Fixed MTP to work with TWRP

arch/um/drivers/harddog_kern.c

@@ -0,0 +1,201 @@
+/* UML hardware watchdog, shamelessly stolen from:
+ *
+ *	SoftDog	0.05:	A Software Watchdog Device
+ *
+ *	(c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
+ *				http://www.redhat.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.
+ *
+ *	Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
+ *	warranty for any of this software. This material is provided
+ *	"AS-IS" and at no charge.
+ *
+ *	(c) Copyright 1995    Alan Cox <alan@lxorguk.ukuu.org.uk>
+ *
+ *	Software only watchdog driver. Unlike its big brother the WDT501P
+ *	driver this won't always recover a failed machine.
+ *
+ *  03/96: Angelo Haritsis <ah@doc.ic.ac.uk> :
+ *	Modularised.
+ *	Added soft_margin; use upon insmod to change the timer delay.
+ *	NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate
+ *	    minors.
+ *
+ *  19980911 Alan Cox
+ *	Made SMP safe for 2.3.x
+ *
+ *  20011127 Joel Becker (jlbec@evilplan.org>
+ *	Added soft_noboot; Allows testing the softdog trigger without
+ *	requiring a recompile.
+ *	Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT.
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/reboot.h>
+#include <linux/mutex.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <asm/uaccess.h>
+#include "mconsole.h"
+
+MODULE_LICENSE("GPL");
+
+static DEFINE_MUTEX(harddog_mutex);
+static DEFINE_SPINLOCK(lock);
+static int timer_alive;
+static int harddog_in_fd = -1;
+static int harddog_out_fd = -1;
+
+/*
+ *	Allow only one person to hold it open
+ */
+
+extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock);
+
+static int harddog_open(struct inode *inode, struct file *file)
+{
+	int err = -EBUSY;
+	char *sock = NULL;
+
+	mutex_lock(&harddog_mutex);
+	spin_lock(&lock);
+	if(timer_alive)
+		goto err;
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+	__module_get(THIS_MODULE);
+#endif
+
+#ifdef CONFIG_MCONSOLE
+	sock = mconsole_notify_socket();
+#endif
+	err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock);
+	if(err)
+		goto err;
+
+	timer_alive = 1;
+	spin_unlock(&lock);
+	mutex_unlock(&harddog_mutex);
+	return nonseekable_open(inode, file);
+err:
+	spin_unlock(&lock);
+	mutex_unlock(&harddog_mutex);
+	return err;
+}
+
+extern void stop_watchdog(int in_fd, int out_fd);
+
+static int harddog_release(struct inode *inode, struct file *file)
+{
+	/*
+	 *	Shut off the timer.
+	 */
+
+	spin_lock(&lock);
+
+	stop_watchdog(harddog_in_fd, harddog_out_fd);
+	harddog_in_fd = -1;
+	harddog_out_fd = -1;
+
+	timer_alive=0;
+	spin_unlock(&lock);
+
+	return 0;
+}
+
+extern int ping_watchdog(int fd);
+
+static ssize_t harddog_write(struct file *file, const char __user *data, size_t len,
+			     loff_t *ppos)
+{
+	/*
+	 *	Refresh the timer.
+	 */
+	if(len)
+		return ping_watchdog(harddog_out_fd);
+	return 0;
+}
+
+static int harddog_ioctl_unlocked(struct file *file,
+				  unsigned int cmd, unsigned long arg)
+{
+	void __user *argp= (void __user *)arg;
+	static struct watchdog_info ident = {
+		WDIOC_SETTIMEOUT,
+		0,
+		"UML Hardware Watchdog"
+	};
+	switch (cmd) {
+		default:
+			return -ENOTTY;
+		case WDIOC_GETSUPPORT:
+			if(copy_to_user(argp, &ident, sizeof(ident)))
+				return -EFAULT;
+			return 0;
+		case WDIOC_GETSTATUS:
+		case WDIOC_GETBOOTSTATUS:
+			return put_user(0,(int __user *)argp);
+		case WDIOC_KEEPALIVE:
+			return ping_watchdog(harddog_out_fd);
+	}
+}
+
+static long harddog_ioctl(struct file *file,
+			  unsigned int cmd, unsigned long arg)
+{
+	long ret;
+
+	mutex_lock(&harddog_mutex);
+	ret = harddog_ioctl_unlocked(file, cmd, arg);
+	mutex_unlock(&harddog_mutex);
+
+	return ret;
+}
+
+static const struct file_operations harddog_fops = {
+	.owner		= THIS_MODULE,
+	.write		= harddog_write,
+	.unlocked_ioctl	= harddog_ioctl,
+	.open		= harddog_open,
+	.release	= harddog_release,
+	.llseek		= no_llseek,
+};
+
+static struct miscdevice harddog_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &harddog_fops,
+};
+
+static char banner[] __initdata = KERN_INFO "UML Watchdog Timer\n";
+
+static int __init harddog_init(void)
+{
+	int ret;
+
+	ret = misc_register(&harddog_miscdev);
+
+	if (ret)
+		return ret;
+
+	printk(banner);
+
+	return 0;
+}
+
+static void __exit harddog_exit(void)
+{
+	misc_deregister(&harddog_miscdev);
+}
+
+module_init(harddog_init);
+module_exit(harddog_exit);