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1 | /* riowd.c - driver for hw watchdog inside Super I/O of RIO |
2 | * |
3 | * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net) |
4 | */ |
5 | |
6 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/module.h> |
10 | #include <linux/types.h> |
11 | #include <linux/fs.h> |
12 | #include <linux/errno.h> |
13 | #include <linux/init.h> |
14 | #include <linux/miscdevice.h> |
15 | #include <linux/watchdog.h> |
16 | #include <linux/of.h> |
17 | #include <linux/of_device.h> |
18 | #include <linux/io.h> |
19 | #include <linux/uaccess.h> |
20 | #include <linux/slab.h> |
21 | |
22 | |
23 | /* RIO uses the NatSemi Super I/O power management logical device |
24 | * as its' watchdog. |
25 | * |
26 | * When the watchdog triggers, it asserts a line to the BBC (Boot Bus |
27 | * Controller) of the machine. The BBC can only be configured to |
28 | * trigger a power-on reset when the signal is asserted. The BBC |
29 | * can be configured to ignore the signal entirely as well. |
30 | * |
31 | * The only Super I/O device register we care about is at index |
32 | * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255). |
33 | * If set to zero, this disables the watchdog. When set, the system |
34 | * must periodically (before watchdog expires) clear (set to zero) and |
35 | * re-set the watchdog else it will trigger. |
36 | * |
37 | * There are two other indexed watchdog registers inside this Super I/O |
38 | * logical device, but they are unused. The first, at index 0x06 is |
39 | * the watchdog control and can be used to make the watchdog timer re-set |
40 | * when the PS/2 mouse or serial lines show activity. The second, at |
41 | * index 0x07 is merely a sampling of the line from the watchdog to the |
42 | * BBC. |
43 | * |
44 | * The watchdog device generates no interrupts. |
45 | */ |
46 | |
47 | MODULE_AUTHOR("David S. Miller <davem@davemloft.net>"); |
48 | MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO"); |
49 | MODULE_SUPPORTED_DEVICE("watchdog"); |
50 | MODULE_LICENSE("GPL"); |
51 | |
52 | #define DRIVER_NAME "riowd" |
53 | #define PFX DRIVER_NAME ": " |
54 | |
55 | struct riowd { |
56 | void __iomem *regs; |
57 | spinlock_t lock; |
58 | }; |
59 | |
60 | static struct riowd *riowd_device; |
61 | |
62 | #define WDTO_INDEX 0x05 |
63 | |
64 | static int riowd_timeout = 1; /* in minutes */ |
65 | module_param(riowd_timeout, int, 0); |
66 | MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes"); |
67 | |
68 | static void riowd_writereg(struct riowd *p, u8 val, int index) |
69 | { |
70 | unsigned long flags; |
71 | |
72 | spin_lock_irqsave(&p->lock, flags); |
73 | writeb(index, p->regs + 0); |
74 | writeb(val, p->regs + 1); |
75 | spin_unlock_irqrestore(&p->lock, flags); |
76 | } |
77 | |
78 | static int riowd_open(struct inode *inode, struct file *filp) |
79 | { |
80 | nonseekable_open(inode, filp); |
81 | return 0; |
82 | } |
83 | |
84 | static int riowd_release(struct inode *inode, struct file *filp) |
85 | { |
86 | return 0; |
87 | } |
88 | |
89 | static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) |
90 | { |
91 | static const struct watchdog_info info = { |
92 | .options = WDIOF_SETTIMEOUT, |
93 | .firmware_version = 1, |
94 | .identity = DRIVER_NAME, |
95 | }; |
96 | void __user *argp = (void __user *)arg; |
97 | struct riowd *p = riowd_device; |
98 | unsigned int options; |
99 | int new_margin; |
100 | |
101 | switch (cmd) { |
102 | case WDIOC_GETSUPPORT: |
103 | if (copy_to_user(argp, &info, sizeof(info))) |
104 | return -EFAULT; |
105 | break; |
106 | |
107 | case WDIOC_GETSTATUS: |
108 | case WDIOC_GETBOOTSTATUS: |
109 | if (put_user(0, (int __user *)argp)) |
110 | return -EFAULT; |
111 | break; |
112 | |
113 | case WDIOC_KEEPALIVE: |
114 | riowd_writereg(p, riowd_timeout, WDTO_INDEX); |
115 | break; |
116 | |
117 | case WDIOC_SETOPTIONS: |
118 | if (copy_from_user(&options, argp, sizeof(options))) |
119 | return -EFAULT; |
120 | |
121 | if (options & WDIOS_DISABLECARD) |
122 | riowd_writereg(p, 0, WDTO_INDEX); |
123 | else if (options & WDIOS_ENABLECARD) |
124 | riowd_writereg(p, riowd_timeout, WDTO_INDEX); |
125 | else |
126 | return -EINVAL; |
127 | |
128 | break; |
129 | |
130 | case WDIOC_SETTIMEOUT: |
131 | if (get_user(new_margin, (int __user *)argp)) |
132 | return -EFAULT; |
133 | if ((new_margin < 60) || (new_margin > (255 * 60))) |
134 | return -EINVAL; |
135 | riowd_timeout = (new_margin + 59) / 60; |
136 | riowd_writereg(p, riowd_timeout, WDTO_INDEX); |
137 | /* Fall */ |
138 | |
139 | case WDIOC_GETTIMEOUT: |
140 | return put_user(riowd_timeout * 60, (int __user *)argp); |
141 | |
142 | default: |
143 | return -EINVAL; |
144 | }; |
145 | |
146 | return 0; |
147 | } |
148 | |
149 | static ssize_t riowd_write(struct file *file, const char __user *buf, |
150 | size_t count, loff_t *ppos) |
151 | { |
152 | struct riowd *p = riowd_device; |
153 | |
154 | if (count) { |
155 | riowd_writereg(p, riowd_timeout, WDTO_INDEX); |
156 | return 1; |
157 | } |
158 | |
159 | return 0; |
160 | } |
161 | |
162 | static const struct file_operations riowd_fops = { |
163 | .owner = THIS_MODULE, |
164 | .llseek = no_llseek, |
165 | .unlocked_ioctl = riowd_ioctl, |
166 | .open = riowd_open, |
167 | .write = riowd_write, |
168 | .release = riowd_release, |
169 | }; |
170 | |
171 | static struct miscdevice riowd_miscdev = { |
172 | .minor = WATCHDOG_MINOR, |
173 | .name = "watchdog", |
174 | .fops = &riowd_fops |
175 | }; |
176 | |
177 | static int riowd_probe(struct platform_device *op) |
178 | { |
179 | struct riowd *p; |
180 | int err = -EINVAL; |
181 | |
182 | if (riowd_device) |
183 | goto out; |
184 | |
185 | err = -ENOMEM; |
186 | p = kzalloc(sizeof(*p), GFP_KERNEL); |
187 | if (!p) |
188 | goto out; |
189 | |
190 | spin_lock_init(&p->lock); |
191 | |
192 | p->regs = of_ioremap(&op->resource[0], 0, 2, DRIVER_NAME); |
193 | if (!p->regs) { |
194 | pr_err("Cannot map registers\n"); |
195 | goto out_free; |
196 | } |
197 | /* Make miscdev useable right away */ |
198 | riowd_device = p; |
199 | |
200 | err = misc_register(&riowd_miscdev); |
201 | if (err) { |
202 | pr_err("Cannot register watchdog misc device\n"); |
203 | goto out_iounmap; |
204 | } |
205 | |
206 | pr_info("Hardware watchdog [%i minutes], regs at %p\n", |
207 | riowd_timeout, p->regs); |
208 | |
209 | dev_set_drvdata(&op->dev, p); |
210 | return 0; |
211 | |
212 | out_iounmap: |
213 | riowd_device = NULL; |
214 | of_iounmap(&op->resource[0], p->regs, 2); |
215 | |
216 | out_free: |
217 | kfree(p); |
218 | |
219 | out: |
220 | return err; |
221 | } |
222 | |
223 | static int riowd_remove(struct platform_device *op) |
224 | { |
225 | struct riowd *p = dev_get_drvdata(&op->dev); |
226 | |
227 | misc_deregister(&riowd_miscdev); |
228 | of_iounmap(&op->resource[0], p->regs, 2); |
229 | kfree(p); |
230 | |
231 | return 0; |
232 | } |
233 | |
234 | static const struct of_device_id riowd_match[] = { |
235 | { |
236 | .name = "pmc", |
237 | }, |
238 | {}, |
239 | }; |
240 | MODULE_DEVICE_TABLE(of, riowd_match); |
241 | |
242 | static struct platform_driver riowd_driver = { |
243 | .driver = { |
244 | .name = DRIVER_NAME, |
245 | .owner = THIS_MODULE, |
246 | .of_match_table = riowd_match, |
247 | }, |
248 | .probe = riowd_probe, |
249 | .remove = riowd_remove, |
250 | }; |
251 | |
252 | module_platform_driver(riowd_driver); |
253 |
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