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15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
17#include <linux/module.h>
18#include <linux/moduleparam.h>
19#include <linux/types.h>
20#include <linux/errno.h>
21#include <linux/kernel.h>
22#include <linux/fs.h>
23#include <linux/miscdevice.h>
24#include <linux/watchdog.h>
25#include <linux/init.h>
26#include <linux/platform_device.h>
27#include <linux/spinlock.h>
28#include <linux/uaccess.h>
29#include <linux/io.h>
30
31#include <asm/mach-rc32434/integ.h>
32
33#define VERSION "1.0"
34
35static struct {
36 unsigned long inuse;
37 spinlock_t io_lock;
38} rc32434_wdt_device;
39
40static struct integ __iomem *wdt_reg;
41
42static int expect_close;
43
44
45
46extern unsigned int idt_cpu_freq;
47
48
49#define WTCOMP2SEC(x) (x / idt_cpu_freq)
50#define SEC2WTCOMP(x) (x * idt_cpu_freq)
51
52
53
54
55#define WATCHDOG_TIMEOUT 20
56
57static int timeout = WATCHDOG_TIMEOUT;
58module_param(timeout, int, 0);
59MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default="
60 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
61
62static bool nowayout = WATCHDOG_NOWAYOUT;
63module_param(nowayout, bool, 0);
64MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
65 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
66
67
68#define SET_BITS(addr, or, nand) \
69 writel((readl(&addr) | or) & ~nand, &addr)
70
71static int rc32434_wdt_set(int new_timeout)
72{
73 int max_to = WTCOMP2SEC((u32)-1);
74
75 if (new_timeout < 0 || new_timeout > max_to) {
76 pr_err("timeout value must be between 0 and %d\n", max_to);
77 return -EINVAL;
78 }
79 timeout = new_timeout;
80 spin_lock(&rc32434_wdt_device.io_lock);
81 writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare);
82 spin_unlock(&rc32434_wdt_device.io_lock);
83
84 return 0;
85}
86
87static void rc32434_wdt_start(void)
88{
89 u32 or, nand;
90
91 spin_lock(&rc32434_wdt_device.io_lock);
92
93
94 writel(0, &wdt_reg->wtcount);
95
96
97
98 nand = 1 << RC32434_ERR_WNE;
99 or = 1 << RC32434_ERR_WRE;
100
101
102 nand |= 1 << RC32434_ERR_WTO;
103
104 SET_BITS(wdt_reg->errcs, or, nand);
105
106
107 rc32434_wdt_set(timeout);
108
109
110 nand = 1 << RC32434_WTC_TO;
111 or = 1 << RC32434_WTC_EN;
112
113 SET_BITS(wdt_reg->wtc, or, nand);
114
115 spin_unlock(&rc32434_wdt_device.io_lock);
116 pr_info("Started watchdog timer\n");
117}
118
119static void rc32434_wdt_stop(void)
120{
121 spin_lock(&rc32434_wdt_device.io_lock);
122
123
124 SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN);
125
126 spin_unlock(&rc32434_wdt_device.io_lock);
127 pr_info("Stopped watchdog timer\n");
128}
129
130static void rc32434_wdt_ping(void)
131{
132 spin_lock(&rc32434_wdt_device.io_lock);
133 writel(0, &wdt_reg->wtcount);
134 spin_unlock(&rc32434_wdt_device.io_lock);
135}
136
137static int rc32434_wdt_open(struct inode *inode, struct file *file)
138{
139 if (test_and_set_bit(0, &rc32434_wdt_device.inuse))
140 return -EBUSY;
141
142 if (nowayout)
143 __module_get(THIS_MODULE);
144
145 rc32434_wdt_start();
146 rc32434_wdt_ping();
147
148 return stream_open(inode, file);
149}
150
151static int rc32434_wdt_release(struct inode *inode, struct file *file)
152{
153 if (expect_close == 42) {
154 rc32434_wdt_stop();
155 module_put(THIS_MODULE);
156 } else {
157 pr_crit("device closed unexpectedly. WDT will not stop!\n");
158 rc32434_wdt_ping();
159 }
160 clear_bit(0, &rc32434_wdt_device.inuse);
161 return 0;
162}
163
164static ssize_t rc32434_wdt_write(struct file *file, const char *data,
165 size_t len, loff_t *ppos)
166{
167 if (len) {
168 if (!nowayout) {
169 size_t i;
170
171
172 expect_close = 0;
173
174 for (i = 0; i != len; i++) {
175 char c;
176 if (get_user(c, data + i))
177 return -EFAULT;
178 if (c == 'V')
179 expect_close = 42;
180 }
181 }
182 rc32434_wdt_ping();
183 return len;
184 }
185 return 0;
186}
187
188static long rc32434_wdt_ioctl(struct file *file, unsigned int cmd,
189 unsigned long arg)
190{
191 void __user *argp = (void __user *)arg;
192 int new_timeout;
193 unsigned int value;
194 static const struct watchdog_info ident = {
195 .options = WDIOF_SETTIMEOUT |
196 WDIOF_KEEPALIVEPING |
197 WDIOF_MAGICCLOSE,
198 .identity = "RC32434_WDT Watchdog",
199 };
200 switch (cmd) {
201 case WDIOC_GETSUPPORT:
202 if (copy_to_user(argp, &ident, sizeof(ident)))
203 return -EFAULT;
204 break;
205 case WDIOC_GETSTATUS:
206 case WDIOC_GETBOOTSTATUS:
207 value = 0;
208 if (copy_to_user(argp, &value, sizeof(int)))
209 return -EFAULT;
210 break;
211 case WDIOC_SETOPTIONS:
212 if (copy_from_user(&value, argp, sizeof(int)))
213 return -EFAULT;
214 switch (value) {
215 case WDIOS_ENABLECARD:
216 rc32434_wdt_start();
217 break;
218 case WDIOS_DISABLECARD:
219 rc32434_wdt_stop();
220 break;
221 default:
222 return -EINVAL;
223 }
224 break;
225 case WDIOC_KEEPALIVE:
226 rc32434_wdt_ping();
227 break;
228 case WDIOC_SETTIMEOUT:
229 if (copy_from_user(&new_timeout, argp, sizeof(int)))
230 return -EFAULT;
231 if (rc32434_wdt_set(new_timeout))
232 return -EINVAL;
233
234 case WDIOC_GETTIMEOUT:
235 return copy_to_user(argp, &timeout, sizeof(int)) ? -EFAULT : 0;
236 default:
237 return -ENOTTY;
238 }
239
240 return 0;
241}
242
243static const struct file_operations rc32434_wdt_fops = {
244 .owner = THIS_MODULE,
245 .llseek = no_llseek,
246 .write = rc32434_wdt_write,
247 .unlocked_ioctl = rc32434_wdt_ioctl,
248 .open = rc32434_wdt_open,
249 .release = rc32434_wdt_release,
250};
251
252static struct miscdevice rc32434_wdt_miscdev = {
253 .minor = WATCHDOG_MINOR,
254 .name = "watchdog",
255 .fops = &rc32434_wdt_fops,
256};
257
258static int rc32434_wdt_probe(struct platform_device *pdev)
259{
260 int ret;
261 struct resource *r;
262
263 r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res");
264 if (!r) {
265 pr_err("failed to retrieve resources\n");
266 return -ENODEV;
267 }
268
269 wdt_reg = devm_ioremap_nocache(&pdev->dev, r->start, resource_size(r));
270 if (!wdt_reg) {
271 pr_err("failed to remap I/O resources\n");
272 return -ENXIO;
273 }
274
275 spin_lock_init(&rc32434_wdt_device.io_lock);
276
277
278 rc32434_wdt_stop();
279
280
281
282 if (rc32434_wdt_set(timeout)) {
283 rc32434_wdt_set(WATCHDOG_TIMEOUT);
284 pr_info("timeout value must be between 0 and %d\n",
285 WTCOMP2SEC((u32)-1));
286 }
287
288 ret = misc_register(&rc32434_wdt_miscdev);
289 if (ret < 0) {
290 pr_err("failed to register watchdog device\n");
291 return ret;
292 }
293
294 pr_info("Watchdog Timer version " VERSION ", timer margin: %d sec\n",
295 timeout);
296
297 return 0;
298}
299
300static int rc32434_wdt_remove(struct platform_device *pdev)
301{
302 misc_deregister(&rc32434_wdt_miscdev);
303 return 0;
304}
305
306static void rc32434_wdt_shutdown(struct platform_device *pdev)
307{
308 rc32434_wdt_stop();
309}
310
311static struct platform_driver rc32434_wdt_driver = {
312 .probe = rc32434_wdt_probe,
313 .remove = rc32434_wdt_remove,
314 .shutdown = rc32434_wdt_shutdown,
315 .driver = {
316 .name = "rc32434_wdt",
317 }
318};
319
320module_platform_driver(rc32434_wdt_driver);
321
322MODULE_AUTHOR("Ondrej Zajicek <santiago@crfreenet.org>,"
323 "Florian Fainelli <florian@openwrt.org>");
324MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog");
325MODULE_LICENSE("GPL");
326