Loading...
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * drivers/watchdog/ar7_wdt.c
4 *
5 * Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
6 * Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
7 *
8 * Some code taken from:
9 * National Semiconductor SCx200 Watchdog support
10 * Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
11 *
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/errno.h>
19#include <linux/miscdevice.h>
20#include <linux/platform_device.h>
21#include <linux/watchdog.h>
22#include <linux/fs.h>
23#include <linux/ioport.h>
24#include <linux/io.h>
25#include <linux/uaccess.h>
26#include <linux/clk.h>
27
28#include <asm/addrspace.h>
29#include <asm/mach-ar7/ar7.h>
30
31#define LONGNAME "TI AR7 Watchdog Timer"
32
33MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
34MODULE_DESCRIPTION(LONGNAME);
35MODULE_LICENSE("GPL");
36
37static int margin = 60;
38module_param(margin, int, 0);
39MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
40
41static bool nowayout = WATCHDOG_NOWAYOUT;
42module_param(nowayout, bool, 0);
43MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
44
45#define READ_REG(x) readl((void __iomem *)&(x))
46#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
47
48struct ar7_wdt {
49 u32 kick_lock;
50 u32 kick;
51 u32 change_lock;
52 u32 change;
53 u32 disable_lock;
54 u32 disable;
55 u32 prescale_lock;
56 u32 prescale;
57};
58
59static unsigned long wdt_is_open;
60static unsigned expect_close;
61static DEFINE_SPINLOCK(wdt_lock);
62
63/* XXX currently fixed, allows max margin ~68.72 secs */
64#define prescale_value 0xffff
65
66/* Pointer to the remapped WDT IO space */
67static struct ar7_wdt *ar7_wdt;
68
69static struct clk *vbus_clk;
70
71static void ar7_wdt_kick(u32 value)
72{
73 WRITE_REG(ar7_wdt->kick_lock, 0x5555);
74 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
75 WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
76 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
77 WRITE_REG(ar7_wdt->kick, value);
78 return;
79 }
80 }
81 pr_err("failed to unlock WDT kick reg\n");
82}
83
84static void ar7_wdt_prescale(u32 value)
85{
86 WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
87 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
88 WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
89 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
90 WRITE_REG(ar7_wdt->prescale, value);
91 return;
92 }
93 }
94 pr_err("failed to unlock WDT prescale reg\n");
95}
96
97static void ar7_wdt_change(u32 value)
98{
99 WRITE_REG(ar7_wdt->change_lock, 0x6666);
100 if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
101 WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
102 if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
103 WRITE_REG(ar7_wdt->change, value);
104 return;
105 }
106 }
107 pr_err("failed to unlock WDT change reg\n");
108}
109
110static void ar7_wdt_disable(u32 value)
111{
112 WRITE_REG(ar7_wdt->disable_lock, 0x7777);
113 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
114 WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
115 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
116 WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
117 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
118 WRITE_REG(ar7_wdt->disable, value);
119 return;
120 }
121 }
122 }
123 pr_err("failed to unlock WDT disable reg\n");
124}
125
126static void ar7_wdt_update_margin(int new_margin)
127{
128 u32 change;
129 u32 vbus_rate;
130
131 vbus_rate = clk_get_rate(vbus_clk);
132 change = new_margin * (vbus_rate / prescale_value);
133 if (change < 1)
134 change = 1;
135 if (change > 0xffff)
136 change = 0xffff;
137 ar7_wdt_change(change);
138 margin = change * prescale_value / vbus_rate;
139 pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n",
140 margin, prescale_value, change, vbus_rate);
141}
142
143static void ar7_wdt_enable_wdt(void)
144{
145 pr_debug("enabling watchdog timer\n");
146 ar7_wdt_disable(1);
147 ar7_wdt_kick(1);
148}
149
150static void ar7_wdt_disable_wdt(void)
151{
152 pr_debug("disabling watchdog timer\n");
153 ar7_wdt_disable(0);
154}
155
156static int ar7_wdt_open(struct inode *inode, struct file *file)
157{
158 /* only allow one at a time */
159 if (test_and_set_bit(0, &wdt_is_open))
160 return -EBUSY;
161 ar7_wdt_enable_wdt();
162 expect_close = 0;
163
164 return stream_open(inode, file);
165}
166
167static int ar7_wdt_release(struct inode *inode, struct file *file)
168{
169 if (!expect_close)
170 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
171 else if (!nowayout)
172 ar7_wdt_disable_wdt();
173 clear_bit(0, &wdt_is_open);
174 return 0;
175}
176
177static ssize_t ar7_wdt_write(struct file *file, const char *data,
178 size_t len, loff_t *ppos)
179{
180 /* check for a magic close character */
181 if (len) {
182 size_t i;
183
184 spin_lock(&wdt_lock);
185 ar7_wdt_kick(1);
186 spin_unlock(&wdt_lock);
187
188 expect_close = 0;
189 for (i = 0; i < len; ++i) {
190 char c;
191 if (get_user(c, data + i))
192 return -EFAULT;
193 if (c == 'V')
194 expect_close = 1;
195 }
196
197 }
198 return len;
199}
200
201static long ar7_wdt_ioctl(struct file *file,
202 unsigned int cmd, unsigned long arg)
203{
204 static const struct watchdog_info ident = {
205 .identity = LONGNAME,
206 .firmware_version = 1,
207 .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
208 WDIOF_MAGICCLOSE),
209 };
210 int new_margin;
211
212 switch (cmd) {
213 case WDIOC_GETSUPPORT:
214 if (copy_to_user((struct watchdog_info *)arg, &ident,
215 sizeof(ident)))
216 return -EFAULT;
217 return 0;
218 case WDIOC_GETSTATUS:
219 case WDIOC_GETBOOTSTATUS:
220 if (put_user(0, (int *)arg))
221 return -EFAULT;
222 return 0;
223 case WDIOC_KEEPALIVE:
224 ar7_wdt_kick(1);
225 return 0;
226 case WDIOC_SETTIMEOUT:
227 if (get_user(new_margin, (int *)arg))
228 return -EFAULT;
229 if (new_margin < 1)
230 return -EINVAL;
231
232 spin_lock(&wdt_lock);
233 ar7_wdt_update_margin(new_margin);
234 ar7_wdt_kick(1);
235 spin_unlock(&wdt_lock);
236 fallthrough;
237 case WDIOC_GETTIMEOUT:
238 if (put_user(margin, (int *)arg))
239 return -EFAULT;
240 return 0;
241 default:
242 return -ENOTTY;
243 }
244}
245
246static const struct file_operations ar7_wdt_fops = {
247 .owner = THIS_MODULE,
248 .write = ar7_wdt_write,
249 .unlocked_ioctl = ar7_wdt_ioctl,
250 .compat_ioctl = compat_ptr_ioctl,
251 .open = ar7_wdt_open,
252 .release = ar7_wdt_release,
253 .llseek = no_llseek,
254};
255
256static struct miscdevice ar7_wdt_miscdev = {
257 .minor = WATCHDOG_MINOR,
258 .name = "watchdog",
259 .fops = &ar7_wdt_fops,
260};
261
262static int ar7_wdt_probe(struct platform_device *pdev)
263{
264 int rc;
265
266 ar7_wdt = devm_platform_ioremap_resource_byname(pdev, "regs");
267 if (IS_ERR(ar7_wdt))
268 return PTR_ERR(ar7_wdt);
269
270 vbus_clk = clk_get(NULL, "vbus");
271 if (IS_ERR(vbus_clk)) {
272 pr_err("could not get vbus clock\n");
273 return PTR_ERR(vbus_clk);
274 }
275
276 ar7_wdt_disable_wdt();
277 ar7_wdt_prescale(prescale_value);
278 ar7_wdt_update_margin(margin);
279
280 rc = misc_register(&ar7_wdt_miscdev);
281 if (rc) {
282 pr_err("unable to register misc device\n");
283 goto out;
284 }
285 return 0;
286
287out:
288 clk_put(vbus_clk);
289 vbus_clk = NULL;
290 return rc;
291}
292
293static int ar7_wdt_remove(struct platform_device *pdev)
294{
295 misc_deregister(&ar7_wdt_miscdev);
296 clk_put(vbus_clk);
297 vbus_clk = NULL;
298 return 0;
299}
300
301static void ar7_wdt_shutdown(struct platform_device *pdev)
302{
303 if (!nowayout)
304 ar7_wdt_disable_wdt();
305}
306
307static struct platform_driver ar7_wdt_driver = {
308 .probe = ar7_wdt_probe,
309 .remove = ar7_wdt_remove,
310 .shutdown = ar7_wdt_shutdown,
311 .driver = {
312 .name = "ar7_wdt",
313 },
314};
315
316module_platform_driver(ar7_wdt_driver);
1/*
2 * drivers/watchdog/ar7_wdt.c
3 *
4 * Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
5 * Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
6 *
7 * Some code taken from:
8 * National Semiconductor SCx200 Watchdog support
9 * Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
24 */
25
26#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27
28#include <linux/module.h>
29#include <linux/moduleparam.h>
30#include <linux/errno.h>
31#include <linux/miscdevice.h>
32#include <linux/platform_device.h>
33#include <linux/watchdog.h>
34#include <linux/fs.h>
35#include <linux/ioport.h>
36#include <linux/io.h>
37#include <linux/uaccess.h>
38#include <linux/clk.h>
39
40#include <asm/addrspace.h>
41#include <asm/mach-ar7/ar7.h>
42
43#define LONGNAME "TI AR7 Watchdog Timer"
44
45MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
46MODULE_DESCRIPTION(LONGNAME);
47MODULE_LICENSE("GPL");
48
49static int margin = 60;
50module_param(margin, int, 0);
51MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
52
53static bool nowayout = WATCHDOG_NOWAYOUT;
54module_param(nowayout, bool, 0);
55MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
56
57#define READ_REG(x) readl((void __iomem *)&(x))
58#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
59
60struct ar7_wdt {
61 u32 kick_lock;
62 u32 kick;
63 u32 change_lock;
64 u32 change;
65 u32 disable_lock;
66 u32 disable;
67 u32 prescale_lock;
68 u32 prescale;
69};
70
71static unsigned long wdt_is_open;
72static unsigned expect_close;
73static DEFINE_SPINLOCK(wdt_lock);
74
75/* XXX currently fixed, allows max margin ~68.72 secs */
76#define prescale_value 0xffff
77
78/* Resource of the WDT registers */
79static struct resource *ar7_regs_wdt;
80/* Pointer to the remapped WDT IO space */
81static struct ar7_wdt *ar7_wdt;
82
83static struct clk *vbus_clk;
84
85static void ar7_wdt_kick(u32 value)
86{
87 WRITE_REG(ar7_wdt->kick_lock, 0x5555);
88 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
89 WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
90 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
91 WRITE_REG(ar7_wdt->kick, value);
92 return;
93 }
94 }
95 pr_err("failed to unlock WDT kick reg\n");
96}
97
98static void ar7_wdt_prescale(u32 value)
99{
100 WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
101 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
102 WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
103 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
104 WRITE_REG(ar7_wdt->prescale, value);
105 return;
106 }
107 }
108 pr_err("failed to unlock WDT prescale reg\n");
109}
110
111static void ar7_wdt_change(u32 value)
112{
113 WRITE_REG(ar7_wdt->change_lock, 0x6666);
114 if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
115 WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
116 if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
117 WRITE_REG(ar7_wdt->change, value);
118 return;
119 }
120 }
121 pr_err("failed to unlock WDT change reg\n");
122}
123
124static void ar7_wdt_disable(u32 value)
125{
126 WRITE_REG(ar7_wdt->disable_lock, 0x7777);
127 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
128 WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
129 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
130 WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
131 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
132 WRITE_REG(ar7_wdt->disable, value);
133 return;
134 }
135 }
136 }
137 pr_err("failed to unlock WDT disable reg\n");
138}
139
140static void ar7_wdt_update_margin(int new_margin)
141{
142 u32 change;
143 u32 vbus_rate;
144
145 vbus_rate = clk_get_rate(vbus_clk);
146 change = new_margin * (vbus_rate / prescale_value);
147 if (change < 1)
148 change = 1;
149 if (change > 0xffff)
150 change = 0xffff;
151 ar7_wdt_change(change);
152 margin = change * prescale_value / vbus_rate;
153 pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n",
154 margin, prescale_value, change, vbus_rate);
155}
156
157static void ar7_wdt_enable_wdt(void)
158{
159 pr_debug("enabling watchdog timer\n");
160 ar7_wdt_disable(1);
161 ar7_wdt_kick(1);
162}
163
164static void ar7_wdt_disable_wdt(void)
165{
166 pr_debug("disabling watchdog timer\n");
167 ar7_wdt_disable(0);
168}
169
170static int ar7_wdt_open(struct inode *inode, struct file *file)
171{
172 /* only allow one at a time */
173 if (test_and_set_bit(0, &wdt_is_open))
174 return -EBUSY;
175 ar7_wdt_enable_wdt();
176 expect_close = 0;
177
178 return nonseekable_open(inode, file);
179}
180
181static int ar7_wdt_release(struct inode *inode, struct file *file)
182{
183 if (!expect_close)
184 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
185 else if (!nowayout)
186 ar7_wdt_disable_wdt();
187 clear_bit(0, &wdt_is_open);
188 return 0;
189}
190
191static ssize_t ar7_wdt_write(struct file *file, const char *data,
192 size_t len, loff_t *ppos)
193{
194 /* check for a magic close character */
195 if (len) {
196 size_t i;
197
198 spin_lock(&wdt_lock);
199 ar7_wdt_kick(1);
200 spin_unlock(&wdt_lock);
201
202 expect_close = 0;
203 for (i = 0; i < len; ++i) {
204 char c;
205 if (get_user(c, data + i))
206 return -EFAULT;
207 if (c == 'V')
208 expect_close = 1;
209 }
210
211 }
212 return len;
213}
214
215static long ar7_wdt_ioctl(struct file *file,
216 unsigned int cmd, unsigned long arg)
217{
218 static const struct watchdog_info ident = {
219 .identity = LONGNAME,
220 .firmware_version = 1,
221 .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
222 WDIOF_MAGICCLOSE),
223 };
224 int new_margin;
225
226 switch (cmd) {
227 case WDIOC_GETSUPPORT:
228 if (copy_to_user((struct watchdog_info *)arg, &ident,
229 sizeof(ident)))
230 return -EFAULT;
231 return 0;
232 case WDIOC_GETSTATUS:
233 case WDIOC_GETBOOTSTATUS:
234 if (put_user(0, (int *)arg))
235 return -EFAULT;
236 return 0;
237 case WDIOC_KEEPALIVE:
238 ar7_wdt_kick(1);
239 return 0;
240 case WDIOC_SETTIMEOUT:
241 if (get_user(new_margin, (int *)arg))
242 return -EFAULT;
243 if (new_margin < 1)
244 return -EINVAL;
245
246 spin_lock(&wdt_lock);
247 ar7_wdt_update_margin(new_margin);
248 ar7_wdt_kick(1);
249 spin_unlock(&wdt_lock);
250
251 case WDIOC_GETTIMEOUT:
252 if (put_user(margin, (int *)arg))
253 return -EFAULT;
254 return 0;
255 default:
256 return -ENOTTY;
257 }
258}
259
260static const struct file_operations ar7_wdt_fops = {
261 .owner = THIS_MODULE,
262 .write = ar7_wdt_write,
263 .unlocked_ioctl = ar7_wdt_ioctl,
264 .open = ar7_wdt_open,
265 .release = ar7_wdt_release,
266 .llseek = no_llseek,
267};
268
269static struct miscdevice ar7_wdt_miscdev = {
270 .minor = WATCHDOG_MINOR,
271 .name = "watchdog",
272 .fops = &ar7_wdt_fops,
273};
274
275static int ar7_wdt_probe(struct platform_device *pdev)
276{
277 int rc;
278
279 ar7_regs_wdt =
280 platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
281 ar7_wdt = devm_ioremap_resource(&pdev->dev, ar7_regs_wdt);
282 if (IS_ERR(ar7_wdt))
283 return PTR_ERR(ar7_wdt);
284
285 vbus_clk = clk_get(NULL, "vbus");
286 if (IS_ERR(vbus_clk)) {
287 pr_err("could not get vbus clock\n");
288 return PTR_ERR(vbus_clk);
289 }
290
291 ar7_wdt_disable_wdt();
292 ar7_wdt_prescale(prescale_value);
293 ar7_wdt_update_margin(margin);
294
295 rc = misc_register(&ar7_wdt_miscdev);
296 if (rc) {
297 pr_err("unable to register misc device\n");
298 goto out;
299 }
300 return 0;
301
302out:
303 clk_put(vbus_clk);
304 vbus_clk = NULL;
305 return rc;
306}
307
308static int ar7_wdt_remove(struct platform_device *pdev)
309{
310 misc_deregister(&ar7_wdt_miscdev);
311 clk_put(vbus_clk);
312 vbus_clk = NULL;
313 return 0;
314}
315
316static void ar7_wdt_shutdown(struct platform_device *pdev)
317{
318 if (!nowayout)
319 ar7_wdt_disable_wdt();
320}
321
322static struct platform_driver ar7_wdt_driver = {
323 .probe = ar7_wdt_probe,
324 .remove = ar7_wdt_remove,
325 .shutdown = ar7_wdt_shutdown,
326 .driver = {
327 .name = "ar7_wdt",
328 },
329};
330
331module_platform_driver(ar7_wdt_driver);