drivers/watchdog/ie6xx_wdt.c - kernel/common - Git at Google

 /*
  *      Intel Atom E6xx Watchdog driver
  *
  *      Copyright (C) 2011 Alexander Stein
  *                <[email protected]>
  *
  *      This program is free software; you can redistribute it and/or
  *      modify it under the terms of version 2 of the GNU General
  *      Public License as published by the Free Software Foundation.
  *
  *      This program is distributed in the hope that it will be
  *      useful, but WITHOUT ANY WARRANTY; without even the implied
  *      warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  *      PURPOSE.  See the GNU General Public License for more details.
  *      You should have received a copy of the GNU General Public
  *      License along with this program; if not, write to the Free
  *      Software Foundation, Inc., 59 Temple Place - Suite 330,
  *      Boston, MA  02111-1307, USA.
  *      The full GNU General Public License is included in this
  *      distribution in the file called COPYING.
  *
  */

 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/platform_device.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
 #include <linux/watchdog.h>
 #include <linux/seq_file.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/spinlock.h>

 #define DRIVER_NAME "ie6xx_wdt"

 #define PV1	0x00
 #define PV2	0x04

 #define RR0	0x0c
 #define RR1	0x0d
 #define WDT_RELOAD	0x01
 #define WDT_TOUT	0x02

 #define WDTCR	0x10
 #define WDT_PRE_SEL	0x04
 #define WDT_RESET_SEL	0x08
 #define WDT_RESET_EN	0x10
 #define WDT_TOUT_EN	0x20

 #define DCR	0x14

 #define WDTLR	0x18
 #define WDT_LOCK	0x01
 #define WDT_ENABLE	0x02
 #define WDT_TOUT_CNF	0x03

 #define MIN_TIME	1
 #define MAX_TIME	(10 * 60) /* 10 minutes */
 #define DEFAULT_TIME	60

 static unsigned int timeout = DEFAULT_TIME;
 module_param(timeout, uint, 0);
 MODULE_PARM_DESC(timeout,
 		"Default Watchdog timer setting ("
 		__MODULE_STRING(DEFAULT_TIME) "s)."
 		"The range is from 1 to 600");

 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) ")");

 static u8 resetmode = 0x10;
 module_param(resetmode, byte, 0);
 MODULE_PARM_DESC(resetmode,
 	"Resetmode bits: 0x08 warm reset (cold reset otherwise), "
 	"0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");

 static struct {
 	unsigned short sch_wdtba;
 	struct spinlock unlock_sequence;
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *debugfs;
 #endif
 } ie6xx_wdt_data;

 /*
  * This is needed to write to preload and reload registers
  * struct ie6xx_wdt_data.unlock_sequence must be used
  * to prevent sequence interrupts
  */
 static void ie6xx_wdt_unlock_registers(void)
 {
 	outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0);
 	outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0);
 }

 static int ie6xx_wdt_ping(struct watchdog_device *wdd)
 {
 	spin_lock(&ie6xx_wdt_data.unlock_sequence);
 	ie6xx_wdt_unlock_registers();
 	outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1);
 	spin_unlock(&ie6xx_wdt_data.unlock_sequence);
 	return 0;
 }

 static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 {
 	u32 preload;
 	u64 clock;
 	u8 wdtcr;

 	/* Watchdog clock is PCI Clock (33MHz) */
 	clock = 33000000;
 	/* and the preload value is loaded into [34:15] of the down counter */
 	preload = (t * clock) >> 15;
 	/*
 	 * Manual states preload must be one less.
 	 * Does not wrap as t is at least 1
 	 */
 	preload -= 1;

 	spin_lock(&ie6xx_wdt_data.unlock_sequence);

 	/* Set ResetMode & Enable prescaler for range 10ms to 10 min */
 	wdtcr = resetmode & 0x38;
 	outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR);

 	ie6xx_wdt_unlock_registers();
 	outl(0, ie6xx_wdt_data.sch_wdtba + PV1);

 	ie6xx_wdt_unlock_registers();
 	outl(preload, ie6xx_wdt_data.sch_wdtba + PV2);

 	ie6xx_wdt_unlock_registers();
 	outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1);

 	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

 	wdd->timeout = t;
 	return 0;
 }

 static int ie6xx_wdt_start(struct watchdog_device *wdd)
 {
 	ie6xx_wdt_set_timeout(wdd, wdd->timeout);

 	/* Enable the watchdog timer */
 	spin_lock(&ie6xx_wdt_data.unlock_sequence);
 	outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR);
 	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

 	return 0;
 }

 static int ie6xx_wdt_stop(struct watchdog_device *wdd)
 {
 	if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK)
 		return -1;

 	/* Disable the watchdog timer */
 	spin_lock(&ie6xx_wdt_data.unlock_sequence);
 	outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR);
 	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

 	return 0;
 }

 static const struct watchdog_info ie6xx_wdt_info = {
 	.identity =	"Intel Atom E6xx Watchdog",
 	.options =	WDIOF_SETTIMEOUT |
 			WDIOF_MAGICCLOSE |
 			WDIOF_KEEPALIVEPING,
 };

 static const struct watchdog_ops ie6xx_wdt_ops = {
 	.owner =	THIS_MODULE,
 	.start =	ie6xx_wdt_start,
 	.stop =		ie6xx_wdt_stop,
 	.ping =		ie6xx_wdt_ping,
 	.set_timeout =	ie6xx_wdt_set_timeout,
 };

 static struct watchdog_device ie6xx_wdt_dev = {
 	.info =		&ie6xx_wdt_info,
 	.ops =		&ie6xx_wdt_ops,
 	.min_timeout =	MIN_TIME,
 	.max_timeout =	MAX_TIME,
 };

 #ifdef CONFIG_DEBUG_FS

 static int ie6xx_wdt_show(struct seq_file *s, void *unused)
 {
 	seq_printf(s, "PV1   = 0x%08x\n",
 		inl(ie6xx_wdt_data.sch_wdtba + PV1));
 	seq_printf(s, "PV2   = 0x%08x\n",
 		inl(ie6xx_wdt_data.sch_wdtba + PV2));
 	seq_printf(s, "RR    = 0x%08x\n",
 		inw(ie6xx_wdt_data.sch_wdtba + RR0));
 	seq_printf(s, "WDTCR = 0x%08x\n",
 		inw(ie6xx_wdt_data.sch_wdtba + WDTCR));
 	seq_printf(s, "DCR   = 0x%08x\n",
 		inl(ie6xx_wdt_data.sch_wdtba + DCR));
 	seq_printf(s, "WDTLR = 0x%08x\n",
 		inw(ie6xx_wdt_data.sch_wdtba + WDTLR));

 	seq_printf(s, "\n");
 	return 0;
 }

 DEFINE_SHOW_ATTRIBUTE(ie6xx_wdt);

 static void ie6xx_wdt_debugfs_init(void)
 {
 	/* /sys/kernel/debug/ie6xx_wdt */
 	ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt",
 		S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_fops);
 }

 static void ie6xx_wdt_debugfs_exit(void)
 {
 	debugfs_remove(ie6xx_wdt_data.debugfs);
 }

 #else
 static void ie6xx_wdt_debugfs_init(void)
 {
 }

 static void ie6xx_wdt_debugfs_exit(void)
 {
 }
 #endif

 static int ie6xx_wdt_probe(struct platform_device *pdev)
 {
 	struct resource *res;
 	u8 wdtlr;
 	int ret;

 	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 	if (!res)
 		return -ENODEV;

 	if (!request_region(res->start, resource_size(res), pdev->name)) {
 		dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n",
 			(u64)res->start);
 		return -EBUSY;
 	}

 	ie6xx_wdt_data.sch_wdtba = res->start;
 	dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba);

 	ie6xx_wdt_dev.timeout = timeout;
 	watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout);
 	ie6xx_wdt_dev.parent = &pdev->dev;

 	spin_lock_init(&ie6xx_wdt_data.unlock_sequence);

 	wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR);
 	if (wdtlr & WDT_LOCK)
 		dev_warn(&pdev->dev,
 			"Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr);

 	ie6xx_wdt_debugfs_init();

 	ret = watchdog_register_device(&ie6xx_wdt_dev);
 	if (ret) {
 		dev_err(&pdev->dev,
 			"Watchdog timer: cannot register device (err =%d)\n",
 									ret);
 		goto misc_register_error;
 	}

 	return 0;

 misc_register_error:
 	ie6xx_wdt_debugfs_exit();
 	release_region(res->start, resource_size(res));
 	ie6xx_wdt_data.sch_wdtba = 0;
 	return ret;
 }

 static int ie6xx_wdt_remove(struct platform_device *pdev)
 {
 	struct resource *res;

 	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 	ie6xx_wdt_stop(NULL);
 	watchdog_unregister_device(&ie6xx_wdt_dev);
 	ie6xx_wdt_debugfs_exit();
 	release_region(res->start, resource_size(res));
 	ie6xx_wdt_data.sch_wdtba = 0;

 	return 0;
 }

 static struct platform_driver ie6xx_wdt_driver = {
 	.probe		= ie6xx_wdt_probe,
 	.remove		= ie6xx_wdt_remove,
 	.driver		= {
 		.name	= DRIVER_NAME,
 	},
 };

 static int __init ie6xx_wdt_init(void)
 {
 	/* Check boot parameters to verify that their initial values */
 	/* are in range. */
 	if ((timeout < MIN_TIME) ||
 	    (timeout > MAX_TIME)) {
 		pr_err("Watchdog timer: value of timeout %d (dec) "
 		  "is out of range from %d to %d (dec)\n",
 		  timeout, MIN_TIME, MAX_TIME);
 		return -EINVAL;
 	}

 	return platform_driver_register(&ie6xx_wdt_driver);
 }

 static void __exit ie6xx_wdt_exit(void)
 {
 	platform_driver_unregister(&ie6xx_wdt_driver);
 }

 late_initcall(ie6xx_wdt_init);
 module_exit(ie6xx_wdt_exit);

 MODULE_AUTHOR("Alexander Stein <[email protected]>");
 MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS("platform:" DRIVER_NAME);
	/*
	* Intel Atom E6xx Watchdog driver
	*
	* Copyright (C) 2011 Alexander Stein
	* <[email protected]>
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of version 2 of the GNU General
	* Public License as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be
	* useful, but WITHOUT ANY WARRANTY; without even the implied
	* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
	* PURPOSE. See the GNU General Public License for more details.
	* You should have received a copy of the GNU General Public
	* License along with this program; if not, write to the Free
	* Software Foundation, Inc., 59 Temple Place - Suite 330,
	* Boston, MA 02111-1307, USA.
	* The full GNU General Public License is included in this
	* distribution in the file called COPYING.
	*
	*/

	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/platform_device.h>
	#include <linux/io.h>
	#include <linux/kernel.h>
	#include <linux/types.h>
	#include <linux/watchdog.h>
	#include <linux/seq_file.h>
	#include <linux/debugfs.h>
	#include <linux/uaccess.h>
	#include <linux/spinlock.h>

	#define DRIVER_NAME "ie6xx_wdt"

	#define PV1 0x00
	#define PV2 0x04

	#define RR0 0x0c
	#define RR1 0x0d
	#define WDT_RELOAD 0x01
	#define WDT_TOUT 0x02

	#define WDTCR 0x10
	#define WDT_PRE_SEL 0x04
	#define WDT_RESET_SEL 0x08
	#define WDT_RESET_EN 0x10
	#define WDT_TOUT_EN 0x20

	#define DCR 0x14

	#define WDTLR 0x18
	#define WDT_LOCK 0x01
	#define WDT_ENABLE 0x02
	#define WDT_TOUT_CNF 0x03

	#define MIN_TIME 1
	#define MAX_TIME (10 * 60) /* 10 minutes */
	#define DEFAULT_TIME 60

	static unsigned int timeout = DEFAULT_TIME;
	module_param(timeout, uint, 0);
	MODULE_PARM_DESC(timeout,
	"Default Watchdog timer setting ("
	__MODULE_STRING(DEFAULT_TIME) "s)."
	"The range is from 1 to 600");

	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) ")");

	static u8 resetmode = 0x10;
	module_param(resetmode, byte, 0);
	MODULE_PARM_DESC(resetmode,
	"Resetmode bits: 0x08 warm reset (cold reset otherwise), "
	"0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");

	static struct {
	unsigned short sch_wdtba;
	struct spinlock unlock_sequence;
	#ifdef CONFIG_DEBUG_FS
	struct dentry *debugfs;
	#endif
	} ie6xx_wdt_data;

	/*
	* This is needed to write to preload and reload registers
	* struct ie6xx_wdt_data.unlock_sequence must be used
	* to prevent sequence interrupts
	*/
	static void ie6xx_wdt_unlock_registers(void)
	{
	outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0);
	outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0);
	}

	static int ie6xx_wdt_ping(struct watchdog_device *wdd)
	{
	spin_lock(&ie6xx_wdt_data.unlock_sequence);
	ie6xx_wdt_unlock_registers();
	outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1);
	spin_unlock(&ie6xx_wdt_data.unlock_sequence);
	return 0;
	}

	static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
	{
	u32 preload;
	u64 clock;
	u8 wdtcr;

	/* Watchdog clock is PCI Clock (33MHz) */
	clock = 33000000;
	/* and the preload value is loaded into [34:15] of the down counter */
	preload = (t * clock) >> 15;
	/*
	* Manual states preload must be one less.
	* Does not wrap as t is at least 1
	*/
	preload -= 1;

	spin_lock(&ie6xx_wdt_data.unlock_sequence);

	/* Set ResetMode & Enable prescaler for range 10ms to 10 min */
	wdtcr = resetmode & 0x38;
	outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR);

	ie6xx_wdt_unlock_registers();
	outl(0, ie6xx_wdt_data.sch_wdtba + PV1);

	ie6xx_wdt_unlock_registers();
	outl(preload, ie6xx_wdt_data.sch_wdtba + PV2);

	ie6xx_wdt_unlock_registers();
	outb(WDT_RELOAD \| WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1);

	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

	wdd->timeout = t;
	return 0;
	}

	static int ie6xx_wdt_start(struct watchdog_device *wdd)
	{
	ie6xx_wdt_set_timeout(wdd, wdd->timeout);

	/* Enable the watchdog timer */
	spin_lock(&ie6xx_wdt_data.unlock_sequence);
	outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR);
	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

	return 0;
	}

	static int ie6xx_wdt_stop(struct watchdog_device *wdd)
	{
	if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK)
	return -1;

	/* Disable the watchdog timer */
	spin_lock(&ie6xx_wdt_data.unlock_sequence);
	outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR);
	spin_unlock(&ie6xx_wdt_data.unlock_sequence);

	return 0;
	}

	static const struct watchdog_info ie6xx_wdt_info = {
	.identity = "Intel Atom E6xx Watchdog",
	.options = WDIOF_SETTIMEOUT \|
	WDIOF_MAGICCLOSE \|
	WDIOF_KEEPALIVEPING,
	};

	static const struct watchdog_ops ie6xx_wdt_ops = {
	.owner = THIS_MODULE,
	.start = ie6xx_wdt_start,
	.stop = ie6xx_wdt_stop,
	.ping = ie6xx_wdt_ping,
	.set_timeout = ie6xx_wdt_set_timeout,
	};

	static struct watchdog_device ie6xx_wdt_dev = {
	.info = &ie6xx_wdt_info,
	.ops = &ie6xx_wdt_ops,
	.min_timeout = MIN_TIME,
	.max_timeout = MAX_TIME,
	};

	#ifdef CONFIG_DEBUG_FS

	static int ie6xx_wdt_show(struct seq_file s, void unused)
	{
	seq_printf(s, "PV1 = 0x%08x\n",
	inl(ie6xx_wdt_data.sch_wdtba + PV1));
	seq_printf(s, "PV2 = 0x%08x\n",
	inl(ie6xx_wdt_data.sch_wdtba + PV2));
	seq_printf(s, "RR = 0x%08x\n",
	inw(ie6xx_wdt_data.sch_wdtba + RR0));
	seq_printf(s, "WDTCR = 0x%08x\n",
	inw(ie6xx_wdt_data.sch_wdtba + WDTCR));
	seq_printf(s, "DCR = 0x%08x\n",
	inl(ie6xx_wdt_data.sch_wdtba + DCR));
	seq_printf(s, "WDTLR = 0x%08x\n",
	inw(ie6xx_wdt_data.sch_wdtba + WDTLR));

	seq_printf(s, "\n");
	return 0;
	}

	DEFINE_SHOW_ATTRIBUTE(ie6xx_wdt);

	static void ie6xx_wdt_debugfs_init(void)
	{
	/* /sys/kernel/debug/ie6xx_wdt */
	ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt",
	S_IFREG \| S_IRUGO, NULL, NULL, &ie6xx_wdt_fops);
	}

	static void ie6xx_wdt_debugfs_exit(void)
	{
	debugfs_remove(ie6xx_wdt_data.debugfs);
	}

	#else
	static void ie6xx_wdt_debugfs_init(void)
	{
	}

	static void ie6xx_wdt_debugfs_exit(void)
	{
	}
	#endif

	static int ie6xx_wdt_probe(struct platform_device *pdev)
	{
	struct resource *res;
	u8 wdtlr;
	int ret;

	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
	if (!res)
	return -ENODEV;

	if (!request_region(res->start, resource_size(res), pdev->name)) {
	dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n",
	(u64)res->start);
	return -EBUSY;
	}

	ie6xx_wdt_data.sch_wdtba = res->start;
	dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba);

	ie6xx_wdt_dev.timeout = timeout;
	watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout);
	ie6xx_wdt_dev.parent = &pdev->dev;

	spin_lock_init(&ie6xx_wdt_data.unlock_sequence);

	wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR);
	if (wdtlr & WDT_LOCK)
	dev_warn(&pdev->dev,
	"Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr);

	ie6xx_wdt_debugfs_init();

	ret = watchdog_register_device(&ie6xx_wdt_dev);
	if (ret) {
	dev_err(&pdev->dev,
	"Watchdog timer: cannot register device (err =%d)\n",
	ret);
	goto misc_register_error;
	}

	return 0;

	misc_register_error:
	ie6xx_wdt_debugfs_exit();
	release_region(res->start, resource_size(res));
	ie6xx_wdt_data.sch_wdtba = 0;
	return ret;
	}

	static int ie6xx_wdt_remove(struct platform_device *pdev)
	{
	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
	ie6xx_wdt_stop(NULL);
	watchdog_unregister_device(&ie6xx_wdt_dev);
	ie6xx_wdt_debugfs_exit();
	release_region(res->start, resource_size(res));
	ie6xx_wdt_data.sch_wdtba = 0;

	return 0;
	}

	static struct platform_driver ie6xx_wdt_driver = {
	.probe = ie6xx_wdt_probe,
	.remove = ie6xx_wdt_remove,
	.driver = {
	.name = DRIVER_NAME,
	},
	};

	static int __init ie6xx_wdt_init(void)
	{
	/* Check boot parameters to verify that their initial values */
	/* are in range. */
	if ((timeout < MIN_TIME) \|\|
	(timeout > MAX_TIME)) {
	pr_err("Watchdog timer: value of timeout %d (dec) "
	"is out of range from %d to %d (dec)\n",
	timeout, MIN_TIME, MAX_TIME);
	return -EINVAL;
	}

	return platform_driver_register(&ie6xx_wdt_driver);
	}

	static void __exit ie6xx_wdt_exit(void)
	{
	platform_driver_unregister(&ie6xx_wdt_driver);
	}

	late_initcall(ie6xx_wdt_init);
	module_exit(ie6xx_wdt_exit);

	MODULE_AUTHOR("Alexander Stein <[email protected]>");
	MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
	MODULE_LICENSE("GPL");
	MODULE_ALIAS("platform:" DRIVER_NAME);