Release 4.12 drivers/watchdog/lpc18xx_wdt.c
/*
* NXP LPC18xx Watchdog Timer (WDT)
*
* Copyright (c) 2015 Ariel D'Alessandro <ariel@vanguardiasur.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* 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;
}
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static void lpc18xx_wdt_timer_feed(unsigned long data)
{
struct watchdog_device *wdt_dev = (struct watchdog_device *)data;
struct lpc18xx_wdt_dev *lpc18xx_wdt = watchdog_get_drvdata(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));
}
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/*
* 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)
{
lpc18xx_wdt_timer_feed((unsigned long)wdt_dev);
return 0;
}
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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);
}
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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;
}
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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;
}
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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;
}
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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;
}
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| Total | 134 | 100.00% | 3 | 100.00% |
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;
struct resource *res;
int ret;
lpc18xx_wdt = devm_kzalloc(dev, sizeof(*lpc18xx_wdt), GFP_KERNEL);
if (!lpc18xx_wdt)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
lpc18xx_wdt->base = devm_ioremap_resource(dev, res);
if (IS_ERR(lpc18xx_wdt->base))
return PTR_ERR(lpc18xx_wdt->base);
lpc18xx_wdt->reg_clk = devm_clk_get(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(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);
}
ret = clk_prepare_enable(lpc18xx_wdt->reg_clk);
if (ret) {
dev_err(dev, "could not prepare or enable sys clock\n");
return ret;
}
ret = clk_prepare_enable(lpc18xx_wdt->wdt_clk);
if (ret) {
dev_err(dev, "could not prepare or enable wdt clock\n");
goto disable_reg_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");
ret = -EINVAL;
goto disable_wdt_clk;
}
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);
ret = watchdog_init_timeout(&lpc18xx_wdt->wdt_dev, heartbeat, dev);
__lpc18xx_wdt_set_timeout(lpc18xx_wdt);
setup_timer(&lpc18xx_wdt->timer, lpc18xx_wdt_timer_feed,
(unsigned long)&lpc18xx_wdt->wdt_dev);
watchdog_set_nowayout(&lpc18xx_wdt->wdt_dev, nowayout);
watchdog_set_restart_priority(&lpc18xx_wdt->wdt_dev, 128);
platform_set_drvdata(pdev, lpc18xx_wdt);
ret = watchdog_register_device(&lpc18xx_wdt->wdt_dev);
if (ret)
goto disable_wdt_clk;
return 0;
disable_wdt_clk:
clk_disable_unprepare(lpc18xx_wdt->wdt_clk);
disable_reg_clk:
clk_disable_unprepare(lpc18xx_wdt->reg_clk);
return ret;
}
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| Total | 458 | 100.00% | 2 | 100.00% |
static void lpc18xx_wdt_shutdown(struct platform_device *pdev)
{
struct lpc18xx_wdt_dev *lpc18xx_wdt = platform_get_drvdata(pdev);
lpc18xx_wdt_stop(&lpc18xx_wdt->wdt_dev);
}
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static int 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(&lpc18xx_wdt->timer);
watchdog_unregister_device(&lpc18xx_wdt->wdt_dev);
clk_disable_unprepare(lpc18xx_wdt->wdt_clk);
clk_disable_unprepare(lpc18xx_wdt->reg_clk);
return 0;
}
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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 = lpc18xx_wdt_remove,
.shutdown = lpc18xx_wdt_shutdown,
};
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");
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| Damien Riegel | 79 | 5.81% | 1 | 20.00% |
| Guenter Roeck | 8 | 0.59% | 1 | 20.00% |
| Fengguang Wu | 1 | 0.07% | 1 | 20.00% |
| Bhumika Goyal | 1 | 0.07% | 1 | 20.00% |
| Total | 1359 | 100.00% | 5 | 100.00% |
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