225 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * drivers/watchdog/m54xx_wdt.c4 *5 * Watchdog driver for ColdFire MCF547x & MCF548x processors6 * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be>7 *8 * Adapted from the IXP4xx watchdog driver, which carries these notices:9 *10 * Author: Deepak Saxena <dsaxena@plexity.net>11 *12 * Copyright 2004 (c) MontaVista, Software, Inc.13 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>14 *15 */16 17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt18 19#include <linux/module.h>20#include <linux/moduleparam.h>21#include <linux/types.h>22#include <linux/kernel.h>23#include <linux/fs.h>24#include <linux/miscdevice.h>25#include <linux/watchdog.h>26#include <linux/init.h>27#include <linux/bitops.h>28#include <linux/ioport.h>29#include <linux/uaccess.h>30#include <linux/io.h>31 32#include <asm/coldfire.h>33#include <asm/m54xxsim.h>34#include <asm/m54xxgpt.h>35 36static bool nowayout = WATCHDOG_NOWAYOUT;37static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */38static unsigned long wdt_status;39 40#define WDT_IN_USE 041#define WDT_OK_TO_CLOSE 142 43static void wdt_enable(void)44{45 unsigned int gms0;46 47 /* preserve GPIO usage, if any */48 gms0 = __raw_readl(MCF_GPT_GMS0);49 if (gms0 & MCF_GPT_GMS_TMS_GPIO)50 gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK51 | MCF_GPT_GMS_OD);52 else53 gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD;54 __raw_writel(gms0, MCF_GPT_GMS0);55 __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) |56 MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0);57 gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE;58 __raw_writel(gms0, MCF_GPT_GMS0);59}60 61static void wdt_disable(void)62{63 unsigned int gms0;64 65 /* disable watchdog */66 gms0 = __raw_readl(MCF_GPT_GMS0);67 gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE);68 __raw_writel(gms0, MCF_GPT_GMS0);69}70 71static void wdt_keepalive(void)72{73 unsigned int gms0;74 75 gms0 = __raw_readl(MCF_GPT_GMS0);76 gms0 |= MCF_GPT_GMS_OCPW(0xA5);77 __raw_writel(gms0, MCF_GPT_GMS0);78}79 80static int m54xx_wdt_open(struct inode *inode, struct file *file)81{82 if (test_and_set_bit(WDT_IN_USE, &wdt_status))83 return -EBUSY;84 85 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);86 wdt_enable();87 return stream_open(inode, file);88}89 90static ssize_t m54xx_wdt_write(struct file *file, const char *data,91 size_t len, loff_t *ppos)92{93 if (len) {94 if (!nowayout) {95 size_t i;96 97 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);98 99 for (i = 0; i != len; i++) {100 char c;101 102 if (get_user(c, data + i))103 return -EFAULT;104 if (c == 'V')105 set_bit(WDT_OK_TO_CLOSE, &wdt_status);106 }107 }108 wdt_keepalive();109 }110 return len;111}112 113static const struct watchdog_info ident = {114 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |115 WDIOF_KEEPALIVEPING,116 .identity = "Coldfire M54xx Watchdog",117};118 119static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,120 unsigned long arg)121{122 int ret = -ENOTTY;123 int time;124 125 switch (cmd) {126 case WDIOC_GETSUPPORT:127 ret = copy_to_user((struct watchdog_info *)arg, &ident,128 sizeof(ident)) ? -EFAULT : 0;129 break;130 131 case WDIOC_GETSTATUS:132 ret = put_user(0, (int *)arg);133 break;134 135 case WDIOC_GETBOOTSTATUS:136 ret = put_user(0, (int *)arg);137 break;138 139 case WDIOC_KEEPALIVE:140 wdt_keepalive();141 ret = 0;142 break;143 144 case WDIOC_SETTIMEOUT:145 ret = get_user(time, (int *)arg);146 if (ret)147 break;148 149 if (time <= 0 || time > 30) {150 ret = -EINVAL;151 break;152 }153 154 heartbeat = time;155 wdt_enable();156 fallthrough;157 158 case WDIOC_GETTIMEOUT:159 ret = put_user(heartbeat, (int *)arg);160 break;161 }162 return ret;163}164 165static int m54xx_wdt_release(struct inode *inode, struct file *file)166{167 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))168 wdt_disable();169 else {170 pr_crit("Device closed unexpectedly - timer will not stop\n");171 wdt_keepalive();172 }173 clear_bit(WDT_IN_USE, &wdt_status);174 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);175 176 return 0;177}178 179 180static const struct file_operations m54xx_wdt_fops = {181 .owner = THIS_MODULE,182 .write = m54xx_wdt_write,183 .unlocked_ioctl = m54xx_wdt_ioctl,184 .compat_ioctl = compat_ptr_ioctl,185 .open = m54xx_wdt_open,186 .release = m54xx_wdt_release,187};188 189static struct miscdevice m54xx_wdt_miscdev = {190 .minor = WATCHDOG_MINOR,191 .name = "watchdog",192 .fops = &m54xx_wdt_fops,193};194 195static int __init m54xx_wdt_init(void)196{197 if (!request_mem_region(MCF_GPT_GCIR0, 4, "Coldfire M54xx Watchdog")) {198 pr_warn("I/O region busy\n");199 return -EBUSY;200 }201 pr_info("driver is loaded\n");202 203 return misc_register(&m54xx_wdt_miscdev);204}205 206static void __exit m54xx_wdt_exit(void)207{208 misc_deregister(&m54xx_wdt_miscdev);209 release_mem_region(MCF_GPT_GCIR0, 4);210}211 212module_init(m54xx_wdt_init);213module_exit(m54xx_wdt_exit);214 215MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");216MODULE_DESCRIPTION("Coldfire M54xx Watchdog");217 218module_param(heartbeat, int, 0);219MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");220 221module_param(nowayout, bool, 0);222MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");223 224MODULE_LICENSE("GPL");225