2 * Watchdog driver for Atmel AT32AP700X devices
4 * Copyright (C) 2005-2006 Atmel Corporation
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/moduleparam.h>
15 #include <linux/miscdevice.h>
17 #include <linux/platform_device.h>
18 #include <linux/watchdog.h>
19 #include <linux/uaccess.h>
24 #define TIMEOUT_DEFAULT TIMEOUT_MAX
26 /* module parameters */
27 static int timeout = TIMEOUT_DEFAULT;
28 module_param(timeout, int, 0);
29 MODULE_PARM_DESC(timeout,
30 "Timeout value. Limited to be 1 or 2 seconds. (default="
31 __MODULE_STRING(TIMEOUT_DEFAULT) ")");
33 /* Watchdog registers and write/read macro */
36 #define WDT_CTRL_PSEL 8
37 #define WDT_CTRL_KEY 24
41 #define WDT_BIT(name) (1 << WDT_##name)
42 #define WDT_BF(name, value) ((value) << WDT_##name)
44 #define wdt_readl(dev, reg) \
45 __raw_readl((dev)->regs + WDT_##reg)
46 #define wdt_writel(dev, reg, value) \
47 __raw_writel((value), (dev)->regs + WDT_##reg)
49 struct wdt_at32ap700x {
53 struct miscdevice miscdev;
56 static struct wdt_at32ap700x *wdt;
59 * Disable the watchdog.
61 static inline void at32_wdt_stop(void)
63 unsigned long psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
64 wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
65 wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
69 * Enable and reset the watchdog.
71 static inline void at32_wdt_start(void)
73 /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
74 unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
76 wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
77 | WDT_BF(CTRL_PSEL, psel)
78 | WDT_BF(CTRL_KEY, 0x55));
79 wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
80 | WDT_BF(CTRL_PSEL, psel)
81 | WDT_BF(CTRL_KEY, 0xaa));
85 * Pat the watchdog timer.
87 static inline void at32_wdt_pat(void)
89 wdt_writel(wdt, CLR, 0x42);
93 * Watchdog device is opened, and watchdog starts running.
95 static int at32_wdt_open(struct inode *inode, struct file *file)
97 if (test_and_set_bit(1, &wdt->users))
101 return nonseekable_open(inode, file);
105 * Close the watchdog device. If CONFIG_WATCHDOG_NOWAYOUT is _not_ defined then
106 * the watchdog is also disabled.
108 static int at32_wdt_close(struct inode *inode, struct file *file)
110 #ifndef CONFIG_WATCHDOG_NOWAYOUT
113 clear_bit(1, &wdt->users);
118 * Change the watchdog time interval.
120 static int at32_wdt_settimeout(int time)
123 * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
124 * 2 ^ 16 allowing up to 2 seconds timeout.
126 if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
130 * Set new watchdog time. It will be used when at32_wdt_start() is
137 static struct watchdog_info at32_wdt_info = {
138 .identity = "at32ap700x watchdog",
139 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
143 * Handle commands from user-space.
145 static int at32_wdt_ioctl(struct inode *inode, struct file *file,
146 unsigned int cmd, unsigned long arg)
150 void __user *argp = (void __user *)arg;
151 int __user *p = argp;
154 case WDIOC_KEEPALIVE:
158 case WDIOC_GETSUPPORT:
159 ret = copy_to_user(argp, &at32_wdt_info,
160 sizeof(at32_wdt_info)) ? -EFAULT : 0;
162 case WDIOC_SETTIMEOUT:
163 ret = get_user(time, p);
166 ret = at32_wdt_settimeout(time);
169 /* Enable new time value */
172 case WDIOC_GETTIMEOUT:
173 ret = put_user(wdt->timeout, p);
175 case WDIOC_GETSTATUS: /* fall through */
176 case WDIOC_GETBOOTSTATUS:
177 ret = put_user(0, p);
179 case WDIOC_SETOPTIONS:
180 ret = get_user(time, p);
183 if (time & WDIOS_DISABLECARD)
185 if (time & WDIOS_ENABLECARD)
194 static ssize_t at32_wdt_write(struct file *file, const char *data, size_t len,
201 static const struct file_operations at32_wdt_fops = {
202 .owner = THIS_MODULE,
204 .ioctl = at32_wdt_ioctl,
205 .open = at32_wdt_open,
206 .release = at32_wdt_close,
207 .write = at32_wdt_write,
210 static int __init at32_wdt_probe(struct platform_device *pdev)
212 struct resource *regs;
216 dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
220 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
222 dev_dbg(&pdev->dev, "missing mmio resource\n");
226 wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL);
228 dev_dbg(&pdev->dev, "no memory for wdt structure\n");
232 wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
235 dev_dbg(&pdev->dev, "could not map I/O memory\n");
239 wdt->miscdev.minor = WATCHDOG_MINOR;
240 wdt->miscdev.name = "watchdog";
241 wdt->miscdev.fops = &at32_wdt_fops;
243 if (at32_wdt_settimeout(timeout)) {
244 at32_wdt_settimeout(TIMEOUT_DEFAULT);
246 "default timeout invalid, set to %d sec.\n",
250 ret = misc_register(&wdt->miscdev);
252 dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
256 platform_set_drvdata(pdev, wdt);
257 wdt->miscdev.parent = &pdev->dev;
258 dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p, timeout %d sec\n",
259 wdt->regs, wdt->timeout);
271 static int __exit at32_wdt_remove(struct platform_device *pdev)
273 if (wdt && platform_get_drvdata(pdev) == wdt) {
274 misc_deregister(&wdt->miscdev);
278 platform_set_drvdata(pdev, NULL);
284 static void at32_wdt_shutdown(struct platform_device *pdev)
290 static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
296 static int at32_wdt_resume(struct platform_device *pdev)
303 #define at32_wdt_suspend NULL
304 #define at32_wdt_resume NULL
307 static struct platform_driver at32_wdt_driver = {
308 .remove = __exit_p(at32_wdt_remove),
309 .suspend = at32_wdt_suspend,
310 .resume = at32_wdt_resume,
313 .owner = THIS_MODULE,
315 .shutdown = at32_wdt_shutdown,
318 static int __init at32_wdt_init(void)
320 return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe);
322 module_init(at32_wdt_init);
324 static void __exit at32_wdt_exit(void)
326 platform_driver_unregister(&at32_wdt_driver);
328 module_exit(at32_wdt_exit);
330 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
331 MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
332 MODULE_LICENSE("GPL");
333 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);