Re: [PATCH][DRIVER][RFC] CPU5 watchdog driver for 2.5

From: Rusty Lynch (rusty@linux.co.intel.com)
Date: Mon Feb 10 2003 - 23:38:14 EST


On Tue, 2003-02-11 at 04:26, Heiko Ronsdorf wrote:
> Rusty Lynch schrieb am Mon, Feb 10, 2003 at 02:33:27PM -0800:
<snip>
> > * I'm pretty sure that in general adding new code to /proc (that has
> > nothing to do with processes) is frowned on.
>
> I don't know how to track the watchdog. Suggestions are welcome.
>
> Heiko
>

I CC'ed Patrick Mochel to get his opinion on this, but if I am
interpreting the new driver model documentation correctly, then it would
be appropriate to make an IO controlled watchdog timer a
"platform_device". That will let user space see your device in sysfs as
$YOUR_SYSFS_ROOT/devices/legacy/watchdog0/, and then you can use
device_create_file() to add a new file inside the the watchdog0
directory.

Here is your cpu5wdt.c file with the procfs stuff replaced with code
that adds an embedded platform_device to your basic data structure,
registers the driver as a platform device, and then creates a file
called $YOUR_SYSFS_ROOT/devices/legacy/watchdog0/statistics that will
read the same as your original procfs file. (Or at least I think it
will. It at least compiles :->)

    --rustyl

/*
 * sma cpu5 watchdog driver
 *
 * Copyright (C) 2003 Heiko Ronsdorf <hero@ihg.uni-duisburg.de>
 *
 * 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; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/timer.h>
#include <asm/io.h>
#include <asm/uaccess.h>

#include <linux/watchdog.h>
#include <linux/kobject.h>
#include <linux/device.h>

/* adjustable parameters */

static int verbose = 0;
static int port = 0x91;
static volatile int ticks = 10000;

#define PFX "cpu5wdt: "

#define CPU5WDT_EXTENT 0x0A

#define CPU5WDT_STATUS_REG 0x00
#define CPU5WDT_TIME_A_REG 0x02
#define CPU5WDT_TIME_B_REG 0x03
#define CPU5WDT_MODE_REG 0x04
#define CPU5WDT_TRIGGER_REG 0x07
#define CPU5WDT_ENABLE_REG 0x08
#define CPU5WDT_RESET_REG 0x09

#define CPU5WDT_INTERVAL (HZ/10+1)

#define to_platform_device(n) container_of(n, struct platform_device, dev)
#define to_wdt_device(n) container_of(n, struct wdt_device, dev)

/* some device data */

struct wdt_device {
        struct semaphore stop;
        volatile int running;
        struct timer_list timer;
        volatile int queue;
        int default_ticks;
        int min_ticks;
        unsigned long inuse;
        struct platform_device dev;
};

static struct wdt_device cpu5wdt_device = {
        .dev = {
                .name = "watchdog",
                .id = 0,
                .dev = {
                        .name = "CPU5 Watchdog Device",
                },
        },
};

ssize_t statistics_show(struct device * dev, char * buf)
{
        size_t len;
        struct wdt_device *d = to_wdt_device(to_platform_device(dev));
        len = sprintf(buf, "activation: %i\n", d->queue);
        len += sprintf(buf+len, "status: %i\n", d->running);
        len += sprintf(buf+len, "current ticks: %i\n", ticks);
        len += sprintf(buf+len, "min ticks: %i\n", d->min_ticks);
        return len;

}
DEVICE_ATTR(statistics,S_IRUGO,statistics_show,NULL);

/* generic helper functions */

static void cpu5wdt_trigger(unsigned long unused)
{
        if ( verbose > 2 )
                printk(KERN_DEBUG PFX "trigger at %i ticks\n", ticks);

        if( cpu5wdt_device.running )
                ticks--;

        /* keep watchdog alive */
        outb(1, port + CPU5WDT_TRIGGER_REG);

        /* requeue?? */
        if( cpu5wdt_device.queue && ticks ) {
                cpu5wdt_device.timer.expires = jiffies + CPU5WDT_INTERVAL;
                add_timer(&cpu5wdt_device.timer);
        }
        else {
                /* ticks doesn't matter anyway */
                up(&cpu5wdt_device.stop);
        }

}

static void cpu5wdt_reset(void)
{
        if ( ticks < cpu5wdt_device.min_ticks )
                cpu5wdt_device.min_ticks = ticks;

        ticks = cpu5wdt_device.default_ticks;

        if ( verbose )
                printk(KERN_DEBUG PFX "reset (%i ticks)\n", (int) ticks);

}

static void cpu5wdt_start(void)
{
        if ( !cpu5wdt_device.queue ) {
                cpu5wdt_device.queue = 1;
                outb(0, port + CPU5WDT_TIME_A_REG);
                outb(0, port + CPU5WDT_TIME_B_REG);
                outb(1, port + CPU5WDT_MODE_REG);
                outb(0, port + CPU5WDT_RESET_REG);
                outb(0, port + CPU5WDT_ENABLE_REG);
                cpu5wdt_device.timer.expires = jiffies + CPU5WDT_INTERVAL;
                add_timer(&cpu5wdt_device.timer);
        }
        /* if process dies, counter is not decremented */
        cpu5wdt_device.running++;
}

static int cpu5wdt_stop(void)
{
        if ( cpu5wdt_device.running )
                cpu5wdt_device.running = 0;

        ticks = cpu5wdt_device.default_ticks;

        if ( verbose )
                printk(KERN_CRIT PFX "stop not possible\n");

        return -EIO;
}

/* filesystem operations */

static int cpu5wdt_open(struct inode *inode, struct file *file)
{
        switch(minor(inode->i_rdev)) {
                case WATCHDOG_MINOR:
                        if ( test_and_set_bit(0, &cpu5wdt_device.inuse) )
                                return -EBUSY;
                        break;
                default:
                        return -ENODEV;
        }
        return 0;

}

static int cpu5wdt_release(struct inode *inode, struct file *file)
{
        if(minor(inode->i_rdev)==WATCHDOG_MINOR) {
                clear_bit(0, &cpu5wdt_device.inuse);
        }
        return 0;
}

static int cpu5wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
        unsigned int value;
        static struct watchdog_info ident =
        {
                .options = WDIOF_CARDRESET,
                .identity = "CPU5 WDT"
        };
  
        switch(cmd) {
                case WDIOC_KEEPALIVE:
                        cpu5wdt_reset();
                        break;
                case WDIOC_GETSTATUS:
                        value = inb(port + CPU5WDT_STATUS_REG);
                        value = (value >> 2) & 1;
                        if ( copy_to_user((int *)arg, (int *)&value, sizeof(int)) )
                                return -EFAULT;
                        break;
                case WDIOC_GETSUPPORT:
                        if ( copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident)) )
                                return -EFAULT;
                        break;
                case WDIOC_SETOPTIONS:
                        if ( copy_from_user(&value, (int *)arg, sizeof(int)) )
                                return -EFAULT;
                        switch(value) {
                                case WDIOS_ENABLECARD:
                                        cpu5wdt_start();
                                        break;
                                case WDIOS_DISABLECARD:
                                        return cpu5wdt_stop();
                                default:
                                        return -EINVAL;
                        }
                        break;
                default:
                            return -EINVAL;
        }
        return 0;
}

static ssize_t cpu5wdt_write(struct file *file, const char *buf, size_t count, loff_t *ppos)
{
        if ( !count )
                return -EIO;
        
        cpu5wdt_reset();
        return count;

}

static struct file_operations cpu5wdt_fops = {
        .owner = THIS_MODULE,
        .ioctl = cpu5wdt_ioctl,
        .open = cpu5wdt_open,
        .write = cpu5wdt_write,
        .release = cpu5wdt_release,
};

static struct miscdevice cpu5wdt_misc = {
        .minor = WATCHDOG_MINOR,
        .name = "watchdog",
        .fops = &cpu5wdt_fops
};

/* init/exit function */

static int __devinit cpu5wdt_init(void)
{
        unsigned int val;
        int err;

        if ( verbose )
                printk(KERN_DEBUG PFX "port=0x%x, verbose=%i\n", port, verbose);

        if ( (err = misc_register(&cpu5wdt_misc)) < 0 ) {
                printk(KERN_ERR PFX "misc_register failed\n");
                goto no_misc;
        }

        if ( !request_region(port, CPU5WDT_EXTENT, PFX) ) {
                printk(KERN_ERR PFX "request_region failed\n");
                err = -EBUSY;
                goto no_port;
        }

        /* watchdog reboot? */
        val = inb(port + CPU5WDT_STATUS_REG);
        val = (val >> 2) & 1;
        if ( !val )
                printk(KERN_INFO PFX "sorry, was my fault\n");

        init_MUTEX_LOCKED(&cpu5wdt_device.stop);
        cpu5wdt_device.queue = 0;
        cpu5wdt_device.min_ticks = ticks;

        clear_bit(0, &cpu5wdt_device.inuse);

        platform_device_register(&cpu5wdt_device.dev);
        device_create_file(&cpu5wdt_device.dev.dev, &dev_attr_statistics);

        init_timer(&cpu5wdt_device.timer);
        cpu5wdt_device.timer.function = cpu5wdt_trigger;
        cpu5wdt_device.timer.data = 0;

        cpu5wdt_device.default_ticks = ticks;

        printk(KERN_INFO PFX "init success\n");

        return 0;

no_port:
        misc_deregister(&cpu5wdt_misc);
no_misc:
        return err;
}

static int __devinit cpu5wdt_init_module(void)
{
        return cpu5wdt_init();
}

static void __devexit cpu5wdt_exit(void)
{
        if ( cpu5wdt_device.queue ) {
                cpu5wdt_device.queue = 0;
                down(&cpu5wdt_device.stop);
        }

        platform_device_unregister(&cpu5wdt_device.dev);
        device_remove_file(&cpu5wdt_device.dev.dev, &dev_attr_statistics);
        misc_deregister(&cpu5wdt_misc);

        release_region(port, CPU5WDT_EXTENT);

}

static void __devexit cpu5wdt_exit_module(void)
{
        cpu5wdt_exit();
}

/* module entry points */

module_init(cpu5wdt_init_module);
module_exit(cpu5wdt_exit_module);

MODULE_AUTHOR("Heiko Ronsdorf <hero@ihg.uni-duisburg.de>");
MODULE_DESCRIPTION("sma cpu5 watchdog driver");
MODULE_SUPPORTED_DEVICE("sma cpu5 watchdog");
MODULE_LICENSE("GPL");

MODULE_PARM(port, "i");
MODULE_PARM_DESC(port, "base address of watchdog card, default is 0x91");

MODULE_PARM(verbose, "i");
MODULE_PARM_DESC(verbose, "be verbose, default is 0 (no)");

MODULE_PARM(ticks, "i");
MODULE_PARM_DESC(ticks, "count down ticks, default is 10000");

EXPORT_NO_SYMBOLS;

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This archive was generated by hypermail 2b29 : Sat Feb 15 2003 - 22:00:35 EST