1 #include <linux/init.h>
2 #include <linux/module.h>
3 #include <linux/miscdevice.h>
4 #include <linux/watchdog.h>
6 #include <linux/spinlock.h>
7 #include <linux/of_platform.h>
8 #include <linux/uaccess.h>
9 #include <asm/mpc52xx.h>
12 #define GPT_MODE_WDT (1 << 15)
13 #define GPT_MODE_CE (1 << 12)
14 #define GPT_MODE_MS_TIMER (0x4)
18 unsigned count; /* timer ticks before watchdog kicks in */
20 struct miscdevice miscdev;
22 struct mpc52xx_gpt __iomem *regs;
26 /* is_active stores wether or not the /dev/watchdog device is opened */
27 static unsigned long is_active;
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...
32 static struct mpc5200_wdt *wdt_global;
35 /* helper to calculate timeout in timer counts */
36 static void mpc5200_wdt_set_timeout(struct mpc5200_wdt *wdt, int timeout)
38 /* use biggest prescaler of 64k */
39 wdt->count = (wdt->ipb_freq + 0xffff) / 0x10000 * timeout;
41 if (wdt->count > 0xffff)
44 /* return timeout in seconds (calculated from timer count) */
45 static int mpc5200_wdt_get_timeout(struct mpc5200_wdt *wdt)
47 return wdt->count * 0x10000 / wdt->ipb_freq;
51 /* watchdog operations */
52 static int mpc5200_wdt_start(struct mpc5200_wdt *wdt)
54 spin_lock(&wdt->io_lock);
56 out_be32(&wdt->regs->mode, 0);
57 /* set timeout, with maximum prescaler */
58 out_be32(&wdt->regs->count, 0x0 | wdt->count);
60 out_be32(&wdt->regs->mode, GPT_MODE_CE | GPT_MODE_WDT |
62 spin_unlock(&wdt->io_lock);
66 static int mpc5200_wdt_ping(struct mpc5200_wdt *wdt)
68 spin_lock(&wdt->io_lock);
69 /* writing A5 to OCPW resets the watchdog */
70 out_be32(&wdt->regs->mode, 0xA5000000 |
71 (0xffffff & in_be32(&wdt->regs->mode)));
72 spin_unlock(&wdt->io_lock);
75 static int mpc5200_wdt_stop(struct mpc5200_wdt *wdt)
77 spin_lock(&wdt->io_lock);
79 out_be32(&wdt->regs->mode, 0);
80 spin_unlock(&wdt->io_lock);
86 static ssize_t mpc5200_wdt_write(struct file *file, const char __user *data,
87 size_t len, loff_t *ppos)
89 struct mpc5200_wdt *wdt = file->private_data;
90 mpc5200_wdt_ping(wdt);
93 static struct watchdog_info mpc5200_wdt_info = {
94 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
95 .identity = "mpc5200 watchdog on GPT0",
97 static long mpc5200_wdt_ioctl(struct file *file, unsigned int cmd,
100 struct mpc5200_wdt *wdt = file->private_data;
101 int __user *data = (int __user *)arg;
106 case WDIOC_GETSUPPORT:
107 ret = copy_to_user(data, &mpc5200_wdt_info,
108 sizeof(mpc5200_wdt_info));
113 case WDIOC_GETSTATUS:
114 case WDIOC_GETBOOTSTATUS:
115 ret = put_user(0, data);
118 case WDIOC_KEEPALIVE:
119 mpc5200_wdt_ping(wdt);
122 case WDIOC_SETTIMEOUT:
123 ret = get_user(timeout, data);
126 mpc5200_wdt_set_timeout(wdt, timeout);
127 mpc5200_wdt_start(wdt);
128 /* fall through and return the timeout */
130 case WDIOC_GETTIMEOUT:
131 timeout = mpc5200_wdt_get_timeout(wdt);
132 ret = put_user(timeout, data);
141 static int mpc5200_wdt_open(struct inode *inode, struct file *file)
143 /* /dev/watchdog can only be opened once */
144 if (test_and_set_bit(0, &is_active))
147 /* Set and activate the watchdog */
148 mpc5200_wdt_set_timeout(wdt_global, 30);
149 mpc5200_wdt_start(wdt_global);
150 file->private_data = wdt_global;
151 return nonseekable_open(inode, file);
153 static int mpc5200_wdt_release(struct inode *inode, struct file *file)
155 #if WATCHDOG_NOWAYOUT == 0
156 struct mpc5200_wdt *wdt = file->private_data;
157 mpc5200_wdt_stop(wdt);
158 wdt->count = 0; /* == disabled */
160 clear_bit(0, &is_active);
164 static const struct file_operations mpc5200_wdt_fops = {
165 .owner = THIS_MODULE,
166 .write = mpc5200_wdt_write,
167 .unlocked_ioctl = mpc5200_wdt_ioctl,
168 .open = mpc5200_wdt_open,
169 .release = mpc5200_wdt_release,
172 /* module operations */
173 static int mpc5200_wdt_probe(struct of_device *op,
174 const struct of_device_id *match)
176 struct mpc5200_wdt *wdt;
181 has_wdt = of_get_property(op->node, "has-wdt", NULL);
183 has_wdt = of_get_property(op->node, "fsl,has-wdt", NULL);
187 wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
191 wdt->ipb_freq = mpc5xxx_get_bus_frequency(op->node);
193 err = of_address_to_resource(op->node, 0, &wdt->mem);
196 size = wdt->mem.end - wdt->mem.start + 1;
197 if (!request_mem_region(wdt->mem.start, size, "mpc5200_wdt")) {
201 wdt->regs = ioremap(wdt->mem.start, size);
207 dev_set_drvdata(&op->dev, wdt);
208 spin_lock_init(&wdt->io_lock);
210 wdt->miscdev = (struct miscdevice) {
211 .minor = WATCHDOG_MINOR,
213 .fops = &mpc5200_wdt_fops,
217 err = misc_register(&wdt->miscdev);
223 release_mem_region(wdt->mem.start, size);
229 static int mpc5200_wdt_remove(struct of_device *op)
231 struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
233 mpc5200_wdt_stop(wdt);
234 misc_deregister(&wdt->miscdev);
236 release_mem_region(wdt->mem.start, wdt->mem.end - wdt->mem.start + 1);
241 static int mpc5200_wdt_suspend(struct of_device *op, pm_message_t state)
243 struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
244 mpc5200_wdt_stop(wdt);
247 static int mpc5200_wdt_resume(struct of_device *op)
249 struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
251 mpc5200_wdt_start(wdt);
254 static int mpc5200_wdt_shutdown(struct of_device *op)
256 struct mpc5200_wdt *wdt = dev_get_drvdata(&op->dev);
257 mpc5200_wdt_stop(wdt);
261 static struct of_device_id mpc5200_wdt_match[] = {
262 { .compatible = "mpc5200-gpt", },
263 { .compatible = "fsl,mpc5200-gpt", },
266 static 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,
278 static int __init mpc5200_wdt_init(void)
280 return of_register_platform_driver(&mpc5200_wdt_driver);
283 static void __exit mpc5200_wdt_exit(void)
285 of_unregister_platform_driver(&mpc5200_wdt_driver);
288 module_init(mpc5200_wdt_init);
289 module_exit(mpc5200_wdt_exit);
291 MODULE_AUTHOR("Domen Puncer <domen.puncer@telargo.com>");
292 MODULE_LICENSE("Dual BSD/GPL");
293 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);