Root/drivers/watchdog/rdc321x_wdt.c

1/*
2 * RDC321x watchdog driver
3 *
4 * Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
5 *
6 * This driver is highly inspired from the cpu5_wdt driver
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 *
22 */
23
24#include <linux/module.h>
25#include <linux/moduleparam.h>
26#include <linux/types.h>
27#include <linux/errno.h>
28#include <linux/miscdevice.h>
29#include <linux/fs.h>
30#include <linux/init.h>
31#include <linux/ioport.h>
32#include <linux/timer.h>
33#include <linux/completion.h>
34#include <linux/jiffies.h>
35#include <linux/platform_device.h>
36#include <linux/watchdog.h>
37#include <linux/io.h>
38#include <linux/uaccess.h>
39#include <linux/mfd/rdc321x.h>
40
41#define RDC_WDT_MASK 0x80000000 /* Mask */
42#define RDC_WDT_EN 0x00800000 /* Enable bit */
43#define RDC_WDT_WTI 0x00200000 /* Generate CPU reset/NMI/WDT on timeout */
44#define RDC_WDT_RST 0x00100000 /* Reset bit */
45#define RDC_WDT_WIF 0x00040000 /* WDT IRQ Flag */
46#define RDC_WDT_IRT 0x00000100 /* IRQ Routing table */
47#define RDC_WDT_CNT 0x00000001 /* WDT count */
48
49#define RDC_CLS_TMR 0x80003844 /* Clear timer */
50
51#define RDC_WDT_INTERVAL (HZ/10+1)
52
53static int ticks = 1000;
54
55/* some device data */
56
57static struct {
58    struct completion stop;
59    int running;
60    struct timer_list timer;
61    int queue;
62    int default_ticks;
63    unsigned long inuse;
64    spinlock_t lock;
65    struct pci_dev *sb_pdev;
66    int base_reg;
67} rdc321x_wdt_device;
68
69/* generic helper functions */
70
71static void rdc321x_wdt_trigger(unsigned long unused)
72{
73    unsigned long flags;
74    u32 val;
75
76    if (rdc321x_wdt_device.running)
77        ticks--;
78
79    /* keep watchdog alive */
80    spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
81    pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
82                    rdc321x_wdt_device.base_reg, &val);
83    val |= RDC_WDT_EN;
84    pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
85                    rdc321x_wdt_device.base_reg, val);
86    spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
87
88    /* requeue?? */
89    if (rdc321x_wdt_device.queue && ticks)
90        mod_timer(&rdc321x_wdt_device.timer,
91                jiffies + RDC_WDT_INTERVAL);
92    else {
93        /* ticks doesn't matter anyway */
94        complete(&rdc321x_wdt_device.stop);
95    }
96
97}
98
99static void rdc321x_wdt_reset(void)
100{
101    ticks = rdc321x_wdt_device.default_ticks;
102}
103
104static void rdc321x_wdt_start(void)
105{
106    unsigned long flags;
107
108    if (!rdc321x_wdt_device.queue) {
109        rdc321x_wdt_device.queue = 1;
110
111        /* Clear the timer */
112        spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
113        pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
114                rdc321x_wdt_device.base_reg, RDC_CLS_TMR);
115
116        /* Enable watchdog and set the timeout to 81.92 us */
117        pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
118                    rdc321x_wdt_device.base_reg,
119                    RDC_WDT_EN | RDC_WDT_CNT);
120        spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
121
122        mod_timer(&rdc321x_wdt_device.timer,
123                jiffies + RDC_WDT_INTERVAL);
124    }
125
126    /* if process dies, counter is not decremented */
127    rdc321x_wdt_device.running++;
128}
129
130static int rdc321x_wdt_stop(void)
131{
132    if (rdc321x_wdt_device.running)
133        rdc321x_wdt_device.running = 0;
134
135    ticks = rdc321x_wdt_device.default_ticks;
136
137    return -EIO;
138}
139
140/* filesystem operations */
141static int rdc321x_wdt_open(struct inode *inode, struct file *file)
142{
143    if (test_and_set_bit(0, &rdc321x_wdt_device.inuse))
144        return -EBUSY;
145
146    return nonseekable_open(inode, file);
147}
148
149static int rdc321x_wdt_release(struct inode *inode, struct file *file)
150{
151    clear_bit(0, &rdc321x_wdt_device.inuse);
152    return 0;
153}
154
155static long rdc321x_wdt_ioctl(struct file *file, unsigned int cmd,
156                unsigned long arg)
157{
158    void __user *argp = (void __user *)arg;
159    u32 value;
160    static const struct watchdog_info ident = {
161        .options = WDIOF_CARDRESET,
162        .identity = "RDC321x WDT",
163    };
164    unsigned long flags;
165
166    switch (cmd) {
167    case WDIOC_KEEPALIVE:
168        rdc321x_wdt_reset();
169        break;
170    case WDIOC_GETSTATUS:
171        /* Read the value from the DATA register */
172        spin_lock_irqsave(&rdc321x_wdt_device.lock, flags);
173        pci_read_config_dword(rdc321x_wdt_device.sb_pdev,
174                    rdc321x_wdt_device.base_reg, &value);
175        spin_unlock_irqrestore(&rdc321x_wdt_device.lock, flags);
176        if (copy_to_user(argp, &value, sizeof(u32)))
177            return -EFAULT;
178        break;
179    case WDIOC_GETSUPPORT:
180        if (copy_to_user(argp, &ident, sizeof(ident)))
181            return -EFAULT;
182        break;
183    case WDIOC_SETOPTIONS:
184        if (copy_from_user(&value, argp, sizeof(int)))
185            return -EFAULT;
186        switch (value) {
187        case WDIOS_ENABLECARD:
188            rdc321x_wdt_start();
189            break;
190        case WDIOS_DISABLECARD:
191            return rdc321x_wdt_stop();
192        default:
193            return -EINVAL;
194        }
195        break;
196    default:
197        return -ENOTTY;
198    }
199    return 0;
200}
201
202static ssize_t rdc321x_wdt_write(struct file *file, const char __user *buf,
203                size_t count, loff_t *ppos)
204{
205    if (!count)
206        return -EIO;
207
208    rdc321x_wdt_reset();
209
210    return count;
211}
212
213static const struct file_operations rdc321x_wdt_fops = {
214    .owner = THIS_MODULE,
215    .llseek = no_llseek,
216    .unlocked_ioctl = rdc321x_wdt_ioctl,
217    .open = rdc321x_wdt_open,
218    .write = rdc321x_wdt_write,
219    .release = rdc321x_wdt_release,
220};
221
222static struct miscdevice rdc321x_wdt_misc = {
223    .minor = WATCHDOG_MINOR,
224    .name = "watchdog",
225    .fops = &rdc321x_wdt_fops,
226};
227
228static int __devinit rdc321x_wdt_probe(struct platform_device *pdev)
229{
230    int err;
231    struct resource *r;
232    struct rdc321x_wdt_pdata *pdata;
233
234    pdata = pdev->dev.platform_data;
235    if (!pdata) {
236        dev_err(&pdev->dev, "no platform data supplied\n");
237        return -ENODEV;
238    }
239
240    r = platform_get_resource_byname(pdev, IORESOURCE_IO, "wdt-reg");
241    if (!r) {
242        dev_err(&pdev->dev, "failed to get wdt-reg resource\n");
243        return -ENODEV;
244    }
245
246    rdc321x_wdt_device.sb_pdev = pdata->sb_pdev;
247    rdc321x_wdt_device.base_reg = r->start;
248
249    err = misc_register(&rdc321x_wdt_misc);
250    if (err < 0) {
251        dev_err(&pdev->dev, "misc_register failed\n");
252        return err;
253    }
254
255    spin_lock_init(&rdc321x_wdt_device.lock);
256
257    /* Reset the watchdog */
258    pci_write_config_dword(rdc321x_wdt_device.sb_pdev,
259                rdc321x_wdt_device.base_reg, RDC_WDT_RST);
260
261    init_completion(&rdc321x_wdt_device.stop);
262    rdc321x_wdt_device.queue = 0;
263
264    clear_bit(0, &rdc321x_wdt_device.inuse);
265
266    setup_timer(&rdc321x_wdt_device.timer, rdc321x_wdt_trigger, 0);
267
268    rdc321x_wdt_device.default_ticks = ticks;
269
270    dev_info(&pdev->dev, "watchdog init success\n");
271
272    return 0;
273}
274
275static int __devexit rdc321x_wdt_remove(struct platform_device *pdev)
276{
277    if (rdc321x_wdt_device.queue) {
278        rdc321x_wdt_device.queue = 0;
279        wait_for_completion(&rdc321x_wdt_device.stop);
280    }
281
282    misc_deregister(&rdc321x_wdt_misc);
283
284    return 0;
285}
286
287static struct platform_driver rdc321x_wdt_driver = {
288    .probe = rdc321x_wdt_probe,
289    .remove = __devexit_p(rdc321x_wdt_remove),
290    .driver = {
291        .owner = THIS_MODULE,
292        .name = "rdc321x-wdt",
293    },
294};
295
296module_platform_driver(rdc321x_wdt_driver);
297
298MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
299MODULE_DESCRIPTION("RDC321x watchdog driver");
300MODULE_LICENSE("GPL");
301MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
302

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