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Domen Puncer8cf18972007-06-18 08:17:57 +02001#include <linux/init.h>
2#include <linux/module.h>
3#include <linux/miscdevice.h>
4#include <linux/watchdog.h>
5#include <linux/io.h>
Wim Van Sebroeckde812252007-07-20 21:22:58 +00006#include <linux/spinlock.h>
Alan Coxf26ef3d2008-05-19 14:07:09 +01007#include <linux/of_platform.h>
8#include <linux/uaccess.h>
Domen Puncer8cf18972007-06-18 08:17:57 +02009#include <asm/mpc52xx.h>
10
11
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +000012#define GPT_MODE_WDT (1 << 15)
13#define GPT_MODE_CE (1 << 12)
Domen Puncer8cf18972007-06-18 08:17:57 +020014#define GPT_MODE_MS_TIMER (0x4)
15
16
17struct mpc5200_wdt {
18 unsigned count; /* timer ticks before watchdog kicks in */
19 long ipb_freq;
20 struct miscdevice miscdev;
21 struct resource mem;
22 struct mpc52xx_gpt __iomem *regs;
Wim Van Sebroeckde812252007-07-20 21:22:58 +000023 spinlock_t io_lock;
Domen Puncer8cf18972007-06-18 08:17:57 +020024};
25
Wim Van Sebroeckde812252007-07-20 21:22:58 +000026/* is_active stores wether or not the /dev/watchdog device is opened */
27static unsigned long is_active;
Domen Puncer8cf18972007-06-18 08:17:57 +020028
29/* misc devices don't provide a way, to get back to 'dev' or 'miscdev' from
30 * file operations, which sucks. But there can be max 1 watchdog anyway, so...
31 */
32static struct mpc5200_wdt *wdt_global;
33
34
35/* helper to calculate timeout in timer counts */
36static void mpc5200_wdt_set_timeout(struct mpc5200_wdt *wdt, int timeout)
37{
38 /* use biggest prescaler of 64k */
39 wdt->count = (wdt->ipb_freq + 0xffff) / 0x10000 * timeout;
40
41 if (wdt->count > 0xffff)
42 wdt->count = 0xffff;
43}
44/* return timeout in seconds (calculated from timer count) */
45static int mpc5200_wdt_get_timeout(struct mpc5200_wdt *wdt)
46{
47 return wdt->count * 0x10000 / wdt->ipb_freq;
48}
49
50
51/* watchdog operations */
52static int mpc5200_wdt_start(struct mpc5200_wdt *wdt)
53{
Wim Van Sebroeckde812252007-07-20 21:22:58 +000054 spin_lock(&wdt->io_lock);
Domen Puncer8cf18972007-06-18 08:17:57 +020055 /* disable */
56 out_be32(&wdt->regs->mode, 0);
57 /* set timeout, with maximum prescaler */
58 out_be32(&wdt->regs->count, 0x0 | wdt->count);
59 /* enable watchdog */
Alan Coxf26ef3d2008-05-19 14:07:09 +010060 out_be32(&wdt->regs->mode, GPT_MODE_CE | GPT_MODE_WDT |
61 GPT_MODE_MS_TIMER);
Wim Van Sebroeckde812252007-07-20 21:22:58 +000062 spin_unlock(&wdt->io_lock);
Domen Puncer8cf18972007-06-18 08:17:57 +020063
64 return 0;
65}
66static int mpc5200_wdt_ping(struct mpc5200_wdt *wdt)
67{
Wim Van Sebroeckde812252007-07-20 21:22:58 +000068 spin_lock(&wdt->io_lock);
Domen Puncer8cf18972007-06-18 08:17:57 +020069 /* writing A5 to OCPW resets the watchdog */
Alan Coxf26ef3d2008-05-19 14:07:09 +010070 out_be32(&wdt->regs->mode, 0xA5000000 |
71 (0xffffff & in_be32(&wdt->regs->mode)));
Wim Van Sebroeckde812252007-07-20 21:22:58 +000072 spin_unlock(&wdt->io_lock);
Domen Puncer8cf18972007-06-18 08:17:57 +020073 return 0;
74}
75static int mpc5200_wdt_stop(struct mpc5200_wdt *wdt)
76{
Wim Van Sebroeckde812252007-07-20 21:22:58 +000077 spin_lock(&wdt->io_lock);
78 /* disable */
Domen Puncer8cf18972007-06-18 08:17:57 +020079 out_be32(&wdt->regs->mode, 0);
Wim Van Sebroeckde812252007-07-20 21:22:58 +000080 spin_unlock(&wdt->io_lock);
Domen Puncer8cf18972007-06-18 08:17:57 +020081 return 0;
82}
83
84
85/* file operations */
Al Viroa39f9d02007-10-14 19:34:20 +010086static ssize_t mpc5200_wdt_write(struct file *file, const char __user *data,
Domen Puncer8cf18972007-06-18 08:17:57 +020087 size_t len, loff_t *ppos)
88{
89 struct mpc5200_wdt *wdt = file->private_data;
90 mpc5200_wdt_ping(wdt);
91 return 0;
92}
93static struct watchdog_info mpc5200_wdt_info = {
94 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
95 .identity = "mpc5200 watchdog on GPT0",
96};
Alan Coxf26ef3d2008-05-19 14:07:09 +010097static long mpc5200_wdt_ioctl(struct file *file, unsigned int cmd,
98 unsigned long arg)
Domen Puncer8cf18972007-06-18 08:17:57 +020099{
100 struct mpc5200_wdt *wdt = file->private_data;
101 int __user *data = (int __user *)arg;
102 int timeout;
103 int ret = 0;
104
105 switch (cmd) {
106 case WDIOC_GETSUPPORT:
Wim Van Sebroeckde812252007-07-20 21:22:58 +0000107 ret = copy_to_user(data, &mpc5200_wdt_info,
Alan Coxf26ef3d2008-05-19 14:07:09 +0100108 sizeof(mpc5200_wdt_info));
Domen Puncer8cf18972007-06-18 08:17:57 +0200109 if (ret)
110 ret = -EFAULT;
111 break;
112
Wim Van Sebroeckde812252007-07-20 21:22:58 +0000113 case WDIOC_GETSTATUS:
114 case WDIOC_GETBOOTSTATUS:
115 ret = put_user(0, data);
116 break;
117
Domen Puncer8cf18972007-06-18 08:17:57 +0200118 case WDIOC_KEEPALIVE:
119 mpc5200_wdt_ping(wdt);
120 break;
121
122 case WDIOC_SETTIMEOUT:
123 ret = get_user(timeout, data);
124 if (ret)
125 break;
126 mpc5200_wdt_set_timeout(wdt, timeout);
127 mpc5200_wdt_start(wdt);
128 /* fall through and return the timeout */
129
130 case WDIOC_GETTIMEOUT:
131 timeout = mpc5200_wdt_get_timeout(wdt);
132 ret = put_user(timeout, data);
133 break;
Wim Van Sebroeckde812252007-07-20 21:22:58 +0000134
135 default:
136 ret = -ENOTTY;
Domen Puncer8cf18972007-06-18 08:17:57 +0200137 }
138 return ret;
139}
Alan Coxf26ef3d2008-05-19 14:07:09 +0100140
Domen Puncer8cf18972007-06-18 08:17:57 +0200141static int mpc5200_wdt_open(struct inode *inode, struct file *file)
142{
Wim Van Sebroeckde812252007-07-20 21:22:58 +0000143 /* /dev/watchdog can only be opened once */
144 if (test_and_set_bit(0, &is_active))
145 return -EBUSY;
146
147 /* Set and activate the watchdog */
Domen Puncer8cf18972007-06-18 08:17:57 +0200148 mpc5200_wdt_set_timeout(wdt_global, 30);
149 mpc5200_wdt_start(wdt_global);
150 file->private_data = wdt_global;
Wim Van Sebroeckde812252007-07-20 21:22:58 +0000151 return nonseekable_open(inode, file);
Domen Puncer8cf18972007-06-18 08:17:57 +0200152}
153static int mpc5200_wdt_release(struct inode *inode, struct file *file)
154{
155#if WATCHDOG_NOWAYOUT == 0
156 struct mpc5200_wdt *wdt = file->private_data;
157 mpc5200_wdt_stop(wdt);
158 wdt->count = 0; /* == disabled */
159#endif
Wim Van Sebroeckde812252007-07-20 21:22:58 +0000160 clear_bit(0, &is_active);
Domen Puncer8cf18972007-06-18 08:17:57 +0200161 return 0;
162}
163
Jan Engelhardtb47a1662008-01-22 20:48:10 +0100164static const struct file_operations mpc5200_wdt_fops = {
Domen Puncer8cf18972007-06-18 08:17:57 +0200165 .owner = THIS_MODULE,
166 .write = mpc5200_wdt_write,
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000167 .unlocked_ioctl = mpc5200_wdt_ioctl,
Domen Puncer8cf18972007-06-18 08:17:57 +0200168 .open = mpc5200_wdt_open,
169 .release = mpc5200_wdt_release,
170};
171
172/* module operations */
Alan Coxf26ef3d2008-05-19 14:07:09 +0100173static int mpc5200_wdt_probe(struct of_device *op,
174 const struct of_device_id *match)
Domen Puncer8cf18972007-06-18 08:17:57 +0200175{
176 struct mpc5200_wdt *wdt;
177 int err;
178 const void *has_wdt;
179 int size;
180
181 has_wdt = of_get_property(op->node, "has-wdt", NULL);
182 if (!has_wdt)
Marian Balakowiczd24bc312007-10-19 04:44:24 +1000183 has_wdt = of_get_property(op->node, "fsl,has-wdt", NULL);
184 if (!has_wdt)
Domen Puncer8cf18972007-06-18 08:17:57 +0200185 return -ENODEV;
186
187 wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
188 if (!wdt)
189 return -ENOMEM;
190
Wolfgang Denk87c441e2009-06-17 00:30:22 -0600191 wdt->ipb_freq = mpc5xxx_get_bus_frequency(op->node);
Domen Puncer8cf18972007-06-18 08:17:57 +0200192
193 err = of_address_to_resource(op->node, 0, &wdt->mem);
194 if (err)
195 goto out_free;
196 size = wdt->mem.end - wdt->mem.start + 1;
197 if (!request_mem_region(wdt->mem.start, size, "mpc5200_wdt")) {
198 err = -ENODEV;
199 goto out_free;
200 }
201 wdt->regs = ioremap(wdt->mem.start, size);
202 if (!wdt->regs) {
203 err = -ENODEV;
204 goto out_release;
205 }
206
207 dev_set_drvdata(&op->dev, wdt);
Wim Van Sebroeckde812252007-07-20 21:22:58 +0000208 spin_lock_init(&wdt->io_lock);
Domen Puncer8cf18972007-06-18 08:17:57 +0200209
210 wdt->miscdev = (struct miscdevice) {
211 .minor = WATCHDOG_MINOR,
212 .name = "watchdog",
213 .fops = &mpc5200_wdt_fops,
214 .parent = &op->dev,
215 };
216 wdt_global = wdt;
217 err = misc_register(&wdt->miscdev);
218 if (!err)
219 return 0;
220
221 iounmap(wdt->regs);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000222out_release:
Domen Puncer8cf18972007-06-18 08:17:57 +0200223 release_mem_region(wdt->mem.start, size);
Wim Van Sebroeck7944d3a2008-08-06 20:19:41 +0000224out_free:
Domen Puncer8cf18972007-06-18 08:17:57 +0200225 kfree(wdt);
226 return err;
227}
228
229static int mpc5200_wdt_remove(struct of_device *op)
230{
231 struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
232
233 mpc5200_wdt_stop(wdt);
234 misc_deregister(&wdt->miscdev);
235 iounmap(wdt->regs);
236 release_mem_region(wdt->mem.start, wdt->mem.end - wdt->mem.start + 1);
237 kfree(wdt);
238
239 return 0;
240}
241static int mpc5200_wdt_suspend(struct of_device *op, pm_message_t state)
242{
243 struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
244 mpc5200_wdt_stop(wdt);
245 return 0;
246}
247static int mpc5200_wdt_resume(struct of_device *op)
248{
249 struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
250 if (wdt->count)
251 mpc5200_wdt_start(wdt);
252 return 0;
253}
254static int mpc5200_wdt_shutdown(struct of_device *op)
255{
256 struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
257 mpc5200_wdt_stop(wdt);
258 return 0;
259}
260
261static struct of_device_id mpc5200_wdt_match[] = {
262 { .compatible = "mpc5200-gpt", },
Marian Balakowiczd24bc312007-10-19 04:44:24 +1000263 { .compatible = "fsl,mpc5200-gpt", },
Domen Puncer8cf18972007-06-18 08:17:57 +0200264 {},
265};
266static struct of_platform_driver mpc5200_wdt_driver = {
267 .owner = THIS_MODULE,
268 .name = "mpc5200-gpt-wdt",
269 .match_table = mpc5200_wdt_match,
270 .probe = mpc5200_wdt_probe,
271 .remove = mpc5200_wdt_remove,
272 .suspend = mpc5200_wdt_suspend,
273 .resume = mpc5200_wdt_resume,
274 .shutdown = mpc5200_wdt_shutdown,
275};
276
277
278static int __init mpc5200_wdt_init(void)
279{
280 return of_register_platform_driver(&mpc5200_wdt_driver);
281}
282
283static void __exit mpc5200_wdt_exit(void)
284{
285 of_unregister_platform_driver(&mpc5200_wdt_driver);
286}
287
288module_init(mpc5200_wdt_init);
289module_exit(mpc5200_wdt_exit);
290
291MODULE_AUTHOR("Domen Puncer <domen.puncer@telargo.com>");
292MODULE_LICENSE("Dual BSD/GPL");
Wim Van Sebroeckde812252007-07-20 21:22:58 +0000293MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);