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Commit 0400e313 authored by Wan ZongShun's avatar Wan ZongShun Committed by Wim Van Sebroeck
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[WATCHDOG] Add watchdog driver for NUC900 



Add watchdog device driver for the Nuvoton NUC900 series SoCs.

Signed-off-by: default avatarWan ZongShun <mcuos.com@gmail.com>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 3a5f9000

drivers/watchdog/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -266,6 +266,15 @@ config STMP3XXX_WATCHDOG 
	  To compile this driver as a module, choose M here: the

	  module will be called stmp3xxx_wdt.



config NUC900_WATCHDOG

	tristate "Nuvoton NUC900 watchdog"

	depends on ARCH_W90X900

	help

	  Say Y here if to include support for the watchdog timer

	  for the Nuvoton NUC900 series SoCs.

	  To compile this driver as a module, choose M here: the

	  module will be called nuc900_wdt.



# AVR32 Architecture



config AT32AP700X_WDT

drivers/watchdog/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ obj-$(CONFIG_DAVINCI_WATCHDOG) += davinci_wdt.o 
obj-$(CONFIG_ORION_WATCHDOG) += orion_wdt.o

obj-$(CONFIG_COH901327_WATCHDOG) += coh901327_wdt.o

obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o

obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o



# AVR32 Architecture

obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o

drivers/watchdog/nuc900_wdt.c

0 → 100644
+353 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2009 Nuvoton technology corporation.

 *

 * Wan ZongShun <mcuos.com@gmail.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation;version 2 of the License.

 *

 */



#include <linux/bitops.h>

#include <linux/errno.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/io.h>

#include <linux/clk.h>

#include <linux/kernel.h>

#include <linux/miscdevice.h>

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/platform_device.h>

#include <linux/interrupt.h>

#include <linux/types.h>

#include <linux/watchdog.h>

#include <linux/uaccess.h>



#define REG_WTCR		0x1c

#define WTCLK			(0x01 << 10)

#define WTE			(0x01 << 7)	/*wdt enable*/

#define WTIS			(0x03 << 4)

#define WTIF			(0x01 << 3)

#define WTRF			(0x01 << 2)

#define WTRE			(0x01 << 1)

#define WTR			(0x01 << 0)

/*

 * The watchdog time interval can be calculated via following formula:

 * WTIS		real time interval (formula)

 * 0x00		((2^ 14 ) * ((external crystal freq) / 256))seconds

 * 0x01		((2^ 16 ) * ((external crystal freq) / 256))seconds

 * 0x02		((2^ 18 ) * ((external crystal freq) / 256))seconds

 * 0x03		((2^ 20 ) * ((external crystal freq) / 256))seconds

 *

 * The external crystal freq is 15Mhz in the nuc900 evaluation board.

 * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds,

 * 0x03 = +- 16.92 seconds..

 */

#define WDT_HW_TIMEOUT		0x02

#define WDT_TIMEOUT		(HZ/2)

#define WDT_HEARTBEAT		15



static int heartbeat = WDT_HEARTBEAT;

module_param(heartbeat, int, 0);

MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "

	"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");



static int nowayout = WATCHDOG_NOWAYOUT;

module_param(nowayout, int, 0);

MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "

	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");



struct nuc900_wdt {

	struct resource  *res;

	struct clk	 *wdt_clock;

	struct platform_device *pdev;

	void __iomem	 *wdt_base;

	char		 expect_close;

	struct timer_list timer;

	spinlock_t       wdt_lock;

	unsigned long next_heartbeat;

};



static unsigned long nuc900wdt_busy;

struct nuc900_wdt *nuc900_wdt;



static inline void nuc900_wdt_keepalive(void)

{

	unsigned int val;



	spin_lock(&nuc900_wdt->wdt_lock);



	val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);

	val |= (WTR | WTIF);

	__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);



	spin_unlock(&nuc900_wdt->wdt_lock);

}



static inline void nuc900_wdt_start(void)

{

	unsigned int val;



	spin_lock(&nuc900_wdt->wdt_lock);



	val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);

	val |= (WTRE | WTE | WTR | WTCLK | WTIF);

	val &= ~WTIS;

	val |= (WDT_HW_TIMEOUT << 0x04);

	__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);



	spin_unlock(&nuc900_wdt->wdt_lock);



	nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;

	mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);

}



static inline void nuc900_wdt_stop(void)

{

	unsigned int val;



	del_timer(&nuc900_wdt->timer);



	spin_lock(&nuc900_wdt->wdt_lock);



	val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);

	val &= ~WTE;

	__raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);



	spin_unlock(&nuc900_wdt->wdt_lock);

}



static inline void nuc900_wdt_ping(void)

{

	nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;

}



static int nuc900_wdt_open(struct inode *inode, struct file *file)

{



	if (test_and_set_bit(0, &nuc900wdt_busy))

		return -EBUSY;



	nuc900_wdt_start();



	return nonseekable_open(inode, file);

}



static int nuc900_wdt_close(struct inode *inode, struct file *file)

{

	if (nuc900_wdt->expect_close == 42)

		nuc900_wdt_stop();

	else {

		dev_crit(&nuc900_wdt->pdev->dev,

			"Unexpected close, not stopping watchdog!\n");

		nuc900_wdt_ping();

	}



	nuc900_wdt->expect_close = 0;

	clear_bit(0, &nuc900wdt_busy);

	return 0;

}



static const struct watchdog_info nuc900_wdt_info = {

	.identity	= "nuc900 watchdog",

	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |

						WDIOF_MAGICCLOSE,

};



static long nuc900_wdt_ioctl(struct file *file,

					unsigned int cmd, unsigned long arg)

{

	void __user *argp = (void __user *)arg;

	int __user *p = argp;

	int new_value;



	switch (cmd) {

	case WDIOC_GETSUPPORT:

		return copy_to_user(argp, &nuc900_wdt_info,

				sizeof(nuc900_wdt_info)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:

	case WDIOC_GETBOOTSTATUS:

		return put_user(0, p);



	case WDIOC_KEEPALIVE:

		nuc900_wdt_ping();

		return 0;



	case WDIOC_SETTIMEOUT:

		if (get_user(new_value, p))

			return -EFAULT;



		heartbeat = new_value;

		nuc900_wdt_ping();



		return put_user(new_value, p);

	case WDIOC_GETTIMEOUT:

		return put_user(heartbeat, p);

	default:

		return -ENOTTY;

	}

}



static ssize_t nuc900_wdt_write(struct file *file, const char __user *data,

						size_t len, loff_t *ppos)

{

	if (!len)

		return 0;



	/* Scan for magic character */

	if (!nowayout) {

		size_t i;



		nuc900_wdt->expect_close = 0;



		for (i = 0; i < len; i++) {

			char c;

			if (get_user(c, data + i))

				return -EFAULT;

			if (c == 'V') {

				nuc900_wdt->expect_close = 42;

				break;

			}

		}

	}



	nuc900_wdt_ping();

	return len;

}



static void nuc900_wdt_timer_ping(unsigned long data)

{

	if (time_before(jiffies, nuc900_wdt->next_heartbeat)) {

		nuc900_wdt_keepalive();

		mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);

	} else

		dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n");

}



static const struct file_operations nuc900wdt_fops = {

	.owner		= THIS_MODULE,

	.llseek		= no_llseek,

	.unlocked_ioctl	= nuc900_wdt_ioctl,

	.open		= nuc900_wdt_open,

	.release	= nuc900_wdt_close,

	.write		= nuc900_wdt_write,

};



static struct miscdevice nuc900wdt_miscdev = {

	.minor		= WATCHDOG_MINOR,

	.name		= "watchdog",

	.fops		= &nuc900wdt_fops,

};



static int __devinit nuc900wdt_probe(struct platform_device *pdev)

{

	int ret = 0;



	nuc900_wdt = kzalloc(sizeof(struct nuc900_wdt), GFP_KERNEL);

	if (!nuc900_wdt)

		return -ENOMEM;



	nuc900_wdt->pdev = pdev;



	spin_lock_init(&nuc900_wdt->wdt_lock);



	nuc900_wdt->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (nuc900_wdt->res == NULL) {

		dev_err(&pdev->dev, "no memory resource specified\n");

		ret = -ENOENT;

		goto err_get;

	}



	if (!request_mem_region(nuc900_wdt->res->start,

				resource_size(nuc900_wdt->res), pdev->name)) {

		dev_err(&pdev->dev, "failed to get memory region\n");

		ret = -ENOENT;

		goto err_get;

	}



	nuc900_wdt->wdt_base = ioremap(nuc900_wdt->res->start,

					resource_size(nuc900_wdt->res));

	if (nuc900_wdt->wdt_base == NULL) {

		dev_err(&pdev->dev, "failed to ioremap() region\n");

		ret = -EINVAL;

		goto err_req;

	}



	nuc900_wdt->wdt_clock = clk_get(&pdev->dev, NULL);

	if (IS_ERR(nuc900_wdt->wdt_clock)) {

		dev_err(&pdev->dev, "failed to find watchdog clock source\n");

		ret = PTR_ERR(nuc900_wdt->wdt_clock);

		goto err_map;

	}



	clk_enable(nuc900_wdt->wdt_clock);



	setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0);



	if (misc_register(&nuc900wdt_miscdev)) {

		dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n",

			WATCHDOG_MINOR, ret);

		goto err_clk;

	}



	return 0;



err_clk:

	clk_disable(nuc900_wdt->wdt_clock);

	clk_put(nuc900_wdt->wdt_clock);

err_map:

	iounmap(nuc900_wdt->wdt_base);

err_req:

	release_mem_region(nuc900_wdt->res->start,

					resource_size(nuc900_wdt->res));

err_get:

	kfree(nuc900_wdt);

	return ret;

}



static int __devexit nuc900wdt_remove(struct platform_device *pdev)

{

	misc_deregister(&nuc900wdt_miscdev);



	clk_disable(nuc900_wdt->wdt_clock);

	clk_put(nuc900_wdt->wdt_clock);



	iounmap(nuc900_wdt->wdt_base);



	release_mem_region(nuc900_wdt->res->start,

					resource_size(nuc900_wdt->res));



	kfree(nuc900_wdt);



	return 0;

}



static struct platform_driver nuc900wdt_driver = {

	.probe		= nuc900wdt_probe,

	.remove		= __devexit_p(nuc900wdt_remove),

	.driver		= {

		.name	= "nuc900-wdt",

		.owner	= THIS_MODULE,

	},

};



static int __init nuc900_wdt_init(void)

{

	return platform_driver_register(&nuc900wdt_driver);

}



static void __exit nuc900_wdt_exit(void)

{

	platform_driver_unregister(&nuc900wdt_driver);

}



module_init(nuc900_wdt_init);

module_exit(nuc900_wdt_exit);



MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");

MODULE_DESCRIPTION("Watchdog driver for NUC900");

MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

MODULE_ALIAS("platform:nuc900-wdt");