drivers/watchdog/max63xx_wdt.c - linux - Git at Google

 /*
  * drivers/char/watchdog/max63xx_wdt.c
  *
  * Driver for max63{69,70,71,72,73,74} watchdog timers
  *
  * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2. This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  *
  * This driver assumes the watchdog pins are memory mapped (as it is
  * the case for the Arcom Zeus). Should it be connected over GPIOs or
  * another interface, some abstraction will have to be introduced.
  */

 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/mod_devicetable.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/watchdog.h>
 #include <linux/bitops.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
 #include <linux/io.h>
 #include <linux/slab.h>

 #define DEFAULT_HEARTBEAT 60
 #define MAX_HEARTBEAT     60

 static unsigned int heartbeat = DEFAULT_HEARTBEAT;
 static bool nowayout  = WATCHDOG_NOWAYOUT;

 /*
  * Memory mapping: a single byte, 3 first lower bits to select bit 3
  * to ping the watchdog.
  */
 #define MAX6369_WDSET	(7 << 0)
 #define MAX6369_WDI	(1 << 3)

 #define MAX6369_WDSET_DISABLED	3

 static int nodelay;

 struct max63xx_wdt {
 	struct watchdog_device wdd;
 	const struct max63xx_timeout *timeout;

 	/* memory mapping */
 	void __iomem *base;
 	spinlock_t lock;

 	/* WDI and WSET bits write access routines */
 	void (*ping)(struct max63xx_wdt *wdt);
 	void (*set)(struct max63xx_wdt *wdt, u8 set);
 };

 /*
  * The timeout values used are actually the absolute minimum the chip
  * offers. Typical values on my board are slightly over twice as long
  * (10s setting ends up with a 25s timeout), and can be up to 3 times
  * the nominal setting (according to the datasheet). So please take
  * these values with a grain of salt. Same goes for the initial delay
  * "feature". Only max6373/74 have a few settings without this initial
  * delay (selected with the "nodelay" parameter).
  *
  * I also decided to remove from the tables any timeout smaller than a
  * second, as it looked completly overkill...
  */

 /* Timeouts in second */
 struct max63xx_timeout {
 	const u8 wdset;
 	const u8 tdelay;
 	const u8 twd;
 };

 static const struct max63xx_timeout max6369_table[] = {
 	{ 5,  1,  1 },
 	{ 6, 10, 10 },
 	{ 7, 60, 60 },
 	{ },
 };

 static const struct max63xx_timeout max6371_table[] = {
 	{ 6, 60,  3 },
 	{ 7, 60, 60 },
 	{ },
 };

 static const struct max63xx_timeout max6373_table[] = {
 	{ 2, 60,  1 },
 	{ 5,  0,  1 },
 	{ 1,  3,  3 },
 	{ 7, 60, 10 },
 	{ 6,  0, 10 },
 	{ },
 };

 static struct max63xx_timeout *
 max63xx_select_timeout(struct max63xx_timeout *table, int value)
 {
 	while (table->twd) {
 		if (value <= table->twd) {
 			if (nodelay && table->tdelay == 0)
 				return table;

 			if (!nodelay)
 				return table;
 		}

 		table++;
 	}

 	return NULL;
 }

 static int max63xx_wdt_ping(struct watchdog_device *wdd)
 {
 	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);

 	wdt->ping(wdt);
 	return 0;
 }

 static int max63xx_wdt_start(struct watchdog_device *wdd)
 {
 	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);

 	wdt->set(wdt, wdt->timeout->wdset);

 	/* check for a edge triggered startup */
 	if (wdt->timeout->tdelay == 0)
 		wdt->ping(wdt);
 	return 0;
 }

 static int max63xx_wdt_stop(struct watchdog_device *wdd)
 {
 	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);

 	wdt->set(wdt, MAX6369_WDSET_DISABLED);
 	return 0;
 }

 static const struct watchdog_ops max63xx_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = max63xx_wdt_start,
 	.stop = max63xx_wdt_stop,
 	.ping = max63xx_wdt_ping,
 };

 static const struct watchdog_info max63xx_wdt_info = {
 	.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 	.identity = "max63xx Watchdog",
 };

 static void max63xx_mmap_ping(struct max63xx_wdt *wdt)
 {
 	u8 val;

 	spin_lock(&wdt->lock);

 	val = __raw_readb(wdt->base);

 	__raw_writeb(val | MAX6369_WDI, wdt->base);
 	__raw_writeb(val & ~MAX6369_WDI, wdt->base);

 	spin_unlock(&wdt->lock);
 }

 static void max63xx_mmap_set(struct max63xx_wdt *wdt, u8 set)
 {
 	u8 val;

 	spin_lock(&wdt->lock);

 	val = __raw_readb(wdt->base);
 	val &= ~MAX6369_WDSET;
 	val |= set & MAX6369_WDSET;
 	__raw_writeb(val, wdt->base);

 	spin_unlock(&wdt->lock);
 }

 static int max63xx_mmap_init(struct platform_device *p, struct max63xx_wdt *wdt)
 {
 	wdt->base = devm_platform_ioremap_resource(p, 0);
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);

 	spin_lock_init(&wdt->lock);

 	wdt->ping = max63xx_mmap_ping;
 	wdt->set = max63xx_mmap_set;
 	return 0;
 }

 static int max63xx_wdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct max63xx_wdt *wdt;
 	struct max63xx_timeout *table;
 	int err;

 	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 	if (!wdt)
 		return -ENOMEM;

 	table = (struct max63xx_timeout *)pdev->id_entry->driver_data;

 	if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
 		heartbeat = DEFAULT_HEARTBEAT;

 	wdt->timeout = max63xx_select_timeout(table, heartbeat);
 	if (!wdt->timeout) {
 		dev_err(dev, "unable to satisfy %ds heartbeat request\n",
 			heartbeat);
 		return -EINVAL;
 	}

 	err = max63xx_mmap_init(pdev, wdt);
 	if (err)
 		return err;

 	platform_set_drvdata(pdev, &wdt->wdd);
 	watchdog_set_drvdata(&wdt->wdd, wdt);

 	wdt->wdd.parent = dev;
 	wdt->wdd.timeout = wdt->timeout->twd;
 	wdt->wdd.info = &max63xx_wdt_info;
 	wdt->wdd.ops = &max63xx_wdt_ops;

 	watchdog_set_nowayout(&wdt->wdd, nowayout);

 	err = devm_watchdog_register_device(dev, &wdt->wdd);
 	if (err)
 		return err;

 	dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
 		 wdt->timeout->twd, wdt->timeout->tdelay);
 	return 0;
 }

 static const struct platform_device_id max63xx_id_table[] = {
 	{ "max6369_wdt", (kernel_ulong_t)max6369_table, },
 	{ "max6370_wdt", (kernel_ulong_t)max6369_table, },
 	{ "max6371_wdt", (kernel_ulong_t)max6371_table, },
 	{ "max6372_wdt", (kernel_ulong_t)max6371_table, },
 	{ "max6373_wdt", (kernel_ulong_t)max6373_table, },
 	{ "max6374_wdt", (kernel_ulong_t)max6373_table, },
 	{ },
 };
 MODULE_DEVICE_TABLE(platform, max63xx_id_table);

 static struct platform_driver max63xx_wdt_driver = {
 	.probe		= max63xx_wdt_probe,
 	.id_table	= max63xx_id_table,
 	.driver		= {
 		.name	= "max63xx_wdt",
 	},
 };

 module_platform_driver(max63xx_wdt_driver);

 MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
 MODULE_DESCRIPTION("max63xx Watchdog Driver");

 module_param(heartbeat, int, 0);
 MODULE_PARM_DESC(heartbeat,
 		 "Watchdog heartbeat period in seconds from 1 to "
 		 __MODULE_STRING(MAX_HEARTBEAT) ", default "
 		 __MODULE_STRING(DEFAULT_HEARTBEAT));

 module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

 module_param(nodelay, int, 0);
 MODULE_PARM_DESC(nodelay,
 		 "Force selection of a timeout setting without initial delay "
 		 "(max6373/74 only, default=0)");

 MODULE_LICENSE("GPL v2");
	/*
	* drivers/char/watchdog/max63xx_wdt.c
	*
	* Driver for max63{69,70,71,72,73,74} watchdog timers
	*
	* Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*
	* This driver assumes the watchdog pins are memory mapped (as it is
	* the case for the Arcom Zeus). Should it be connected over GPIOs or
	* another interface, some abstraction will have to be introduced.
	*/

	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/mod_devicetable.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/watchdog.h>
	#include <linux/bitops.h>
	#include <linux/platform_device.h>
	#include <linux/spinlock.h>
	#include <linux/io.h>
	#include <linux/slab.h>

	#define DEFAULT_HEARTBEAT 60
	#define MAX_HEARTBEAT 60

	static unsigned int heartbeat = DEFAULT_HEARTBEAT;
	static bool nowayout = WATCHDOG_NOWAYOUT;

	/*
	* Memory mapping: a single byte, 3 first lower bits to select bit 3
	* to ping the watchdog.
	*/
	#define MAX6369_WDSET (7 << 0)
	#define MAX6369_WDI (1 << 3)

	#define MAX6369_WDSET_DISABLED 3

	static int nodelay;

	struct max63xx_wdt {
	struct watchdog_device wdd;
	const struct max63xx_timeout *timeout;

	/* memory mapping */
	void __iomem *base;
	spinlock_t lock;

	/* WDI and WSET bits write access routines */
	void (ping)(struct max63xx_wdt wdt);
	void (set)(struct max63xx_wdt wdt, u8 set);
	};

	/*
	* The timeout values used are actually the absolute minimum the chip
	* offers. Typical values on my board are slightly over twice as long
	* (10s setting ends up with a 25s timeout), and can be up to 3 times
	* the nominal setting (according to the datasheet). So please take
	* these values with a grain of salt. Same goes for the initial delay
	* "feature". Only max6373/74 have a few settings without this initial
	* delay (selected with the "nodelay" parameter).
	*
	* I also decided to remove from the tables any timeout smaller than a
	* second, as it looked completly overkill...
	*/

	/* Timeouts in second */
	struct max63xx_timeout {
	const u8 wdset;
	const u8 tdelay;
	const u8 twd;
	};

	static const struct max63xx_timeout max6369_table[] = {
	{ 5, 1, 1 },
	{ 6, 10, 10 },
	{ 7, 60, 60 },
	{ },
	};

	static const struct max63xx_timeout max6371_table[] = {
	{ 6, 60, 3 },
	{ 7, 60, 60 },
	{ },
	};

	static const struct max63xx_timeout max6373_table[] = {
	{ 2, 60, 1 },
	{ 5, 0, 1 },
	{ 1, 3, 3 },
	{ 7, 60, 10 },
	{ 6, 0, 10 },
	{ },
	};

	static struct max63xx_timeout *
	max63xx_select_timeout(struct max63xx_timeout *table, int value)
	{
	while (table->twd) {
	if (value <= table->twd) {
	if (nodelay && table->tdelay == 0)
	return table;

	if (!nodelay)
	return table;
	}

	table++;
	}

	return NULL;
	}

	static int max63xx_wdt_ping(struct watchdog_device *wdd)
	{
	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);

	wdt->ping(wdt);
	return 0;
	}

	static int max63xx_wdt_start(struct watchdog_device *wdd)
	{
	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);

	wdt->set(wdt, wdt->timeout->wdset);

	/* check for a edge triggered startup */
	if (wdt->timeout->tdelay == 0)
	wdt->ping(wdt);
	return 0;
	}

	static int max63xx_wdt_stop(struct watchdog_device *wdd)
	{
	struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);

	wdt->set(wdt, MAX6369_WDSET_DISABLED);
	return 0;
	}

	static const struct watchdog_ops max63xx_wdt_ops = {
	.owner = THIS_MODULE,
	.start = max63xx_wdt_start,
	.stop = max63xx_wdt_stop,
	.ping = max63xx_wdt_ping,
	};

	static const struct watchdog_info max63xx_wdt_info = {
	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE,
	.identity = "max63xx Watchdog",
	};

	static void max63xx_mmap_ping(struct max63xx_wdt *wdt)
	{
	u8 val;

	spin_lock(&wdt->lock);

	val = __raw_readb(wdt->base);

	__raw_writeb(val \| MAX6369_WDI, wdt->base);
	__raw_writeb(val & ~MAX6369_WDI, wdt->base);

	spin_unlock(&wdt->lock);
	}

	static void max63xx_mmap_set(struct max63xx_wdt *wdt, u8 set)
	{
	u8 val;

	spin_lock(&wdt->lock);

	val = __raw_readb(wdt->base);
	val &= ~MAX6369_WDSET;
	val \|= set & MAX6369_WDSET;
	__raw_writeb(val, wdt->base);

	spin_unlock(&wdt->lock);
	}

	static int max63xx_mmap_init(struct platform_device p, struct max63xx_wdt wdt)
	{
	wdt->base = devm_platform_ioremap_resource(p, 0);
	if (IS_ERR(wdt->base))
	return PTR_ERR(wdt->base);

	spin_lock_init(&wdt->lock);

	wdt->ping = max63xx_mmap_ping;
	wdt->set = max63xx_mmap_set;
	return 0;
	}

	static int max63xx_wdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct max63xx_wdt *wdt;
	struct max63xx_timeout *table;
	int err;

	wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
	if (!wdt)
	return -ENOMEM;

	table = (struct max63xx_timeout *)pdev->id_entry->driver_data;

	if (heartbeat < 1 \|\| heartbeat > MAX_HEARTBEAT)
	heartbeat = DEFAULT_HEARTBEAT;

	wdt->timeout = max63xx_select_timeout(table, heartbeat);
	if (!wdt->timeout) {
	dev_err(dev, "unable to satisfy %ds heartbeat request\n",
	heartbeat);
	return -EINVAL;
	}

	err = max63xx_mmap_init(pdev, wdt);
	if (err)
	return err;

	platform_set_drvdata(pdev, &wdt->wdd);
	watchdog_set_drvdata(&wdt->wdd, wdt);

	wdt->wdd.parent = dev;
	wdt->wdd.timeout = wdt->timeout->twd;
	wdt->wdd.info = &max63xx_wdt_info;
	wdt->wdd.ops = &max63xx_wdt_ops;

	watchdog_set_nowayout(&wdt->wdd, nowayout);

	err = devm_watchdog_register_device(dev, &wdt->wdd);
	if (err)
	return err;

	dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
	wdt->timeout->twd, wdt->timeout->tdelay);
	return 0;
	}

	static const struct platform_device_id max63xx_id_table[] = {
	{ "max6369_wdt", (kernel_ulong_t)max6369_table, },
	{ "max6370_wdt", (kernel_ulong_t)max6369_table, },
	{ "max6371_wdt", (kernel_ulong_t)max6371_table, },
	{ "max6372_wdt", (kernel_ulong_t)max6371_table, },
	{ "max6373_wdt", (kernel_ulong_t)max6373_table, },
	{ "max6374_wdt", (kernel_ulong_t)max6373_table, },
	{ },
	};
	MODULE_DEVICE_TABLE(platform, max63xx_id_table);

	static struct platform_driver max63xx_wdt_driver = {
	.probe = max63xx_wdt_probe,
	.id_table = max63xx_id_table,
	.driver = {
	.name = "max63xx_wdt",
	},
	};

	module_platform_driver(max63xx_wdt_driver);

	MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
	MODULE_DESCRIPTION("max63xx Watchdog Driver");

	module_param(heartbeat, int, 0);
	MODULE_PARM_DESC(heartbeat,
	"Watchdog heartbeat period in seconds from 1 to "
	__MODULE_STRING(MAX_HEARTBEAT) ", default "
	__MODULE_STRING(DEFAULT_HEARTBEAT));

	module_param(nowayout, bool, 0);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

	module_param(nodelay, int, 0);
	MODULE_PARM_DESC(nodelay,
	"Force selection of a timeout setting without initial delay "
	"(max6373/74 only, default=0)");

	MODULE_LICENSE("GPL v2");