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Kumar Galaa2f40cc2005-09-03 15:55:33 -07001/*
Kumar Galaa2f40cc2005-09-03 15:55:33 -07002 * Watchdog timer for PowerPC Book-E systems
3 *
4 * Author: Matthew McClintock
Kumar Gala4c8d3d92005-11-13 16:06:30 -08005 * Maintainer: Kumar Gala <galak@kernel.crashing.org>
Kumar Galaa2f40cc2005-09-03 15:55:33 -07006 *
Timur Tabi112e7542011-02-08 17:39:46 -06007 * Copyright 2005, 2008, 2010-2011 Freescale Semiconductor Inc.
Kumar Galaa2f40cc2005-09-03 15:55:33 -07008 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the
11 * Free Software Foundation; either version 2 of the License, or (at your
12 * option) any later version.
13 */
14
Kumar Galaa2f40cc2005-09-03 15:55:33 -070015#include <linux/module.h>
16#include <linux/fs.h>
Chen Gongf172ddc2008-04-29 16:42:05 +080017#include <linux/smp.h>
Kumar Galaa2f40cc2005-09-03 15:55:33 -070018#include <linux/miscdevice.h>
19#include <linux/notifier.h>
20#include <linux/watchdog.h>
Alan Cox00e9c202008-05-19 14:06:36 +010021#include <linux/uaccess.h>
Kumar Galaa2f40cc2005-09-03 15:55:33 -070022
23#include <asm/reg_booke.h>
Kumar Gala39cdc4b2005-09-03 15:55:39 -070024#include <asm/system.h>
Chris Friesendcfb7482009-08-12 12:02:46 -060025#include <asm/time.h>
26#include <asm/div64.h>
Kumar Galaa2f40cc2005-09-03 15:55:33 -070027
Dave Jiang40ebbcb2007-04-12 13:34:55 -070028/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
Kumar Galaa2f40cc2005-09-03 15:55:33 -070029 * Also, the wdt_period sets the watchdog timer period timeout.
30 * For E500 cpus the wdt_period sets which bit changing from 0->1 will
31 * trigger a watchog timeout. This watchdog timeout will occur 3 times, the
32 * first time nothing will happen, the second time a watchdog exception will
33 * occur, and the final time the board will reset.
34 */
35
Chen Gongf172ddc2008-04-29 16:42:05 +080036u32 booke_wdt_enabled;
Timur Tabie0dc09f2010-10-13 14:19:36 -050037u32 booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT;
Kumar Galaa2f40cc2005-09-03 15:55:33 -070038
39#ifdef CONFIG_FSL_BOOKE
Chris Friesendcfb7482009-08-12 12:02:46 -060040#define WDTP(x) ((((x)&0x3)<<30)|(((x)&0x3c)<<15))
Luuk Paulussen0fb06572010-04-15 15:59:10 +120041#define WDTP_MASK (WDTP(0x3f))
Kumar Galaa2f40cc2005-09-03 15:55:33 -070042#else
43#define WDTP(x) (TCR_WP(x))
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +010044#define WDTP_MASK (TCR_WP_MASK)
Kumar Galaa2f40cc2005-09-03 15:55:33 -070045#endif
46
Chen Gongf172ddc2008-04-29 16:42:05 +080047static DEFINE_SPINLOCK(booke_wdt_lock);
48
Chris Friesendcfb7482009-08-12 12:02:46 -060049/* For the specified period, determine the number of seconds
50 * corresponding to the reset time. There will be a watchdog
51 * exception at approximately 3/5 of this time.
52 *
53 * The formula to calculate this is given by:
54 * 2.5 * (2^(63-period+1)) / timebase_freq
55 *
56 * In order to simplify things, we assume that period is
57 * at least 1. This will still result in a very long timeout.
58 */
59static unsigned long long period_to_sec(unsigned int period)
60{
61 unsigned long long tmp = 1ULL << (64 - period);
62 unsigned long tmp2 = ppc_tb_freq;
63
64 /* tmp may be a very large number and we don't want to overflow,
65 * so divide the timebase freq instead of multiplying tmp
66 */
67 tmp2 = tmp2 / 5 * 2;
68
69 do_div(tmp, tmp2);
70 return tmp;
71}
72
73/*
74 * This procedure will find the highest period which will give a timeout
75 * greater than the one required. e.g. for a bus speed of 66666666 and
76 * and a parameter of 2 secs, then this procedure will return a value of 38.
77 */
78static unsigned int sec_to_period(unsigned int secs)
79{
80 unsigned int period;
81 for (period = 63; period > 0; period--) {
82 if (period_to_sec(period) >= secs)
83 return period;
84 }
85 return 0;
86}
87
Randy Vinson6ae98ed2010-12-06 14:02:23 -070088static void __booke_wdt_set(void *data)
89{
90 u32 val;
91
92 val = mfspr(SPRN_TCR);
93 val &= ~WDTP_MASK;
94 val |= WDTP(booke_wdt_period);
95
96 mtspr(SPRN_TCR, val);
97}
98
99static void booke_wdt_set(void)
100{
101 on_each_cpu(__booke_wdt_set, NULL, 0);
102}
103
Chen Gongf172ddc2008-04-29 16:42:05 +0800104static void __booke_wdt_ping(void *data)
Stefan Roesef31909c2007-02-07 09:45:55 +0100105{
106 mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
107}
108
Chen Gongf172ddc2008-04-29 16:42:05 +0800109static void booke_wdt_ping(void)
110{
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200111 on_each_cpu(__booke_wdt_ping, NULL, 0);
Chen Gongf172ddc2008-04-29 16:42:05 +0800112}
113
114static void __booke_wdt_enable(void *data)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700115{
116 u32 val;
117
Stefan Roesef31909c2007-02-07 09:45:55 +0100118 /* clear status before enabling watchdog */
Chen Gongf172ddc2008-04-29 16:42:05 +0800119 __booke_wdt_ping(NULL);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700120 val = mfspr(SPRN_TCR);
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +0100121 val &= ~WDTP_MASK;
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700122 val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700123
124 mtspr(SPRN_TCR, val);
125}
126
Timur Tabifbdd7142010-09-20 11:23:42 -0500127/**
128 * booke_wdt_disable - disable the watchdog on the given CPU
129 *
130 * This function is called on each CPU. It disables the watchdog on that CPU.
131 *
132 * TCR[WRC] cannot be changed once it has been set to non-zero, but we can
133 * effectively disable the watchdog by setting its period to the maximum value.
134 */
135static void __booke_wdt_disable(void *data)
136{
137 u32 val;
138
139 val = mfspr(SPRN_TCR);
140 val &= ~(TCR_WIE | WDTP_MASK);
141 mtspr(SPRN_TCR, val);
142
143 /* clear status to make sure nothing is pending */
144 __booke_wdt_ping(NULL);
145
146}
147
Chen Gongf172ddc2008-04-29 16:42:05 +0800148static ssize_t booke_wdt_write(struct file *file, const char __user *buf,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700149 size_t count, loff_t *ppos)
150{
151 booke_wdt_ping();
152 return count;
153}
154
Anton Vorontsovd8d8b632010-04-26 15:59:53 -0700155static struct watchdog_info ident = {
Chen Gongf172ddc2008-04-29 16:42:05 +0800156 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
157 .identity = "PowerPC Book-E Watchdog",
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700158};
159
Alan Cox00e9c202008-05-19 14:06:36 +0100160static long booke_wdt_ioctl(struct file *file,
161 unsigned int cmd, unsigned long arg)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700162{
163 u32 tmp = 0;
Al Viro538bacf2005-12-15 09:18:20 +0000164 u32 __user *p = (u32 __user *)arg;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700165
166 switch (cmd) {
167 case WDIOC_GETSUPPORT:
Chris Friesendcfb7482009-08-12 12:02:46 -0600168 if (copy_to_user((void *)arg, &ident, sizeof(ident)))
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700169 return -EFAULT;
170 case WDIOC_GETSTATUS:
Wim Van Sebroeck8b180852010-04-27 08:24:11 +0000171 return put_user(0, p);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700172 case WDIOC_GETBOOTSTATUS:
173 /* XXX: something is clearing TSR */
174 tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
Wim Van Sebroeck8b180852010-04-27 08:24:11 +0000175 /* returns CARDRESET if last reset was caused by the WDT */
176 return (tmp ? WDIOF_CARDRESET : 0);
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000177 case WDIOC_SETOPTIONS:
178 if (get_user(tmp, p))
179 return -EINVAL;
180 if (tmp == WDIOS_ENABLECARD) {
181 booke_wdt_ping();
182 break;
183 } else
184 return -EINVAL;
185 return 0;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700186 case WDIOC_KEEPALIVE:
187 booke_wdt_ping();
188 return 0;
189 case WDIOC_SETTIMEOUT:
Chris Friesendcfb7482009-08-12 12:02:46 -0600190 if (get_user(tmp, p))
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700191 return -EFAULT;
Chris Friesendcfb7482009-08-12 12:02:46 -0600192#ifdef CONFIG_FSL_BOOKE
193 /* period of 1 gives the largest possible timeout */
194 if (tmp > period_to_sec(1))
195 return -EINVAL;
196 booke_wdt_period = sec_to_period(tmp);
197#else
198 booke_wdt_period = tmp;
199#endif
Randy Vinson6ae98ed2010-12-06 14:02:23 -0700200 booke_wdt_set();
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700201 return 0;
202 case WDIOC_GETTIMEOUT:
Al Viro538bacf2005-12-15 09:18:20 +0000203 return put_user(booke_wdt_period, p);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700204 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200205 return -ENOTTY;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700206 }
207
208 return 0;
209}
Chen Gongf172ddc2008-04-29 16:42:05 +0800210
Timur Tabi5d63c132010-12-03 10:51:43 -0600211/* wdt_is_active stores wether or not the /dev/watchdog device is opened */
212static unsigned long wdt_is_active;
213
Chen Gongf172ddc2008-04-29 16:42:05 +0800214static int booke_wdt_open(struct inode *inode, struct file *file)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700215{
Timur Tabi5d63c132010-12-03 10:51:43 -0600216 /* /dev/watchdog can only be opened once */
217 if (test_and_set_bit(0, &wdt_is_active))
218 return -EBUSY;
219
Chen Gongf172ddc2008-04-29 16:42:05 +0800220 spin_lock(&booke_wdt_lock);
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700221 if (booke_wdt_enabled == 0) {
222 booke_wdt_enabled = 1;
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200223 on_each_cpu(__booke_wdt_enable, NULL, 0);
Timur Tabi112e7542011-02-08 17:39:46 -0600224 pr_debug("booke_wdt: watchdog enabled (timeout = %llu sec)\n",
225 period_to_sec(booke_wdt_period));
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700226 }
Chen Gongf172ddc2008-04-29 16:42:05 +0800227 spin_unlock(&booke_wdt_lock);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700228
Wim Van Sebroeckec9505a2007-07-20 20:41:37 +0000229 return nonseekable_open(inode, file);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700230}
231
Timur Tabifbdd7142010-09-20 11:23:42 -0500232static int booke_wdt_release(struct inode *inode, struct file *file)
233{
Timur Tabi5d63c132010-12-03 10:51:43 -0600234#ifndef CONFIG_WATCHDOG_NOWAYOUT
235 /* Normally, the watchdog is disabled when /dev/watchdog is closed, but
236 * if CONFIG_WATCHDOG_NOWAYOUT is defined, then it means that the
237 * watchdog should remain enabled. So we disable it only if
238 * CONFIG_WATCHDOG_NOWAYOUT is not defined.
239 */
Timur Tabifbdd7142010-09-20 11:23:42 -0500240 on_each_cpu(__booke_wdt_disable, NULL, 0);
241 booke_wdt_enabled = 0;
Timur Tabi112e7542011-02-08 17:39:46 -0600242 pr_debug("booke_wdt: watchdog disabled\n");
Timur Tabi5d63c132010-12-03 10:51:43 -0600243#endif
244
245 clear_bit(0, &wdt_is_active);
Timur Tabifbdd7142010-09-20 11:23:42 -0500246
247 return 0;
248}
249
Arjan van de Ven62322d22006-07-03 00:24:21 -0700250static const struct file_operations booke_wdt_fops = {
Chen Gongf172ddc2008-04-29 16:42:05 +0800251 .owner = THIS_MODULE,
252 .llseek = no_llseek,
253 .write = booke_wdt_write,
Alan Cox00e9c202008-05-19 14:06:36 +0100254 .unlocked_ioctl = booke_wdt_ioctl,
Chen Gongf172ddc2008-04-29 16:42:05 +0800255 .open = booke_wdt_open,
Timur Tabifbdd7142010-09-20 11:23:42 -0500256 .release = booke_wdt_release,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700257};
258
259static struct miscdevice booke_wdt_miscdev = {
Chen Gongf172ddc2008-04-29 16:42:05 +0800260 .minor = WATCHDOG_MINOR,
261 .name = "watchdog",
262 .fops = &booke_wdt_fops,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700263};
264
265static void __exit booke_wdt_exit(void)
266{
267 misc_deregister(&booke_wdt_miscdev);
268}
269
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700270static int __init booke_wdt_init(void)
271{
272 int ret = 0;
273
Timur Tabi112e7542011-02-08 17:39:46 -0600274 pr_info("booke_wdt: powerpc book-e watchdog driver loaded\n");
Al Viroa78719c2005-12-16 22:35:28 +0000275 ident.firmware_version = cur_cpu_spec->pvr_value;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700276
277 ret = misc_register(&booke_wdt_miscdev);
278 if (ret) {
Timur Tabi112e7542011-02-08 17:39:46 -0600279 pr_err("booke_wdt: cannot register device (minor=%u, ret=%i)\n",
280 WATCHDOG_MINOR, ret);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700281 return ret;
282 }
283
Chen Gongf172ddc2008-04-29 16:42:05 +0800284 spin_lock(&booke_wdt_lock);
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700285 if (booke_wdt_enabled == 1) {
Timur Tabi112e7542011-02-08 17:39:46 -0600286 pr_info("booke_wdt: watchdog enabled (timeout = %llu sec)\n",
287 period_to_sec(booke_wdt_period));
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200288 on_each_cpu(__booke_wdt_enable, NULL, 0);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700289 }
Chen Gongf172ddc2008-04-29 16:42:05 +0800290 spin_unlock(&booke_wdt_lock);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700291
292 return ret;
293}
Timur Tabifbdd7142010-09-20 11:23:42 -0500294
295module_init(booke_wdt_init);
296module_exit(booke_wdt_exit);
297
298MODULE_DESCRIPTION("PowerPC Book-E watchdog driver");
299MODULE_LICENSE("GPL");