260 lines
6.2 KiB
C
260 lines
6.2 KiB
C
/*
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* Driver for the MTX-1 Watchdog.
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*
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* (C) Copyright 2005 4G Systems <info@4g-systems.biz>,
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* All Rights Reserved.
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* http://www.4g-systems.biz
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*
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* (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Neither Michael Stickel nor 4G Systems admit liability nor provide
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* warranty for any of this software. This material is provided
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* "AS-IS" and at no charge.
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*
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* (c) Copyright 2005 4G Systems <info@4g-systems.biz>
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*
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* Release 0.01.
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* Author: Michael Stickel michael.stickel@4g-systems.biz
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*
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* Release 0.02.
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* Author: Florian Fainelli florian@openwrt.org
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* use the Linux watchdog/timer APIs
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*
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* The Watchdog is configured to reset the MTX-1
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* if it is not triggered for 100 seconds.
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* It should not be triggered more often than 1.6 seconds.
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*
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* A timer triggers the watchdog every 5 seconds, until
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* it is opened for the first time. After the first open
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* it MUST be triggered every 2..95 seconds.
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/miscdevice.h>
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#include <linux/fs.h>
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#include <linux/ioport.h>
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#include <linux/timer.h>
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#include <linux/completion.h>
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#include <linux/jiffies.h>
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#include <linux/watchdog.h>
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#include <linux/platform_device.h>
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#include <linux/io.h>
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#include <linux/uaccess.h>
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#include <linux/gpio.h>
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#include <asm/mach-au1x00/au1000.h>
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#define MTX1_WDT_INTERVAL (5 * HZ)
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static int ticks = 100 * HZ;
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static struct {
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struct completion stop;
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spinlock_t lock;
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int running;
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struct timer_list timer;
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int queue;
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int default_ticks;
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unsigned long inuse;
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unsigned gpio;
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unsigned int gstate;
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} mtx1_wdt_device;
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static void mtx1_wdt_trigger(unsigned long unused)
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{
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spin_lock(&mtx1_wdt_device.lock);
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if (mtx1_wdt_device.running)
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ticks--;
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/* toggle wdt gpio */
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mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
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gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
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if (mtx1_wdt_device.queue && ticks)
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mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
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else
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complete(&mtx1_wdt_device.stop);
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spin_unlock(&mtx1_wdt_device.lock);
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}
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static void mtx1_wdt_reset(void)
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{
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ticks = mtx1_wdt_device.default_ticks;
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}
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static void mtx1_wdt_start(void)
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{
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unsigned long flags;
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spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
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if (!mtx1_wdt_device.queue) {
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mtx1_wdt_device.queue = 1;
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mtx1_wdt_device.gstate = 1;
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gpio_set_value(mtx1_wdt_device.gpio, 1);
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mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
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}
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mtx1_wdt_device.running++;
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spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
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}
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static int mtx1_wdt_stop(void)
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{
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unsigned long flags;
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spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
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if (mtx1_wdt_device.queue) {
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mtx1_wdt_device.queue = 0;
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mtx1_wdt_device.gstate = 0;
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gpio_set_value(mtx1_wdt_device.gpio, 0);
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}
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ticks = mtx1_wdt_device.default_ticks;
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spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
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return 0;
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}
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/* Filesystem functions */
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static int mtx1_wdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
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return -EBUSY;
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return nonseekable_open(inode, file);
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}
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static int mtx1_wdt_release(struct inode *inode, struct file *file)
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{
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clear_bit(0, &mtx1_wdt_device.inuse);
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return 0;
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}
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static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = (int __user *)argp;
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unsigned int value;
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static const struct watchdog_info ident = {
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.options = WDIOF_CARDRESET,
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.identity = "MTX-1 WDT",
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};
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &ident, sizeof(ident)))
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return -EFAULT;
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break;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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put_user(0, p);
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break;
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case WDIOC_SETOPTIONS:
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if (get_user(value, p))
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return -EFAULT;
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if (value & WDIOS_ENABLECARD)
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mtx1_wdt_start();
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else if (value & WDIOS_DISABLECARD)
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mtx1_wdt_stop();
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else
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return -EINVAL;
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return 0;
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case WDIOC_KEEPALIVE:
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mtx1_wdt_reset();
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break;
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default:
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return -ENOTTY;
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}
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return 0;
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}
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static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
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size_t count, loff_t *ppos)
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{
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if (!count)
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return -EIO;
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mtx1_wdt_reset();
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return count;
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}
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static const struct file_operations mtx1_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.unlocked_ioctl = mtx1_wdt_ioctl,
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.open = mtx1_wdt_open,
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.write = mtx1_wdt_write,
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.release = mtx1_wdt_release,
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};
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static struct miscdevice mtx1_wdt_misc = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &mtx1_wdt_fops,
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};
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static int mtx1_wdt_probe(struct platform_device *pdev)
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{
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int ret;
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mtx1_wdt_device.gpio = pdev->resource[0].start;
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ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
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GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to request gpio");
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return ret;
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}
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spin_lock_init(&mtx1_wdt_device.lock);
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init_completion(&mtx1_wdt_device.stop);
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mtx1_wdt_device.queue = 0;
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clear_bit(0, &mtx1_wdt_device.inuse);
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setup_timer(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0L);
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mtx1_wdt_device.default_ticks = ticks;
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ret = misc_register(&mtx1_wdt_misc);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to register\n");
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return ret;
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}
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mtx1_wdt_start();
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dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
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return 0;
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}
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static int mtx1_wdt_remove(struct platform_device *pdev)
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{
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/* FIXME: do we need to lock this test ? */
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if (mtx1_wdt_device.queue) {
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mtx1_wdt_device.queue = 0;
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wait_for_completion(&mtx1_wdt_device.stop);
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}
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misc_deregister(&mtx1_wdt_misc);
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return 0;
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}
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static struct platform_driver mtx1_wdt_driver = {
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.probe = mtx1_wdt_probe,
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.remove = mtx1_wdt_remove,
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.driver.name = "mtx1-wdt",
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.driver.owner = THIS_MODULE,
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};
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module_platform_driver(mtx1_wdt_driver);
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MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
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MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:mtx1-wdt");
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