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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> | |
cdb86121 | 16 | #include <linux/of_platform.h> |
2f58b8d0 JC |
17 | #include <linux/uaccess.h> |
18 | #include <linux/clk.h> | |
19 | #include <linux/io.h> | |
20 | ||
cdb86121 | 21 | #include <lantiq_soc.h> |
2f58b8d0 | 22 | |
cdb86121 JC |
23 | /* |
24 | * Section 3.4 of the datasheet | |
2f58b8d0 JC |
25 | * The password sequence protects the WDT control register from unintended |
26 | * write actions, which might cause malfunction of the WDT. | |
27 | * | |
28 | * essentially the following two magic passwords need to be written to allow | |
29 | * IO access to the WDT core | |
30 | */ | |
31 | #define LTQ_WDT_PW1 0x00BE0000 | |
32 | #define LTQ_WDT_PW2 0x00DC0000 | |
33 | ||
34 | #define LTQ_WDT_CR 0x0 /* watchdog control register */ | |
35 | #define LTQ_WDT_SR 0x8 /* watchdog status register */ | |
36 | ||
37 | #define LTQ_WDT_SR_EN (0x1 << 31) /* enable bit */ | |
38 | #define LTQ_WDT_SR_PWD (0x3 << 26) /* turn on power */ | |
39 | #define LTQ_WDT_SR_CLKDIV (0x3 << 24) /* turn on clock and set */ | |
40 | /* divider to 0x40000 */ | |
41 | #define LTQ_WDT_DIVIDER 0x40000 | |
42 | #define LTQ_MAX_TIMEOUT ((1 << 16) - 1) /* the reload field is 16 bit */ | |
43 | ||
86a1e189 | 44 | static bool nowayout = WATCHDOG_NOWAYOUT; |
2f58b8d0 JC |
45 | |
46 | static void __iomem *ltq_wdt_membase; | |
47 | static unsigned long ltq_io_region_clk_rate; | |
48 | ||
49 | static unsigned long ltq_wdt_bootstatus; | |
50 | static unsigned long ltq_wdt_in_use; | |
51 | static int ltq_wdt_timeout = 30; | |
52 | static int ltq_wdt_ok_to_close; | |
53 | ||
54 | static void | |
55 | ltq_wdt_enable(void) | |
56 | { | |
9cfce47b | 57 | unsigned long int timeout = ltq_wdt_timeout * |
2f58b8d0 | 58 | (ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000; |
9cfce47b JC |
59 | if (timeout > LTQ_MAX_TIMEOUT) |
60 | timeout = LTQ_MAX_TIMEOUT; | |
2f58b8d0 JC |
61 | |
62 | /* write the first password magic */ | |
63 | ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR); | |
64 | /* write the second magic plus the configuration and new timeout */ | |
65 | ltq_w32(LTQ_WDT_SR_EN | LTQ_WDT_SR_PWD | LTQ_WDT_SR_CLKDIV | | |
9cfce47b | 66 | LTQ_WDT_PW2 | timeout, ltq_wdt_membase + LTQ_WDT_CR); |
2f58b8d0 JC |
67 | } |
68 | ||
69 | static void | |
70 | ltq_wdt_disable(void) | |
71 | { | |
72 | /* write the first password magic */ | |
73 | ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR); | |
cdb86121 JC |
74 | /* |
75 | * write the second password magic with no config | |
2f58b8d0 JC |
76 | * this turns the watchdog off |
77 | */ | |
78 | ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR); | |
79 | } | |
80 | ||
81 | static ssize_t | |
82 | ltq_wdt_write(struct file *file, const char __user *data, | |
83 | size_t len, loff_t *ppos) | |
84 | { | |
85 | if (len) { | |
86 | if (!nowayout) { | |
87 | size_t i; | |
88 | ||
89 | ltq_wdt_ok_to_close = 0; | |
90 | for (i = 0; i != len; i++) { | |
91 | char c; | |
92 | ||
93 | if (get_user(c, data + i)) | |
94 | return -EFAULT; | |
95 | if (c == 'V') | |
96 | ltq_wdt_ok_to_close = 1; | |
97 | else | |
98 | ltq_wdt_ok_to_close = 0; | |
99 | } | |
100 | } | |
101 | ltq_wdt_enable(); | |
102 | } | |
103 | ||
104 | return len; | |
105 | } | |
106 | ||
107 | static struct watchdog_info ident = { | |
108 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | | |
109 | WDIOF_CARDRESET, | |
110 | .identity = "ltq_wdt", | |
111 | }; | |
112 | ||
113 | static long | |
114 | ltq_wdt_ioctl(struct file *file, | |
115 | unsigned int cmd, unsigned long arg) | |
116 | { | |
117 | int ret = -ENOTTY; | |
118 | ||
119 | switch (cmd) { | |
120 | case WDIOC_GETSUPPORT: | |
121 | ret = copy_to_user((struct watchdog_info __user *)arg, &ident, | |
122 | sizeof(ident)) ? -EFAULT : 0; | |
123 | break; | |
124 | ||
125 | case WDIOC_GETBOOTSTATUS: | |
126 | ret = put_user(ltq_wdt_bootstatus, (int __user *)arg); | |
127 | break; | |
128 | ||
129 | case WDIOC_GETSTATUS: | |
130 | ret = put_user(0, (int __user *)arg); | |
131 | break; | |
132 | ||
133 | case WDIOC_SETTIMEOUT: | |
134 | ret = get_user(ltq_wdt_timeout, (int __user *)arg); | |
135 | if (!ret) | |
136 | ltq_wdt_enable(); | |
137 | /* intentional drop through */ | |
138 | case WDIOC_GETTIMEOUT: | |
139 | ret = put_user(ltq_wdt_timeout, (int __user *)arg); | |
140 | break; | |
141 | ||
142 | case WDIOC_KEEPALIVE: | |
143 | ltq_wdt_enable(); | |
144 | ret = 0; | |
145 | break; | |
146 | } | |
147 | return ret; | |
148 | } | |
149 | ||
150 | static int | |
151 | ltq_wdt_open(struct inode *inode, struct file *file) | |
152 | { | |
153 | if (test_and_set_bit(0, <q_wdt_in_use)) | |
154 | return -EBUSY; | |
155 | ltq_wdt_in_use = 1; | |
156 | ltq_wdt_enable(); | |
157 | ||
158 | return nonseekable_open(inode, file); | |
159 | } | |
160 | ||
161 | static int | |
162 | ltq_wdt_release(struct inode *inode, struct file *file) | |
163 | { | |
164 | if (ltq_wdt_ok_to_close) | |
165 | ltq_wdt_disable(); | |
166 | else | |
27c766aa | 167 | pr_err("watchdog closed without warning\n"); |
2f58b8d0 JC |
168 | ltq_wdt_ok_to_close = 0; |
169 | clear_bit(0, <q_wdt_in_use); | |
170 | ||
171 | return 0; | |
172 | } | |
173 | ||
174 | static const struct file_operations ltq_wdt_fops = { | |
175 | .owner = THIS_MODULE, | |
176 | .write = ltq_wdt_write, | |
177 | .unlocked_ioctl = ltq_wdt_ioctl, | |
178 | .open = ltq_wdt_open, | |
179 | .release = ltq_wdt_release, | |
180 | .llseek = no_llseek, | |
181 | }; | |
182 | ||
183 | static struct miscdevice ltq_wdt_miscdev = { | |
184 | .minor = WATCHDOG_MINOR, | |
185 | .name = "watchdog", | |
186 | .fops = <q_wdt_fops, | |
187 | }; | |
188 | ||
2d991a16 | 189 | static int |
2f58b8d0 JC |
190 | ltq_wdt_probe(struct platform_device *pdev) |
191 | { | |
192 | struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
193 | struct clk *clk; | |
194 | ||
195 | if (!res) { | |
196 | dev_err(&pdev->dev, "cannot obtain I/O memory region"); | |
197 | return -ENOENT; | |
198 | } | |
cdb86121 | 199 | |
4c271bb6 TR |
200 | ltq_wdt_membase = devm_ioremap_resource(&pdev->dev, res); |
201 | if (IS_ERR(ltq_wdt_membase)) | |
202 | return PTR_ERR(ltq_wdt_membase); | |
2f58b8d0 JC |
203 | |
204 | /* we do not need to enable the clock as it is always running */ | |
cdb86121 JC |
205 | clk = clk_get_io(); |
206 | if (IS_ERR(clk)) { | |
207 | dev_err(&pdev->dev, "Failed to get clock\n"); | |
208 | return -ENOENT; | |
209 | } | |
2f58b8d0 JC |
210 | ltq_io_region_clk_rate = clk_get_rate(clk); |
211 | clk_put(clk); | |
212 | ||
cdb86121 | 213 | /* find out if the watchdog caused the last reboot */ |
2f58b8d0 JC |
214 | if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST) |
215 | ltq_wdt_bootstatus = WDIOF_CARDRESET; | |
216 | ||
cdb86121 | 217 | dev_info(&pdev->dev, "Init done\n"); |
2f58b8d0 JC |
218 | return misc_register(<q_wdt_miscdev); |
219 | } | |
220 | ||
4b12b896 | 221 | static int |
2f58b8d0 JC |
222 | ltq_wdt_remove(struct platform_device *pdev) |
223 | { | |
224 | misc_deregister(<q_wdt_miscdev); | |
225 | ||
2f58b8d0 JC |
226 | return 0; |
227 | } | |
228 | ||
cdb86121 JC |
229 | static const struct of_device_id ltq_wdt_match[] = { |
230 | { .compatible = "lantiq,wdt" }, | |
231 | {}, | |
232 | }; | |
233 | MODULE_DEVICE_TABLE(of, ltq_wdt_match); | |
2f58b8d0 JC |
234 | |
235 | static struct platform_driver ltq_wdt_driver = { | |
cdb86121 | 236 | .probe = ltq_wdt_probe, |
82268714 | 237 | .remove = ltq_wdt_remove, |
2f58b8d0 | 238 | .driver = { |
cdb86121 | 239 | .name = "wdt", |
2f58b8d0 | 240 | .owner = THIS_MODULE, |
cdb86121 | 241 | .of_match_table = ltq_wdt_match, |
2f58b8d0 JC |
242 | }, |
243 | }; | |
244 | ||
cdb86121 | 245 | module_platform_driver(ltq_wdt_driver); |
2f58b8d0 | 246 | |
86a1e189 | 247 | module_param(nowayout, bool, 0); |
2f58b8d0 | 248 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
2f58b8d0 JC |
249 | MODULE_AUTHOR("John Crispin <blogic@openwrt.org>"); |
250 | MODULE_DESCRIPTION("Lantiq SoC Watchdog"); | |
251 | MODULE_LICENSE("GPL"); |