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10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/types.h>
13#include <linux/miscdevice.h>
14#include <linux/watchdog.h>
15#include <linux/fs.h>
16#include <linux/reboot.h>
17#include <linux/init.h>
18#include <linux/uaccess.h>
19#include <linux/platform_device.h>
20#include <linux/clk.h>
21#include <linux/err.h>
22#include <linux/io.h>
23#include <asm/txx9tmr.h>
24
25#define TIMER_MARGIN 60
26
27static int timeout = TIMER_MARGIN;
28module_param(timeout, int, 0);
29MODULE_PARM_DESC(timeout,
30 "Watchdog timeout in seconds. "
31 "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
32 "default=" __MODULE_STRING(TIMER_MARGIN) ")");
33
34static int nowayout = WATCHDOG_NOWAYOUT;
35module_param(nowayout, int, 0);
36MODULE_PARM_DESC(nowayout,
37 "Watchdog cannot be stopped once started "
38 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
39
40#define WD_TIMER_CCD 7
41#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
42#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
43
44static unsigned long txx9wdt_alive;
45static int expect_close;
46static struct txx9_tmr_reg __iomem *txx9wdt_reg;
47static struct clk *txx9_imclk;
48static DEFINE_SPINLOCK(txx9_lock);
49
50static void txx9wdt_ping(void)
51{
52 spin_lock(&txx9_lock);
53 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
54 spin_unlock(&txx9_lock);
55}
56
57static void txx9wdt_start(void)
58{
59 spin_lock(&txx9_lock);
60 __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
61 __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
62 __raw_writel(0, &txx9wdt_reg->tisr);
63 __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
64 &txx9wdt_reg->tcr);
65 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
66 spin_unlock(&txx9_lock);
67}
68
69static void txx9wdt_stop(void)
70{
71 spin_lock(&txx9_lock);
72 __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
73 __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
74 &txx9wdt_reg->tcr);
75 spin_unlock(&txx9_lock);
76}
77
78static int txx9wdt_open(struct inode *inode, struct file *file)
79{
80 if (test_and_set_bit(0, &txx9wdt_alive))
81 return -EBUSY;
82
83 if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
84 clear_bit(0, &txx9wdt_alive);
85 return -EBUSY;
86 }
87
88 if (nowayout)
89 __module_get(THIS_MODULE);
90
91 txx9wdt_start();
92 return nonseekable_open(inode, file);
93}
94
95static int txx9wdt_release(struct inode *inode, struct file *file)
96{
97 if (expect_close)
98 txx9wdt_stop();
99 else {
100 printk(KERN_CRIT "txx9wdt: "
101 "Unexpected close, not stopping watchdog!\n");
102 txx9wdt_ping();
103 }
104 clear_bit(0, &txx9wdt_alive);
105 expect_close = 0;
106 return 0;
107}
108
109static ssize_t txx9wdt_write(struct file *file, const char __user *data,
110 size_t len, loff_t *ppos)
111{
112 if (len) {
113 if (!nowayout) {
114 size_t i;
115
116 expect_close = 0;
117 for (i = 0; i != len; i++) {
118 char c;
119 if (get_user(c, data + i))
120 return -EFAULT;
121 if (c == 'V')
122 expect_close = 1;
123 }
124 }
125 txx9wdt_ping();
126 }
127 return len;
128}
129
130static long txx9wdt_ioctl(struct file *file, unsigned int cmd,
131 unsigned long arg)
132{
133 void __user *argp = (void __user *)arg;
134 int __user *p = argp;
135 int new_timeout;
136 static const struct watchdog_info ident = {
137 .options = WDIOF_SETTIMEOUT |
138 WDIOF_KEEPALIVEPING |
139 WDIOF_MAGICCLOSE,
140 .firmware_version = 0,
141 .identity = "Hardware Watchdog for TXx9",
142 };
143
144 switch (cmd) {
145 case WDIOC_GETSUPPORT:
146 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
147 case WDIOC_GETSTATUS:
148 case WDIOC_GETBOOTSTATUS:
149 return put_user(0, p);
150 case WDIOC_KEEPALIVE:
151 txx9wdt_ping();
152 return 0;
153 case WDIOC_SETTIMEOUT:
154 if (get_user(new_timeout, p))
155 return -EFAULT;
156 if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT)
157 return -EINVAL;
158 timeout = new_timeout;
159 txx9wdt_stop();
160 txx9wdt_start();
161
162 case WDIOC_GETTIMEOUT:
163 return put_user(timeout, p);
164 default:
165 return -ENOTTY;
166 }
167}
168
169static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code,
170 void *unused)
171{
172 if (code == SYS_DOWN || code == SYS_HALT)
173 txx9wdt_stop();
174 return NOTIFY_DONE;
175}
176
177static const struct file_operations txx9wdt_fops = {
178 .owner = THIS_MODULE,
179 .llseek = no_llseek,
180 .write = txx9wdt_write,
181 .unlocked_ioctl = txx9wdt_ioctl,
182 .open = txx9wdt_open,
183 .release = txx9wdt_release,
184};
185
186static struct miscdevice txx9wdt_miscdev = {
187 .minor = WATCHDOG_MINOR,
188 .name = "watchdog",
189 .fops = &txx9wdt_fops,
190};
191
192static struct notifier_block txx9wdt_notifier = {
193 .notifier_call = txx9wdt_notify_sys,
194};
195
196static int __init txx9wdt_probe(struct platform_device *dev)
197{
198 struct resource *res;
199 int ret;
200
201 txx9_imclk = clk_get(NULL, "imbus_clk");
202 if (IS_ERR(txx9_imclk)) {
203 ret = PTR_ERR(txx9_imclk);
204 txx9_imclk = NULL;
205 goto exit;
206 }
207 ret = clk_enable(txx9_imclk);
208 if (ret) {
209 clk_put(txx9_imclk);
210 txx9_imclk = NULL;
211 goto exit;
212 }
213
214 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
215 if (!res)
216 goto exit_busy;
217 if (!devm_request_mem_region(&dev->dev,
218 res->start, res->end - res->start + 1,
219 "txx9wdt"))
220 goto exit_busy;
221 txx9wdt_reg = devm_ioremap(&dev->dev,
222 res->start, res->end - res->start + 1);
223 if (!txx9wdt_reg)
224 goto exit_busy;
225
226 ret = register_reboot_notifier(&txx9wdt_notifier);
227 if (ret)
228 goto exit;
229
230 ret = misc_register(&txx9wdt_miscdev);
231 if (ret) {
232 unregister_reboot_notifier(&txx9wdt_notifier);
233 goto exit;
234 }
235
236 printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
237 "timeout=%d sec (max %ld) (nowayout= %d)\n",
238 timeout, WD_MAX_TIMEOUT, nowayout);
239
240 return 0;
241exit_busy:
242 ret = -EBUSY;
243exit:
244 if (txx9_imclk) {
245 clk_disable(txx9_imclk);
246 clk_put(txx9_imclk);
247 }
248 return ret;
249}
250
251static int __exit txx9wdt_remove(struct platform_device *dev)
252{
253 misc_deregister(&txx9wdt_miscdev);
254 unregister_reboot_notifier(&txx9wdt_notifier);
255 clk_disable(txx9_imclk);
256 clk_put(txx9_imclk);
257 return 0;
258}
259
260static struct platform_driver txx9wdt_driver = {
261 .remove = __exit_p(txx9wdt_remove),
262 .driver = {
263 .name = "txx9wdt",
264 .owner = THIS_MODULE,
265 },
266};
267
268static int __init watchdog_init(void)
269{
270 return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
271}
272
273static void __exit watchdog_exit(void)
274{
275 platform_driver_unregister(&txx9wdt_driver);
276}
277
278module_init(watchdog_init);
279module_exit(watchdog_exit);
280
281MODULE_DESCRIPTION("TXx9 Watchdog Driver");
282MODULE_LICENSE("GPL");
283MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
284MODULE_ALIAS("platform:txx9wdt");
285
