aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/watchdog
diff options
context:
space:
mode:
authorAndrew Sharp <andy.sharp@onstor.com>2007-12-13 19:16:42 -0500
committerWim Van Sebroeck <wim@iguana.be>2008-02-18 11:53:47 -0500
commit75c752e6c3147f596c13365b200b91d754b66f59 (patch)
tree7f8d6ad758b24ffe5633755b8322727353feaeae /drivers/watchdog
parent1309d4e68497184d2fd87e892ddf14076c2bda98 (diff)
[WATCHDOG] Add support for SB1 hardware watchdog
Support watchdog timers built into SiByte MIPS SoCs. Signed-off-by: Andy Sharp <andy.sharp@onstor.com> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'drivers/watchdog')
-rw-r--r--drivers/watchdog/Kconfig13
-rw-r--r--drivers/watchdog/Makefile1
-rw-r--r--drivers/watchdog/sb_wdog.c353
3 files changed, 367 insertions, 0 deletions
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index afcdc69e37d6..591e3f399114 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -633,6 +633,19 @@ config WDT_RM9K_GPI
633 To compile this driver as a module, choose M here: the 633 To compile this driver as a module, choose M here: the
634 module will be called rm9k_wdt. 634 module will be called rm9k_wdt.
635 635
636config SIBYTE_WDOG
637 tristate "Sibyte SoC hardware watchdog"
638 depends on CPU_SB1
639 help
640 Watchdog driver for the built in watchdog hardware in Sibyte
641 SoC processors. There are apparently two watchdog timers
642 on such processors; this driver supports only the first one,
643 because currently Linux only supports exporting one watchdog
644 to userspace.
645
646 To compile this driver as a loadable module, choose M here.
647 The module will be called sb_wdog.
648
636config AR7_WDT 649config AR7_WDT
637 tristate "TI AR7 Watchdog Timer" 650 tristate "TI AR7 Watchdog Timer"
638 depends on AR7 651 depends on AR7
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index ebc21146d40c..90e4bbffbbfd 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -92,6 +92,7 @@ obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc_epx_c3.o
92obj-$(CONFIG_INDYDOG) += indydog.o 92obj-$(CONFIG_INDYDOG) += indydog.o
93obj-$(CONFIG_WDT_MTX1) += mtx-1_wdt.o 93obj-$(CONFIG_WDT_MTX1) += mtx-1_wdt.o
94obj-$(CONFIG_WDT_RM9K_GPI) += rm9k_wdt.o 94obj-$(CONFIG_WDT_RM9K_GPI) += rm9k_wdt.o
95obj-$(CONFIG_SIBYTE_WDOG) += sb_wdog.o
95obj-$(CONFIG_AR7_WDT) += ar7_wdt.o 96obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
96obj-$(CONFIG_TXX9_WDT) += txx9wdt.o 97obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
97 98
diff --git a/drivers/watchdog/sb_wdog.c b/drivers/watchdog/sb_wdog.c
new file mode 100644
index 000000000000..b94431433695
--- /dev/null
+++ b/drivers/watchdog/sb_wdog.c
@@ -0,0 +1,353 @@
1/*
2 * Watchdog driver for SiByte SB1 SoCs
3 *
4 * Copyright (C) 2007 OnStor, Inc. * Andrew Sharp <andy.sharp@onstor.com>
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 *
38 * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
39 * http://www.redhat.com
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 */
46#include <linux/module.h>
47#include <linux/io.h>
48#include <linux/uaccess.h>
49#include <linux/fs.h>
50#include <linux/reboot.h>
51#include <linux/miscdevice.h>
52#include <linux/watchdog.h>
53#include <linux/interrupt.h>
54
55#include <asm/sibyte/sb1250.h>
56#include <asm/sibyte/sb1250_regs.h>
57#include <asm/sibyte/sb1250_int.h>
58#include <asm/sibyte/sb1250_scd.h>
59
60
61/*
62 * set the initial count value of a timer
63 *
64 * wdog is the iomem address of the cfg register
65 */
66void sbwdog_set(char __iomem *wdog, unsigned long t)
67{
68 __raw_writeb(0, wdog - 0x10);
69 __raw_writeq(t & 0x7fffffUL, wdog);
70}
71
72/*
73 * cause the timer to [re]load it's initial count and start counting
74 * all over again
75 *
76 * wdog is the iomem address of the cfg register
77 */
78void sbwdog_pet(char __iomem *wdog)
79{
80 __raw_writeb(__raw_readb(wdog) | 1, wdog);
81}
82
83static unsigned long sbwdog_gate; /* keeps it to one thread only */
84static char __iomem *kern_dog = (char __iomem *)(IO_BASE + (A_SCD_WDOG_CFG_0));
85static char __iomem *user_dog = (char __iomem *)(IO_BASE + (A_SCD_WDOG_CFG_1));
86static unsigned long timeout = 0x7fffffUL; /* useconds: 8.3ish secs. */
87static int expect_close;
88
89static struct watchdog_info ident = {
90 .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
91 .identity = "SiByte Watchdog",
92};
93
94/*
95 * Allow only a single thread to walk the dog
96 */
97static int sbwdog_open(struct inode *inode, struct file *file)
98{
99 nonseekable_open(inode, file);
100 if (test_and_set_bit(0, &sbwdog_gate)) {
101 return -EBUSY;
102 }
103 __module_get(THIS_MODULE);
104
105 /*
106 * Activate the timer
107 */
108 sbwdog_set(user_dog, timeout);
109 __raw_writeb(1, user_dog);
110
111 return 0;
112}
113
114/*
115 * Put the dog back in the kennel.
116 */
117static int sbwdog_release(struct inode *inode, struct file *file)
118{
119 if (expect_close == 42) {
120 __raw_writeb(0, user_dog);
121 module_put(THIS_MODULE);
122 } else {
123 printk(KERN_CRIT "%s: Unexpected close, not stopping watchdog!\n",
124 ident.identity);
125 sbwdog_pet(user_dog);
126 }
127 clear_bit(0, &sbwdog_gate);
128 expect_close = 0;
129
130 return 0;
131}
132
133/*
134 * 42 - the answer
135 */
136static ssize_t sbwdog_write(struct file *file, const char __user *data,
137 size_t len, loff_t *ppos)
138{
139 int i;
140
141 if (len) {
142 /*
143 * restart the timer
144 */
145 expect_close = 0;
146
147 for (i = 0; i != len; i++) {
148 char c;
149
150 if (get_user(c, data + i)) {
151 return -EFAULT;
152 }
153 if (c == 'V') {
154 expect_close = 42;
155 }
156 }
157 sbwdog_pet(user_dog);
158 }
159
160 return len;
161}
162
163static int sbwdog_ioctl(struct inode *inode, struct file *file,
164 unsigned int cmd, unsigned long arg)
165{
166 int ret = -ENOTTY;
167 unsigned long time;
168 void __user *argp = (void __user *)arg;
169 int __user *p = argp;
170
171 switch (cmd) {
172 case WDIOC_GETSUPPORT:
173 ret = copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
174 break;
175
176 case WDIOC_GETSTATUS:
177 case WDIOC_GETBOOTSTATUS:
178 ret = put_user(0, p);
179 break;
180
181 case WDIOC_SETTIMEOUT:
182 ret = get_user(time, p);
183 if (ret) {
184 break;
185 }
186
187 time *= 1000000;
188 if (time > 0x7fffffUL) {
189 ret = -EINVAL;
190 break;
191 }
192 timeout = time;
193 sbwdog_set(user_dog, timeout);
194 sbwdog_pet(user_dog);
195
196 case WDIOC_GETTIMEOUT:
197 /*
198 * get the remaining count from the ... count register
199 * which is 1*8 before the config register
200 */
201 ret = put_user(__raw_readq(user_dog - 8) / 1000000, p);
202 break;
203
204 case WDIOC_KEEPALIVE:
205 sbwdog_pet(user_dog);
206 ret = 0;
207 break;
208 }
209 return ret;
210}
211
212/*
213 * Notifier for system down
214 */
215static int
216sbwdog_notify_sys(struct notifier_block *this, unsigned long code, void *erf)
217{
218 if (code == SYS_DOWN || code == SYS_HALT) {
219 /*
220 * sit and sit
221 */
222 __raw_writeb(0, user_dog);
223 __raw_writeb(0, kern_dog);
224 }
225
226 return NOTIFY_DONE;
227}
228
229static const struct file_operations sbwdog_fops =
230{
231 .owner = THIS_MODULE,
232 .llseek = no_llseek,
233 .write = sbwdog_write,
234 .ioctl = sbwdog_ioctl,
235 .open = sbwdog_open,
236 .release = sbwdog_release,
237};
238
239static struct miscdevice sbwdog_miscdev =
240{
241 .minor = WATCHDOG_MINOR,
242 .name = "watchdog",
243 .fops = &sbwdog_fops,
244};
245
246static struct notifier_block sbwdog_notifier = {
247 .notifier_call = sbwdog_notify_sys,
248};
249
250/*
251 * interrupt handler
252 *
253 * doesn't do a whole lot for user, but oh so cleverly written so kernel
254 * code can use it to re-up the watchdog, thereby saving the kernel from
255 * having to create and maintain a timer, just to tickle another timer,
256 * which is just so wrong.
257 */
258irqreturn_t sbwdog_interrupt(int irq, void *addr)
259{
260 unsigned long wd_init;
261 char *wd_cfg_reg = (char *)addr;
262 u8 cfg;
263
264 cfg = __raw_readb(wd_cfg_reg);
265 wd_init = __raw_readq(wd_cfg_reg - 8) & 0x7fffff;
266
267 /*
268 * if it's the second watchdog timer, it's for those users
269 */
270 if (wd_cfg_reg == user_dog) {
271 printk(KERN_CRIT
272 "%s in danger of initiating system reset in %ld.%01ld seconds\n",
273 ident.identity, wd_init / 1000000, (wd_init / 100000) % 10);
274 } else {
275 cfg |= 1;
276 }
277
278 __raw_writeb(cfg, wd_cfg_reg);
279
280 return IRQ_HANDLED;
281}
282
283static int __init sbwdog_init(void)
284{
285 int ret;
286
287 /*
288 * register a reboot notifier
289 */
290 ret = register_reboot_notifier(&sbwdog_notifier);
291 if (ret) {
292 printk (KERN_ERR "%s: cannot register reboot notifier (err=%d)\n",
293 ident.identity, ret);
294 return ret;
295 }
296
297 /*
298 * get the resources
299 */
300 ret = misc_register(&sbwdog_miscdev);
301 if (ret == 0) {
302 printk(KERN_INFO "%s: timeout is %ld.%ld secs\n", ident.identity,
303 timeout / 1000000, (timeout / 100000) % 10);
304 }
305
306 ret = request_irq(1, sbwdog_interrupt, IRQF_DISABLED | IRQF_SHARED,
307 ident.identity, (void *)user_dog);
308 if (ret) {
309 printk(KERN_ERR "%s: failed to request irq 1 - %d\n", ident.identity,
310 ret);
311 misc_deregister(&sbwdog_miscdev);
312 }
313
314 return ret;
315}
316
317static void __exit sbwdog_exit(void)
318{
319 misc_deregister(&sbwdog_miscdev);
320}
321
322module_init(sbwdog_init);
323module_exit(sbwdog_exit);
324
325MODULE_AUTHOR("Andrew Sharp <andy.sharp@onstor.com>");
326MODULE_DESCRIPTION("SiByte Watchdog");
327
328module_param(timeout, ulong, 0);
329MODULE_PARM_DESC(timeout,
330 "Watchdog timeout in microseconds (max/default 8388607 or 8.3ish secs)");
331
332MODULE_LICENSE("GPL");
333MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
334
335/*
336 * example code that can be put in a platform code area to utilize the
337 * first watchdog timer for the kernels own purpose.
338
339 void
340platform_wd_setup(void)
341{
342 int ret;
343
344 ret = request_irq(0, sbwdog_interrupt, IRQF_DISABLED | IRQF_SHARED,
345 "Kernel Watchdog", IOADDR(A_SCD_WDOG_CFG_0));
346 if (ret) {
347 printk(KERN_CRIT "Watchdog IRQ zero(0) failed to be requested - %d\n",
348 ret);
349 }
350}
351
352
353 */