blob: 6eb91d75760466e83e983ad3875973f4cf8c3264 [file] [log] [blame]
Marc Zyngier66aaa7a2010-02-04 20:08:56 +00001/*
2 * drivers/char/watchdog/max63xx_wdt.c
3 *
4 * Driver for max63{69,70,71,72,73,74} watchdog timers
5 *
6 * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
7 *
8 * This file is licensed under the terms of the GNU General Public
9 * License version 2. This program is licensed "as is" without any
10 * warranty of any kind, whether express or implied.
11 *
12 * This driver assumes the watchdog pins are memory mapped (as it is
13 * the case for the Arcom Zeus). Should it be connected over GPIOs or
14 * another interface, some abstraction will have to be introduced.
15 */
16
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/types.h>
20#include <linux/kernel.h>
21#include <linux/fs.h>
22#include <linux/miscdevice.h>
23#include <linux/watchdog.h>
24#include <linux/init.h>
25#include <linux/bitops.h>
26#include <linux/platform_device.h>
27#include <linux/spinlock.h>
28#include <linux/uaccess.h>
29#include <linux/io.h>
30#include <linux/device.h>
31
32#define DEFAULT_HEARTBEAT 60
33#define MAX_HEARTBEAT 60
34
35static int heartbeat = DEFAULT_HEARTBEAT;
36static int nowayout = WATCHDOG_NOWAYOUT;
37
38/*
39 * Memory mapping: a single byte, 3 first lower bits to select bit 3
40 * to ping the watchdog.
41 */
42#define MAX6369_WDSET (7 << 0)
43#define MAX6369_WDI (1 << 3)
44
45static DEFINE_SPINLOCK(io_lock);
46
47static unsigned long wdt_status;
48#define WDT_IN_USE 0
49#define WDT_RUNNING 1
50#define WDT_OK_TO_CLOSE 2
51
52static int nodelay;
53static struct resource *wdt_mem;
54static void __iomem *wdt_base;
55static struct platform_device *max63xx_pdev;
56
57/*
58 * The timeout values used are actually the absolute minimum the chip
59 * offers. Typical values on my board are slightly over twice as long
60 * (10s setting ends up with a 25s timeout), and can be up to 3 times
61 * the nominal setting (according to the datasheet). So please take
62 * these values with a grain of salt. Same goes for the initial delay
63 * "feature". Only max6373/74 have a few settings without this initial
64 * delay (selected with the "nodelay" parameter).
65 *
66 * I also decided to remove from the tables any timeout smaller than a
67 * second, as it looked completly overkill...
68 */
69
70/* Timeouts in second */
71struct max63xx_timeout {
72 u8 wdset;
73 u8 tdelay;
74 u8 twd;
75};
76
77static struct max63xx_timeout max6369_table[] = {
78 { 5, 1, 1 },
79 { 6, 10, 10 },
80 { 7, 60, 60 },
81 { },
82};
83
84static struct max63xx_timeout max6371_table[] = {
85 { 6, 60, 3 },
86 { 7, 60, 60 },
87 { },
88};
89
90static struct max63xx_timeout max6373_table[] = {
91 { 2, 60, 1 },
92 { 5, 0, 1 },
93 { 1, 3, 3 },
94 { 7, 60, 10 },
95 { 6, 0, 10 },
96 { },
97};
98
99static struct max63xx_timeout *current_timeout;
100
101static struct max63xx_timeout *
102max63xx_select_timeout(struct max63xx_timeout *table, int value)
103{
104 while (table->twd) {
105 if (value <= table->twd) {
106 if (nodelay && table->tdelay == 0)
107 return table;
108
109 if (!nodelay)
110 return table;
111 }
112
113 table++;
114 }
115
116 return NULL;
117}
118
119static void max63xx_wdt_ping(void)
120{
121 u8 val;
122
123 spin_lock(&io_lock);
124
125 val = __raw_readb(wdt_base);
126
127 __raw_writeb(val | MAX6369_WDI, wdt_base);
128 __raw_writeb(val & ~MAX6369_WDI, wdt_base);
129
130 spin_unlock(&io_lock);
131}
132
133static void max63xx_wdt_enable(struct max63xx_timeout *entry)
134{
135 u8 val;
136
137 if (test_and_set_bit(WDT_RUNNING, &wdt_status))
138 return;
139
140 spin_lock(&io_lock);
141
142 val = __raw_readb(wdt_base);
143 val &= ~MAX6369_WDSET;
144 val |= entry->wdset;
145 __raw_writeb(val, wdt_base);
146
147 spin_unlock(&io_lock);
148
149 /* check for a edge triggered startup */
150 if (entry->tdelay == 0)
151 max63xx_wdt_ping();
152}
153
154static void max63xx_wdt_disable(void)
155{
156 spin_lock(&io_lock);
157
158 __raw_writeb(3, wdt_base);
159
160 spin_unlock(&io_lock);
161
162 clear_bit(WDT_RUNNING, &wdt_status);
163}
164
165static int max63xx_wdt_open(struct inode *inode, struct file *file)
166{
167 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
168 return -EBUSY;
169
170 max63xx_wdt_enable(current_timeout);
171 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
172
173 return nonseekable_open(inode, file);
174}
175
176static ssize_t max63xx_wdt_write(struct file *file, const char *data,
177 size_t len, loff_t *ppos)
178{
179 if (len) {
180 if (!nowayout) {
181 size_t i;
182
183 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
184 for (i = 0; i != len; i++) {
185 char c;
186
187 if (get_user(c, data + i))
188 return -EFAULT;
189
190 if (c == 'V')
191 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
192 }
193 }
194
195 max63xx_wdt_ping();
196 }
197
198 return len;
199}
200
201static const struct watchdog_info ident = {
202 .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
203 .identity = "max63xx Watchdog",
204};
205
206static long max63xx_wdt_ioctl(struct file *file, unsigned int cmd,
207 unsigned long arg)
208{
209 int ret = -ENOTTY;
210
211 switch (cmd) {
212 case WDIOC_GETSUPPORT:
213 ret = copy_to_user((struct watchdog_info *)arg, &ident,
214 sizeof(ident)) ? -EFAULT : 0;
215 break;
216
217 case WDIOC_GETSTATUS:
218 case WDIOC_GETBOOTSTATUS:
219 ret = put_user(0, (int *)arg);
220 break;
221
222 case WDIOC_KEEPALIVE:
223 max63xx_wdt_ping();
224 ret = 0;
225 break;
226
227 case WDIOC_GETTIMEOUT:
228 ret = put_user(heartbeat, (int *)arg);
229 break;
230 }
231 return ret;
232}
233
234static int max63xx_wdt_release(struct inode *inode, struct file *file)
235{
236 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
237 max63xx_wdt_disable();
238 else
239 dev_crit(&max63xx_pdev->dev,
240 "device closed unexpectedly - timer will not stop\n");
241
242 clear_bit(WDT_IN_USE, &wdt_status);
243 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
244
245 return 0;
246}
247
248static const struct file_operations max63xx_wdt_fops = {
249 .owner = THIS_MODULE,
250 .llseek = no_llseek,
251 .write = max63xx_wdt_write,
252 .unlocked_ioctl = max63xx_wdt_ioctl,
253 .open = max63xx_wdt_open,
254 .release = max63xx_wdt_release,
255};
256
257static struct miscdevice max63xx_wdt_miscdev = {
258 .minor = WATCHDOG_MINOR,
259 .name = "watchdog",
260 .fops = &max63xx_wdt_fops,
261};
262
263static int __devinit max63xx_wdt_probe(struct platform_device *pdev)
264{
265 int ret = 0;
266 int size;
267 struct resource *res;
268 struct device *dev = &pdev->dev;
269 struct max63xx_timeout *table;
270
271 table = (struct max63xx_timeout *)pdev->id_entry->driver_data;
272
273 if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
274 heartbeat = DEFAULT_HEARTBEAT;
275
276 dev_info(dev, "requesting %ds heartbeat\n", heartbeat);
277 current_timeout = max63xx_select_timeout(table, heartbeat);
278
279 if (!current_timeout) {
280 dev_err(dev, "unable to satisfy heartbeat request\n");
281 return -EINVAL;
282 }
283
284 dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
285 current_timeout->twd, current_timeout->tdelay);
286
287 heartbeat = current_timeout->twd;
288
289 max63xx_pdev = pdev;
290
291 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
292 if (res == NULL) {
293 dev_err(dev, "failed to get memory region resource\n");
294 return -ENOENT;
295 }
296
297 size = resource_size(res);
298 wdt_mem = request_mem_region(res->start, size, pdev->name);
299
300 if (wdt_mem == NULL) {
301 dev_err(dev, "failed to get memory region\n");
302 return -ENOENT;
303 }
304
305 wdt_base = ioremap(res->start, size);
306 if (!wdt_base) {
307 dev_err(dev, "failed to map memory region\n");
308 ret = -ENOMEM;
309 goto out_request;
310 }
311
312 ret = misc_register(&max63xx_wdt_miscdev);
313 if (ret < 0) {
314 dev_err(dev, "cannot register misc device\n");
315 goto out_unmap;
316 }
317
318 return 0;
319
320out_unmap:
321 iounmap(wdt_base);
322out_request:
323 release_resource(wdt_mem);
324 kfree(wdt_mem);
325
326 return ret;
327}
328
329static int __devexit max63xx_wdt_remove(struct platform_device *pdev)
330{
331 misc_deregister(&max63xx_wdt_miscdev);
332 if (wdt_mem) {
333 release_resource(wdt_mem);
334 kfree(wdt_mem);
335 wdt_mem = NULL;
336 }
337
338 if (wdt_base)
339 iounmap(wdt_base);
340
341 return 0;
342}
343
344static struct platform_device_id max63xx_id_table[] = {
345 { "max6369_wdt", (kernel_ulong_t)max6369_table, },
346 { "max6370_wdt", (kernel_ulong_t)max6369_table, },
347 { "max6371_wdt", (kernel_ulong_t)max6371_table, },
348 { "max6372_wdt", (kernel_ulong_t)max6371_table, },
349 { "max6373_wdt", (kernel_ulong_t)max6373_table, },
350 { "max6374_wdt", (kernel_ulong_t)max6373_table, },
351 { },
352};
353MODULE_DEVICE_TABLE(platform, max63xx_id_table);
354
355static struct platform_driver max63xx_wdt_driver = {
356 .probe = max63xx_wdt_probe,
357 .remove = __devexit_p(max63xx_wdt_remove),
358 .id_table = max63xx_id_table,
359 .driver = {
360 .name = "max63xx_wdt",
361 .owner = THIS_MODULE,
362 },
363};
364
365static int __init max63xx_wdt_init(void)
366{
367 return platform_driver_register(&max63xx_wdt_driver);
368}
369
370static void __exit max63xx_wdt_exit(void)
371{
372 platform_driver_unregister(&max63xx_wdt_driver);
373}
374
375module_init(max63xx_wdt_init);
376module_exit(max63xx_wdt_exit);
377
378MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
379MODULE_DESCRIPTION("max63xx Watchdog Driver");
380
381module_param(heartbeat, int, 0);
382MODULE_PARM_DESC(heartbeat,
383 "Watchdog heartbeat period in seconds from 1 to "
384 __MODULE_STRING(MAX_HEARTBEAT) ", default "
385 __MODULE_STRING(DEFAULT_HEARTBEAT));
386
387module_param(nowayout, int, 0);
388MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
389 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
390
391module_param(nodelay, int, 0);
392MODULE_PARM_DESC(nodelay,
393 "Force selection of a timeout setting without initial delay "
394 "(max6373/74 only, default=0)");
395
396MODULE_LICENSE("GPL");
397MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);