linux/drivers/watchdog/lpc18xx_wdt.c
Uwe Kleine-König fb22b9e95a watchdog: lpc18xx: 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 (mostly) ignored
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.

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>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230303213716.2123717-17-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-04-22 12:53:46 +02:00

291 lines
8.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* NXP LPC18xx Watchdog Timer (WDT)
*
* Copyright (c) 2015 Ariel D'Alessandro <ariel@vanguardiasur.com>
*
* Notes
* -----
* The Watchdog consists of a fixed divide-by-4 clock pre-scaler and a 24-bit
* counter which decrements on every clock cycle.
*/
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>
/* Registers */
#define LPC18XX_WDT_MOD 0x00
#define LPC18XX_WDT_MOD_WDEN BIT(0)
#define LPC18XX_WDT_MOD_WDRESET BIT(1)
#define LPC18XX_WDT_TC 0x04
#define LPC18XX_WDT_TC_MIN 0xff
#define LPC18XX_WDT_TC_MAX 0xffffff
#define LPC18XX_WDT_FEED 0x08
#define LPC18XX_WDT_FEED_MAGIC1 0xaa
#define LPC18XX_WDT_FEED_MAGIC2 0x55
#define LPC18XX_WDT_TV 0x0c
/* Clock pre-scaler */
#define LPC18XX_WDT_CLK_DIV 4
/* Timeout values in seconds */
#define LPC18XX_WDT_DEF_TIMEOUT 30U
static int heartbeat;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds (default="
__MODULE_STRING(LPC18XX_WDT_DEF_TIMEOUT) ")");
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) ")");
struct lpc18xx_wdt_dev {
struct watchdog_device wdt_dev;
struct clk *reg_clk;
struct clk *wdt_clk;
unsigned long clk_rate;
void __iomem *base;
struct timer_list timer;
spinlock_t lock;
};
static int lpc18xx_wdt_feed(struct watchdog_device *wdt_dev)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
unsigned long flags;
/*
* An abort condition will occur if an interrupt happens during the feed
* sequence.
*/
spin_lock_irqsave(&lpc18xx_wdt->lock, flags);
writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
writel(LPC18XX_WDT_FEED_MAGIC2, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
spin_unlock_irqrestore(&lpc18xx_wdt->lock, flags);
return 0;
}
static void lpc18xx_wdt_timer_feed(struct timer_list *t)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = from_timer(lpc18xx_wdt, t, timer);
struct watchdog_device *wdt_dev = &lpc18xx_wdt->wdt_dev;
lpc18xx_wdt_feed(wdt_dev);
/* Use safe value (1/2 of real timeout) */
mod_timer(&lpc18xx_wdt->timer, jiffies +
msecs_to_jiffies((wdt_dev->timeout * MSEC_PER_SEC) / 2));
}
/*
* Since LPC18xx Watchdog cannot be disabled in hardware, we must keep feeding
* it with a timer until userspace watchdog software takes over.
*/
static int lpc18xx_wdt_stop(struct watchdog_device *wdt_dev)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
lpc18xx_wdt_timer_feed(&lpc18xx_wdt->timer);
return 0;
}
static void __lpc18xx_wdt_set_timeout(struct lpc18xx_wdt_dev *lpc18xx_wdt)
{
unsigned int val;
val = DIV_ROUND_UP(lpc18xx_wdt->wdt_dev.timeout * lpc18xx_wdt->clk_rate,
LPC18XX_WDT_CLK_DIV);
writel(val, lpc18xx_wdt->base + LPC18XX_WDT_TC);
}
static int lpc18xx_wdt_set_timeout(struct watchdog_device *wdt_dev,
unsigned int new_timeout)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
lpc18xx_wdt->wdt_dev.timeout = new_timeout;
__lpc18xx_wdt_set_timeout(lpc18xx_wdt);
return 0;
}
static unsigned int lpc18xx_wdt_get_timeleft(struct watchdog_device *wdt_dev)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
unsigned int val;
val = readl(lpc18xx_wdt->base + LPC18XX_WDT_TV);
return (val * LPC18XX_WDT_CLK_DIV) / lpc18xx_wdt->clk_rate;
}
static int lpc18xx_wdt_start(struct watchdog_device *wdt_dev)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
unsigned int val;
if (timer_pending(&lpc18xx_wdt->timer))
del_timer(&lpc18xx_wdt->timer);
val = readl(lpc18xx_wdt->base + LPC18XX_WDT_MOD);
val |= LPC18XX_WDT_MOD_WDEN;
val |= LPC18XX_WDT_MOD_WDRESET;
writel(val, lpc18xx_wdt->base + LPC18XX_WDT_MOD);
/*
* Setting the WDEN bit in the WDMOD register is not sufficient to
* enable the Watchdog. A valid feed sequence must be completed after
* setting WDEN before the Watchdog is capable of generating a reset.
*/
lpc18xx_wdt_feed(wdt_dev);
return 0;
}
static int lpc18xx_wdt_restart(struct watchdog_device *wdt_dev,
unsigned long action, void *data)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(wdt_dev);
unsigned long flags;
int val;
/*
* Incorrect feed sequence causes immediate watchdog reset if enabled.
*/
spin_lock_irqsave(&lpc18xx_wdt->lock, flags);
val = readl(lpc18xx_wdt->base + LPC18XX_WDT_MOD);
val |= LPC18XX_WDT_MOD_WDEN;
val |= LPC18XX_WDT_MOD_WDRESET;
writel(val, lpc18xx_wdt->base + LPC18XX_WDT_MOD);
writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
writel(LPC18XX_WDT_FEED_MAGIC2, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
writel(LPC18XX_WDT_FEED_MAGIC1, lpc18xx_wdt->base + LPC18XX_WDT_FEED);
spin_unlock_irqrestore(&lpc18xx_wdt->lock, flags);
return 0;
}
static const struct watchdog_info lpc18xx_wdt_info = {
.identity = "NXP LPC18xx Watchdog",
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
WDIOF_MAGICCLOSE,
};
static const struct watchdog_ops lpc18xx_wdt_ops = {
.owner = THIS_MODULE,
.start = lpc18xx_wdt_start,
.stop = lpc18xx_wdt_stop,
.ping = lpc18xx_wdt_feed,
.set_timeout = lpc18xx_wdt_set_timeout,
.get_timeleft = lpc18xx_wdt_get_timeleft,
.restart = lpc18xx_wdt_restart,
};
static int lpc18xx_wdt_probe(struct platform_device *pdev)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt;
struct device *dev = &pdev->dev;
lpc18xx_wdt = devm_kzalloc(dev, sizeof(*lpc18xx_wdt), GFP_KERNEL);
if (!lpc18xx_wdt)
return -ENOMEM;
lpc18xx_wdt->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(lpc18xx_wdt->base))
return PTR_ERR(lpc18xx_wdt->base);
lpc18xx_wdt->reg_clk = devm_clk_get_enabled(dev, "reg");
if (IS_ERR(lpc18xx_wdt->reg_clk)) {
dev_err(dev, "failed to get the reg clock\n");
return PTR_ERR(lpc18xx_wdt->reg_clk);
}
lpc18xx_wdt->wdt_clk = devm_clk_get_enabled(dev, "wdtclk");
if (IS_ERR(lpc18xx_wdt->wdt_clk)) {
dev_err(dev, "failed to get the wdt clock\n");
return PTR_ERR(lpc18xx_wdt->wdt_clk);
}
/* We use the clock rate to calculate timeouts */
lpc18xx_wdt->clk_rate = clk_get_rate(lpc18xx_wdt->wdt_clk);
if (lpc18xx_wdt->clk_rate == 0) {
dev_err(dev, "failed to get clock rate\n");
return -EINVAL;
}
lpc18xx_wdt->wdt_dev.info = &lpc18xx_wdt_info;
lpc18xx_wdt->wdt_dev.ops = &lpc18xx_wdt_ops;
lpc18xx_wdt->wdt_dev.min_timeout = DIV_ROUND_UP(LPC18XX_WDT_TC_MIN *
LPC18XX_WDT_CLK_DIV, lpc18xx_wdt->clk_rate);
lpc18xx_wdt->wdt_dev.max_timeout = (LPC18XX_WDT_TC_MAX *
LPC18XX_WDT_CLK_DIV) / lpc18xx_wdt->clk_rate;
lpc18xx_wdt->wdt_dev.timeout = min(lpc18xx_wdt->wdt_dev.max_timeout,
LPC18XX_WDT_DEF_TIMEOUT);
spin_lock_init(&lpc18xx_wdt->lock);
lpc18xx_wdt->wdt_dev.parent = dev;
watchdog_set_drvdata(&lpc18xx_wdt->wdt_dev, lpc18xx_wdt);
watchdog_init_timeout(&lpc18xx_wdt->wdt_dev, heartbeat, dev);
__lpc18xx_wdt_set_timeout(lpc18xx_wdt);
timer_setup(&lpc18xx_wdt->timer, lpc18xx_wdt_timer_feed, 0);
watchdog_set_nowayout(&lpc18xx_wdt->wdt_dev, nowayout);
watchdog_set_restart_priority(&lpc18xx_wdt->wdt_dev, 128);
platform_set_drvdata(pdev, lpc18xx_wdt);
watchdog_stop_on_reboot(&lpc18xx_wdt->wdt_dev);
return devm_watchdog_register_device(dev, &lpc18xx_wdt->wdt_dev);
}
static void lpc18xx_wdt_remove(struct platform_device *pdev)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);
dev_warn(&pdev->dev, "I quit now, hardware will probably reboot!\n");
del_timer_sync(&lpc18xx_wdt->timer);
}
static const struct of_device_id lpc18xx_wdt_match[] = {
{ .compatible = "nxp,lpc1850-wwdt" },
{}
};
MODULE_DEVICE_TABLE(of, lpc18xx_wdt_match);
static struct platform_driver lpc18xx_wdt_driver = {
.driver = {
.name = "lpc18xx-wdt",
.of_match_table = lpc18xx_wdt_match,
},
.probe = lpc18xx_wdt_probe,
.remove_new = lpc18xx_wdt_remove,
};
module_platform_driver(lpc18xx_wdt_driver);
MODULE_AUTHOR("Ariel D'Alessandro <ariel@vanguardiasur.com.ar>");
MODULE_DESCRIPTION("NXP LPC18xx Watchdog Timer Driver");
MODULE_LICENSE("GPL v2");