Message-ID: <20071007070832.GA13090@pazke.donpac.ru>
Date:	Sun, 7 Oct 2007 11:08:32 +0400
From:	Andrey Panin <pazke@...pac.ru>
To:	Gilles Gigan <gilles.gigan@...ebottle.com>
Cc:	LKML <linux-kernel@...r.kernel.org>, wim@...ana.be
Subject: Re: [PATCH] watchdog: add Nano 7240 driver

On 280, 10 07, 2007 at 01:39:28AM +1000, Gilles Gigan wrote:
> from: Gilles Gigan <gilles.gigan@...ebottle.com>
>
> Adds watchdog driver for EPIC Nano 7240 boards from IEI
>
> Signed-off-by: Gilles Gigan <gilles.gigan@...ebottle.com>
> ---
>
> diff -uprN -X linux-2.6.23-rc9/Documentation/dontdiff 
> linux-2.6.23-rc9/drivers/char/watchdog/Kconfig
> linux-2.6.23-rc9-dirty/drivers/char/watchdog/Kconfig
> --- linux-2.6.23-rc9/drivers/char/watchdog/Kconfig	2007-10-06 
> 01:43:44.000000000 +1000
> +++ linux-2.6.23-rc9-dirty/drivers/char/watchdog/Kconfig	2007-10-06 
> 14:49:03.000000000 +1000
> @@ -455,6 +455,19 @@ config SBC8360_WDT
>
>   	  Most people will say N.
>
> +config SBC7240_WDT
> +	tristate "SBC Nano 7240 Watchdog Timer"
> +	depends on X86_32
> +	---help---
> +	  This is the driver for the hardware watchdog found on the IEI
> +	  single board computers EPIC Nano 7240 (and likely others). This
> +	  watchdog simply watches your kernel to make sure it doesn't freeze,
> +	  and if it does, it reboots your computer after a certain amount of
> +	  time.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called sbc7240_wdt.
> +
>   config CPU5_WDT
>   	tristate "SMA CPU5 Watchdog"
>   	depends on X86
> diff -uprN -X linux-2.6.23-rc9/Documentation/dontdiff
> linux-2.6.23-rc9/drivers/char/watchdog/Makefile 
> linux-2.6.23-rc9-dirty/drivers/char/watchdog/Makefile
> --- linux-2.6.23-rc9/drivers/char/watchdog/Makefile	2007-10-06 
> 01:43:44.000000000 +1000
> +++ linux-2.6.23-rc9-dirty/drivers/char/watchdog/Makefile	2007-10-06 
> 14:49:03.000000000 +1000
> @@ -71,6 +71,7 @@ obj-$(CONFIG_SCx200_WDT) += scx200_wdt.o
>   obj-$(CONFIG_PC87413_WDT) += pc87413_wdt.o
>   obj-$(CONFIG_60XX_WDT) += sbc60xxwdt.o
>   obj-$(CONFIG_SBC8360_WDT) += sbc8360.o
> +obj-$(CONFIG_SBC7240_WDT) += sbc7240.o
>   obj-$(CONFIG_CPU5_WDT) += cpu5wdt.o
>   obj-$(CONFIG_SMSC37B787_WDT) += smsc37b787_wdt.o
>   obj-$(CONFIG_W83627HF_WDT) += w83627hf_wdt.o
> diff -uprN -X linux-2.6.23-rc9/Documentation/dontdiff
> linux-2.6.23-rc9/drivers/char/watchdog/sbc7240_wdt.c
> linux-2.6.23-rc9-dirty/drivers/char/watchdog/sbc7240_wdt.c
> --- linux-2.6.23-rc9/drivers/char/watchdog/sbc7240_wdt.c	1970-01-01 
> 10:00:00.000000000 +1000
> +++ linux-2.6.23-rc9-dirty/drivers/char/watchdog/sbc7240_wdt.c	2007-10-06 
> 16:54:52.000000000 +1000
> @@ -0,0 +1,311 @@
> +/*
> + *	NANO7240 SBC Watchdog device driver
> + *
> + *	Based on w83877f.c by Scott Jennings,
> + *
> + *	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;
> + *
> + *	Software distributed under the License is distributed on an "AS IS"
> + *	basis, WITHOUT WARRANTY OF ANY KIND, either express or
> + *	implied. See the License for the specific language governing
> + *	rights and limitations under the License.
> + *
> + *	(c) Copyright 2007  Gilles GIGAN <gilles.gigan at jcu.edu.au>
> + *
> + *      10/01- 2007   [Initial revision]
> + */
> +
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/types.h>
> +#include <linux/jiffies.h>
> +#include <linux/miscdevice.h>
> +#include <linux/watchdog.h>
> +#include <linux/fs.h>
> +#include <linux/ioport.h>
> +#include <linux/notifier.h>
> +#include <linux/reboot.h>
> +#include <linux/init.h>
> +#include <asm/io.h>
> +#include <asm/uaccess.h>
> +#include <asm/system.h>
> +#include <asm/atomic.h>
> +
> +#define PREFIX "sbc7240_wdt: "
> +
> +#define ENABLE_SBC7240_PORT 		0x443
> +#define DISABLE_SBC7240_PORT 		0x043
> +#define SET_TIMEOUT_SBC7240_PORT 	ENABLE_SBC7240_PORT
> +#define WDT_MAGIC_CHAR			'V'
> +
> +#define WATCHDOG_TIMEOUT 		30	/* 30 sec default timeout */
> +#define WATCHDOG_MAX_TIMEOUT 		255
> +static int timeout = WATCHDOG_TIMEOUT;	/* in seconds */
> +module_param(timeout, int, 0);
> +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
> +		 __MODULE_STRING(WATCHDOG_MAX_TIMEOUT) ", default="
> +		 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
> +
> +#ifdef CONFIG_WATCHDOG_NOWAYOUT
> +#define NOWAYOUT			1
> +#else
> +#define NOWAYOUT			0
> +#endif
> +static int nowayout = NOWAYOUT;

You don't need this #ifdef crap. Just use WATCHDOG_NOWAYOUT instead.

> +module_param(nowayout, int, 0);
> +MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
> +
> +#define OPEN_STATUS_BIT			0
> +#define ENABLED_STATUS_BIT		1
> +static unsigned long wdt_status;
> +
> +/*
> + * Utility routines
> + */
> +
> +static void wdt_disable(void)
> +{
> +	/* disable the watchdog */
> +	if (test_and_clear_bit(ENABLED_STATUS_BIT, &wdt_status)) {
> +		inb_p(DISABLE_SBC7240_PORT);
> +		printk(KERN_INFO PREFIX "Watchdog timer is now disabled.\n");
> +	}
> +}
> +
> +static void wdt_enable(void)
> +{
> +	/* enable the watchdog */
> +	if (!test_and_set_bit(ENABLED_STATUS_BIT, &wdt_status)) {
> +		inb_p(ENABLE_SBC7240_PORT);
> +		printk(KERN_INFO PREFIX "Watchdog timer is now enabled.\n");
> +	}
> +}
> +
> +static int wdt_set_timeout(int t)
> +{
> +	if (t < 1 || t > WATCHDOG_MAX_TIMEOUT) {
> +		printk(KERN_ERR PREFIX "timeout value must be 1<=x<=%d\n",
> +		       WATCHDOG_MAX_TIMEOUT);
> +		return -1;
> +	}
> +	/* set the timeout */
> +	outb_p((unsigned)t, ENABLE_SBC7240_PORT);
> +	printk(KERN_INFO PREFIX "timeout set to %d seconds\n", t);
> +	return 0;
> +}
> +
> +/* Whack the dog */
> +static inline void wdt_keepalive(void)
> +{
> +	if (test_bit(ENABLED_STATUS_BIT, &wdt_status))
> +		inb_p(ENABLE_SBC7240_PORT);
> +}
> +
> +/*
> + * /dev/watchdog handling
> + */
> +static ssize_t fop_write(struct file *file, const char __user * buf,
> +			 size_t count, loff_t * ppos)
> +{
> +	size_t i;
> +	char c;
> +	int got_magic_char = 0;
> +
> +	/* is there a magic char ? */
> +	for (i = 0; i != count; i++) {
> +		if (get_user(c, buf + i))
> +			return -EFAULT;
> +		if (c == WDT_MAGIC_CHAR) {
> +			got_magic_char = 1;
> +			break;
> +		}
> +	}
> +
> +	if (got_magic_char)
> +		wdt_disable();
> +	else
> +		wdt_keepalive();
> +
> +	return count;
> +}
> +
> +static int fop_open(struct inode *inode, struct file *file)
> +{
> +	if (test_and_set_bit(OPEN_STATUS_BIT, &wdt_status))
> +		return -EBUSY;
> +
> +	return nonseekable_open(inode, file);
> +}
> +
> +static int fop_close(struct inode *inode, struct file *file)
> +{
> +	if (!nowayout)
> +		wdt_disable();
> +
> +	clear_bit(OPEN_STATUS_BIT, &wdt_status);
> +	return 0;
> +}
> +
> +static int fop_ioctl(struct inode *inode, struct file *file, unsigned int 
> cmd,
> +		     unsigned long arg)
> +{
> +	static struct watchdog_info ident = {
> +		.options =
> +		    WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
> +		.firmware_version = 1,
> +		.identity = "SBC7240",
> +	};
> +
> +	if ((_IOC_DIR(cmd) & _IOC_READ) &&
> +	    (!access_ok(VERIFY_WRITE, (void __user *)arg, _IOC_SIZE(cmd))))
> +		return -EFAULT;
> +	if ((_IOC_DIR(cmd) & _IOC_WRITE) &&
> +	    (!access_ok(VERIFY_READ, (void __user *)arg, _IOC_SIZE(cmd))))
> +		return -EFAULT;

Is this really needed ?

> +	switch (cmd) {
> +	case WDIOC_GETSUPPORT:
> +		return __copy_to_user((void __user *)arg,
> +				      &ident, sizeof(ident)) ? -EFAULT : 0;
> +	case WDIOC_GETSTATUS:
> +	case WDIOC_GETBOOTSTATUS:
> +		return __put_user(0, (int __user *)arg);
> +	case WDIOC_KEEPALIVE:
> +		wdt_keepalive();
> +		return 0;
> +	case WDIOC_SETOPTIONS:{
> +			int retval = -EINVAL;
> +
> +			if (arg & WDIOS_DISABLECARD) {
> +				wdt_disable();
> +				retval = 0;
> +			}
> +
> +			if (arg & WDIOS_ENABLECARD) {
> +				wdt_enable();
> +				retval = 0;
> +			}
> +
> +			return retval;
> +		}
> +	case WDIOC_SETTIMEOUT:{
> +			int new_timeout;
> +
> +			if (__get_user(new_timeout, (int __user *)arg))
> +				return -EFAULT;
> +
> +			if (wdt_set_timeout(new_timeout))
> +				return -EINVAL;
> +
> +			timeout = new_timeout;
> +			return 0;
> +		}
> +	case WDIOC_GETTIMEOUT:
> +		return __put_user(timeout, (int __user *)arg);
> +	default:
> +		return -ENOTTY;
> +	}
> +}
> +
> +static const struct file_operations wdt_fops = {
> +	.owner = THIS_MODULE,
> +	.llseek = no_llseek,
> +	.write = fop_write,
> +	.open = fop_open,
> +	.release = fop_close,
> +	.ioctl = fop_ioctl,
> +};
> +
> +static struct miscdevice wdt_miscdev = {
> +	.minor = WATCHDOG_MINOR,
> +	.name = "watchdog",
> +	.fops = &wdt_fops,
> +};
> +
> +/*
> + *	Notifier for system down
> + */
> +
> +static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
> +			  void *unused)
> +{
> +	if (code == SYS_DOWN || code == SYS_HALT)
> +		wdt_disable();
> +	return NOTIFY_DONE;
> +}
> +
> +static struct notifier_block wdt_notifier = {
> +	.notifier_call = wdt_notify_sys,
> +};
> +
> +static void __exit sbc7240_wdt_unload(void)
> +{
> +	printk(KERN_INFO PREFIX "Removing watchdog\n");
> +	misc_deregister(&wdt_miscdev);
> +
> +	unregister_reboot_notifier(&wdt_notifier);
> +	release_region(ENABLE_SBC7240_PORT, 1);
> +}
> +
> +static int __init sbc7240_wdt_init(void)
> +{
> +	int rc = -EBUSY;
> +
> +	if (!request_region(ENABLE_SBC7240_PORT, 1, "SBC7240 WDT")) {
> +		printk(KERN_ERR PREFIX "I/O address 0x%04x already in use\n",
> +		       ENABLE_SBC7240_PORT);
> +		rc = -EIO;
> +		goto err_out;
> +	}
> +
> +	/* The IO port 0x043 used to disable the watchdog
> +	 * is already claimed by the system timer, so we
> +	 * cant request_region() it ...*/
> +
> +	rc = misc_register(&wdt_miscdev);
> +	if (rc) {
> +		printk(KERN_ERR PREFIX
> +		       "cannot register miscdev on minor=%d (err=%d)\n",
> +		       wdt_miscdev.minor, rc);
> +		goto err_out_region1;
> +	}
> +
> +	rc = register_reboot_notifier(&wdt_notifier);
> +	if (rc) {
> +		printk(KERN_ERR PREFIX
> +		       "cannot register reboot notifier (err=%d)\n", rc);
> +		goto err_out_miscdev;
> +	}
> +
> +	if (timeout < 1 || timeout > WATCHDOG_MAX_TIMEOUT) {
> +		timeout = WATCHDOG_TIMEOUT;
> +		printk(KERN_INFO PREFIX
> +		       "timeout value must be 1<=x<=%d, using %d\n",
> +		       WATCHDOG_MAX_TIMEOUT, timeout);
> +	}
> +	wdt_set_timeout(timeout);
> +
> +	printk(KERN_INFO PREFIX
> +	       "Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
> +	       nowayout);
> +
> +	return 0;
> +
> +      err_out_miscdev:
> +	misc_deregister(&wdt_miscdev);
> +      err_out_region1:
> +	release_region(ENABLE_SBC7240_PORT, 1);
> +      err_out:
> +	return rc;
> +}
> +
> +module_init(sbc7240_wdt_init);
> +module_exit(sbc7240_wdt_unload);
> +
> +MODULE_AUTHOR("Gilles Gigan");
> +MODULE_DESCRIPTION
> +    ("Watchdog device driver for single board computer EPIC Nano 7240 from 
> iEi");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
>
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-- 
Andrey Panin		| Linux and UNIX system administrator
pazke@...pac.ru		| PGP key: wwwkeys.pgp.net

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