2 * drivers/watchdog/m54xx_wdt.c
4 * Watchdog driver for ColdFire MCF547x & MCF548x processors
5 * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be>
7 * Adapted from the IXP4xx watchdog driver, which carries these notices:
9 * Author: Deepak Saxena <dsaxena@plexity.net>
11 * Copyright 2004 (c) MontaVista, Software, Inc.
12 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
19 #include <linux/module.h>
20 #include <linux/moduleparam.h>
21 #include <linux/types.h>
22 #include <linux/kernel.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>
31 #include <asm/coldfire.h>
32 #include <asm/m54xxsim.h>
33 #include <asm/m54xxgpt.h>
35 static int nowayout = WATCHDOG_NOWAYOUT;
36 static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */
37 static unsigned long wdt_status;
40 #define WDT_OK_TO_CLOSE 1
42 static void wdt_enable(void)
46 /* preserve GPIO usage, if any */
47 gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
48 if (gms0 & MCF_GPT_GMS_TMS_GPIO)
49 gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK
52 gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD;
53 __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
54 __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) |
55 MCF_GPT_GCIR_CNT(0xffff), MCF_MBAR + MCF_GPT_GCIR0);
56 gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE;
57 __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
60 static void wdt_disable(void)
64 /* disable watchdog */
65 gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
66 gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE);
67 __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
70 static void wdt_keepalive(void)
74 gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
75 gms0 |= MCF_GPT_GMS_OCPW(0xA5);
76 __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
79 static int m54xx_wdt_open(struct inode *inode, struct file *file)
81 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
84 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
86 return nonseekable_open(inode, file);
89 static ssize_t m54xx_wdt_write(struct file *file, const char *data,
90 size_t len, loff_t *ppos)
96 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
98 for (i = 0; i != len; i++) {
101 if (get_user(c, data + i))
104 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
112 static const struct watchdog_info ident = {
113 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
115 .identity = "Coldfire M54xx Watchdog",
118 static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
125 case WDIOC_GETSUPPORT:
126 ret = copy_to_user((struct watchdog_info *)arg, &ident,
127 sizeof(ident)) ? -EFAULT : 0;
130 case WDIOC_GETSTATUS:
131 ret = put_user(0, (int *)arg);
134 case WDIOC_GETBOOTSTATUS:
135 ret = put_user(0, (int *)arg);
138 case WDIOC_KEEPALIVE:
143 case WDIOC_SETTIMEOUT:
144 ret = get_user(time, (int *)arg);
148 if (time <= 0 || time > 30) {
157 case WDIOC_GETTIMEOUT:
158 ret = put_user(heartbeat, (int *)arg);
164 static int m54xx_wdt_release(struct inode *inode, struct file *file)
166 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
169 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
170 "timer will not stop\n");
173 clear_bit(WDT_IN_USE, &wdt_status);
174 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
180 static const struct file_operations m54xx_wdt_fops = {
181 .owner = THIS_MODULE,
183 .write = m54xx_wdt_write,
184 .unlocked_ioctl = m54xx_wdt_ioctl,
185 .open = m54xx_wdt_open,
186 .release = m54xx_wdt_release,
189 static struct miscdevice m54xx_wdt_miscdev = {
190 .minor = WATCHDOG_MINOR,
192 .fops = &m54xx_wdt_fops,
195 static int __init m54xx_wdt_init(void)
197 if (!request_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4,
198 "Coldfire M54xx Watchdog")) {
200 "Coldfire M54xx Watchdog : I/O region busy\n");
203 printk(KERN_INFO "ColdFire watchdog driver is loaded.\n");
205 return misc_register(&m54xx_wdt_miscdev);
208 static void __exit m54xx_wdt_exit(void)
210 misc_deregister(&m54xx_wdt_miscdev);
211 release_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4);
214 module_init(m54xx_wdt_init);
215 module_exit(m54xx_wdt_exit);
217 MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
218 MODULE_DESCRIPTION("Coldfire M54xx Watchdog");
220 module_param(heartbeat, int, 0);
221 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");
223 module_param(nowayout, int, 0);
224 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
226 MODULE_LICENSE("GPL");
227 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);