m68knommu: Rename m548x_wdt.c to m54xx_wdt.c
[linux-2.6.git] / drivers / watchdog / m54xx_wdt.c
1 /*
2  * drivers/watchdog/m54xx_wdt.c
3  *
4  * Watchdog driver for ColdFire MCF547x & MCF548x processors
5  * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be>
6  *
7  * Adapted from the IXP4xx watchdog driver, which carries these notices:
8  *
9  *  Author: Deepak Saxena <dsaxena@plexity.net>
10  *
11  *  Copyright 2004 (c) MontaVista, Software, Inc.
12  *  Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
13  *
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.
17  */
18
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
31 #include <asm/coldfire.h>
32 #include <asm/m54xxsim.h>
33 #include <asm/m54xxgpt.h>
34
35 static int nowayout = WATCHDOG_NOWAYOUT;
36 static unsigned int heartbeat = 30;     /* (secs) Default is 0.5 minute */
37 static unsigned long wdt_status;
38
39 #define WDT_IN_USE              0
40 #define WDT_OK_TO_CLOSE         1
41
42 static void wdt_enable(void)
43 {
44         unsigned int gms0;
45
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
50                                                         | MCF_GPT_GMS_OD);
51         else
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);
58 }
59
60 static void wdt_disable(void)
61 {
62         unsigned int gms0;
63
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);
68 }
69
70 static void wdt_keepalive(void)
71 {
72         unsigned int gms0;
73
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);
77 }
78
79 static int m54xx_wdt_open(struct inode *inode, struct file *file)
80 {
81         if (test_and_set_bit(WDT_IN_USE, &wdt_status))
82                 return -EBUSY;
83
84         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
85         wdt_enable();
86         return nonseekable_open(inode, file);
87 }
88
89 static ssize_t m54xx_wdt_write(struct file *file, const char *data,
90                                                 size_t len, loff_t *ppos)
91 {
92         if (len) {
93                 if (!nowayout) {
94                         size_t i;
95
96                         clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
97
98                         for (i = 0; i != len; i++) {
99                                 char c;
100
101                                 if (get_user(c, data + i))
102                                         return -EFAULT;
103                                 if (c == 'V')
104                                         set_bit(WDT_OK_TO_CLOSE, &wdt_status);
105                         }
106                 }
107                 wdt_keepalive();
108         }
109         return len;
110 }
111
112 static const struct watchdog_info ident = {
113         .options        = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
114                                 WDIOF_KEEPALIVEPING,
115         .identity       = "Coldfire M54xx Watchdog",
116 };
117
118 static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
119                                                          unsigned long arg)
120 {
121         int ret = -ENOTTY;
122         int time;
123
124         switch (cmd) {
125         case WDIOC_GETSUPPORT:
126                 ret = copy_to_user((struct watchdog_info *)arg, &ident,
127                                    sizeof(ident)) ? -EFAULT : 0;
128                 break;
129
130         case WDIOC_GETSTATUS:
131                 ret = put_user(0, (int *)arg);
132                 break;
133
134         case WDIOC_GETBOOTSTATUS:
135                 ret = put_user(0, (int *)arg);
136                 break;
137
138         case WDIOC_KEEPALIVE:
139                 wdt_keepalive();
140                 ret = 0;
141                 break;
142
143         case WDIOC_SETTIMEOUT:
144                 ret = get_user(time, (int *)arg);
145                 if (ret)
146                         break;
147
148                 if (time <= 0 || time > 30) {
149                         ret = -EINVAL;
150                         break;
151                 }
152
153                 heartbeat = time;
154                 wdt_enable();
155                 /* Fall through */
156
157         case WDIOC_GETTIMEOUT:
158                 ret = put_user(heartbeat, (int *)arg);
159                 break;
160         }
161         return ret;
162 }
163
164 static int m54xx_wdt_release(struct inode *inode, struct file *file)
165 {
166         if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
167                 wdt_disable();
168         else {
169                 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
170                                         "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
180 static const struct file_operations m54xx_wdt_fops = {
181         .owner          = THIS_MODULE,
182         .llseek         = no_llseek,
183         .write          = m54xx_wdt_write,
184         .unlocked_ioctl = m54xx_wdt_ioctl,
185         .open           = m54xx_wdt_open,
186         .release        = m54xx_wdt_release,
187 };
188
189 static struct miscdevice m54xx_wdt_miscdev = {
190         .minor          = WATCHDOG_MINOR,
191         .name           = "watchdog",
192         .fops           = &m54xx_wdt_fops,
193 };
194
195 static int __init m54xx_wdt_init(void)
196 {
197         if (!request_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4,
198                                                 "Coldfire M54xx Watchdog")) {
199                 printk(KERN_WARNING
200                                 "Coldfire M54xx Watchdog : I/O region busy\n");
201                 return -EBUSY;
202         }
203         printk(KERN_INFO "ColdFire watchdog driver is loaded.\n");
204
205         return misc_register(&m54xx_wdt_miscdev);
206 }
207
208 static void __exit m54xx_wdt_exit(void)
209 {
210         misc_deregister(&m54xx_wdt_miscdev);
211         release_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4);
212 }
213
214 module_init(m54xx_wdt_init);
215 module_exit(m54xx_wdt_exit);
216
217 MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
218 MODULE_DESCRIPTION("Coldfire M54xx Watchdog");
219
220 module_param(heartbeat, int, 0);
221 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");
222
223 module_param(nowayout, int, 0);
224 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
225
226 MODULE_LICENSE("GPL");
227 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);