drm/i915: sync hdmi detection by hdmi identifier with 2D
[linux-2.6] / drivers / watchdog / txx9wdt.c
1 /*
2  * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
3  *
4  * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
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              /* Default is 60 seconds */
26
27 static int timeout = TIMER_MARGIN;      /* in seconds */
28 module_param(timeout, int, 0);
29 MODULE_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
34 static int nowayout = WATCHDOG_NOWAYOUT;
35 module_param(nowayout, int, 0);
36 MODULE_PARM_DESC(nowayout,
37         "Watchdog cannot be stopped once started "
38         "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
39
40 #define WD_TIMER_CCD    7       /* 1/256 */
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
44 static unsigned long txx9wdt_alive;
45 static int expect_close;
46 static struct txx9_tmr_reg __iomem *txx9wdt_reg;
47 static struct clk *txx9_imclk;
48 static DEFINE_SPINLOCK(txx9_lock);
49
50 static 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
57 static 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);    /* clear pending interrupt */
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
69 static 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
78 static 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
95 static 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
109 static 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
130 static 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                 /* Fall */
162         case WDIOC_GETTIMEOUT:
163                 return put_user(timeout, p);
164         default:
165                 return -ENOTTY;
166         }
167 }
168
169 static 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
177 static 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
186 static struct miscdevice txx9wdt_miscdev = {
187         .minor  =       WATCHDOG_MINOR,
188         .name   =       "watchdog",
189         .fops   =       &txx9wdt_fops,
190 };
191
192 static struct notifier_block txx9wdt_notifier = {
193         .notifier_call = txx9wdt_notify_sys,
194 };
195
196 static 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;
241 exit_busy:
242         ret = -EBUSY;
243 exit:
244         if (txx9_imclk) {
245                 clk_disable(txx9_imclk);
246                 clk_put(txx9_imclk);
247         }
248         return ret;
249 }
250
251 static 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
260 static struct platform_driver txx9wdt_driver = {
261         .remove = __exit_p(txx9wdt_remove),
262         .driver = {
263                 .name = "txx9wdt",
264                 .owner = THIS_MODULE,
265         },
266 };
267
268 static int __init watchdog_init(void)
269 {
270         return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
271 }
272
273 static void __exit watchdog_exit(void)
274 {
275         platform_driver_unregister(&txx9wdt_driver);
276 }
277
278 module_init(watchdog_init);
279 module_exit(watchdog_exit);
280
281 MODULE_DESCRIPTION("TXx9 Watchdog Driver");
282 MODULE_LICENSE("GPL");
283 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
284 MODULE_ALIAS("platform:txx9wdt");