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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 *
Chen Gongf172ddc62008-04-29 16:42:05 +08007 * Copyright 2005, 2008 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 Gongf172ddc62008-04-29 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
36#ifdef CONFIG_FSL_BOOKE
Chris Friesendcfb7482009-08-12 12:02:46 -060037#define WDT_PERIOD_DEFAULT 38 /* Ex. wdt_period=28 bus=333Mhz,reset=~40sec */
Kumar Galaa2f40cc2005-09-03 15:55:33 -070038#else
Stefan Roesef31909c2007-02-07 09:45:55 +010039#define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */
Kumar Galaa2f40cc2005-09-03 15:55:33 -070040#endif /* for timing information */
41
Chen Gongf172ddc62008-04-29 16:42:05 +080042u32 booke_wdt_enabled;
Kumar Gala39cdc4b2005-09-03 15:55:39 -070043u32 booke_wdt_period = WDT_PERIOD_DEFAULT;
Kumar Galaa2f40cc2005-09-03 15:55:33 -070044
45#ifdef CONFIG_FSL_BOOKE
Chris Friesendcfb7482009-08-12 12:02:46 -060046#define WDTP(x) ((((x)&0x3)<<30)|(((x)&0x3c)<<15))
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +010047#define WDTP_MASK (WDTP(0))
Kumar Galaa2f40cc2005-09-03 15:55:33 -070048#else
49#define WDTP(x) (TCR_WP(x))
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +010050#define WDTP_MASK (TCR_WP_MASK)
Kumar Galaa2f40cc2005-09-03 15:55:33 -070051#endif
52
Chen Gongf172ddc62008-04-29 16:42:05 +080053static DEFINE_SPINLOCK(booke_wdt_lock);
54
Chris Friesendcfb7482009-08-12 12:02:46 -060055/* For the specified period, determine the number of seconds
56 * corresponding to the reset time. There will be a watchdog
57 * exception at approximately 3/5 of this time.
58 *
59 * The formula to calculate this is given by:
60 * 2.5 * (2^(63-period+1)) / timebase_freq
61 *
62 * In order to simplify things, we assume that period is
63 * at least 1. This will still result in a very long timeout.
64 */
65static unsigned long long period_to_sec(unsigned int period)
66{
67 unsigned long long tmp = 1ULL << (64 - period);
68 unsigned long tmp2 = ppc_tb_freq;
69
70 /* tmp may be a very large number and we don't want to overflow,
71 * so divide the timebase freq instead of multiplying tmp
72 */
73 tmp2 = tmp2 / 5 * 2;
74
75 do_div(tmp, tmp2);
76 return tmp;
77}
78
79/*
80 * This procedure will find the highest period which will give a timeout
81 * greater than the one required. e.g. for a bus speed of 66666666 and
82 * and a parameter of 2 secs, then this procedure will return a value of 38.
83 */
84static unsigned int sec_to_period(unsigned int secs)
85{
86 unsigned int period;
87 for (period = 63; period > 0; period--) {
88 if (period_to_sec(period) >= secs)
89 return period;
90 }
91 return 0;
92}
93
Chen Gongf172ddc62008-04-29 16:42:05 +080094static void __booke_wdt_ping(void *data)
Stefan Roesef31909c2007-02-07 09:45:55 +010095{
96 mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
97}
98
Chen Gongf172ddc62008-04-29 16:42:05 +080099static void booke_wdt_ping(void)
100{
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200101 on_each_cpu(__booke_wdt_ping, NULL, 0);
Chen Gongf172ddc62008-04-29 16:42:05 +0800102}
103
104static void __booke_wdt_enable(void *data)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700105{
106 u32 val;
107
Stefan Roesef31909c2007-02-07 09:45:55 +0100108 /* clear status before enabling watchdog */
Chen Gongf172ddc62008-04-29 16:42:05 +0800109 __booke_wdt_ping(NULL);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700110 val = mfspr(SPRN_TCR);
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +0100111 val &= ~WDTP_MASK;
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700112 val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700113
114 mtspr(SPRN_TCR, val);
115}
116
Chen Gongf172ddc62008-04-29 16:42:05 +0800117static ssize_t booke_wdt_write(struct file *file, const char __user *buf,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700118 size_t count, loff_t *ppos)
119{
120 booke_wdt_ping();
121 return count;
122}
123
124static struct watchdog_info ident = {
Chen Gongf172ddc62008-04-29 16:42:05 +0800125 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
126 .identity = "PowerPC Book-E Watchdog",
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700127};
128
Alan Cox00e9c202008-05-19 14:06:36 +0100129static long booke_wdt_ioctl(struct file *file,
130 unsigned int cmd, unsigned long arg)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700131{
132 u32 tmp = 0;
Al Viro538bacf2005-12-15 09:18:20 +0000133 u32 __user *p = (u32 __user *)arg;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700134
135 switch (cmd) {
136 case WDIOC_GETSUPPORT:
Chris Friesendcfb7482009-08-12 12:02:46 -0600137 if (copy_to_user((void *)arg, &ident, sizeof(ident)))
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700138 return -EFAULT;
139 case WDIOC_GETSTATUS:
Al Viro538bacf2005-12-15 09:18:20 +0000140 return put_user(ident.options, p);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700141 case WDIOC_GETBOOTSTATUS:
142 /* XXX: something is clearing TSR */
143 tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
144 /* returns 1 if last reset was caused by the WDT */
145 return (tmp ? 1 : 0);
Wim Van Sebroeck0c060902008-07-18 11:41:17 +0000146 case WDIOC_SETOPTIONS:
147 if (get_user(tmp, p))
148 return -EINVAL;
149 if (tmp == WDIOS_ENABLECARD) {
150 booke_wdt_ping();
151 break;
152 } else
153 return -EINVAL;
154 return 0;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700155 case WDIOC_KEEPALIVE:
156 booke_wdt_ping();
157 return 0;
158 case WDIOC_SETTIMEOUT:
Chris Friesendcfb7482009-08-12 12:02:46 -0600159 if (get_user(tmp, p))
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700160 return -EFAULT;
Chris Friesendcfb7482009-08-12 12:02:46 -0600161#ifdef CONFIG_FSL_BOOKE
162 /* period of 1 gives the largest possible timeout */
163 if (tmp > period_to_sec(1))
164 return -EINVAL;
165 booke_wdt_period = sec_to_period(tmp);
166#else
167 booke_wdt_period = tmp;
168#endif
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +0100169 mtspr(SPRN_TCR, (mfspr(SPRN_TCR) & ~WDTP_MASK) |
Alan Cox00e9c202008-05-19 14:06:36 +0100170 WDTP(booke_wdt_period));
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700171 return 0;
172 case WDIOC_GETTIMEOUT:
Al Viro538bacf2005-12-15 09:18:20 +0000173 return put_user(booke_wdt_period, p);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700174 default:
Samuel Tardieu795b89d2006-09-09 17:34:31 +0200175 return -ENOTTY;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700176 }
177
178 return 0;
179}
Chen Gongf172ddc62008-04-29 16:42:05 +0800180
181static int booke_wdt_open(struct inode *inode, struct file *file)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700182{
Chen Gongf172ddc62008-04-29 16:42:05 +0800183 spin_lock(&booke_wdt_lock);
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700184 if (booke_wdt_enabled == 0) {
185 booke_wdt_enabled = 1;
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200186 on_each_cpu(__booke_wdt_enable, NULL, 0);
Alan Cox00e9c202008-05-19 14:06:36 +0100187 printk(KERN_INFO
188 "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
189 booke_wdt_period);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700190 }
Chen Gongf172ddc62008-04-29 16:42:05 +0800191 spin_unlock(&booke_wdt_lock);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700192
Wim Van Sebroeckec9505a2007-07-20 20:41:37 +0000193 return nonseekable_open(inode, file);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700194}
195
Arjan van de Ven62322d22006-07-03 00:24:21 -0700196static const struct file_operations booke_wdt_fops = {
Chen Gongf172ddc62008-04-29 16:42:05 +0800197 .owner = THIS_MODULE,
198 .llseek = no_llseek,
199 .write = booke_wdt_write,
Alan Cox00e9c202008-05-19 14:06:36 +0100200 .unlocked_ioctl = booke_wdt_ioctl,
Chen Gongf172ddc62008-04-29 16:42:05 +0800201 .open = booke_wdt_open,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700202};
203
204static struct miscdevice booke_wdt_miscdev = {
Chen Gongf172ddc62008-04-29 16:42:05 +0800205 .minor = WATCHDOG_MINOR,
206 .name = "watchdog",
207 .fops = &booke_wdt_fops,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700208};
209
210static void __exit booke_wdt_exit(void)
211{
212 misc_deregister(&booke_wdt_miscdev);
213}
214
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700215static int __init booke_wdt_init(void)
216{
217 int ret = 0;
218
Chen Gongf172ddc62008-04-29 16:42:05 +0800219 printk(KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n");
Al Viroa78719c2005-12-16 22:35:28 +0000220 ident.firmware_version = cur_cpu_spec->pvr_value;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700221
222 ret = misc_register(&booke_wdt_miscdev);
223 if (ret) {
Chen Gongf172ddc62008-04-29 16:42:05 +0800224 printk(KERN_CRIT "Cannot register miscdev on minor=%d: %d\n",
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700225 WATCHDOG_MINOR, ret);
226 return ret;
227 }
228
Chen Gongf172ddc62008-04-29 16:42:05 +0800229 spin_lock(&booke_wdt_lock);
Kumar Gala39cdc4b2005-09-03 15:55:39 -0700230 if (booke_wdt_enabled == 1) {
Alan Cox00e9c202008-05-19 14:06:36 +0100231 printk(KERN_INFO
232 "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n",
233 booke_wdt_period);
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200234 on_each_cpu(__booke_wdt_enable, NULL, 0);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700235 }
Chen Gongf172ddc62008-04-29 16:42:05 +0800236 spin_unlock(&booke_wdt_lock);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700237
238 return ret;
239}
240device_initcall(booke_wdt_init);