Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 1 | /* |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 2 | * Watchdog timer for PowerPC Book-E systems |
| 3 | * |
| 4 | * Author: Matthew McClintock |
Kumar Gala | 4c8d3d9 | 2005-11-13 16:06:30 -0800 | [diff] [blame] | 5 | * Maintainer: Kumar Gala <galak@kernel.crashing.org> |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 6 | * |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 7 | * Copyright 2005, 2008 Freescale Semiconductor Inc. |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 8 | * |
| 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 Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 15 | #include <linux/module.h> |
| 16 | #include <linux/fs.h> |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 17 | #include <linux/smp.h> |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 18 | #include <linux/miscdevice.h> |
| 19 | #include <linux/notifier.h> |
| 20 | #include <linux/watchdog.h> |
Alan Cox | 00e9c20 | 2008-05-19 14:06:36 +0100 | [diff] [blame] | 21 | #include <linux/uaccess.h> |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 22 | |
| 23 | #include <asm/reg_booke.h> |
Kumar Gala | 39cdc4b | 2005-09-03 15:55:39 -0700 | [diff] [blame] | 24 | #include <asm/system.h> |
Chris Friesen | dcfb748 | 2009-08-12 12:02:46 -0600 | [diff] [blame] | 25 | #include <asm/time.h> |
| 26 | #include <asm/div64.h> |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 27 | |
Dave Jiang | 40ebbcb | 2007-04-12 13:34:55 -0700 | [diff] [blame] | 28 | /* If the kernel parameter wdt=1, the watchdog will be enabled at boot. |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 29 | * 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 Friesen | dcfb748 | 2009-08-12 12:02:46 -0600 | [diff] [blame] | 37 | #define WDT_PERIOD_DEFAULT 38 /* Ex. wdt_period=28 bus=333Mhz,reset=~40sec */ |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 38 | #else |
Stefan Roese | f31909c | 2007-02-07 09:45:55 +0100 | [diff] [blame] | 39 | #define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */ |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 40 | #endif /* for timing information */ |
| 41 | |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 42 | u32 booke_wdt_enabled; |
Kumar Gala | 39cdc4b | 2005-09-03 15:55:39 -0700 | [diff] [blame] | 43 | u32 booke_wdt_period = WDT_PERIOD_DEFAULT; |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 44 | |
| 45 | #ifdef CONFIG_FSL_BOOKE |
Chris Friesen | dcfb748 | 2009-08-12 12:02:46 -0600 | [diff] [blame] | 46 | #define WDTP(x) ((((x)&0x3)<<30)|(((x)&0x3c)<<15)) |
Matthias Fuchs | 0a0e9e0 | 2008-11-05 21:53:56 +0100 | [diff] [blame] | 47 | #define WDTP_MASK (WDTP(0)) |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 48 | #else |
| 49 | #define WDTP(x) (TCR_WP(x)) |
Matthias Fuchs | 0a0e9e0 | 2008-11-05 21:53:56 +0100 | [diff] [blame] | 50 | #define WDTP_MASK (TCR_WP_MASK) |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 51 | #endif |
| 52 | |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 53 | static DEFINE_SPINLOCK(booke_wdt_lock); |
| 54 | |
Chris Friesen | dcfb748 | 2009-08-12 12:02:46 -0600 | [diff] [blame] | 55 | /* 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 | */ |
| 65 | static 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 | */ |
| 84 | static 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 Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 94 | static void __booke_wdt_ping(void *data) |
Stefan Roese | f31909c | 2007-02-07 09:45:55 +0100 | [diff] [blame] | 95 | { |
| 96 | mtspr(SPRN_TSR, TSR_ENW|TSR_WIS); |
| 97 | } |
| 98 | |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 99 | static void booke_wdt_ping(void) |
| 100 | { |
Ingo Molnar | f6f88e9 | 2008-07-15 22:08:52 +0200 | [diff] [blame] | 101 | on_each_cpu(__booke_wdt_ping, NULL, 0); |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 102 | } |
| 103 | |
| 104 | static void __booke_wdt_enable(void *data) |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 105 | { |
| 106 | u32 val; |
| 107 | |
Stefan Roese | f31909c | 2007-02-07 09:45:55 +0100 | [diff] [blame] | 108 | /* clear status before enabling watchdog */ |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 109 | __booke_wdt_ping(NULL); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 110 | val = mfspr(SPRN_TCR); |
Matthias Fuchs | 0a0e9e0 | 2008-11-05 21:53:56 +0100 | [diff] [blame] | 111 | val &= ~WDTP_MASK; |
Kumar Gala | 39cdc4b | 2005-09-03 15:55:39 -0700 | [diff] [blame] | 112 | val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period)); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 113 | |
| 114 | mtspr(SPRN_TCR, val); |
| 115 | } |
| 116 | |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 117 | static ssize_t booke_wdt_write(struct file *file, const char __user *buf, |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 118 | size_t count, loff_t *ppos) |
| 119 | { |
| 120 | booke_wdt_ping(); |
| 121 | return count; |
| 122 | } |
| 123 | |
| 124 | static struct watchdog_info ident = { |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 125 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, |
| 126 | .identity = "PowerPC Book-E Watchdog", |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 127 | }; |
| 128 | |
Alan Cox | 00e9c20 | 2008-05-19 14:06:36 +0100 | [diff] [blame] | 129 | static long booke_wdt_ioctl(struct file *file, |
| 130 | unsigned int cmd, unsigned long arg) |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 131 | { |
| 132 | u32 tmp = 0; |
Al Viro | 538bacf | 2005-12-15 09:18:20 +0000 | [diff] [blame] | 133 | u32 __user *p = (u32 __user *)arg; |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 134 | |
| 135 | switch (cmd) { |
| 136 | case WDIOC_GETSUPPORT: |
Chris Friesen | dcfb748 | 2009-08-12 12:02:46 -0600 | [diff] [blame] | 137 | if (copy_to_user((void *)arg, &ident, sizeof(ident))) |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 138 | return -EFAULT; |
| 139 | case WDIOC_GETSTATUS: |
Al Viro | 538bacf | 2005-12-15 09:18:20 +0000 | [diff] [blame] | 140 | return put_user(ident.options, p); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 141 | 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 Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 146 | 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 Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 155 | case WDIOC_KEEPALIVE: |
| 156 | booke_wdt_ping(); |
| 157 | return 0; |
| 158 | case WDIOC_SETTIMEOUT: |
Chris Friesen | dcfb748 | 2009-08-12 12:02:46 -0600 | [diff] [blame] | 159 | if (get_user(tmp, p)) |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 160 | return -EFAULT; |
Chris Friesen | dcfb748 | 2009-08-12 12:02:46 -0600 | [diff] [blame] | 161 | #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 Fuchs | 0a0e9e0 | 2008-11-05 21:53:56 +0100 | [diff] [blame] | 169 | mtspr(SPRN_TCR, (mfspr(SPRN_TCR) & ~WDTP_MASK) | |
Alan Cox | 00e9c20 | 2008-05-19 14:06:36 +0100 | [diff] [blame] | 170 | WDTP(booke_wdt_period)); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 171 | return 0; |
| 172 | case WDIOC_GETTIMEOUT: |
Al Viro | 538bacf | 2005-12-15 09:18:20 +0000 | [diff] [blame] | 173 | return put_user(booke_wdt_period, p); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 174 | default: |
Samuel Tardieu | 795b89d | 2006-09-09 17:34:31 +0200 | [diff] [blame] | 175 | return -ENOTTY; |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 176 | } |
| 177 | |
| 178 | return 0; |
| 179 | } |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 180 | |
| 181 | static int booke_wdt_open(struct inode *inode, struct file *file) |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 182 | { |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 183 | spin_lock(&booke_wdt_lock); |
Kumar Gala | 39cdc4b | 2005-09-03 15:55:39 -0700 | [diff] [blame] | 184 | if (booke_wdt_enabled == 0) { |
| 185 | booke_wdt_enabled = 1; |
Ingo Molnar | f6f88e9 | 2008-07-15 22:08:52 +0200 | [diff] [blame] | 186 | on_each_cpu(__booke_wdt_enable, NULL, 0); |
Alan Cox | 00e9c20 | 2008-05-19 14:06:36 +0100 | [diff] [blame] | 187 | printk(KERN_INFO |
| 188 | "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n", |
| 189 | booke_wdt_period); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 190 | } |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 191 | spin_unlock(&booke_wdt_lock); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 192 | |
Wim Van Sebroeck | ec9505a | 2007-07-20 20:41:37 +0000 | [diff] [blame] | 193 | return nonseekable_open(inode, file); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 194 | } |
| 195 | |
Arjan van de Ven | 62322d2 | 2006-07-03 00:24:21 -0700 | [diff] [blame] | 196 | static const struct file_operations booke_wdt_fops = { |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 197 | .owner = THIS_MODULE, |
| 198 | .llseek = no_llseek, |
| 199 | .write = booke_wdt_write, |
Alan Cox | 00e9c20 | 2008-05-19 14:06:36 +0100 | [diff] [blame] | 200 | .unlocked_ioctl = booke_wdt_ioctl, |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 201 | .open = booke_wdt_open, |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 202 | }; |
| 203 | |
| 204 | static struct miscdevice booke_wdt_miscdev = { |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 205 | .minor = WATCHDOG_MINOR, |
| 206 | .name = "watchdog", |
| 207 | .fops = &booke_wdt_fops, |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 208 | }; |
| 209 | |
| 210 | static void __exit booke_wdt_exit(void) |
| 211 | { |
| 212 | misc_deregister(&booke_wdt_miscdev); |
| 213 | } |
| 214 | |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 215 | static int __init booke_wdt_init(void) |
| 216 | { |
| 217 | int ret = 0; |
| 218 | |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 219 | printk(KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n"); |
Al Viro | a78719c | 2005-12-16 22:35:28 +0000 | [diff] [blame] | 220 | ident.firmware_version = cur_cpu_spec->pvr_value; |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 221 | |
| 222 | ret = misc_register(&booke_wdt_miscdev); |
| 223 | if (ret) { |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 224 | printk(KERN_CRIT "Cannot register miscdev on minor=%d: %d\n", |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 225 | WATCHDOG_MINOR, ret); |
| 226 | return ret; |
| 227 | } |
| 228 | |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 229 | spin_lock(&booke_wdt_lock); |
Kumar Gala | 39cdc4b | 2005-09-03 15:55:39 -0700 | [diff] [blame] | 230 | if (booke_wdt_enabled == 1) { |
Alan Cox | 00e9c20 | 2008-05-19 14:06:36 +0100 | [diff] [blame] | 231 | printk(KERN_INFO |
| 232 | "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n", |
| 233 | booke_wdt_period); |
Ingo Molnar | f6f88e9 | 2008-07-15 22:08:52 +0200 | [diff] [blame] | 234 | on_each_cpu(__booke_wdt_enable, NULL, 0); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 235 | } |
Chen Gong | f172ddc6 | 2008-04-29 16:42:05 +0800 | [diff] [blame] | 236 | spin_unlock(&booke_wdt_lock); |
Kumar Gala | a2f40cc | 2005-09-03 15:55:33 -0700 | [diff] [blame] | 237 | |
| 238 | return ret; |
| 239 | } |
| 240 | device_initcall(booke_wdt_init); |