2 * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
4 * Authors: Dave Updegraff <dave@cray.org>
5 * Kumar Gala <galak@kernel.crashing.org>
6 * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
8 * Copyright (c) 2008 MontaVista Software, Inc.
9 * Anton Vorontsov <avorontsov@ru.mvista.com>
11 * Note: it appears that you can only actually ENABLE or DISABLE the thing
12 * once after POR. Once enabled, you cannot disable, and vice versa.
14 * This program is free software; you can redistribute it and/or modify it
15 * under the terms of the GNU General Public License as published by the
16 * Free Software Foundation; either version 2 of the License, or (at your
17 * option) any later version.
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
23 #include <linux/init.h>
24 #include <linux/kernel.h>
25 #include <linux/timer.h>
26 #include <linux/miscdevice.h>
27 #include <linux/of_address.h>
28 #include <linux/of_platform.h>
29 #include <linux/module.h>
30 #include <linux/watchdog.h>
32 #include <linux/uaccess.h>
33 #include <sysdev/fsl_soc.h>
37 __be32 swcrr; /* System watchdog control register */
38 #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
39 #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
40 #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
41 #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
42 __be32 swcnr; /* System watchdog count register */
44 __be16 swsrr; /* System watchdog service register */
48 struct mpc8xxx_wdt_type {
53 static struct mpc8xxx_wdt __iomem *wd_base;
55 static u16 timeout = 0xffff;
56 module_param(timeout, ushort, 0);
57 MODULE_PARM_DESC(timeout,
58 "Watchdog timeout in ticks. (0<timeout<65536, default=65535)");
60 static bool reset = 1;
61 module_param(reset, bool, 0);
62 MODULE_PARM_DESC(reset,
63 "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
65 static bool nowayout = WATCHDOG_NOWAYOUT;
66 module_param(nowayout, bool, 0);
67 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
68 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
70 static DEFINE_SPINLOCK(wdt_spinlock);
72 static void mpc8xxx_wdt_keepalive(void)
75 spin_lock(&wdt_spinlock);
76 out_be16(&wd_base->swsrr, 0x556c);
77 out_be16(&wd_base->swsrr, 0xaa39);
78 spin_unlock(&wdt_spinlock);
81 static struct watchdog_device mpc8xxx_wdt_dev;
82 static void mpc8xxx_wdt_timer_ping(unsigned long arg);
83 static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0,
84 (unsigned long)&mpc8xxx_wdt_dev);
86 static void mpc8xxx_wdt_timer_ping(unsigned long arg)
88 struct watchdog_device *w = (struct watchdog_device *)arg;
90 mpc8xxx_wdt_keepalive();
91 /* We're pinging it twice faster than needed, just to be sure. */
92 mod_timer(&wdt_timer, jiffies + HZ * w->timeout / 2);
95 static int mpc8xxx_wdt_start(struct watchdog_device *w)
97 u32 tmp = SWCRR_SWEN | SWCRR_SWPR;
99 /* Good, fire up the show */
103 tmp |= timeout << 16;
105 out_be32(&wd_base->swcrr, tmp);
107 del_timer_sync(&wdt_timer);
112 static int mpc8xxx_wdt_ping(struct watchdog_device *w)
114 mpc8xxx_wdt_keepalive();
118 static int mpc8xxx_wdt_stop(struct watchdog_device *w)
120 mod_timer(&wdt_timer, jiffies);
124 static struct watchdog_info mpc8xxx_wdt_info = {
125 .options = WDIOF_KEEPALIVEPING,
126 .firmware_version = 1,
127 .identity = "MPC8xxx",
130 static struct watchdog_ops mpc8xxx_wdt_ops = {
131 .owner = THIS_MODULE,
132 .start = mpc8xxx_wdt_start,
133 .ping = mpc8xxx_wdt_ping,
134 .stop = mpc8xxx_wdt_stop,
137 static struct watchdog_device mpc8xxx_wdt_dev = {
138 .info = &mpc8xxx_wdt_info,
139 .ops = &mpc8xxx_wdt_ops,
142 static int mpc8xxx_wdt_probe(struct platform_device *ofdev)
145 struct resource *res;
146 const struct mpc8xxx_wdt_type *wdt_type;
147 u32 freq = fsl_get_sys_freq();
149 unsigned int timeout_sec;
151 wdt_type = of_device_get_match_data(&ofdev->dev);
155 if (!freq || freq == -1)
158 res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
159 wd_base = devm_ioremap_resource(&ofdev->dev, res);
161 return PTR_ERR(wd_base);
163 enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
164 if (!enabled && wdt_type->hw_enabled) {
165 pr_info("could not be enabled in software\n");
169 /* Calculate the timeout in seconds */
170 timeout_sec = (timeout * wdt_type->prescaler) / freq;
172 mpc8xxx_wdt_dev.timeout = timeout_sec;
174 watchdog_set_nowayout(&mpc8xxx_wdt_dev, nowayout);
176 ret = watchdog_register_device(&mpc8xxx_wdt_dev);
178 pr_err("cannot register watchdog device (err=%d)\n", ret);
182 pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n",
183 reset ? "reset" : "interrupt", timeout, timeout_sec);
186 * If the watchdog was previously enabled or we're running on
187 * MPC8xxx, we should ping the wdt from the kernel until the
188 * userspace handles it.
191 mod_timer(&wdt_timer, jiffies);
195 static int mpc8xxx_wdt_remove(struct platform_device *ofdev)
197 pr_crit("Watchdog removed, expect the %s soon!\n",
198 reset ? "reset" : "machine check exception");
199 del_timer_sync(&wdt_timer);
200 watchdog_unregister_device(&mpc8xxx_wdt_dev);
205 static const struct of_device_id mpc8xxx_wdt_match[] = {
207 .compatible = "mpc83xx_wdt",
208 .data = &(struct mpc8xxx_wdt_type) {
209 .prescaler = 0x10000,
213 .compatible = "fsl,mpc8610-wdt",
214 .data = &(struct mpc8xxx_wdt_type) {
215 .prescaler = 0x10000,
220 .compatible = "fsl,mpc823-wdt",
221 .data = &(struct mpc8xxx_wdt_type) {
228 MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
230 static struct platform_driver mpc8xxx_wdt_driver = {
231 .probe = mpc8xxx_wdt_probe,
232 .remove = mpc8xxx_wdt_remove,
234 .name = "mpc8xxx_wdt",
235 .of_match_table = mpc8xxx_wdt_match,
239 static int __init mpc8xxx_wdt_init(void)
241 return platform_driver_register(&mpc8xxx_wdt_driver);
243 arch_initcall(mpc8xxx_wdt_init);
245 static void __exit mpc8xxx_wdt_exit(void)
247 platform_driver_unregister(&mpc8xxx_wdt_driver);
249 module_exit(mpc8xxx_wdt_exit);
251 MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
252 MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
254 MODULE_LICENSE("GPL");