patch-2.4.21 linux-2.4.21/drivers/char/scx200_wdt.c

• Lines: 278
• Date: 2003-06-13 07:51:33.000000000 -0700
• Orig file: linux-2.4.20/drivers/char/scx200_wdt.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.20/drivers/char/scx200_wdt.c linux-2.4.21/drivers/char/scx200_wdt.c
@@ -0,0 +1,277 @@
+/* linux/drivers/char/scx200_wdt.c 
+
+   National Semiconductor SCx200 Watchdog support
+
+   Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
+
+   Som code taken from:
+   National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
+   (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.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; either version 2 of the
+   License, or (at your option) any later version.
+
+   The author(s) of this software shall not be held liable for damages
+   of any nature resulting due to the use of this software. This
+   software is provided AS-IS with no warranties. */
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/pci.h>
+#include <asm/uaccess.h>
+#include <asm/io.h>
+
+#include <linux/scx200.h>
+
+#define NAME "scx200_wdt"
+
+MODULE_AUTHOR("Christer Weinigel <wingel@nano-system.com>");
+MODULE_DESCRIPTION("NatSemi SCx200 Watchdog Driver");
+MODULE_LICENSE("GPL");
+
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+#define CONFIG_WATCHDOG_NOWAYOUT 0
+#endif
+
+static int margin = 60;		/* in seconds */
+MODULE_PARM(margin, "i");
+MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
+
+static int nowayout = CONFIG_WATCHDOG_NOWAYOUT;
+MODULE_PARM(nowayout, "i");
+MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
+
+static u16 wdto_restart;
+static struct semaphore open_semaphore;
+static unsigned expect_close;
+
+/* Bits of the WDCNFG register */
+#define W_ENABLE 0x00fa		/* Enable watchdog */
+#define W_DISABLE 0x0000	/* Disable watchdog */
+
+/* The scaling factor for the timer, this depends on the value of W_ENABLE */
+#define W_SCALE (32768/1024)
+
+static void scx200_wdt_ping(void)
+{
+	outw(wdto_restart, SCx200_CB_BASE + SCx200_WDT_WDTO);
+}
+
+static void scx200_wdt_update_margin(void)
+{
+	printk(KERN_INFO NAME ": timer margin %d seconds\n", margin);
+	wdto_restart = margin * W_SCALE;
+}
+
+static void scx200_wdt_enable(void)
+{
+	printk(KERN_DEBUG NAME ": enabling watchdog timer, wdto_restart = %d\n", 
+	       wdto_restart);
+
+	outw(0, SCx200_CB_BASE + SCx200_WDT_WDTO);
+	outb(SCx200_WDT_WDSTS_WDOVF, SCx200_CB_BASE + SCx200_WDT_WDSTS);
+	outw(W_ENABLE, SCx200_CB_BASE + SCx200_WDT_WDCNFG);
+
+	scx200_wdt_ping();
+}
+
+static void scx200_wdt_disable(void)
+{
+	printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
+		
+	outw(0, SCx200_CB_BASE + SCx200_WDT_WDTO);
+	outb(SCx200_WDT_WDSTS_WDOVF, SCx200_CB_BASE + SCx200_WDT_WDSTS);
+	outw(W_DISABLE, SCx200_CB_BASE + SCx200_WDT_WDCNFG);
+}
+
+static int scx200_wdt_open(struct inode *inode, struct file *file)
+{
+        /* only allow one at a time */
+        if (down_trylock(&open_semaphore))
+                return -EBUSY;
+	scx200_wdt_enable();
+	expect_close = 0;
+
+	return 0;
+}
+
+static int scx200_wdt_release(struct inode *inode, struct file *file)
+{
+	if (!expect_close) {
+		printk(KERN_WARNING NAME ": watchdog device closed unexpectedly, will not disable the watchdog timer\n");
+	} else if (!nowayout) {
+		scx200_wdt_disable();
+	}
+        up(&open_semaphore);
+
+	return 0;
+}
+
+static int scx200_wdt_notify_sys(struct notifier_block *this, 
+				      unsigned long code, void *unused)
+{
+        if (code == SYS_HALT || code == SYS_POWER_OFF)
+		if (!nowayout)
+			scx200_wdt_disable();
+
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block scx200_wdt_notifier =
+{
+        notifier_call: scx200_wdt_notify_sys
+};
+
+static ssize_t scx200_wdt_write(struct file *file, const char *data, 
+				     size_t len, loff_t *ppos)
+{
+	if (ppos != &file->f_pos)
+		return -ESPIPE;
+
+	/* check for a magic close character */
+	if (len) 
+	{
+		size_t i;
+
+		scx200_wdt_ping();
+
+		expect_close = 0;
+		for (i = 0; i < len; ++i) {
+			char c;
+			if (get_user(c, data+i))
+				return -EFAULT;
+			if (c == 'V')
+				expect_close = 1;
+		}
+
+		return len;
+	}
+
+	return 0;
+}
+
+static int scx200_wdt_ioctl(struct inode *inode, struct file *file,
+	unsigned int cmd, unsigned long arg)
+{
+	static struct watchdog_info ident = {
+		.identity = "NatSemi SCx200 Watchdog",
+		.firmware_version = 1, 
+		.options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING),
+	};
+	int new_margin;
+	
+	switch (cmd) {
+	default:
+		return -ENOTTY;
+	case WDIOC_GETSUPPORT:
+		if(copy_to_user((struct watchdog_info *)arg, &ident, 
+				sizeof(ident)))
+			return -EFAULT;
+		return 0;
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		if (put_user(0, (int *)arg))
+			return -EFAULT;
+		return 0;
+	case WDIOC_KEEPALIVE:
+		scx200_wdt_ping();
+		return 0;
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_margin, (int *)arg))
+			return -EFAULT;
+		if (new_margin < 1)
+			return -EINVAL;
+		margin = new_margin;
+		scx200_wdt_update_margin();
+		scx200_wdt_ping();
+	case WDIOC_GETTIMEOUT:
+		if (put_user(margin, (int *)arg))
+			return -EFAULT;
+		return 0;
+	}
+}
+
+static struct file_operations scx200_wdt_fops = {
+	.owner	 = THIS_MODULE,
+	.write   = scx200_wdt_write,
+	.ioctl   = scx200_wdt_ioctl,
+	.open    = scx200_wdt_open,
+	.release = scx200_wdt_release,
+};
+
+static struct miscdevice scx200_wdt_miscdev = {
+	.minor = WATCHDOG_MINOR,
+	.name  = NAME,
+	.fops  = &scx200_wdt_fops,
+};
+
+static int __init scx200_wdt_init(void)
+{
+	int r;
+
+	printk(KERN_DEBUG NAME ": NatSemi SCx200 Watchdog Driver\n");
+
+	/* First check that this really is a NatSemi SCx200 CPU */
+	if ((pci_find_device(PCI_VENDOR_ID_NS, 
+			     PCI_DEVICE_ID_NS_SCx200_BRIDGE,
+			     NULL)) == NULL)
+		return -ENODEV;
+
+	/* More sanity checks, verify that the configuration block is there */
+	if (!scx200_cb_probe(SCx200_CB_BASE)) {
+		printk(KERN_WARNING NAME ": no configuration block found\n");
+		return -ENODEV;
+	}
+
+	if (!request_region(SCx200_CB_BASE + SCx200_WDT_OFFSET, 
+			    SCx200_WDT_SIZE, 
+			    "NatSemi SCx200 Watchdog")) {
+		printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
+		return -EBUSY;
+	}
+
+	scx200_wdt_update_margin();
+	scx200_wdt_disable();
+
+	sema_init(&open_semaphore, 1);
+
+	r = misc_register(&scx200_wdt_miscdev);
+	if (r)
+		return r;
+
+	r = register_reboot_notifier(&scx200_wdt_notifier);
+        if (r) {
+                printk(KERN_ERR NAME ": unable to register reboot notifier");
+		misc_deregister(&scx200_wdt_miscdev);
+                return r;
+        }
+
+	return 0;
+}
+
+static void __exit scx200_wdt_cleanup(void)
+{
+        unregister_reboot_notifier(&scx200_wdt_notifier);
+	misc_deregister(&scx200_wdt_miscdev);
+	release_region(SCx200_CB_BASE + SCx200_WDT_OFFSET,
+		       SCx200_WDT_SIZE);
+}
+
+module_init(scx200_wdt_init);
+module_exit(scx200_wdt_cleanup);
+
+/*
+    Local variables:
+        compile-command: "make -k -C ../.. SUBDIRS=drivers/char modules"
+        c-basic-offset: 8
+    End:
+*/