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70c14ff0 DW |
1 | /* |
2 | * drivers/char/watchdog/iop_wdt.c | |
3 | * | |
4 | * WDT driver for Intel I/O Processors | |
5 | * Copyright (C) 2005, Intel Corporation. | |
6 | * | |
7 | * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify it | |
10 | * under the terms and conditions of the GNU General Public License, | |
11 | * version 2, as published by the Free Software Foundation. | |
12 | * | |
13 | * This program is distributed in the hope it will be useful, but WITHOUT | |
14 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
16 | * more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License along with | |
19 | * this program; if not, write to the Free Software Foundation, Inc., 59 Temple | |
20 | * Place - Suite 330, Boston, MA 02111-1307 USA. | |
21 | * | |
22 | * Curt E Bruns <curt.e.bruns@intel.com> | |
23 | * Peter Milne <peter.milne@d-tacq.com> | |
24 | * Dan Williams <dan.j.williams@intel.com> | |
25 | */ | |
26 | ||
27 | #include <linux/module.h> | |
28 | #include <linux/kernel.h> | |
29 | #include <linux/fs.h> | |
30 | #include <linux/init.h> | |
31 | #include <linux/device.h> | |
32 | #include <linux/miscdevice.h> | |
33 | #include <linux/watchdog.h> | |
34 | #include <linux/uaccess.h> | |
a09e64fb | 35 | #include <mach/hardware.h> |
70c14ff0 DW |
36 | |
37 | static int nowayout = WATCHDOG_NOWAYOUT; | |
38 | static unsigned long wdt_status; | |
39 | static unsigned long boot_status; | |
1334f329 | 40 | static DEFINE_SPINLOCK(wdt_lock); |
70c14ff0 DW |
41 | |
42 | #define WDT_IN_USE 0 | |
43 | #define WDT_OK_TO_CLOSE 1 | |
44 | #define WDT_ENABLED 2 | |
45 | ||
46 | static unsigned long iop_watchdog_timeout(void) | |
47 | { | |
48 | return (0xffffffffUL / get_iop_tick_rate()); | |
49 | } | |
50 | ||
51 | /** | |
52 | * wdt_supports_disable - determine if we are accessing a iop13xx watchdog | |
53 | * or iop3xx by whether it has a disable command | |
54 | */ | |
55 | static int wdt_supports_disable(void) | |
56 | { | |
57 | int can_disable; | |
58 | ||
59 | if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM) | |
60 | can_disable = 1; | |
61 | else | |
62 | can_disable = 0; | |
63 | ||
64 | return can_disable; | |
65 | } | |
66 | ||
67 | static void wdt_enable(void) | |
68 | { | |
69 | /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF | |
70 | * Takes approx. 10.7s to timeout | |
71 | */ | |
02e3814e | 72 | spin_lock(&wdt_lock); |
70c14ff0 DW |
73 | write_wdtcr(IOP_WDTCR_EN_ARM); |
74 | write_wdtcr(IOP_WDTCR_EN); | |
02e3814e | 75 | spin_unlock(&wdt_lock); |
70c14ff0 DW |
76 | } |
77 | ||
78 | /* returns 0 if the timer was successfully disabled */ | |
79 | static int wdt_disable(void) | |
80 | { | |
81 | /* Stop Counting */ | |
82 | if (wdt_supports_disable()) { | |
02e3814e | 83 | spin_lock(&wdt_lock); |
70c14ff0 DW |
84 | write_wdtcr(IOP_WDTCR_DIS_ARM); |
85 | write_wdtcr(IOP_WDTCR_DIS); | |
86 | clear_bit(WDT_ENABLED, &wdt_status); | |
02e3814e | 87 | spin_unlock(&wdt_lock); |
70c14ff0 DW |
88 | printk(KERN_INFO "WATCHDOG: Disabled\n"); |
89 | return 0; | |
90 | } else | |
91 | return 1; | |
92 | } | |
93 | ||
94 | static int iop_wdt_open(struct inode *inode, struct file *file) | |
95 | { | |
96 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) | |
97 | return -EBUSY; | |
98 | ||
99 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
70c14ff0 | 100 | wdt_enable(); |
70c14ff0 | 101 | set_bit(WDT_ENABLED, &wdt_status); |
70c14ff0 DW |
102 | return nonseekable_open(inode, file); |
103 | } | |
104 | ||
02e3814e | 105 | static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len, |
70c14ff0 DW |
106 | loff_t *ppos) |
107 | { | |
108 | if (len) { | |
109 | if (!nowayout) { | |
110 | size_t i; | |
111 | ||
112 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
113 | ||
114 | for (i = 0; i != len; i++) { | |
115 | char c; | |
116 | ||
117 | if (get_user(c, data + i)) | |
118 | return -EFAULT; | |
119 | if (c == 'V') | |
120 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
121 | } | |
122 | } | |
123 | wdt_enable(); | |
124 | } | |
70c14ff0 DW |
125 | return len; |
126 | } | |
127 | ||
02e3814e | 128 | static const struct watchdog_info ident = { |
70c14ff0 DW |
129 | .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, |
130 | .identity = "iop watchdog", | |
131 | }; | |
132 | ||
02e3814e AC |
133 | static long iop_wdt_ioctl(struct file *file, |
134 | unsigned int cmd, unsigned long arg) | |
70c14ff0 DW |
135 | { |
136 | int options; | |
137 | int ret = -ENOTTY; | |
02e3814e | 138 | int __user *argp = (int __user *)arg; |
70c14ff0 DW |
139 | |
140 | switch (cmd) { | |
141 | case WDIOC_GETSUPPORT: | |
e04ab958 | 142 | if (copy_to_user(argp, &ident, sizeof(ident))) |
70c14ff0 DW |
143 | ret = -EFAULT; |
144 | else | |
145 | ret = 0; | |
146 | break; | |
147 | ||
148 | case WDIOC_GETSTATUS: | |
02e3814e | 149 | ret = put_user(0, argp); |
70c14ff0 DW |
150 | break; |
151 | ||
152 | case WDIOC_GETBOOTSTATUS: | |
02e3814e | 153 | ret = put_user(boot_status, argp); |
70c14ff0 DW |
154 | break; |
155 | ||
156 | case WDIOC_SETOPTIONS: | |
157 | if (get_user(options, (int *)arg)) | |
158 | return -EFAULT; | |
159 | ||
160 | if (options & WDIOS_DISABLECARD) { | |
161 | if (!nowayout) { | |
162 | if (wdt_disable() == 0) { | |
163 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
164 | ret = 0; | |
165 | } else | |
166 | ret = -ENXIO; | |
167 | } else | |
168 | ret = 0; | |
169 | } | |
70c14ff0 DW |
170 | if (options & WDIOS_ENABLECARD) { |
171 | wdt_enable(); | |
172 | ret = 0; | |
173 | } | |
174 | break; | |
70c14ff0 | 175 | |
0c06090c WVS |
176 | case WDIOC_KEEPALIVE: |
177 | wdt_enable(); | |
178 | ret = 0; | |
179 | break; | |
180 | ||
181 | case WDIOC_GETTIMEOUT: | |
182 | ret = put_user(iop_watchdog_timeout(), argp); | |
183 | break; | |
70c14ff0 | 184 | } |
70c14ff0 DW |
185 | return ret; |
186 | } | |
187 | ||
188 | static int iop_wdt_release(struct inode *inode, struct file *file) | |
189 | { | |
190 | int state = 1; | |
191 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) | |
192 | if (test_bit(WDT_ENABLED, &wdt_status)) | |
193 | state = wdt_disable(); | |
194 | ||
4b512d26 | 195 | /* if the timer is not disabled reload and notify that we are still |
70c14ff0 DW |
196 | * going down |
197 | */ | |
198 | if (state != 0) { | |
199 | wdt_enable(); | |
200 | printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " | |
201 | "reset in %lu seconds\n", iop_watchdog_timeout()); | |
202 | } | |
203 | ||
204 | clear_bit(WDT_IN_USE, &wdt_status); | |
205 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); | |
206 | ||
207 | return 0; | |
208 | } | |
209 | ||
210 | static const struct file_operations iop_wdt_fops = { | |
211 | .owner = THIS_MODULE, | |
212 | .llseek = no_llseek, | |
213 | .write = iop_wdt_write, | |
02e3814e | 214 | .unlocked_ioctl = iop_wdt_ioctl, |
70c14ff0 DW |
215 | .open = iop_wdt_open, |
216 | .release = iop_wdt_release, | |
217 | }; | |
218 | ||
219 | static struct miscdevice iop_wdt_miscdev = { | |
220 | .minor = WATCHDOG_MINOR, | |
221 | .name = "watchdog", | |
222 | .fops = &iop_wdt_fops, | |
223 | }; | |
224 | ||
225 | static int __init iop_wdt_init(void) | |
226 | { | |
227 | int ret; | |
228 | ||
70c14ff0 DW |
229 | /* check if the reset was caused by the watchdog timer */ |
230 | boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0; | |
231 | ||
232 | /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset | |
233 | * NOTE: An IB Reset will Reset both cores in the IOP342 | |
234 | */ | |
235 | write_wdtsr(IOP13XX_WDTCR_IB_RESET); | |
236 | ||
02e3814e AC |
237 | /* Register after we have the device set up so we cannot race |
238 | with an open */ | |
239 | ret = misc_register(&iop_wdt_miscdev); | |
240 | if (ret == 0) | |
7944d3a5 | 241 | printk(KERN_INFO "iop watchdog timer: timeout %lu sec\n", |
02e3814e AC |
242 | iop_watchdog_timeout()); |
243 | ||
70c14ff0 DW |
244 | return ret; |
245 | } | |
246 | ||
247 | static void __exit iop_wdt_exit(void) | |
248 | { | |
249 | misc_deregister(&iop_wdt_miscdev); | |
250 | } | |
251 | ||
252 | module_init(iop_wdt_init); | |
253 | module_exit(iop_wdt_exit); | |
254 | ||
255 | module_param(nowayout, int, 0); | |
256 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); | |
257 | ||
258 | MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>"); | |
259 | MODULE_DESCRIPTION("iop watchdog timer driver"); | |
260 | MODULE_LICENSE("GPL"); | |
261 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |