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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * PNX833x Hardware Watchdog Driver
4 * Copyright 2008 NXP Semiconductors
5 * Daniel Laird <daniel.j.laird@nxp.com>
6 * Andre McCurdy <andre.mccurdy@nxp.com>
7 *
8 * Heavily based upon - IndyDog 0.3
9 * A Hardware Watchdog Device for SGI IP22
10 *
11 * (c) Copyright 2002 Guido Guenther <agx@sigxcpu.org>, All Rights Reserved.
12 *
13 * based on softdog.c by Alan Cox <alan@redhat.com>
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/types.h>
21#include <linux/kernel.h>
22#include <linux/fs.h>
23#include <linux/mm.h>
24#include <linux/miscdevice.h>
25#include <linux/watchdog.h>
26#include <linux/notifier.h>
27#include <linux/reboot.h>
28#include <linux/init.h>
29#include <asm/mach-pnx833x/pnx833x.h>
30
31#define WATCHDOG_TIMEOUT 30 /* 30 sec Maximum timeout */
32#define WATCHDOG_COUNT_FREQUENCY 68000000U /* Watchdog counts at 68MHZ. */
33#define PNX_WATCHDOG_TIMEOUT (WATCHDOG_TIMEOUT * WATCHDOG_COUNT_FREQUENCY)
34#define PNX_TIMEOUT_VALUE 2040000000U
35
36/** CONFIG block */
37#define PNX833X_CONFIG (0x07000U)
38#define PNX833X_CONFIG_CPU_WATCHDOG (0x54)
39#define PNX833X_CONFIG_CPU_WATCHDOG_COMPARE (0x58)
40#define PNX833X_CONFIG_CPU_COUNTERS_CONTROL (0x1c)
41
42/** RESET block */
43#define PNX833X_RESET (0x08000U)
44#define PNX833X_RESET_CONFIG (0x08)
45
46static int pnx833x_wdt_alive;
47
48/* Set default timeout in MHZ.*/
49static int pnx833x_wdt_timeout = PNX_WATCHDOG_TIMEOUT;
50module_param(pnx833x_wdt_timeout, int, 0);
51MODULE_PARM_DESC(timeout, "Watchdog timeout in Mhz. (68Mhz clock), default="
52 __MODULE_STRING(PNX_TIMEOUT_VALUE) "(30 seconds).");
53
54static bool nowayout = WATCHDOG_NOWAYOUT;
55module_param(nowayout, bool, 0);
56MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
57 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
58
59#define START_DEFAULT 1
60static int start_enabled = START_DEFAULT;
61module_param(start_enabled, int, 0);
62MODULE_PARM_DESC(start_enabled, "Watchdog is started on module insertion "
63 "(default=" __MODULE_STRING(START_DEFAULT) ")");
64
65static void pnx833x_wdt_start(void)
66{
67 /* Enable watchdog causing reset. */
68 PNX833X_REG(PNX833X_RESET + PNX833X_RESET_CONFIG) |= 0x1;
69 /* Set timeout.*/
70 PNX833X_REG(PNX833X_CONFIG +
71 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
72 /* Enable watchdog. */
73 PNX833X_REG(PNX833X_CONFIG +
74 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) |= 0x1;
75
76 pr_info("Started watchdog timer\n");
77}
78
79static void pnx833x_wdt_stop(void)
80{
81 /* Disable watchdog causing reset. */
82 PNX833X_REG(PNX833X_RESET + PNX833X_CONFIG) &= 0xFFFFFFFE;
83 /* Disable watchdog.*/
84 PNX833X_REG(PNX833X_CONFIG +
85 PNX833X_CONFIG_CPU_COUNTERS_CONTROL) &= 0xFFFFFFFE;
86
87 pr_info("Stopped watchdog timer\n");
88}
89
90static void pnx833x_wdt_ping(void)
91{
92 PNX833X_REG(PNX833X_CONFIG +
93 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = pnx833x_wdt_timeout;
94}
95
96/*
97 * Allow only one person to hold it open
98 */
99static int pnx833x_wdt_open(struct inode *inode, struct file *file)
100{
101 if (test_and_set_bit(0, &pnx833x_wdt_alive))
102 return -EBUSY;
103
104 if (nowayout)
105 __module_get(THIS_MODULE);
106
107 /* Activate timer */
108 if (!start_enabled)
109 pnx833x_wdt_start();
110
111 pnx833x_wdt_ping();
112
113 pr_info("Started watchdog timer\n");
114
115 return stream_open(inode, file);
116}
117
118static int pnx833x_wdt_release(struct inode *inode, struct file *file)
119{
120 /* Shut off the timer.
121 * Lock it in if it's a module and we defined ...NOWAYOUT */
122 if (!nowayout)
123 pnx833x_wdt_stop(); /* Turn the WDT off */
124
125 clear_bit(0, &pnx833x_wdt_alive);
126 return 0;
127}
128
129static ssize_t pnx833x_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
130{
131 /* Refresh the timer. */
132 if (len)
133 pnx833x_wdt_ping();
134
135 return len;
136}
137
138static long pnx833x_wdt_ioctl(struct file *file, unsigned int cmd,
139 unsigned long arg)
140{
141 int options, new_timeout = 0;
142 uint32_t timeout, timeout_left = 0;
143
144 static const struct watchdog_info ident = {
145 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT,
146 .firmware_version = 0,
147 .identity = "Hardware Watchdog for PNX833x",
148 };
149
150 switch (cmd) {
151 default:
152 return -ENOTTY;
153
154 case WDIOC_GETSUPPORT:
155 if (copy_to_user((struct watchdog_info *)arg,
156 &ident, sizeof(ident)))
157 return -EFAULT;
158 return 0;
159
160 case WDIOC_GETSTATUS:
161 case WDIOC_GETBOOTSTATUS:
162 return put_user(0, (int *)arg);
163
164 case WDIOC_SETOPTIONS:
165 if (get_user(options, (int *)arg))
166 return -EFAULT;
167
168 if (options & WDIOS_DISABLECARD)
169 pnx833x_wdt_stop();
170
171 if (options & WDIOS_ENABLECARD)
172 pnx833x_wdt_start();
173
174 return 0;
175
176 case WDIOC_KEEPALIVE:
177 pnx833x_wdt_ping();
178 return 0;
179
180 case WDIOC_SETTIMEOUT:
181 {
182 if (get_user(new_timeout, (int *)arg))
183 return -EFAULT;
184
185 pnx833x_wdt_timeout = new_timeout;
186 PNX833X_REG(PNX833X_CONFIG +
187 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE) = new_timeout;
188 return put_user(new_timeout, (int *)arg);
189 }
190
191 case WDIOC_GETTIMEOUT:
192 timeout = PNX833X_REG(PNX833X_CONFIG +
193 PNX833X_CONFIG_CPU_WATCHDOG_COMPARE);
194 return put_user(timeout, (int *)arg);
195
196 case WDIOC_GETTIMELEFT:
197 timeout_left = PNX833X_REG(PNX833X_CONFIG +
198 PNX833X_CONFIG_CPU_WATCHDOG);
199 return put_user(timeout_left, (int *)arg);
200
201 }
202}
203
204static int pnx833x_wdt_notify_sys(struct notifier_block *this,
205 unsigned long code, void *unused)
206{
207 if (code == SYS_DOWN || code == SYS_HALT)
208 pnx833x_wdt_stop(); /* Turn the WDT off */
209
210 return NOTIFY_DONE;
211}
212
213static const struct file_operations pnx833x_wdt_fops = {
214 .owner = THIS_MODULE,
215 .llseek = no_llseek,
216 .write = pnx833x_wdt_write,
217 .unlocked_ioctl = pnx833x_wdt_ioctl,
218 .compat_ioctl = compat_ptr_ioctl,
219 .open = pnx833x_wdt_open,
220 .release = pnx833x_wdt_release,
221};
222
223static struct miscdevice pnx833x_wdt_miscdev = {
224 .minor = WATCHDOG_MINOR,
225 .name = "watchdog",
226 .fops = &pnx833x_wdt_fops,
227};
228
229static struct notifier_block pnx833x_wdt_notifier = {
230 .notifier_call = pnx833x_wdt_notify_sys,
231};
232
233static int __init watchdog_init(void)
234{
235 int ret, cause;
236
237 /* Lets check the reason for the reset.*/
238 cause = PNX833X_REG(PNX833X_RESET);
239 /*If bit 31 is set then watchdog was cause of reset.*/
240 if (cause & 0x80000000) {
241 pr_info("The system was previously reset due to the watchdog firing - please investigate...\n");
242 }
243
244 ret = register_reboot_notifier(&pnx833x_wdt_notifier);
245 if (ret) {
246 pr_err("cannot register reboot notifier (err=%d)\n", ret);
247 return ret;
248 }
249
250 ret = misc_register(&pnx833x_wdt_miscdev);
251 if (ret) {
252 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
253 WATCHDOG_MINOR, ret);
254 unregister_reboot_notifier(&pnx833x_wdt_notifier);
255 return ret;
256 }
257
258 pr_info("Hardware Watchdog Timer for PNX833x: Version 0.1\n");
259
260 if (start_enabled)
261 pnx833x_wdt_start();
262
263 return 0;
264}
265
266static void __exit watchdog_exit(void)
267{
268 misc_deregister(&pnx833x_wdt_miscdev);
269 unregister_reboot_notifier(&pnx833x_wdt_notifier);
270}
271
272module_init(watchdog_init);
273module_exit(watchdog_exit);
274
275MODULE_AUTHOR("Daniel Laird/Andre McCurdy");
276MODULE_DESCRIPTION("Hardware Watchdog Device for PNX833x");
277MODULE_LICENSE("GPL");