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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 | ||
27c766aa JP |
10 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
11 | ||
2f58b8d0 JC |
12 | #include <linux/module.h> |
13 | #include <linux/fs.h> | |
14 | #include <linux/miscdevice.h> | |
15 | #include <linux/watchdog.h> | |
16 | #include <linux/platform_device.h> | |
17 | #include <linux/uaccess.h> | |
18 | #include <linux/clk.h> | |
19 | #include <linux/io.h> | |
20 | ||
21 | #include <lantiq.h> | |
22 | ||
23 | /* Section 3.4 of the datasheet | |
24 | * The password sequence protects the WDT control register from unintended | |
25 | * write actions, which might cause malfunction of the WDT. | |
26 | * | |
27 | * essentially the following two magic passwords need to be written to allow | |
28 | * IO access to the WDT core | |
29 | */ | |
30 | #define LTQ_WDT_PW1 0x00BE0000 | |
31 | #define LTQ_WDT_PW2 0x00DC0000 | |
32 | ||
33 | #define LTQ_WDT_CR 0x0 /* watchdog control register */ | |
34 | #define LTQ_WDT_SR 0x8 /* watchdog status register */ | |
35 | ||
36 | #define LTQ_WDT_SR_EN (0x1 << 31) /* enable bit */ | |
37 | #define LTQ_WDT_SR_PWD (0x3 << 26) /* turn on power */ | |
38 | #define LTQ_WDT_SR_CLKDIV (0x3 << 24) /* turn on clock and set */ | |
39 | /* divider to 0x40000 */ | |
40 | #define LTQ_WDT_DIVIDER 0x40000 | |
41 | #define LTQ_MAX_TIMEOUT ((1 << 16) - 1) /* the reload field is 16 bit */ | |
42 | ||
86a1e189 | 43 | static bool nowayout = WATCHDOG_NOWAYOUT; |
2f58b8d0 JC |
44 | |
45 | static void __iomem *ltq_wdt_membase; | |
46 | static unsigned long ltq_io_region_clk_rate; | |
47 | ||
48 | static unsigned long ltq_wdt_bootstatus; | |
49 | static unsigned long ltq_wdt_in_use; | |
50 | static int ltq_wdt_timeout = 30; | |
51 | static int ltq_wdt_ok_to_close; | |
52 | ||
53 | static void | |
54 | ltq_wdt_enable(void) | |
55 | { | |
9cfce47b | 56 | unsigned long int timeout = ltq_wdt_timeout * |
2f58b8d0 | 57 | (ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000; |
9cfce47b JC |
58 | if (timeout > LTQ_MAX_TIMEOUT) |
59 | timeout = LTQ_MAX_TIMEOUT; | |
2f58b8d0 JC |
60 | |
61 | /* write the first password magic */ | |
62 | ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR); | |
63 | /* write the second magic plus the configuration and new timeout */ | |
64 | ltq_w32(LTQ_WDT_SR_EN | LTQ_WDT_SR_PWD | LTQ_WDT_SR_CLKDIV | | |
9cfce47b | 65 | LTQ_WDT_PW2 | timeout, ltq_wdt_membase + LTQ_WDT_CR); |
2f58b8d0 JC |
66 | } |
67 | ||
68 | static void | |
69 | ltq_wdt_disable(void) | |
70 | { | |
71 | /* write the first password magic */ | |
72 | ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR); | |
73 | /* write the second password magic with no config | |
74 | * this turns the watchdog off | |
75 | */ | |
76 | ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR); | |
77 | } | |
78 | ||
79 | static ssize_t | |
80 | ltq_wdt_write(struct file *file, const char __user *data, | |
81 | size_t len, loff_t *ppos) | |
82 | { | |
83 | if (len) { | |
84 | if (!nowayout) { | |
85 | size_t i; | |
86 | ||
87 | ltq_wdt_ok_to_close = 0; | |
88 | for (i = 0; i != len; i++) { | |
89 | char c; | |
90 | ||
91 | if (get_user(c, data + i)) | |
92 | return -EFAULT; | |
93 | if (c == 'V') | |
94 | ltq_wdt_ok_to_close = 1; | |
95 | else | |
96 | ltq_wdt_ok_to_close = 0; | |
97 | } | |
98 | } | |
99 | ltq_wdt_enable(); | |
100 | } | |
101 | ||
102 | return len; | |
103 | } | |
104 | ||
105 | static struct watchdog_info ident = { | |
106 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
107 | WDIOF_CARDRESET, | |
108 | .identity = "ltq_wdt", | |
109 | }; | |
110 | ||
111 | static long | |
112 | ltq_wdt_ioctl(struct file *file, | |
113 | unsigned int cmd, unsigned long arg) | |
114 | { | |
115 | int ret = -ENOTTY; | |
116 | ||
117 | switch (cmd) { | |
118 | case WDIOC_GETSUPPORT: | |
119 | ret = copy_to_user((struct watchdog_info __user *)arg, &ident, | |
120 | sizeof(ident)) ? -EFAULT : 0; | |
121 | break; | |
122 | ||
123 | case WDIOC_GETBOOTSTATUS: | |
124 | ret = put_user(ltq_wdt_bootstatus, (int __user *)arg); | |
125 | break; | |
126 | ||
127 | case WDIOC_GETSTATUS: | |
128 | ret = put_user(0, (int __user *)arg); | |
129 | break; | |
130 | ||
131 | case WDIOC_SETTIMEOUT: | |
132 | ret = get_user(ltq_wdt_timeout, (int __user *)arg); | |
133 | if (!ret) | |
134 | ltq_wdt_enable(); | |
135 | /* intentional drop through */ | |
136 | case WDIOC_GETTIMEOUT: | |
137 | ret = put_user(ltq_wdt_timeout, (int __user *)arg); | |
138 | break; | |
139 | ||
140 | case WDIOC_KEEPALIVE: | |
141 | ltq_wdt_enable(); | |
142 | ret = 0; | |
143 | break; | |
144 | } | |
145 | return ret; | |
146 | } | |
147 | ||
148 | static int | |
149 | ltq_wdt_open(struct inode *inode, struct file *file) | |
150 | { | |
151 | if (test_and_set_bit(0, <q_wdt_in_use)) | |
152 | return -EBUSY; | |
153 | ltq_wdt_in_use = 1; | |
154 | ltq_wdt_enable(); | |
155 | ||
156 | return nonseekable_open(inode, file); | |
157 | } | |
158 | ||
159 | static int | |
160 | ltq_wdt_release(struct inode *inode, struct file *file) | |
161 | { | |
162 | if (ltq_wdt_ok_to_close) | |
163 | ltq_wdt_disable(); | |
164 | else | |
27c766aa | 165 | pr_err("watchdog closed without warning\n"); |
2f58b8d0 JC |
166 | ltq_wdt_ok_to_close = 0; |
167 | clear_bit(0, <q_wdt_in_use); | |
168 | ||
169 | return 0; | |
170 | } | |
171 | ||
172 | static const struct file_operations ltq_wdt_fops = { | |
173 | .owner = THIS_MODULE, | |
174 | .write = ltq_wdt_write, | |
175 | .unlocked_ioctl = ltq_wdt_ioctl, | |
176 | .open = ltq_wdt_open, | |
177 | .release = ltq_wdt_release, | |
178 | .llseek = no_llseek, | |
179 | }; | |
180 | ||
181 | static struct miscdevice ltq_wdt_miscdev = { | |
182 | .minor = WATCHDOG_MINOR, | |
183 | .name = "watchdog", | |
184 | .fops = <q_wdt_fops, | |
185 | }; | |
186 | ||
187 | static int __init | |
188 | ltq_wdt_probe(struct platform_device *pdev) | |
189 | { | |
190 | struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
191 | struct clk *clk; | |
192 | ||
193 | if (!res) { | |
194 | dev_err(&pdev->dev, "cannot obtain I/O memory region"); | |
195 | return -ENOENT; | |
196 | } | |
197 | res = devm_request_mem_region(&pdev->dev, res->start, | |
198 | resource_size(res), dev_name(&pdev->dev)); | |
199 | if (!res) { | |
200 | dev_err(&pdev->dev, "cannot request I/O memory region"); | |
201 | return -EBUSY; | |
202 | } | |
203 | ltq_wdt_membase = devm_ioremap_nocache(&pdev->dev, res->start, | |
204 | resource_size(res)); | |
205 | if (!ltq_wdt_membase) { | |
206 | dev_err(&pdev->dev, "cannot remap I/O memory region\n"); | |
207 | return -ENOMEM; | |
208 | } | |
209 | ||
210 | /* we do not need to enable the clock as it is always running */ | |
211 | clk = clk_get(&pdev->dev, "io"); | |
212 | WARN_ON(!clk); | |
213 | ltq_io_region_clk_rate = clk_get_rate(clk); | |
214 | clk_put(clk); | |
215 | ||
216 | if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST) | |
217 | ltq_wdt_bootstatus = WDIOF_CARDRESET; | |
218 | ||
219 | return misc_register(<q_wdt_miscdev); | |
220 | } | |
221 | ||
222 | static int __devexit | |
223 | ltq_wdt_remove(struct platform_device *pdev) | |
224 | { | |
225 | misc_deregister(<q_wdt_miscdev); | |
226 | ||
2f58b8d0 JC |
227 | return 0; |
228 | } | |
229 | ||
230 | ||
231 | static struct platform_driver ltq_wdt_driver = { | |
232 | .remove = __devexit_p(ltq_wdt_remove), | |
233 | .driver = { | |
234 | .name = "ltq_wdt", | |
235 | .owner = THIS_MODULE, | |
236 | }, | |
237 | }; | |
238 | ||
239 | static int __init | |
240 | init_ltq_wdt(void) | |
241 | { | |
242 | return platform_driver_probe(<q_wdt_driver, ltq_wdt_probe); | |
243 | } | |
244 | ||
245 | static void __exit | |
246 | exit_ltq_wdt(void) | |
247 | { | |
248 | return platform_driver_unregister(<q_wdt_driver); | |
249 | } | |
250 | ||
251 | module_init(init_ltq_wdt); | |
252 | module_exit(exit_ltq_wdt); | |
253 | ||
86a1e189 | 254 | module_param(nowayout, bool, 0); |
2f58b8d0 JC |
255 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
256 | ||
257 | MODULE_AUTHOR("John Crispin <blogic@openwrt.org>"); | |
258 | MODULE_DESCRIPTION("Lantiq SoC Watchdog"); | |
259 | MODULE_LICENSE("GPL"); | |
260 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |