Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  *	SBC EPX C3 0.1	A Hardware Watchdog Device for the Winsystems EPX-C3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  *	single board computer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *	(c) Copyright 2006 Calin A. Culianu <calin@ajvar.org>, All Rights
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  *	Reserved.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  *	based on softdog.c by Alan Cox <alan@lxorguk.ukuu.org.uk>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) #include <linux/moduleparam.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/kernel.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/fs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <linux/miscdevice.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) #include <linux/watchdog.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #include <linux/notifier.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #include <linux/reboot.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #include <linux/ioport.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #include <linux/io.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) static int epx_c3_alive;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) #define WATCHDOG_TIMEOUT 1		/* 1 sec default timeout */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) static bool nowayout = WATCHDOG_NOWAYOUT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) module_param(nowayout, bool, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) 					__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) #define EPXC3_WATCHDOG_CTL_REG 0x1ee /* write 1 to enable, 0 to disable */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) #define EPXC3_WATCHDOG_PET_REG 0x1ef /* write anything to pet once enabled */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) static void epx_c3_start(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	outb(1, EPXC3_WATCHDOG_CTL_REG);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) static void epx_c3_stop(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	outb(0, EPXC3_WATCHDOG_CTL_REG);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	pr_info("Stopped watchdog timer\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) static void epx_c3_pet(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 	outb(1, EPXC3_WATCHDOG_PET_REG);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60)  *	Allow only one person to hold it open
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) static int epx_c3_open(struct inode *inode, struct file *file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	if (epx_c3_alive)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 		return -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 	if (nowayout)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 		__module_get(THIS_MODULE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 	/* Activate timer */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	epx_c3_start();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	epx_c3_pet();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	epx_c3_alive = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	pr_info("Started watchdog timer\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	return stream_open(inode, file);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) static int epx_c3_release(struct inode *inode, struct file *file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	/* Shut off the timer.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) 	 * Lock it in if it's a module and we defined ...NOWAYOUT */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 	if (!nowayout)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 		epx_c3_stop();		/* Turn the WDT off */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	epx_c3_alive = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) static ssize_t epx_c3_write(struct file *file, const char __user *data,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 			size_t len, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 	/* Refresh the timer. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 	if (len)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 		epx_c3_pet();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	return len;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) static long epx_c3_ioctl(struct file *file, unsigned int cmd,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 						unsigned long arg)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	int options, retval = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	int __user *argp = (void __user *)arg;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	static const struct watchdog_info ident = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 		.options		= WDIOF_KEEPALIVEPING,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 		.firmware_version	= 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 		.identity		= "Winsystems EPX-C3 H/W Watchdog",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	};
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 	switch (cmd) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	case WDIOC_GETSUPPORT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 		if (copy_to_user(argp, &ident, sizeof(ident)))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	case WDIOC_GETSTATUS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	case WDIOC_GETBOOTSTATUS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 		return put_user(0, argp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 	case WDIOC_SETOPTIONS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 		if (get_user(options, argp))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 		if (options & WDIOS_DISABLECARD) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 			epx_c3_stop();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 			retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 		if (options & WDIOS_ENABLECARD) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 			epx_c3_start();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) 			retval = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 		return retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) 	case WDIOC_KEEPALIVE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 		epx_c3_pet();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) 	case WDIOC_GETTIMEOUT:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 		return put_user(WATCHDOG_TIMEOUT, argp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 		return -ENOTTY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) static int epx_c3_notify_sys(struct notifier_block *this, unsigned long code,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 				void *unused)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	if (code == SYS_DOWN || code == SYS_HALT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 		epx_c3_stop();		/* Turn the WDT off */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 	return NOTIFY_DONE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) static const struct file_operations epx_c3_fops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 	.owner		= THIS_MODULE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 	.llseek		= no_llseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	.write		= epx_c3_write,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	.unlocked_ioctl	= epx_c3_ioctl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	.compat_ioctl	= compat_ptr_ioctl,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	.open		= epx_c3_open,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	.release	= epx_c3_release,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) static struct miscdevice epx_c3_miscdev = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	.minor		= WATCHDOG_MINOR,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	.name		= "watchdog",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	.fops		= &epx_c3_fops,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) static struct notifier_block epx_c3_notifier = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	.notifier_call = epx_c3_notify_sys,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) static int __init watchdog_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	if (!request_region(EPXC3_WATCHDOG_CTL_REG, 2, "epxc3_watchdog"))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		return -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 	ret = register_reboot_notifier(&epx_c3_notifier);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	if (ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 		pr_err("cannot register reboot notifier (err=%d)\n", ret);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) 	ret = misc_register(&epx_c3_miscdev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	if (ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) 		       WATCHDOG_MINOR, ret);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 		unregister_reboot_notifier(&epx_c3_notifier);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 	pr_info("Hardware Watchdog Timer for Winsystems EPX-C3 SBC: 0.1\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) static void __exit watchdog_exit(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	misc_deregister(&epx_c3_miscdev);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	unregister_reboot_notifier(&epx_c3_notifier);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	release_region(EPXC3_WATCHDOG_CTL_REG, 2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) module_init(watchdog_init);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) module_exit(watchdog_exit);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) MODULE_AUTHOR("Calin A. Culianu <calin@ajvar.org>");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) MODULE_DESCRIPTION("Hardware Watchdog Device for Winsystems EPX-C3 SBC.  "
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 	"Note that there is no way to probe for this device -- "
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	"so only use it if you are *sure* you are running on this specific "
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 	"SBC system from Winsystems!  It writes to IO ports 0x1ee and 0x1ef!");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) MODULE_LICENSE("GPL");