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linux/drivers/watchdog/at91sam9_wdt.c
Uwe Kleine-König 6a7b3de6a3 watchdog: at91sam9_wdt: Convert to platform remove callback returning void 
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20231106154807.3866712-4-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-12-17 16:14:19 +01:00

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// SPDX-License-Identifier: GPL-2.0+
/*
* Watchdog driver for Atmel AT91SAM9x processors.
*
* Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr
*
*/
/*
* The Watchdog Timer Mode Register can be only written to once. If the
* timeout need to be set from Linux, be sure that the bootstrap or the
* bootloader doesn't write to this register.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include "at91sam9_wdt.h"
#define DRV_NAME "AT91SAM9 Watchdog"
#define wdt_read(wdt, field) \
readl_relaxed((wdt)->base + (field))
#define wdt_write(wtd, field, val) \
writel_relaxed((val), (wdt)->base + (field))
/* AT91SAM9 watchdog runs a 12bit counter @ 256Hz,
* use this to convert a watchdog
* value from/to milliseconds.
*/
#define ticks_to_hz_rounddown(t) ((((t) + 1) * HZ) >> 8)
#define ticks_to_hz_roundup(t) (((((t) + 1) * HZ) + 255) >> 8)
#define ticks_to_secs(t) (((t) + 1) >> 8)
#define secs_to_ticks(s) ((s) ? (((s) << 8) - 1) : 0)
#define WDT_MR_RESET 0x3FFF2FFF
/* Watchdog max counter value in ticks */
#define WDT_COUNTER_MAX_TICKS 0xFFF
/* Watchdog max delta/value in secs */
#define WDT_COUNTER_MAX_SECS ticks_to_secs(WDT_COUNTER_MAX_TICKS)
/* Hardware timeout in seconds */
#define WDT_HW_TIMEOUT 2
/* Timer heartbeat (500ms) */
#define WDT_TIMEOUT (HZ/2)
/* User land timeout */
#define WDT_HEARTBEAT 15
static int heartbeat;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
#define to_wdt(wdd) container_of(wdd, struct at91wdt, wdd)
struct at91wdt {
struct watchdog_device wdd;
void __iomem *base;
unsigned long next_heartbeat; /* the next_heartbeat for the timer */
struct timer_list timer; /* The timer that pings the watchdog */
u32 mr;
u32 mr_mask;
unsigned long heartbeat; /* WDT heartbeat in jiffies */
bool nowayout;
unsigned int irq;
struct clk *sclk;
};
/* ......................................................................... */
static irqreturn_t wdt_interrupt(int irq, void *dev_id)
{
struct at91wdt *wdt = (struct at91wdt *)dev_id;
if (wdt_read(wdt, AT91_WDT_SR)) {
pr_crit("at91sam9 WDT software reset\n");
emergency_restart();
pr_crit("Reboot didn't ?????\n");
}
return IRQ_HANDLED;
}
/*
* Reload the watchdog timer. (ie, pat the watchdog)
*/
static inline void at91_wdt_reset(struct at91wdt *wdt)
{
wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
}
/*
* Timer tick
*/
static void at91_ping(struct timer_list *t)
{
struct at91wdt *wdt = from_timer(wdt, t, timer);
if (time_before(jiffies, wdt->next_heartbeat) ||
!watchdog_active(&wdt->wdd)) {
at91_wdt_reset(wdt);
mod_timer(&wdt->timer, jiffies + wdt->heartbeat);
} else {
pr_crit("I will reset your machine !\n");
}
}
static int at91_wdt_start(struct watchdog_device *wdd)
{
struct at91wdt *wdt = to_wdt(wdd);
/* calculate when the next userspace timeout will be */
wdt->next_heartbeat = jiffies + wdd->timeout * HZ;
return 0;
}
static int at91_wdt_stop(struct watchdog_device *wdd)
{
/* The watchdog timer hardware can not be stopped... */
return 0;
}
static int at91_wdt_set_timeout(struct watchdog_device *wdd, unsigned int new_timeout)
{
wdd->timeout = new_timeout;
return at91_wdt_start(wdd);
}
static int at91_wdt_init(struct platform_device *pdev, struct at91wdt *wdt)
{
u32 tmp;
u32 delta;
u32 value;
int err;
u32 mask = wdt->mr_mask;
unsigned long min_heartbeat = 1;
unsigned long max_heartbeat;
struct device *dev = &pdev->dev;
tmp = wdt_read(wdt, AT91_WDT_MR);
if ((tmp & mask) != (wdt->mr & mask)) {
if (tmp == WDT_MR_RESET) {
wdt_write(wdt, AT91_WDT_MR, wdt->mr);
tmp = wdt_read(wdt, AT91_WDT_MR);
}
}
if (tmp & AT91_WDT_WDDIS) {
if (wdt->mr & AT91_WDT_WDDIS)
return 0;
dev_err(dev, "watchdog is disabled\n");
return -EINVAL;
}
value = tmp & AT91_WDT_WDV;
delta = (tmp & AT91_WDT_WDD) >> 16;
if (delta < value)
min_heartbeat = ticks_to_hz_roundup(value - delta);
max_heartbeat = ticks_to_hz_rounddown(value);
if (!max_heartbeat) {
dev_err(dev,
"heartbeat is too small for the system to handle it correctly\n");
return -EINVAL;
}
/*
* Try to reset the watchdog counter 4 or 2 times more often than
* actually requested, to avoid spurious watchdog reset.
* If this is not possible because of the min_heartbeat value, reset
* it at the min_heartbeat period.
*/
if ((max_heartbeat / 4) >= min_heartbeat)
wdt->heartbeat = max_heartbeat / 4;
else if ((max_heartbeat / 2) >= min_heartbeat)
wdt->heartbeat = max_heartbeat / 2;
else
wdt->heartbeat = min_heartbeat;
if (max_heartbeat < min_heartbeat + 4)
dev_warn(dev,
"min heartbeat and max heartbeat might be too close for the system to handle it correctly\n");
if ((tmp & AT91_WDT_WDFIEN) && wdt->irq) {
err = devm_request_irq(dev, wdt->irq, wdt_interrupt,
IRQF_SHARED | IRQF_IRQPOLL | IRQF_NO_SUSPEND,
pdev->name, wdt);
if (err)
return err;
}
if ((tmp & wdt->mr_mask) != (wdt->mr & wdt->mr_mask))
dev_warn(dev,
"watchdog already configured differently (mr = %x expecting %x)\n",
tmp & wdt->mr_mask, wdt->mr & wdt->mr_mask);
timer_setup(&wdt->timer, at91_ping, 0);
/*
* Use min_heartbeat the first time to avoid spurious watchdog reset:
* we don't know for how long the watchdog counter is running, and
* - resetting it right now might trigger a watchdog fault reset
* - waiting for heartbeat time might lead to a watchdog timeout
* reset
*/
mod_timer(&wdt->timer, jiffies + min_heartbeat);
/* Try to set timeout from device tree first */
if (watchdog_init_timeout(&wdt->wdd, 0, dev))
watchdog_init_timeout(&wdt->wdd, heartbeat, dev);
watchdog_set_nowayout(&wdt->wdd, wdt->nowayout);
err = watchdog_register_device(&wdt->wdd);
if (err)
goto out_stop_timer;
wdt->next_heartbeat = jiffies + wdt->wdd.timeout * HZ;
return 0;
out_stop_timer:
del_timer(&wdt->timer);
return err;
}
/* ......................................................................... */
static const struct watchdog_info at91_wdt_info = {
.identity = DRV_NAME,
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops at91_wdt_ops = {
.owner = THIS_MODULE,
.start = at91_wdt_start,
.stop = at91_wdt_stop,
.set_timeout = at91_wdt_set_timeout,
};
#if defined(CONFIG_OF)
static int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt)
{
u32 min = 0;
u32 max = WDT_COUNTER_MAX_SECS;
const char *tmp;
/* Get the interrupts property */
wdt->irq = irq_of_parse_and_map(np, 0);
if (!wdt->irq)
dev_warn(wdt->wdd.parent, "failed to get IRQ from DT\n");
if (!of_property_read_u32_index(np, "atmel,max-heartbeat-sec", 0,
&max)) {
if (!max || max > WDT_COUNTER_MAX_SECS)
max = WDT_COUNTER_MAX_SECS;
if (!of_property_read_u32_index(np, "atmel,min-heartbeat-sec",
0, &min)) {
if (min >= max)
min = max - 1;
}
}
min = secs_to_ticks(min);
max = secs_to_ticks(max);
wdt->mr_mask = 0x3FFFFFFF;
wdt->mr = 0;
if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
!strcmp(tmp, "software")) {
wdt->mr |= AT91_WDT_WDFIEN;
wdt->mr_mask &= ~AT91_WDT_WDRPROC;
} else {
wdt->mr |= AT91_WDT_WDRSTEN;
}
if (!of_property_read_string(np, "atmel,reset-type", &tmp) &&
!strcmp(tmp, "proc"))
wdt->mr |= AT91_WDT_WDRPROC;
if (of_property_read_bool(np, "atmel,disable")) {
wdt->mr |= AT91_WDT_WDDIS;
wdt->mr_mask &= AT91_WDT_WDDIS;
}
if (of_property_read_bool(np, "atmel,idle-halt"))
wdt->mr |= AT91_WDT_WDIDLEHLT;
if (of_property_read_bool(np, "atmel,dbg-halt"))
wdt->mr |= AT91_WDT_WDDBGHLT;
wdt->mr |= max | ((max - min) << 16);
return 0;
}
#else
static inline int of_at91wdt_init(struct device_node *np, struct at91wdt *wdt)
{
return 0;
}
#endif
static int at91wdt_probe(struct platform_device *pdev)
{
int err;
struct at91wdt *wdt;
wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdt->mr = (WDT_HW_TIMEOUT * 256) | AT91_WDT_WDRSTEN | AT91_WDT_WDD |
AT91_WDT_WDDBGHLT | AT91_WDT_WDIDLEHLT;
wdt->mr_mask = 0x3FFFFFFF;
wdt->nowayout = nowayout;
wdt->wdd.parent = &pdev->dev;
wdt->wdd.info = &at91_wdt_info;
wdt->wdd.ops = &at91_wdt_ops;
wdt->wdd.timeout = WDT_HEARTBEAT;
wdt->wdd.min_timeout = 1;
wdt->wdd.max_timeout = 0xFFFF;
wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(wdt->base))
return PTR_ERR(wdt->base);
wdt->sclk = devm_clk_get_enabled(&pdev->dev, NULL);
if (IS_ERR(wdt->sclk)) {
dev_err(&pdev->dev, "Could not enable slow clock\n");
return PTR_ERR(wdt->sclk);
}
if (pdev->dev.of_node) {
err = of_at91wdt_init(pdev->dev.of_node, wdt);
if (err)
return err;
}
err = at91_wdt_init(pdev, wdt);
if (err)
return err;
platform_set_drvdata(pdev, wdt);
pr_info("enabled (heartbeat=%d sec, nowayout=%d)\n",
wdt->wdd.timeout, wdt->nowayout);
return 0;
}
static void at91wdt_remove(struct platform_device *pdev)
{
struct at91wdt *wdt = platform_get_drvdata(pdev);
watchdog_unregister_device(&wdt->wdd);
pr_warn("I quit now, hardware will probably reboot!\n");
del_timer(&wdt->timer);
}
#if defined(CONFIG_OF)
static const struct of_device_id at91_wdt_dt_ids[] = {
{ .compatible = "atmel,at91sam9260-wdt" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, at91_wdt_dt_ids);
#endif
static struct platform_driver at91wdt_driver = {
.probe = at91wdt_probe,
.remove_new = at91wdt_remove,
.driver = {
.name = "at91_wdt",
.of_match_table = of_match_ptr(at91_wdt_dt_ids),
},
};
module_platform_driver(at91wdt_driver);
MODULE_AUTHOR("Renaud CERRATO <r.cerrato@til-technologies.fr>");
MODULE_DESCRIPTION("Watchdog driver for Atmel AT91SAM9x processors");
MODULE_LICENSE("GPL");
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