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18#include <linux/fs.h>
19#include <linux/init.h>
20#include <linux/kernel.h>
21#include <linux/miscdevice.h>
22#include <linux/platform_device.h>
23#include <linux/module.h>
24#include <linux/watchdog.h>
25#include <asm/io.h>
26#include <asm/uaccess.h>
27
28struct mpc83xx_wdt {
29 __be32 res0;
30 __be32 swcrr;
31#define SWCRR_SWTC 0xFFFF0000
32#define SWCRR_SWEN 0x00000004
33#define SWCRR_SWRI 0x00000002
34#define SWCRR_SWPR 0x00000001
35 __be32 swcnr;
36 u8 res1[2];
37 __be16 swsrr;
38 u8 res2[0xF0];
39};
40
41static struct mpc83xx_wdt __iomem *wd_base;
42
43static u16 timeout = 0xffff;
44module_param(timeout, ushort, 0);
45MODULE_PARM_DESC(timeout, "Watchdog timeout in ticks. (0<timeout<65536, default=65535");
46
47static int reset = 1;
48module_param(reset, bool, 0);
49MODULE_PARM_DESC(reset, "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
50
51
52
53
54
55static int prescale = 1;
56static unsigned int timeout_sec;
57
58static unsigned long wdt_is_open;
59static DEFINE_SPINLOCK(wdt_spinlock);
60
61static void mpc83xx_wdt_keepalive(void)
62{
63
64 spin_lock(&wdt_spinlock);
65 out_be16(&wd_base->swsrr, 0x556c);
66 out_be16(&wd_base->swsrr, 0xaa39);
67 spin_unlock(&wdt_spinlock);
68}
69
70static ssize_t mpc83xx_wdt_write(struct file *file, const char __user *buf,
71 size_t count, loff_t *ppos)
72{
73 if (count)
74 mpc83xx_wdt_keepalive();
75 return count;
76}
77
78static int mpc83xx_wdt_open(struct inode *inode, struct file *file)
79{
80 u32 tmp = SWCRR_SWEN;
81 if (test_and_set_bit(0, &wdt_is_open))
82 return -EBUSY;
83
84
85 __module_get(THIS_MODULE);
86
87
88 if (prescale)
89 tmp |= SWCRR_SWPR;
90 if (reset)
91 tmp |= SWCRR_SWRI;
92
93 tmp |= timeout << 16;
94
95 out_be32(&wd_base->swcrr, tmp);
96
97 return nonseekable_open(inode, file);
98}
99
100static int mpc83xx_wdt_release(struct inode *inode, struct file *file)
101{
102 printk(KERN_CRIT "Unexpected close, not stopping watchdog!\n");
103 mpc83xx_wdt_keepalive();
104 clear_bit(0, &wdt_is_open);
105 return 0;
106}
107
108static int mpc83xx_wdt_ioctl(struct inode *inode, struct file *file,
109 unsigned int cmd, unsigned long arg)
110{
111 void __user *argp = (void __user *)arg;
112 int __user *p = argp;
113 static struct watchdog_info ident = {
114 .options = WDIOF_KEEPALIVEPING,
115 .firmware_version = 1,
116 .identity = "MPC83xx",
117 };
118
119 switch (cmd) {
120 case WDIOC_GETSUPPORT:
121 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
122 case WDIOC_GETSTATUS:
123 case WDIOC_GETBOOTSTATUS:
124 return put_user(0, p);
125 case WDIOC_KEEPALIVE:
126 mpc83xx_wdt_keepalive();
127 return 0;
128 case WDIOC_GETTIMEOUT:
129 return put_user(timeout_sec, p);
130 default:
131 return -ENOTTY;
132 }
133}
134
135static const struct file_operations mpc83xx_wdt_fops = {
136 .owner = THIS_MODULE,
137 .llseek = no_llseek,
138 .write = mpc83xx_wdt_write,
139 .ioctl = mpc83xx_wdt_ioctl,
140 .open = mpc83xx_wdt_open,
141 .release = mpc83xx_wdt_release,
142};
143
144static struct miscdevice mpc83xx_wdt_miscdev = {
145 .minor = WATCHDOG_MINOR,
146 .name = "watchdog",
147 .fops = &mpc83xx_wdt_fops,
148};
149
150static int __devinit mpc83xx_wdt_probe(struct platform_device *dev)
151{
152 struct resource *r;
153 int ret;
154 unsigned int *freq = dev->dev.platform_data;
155
156
157 r = platform_get_resource(dev, IORESOURCE_MEM, 0);
158
159 if (!r) {
160 ret = -ENODEV;
161 goto err_out;
162 }
163
164 wd_base = ioremap(r->start, sizeof (struct mpc83xx_wdt));
165
166 if (wd_base == NULL) {
167 ret = -ENOMEM;
168 goto err_out;
169 }
170
171 ret = misc_register(&mpc83xx_wdt_miscdev);
172 if (ret) {
173 printk(KERN_ERR "cannot register miscdev on minor=%d "
174 "(err=%d)\n",
175 WATCHDOG_MINOR, ret);
176 goto err_unmap;
177 }
178
179
180 if (prescale)
181 timeout_sec = (timeout * 0x10000) / (*freq);
182 else
183 timeout_sec = timeout / (*freq);
184
185 printk(KERN_INFO "WDT driver for MPC83xx initialized. "
186 "mode:%s timeout=%d (%d seconds)\n",
187 reset ? "reset":"interrupt", timeout, timeout_sec);
188 return 0;
189
190err_unmap:
191 iounmap(wd_base);
192err_out:
193 return ret;
194}
195
196static int __devexit mpc83xx_wdt_remove(struct platform_device *dev)
197{
198 misc_deregister(&mpc83xx_wdt_miscdev);
199 iounmap(wd_base);
200
201 return 0;
202}
203
204static struct platform_driver mpc83xx_wdt_driver = {
205 .probe = mpc83xx_wdt_probe,
206 .remove = __devexit_p(mpc83xx_wdt_remove),
207 .driver = {
208 .name = "mpc83xx_wdt",
209 },
210};
211
212static int __init mpc83xx_wdt_init(void)
213{
214 return platform_driver_register(&mpc83xx_wdt_driver);
215}
216
217static void __exit mpc83xx_wdt_exit(void)
218{
219 platform_driver_unregister(&mpc83xx_wdt_driver);
220}
221
222module_init(mpc83xx_wdt_init);
223module_exit(mpc83xx_wdt_exit);
224
225MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
226MODULE_DESCRIPTION("Driver for watchdog timer in MPC83xx uProcessor");
227MODULE_LICENSE("GPL");
228MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
229
