drivers/watchdog/max63xx_wdt.c - kernel/lockdown - 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/types.h>
 #include <linux/kernel.h>
 #include <linux/watchdog.h>
 #include <linux/init.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)

 static DEFINE_SPINLOCK(io_lock);

 static int nodelay;
 static void __iomem	*wdt_base;

 /*
  * 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 {
 	u8 wdset;
 	u8 tdelay;
 	u8 twd;
 };

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

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

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

 static struct max63xx_timeout *current_timeout;

 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)
 {
 	u8 val;

 	spin_lock(&io_lock);

 	val = __raw_readb(wdt_base);

 	__raw_writeb(val | MAX6369_WDI, wdt_base);
 	__raw_writeb(val & ~MAX6369_WDI, wdt_base);

 	spin_unlock(&io_lock);
 	return 0;
 }

 static int max63xx_wdt_start(struct watchdog_device *wdd)
 {
 	struct max63xx_timeout *entry = watchdog_get_drvdata(wdd);
 	u8 val;

 	spin_lock(&io_lock);

 	val = __raw_readb(wdt_base);
 	val &= ~MAX6369_WDSET;
 	val |= entry->wdset;
 	__raw_writeb(val, wdt_base);

 	spin_unlock(&io_lock);

 	/* check for a edge triggered startup */
 	if (entry->tdelay == 0)
 		max63xx_wdt_ping(wdd);
 	return 0;
 }

 static int max63xx_wdt_stop(struct watchdog_device *wdd)
 {
 	u8 val;

 	spin_lock(&io_lock);

 	val = __raw_readb(wdt_base);
 	val &= ~MAX6369_WDSET;
 	val |= 3;
 	__raw_writeb(val, wdt_base);

 	spin_unlock(&io_lock);
 	return 0;
 }

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

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

 static struct watchdog_device max63xx_wdt_dev = {
 	.info = &max63xx_wdt_info,
 	.ops = &max63xx_wdt_ops,
 };

 static int max63xx_wdt_probe(struct platform_device *pdev)
 {
 	struct resource	*wdt_mem;
 	struct max63xx_timeout *table;

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

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

 	dev_info(&pdev->dev, "requesting %ds heartbeat\n", heartbeat);
 	current_timeout = max63xx_select_timeout(table, heartbeat);

 	if (!current_timeout) {
 		dev_err(&pdev->dev, "unable to satisfy heartbeat request\n");
 		return -EINVAL;
 	}

 	dev_info(&pdev->dev, "using %ds heartbeat with %ds initial delay\n",
 		 current_timeout->twd, current_timeout->tdelay);

 	heartbeat = current_timeout->twd;

 	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	wdt_base = devm_ioremap_resource(&pdev->dev, wdt_mem);
 	if (IS_ERR(wdt_base))
 		return PTR_ERR(wdt_base);

 	max63xx_wdt_dev.timeout = heartbeat;
 	watchdog_set_nowayout(&max63xx_wdt_dev, nowayout);
 	watchdog_set_drvdata(&max63xx_wdt_dev, current_timeout);

 	return watchdog_register_device(&max63xx_wdt_dev);
 }

 static int max63xx_wdt_remove(struct platform_device *pdev)
 {
 	watchdog_unregister_device(&max63xx_wdt_dev);
 	return 0;
 }

 static 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,
 	.remove		= max63xx_wdt_remove,
 	.id_table	= max63xx_id_table,
 	.driver		= {
 		.name	= "max63xx_wdt",
 		.owner	= THIS_MODULE,
 	},
 };

 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");
	/*
	* 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/types.h>
	#include <linux/kernel.h>
	#include <linux/watchdog.h>
	#include <linux/init.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)

	static DEFINE_SPINLOCK(io_lock);

	static int nodelay;
	static void __iomem *wdt_base;

	/*
	* 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 {
	u8 wdset;
	u8 tdelay;
	u8 twd;
	};

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

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

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

	static struct max63xx_timeout *current_timeout;

	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)
	{
	u8 val;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);

	__raw_writeb(val \| MAX6369_WDI, wdt_base);
	__raw_writeb(val & ~MAX6369_WDI, wdt_base);

	spin_unlock(&io_lock);
	return 0;
	}

	static int max63xx_wdt_start(struct watchdog_device *wdd)
	{
	struct max63xx_timeout *entry = watchdog_get_drvdata(wdd);
	u8 val;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);
	val &= ~MAX6369_WDSET;
	val \|= entry->wdset;
	__raw_writeb(val, wdt_base);

	spin_unlock(&io_lock);

	/* check for a edge triggered startup */
	if (entry->tdelay == 0)
	max63xx_wdt_ping(wdd);
	return 0;
	}

	static int max63xx_wdt_stop(struct watchdog_device *wdd)
	{
	u8 val;

	spin_lock(&io_lock);

	val = __raw_readb(wdt_base);
	val &= ~MAX6369_WDSET;
	val \|= 3;
	__raw_writeb(val, wdt_base);

	spin_unlock(&io_lock);
	return 0;
	}

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

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

	static struct watchdog_device max63xx_wdt_dev = {
	.info = &max63xx_wdt_info,
	.ops = &max63xx_wdt_ops,
	};

	static int max63xx_wdt_probe(struct platform_device *pdev)
	{
	struct resource *wdt_mem;
	struct max63xx_timeout *table;

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

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

	dev_info(&pdev->dev, "requesting %ds heartbeat\n", heartbeat);
	current_timeout = max63xx_select_timeout(table, heartbeat);

	if (!current_timeout) {
	dev_err(&pdev->dev, "unable to satisfy heartbeat request\n");
	return -EINVAL;
	}

	dev_info(&pdev->dev, "using %ds heartbeat with %ds initial delay\n",
	current_timeout->twd, current_timeout->tdelay);

	heartbeat = current_timeout->twd;

	wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	wdt_base = devm_ioremap_resource(&pdev->dev, wdt_mem);
	if (IS_ERR(wdt_base))
	return PTR_ERR(wdt_base);

	max63xx_wdt_dev.timeout = heartbeat;
	watchdog_set_nowayout(&max63xx_wdt_dev, nowayout);
	watchdog_set_drvdata(&max63xx_wdt_dev, current_timeout);

	return watchdog_register_device(&max63xx_wdt_dev);
	}

	static int max63xx_wdt_remove(struct platform_device *pdev)
	{
	watchdog_unregister_device(&max63xx_wdt_dev);
	return 0;
	}

	static 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,
	.remove = max63xx_wdt_remove,
	.id_table = max63xx_id_table,
	.driver = {
	.name = "max63xx_wdt",
	.owner = THIS_MODULE,
	},
	};

	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");