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2f58b8d0 JC |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify it | |
3 | * under the terms of the GNU General Public License version 2 as published | |
4 | * by the Free Software Foundation. | |
5 | * | |
6 | * Copyright (C) 2010 John Crispin <blogic@openwrt.org> | |
7 | * Based on EP93xx wdt driver | |
8 | */ | |
9 | ||
10 | #include <linux/module.h> | |
11 | #include <linux/fs.h> | |
12 | #include <linux/miscdevice.h> | |
13 | #include <linux/watchdog.h> | |
14 | #include <linux/platform_device.h> | |
15 | #include <linux/uaccess.h> | |
16 | #include <linux/clk.h> | |
17 | #include <linux/io.h> | |
18 | ||
19 | #include <lantiq.h> | |
20 | ||
21 | /* Section 3.4 of the datasheet | |
22 | * The password sequence protects the WDT control register from unintended | |
23 | * write actions, which might cause malfunction of the WDT. | |
24 | * | |
25 | * essentially the following two magic passwords need to be written to allow | |
26 | * IO access to the WDT core | |
27 | */ | |
28 | #define LTQ_WDT_PW1 0x00BE0000 | |
29 | #define LTQ_WDT_PW2 0x00DC0000 | |
30 | ||
31 | #define LTQ_WDT_CR 0x0 /* watchdog control register */ | |
32 | #define LTQ_WDT_SR 0x8 /* watchdog status register */ | |
33 | ||
34 | #define LTQ_WDT_SR_EN (0x1 << 31) /* enable bit */ | |
35 | #define LTQ_WDT_SR_PWD (0x3 << 26) /* turn on power */ | |
36 | #define LTQ_WDT_SR_CLKDIV (0x3 << 24) /* turn on clock and set */ | |
37 | /* divider to 0x40000 */ | |
38 | #define LTQ_WDT_DIVIDER 0x40000 | |
39 | #define LTQ_MAX_TIMEOUT ((1 << 16) - 1) /* the reload field is 16 bit */ | |
40 | ||
41 | static int nowayout = WATCHDOG_NOWAYOUT; | |
42 | ||
43 | static void __iomem *ltq_wdt_membase; | |
44 | static unsigned long ltq_io_region_clk_rate; | |
45 | ||
46 | static unsigned long ltq_wdt_bootstatus; | |
47 | static unsigned long ltq_wdt_in_use; | |
48 | static int ltq_wdt_timeout = 30; | |
49 | static int ltq_wdt_ok_to_close; | |
50 | ||
51 | static void | |
52 | ltq_wdt_enable(void) | |
53 | { | |
54 | ltq_wdt_timeout = ltq_wdt_timeout * | |
55 | (ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000; | |
56 | if (ltq_wdt_timeout > LTQ_MAX_TIMEOUT) | |
57 | ltq_wdt_timeout = LTQ_MAX_TIMEOUT; | |
58 | ||
59 | /* write the first password magic */ | |
60 | ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR); | |
61 | /* write the second magic plus the configuration and new timeout */ | |
62 | ltq_w32(LTQ_WDT_SR_EN | LTQ_WDT_SR_PWD | LTQ_WDT_SR_CLKDIV | | |
63 | LTQ_WDT_PW2 | ltq_wdt_timeout, ltq_wdt_membase + LTQ_WDT_CR); | |
64 | } | |
65 | ||
66 | static void | |
67 | ltq_wdt_disable(void) | |
68 | { | |
69 | /* write the first password magic */ | |
70 | ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR); | |
71 | /* write the second password magic with no config | |
72 | * this turns the watchdog off | |
73 | */ | |
74 | ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR); | |
75 | } | |
76 | ||
77 | static ssize_t | |
78 | ltq_wdt_write(struct file *file, const char __user *data, | |
79 | size_t len, loff_t *ppos) | |
80 | { | |
81 | if (len) { | |
82 | if (!nowayout) { | |
83 | size_t i; | |
84 | ||
85 | ltq_wdt_ok_to_close = 0; | |
86 | for (i = 0; i != len; i++) { | |
87 | char c; | |
88 | ||
89 | if (get_user(c, data + i)) | |
90 | return -EFAULT; | |
91 | if (c == 'V') | |
92 | ltq_wdt_ok_to_close = 1; | |
93 | else | |
94 | ltq_wdt_ok_to_close = 0; | |
95 | } | |
96 | } | |
97 | ltq_wdt_enable(); | |
98 | } | |
99 | ||
100 | return len; | |
101 | } | |
102 | ||
103 | static struct watchdog_info ident = { | |
104 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
105 | WDIOF_CARDRESET, | |
106 | .identity = "ltq_wdt", | |
107 | }; | |
108 | ||
109 | static long | |
110 | ltq_wdt_ioctl(struct file *file, | |
111 | unsigned int cmd, unsigned long arg) | |
112 | { | |
113 | int ret = -ENOTTY; | |
114 | ||
115 | switch (cmd) { | |
116 | case WDIOC_GETSUPPORT: | |
117 | ret = copy_to_user((struct watchdog_info __user *)arg, &ident, | |
118 | sizeof(ident)) ? -EFAULT : 0; | |
119 | break; | |
120 | ||
121 | case WDIOC_GETBOOTSTATUS: | |
122 | ret = put_user(ltq_wdt_bootstatus, (int __user *)arg); | |
123 | break; | |
124 | ||
125 | case WDIOC_GETSTATUS: | |
126 | ret = put_user(0, (int __user *)arg); | |
127 | break; | |
128 | ||
129 | case WDIOC_SETTIMEOUT: | |
130 | ret = get_user(ltq_wdt_timeout, (int __user *)arg); | |
131 | if (!ret) | |
132 | ltq_wdt_enable(); | |
133 | /* intentional drop through */ | |
134 | case WDIOC_GETTIMEOUT: | |
135 | ret = put_user(ltq_wdt_timeout, (int __user *)arg); | |
136 | break; | |
137 | ||
138 | case WDIOC_KEEPALIVE: | |
139 | ltq_wdt_enable(); | |
140 | ret = 0; | |
141 | break; | |
142 | } | |
143 | return ret; | |
144 | } | |
145 | ||
146 | static int | |
147 | ltq_wdt_open(struct inode *inode, struct file *file) | |
148 | { | |
149 | if (test_and_set_bit(0, <q_wdt_in_use)) | |
150 | return -EBUSY; | |
151 | ltq_wdt_in_use = 1; | |
152 | ltq_wdt_enable(); | |
153 | ||
154 | return nonseekable_open(inode, file); | |
155 | } | |
156 | ||
157 | static int | |
158 | ltq_wdt_release(struct inode *inode, struct file *file) | |
159 | { | |
160 | if (ltq_wdt_ok_to_close) | |
161 | ltq_wdt_disable(); | |
162 | else | |
163 | pr_err("ltq_wdt: watchdog closed without warning\n"); | |
164 | ltq_wdt_ok_to_close = 0; | |
165 | clear_bit(0, <q_wdt_in_use); | |
166 | ||
167 | return 0; | |
168 | } | |
169 | ||
170 | static const struct file_operations ltq_wdt_fops = { | |
171 | .owner = THIS_MODULE, | |
172 | .write = ltq_wdt_write, | |
173 | .unlocked_ioctl = ltq_wdt_ioctl, | |
174 | .open = ltq_wdt_open, | |
175 | .release = ltq_wdt_release, | |
176 | .llseek = no_llseek, | |
177 | }; | |
178 | ||
179 | static struct miscdevice ltq_wdt_miscdev = { | |
180 | .minor = WATCHDOG_MINOR, | |
181 | .name = "watchdog", | |
182 | .fops = <q_wdt_fops, | |
183 | }; | |
184 | ||
185 | static int __init | |
186 | ltq_wdt_probe(struct platform_device *pdev) | |
187 | { | |
188 | struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
189 | struct clk *clk; | |
190 | ||
191 | if (!res) { | |
192 | dev_err(&pdev->dev, "cannot obtain I/O memory region"); | |
193 | return -ENOENT; | |
194 | } | |
195 | res = devm_request_mem_region(&pdev->dev, res->start, | |
196 | resource_size(res), dev_name(&pdev->dev)); | |
197 | if (!res) { | |
198 | dev_err(&pdev->dev, "cannot request I/O memory region"); | |
199 | return -EBUSY; | |
200 | } | |
201 | ltq_wdt_membase = devm_ioremap_nocache(&pdev->dev, res->start, | |
202 | resource_size(res)); | |
203 | if (!ltq_wdt_membase) { | |
204 | dev_err(&pdev->dev, "cannot remap I/O memory region\n"); | |
205 | return -ENOMEM; | |
206 | } | |
207 | ||
208 | /* we do not need to enable the clock as it is always running */ | |
209 | clk = clk_get(&pdev->dev, "io"); | |
210 | WARN_ON(!clk); | |
211 | ltq_io_region_clk_rate = clk_get_rate(clk); | |
212 | clk_put(clk); | |
213 | ||
214 | if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST) | |
215 | ltq_wdt_bootstatus = WDIOF_CARDRESET; | |
216 | ||
217 | return misc_register(<q_wdt_miscdev); | |
218 | } | |
219 | ||
220 | static int __devexit | |
221 | ltq_wdt_remove(struct platform_device *pdev) | |
222 | { | |
223 | misc_deregister(<q_wdt_miscdev); | |
224 | ||
225 | if (ltq_wdt_membase) | |
226 | iounmap(ltq_wdt_membase); | |
227 | ||
228 | return 0; | |
229 | } | |
230 | ||
231 | ||
232 | static struct platform_driver ltq_wdt_driver = { | |
233 | .remove = __devexit_p(ltq_wdt_remove), | |
234 | .driver = { | |
235 | .name = "ltq_wdt", | |
236 | .owner = THIS_MODULE, | |
237 | }, | |
238 | }; | |
239 | ||
240 | static int __init | |
241 | init_ltq_wdt(void) | |
242 | { | |
243 | return platform_driver_probe(<q_wdt_driver, ltq_wdt_probe); | |
244 | } | |
245 | ||
246 | static void __exit | |
247 | exit_ltq_wdt(void) | |
248 | { | |
249 | return platform_driver_unregister(<q_wdt_driver); | |
250 | } | |
251 | ||
252 | module_init(init_ltq_wdt); | |
253 | module_exit(exit_ltq_wdt); | |
254 | ||
255 | module_param(nowayout, int, 0); | |
256 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); | |
257 | ||
258 | MODULE_AUTHOR("John Crispin <blogic@openwrt.org>"); | |
259 | MODULE_DESCRIPTION("Lantiq SoC Watchdog"); | |
260 | MODULE_LICENSE("GPL"); | |
261 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |