tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
3 *
4 * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
5 * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
6 *
7 * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
8 * Author: Deepak Saxena <dsaxena@plexity.net>
9 * Copyright 2004 (c) MontaVista, Software, Inc.
10 *
11 * which again was based on sa1100 driver,
12 * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
13 *
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License version 2 as published
16 * by the Free Software Foundation.
17 *
18 */
19
20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21
22#include <linux/bitops.h>
23#include <linux/errno.h>
24#include <linux/fs.h>
25#include <linux/init.h>
26#include <linux/io.h>
27#include <linux/kernel.h>
28#include <linux/miscdevice.h>
29#include <linux/module.h>
30#include <linux/moduleparam.h>
31#include <linux/platform_device.h>
32#include <linux/types.h>
33#include <linux/watchdog.h>
34#include <linux/clk.h>
35#include <linux/err.h>
36#include <linux/of.h>
37#include <linux/of_platform.h>
38
39#define DRIVER_NAME "ath79-wdt"
40
41#define WDT_TIMEOUT 15 /* seconds */
42
43#define WDOG_REG_CTRL 0x00
44#define WDOG_REG_TIMER 0x04
45
46#define WDOG_CTRL_LAST_RESET BIT(31)
47#define WDOG_CTRL_ACTION_MASK 3
48#define WDOG_CTRL_ACTION_NONE 0 /* no action */
49#define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */
50#define WDOG_CTRL_ACTION_NMI 2 /* NMI */
51#define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */
52
53static bool nowayout = WATCHDOG_NOWAYOUT;
54module_param(nowayout, bool, 0);
55MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
56 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
57
58static int timeout = WDT_TIMEOUT;
59module_param(timeout, int, 0);
60MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
61 "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
62
63static unsigned long wdt_flags;
64
65#define WDT_FLAGS_BUSY 0
66#define WDT_FLAGS_EXPECT_CLOSE 1
67
68static struct clk *wdt_clk;
69static unsigned long wdt_freq;
70static int boot_status;
71static int max_timeout;
72static void __iomem *wdt_base;
73
74static inline void ath79_wdt_wr(unsigned reg, u32 val)
75{
76 iowrite32(val, wdt_base + reg);
77}
78
79static inline u32 ath79_wdt_rr(unsigned reg)
80{
81 return ioread32(wdt_base + reg);
82}
83
84static inline void ath79_wdt_keepalive(void)
85{
86 ath79_wdt_wr(WDOG_REG_TIMER, wdt_freq * timeout);
87 /* flush write */
88 ath79_wdt_rr(WDOG_REG_TIMER);
89}
90
91static inline void ath79_wdt_enable(void)
92{
93 ath79_wdt_keepalive();
94 ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_FCR);
95 /* flush write */
96 ath79_wdt_rr(WDOG_REG_CTRL);
97}
98
99static inline void ath79_wdt_disable(void)
100{
101 ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_NONE);
102 /* flush write */
103 ath79_wdt_rr(WDOG_REG_CTRL);
104}
105
106static int ath79_wdt_set_timeout(int val)
107{
108 if (val < 1 || val > max_timeout)
109 return -EINVAL;
110
111 timeout = val;
112 ath79_wdt_keepalive();
113
114 return 0;
115}
116
117static int ath79_wdt_open(struct inode *inode, struct file *file)
118{
119 if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
120 return -EBUSY;
121
122 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
123 ath79_wdt_enable();
124
125 return nonseekable_open(inode, file);
126}
127
128static int ath79_wdt_release(struct inode *inode, struct file *file)
129{
130 if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
131 ath79_wdt_disable();
132 else {
133 pr_crit("device closed unexpectedly, watchdog timer will not stop!\n");
134 ath79_wdt_keepalive();
135 }
136
137 clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
138 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
139
140 return 0;
141}
142
143static ssize_t ath79_wdt_write(struct file *file, const char *data,
144 size_t len, loff_t *ppos)
145{
146 if (len) {
147 if (!nowayout) {
148 size_t i;
149
150 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
151
152 for (i = 0; i != len; i++) {
153 char c;
154
155 if (get_user(c, data + i))
156 return -EFAULT;
157
158 if (c == 'V')
159 set_bit(WDT_FLAGS_EXPECT_CLOSE,
160 &wdt_flags);
161 }
162 }
163
164 ath79_wdt_keepalive();
165 }
166
167 return len;
168}
169
170static const struct watchdog_info ath79_wdt_info = {
171 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
172 WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
173 .firmware_version = 0,
174 .identity = "ATH79 watchdog",
175};
176
177static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
178 unsigned long arg)
179{
180 void __user *argp = (void __user *)arg;
181 int __user *p = argp;
182 int err;
183 int t;
184
185 switch (cmd) {
186 case WDIOC_GETSUPPORT:
187 err = copy_to_user(argp, &ath79_wdt_info,
188 sizeof(ath79_wdt_info)) ? -EFAULT : 0;
189 break;
190
191 case WDIOC_GETSTATUS:
192 err = put_user(0, p);
193 break;
194
195 case WDIOC_GETBOOTSTATUS:
196 err = put_user(boot_status, p);
197 break;
198
199 case WDIOC_KEEPALIVE:
200 ath79_wdt_keepalive();
201 err = 0;
202 break;
203
204 case WDIOC_SETTIMEOUT:
205 err = get_user(t, p);
206 if (err)
207 break;
208
209 err = ath79_wdt_set_timeout(t);
210 if (err)
211 break;
212
213 /* fallthrough */
214 case WDIOC_GETTIMEOUT:
215 err = put_user(timeout, p);
216 break;
217
218 default:
219 err = -ENOTTY;
220 break;
221 }
222
223 return err;
224}
225
226static const struct file_operations ath79_wdt_fops = {
227 .owner = THIS_MODULE,
228 .llseek = no_llseek,
229 .write = ath79_wdt_write,
230 .unlocked_ioctl = ath79_wdt_ioctl,
231 .open = ath79_wdt_open,
232 .release = ath79_wdt_release,
233};
234
235static struct miscdevice ath79_wdt_miscdev = {
236 .minor = WATCHDOG_MINOR,
237 .name = "watchdog",
238 .fops = &ath79_wdt_fops,
239};
240
241static int ath79_wdt_probe(struct platform_device *pdev)
242{
243 struct resource *res;
244 u32 ctrl;
245 int err;
246
247 if (wdt_base)
248 return -EBUSY;
249
250 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
251 if (!res) {
252 dev_err(&pdev->dev, "no memory resource found\n");
253 return -EINVAL;
254 }
255
256 wdt_base = devm_request_and_ioremap(&pdev->dev, res);
257 if (!wdt_base) {
258 dev_err(&pdev->dev, "unable to remap memory region\n");
259 return -ENOMEM;
260 }
261
262 wdt_clk = devm_clk_get(&pdev->dev, "wdt");
263 if (IS_ERR(wdt_clk))
264 return PTR_ERR(wdt_clk);
265
266 err = clk_enable(wdt_clk);
267 if (err)
268 return err;
269
270 wdt_freq = clk_get_rate(wdt_clk);
271 if (!wdt_freq) {
272 err = -EINVAL;
273 goto err_clk_disable;
274 }
275
276 max_timeout = (0xfffffffful / wdt_freq);
277 if (timeout < 1 || timeout > max_timeout) {
278 timeout = max_timeout;
279 dev_info(&pdev->dev,
280 "timeout value must be 0 < timeout < %d, using %d\n",
281 max_timeout, timeout);
282 }
283
284 ctrl = ath79_wdt_rr(WDOG_REG_CTRL);
285 boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
286
287 err = misc_register(&ath79_wdt_miscdev);
288 if (err) {
289 dev_err(&pdev->dev,
290 "unable to register misc device, err=%d\n", err);
291 goto err_clk_disable;
292 }
293
294 return 0;
295
296err_clk_disable:
297 clk_disable(wdt_clk);
298 return err;
299}
300
301static int ath79_wdt_remove(struct platform_device *pdev)
302{
303 misc_deregister(&ath79_wdt_miscdev);
304 clk_disable(wdt_clk);
305 return 0;
306}
307
308static void ath97_wdt_shutdown(struct platform_device *pdev)
309{
310 ath79_wdt_disable();
311}
312
313#ifdef CONFIG_OF
314static const struct of_device_id ath79_wdt_match[] = {
315 { .compatible = "qca,ar7130-wdt" },
316 {},
317};
318MODULE_DEVICE_TABLE(of, ath79_wdt_match);
319#endif
320
321static struct platform_driver ath79_wdt_driver = {
322 .probe = ath79_wdt_probe,
323 .remove = ath79_wdt_remove,
324 .shutdown = ath97_wdt_shutdown,
325 .driver = {
326 .name = DRIVER_NAME,
327 .owner = THIS_MODULE,
328 .of_match_table = of_match_ptr(ath79_wdt_match),
329 },
330};
331
332module_platform_driver(ath79_wdt_driver);
333
334MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
335MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
336MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
337MODULE_LICENSE("GPL v2");
338MODULE_ALIAS("platform:" DRIVER_NAME);
339MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);