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26#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
27
28#include <linux/module.h>
29#include <linux/moduleparam.h>
30#include <linux/errno.h>
31#include <linux/init.h>
32#include <linux/miscdevice.h>
33#include <linux/platform_device.h>
34#include <linux/watchdog.h>
35#include <linux/fs.h>
36#include <linux/ioport.h>
37#include <linux/io.h>
38#include <linux/uaccess.h>
39#include <linux/clk.h>
40
41#include <asm/addrspace.h>
42#include <asm/mach-ar7/ar7.h>
43
44#define LONGNAME "TI AR7 Watchdog Timer"
45
46MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
47MODULE_DESCRIPTION(LONGNAME);
48MODULE_LICENSE("GPL");
49MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
50
51static int margin = 60;
52module_param(margin, int, 0);
53MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
54
55static bool nowayout = WATCHDOG_NOWAYOUT;
56module_param(nowayout, bool, 0);
57MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
58
59#define READ_REG(x) readl((void __iomem *)&(x))
60#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
61
62struct ar7_wdt {
63 u32 kick_lock;
64 u32 kick;
65 u32 change_lock;
66 u32 change;
67 u32 disable_lock;
68 u32 disable;
69 u32 prescale_lock;
70 u32 prescale;
71};
72
73static unsigned long wdt_is_open;
74static unsigned expect_close;
75static DEFINE_SPINLOCK(wdt_lock);
76
77
78#define prescale_value 0xffff
79
80
81static struct resource *ar7_regs_wdt;
82
83static struct ar7_wdt *ar7_wdt;
84
85static struct clk *vbus_clk;
86
87static void ar7_wdt_kick(u32 value)
88{
89 WRITE_REG(ar7_wdt->kick_lock, 0x5555);
90 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
91 WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
92 if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
93 WRITE_REG(ar7_wdt->kick, value);
94 return;
95 }
96 }
97 pr_err("failed to unlock WDT kick reg\n");
98}
99
100static void ar7_wdt_prescale(u32 value)
101{
102 WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
103 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
104 WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
105 if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
106 WRITE_REG(ar7_wdt->prescale, value);
107 return;
108 }
109 }
110 pr_err("failed to unlock WDT prescale reg\n");
111}
112
113static void ar7_wdt_change(u32 value)
114{
115 WRITE_REG(ar7_wdt->change_lock, 0x6666);
116 if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
117 WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
118 if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
119 WRITE_REG(ar7_wdt->change, value);
120 return;
121 }
122 }
123 pr_err("failed to unlock WDT change reg\n");
124}
125
126static void ar7_wdt_disable(u32 value)
127{
128 WRITE_REG(ar7_wdt->disable_lock, 0x7777);
129 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
130 WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
131 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
132 WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
133 if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
134 WRITE_REG(ar7_wdt->disable, value);
135 return;
136 }
137 }
138 }
139 pr_err("failed to unlock WDT disable reg\n");
140}
141
142static void ar7_wdt_update_margin(int new_margin)
143{
144 u32 change;
145 u32 vbus_rate;
146
147 vbus_rate = clk_get_rate(vbus_clk);
148 change = new_margin * (vbus_rate / prescale_value);
149 if (change < 1)
150 change = 1;
151 if (change > 0xffff)
152 change = 0xffff;
153 ar7_wdt_change(change);
154 margin = change * prescale_value / vbus_rate;
155 pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n",
156 margin, prescale_value, change, vbus_rate);
157}
158
159static void ar7_wdt_enable_wdt(void)
160{
161 pr_debug("enabling watchdog timer\n");
162 ar7_wdt_disable(1);
163 ar7_wdt_kick(1);
164}
165
166static void ar7_wdt_disable_wdt(void)
167{
168 pr_debug("disabling watchdog timer\n");
169 ar7_wdt_disable(0);
170}
171
172static int ar7_wdt_open(struct inode *inode, struct file *file)
173{
174
175 if (test_and_set_bit(0, &wdt_is_open))
176 return -EBUSY;
177 ar7_wdt_enable_wdt();
178 expect_close = 0;
179
180 return nonseekable_open(inode, file);
181}
182
183static int ar7_wdt_release(struct inode *inode, struct file *file)
184{
185 if (!expect_close)
186 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
187 else if (!nowayout)
188 ar7_wdt_disable_wdt();
189 clear_bit(0, &wdt_is_open);
190 return 0;
191}
192
193static ssize_t ar7_wdt_write(struct file *file, const char *data,
194 size_t len, loff_t *ppos)
195{
196
197 if (len) {
198 size_t i;
199
200 spin_lock(&wdt_lock);
201 ar7_wdt_kick(1);
202 spin_unlock(&wdt_lock);
203
204 expect_close = 0;
205 for (i = 0; i < len; ++i) {
206 char c;
207 if (get_user(c, data + i))
208 return -EFAULT;
209 if (c == 'V')
210 expect_close = 1;
211 }
212
213 }
214 return len;
215}
216
217static long ar7_wdt_ioctl(struct file *file,
218 unsigned int cmd, unsigned long arg)
219{
220 static const struct watchdog_info ident = {
221 .identity = LONGNAME,
222 .firmware_version = 1,
223 .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
224 WDIOF_MAGICCLOSE),
225 };
226 int new_margin;
227
228 switch (cmd) {
229 case WDIOC_GETSUPPORT:
230 if (copy_to_user((struct watchdog_info *)arg, &ident,
231 sizeof(ident)))
232 return -EFAULT;
233 return 0;
234 case WDIOC_GETSTATUS:
235 case WDIOC_GETBOOTSTATUS:
236 if (put_user(0, (int *)arg))
237 return -EFAULT;
238 return 0;
239 case WDIOC_KEEPALIVE:
240 ar7_wdt_kick(1);
241 return 0;
242 case WDIOC_SETTIMEOUT:
243 if (get_user(new_margin, (int *)arg))
244 return -EFAULT;
245 if (new_margin < 1)
246 return -EINVAL;
247
248 spin_lock(&wdt_lock);
249 ar7_wdt_update_margin(new_margin);
250 ar7_wdt_kick(1);
251 spin_unlock(&wdt_lock);
252
253 case WDIOC_GETTIMEOUT:
254 if (put_user(margin, (int *)arg))
255 return -EFAULT;
256 return 0;
257 default:
258 return -ENOTTY;
259 }
260}
261
262static const struct file_operations ar7_wdt_fops = {
263 .owner = THIS_MODULE,
264 .write = ar7_wdt_write,
265 .unlocked_ioctl = ar7_wdt_ioctl,
266 .open = ar7_wdt_open,
267 .release = ar7_wdt_release,
268 .llseek = no_llseek,
269};
270
271static struct miscdevice ar7_wdt_miscdev = {
272 .minor = WATCHDOG_MINOR,
273 .name = "watchdog",
274 .fops = &ar7_wdt_fops,
275};
276
277static int ar7_wdt_probe(struct platform_device *pdev)
278{
279 int rc;
280
281 ar7_regs_wdt =
282 platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
283 if (!ar7_regs_wdt) {
284 pr_err("could not get registers resource\n");
285 return -ENODEV;
286 }
287
288 ar7_wdt = devm_ioremap_resource(&pdev->dev, ar7_regs_wdt);
289 if (IS_ERR(ar7_wdt))
290 return PTR_ERR(ar7_wdt);
291
292 vbus_clk = clk_get(NULL, "vbus");
293 if (IS_ERR(vbus_clk)) {
294 pr_err("could not get vbus clock\n");
295 return PTR_ERR(vbus_clk);
296 }
297
298 ar7_wdt_disable_wdt();
299 ar7_wdt_prescale(prescale_value);
300 ar7_wdt_update_margin(margin);
301
302 rc = misc_register(&ar7_wdt_miscdev);
303 if (rc) {
304 pr_err("unable to register misc device\n");
305 goto out;
306 }
307 return 0;
308
309out:
310 clk_put(vbus_clk);
311 vbus_clk = NULL;
312 return rc;
313}
314
315static int ar7_wdt_remove(struct platform_device *pdev)
316{
317 misc_deregister(&ar7_wdt_miscdev);
318 clk_put(vbus_clk);
319 vbus_clk = NULL;
320 return 0;
321}
322
323static void ar7_wdt_shutdown(struct platform_device *pdev)
324{
325 if (!nowayout)
326 ar7_wdt_disable_wdt();
327}
328
329static struct platform_driver ar7_wdt_driver = {
330 .probe = ar7_wdt_probe,
331 .remove = ar7_wdt_remove,
332 .shutdown = ar7_wdt_shutdown,
333 .driver = {
334 .owner = THIS_MODULE,
335 .name = "ar7_wdt",
336 },
337};
338
339module_platform_driver(ar7_wdt_driver);
340
