Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Watchdog driver for SiByte SB1 SoCs |
| 3 | * |
Andrew Sharp | 5b73a41 | 2009-09-23 16:03:20 -0700 | [diff] [blame] | 4 | * Copyright (C) 2007 OnStor, Inc. * Andrew Sharp <andy.sharp@lsi.com> |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 5 | * |
| 6 | * This driver is intended to make the second of two hardware watchdogs |
| 7 | * on the Sibyte 12XX and 11XX SoCs available to the user. There are two |
| 8 | * such devices available on the SoC, but it seems that there isn't an |
| 9 | * enumeration class for watchdogs in Linux like there is for RTCs. |
| 10 | * The second is used rather than the first because it uses IRQ 1, |
| 11 | * thereby avoiding all that IRQ 0 problematic nonsense. |
| 12 | * |
| 13 | * I have not tried this driver on a 1480 processor; it might work |
| 14 | * just well enough to really screw things up. |
| 15 | * |
| 16 | * It is a simple timer, and there is an interrupt that is raised the |
| 17 | * first time the timer expires. The second time it expires, the chip |
| 18 | * is reset and there is no way to redirect that NMI. Which could |
| 19 | * be problematic in some cases where this chip is sitting on the HT |
| 20 | * bus and has just taken responsibility for providing a cache block. |
| 21 | * Since the reset can't be redirected to the external reset pin, it is |
| 22 | * possible that other HT connected processors might hang and not reset. |
| 23 | * For Linux, a soft reset would probably be even worse than a hard reset. |
| 24 | * There you have it. |
| 25 | * |
| 26 | * The timer takes 23 bits of a 64 bit register (?) as a count value, |
| 27 | * and decrements the count every microsecond, for a max value of |
| 28 | * 0x7fffff usec or about 8.3ish seconds. |
| 29 | * |
| 30 | * This watchdog borrows some user semantics from the softdog driver, |
| 31 | * in that if you close the fd, it leaves the watchdog running, unless |
| 32 | * you previously wrote a 'V' to the fd, in which case it disables |
| 33 | * the watchdog when you close the fd like some other drivers. |
| 34 | * |
| 35 | * Based on various other watchdog drivers, which are probably all |
| 36 | * loosely based on something Alan Cox wrote years ago. |
| 37 | * |
Alan Cox | 29fa058 | 2008-10-27 15:17:56 +0000 | [diff] [blame] | 38 | * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
| 39 | * All Rights Reserved. |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 40 | * |
| 41 | * This program is free software; you can redistribute it and/or |
| 42 | * modify it under the terms of the GNU General Public License |
| 43 | * version 1 or 2 as published by the Free Software Foundation. |
| 44 | * |
| 45 | */ |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 46 | |
| 47 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 48 | |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 49 | #include <linux/module.h> |
| 50 | #include <linux/io.h> |
| 51 | #include <linux/uaccess.h> |
| 52 | #include <linux/fs.h> |
| 53 | #include <linux/reboot.h> |
| 54 | #include <linux/miscdevice.h> |
| 55 | #include <linux/watchdog.h> |
| 56 | #include <linux/interrupt.h> |
| 57 | |
| 58 | #include <asm/sibyte/sb1250.h> |
| 59 | #include <asm/sibyte/sb1250_regs.h> |
| 60 | #include <asm/sibyte/sb1250_int.h> |
| 61 | #include <asm/sibyte/sb1250_scd.h> |
| 62 | |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 63 | static DEFINE_SPINLOCK(sbwd_lock); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 64 | |
| 65 | /* |
| 66 | * set the initial count value of a timer |
| 67 | * |
| 68 | * wdog is the iomem address of the cfg register |
| 69 | */ |
| 70 | void sbwdog_set(char __iomem *wdog, unsigned long t) |
| 71 | { |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 72 | spin_lock(&sbwd_lock); |
Guenter Roeck | 8691331 | 2010-04-19 08:37:11 -0700 | [diff] [blame] | 73 | __raw_writeb(0, wdog); |
| 74 | __raw_writeq(t & 0x7fffffUL, wdog - 0x10); |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 75 | spin_unlock(&sbwd_lock); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 76 | } |
| 77 | |
| 78 | /* |
| 79 | * cause the timer to [re]load it's initial count and start counting |
| 80 | * all over again |
| 81 | * |
| 82 | * wdog is the iomem address of the cfg register |
| 83 | */ |
| 84 | void sbwdog_pet(char __iomem *wdog) |
| 85 | { |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 86 | spin_lock(&sbwd_lock); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 87 | __raw_writeb(__raw_readb(wdog) | 1, wdog); |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 88 | spin_unlock(&sbwd_lock); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | static unsigned long sbwdog_gate; /* keeps it to one thread only */ |
| 92 | static char __iomem *kern_dog = (char __iomem *)(IO_BASE + (A_SCD_WDOG_CFG_0)); |
| 93 | static char __iomem *user_dog = (char __iomem *)(IO_BASE + (A_SCD_WDOG_CFG_1)); |
| 94 | static unsigned long timeout = 0x7fffffUL; /* useconds: 8.3ish secs. */ |
| 95 | static int expect_close; |
| 96 | |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 97 | static const struct watchdog_info ident = { |
| 98 | .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | |
Wim Van Sebroeck | e73a780 | 2009-05-11 18:33:00 +0000 | [diff] [blame] | 99 | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 100 | .identity = "SiByte Watchdog", |
| 101 | }; |
| 102 | |
| 103 | /* |
| 104 | * Allow only a single thread to walk the dog |
| 105 | */ |
| 106 | static int sbwdog_open(struct inode *inode, struct file *file) |
| 107 | { |
| 108 | nonseekable_open(inode, file); |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 109 | if (test_and_set_bit(0, &sbwdog_gate)) |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 110 | return -EBUSY; |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 111 | __module_get(THIS_MODULE); |
| 112 | |
| 113 | /* |
| 114 | * Activate the timer |
| 115 | */ |
| 116 | sbwdog_set(user_dog, timeout); |
| 117 | __raw_writeb(1, user_dog); |
| 118 | |
| 119 | return 0; |
| 120 | } |
| 121 | |
| 122 | /* |
| 123 | * Put the dog back in the kennel. |
| 124 | */ |
| 125 | static int sbwdog_release(struct inode *inode, struct file *file) |
| 126 | { |
| 127 | if (expect_close == 42) { |
| 128 | __raw_writeb(0, user_dog); |
| 129 | module_put(THIS_MODULE); |
| 130 | } else { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 131 | pr_crit("%s: Unexpected close, not stopping watchdog!\n", |
| 132 | ident.identity); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 133 | sbwdog_pet(user_dog); |
| 134 | } |
| 135 | clear_bit(0, &sbwdog_gate); |
| 136 | expect_close = 0; |
| 137 | |
| 138 | return 0; |
| 139 | } |
| 140 | |
| 141 | /* |
| 142 | * 42 - the answer |
| 143 | */ |
| 144 | static ssize_t sbwdog_write(struct file *file, const char __user *data, |
| 145 | size_t len, loff_t *ppos) |
| 146 | { |
| 147 | int i; |
| 148 | |
| 149 | if (len) { |
| 150 | /* |
| 151 | * restart the timer |
| 152 | */ |
| 153 | expect_close = 0; |
| 154 | |
| 155 | for (i = 0; i != len; i++) { |
| 156 | char c; |
| 157 | |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 158 | if (get_user(c, data + i)) |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 159 | return -EFAULT; |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 160 | if (c == 'V') |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 161 | expect_close = 42; |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 162 | } |
| 163 | sbwdog_pet(user_dog); |
| 164 | } |
| 165 | |
| 166 | return len; |
| 167 | } |
| 168 | |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 169 | static long sbwdog_ioctl(struct file *file, unsigned int cmd, |
| 170 | unsigned long arg) |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 171 | { |
| 172 | int ret = -ENOTTY; |
| 173 | unsigned long time; |
| 174 | void __user *argp = (void __user *)arg; |
| 175 | int __user *p = argp; |
| 176 | |
| 177 | switch (cmd) { |
| 178 | case WDIOC_GETSUPPORT: |
| 179 | ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
| 180 | break; |
| 181 | |
| 182 | case WDIOC_GETSTATUS: |
| 183 | case WDIOC_GETBOOTSTATUS: |
| 184 | ret = put_user(0, p); |
| 185 | break; |
| 186 | |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 187 | case WDIOC_KEEPALIVE: |
| 188 | sbwdog_pet(user_dog); |
| 189 | ret = 0; |
| 190 | break; |
| 191 | |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 192 | case WDIOC_SETTIMEOUT: |
| 193 | ret = get_user(time, p); |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 194 | if (ret) |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 195 | break; |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 196 | |
| 197 | time *= 1000000; |
| 198 | if (time > 0x7fffffUL) { |
| 199 | ret = -EINVAL; |
| 200 | break; |
| 201 | } |
| 202 | timeout = time; |
| 203 | sbwdog_set(user_dog, timeout); |
| 204 | sbwdog_pet(user_dog); |
| 205 | |
| 206 | case WDIOC_GETTIMEOUT: |
| 207 | /* |
| 208 | * get the remaining count from the ... count register |
| 209 | * which is 1*8 before the config register |
| 210 | */ |
Ralf Baechle | cd6cbde | 2013-06-19 10:57:33 +0200 | [diff] [blame] | 211 | ret = put_user((u32)__raw_readq(user_dog - 8) / 1000000, p); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 212 | break; |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 213 | } |
| 214 | return ret; |
| 215 | } |
| 216 | |
| 217 | /* |
| 218 | * Notifier for system down |
| 219 | */ |
Wim Van Sebroeck | 7944d3a | 2008-08-06 20:19:41 +0000 | [diff] [blame] | 220 | static int sbwdog_notify_sys(struct notifier_block *this, unsigned long code, |
| 221 | void *erf) |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 222 | { |
| 223 | if (code == SYS_DOWN || code == SYS_HALT) { |
| 224 | /* |
| 225 | * sit and sit |
| 226 | */ |
| 227 | __raw_writeb(0, user_dog); |
| 228 | __raw_writeb(0, kern_dog); |
| 229 | } |
| 230 | |
| 231 | return NOTIFY_DONE; |
| 232 | } |
| 233 | |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 234 | static const struct file_operations sbwdog_fops = { |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 235 | .owner = THIS_MODULE, |
| 236 | .llseek = no_llseek, |
| 237 | .write = sbwdog_write, |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 238 | .unlocked_ioctl = sbwdog_ioctl, |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 239 | .open = sbwdog_open, |
| 240 | .release = sbwdog_release, |
| 241 | }; |
| 242 | |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 243 | static struct miscdevice sbwdog_miscdev = { |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 244 | .minor = WATCHDOG_MINOR, |
| 245 | .name = "watchdog", |
| 246 | .fops = &sbwdog_fops, |
| 247 | }; |
| 248 | |
| 249 | static struct notifier_block sbwdog_notifier = { |
| 250 | .notifier_call = sbwdog_notify_sys, |
| 251 | }; |
| 252 | |
| 253 | /* |
| 254 | * interrupt handler |
| 255 | * |
| 256 | * doesn't do a whole lot for user, but oh so cleverly written so kernel |
| 257 | * code can use it to re-up the watchdog, thereby saving the kernel from |
| 258 | * having to create and maintain a timer, just to tickle another timer, |
| 259 | * which is just so wrong. |
| 260 | */ |
| 261 | irqreturn_t sbwdog_interrupt(int irq, void *addr) |
| 262 | { |
| 263 | unsigned long wd_init; |
| 264 | char *wd_cfg_reg = (char *)addr; |
| 265 | u8 cfg; |
| 266 | |
| 267 | cfg = __raw_readb(wd_cfg_reg); |
| 268 | wd_init = __raw_readq(wd_cfg_reg - 8) & 0x7fffff; |
| 269 | |
| 270 | /* |
| 271 | * if it's the second watchdog timer, it's for those users |
| 272 | */ |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 273 | if (wd_cfg_reg == user_dog) |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 274 | pr_crit("%s in danger of initiating system reset " |
Wim Van Sebroeck | a77dba7 | 2009-04-14 20:20:07 +0000 | [diff] [blame] | 275 | "in %ld.%01ld seconds\n", |
| 276 | ident.identity, |
| 277 | wd_init / 1000000, (wd_init / 100000) % 10); |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 278 | else |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 279 | cfg |= 1; |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 280 | |
| 281 | __raw_writeb(cfg, wd_cfg_reg); |
| 282 | |
| 283 | return IRQ_HANDLED; |
| 284 | } |
| 285 | |
| 286 | static int __init sbwdog_init(void) |
| 287 | { |
| 288 | int ret; |
| 289 | |
| 290 | /* |
| 291 | * register a reboot notifier |
| 292 | */ |
| 293 | ret = register_reboot_notifier(&sbwdog_notifier); |
| 294 | if (ret) { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 295 | pr_err("%s: cannot register reboot notifier (err=%d)\n", |
| 296 | ident.identity, ret); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 297 | return ret; |
| 298 | } |
| 299 | |
| 300 | /* |
| 301 | * get the resources |
| 302 | */ |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 303 | |
Yong Zhang | 86b5912 | 2011-09-07 16:10:55 +0800 | [diff] [blame] | 304 | ret = request_irq(1, sbwdog_interrupt, IRQF_SHARED, |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 305 | ident.identity, (void *)user_dog); |
| 306 | if (ret) { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 307 | pr_err("%s: failed to request irq 1 - %d\n", |
| 308 | ident.identity, ret); |
Akinobu Mita | ae44855 | 2010-08-21 18:27:50 +0900 | [diff] [blame] | 309 | goto out; |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 310 | } |
| 311 | |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 312 | ret = misc_register(&sbwdog_miscdev); |
| 313 | if (ret == 0) { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 314 | pr_info("%s: timeout is %ld.%ld secs\n", |
| 315 | ident.identity, |
| 316 | timeout / 1000000, (timeout / 100000) % 10); |
Akinobu Mita | ae44855 | 2010-08-21 18:27:50 +0900 | [diff] [blame] | 317 | return 0; |
| 318 | } |
| 319 | free_irq(1, (void *)user_dog); |
| 320 | out: |
| 321 | unregister_reboot_notifier(&sbwdog_notifier); |
| 322 | |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 323 | return ret; |
| 324 | } |
| 325 | |
| 326 | static void __exit sbwdog_exit(void) |
| 327 | { |
| 328 | misc_deregister(&sbwdog_miscdev); |
Akinobu Mita | ae44855 | 2010-08-21 18:27:50 +0900 | [diff] [blame] | 329 | free_irq(1, (void *)user_dog); |
| 330 | unregister_reboot_notifier(&sbwdog_notifier); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 331 | } |
| 332 | |
| 333 | module_init(sbwdog_init); |
| 334 | module_exit(sbwdog_exit); |
| 335 | |
Andrew Sharp | 5b73a41 | 2009-09-23 16:03:20 -0700 | [diff] [blame] | 336 | MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>"); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 337 | MODULE_DESCRIPTION("SiByte Watchdog"); |
| 338 | |
| 339 | module_param(timeout, ulong, 0); |
| 340 | MODULE_PARM_DESC(timeout, |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 341 | "Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs)"); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 342 | |
| 343 | MODULE_LICENSE("GPL"); |
| 344 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| 345 | |
| 346 | /* |
| 347 | * example code that can be put in a platform code area to utilize the |
| 348 | * first watchdog timer for the kernels own purpose. |
| 349 | |
Alan Cox | df3c9de | 2008-05-19 14:08:33 +0100 | [diff] [blame] | 350 | void platform_wd_setup(void) |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 351 | { |
| 352 | int ret; |
| 353 | |
Yong Zhang | 86b5912 | 2011-09-07 16:10:55 +0800 | [diff] [blame] | 354 | ret = request_irq(1, sbwdog_interrupt, IRQF_SHARED, |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 355 | "Kernel Watchdog", IOADDR(A_SCD_WDOG_CFG_0)); |
| 356 | if (ret) { |
Joe Perches | 27c766a | 2012-02-15 15:06:19 -0800 | [diff] [blame] | 357 | pr_crit("Watchdog IRQ zero(0) failed to be requested - %d\n", ret); |
Andrew Sharp | 75c752e | 2007-12-13 16:16:42 -0800 | [diff] [blame] | 358 | } |
| 359 | } |
| 360 | |
| 361 | |
| 362 | */ |