retrieve regmap from pm8916 (parent->parent) and base address
* from pm8916-pon (pon).
*/
wdt->regmap = dev_get_regmap(parent->parent, NULL);
if (!wdt->regmap) {
dev_err(dev, "failed to locate regmap\n");
return -ENODEV;
}
err = device_property_read_u32(parent, "reg", &wdt->baseaddr);
if (err) {
dev_err(dev, "failed to get pm8916-pon address\n");
return err;
}
irq = platform_get_irq(pdev, 0);
if (irq > 0) {
err = devm_request_irq(dev, irq, pm8916_wdt_isr, 0,
"pm8916_wdt", wdt);
if (err)
return err;
wdt->wdev.info = &pm8916_wdt_pt_ident;
} else {
if (irq == -EPROBE_DEFER)
return -EPROBE_DEFER;
wdt->wdev.info = &pm8916_wdt_ident;
}
err = regmap_bulk_read(wdt->regmap, wdt->baseaddr + PON_POFF_REASON1,
&poff, ARRAY_SIZE(poff));
if (err) {
dev_err(dev, "failed to read POFF reason: %d\n", err);
return err;
}
dev_dbg(dev, "POFF reason: %#x %#x\n", poff[0], poff[1]);
if (poff[0] & PON_POFF_REASON1_PMIC_WD)
wdt->wdev.bootstatus |= WDIOF_CARDRESET;
if (poff[1] & PON_POFF_REASON2_UVLO)
wdt->wdev.bootstatus |= WDIOF_POWERUNDER;
if (poff[1] & PON_POFF_REASON2_OTST3)
wdt->wdev.bootstatus |= WDIOF_OVERHEAT;
err = regmap_read(wdt->regmap, wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL2,
&val);
if (err) {
dev_err(dev, "failed to check if watchdog is active: %d\n", err);
return err;
}
if (val & S2_RESET_EN_BIT)
set_bit(WDOG_HW_RUNNING, &wdt->wdev.status);
/* Configure watchdog to hard-reset mode */
err = regmap_write(wdt->regmap,
wdt->baseaddr + PON_PMIC_WD_RESET_S2_CTL,
RESET_TYPE_HARD);
if (err) {
dev_err(dev, "failed configure watchdog\n");
return err;
}
wdt->wdev.ops = &pm8916_wdt_ops,
wdt->wdev.parent = dev;
wdt->wdev.min_timeout = PM8916_WDT_MIN_TIMEOUT;
wdt->wdev.max_timeout = PM8916_WDT_MAX_TIMEOUT;
wdt->wdev.timeout = PM8916_WDT_DEFAULT_TIMEOUT;
wdt->wdev.pretimeout = 0;
watchdog_set_drvdata(&wdt->wdev, wdt);
platform_set_drvdata(pdev, wdt);
watchdog_init_timeout(&wdt->wdev, 0, dev);
pm8916_wdt_configure_timers(&wdt->wdev);
return devm_watchdog_register_device(dev, &wdt->wdev);
}
static int __maybe_unused pm8916_wdt_suspend(struct device *dev)
{
struct pm8916_wdt *wdt = dev_get_drvdata(dev);
if (watchdog_active(&wdt->wdev))
return pm8916_wdt_stop(&wdt->wdev);
return 0;
}
static int __maybe_unused pm8916_wdt_resume(struct device *dev)
{
struct pm8916_wdt *wdt = dev_get_drvdata(dev);
if (watchdog_active(&wdt->wdev))
return pm8916_wdt_start(&wdt->wdev);
return 0;
}
static SIMPLE_DEV_PM_OPS(pm8916_wdt_pm_ops, pm8916_wdt_suspend,
pm8916_wdt_resume);
static const struct of_device_id pm8916_wdt_id_table[] = {
{ .compatible = "qcom,pm8916-wdt" },
{ }
};
MODULE_DEVICE_TABLE(of, pm8916_wdt_id_table);
static struct platform_driver pm8916_wdt_driver = {
.probe = pm8916_wdt_probe,
.driver = {
.name = "pm8916-wdt",
.of_match_table = of_match_ptr(pm8916_wdt_id_table),
.pm = &pm8916_wdt_pm_ops,
},
};
module_platform_driver(pm8916_wdt_driver);
MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
MODULE_DESCRIPTION("Qualcomm pm8916 watchdog driver");
MODULE_LICENSE("GPL v2");
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