1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * National Semiconductor PC87307/PC97307 (ala SC1200) WDT driver
4 * (c) Copyright 2002 Zwane Mwaikambo <zwane@commfireservices.com>,
6 * Based on wdt.c and wdt977.c by Alan Cox and Woody Suwalski respectively.
8 * The author(s) of this software shall not be held liable for damages
9 * of any nature resulting due to the use of this software. This
10 * software is provided AS-IS with no warranties.
13 * 20020220 Zwane Mwaikambo Code based on datasheet, no hardware.
14 * 20020221 Zwane Mwaikambo Cleanups as suggested by Jeff Garzik
16 * 20020222 Zwane Mwaikambo Added probing.
17 * 20020225 Zwane Mwaikambo Added ISAPNP support.
18 * 20020412 Rob Radez Broke out start/stop functions
19 * <rob@osinvestor.com> Return proper status instead of
21 * Add WDIOC_GETBOOTSTATUS and
22 * WDIOC_SETOPTIONS ioctls
23 * Fix CONFIG_WATCHDOG_NOWAYOUT
24 * 20020530 Joel Becker Add Matt Domsch's nowayout module
26 * 20030116 Adam Belay Updated to the latest pnp code
29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/miscdevice.h>
34 #include <linux/watchdog.h>
35 #include <linux/ioport.h>
36 #include <linux/spinlock.h>
37 #include <linux/notifier.h>
38 #include <linux/reboot.h>
39 #include <linux/init.h>
40 #include <linux/pnp.h>
42 #include <linux/semaphore.h>
44 #include <linux/uaccess.h>
46 #define SC1200_MODULE_VER "build 20020303"
47 #define SC1200_MODULE_NAME "sc1200wdt"
49 #define MAX_TIMEOUT 255 /* 255 minutes */
50 #define PMIR (io) /* Power Management Index Register */
51 #define PMDR (io+1) /* Power Management Data Register */
53 /* Data Register indexes */
54 #define FER1 0x00 /* Function enable register 1 */
55 #define FER2 0x01 /* Function enable register 2 */
56 #define PMC1 0x02 /* Power Management Ctrl 1 */
57 #define PMC2 0x03 /* Power Management Ctrl 2 */
58 #define PMC3 0x04 /* Power Management Ctrl 3 */
59 #define WDTO 0x05 /* Watchdog timeout register */
60 #define WDCF 0x06 /* Watchdog config register */
61 #define WDST 0x07 /* Watchdog status register */
63 /* WDCF bitfields - which devices assert WDO */
64 #define KBC_IRQ 0x01 /* Keyboard Controller */
65 #define MSE_IRQ 0x02 /* Mouse */
66 #define UART1_IRQ 0x03 /* Serial0 */
67 #define UART2_IRQ 0x04 /* Serial1 */
68 /* 5 -7 are reserved */
70 static int timeout = 1;
72 static int io_len = 2; /* for non plug and play */
73 static unsigned long open_flag;
74 static char expect_close;
75 static DEFINE_SPINLOCK(sc1200wdt_lock); /* io port access serialisation */
77 #if defined CONFIG_PNP
78 static int isapnp = 1;
79 static struct pnp_dev *wdt_dev;
81 module_param(isapnp, int, 0);
82 MODULE_PARM_DESC(isapnp,
83 "When set to 0 driver ISA PnP support will be disabled");
86 module_param_hw(io, int, ioport, 0);
87 MODULE_PARM_DESC(io, "io port");
88 module_param(timeout, int, 0);
89 MODULE_PARM_DESC(timeout, "range is 0-255 minutes, default is 1");
91 static bool nowayout = WATCHDOG_NOWAYOUT;
92 module_param(nowayout, bool, 0);
93 MODULE_PARM_DESC(nowayout,
94 "Watchdog cannot be stopped once started (default="
95 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
99 /* Read from Data Register */
100 static inline void __sc1200wdt_read_data(unsigned char index,
107 static void sc1200wdt_read_data(unsigned char index, unsigned char *data)
109 spin_lock(&sc1200wdt_lock);
110 __sc1200wdt_read_data(index, data);
111 spin_unlock(&sc1200wdt_lock);
114 /* Write to Data Register */
115 static inline void __sc1200wdt_write_data(unsigned char index,
122 static inline void sc1200wdt_write_data(unsigned char index,
125 spin_lock(&sc1200wdt_lock);
126 __sc1200wdt_write_data(index, data);
127 spin_unlock(&sc1200wdt_lock);
131 static void sc1200wdt_start(void)
134 spin_lock(&sc1200wdt_lock);
136 __sc1200wdt_read_data(WDCF, ®);
137 /* assert WDO when any of the following interrupts are triggered too */
138 reg |= (KBC_IRQ | MSE_IRQ | UART1_IRQ | UART2_IRQ);
139 __sc1200wdt_write_data(WDCF, reg);
140 /* set the timeout and get the ball rolling */
141 __sc1200wdt_write_data(WDTO, timeout);
143 spin_unlock(&sc1200wdt_lock);
146 static void sc1200wdt_stop(void)
148 sc1200wdt_write_data(WDTO, 0);
151 /* This returns the status of the WDO signal, inactive high. */
152 static inline int sc1200wdt_status(void)
156 sc1200wdt_read_data(WDST, &ret);
157 /* If the bit is inactive, the watchdog is enabled, so return
158 * KEEPALIVEPING which is a bit of a kludge because there's nothing
159 * else for enabled/disabled status
161 return (ret & 0x01) ? 0 : WDIOF_KEEPALIVEPING;
164 static int sc1200wdt_open(struct inode *inode, struct file *file)
166 /* allow one at a time */
167 if (test_and_set_bit(0, &open_flag))
170 if (timeout > MAX_TIMEOUT)
171 timeout = MAX_TIMEOUT;
174 pr_info("Watchdog enabled, timeout = %d min(s)", timeout);
176 return stream_open(inode, file);
180 static long sc1200wdt_ioctl(struct file *file, unsigned int cmd,
184 void __user *argp = (void __user *)arg;
185 int __user *p = argp;
186 static const struct watchdog_info ident = {
187 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
189 .firmware_version = 0,
190 .identity = "PC87307/PC97307",
194 case WDIOC_GETSUPPORT:
195 if (copy_to_user(argp, &ident, sizeof(ident)))
199 case WDIOC_GETSTATUS:
200 return put_user(sc1200wdt_status(), p);
202 case WDIOC_GETBOOTSTATUS:
203 return put_user(0, p);
205 case WDIOC_SETOPTIONS:
207 int options, retval = -EINVAL;
209 if (get_user(options, p))
212 if (options & WDIOS_DISABLECARD) {
217 if (options & WDIOS_ENABLECARD) {
224 case WDIOC_KEEPALIVE:
225 sc1200wdt_write_data(WDTO, timeout);
228 case WDIOC_SETTIMEOUT:
229 if (get_user(new_timeout, p))
231 /* the API states this is given in secs */
233 if (new_timeout < 0 || new_timeout > MAX_TIMEOUT)
235 timeout = new_timeout;
236 sc1200wdt_write_data(WDTO, timeout);
237 fallthrough; /* and return the new timeout */
239 case WDIOC_GETTIMEOUT:
240 return put_user(timeout * 60, p);
248 static int sc1200wdt_release(struct inode *inode, struct file *file)
250 if (expect_close == 42) {
252 pr_info("Watchdog disabled\n");
254 sc1200wdt_write_data(WDTO, timeout);
255 pr_crit("Unexpected close!, timeout = %d min(s)\n", timeout);
257 clear_bit(0, &open_flag);
264 static ssize_t sc1200wdt_write(struct file *file, const char __user *data,
265 size_t len, loff_t *ppos)
273 for (i = 0; i != len; i++) {
276 if (get_user(c, data + i))
283 sc1200wdt_write_data(WDTO, timeout);
291 static int sc1200wdt_notify_sys(struct notifier_block *this,
292 unsigned long code, void *unused)
294 if (code == SYS_DOWN || code == SYS_HALT)
301 static struct notifier_block sc1200wdt_notifier = {
302 .notifier_call = sc1200wdt_notify_sys,
305 static const struct file_operations sc1200wdt_fops = {
306 .owner = THIS_MODULE,
308 .write = sc1200wdt_write,
309 .unlocked_ioctl = sc1200wdt_ioctl,
310 .compat_ioctl = compat_ptr_ioctl,
311 .open = sc1200wdt_open,
312 .release = sc1200wdt_release,
315 static struct miscdevice sc1200wdt_miscdev = {
316 .minor = WATCHDOG_MINOR,
318 .fops = &sc1200wdt_fops,
322 static int __init sc1200wdt_probe(void)
324 /* The probe works by reading the PMC3 register's default value of 0x0e
325 * there is one caveat, if the device disables the parallel port or any
326 * of the UARTs we won't be able to detect it.
327 * NB. This could be done with accuracy by reading the SID registers,
328 * but we don't have access to those io regions.
333 sc1200wdt_read_data(PMC3, ®);
334 reg &= 0x0f; /* we don't want the UART busy bits */
335 return (reg == 0x0e) ? 0 : -ENODEV;
339 #if defined CONFIG_PNP
341 static const struct pnp_device_id scl200wdt_pnp_devices[] = {
342 /* National Semiconductor PC87307/PC97307 watchdog component */
343 {.id = "NSC0800", .driver_data = 0},
347 static int scl200wdt_pnp_probe(struct pnp_dev *dev,
348 const struct pnp_device_id *dev_id)
350 /* this driver only supports one card at a time */
351 if (wdt_dev || !isapnp)
355 io = pnp_port_start(wdt_dev, 0);
356 io_len = pnp_port_len(wdt_dev, 0);
358 if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
359 pr_err("Unable to register IO port %#x\n", io);
363 pr_info("PnP device found at io port %#x/%d\n", io, io_len);
367 static void scl200wdt_pnp_remove(struct pnp_dev *dev)
370 release_region(io, io_len);
375 static struct pnp_driver scl200wdt_pnp_driver = {
377 .id_table = scl200wdt_pnp_devices,
378 .probe = scl200wdt_pnp_probe,
379 .remove = scl200wdt_pnp_remove,
382 #endif /* CONFIG_PNP */
385 static int __init sc1200wdt_init(void)
389 pr_info("%s\n", SC1200_MODULE_VER);
391 #if defined CONFIG_PNP
393 ret = pnp_register_driver(&scl200wdt_pnp_driver);
400 pr_err("io parameter must be specified\n");
405 #if defined CONFIG_PNP
406 /* now that the user has specified an IO port and we haven't detected
407 * any devices, disable pnp support */
409 pnp_unregister_driver(&scl200wdt_pnp_driver);
413 if (!request_region(io, io_len, SC1200_MODULE_NAME)) {
414 pr_err("Unable to register IO port %#x\n", io);
419 ret = sc1200wdt_probe();
423 ret = register_reboot_notifier(&sc1200wdt_notifier);
425 pr_err("Unable to register reboot notifier err = %d\n", ret);
429 ret = misc_register(&sc1200wdt_miscdev);
431 pr_err("Unable to register miscdev on minor %d\n",
442 unregister_reboot_notifier(&sc1200wdt_notifier);
445 release_region(io, io_len);
448 #if defined CONFIG_PNP
450 pnp_unregister_driver(&scl200wdt_pnp_driver);
456 static void __exit sc1200wdt_exit(void)
458 misc_deregister(&sc1200wdt_miscdev);
459 unregister_reboot_notifier(&sc1200wdt_notifier);
461 #if defined CONFIG_PNP
463 pnp_unregister_driver(&scl200wdt_pnp_driver);
466 release_region(io, io_len);
469 module_init(sc1200wdt_init);
470 module_exit(sc1200wdt_exit);
472 MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
474 "Driver for National Semiconductor PC87307/PC97307 watchdog component");
475 MODULE_LICENSE("GPL");