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1// SPDX-License-Identifier: GPL-2.0-only
2/* riowd.c - driver for hw watchdog inside Super I/O of RIO
3 *
4 * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
5 */
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/types.h>
12#include <linux/fs.h>
13#include <linux/errno.h>
14#include <linux/miscdevice.h>
15#include <linux/watchdog.h>
16#include <linux/of.h>
17#include <linux/platform_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
47MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
48MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO");
49MODULE_LICENSE("GPL");
50
51#define DRIVER_NAME "riowd"
52#define PFX DRIVER_NAME ": "
53
54struct riowd {
55 void __iomem *regs;
56 spinlock_t lock;
57};
58
59static struct riowd *riowd_device;
60
61#define WDTO_INDEX 0x05
62
63static int riowd_timeout = 1; /* in minutes */
64module_param(riowd_timeout, int, 0);
65MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes");
66
67static void riowd_writereg(struct riowd *p, u8 val, int index)
68{
69 unsigned long flags;
70
71 spin_lock_irqsave(&p->lock, flags);
72 writeb(index, p->regs + 0);
73 writeb(val, p->regs + 1);
74 spin_unlock_irqrestore(&p->lock, flags);
75}
76
77static int riowd_open(struct inode *inode, struct file *filp)
78{
79 stream_open(inode, filp);
80 return 0;
81}
82
83static int riowd_release(struct inode *inode, struct file *filp)
84{
85 return 0;
86}
87
88static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
89{
90 static const struct watchdog_info info = {
91 .options = WDIOF_SETTIMEOUT,
92 .firmware_version = 1,
93 .identity = DRIVER_NAME,
94 };
95 void __user *argp = (void __user *)arg;
96 struct riowd *p = riowd_device;
97 unsigned int options;
98 int new_margin;
99
100 switch (cmd) {
101 case WDIOC_GETSUPPORT:
102 if (copy_to_user(argp, &info, sizeof(info)))
103 return -EFAULT;
104 break;
105
106 case WDIOC_GETSTATUS:
107 case WDIOC_GETBOOTSTATUS:
108 if (put_user(0, (int __user *)argp))
109 return -EFAULT;
110 break;
111
112 case WDIOC_KEEPALIVE:
113 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
114 break;
115
116 case WDIOC_SETOPTIONS:
117 if (copy_from_user(&options, argp, sizeof(options)))
118 return -EFAULT;
119
120 if (options & WDIOS_DISABLECARD)
121 riowd_writereg(p, 0, WDTO_INDEX);
122 else if (options & WDIOS_ENABLECARD)
123 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
124 else
125 return -EINVAL;
126
127 break;
128
129 case WDIOC_SETTIMEOUT:
130 if (get_user(new_margin, (int __user *)argp))
131 return -EFAULT;
132 if ((new_margin < 60) || (new_margin > (255 * 60)))
133 return -EINVAL;
134 riowd_timeout = (new_margin + 59) / 60;
135 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
136 fallthrough;
137
138 case WDIOC_GETTIMEOUT:
139 return put_user(riowd_timeout * 60, (int __user *)argp);
140
141 default:
142 return -EINVAL;
143 }
144
145 return 0;
146}
147
148static ssize_t riowd_write(struct file *file, const char __user *buf,
149 size_t count, loff_t *ppos)
150{
151 struct riowd *p = riowd_device;
152
153 if (count) {
154 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
155 return 1;
156 }
157
158 return 0;
159}
160
161static const struct file_operations riowd_fops = {
162 .owner = THIS_MODULE,
163 .llseek = no_llseek,
164 .unlocked_ioctl = riowd_ioctl,
165 .compat_ioctl = compat_ptr_ioctl,
166 .open = riowd_open,
167 .write = riowd_write,
168 .release = riowd_release,
169};
170
171static struct miscdevice riowd_miscdev = {
172 .minor = WATCHDOG_MINOR,
173 .name = "watchdog",
174 .fops = &riowd_fops
175};
176
177static 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 = devm_kzalloc(&op->dev, 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;
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 platform_set_drvdata(op, p);
210 return 0;
211
212out_iounmap:
213 riowd_device = NULL;
214 of_iounmap(&op->resource[0], p->regs, 2);
215
216out:
217 return err;
218}
219
220static void riowd_remove(struct platform_device *op)
221{
222 struct riowd *p = platform_get_drvdata(op);
223
224 misc_deregister(&riowd_miscdev);
225 of_iounmap(&op->resource[0], p->regs, 2);
226}
227
228static const struct of_device_id riowd_match[] = {
229 {
230 .name = "pmc",
231 },
232 {},
233};
234MODULE_DEVICE_TABLE(of, riowd_match);
235
236static struct platform_driver riowd_driver = {
237 .driver = {
238 .name = DRIVER_NAME,
239 .of_match_table = riowd_match,
240 },
241 .probe = riowd_probe,
242 .remove_new = riowd_remove,
243};
244
245module_platform_driver(riowd_driver);
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/miscdevice.h>
14#include <linux/watchdog.h>
15#include <linux/of.h>
16#include <linux/of_device.h>
17#include <linux/io.h>
18#include <linux/uaccess.h>
19#include <linux/slab.h>
20
21
22/* RIO uses the NatSemi Super I/O power management logical device
23 * as its' watchdog.
24 *
25 * When the watchdog triggers, it asserts a line to the BBC (Boot Bus
26 * Controller) of the machine. The BBC can only be configured to
27 * trigger a power-on reset when the signal is asserted. The BBC
28 * can be configured to ignore the signal entirely as well.
29 *
30 * The only Super I/O device register we care about is at index
31 * 0x05 (WDTO_INDEX) which is the watchdog time-out in minutes (1-255).
32 * If set to zero, this disables the watchdog. When set, the system
33 * must periodically (before watchdog expires) clear (set to zero) and
34 * re-set the watchdog else it will trigger.
35 *
36 * There are two other indexed watchdog registers inside this Super I/O
37 * logical device, but they are unused. The first, at index 0x06 is
38 * the watchdog control and can be used to make the watchdog timer re-set
39 * when the PS/2 mouse or serial lines show activity. The second, at
40 * index 0x07 is merely a sampling of the line from the watchdog to the
41 * BBC.
42 *
43 * The watchdog device generates no interrupts.
44 */
45
46MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
47MODULE_DESCRIPTION("Hardware watchdog driver for Sun RIO");
48MODULE_SUPPORTED_DEVICE("watchdog");
49MODULE_LICENSE("GPL");
50
51#define DRIVER_NAME "riowd"
52#define PFX DRIVER_NAME ": "
53
54struct riowd {
55 void __iomem *regs;
56 spinlock_t lock;
57};
58
59static struct riowd *riowd_device;
60
61#define WDTO_INDEX 0x05
62
63static int riowd_timeout = 1; /* in minutes */
64module_param(riowd_timeout, int, 0);
65MODULE_PARM_DESC(riowd_timeout, "Watchdog timeout in minutes");
66
67static void riowd_writereg(struct riowd *p, u8 val, int index)
68{
69 unsigned long flags;
70
71 spin_lock_irqsave(&p->lock, flags);
72 writeb(index, p->regs + 0);
73 writeb(val, p->regs + 1);
74 spin_unlock_irqrestore(&p->lock, flags);
75}
76
77static int riowd_open(struct inode *inode, struct file *filp)
78{
79 nonseekable_open(inode, filp);
80 return 0;
81}
82
83static int riowd_release(struct inode *inode, struct file *filp)
84{
85 return 0;
86}
87
88static long riowd_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
89{
90 static const struct watchdog_info info = {
91 .options = WDIOF_SETTIMEOUT,
92 .firmware_version = 1,
93 .identity = DRIVER_NAME,
94 };
95 void __user *argp = (void __user *)arg;
96 struct riowd *p = riowd_device;
97 unsigned int options;
98 int new_margin;
99
100 switch (cmd) {
101 case WDIOC_GETSUPPORT:
102 if (copy_to_user(argp, &info, sizeof(info)))
103 return -EFAULT;
104 break;
105
106 case WDIOC_GETSTATUS:
107 case WDIOC_GETBOOTSTATUS:
108 if (put_user(0, (int __user *)argp))
109 return -EFAULT;
110 break;
111
112 case WDIOC_KEEPALIVE:
113 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
114 break;
115
116 case WDIOC_SETOPTIONS:
117 if (copy_from_user(&options, argp, sizeof(options)))
118 return -EFAULT;
119
120 if (options & WDIOS_DISABLECARD)
121 riowd_writereg(p, 0, WDTO_INDEX);
122 else if (options & WDIOS_ENABLECARD)
123 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
124 else
125 return -EINVAL;
126
127 break;
128
129 case WDIOC_SETTIMEOUT:
130 if (get_user(new_margin, (int __user *)argp))
131 return -EFAULT;
132 if ((new_margin < 60) || (new_margin > (255 * 60)))
133 return -EINVAL;
134 riowd_timeout = (new_margin + 59) / 60;
135 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
136 /* Fall */
137
138 case WDIOC_GETTIMEOUT:
139 return put_user(riowd_timeout * 60, (int __user *)argp);
140
141 default:
142 return -EINVAL;
143 };
144
145 return 0;
146}
147
148static ssize_t riowd_write(struct file *file, const char __user *buf,
149 size_t count, loff_t *ppos)
150{
151 struct riowd *p = riowd_device;
152
153 if (count) {
154 riowd_writereg(p, riowd_timeout, WDTO_INDEX);
155 return 1;
156 }
157
158 return 0;
159}
160
161static const struct file_operations riowd_fops = {
162 .owner = THIS_MODULE,
163 .llseek = no_llseek,
164 .unlocked_ioctl = riowd_ioctl,
165 .open = riowd_open,
166 .write = riowd_write,
167 .release = riowd_release,
168};
169
170static struct miscdevice riowd_miscdev = {
171 .minor = WATCHDOG_MINOR,
172 .name = "watchdog",
173 .fops = &riowd_fops
174};
175
176static int riowd_probe(struct platform_device *op)
177{
178 struct riowd *p;
179 int err = -EINVAL;
180
181 if (riowd_device)
182 goto out;
183
184 err = -ENOMEM;
185 p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL);
186 if (!p)
187 goto out;
188
189 spin_lock_init(&p->lock);
190
191 p->regs = of_ioremap(&op->resource[0], 0, 2, DRIVER_NAME);
192 if (!p->regs) {
193 pr_err("Cannot map registers\n");
194 goto out;
195 }
196 /* Make miscdev useable right away */
197 riowd_device = p;
198
199 err = misc_register(&riowd_miscdev);
200 if (err) {
201 pr_err("Cannot register watchdog misc device\n");
202 goto out_iounmap;
203 }
204
205 pr_info("Hardware watchdog [%i minutes], regs at %p\n",
206 riowd_timeout, p->regs);
207
208 platform_set_drvdata(op, p);
209 return 0;
210
211out_iounmap:
212 riowd_device = NULL;
213 of_iounmap(&op->resource[0], p->regs, 2);
214
215out:
216 return err;
217}
218
219static int riowd_remove(struct platform_device *op)
220{
221 struct riowd *p = platform_get_drvdata(op);
222
223 misc_deregister(&riowd_miscdev);
224 of_iounmap(&op->resource[0], p->regs, 2);
225
226 return 0;
227}
228
229static const struct of_device_id riowd_match[] = {
230 {
231 .name = "pmc",
232 },
233 {},
234};
235MODULE_DEVICE_TABLE(of, riowd_match);
236
237static struct platform_driver riowd_driver = {
238 .driver = {
239 .name = DRIVER_NAME,
240 .owner = THIS_MODULE,
241 .of_match_table = riowd_match,
242 },
243 .probe = riowd_probe,
244 .remove = riowd_remove,
245};
246
247module_platform_driver(riowd_driver);