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/of_address.h>
27 #include <linux/of_platform.h>
28 #include <linux/module.h>
29 #include <linux/watchdog.h>
31 #include <linux/uaccess.h>
32 #include <sysdev/fsl_soc.h>
36 __be32 swcrr; /* System watchdog control register */
37 #define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
38 #define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
39 #define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
40 #define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
41 __be32 swcnr; /* System watchdog count register */
43 __be16 swsrr; /* System watchdog service register */
47 struct mpc8xxx_wdt_type {
52 struct mpc8xxx_wdt_ddata {
53 struct mpc8xxx_wdt __iomem *base;
54 struct watchdog_device wdd;
55 struct timer_list timer;
59 static u16 timeout = 0xffff;
60 module_param(timeout, ushort, 0);
61 MODULE_PARM_DESC(timeout,
62 "Watchdog timeout in ticks. (0<timeout<65536, default=65535)");
64 static bool reset = 1;
65 module_param(reset, bool, 0);
66 MODULE_PARM_DESC(reset,
67 "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
69 static bool nowayout = WATCHDOG_NOWAYOUT;
70 module_param(nowayout, bool, 0);
71 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
72 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
74 static void mpc8xxx_wdt_keepalive(struct mpc8xxx_wdt_ddata *ddata)
77 spin_lock(&ddata->lock);
78 out_be16(&ddata->base->swsrr, 0x556c);
79 out_be16(&ddata->base->swsrr, 0xaa39);
80 spin_unlock(&ddata->lock);
83 static void mpc8xxx_wdt_timer_ping(struct timer_list *t)
85 struct mpc8xxx_wdt_ddata *ddata = from_timer(ddata, t, timer);
87 mpc8xxx_wdt_keepalive(ddata);
88 /* We're pinging it twice faster than needed, just to be sure. */
89 mod_timer(&ddata->timer, jiffies + HZ * ddata->wdd.timeout / 2);
92 static int mpc8xxx_wdt_start(struct watchdog_device *w)
94 struct mpc8xxx_wdt_ddata *ddata =
95 container_of(w, struct mpc8xxx_wdt_ddata, wdd);
97 u32 tmp = SWCRR_SWEN | SWCRR_SWPR;
99 /* Good, fire up the show */
103 tmp |= timeout << 16;
105 out_be32(&ddata->base->swcrr, tmp);
107 del_timer_sync(&ddata->timer);
112 static int mpc8xxx_wdt_ping(struct watchdog_device *w)
114 struct mpc8xxx_wdt_ddata *ddata =
115 container_of(w, struct mpc8xxx_wdt_ddata, wdd);
117 mpc8xxx_wdt_keepalive(ddata);
121 static int mpc8xxx_wdt_stop(struct watchdog_device *w)
123 struct mpc8xxx_wdt_ddata *ddata =
124 container_of(w, struct mpc8xxx_wdt_ddata, wdd);
126 mod_timer(&ddata->timer, jiffies);
130 static struct watchdog_info mpc8xxx_wdt_info = {
131 .options = WDIOF_KEEPALIVEPING,
132 .firmware_version = 1,
133 .identity = "MPC8xxx",
136 static struct watchdog_ops mpc8xxx_wdt_ops = {
137 .owner = THIS_MODULE,
138 .start = mpc8xxx_wdt_start,
139 .ping = mpc8xxx_wdt_ping,
140 .stop = mpc8xxx_wdt_stop,
143 static int mpc8xxx_wdt_probe(struct platform_device *ofdev)
146 struct resource *res;
147 const struct mpc8xxx_wdt_type *wdt_type;
148 struct mpc8xxx_wdt_ddata *ddata;
149 u32 freq = fsl_get_sys_freq();
151 unsigned int timeout_sec;
153 wdt_type = of_device_get_match_data(&ofdev->dev);
157 if (!freq || freq == -1)
160 ddata = devm_kzalloc(&ofdev->dev, sizeof(*ddata), GFP_KERNEL);
164 res = platform_get_resource(ofdev, IORESOURCE_MEM, 0);
165 ddata->base = devm_ioremap_resource(&ofdev->dev, res);
166 if (IS_ERR(ddata->base))
167 return PTR_ERR(ddata->base);
169 enabled = in_be32(&ddata->base->swcrr) & SWCRR_SWEN;
170 if (!enabled && wdt_type->hw_enabled) {
171 pr_info("could not be enabled in software\n");
175 spin_lock_init(&ddata->lock);
176 timer_setup(&ddata->timer, mpc8xxx_wdt_timer_ping, 0);
178 ddata->wdd.info = &mpc8xxx_wdt_info,
179 ddata->wdd.ops = &mpc8xxx_wdt_ops,
181 /* Calculate the timeout in seconds */
182 timeout_sec = (timeout * wdt_type->prescaler) / freq;
184 ddata->wdd.timeout = timeout_sec;
186 watchdog_set_nowayout(&ddata->wdd, nowayout);
188 ret = watchdog_register_device(&ddata->wdd);
190 pr_err("cannot register watchdog device (err=%d)\n", ret);
194 pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n",
195 reset ? "reset" : "interrupt", timeout, timeout_sec);
198 * If the watchdog was previously enabled or we're running on
199 * MPC8xxx, we should ping the wdt from the kernel until the
200 * userspace handles it.
203 mod_timer(&ddata->timer, jiffies);
205 platform_set_drvdata(ofdev, ddata);
209 static int mpc8xxx_wdt_remove(struct platform_device *ofdev)
211 struct mpc8xxx_wdt_ddata *ddata = platform_get_drvdata(ofdev);
213 pr_crit("Watchdog removed, expect the %s soon!\n",
214 reset ? "reset" : "machine check exception");
215 del_timer_sync(&ddata->timer);
216 watchdog_unregister_device(&ddata->wdd);
221 static const struct of_device_id mpc8xxx_wdt_match[] = {
223 .compatible = "mpc83xx_wdt",
224 .data = &(struct mpc8xxx_wdt_type) {
225 .prescaler = 0x10000,
229 .compatible = "fsl,mpc8610-wdt",
230 .data = &(struct mpc8xxx_wdt_type) {
231 .prescaler = 0x10000,
236 .compatible = "fsl,mpc823-wdt",
237 .data = &(struct mpc8xxx_wdt_type) {
244 MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
246 static struct platform_driver mpc8xxx_wdt_driver = {
247 .probe = mpc8xxx_wdt_probe,
248 .remove = mpc8xxx_wdt_remove,
250 .name = "mpc8xxx_wdt",
251 .of_match_table = mpc8xxx_wdt_match,
255 static int __init mpc8xxx_wdt_init(void)
257 return platform_driver_register(&mpc8xxx_wdt_driver);
259 arch_initcall(mpc8xxx_wdt_init);
261 static void __exit mpc8xxx_wdt_exit(void)
263 platform_driver_unregister(&mpc8xxx_wdt_driver);
265 module_exit(mpc8xxx_wdt_exit);
267 MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
268 MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
270 MODULE_LICENSE("GPL");