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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
Joe Perches27c766a2012-02-15 15:06:19 -080015#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
Kumar Galaa2f40cc2005-09-03 15:55:33 -070017#include <linux/module.h>
18#include <linux/fs.h>
Chen Gongf172ddc2008-04-29 16:42:05 +080019#include <linux/smp.h>
Kumar Galaa2f40cc2005-09-03 15:55:33 -070020#include <linux/miscdevice.h>
21#include <linux/notifier.h>
22#include <linux/watchdog.h>
Alan Cox00e9c202008-05-19 14:06:36 +010023#include <linux/uaccess.h>
Kumar Galaa2f40cc2005-09-03 15:55:33 -070024
25#include <asm/reg_booke.h>
Chris Friesendcfb7482009-08-12 12:02:46 -060026#include <asm/time.h>
27#include <asm/div64.h>
Kumar Galaa2f40cc2005-09-03 15:55:33 -070028
Dave Jiang40ebbcb2007-04-12 13:34:55 -070029/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
Kumar Galaa2f40cc2005-09-03 15:55:33 -070030 * Also, the wdt_period sets the watchdog timer period timeout.
31 * For E500 cpus the wdt_period sets which bit changing from 0->1 will
32 * trigger a watchog timeout. This watchdog timeout will occur 3 times, the
33 * first time nothing will happen, the second time a watchdog exception will
34 * occur, and the final time the board will reset.
35 */
36
Chen Gongf172ddc2008-04-29 16:42:05 +080037u32 booke_wdt_enabled;
Timur Tabie0dc09f2010-10-13 14:19:36 -050038u32 booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT;
Kumar Galaa2f40cc2005-09-03 15:55:33 -070039
40#ifdef CONFIG_FSL_BOOKE
Chris Friesendcfb7482009-08-12 12:02:46 -060041#define WDTP(x) ((((x)&0x3)<<30)|(((x)&0x3c)<<15))
Luuk Paulussen0fb06572010-04-15 15:59:10 +120042#define WDTP_MASK (WDTP(0x3f))
Kumar Galaa2f40cc2005-09-03 15:55:33 -070043#else
44#define WDTP(x) (TCR_WP(x))
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +010045#define WDTP_MASK (TCR_WP_MASK)
Kumar Galaa2f40cc2005-09-03 15:55:33 -070046#endif
47
Chen Gongf172ddc2008-04-29 16:42:05 +080048static DEFINE_SPINLOCK(booke_wdt_lock);
49
Chris Friesendcfb7482009-08-12 12:02:46 -060050/* For the specified period, determine the number of seconds
51 * corresponding to the reset time. There will be a watchdog
52 * exception at approximately 3/5 of this time.
53 *
54 * The formula to calculate this is given by:
55 * 2.5 * (2^(63-period+1)) / timebase_freq
56 *
57 * In order to simplify things, we assume that period is
58 * at least 1. This will still result in a very long timeout.
59 */
60static unsigned long long period_to_sec(unsigned int period)
61{
62 unsigned long long tmp = 1ULL << (64 - period);
63 unsigned long tmp2 = ppc_tb_freq;
64
65 /* tmp may be a very large number and we don't want to overflow,
66 * so divide the timebase freq instead of multiplying tmp
67 */
68 tmp2 = tmp2 / 5 * 2;
69
70 do_div(tmp, tmp2);
71 return tmp;
72}
73
74/*
75 * This procedure will find the highest period which will give a timeout
76 * greater than the one required. e.g. for a bus speed of 66666666 and
77 * and a parameter of 2 secs, then this procedure will return a value of 38.
78 */
79static unsigned int sec_to_period(unsigned int secs)
80{
81 unsigned int period;
82 for (period = 63; period > 0; period--) {
83 if (period_to_sec(period) >= secs)
84 return period;
85 }
86 return 0;
87}
88
Randy Vinson6ae98ed2010-12-06 14:02:23 -070089static void __booke_wdt_set(void *data)
90{
91 u32 val;
92
93 val = mfspr(SPRN_TCR);
94 val &= ~WDTP_MASK;
95 val |= WDTP(booke_wdt_period);
96
97 mtspr(SPRN_TCR, val);
98}
99
100static void booke_wdt_set(void)
101{
102 on_each_cpu(__booke_wdt_set, NULL, 0);
103}
104
Chen Gongf172ddc2008-04-29 16:42:05 +0800105static void __booke_wdt_ping(void *data)
Stefan Roesef31909c2007-02-07 09:45:55 +0100106{
107 mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
108}
109
Chen Gongf172ddc2008-04-29 16:42:05 +0800110static void booke_wdt_ping(void)
111{
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200112 on_each_cpu(__booke_wdt_ping, NULL, 0);
Chen Gongf172ddc2008-04-29 16:42:05 +0800113}
114
115static void __booke_wdt_enable(void *data)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700116{
117 u32 val;
118
Stefan Roesef31909c2007-02-07 09:45:55 +0100119 /* clear status before enabling watchdog */
Chen Gongf172ddc2008-04-29 16:42:05 +0800120 __booke_wdt_ping(NULL);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700121 val = mfspr(SPRN_TCR);
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +0100122 val &= ~WDTP_MASK;
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700123 val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700124
125 mtspr(SPRN_TCR, val);
126}
127
Timur Tabifbdd7142010-09-20 11:23:42 -0500128/**
129 * booke_wdt_disable - disable the watchdog on the given CPU
130 *
131 * This function is called on each CPU. It disables the watchdog on that CPU.
132 *
133 * TCR[WRC] cannot be changed once it has been set to non-zero, but we can
134 * effectively disable the watchdog by setting its period to the maximum value.
135 */
136static void __booke_wdt_disable(void *data)
137{
138 u32 val;
139
140 val = mfspr(SPRN_TCR);
141 val &= ~(TCR_WIE | WDTP_MASK);
142 mtspr(SPRN_TCR, val);
143
144 /* clear status to make sure nothing is pending */
145 __booke_wdt_ping(NULL);
146
147}
148
Chen Gongf172ddc2008-04-29 16:42:05 +0800149static ssize_t booke_wdt_write(struct file *file, const char __user *buf,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700150 size_t count, loff_t *ppos)
151{
152 booke_wdt_ping();
153 return count;
154}
155
Anton Vorontsovd8d8b632010-04-26 15:59:53 -0700156static struct watchdog_info ident = {
Chen Gongf172ddc2008-04-29 16:42:05 +0800157 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
158 .identity = "PowerPC Book-E Watchdog",
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700159};
160
Alan Cox00e9c202008-05-19 14:06:36 +0100161static long booke_wdt_ioctl(struct file *file,
162 unsigned int cmd, unsigned long arg)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700163{
164 u32 tmp = 0;
Al Viro538bacf2005-12-15 09:18:20 +0000165 u32 __user *p = (u32 __user *)arg;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700166
167 switch (cmd) {
168 case WDIOC_GETSUPPORT:
Chris Friesendcfb7482009-08-12 12:02:46 -0600169 if (copy_to_user((void *)arg, &ident, sizeof(ident)))
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700170 return -EFAULT;
171 case WDIOC_GETSTATUS:
Wim Van Sebroeck8b180852010-04-27 08:24:11 +0000172 return put_user(0, p);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700173 case WDIOC_GETBOOTSTATUS:
174 /* XXX: something is clearing TSR */
175 tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
Wim Van Sebroeck8b180852010-04-27 08:24:11 +0000176 /* returns CARDRESET if last reset was caused by the WDT */
177 return (tmp ? WDIOF_CARDRESET : 0);
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000178 case WDIOC_SETOPTIONS:
179 if (get_user(tmp, p))
180 return -EINVAL;
181 if (tmp == WDIOS_ENABLECARD) {
182 booke_wdt_ping();
183 break;
184 } else
185 return -EINVAL;
186 return 0;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700187 case WDIOC_KEEPALIVE:
188 booke_wdt_ping();
189 return 0;
190 case WDIOC_SETTIMEOUT:
Chris Friesendcfb7482009-08-12 12:02:46 -0600191 if (get_user(tmp, p))
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700192 return -EFAULT;
Chris Friesendcfb7482009-08-12 12:02:46 -0600193#ifdef CONFIG_FSL_BOOKE
194 /* period of 1 gives the largest possible timeout */
195 if (tmp > period_to_sec(1))
196 return -EINVAL;
197 booke_wdt_period = sec_to_period(tmp);
198#else
199 booke_wdt_period = tmp;
200#endif
Randy Vinson6ae98ed2010-12-06 14:02:23 -0700201 booke_wdt_set();
Dmitry Artamonow741b9c72012-01-26 23:24:30 +0400202 /* Fall */
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700203 case WDIOC_GETTIMEOUT:
Dmitry Artamonow741b9c72012-01-26 23:24:30 +0400204#ifdef CONFIG_FSL_BOOKE
205 return put_user(period_to_sec(booke_wdt_period), p);
206#else
Al Viro538bacf2005-12-15 09:18:20 +0000207 return put_user(booke_wdt_period, p);
Dmitry Artamonow741b9c72012-01-26 23:24:30 +0400208#endif
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700209 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200210 return -ENOTTY;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700211 }
212
213 return 0;
214}
Chen Gongf172ddc2008-04-29 16:42:05 +0800215
Timur Tabi5d63c132010-12-03 10:51:43 -0600216/* wdt_is_active stores wether or not the /dev/watchdog device is opened */
217static unsigned long wdt_is_active;
218
Chen Gongf172ddc2008-04-29 16:42:05 +0800219static int booke_wdt_open(struct inode *inode, struct file *file)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700220{
Timur Tabi5d63c132010-12-03 10:51:43 -0600221 /* /dev/watchdog can only be opened once */
222 if (test_and_set_bit(0, &wdt_is_active))
223 return -EBUSY;
224
Chen Gongf172ddc2008-04-29 16:42:05 +0800225 spin_lock(&booke_wdt_lock);
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700226 if (booke_wdt_enabled == 0) {
227 booke_wdt_enabled = 1;
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200228 on_each_cpu(__booke_wdt_enable, NULL, 0);
Joe Perches27c766a2012-02-15 15:06:19 -0800229 pr_debug("watchdog enabled (timeout = %llu sec)\n",
230 period_to_sec(booke_wdt_period));
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700231 }
Chen Gongf172ddc2008-04-29 16:42:05 +0800232 spin_unlock(&booke_wdt_lock);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700233
Wim Van Sebroeckec9505a2007-07-20 20:41:37 +0000234 return nonseekable_open(inode, file);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700235}
236
Timur Tabifbdd7142010-09-20 11:23:42 -0500237static int booke_wdt_release(struct inode *inode, struct file *file)
238{
Timur Tabi5d63c132010-12-03 10:51:43 -0600239#ifndef CONFIG_WATCHDOG_NOWAYOUT
240 /* Normally, the watchdog is disabled when /dev/watchdog is closed, but
241 * if CONFIG_WATCHDOG_NOWAYOUT is defined, then it means that the
242 * watchdog should remain enabled. So we disable it only if
243 * CONFIG_WATCHDOG_NOWAYOUT is not defined.
244 */
Timur Tabifbdd7142010-09-20 11:23:42 -0500245 on_each_cpu(__booke_wdt_disable, NULL, 0);
246 booke_wdt_enabled = 0;
Joe Perches27c766a2012-02-15 15:06:19 -0800247 pr_debug("watchdog disabled\n");
Timur Tabi5d63c132010-12-03 10:51:43 -0600248#endif
249
250 clear_bit(0, &wdt_is_active);
Timur Tabifbdd7142010-09-20 11:23:42 -0500251
252 return 0;
253}
254
Arjan van de Ven62322d22006-07-03 00:24:21 -0700255static const struct file_operations booke_wdt_fops = {
Chen Gongf172ddc2008-04-29 16:42:05 +0800256 .owner = THIS_MODULE,
257 .llseek = no_llseek,
258 .write = booke_wdt_write,
Alan Cox00e9c202008-05-19 14:06:36 +0100259 .unlocked_ioctl = booke_wdt_ioctl,
Chen Gongf172ddc2008-04-29 16:42:05 +0800260 .open = booke_wdt_open,
Timur Tabifbdd7142010-09-20 11:23:42 -0500261 .release = booke_wdt_release,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700262};
263
264static struct miscdevice booke_wdt_miscdev = {
Chen Gongf172ddc2008-04-29 16:42:05 +0800265 .minor = WATCHDOG_MINOR,
266 .name = "watchdog",
267 .fops = &booke_wdt_fops,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700268};
269
270static void __exit booke_wdt_exit(void)
271{
272 misc_deregister(&booke_wdt_miscdev);
273}
274
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700275static int __init booke_wdt_init(void)
276{
277 int ret = 0;
278
Joe Perches27c766a2012-02-15 15:06:19 -0800279 pr_info("powerpc book-e watchdog driver loaded\n");
Al Viroa78719c2005-12-16 22:35:28 +0000280 ident.firmware_version = cur_cpu_spec->pvr_value;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700281
282 ret = misc_register(&booke_wdt_miscdev);
283 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800284 pr_err("cannot register device (minor=%u, ret=%i)\n",
Timur Tabi112e7542011-02-08 17:39:46 -0600285 WATCHDOG_MINOR, ret);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700286 return ret;
287 }
288
Chen Gongf172ddc2008-04-29 16:42:05 +0800289 spin_lock(&booke_wdt_lock);
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700290 if (booke_wdt_enabled == 1) {
Joe Perches27c766a2012-02-15 15:06:19 -0800291 pr_info("watchdog enabled (timeout = %llu sec)\n",
Timur Tabi112e7542011-02-08 17:39:46 -0600292 period_to_sec(booke_wdt_period));
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200293 on_each_cpu(__booke_wdt_enable, NULL, 0);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700294 }
Chen Gongf172ddc2008-04-29 16:42:05 +0800295 spin_unlock(&booke_wdt_lock);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700296
297 return ret;
298}
Timur Tabifbdd7142010-09-20 11:23:42 -0500299
300module_init(booke_wdt_init);
301module_exit(booke_wdt_exit);
302
303MODULE_DESCRIPTION("PowerPC Book-E watchdog driver");
304MODULE_LICENSE("GPL");