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1 | // SPDX-License-Identifier: GPL-2.0+ | |
2 | /* | |
3 | * Watchdog driver for the SA11x0/PXA2xx | |
4 | * | |
5 | * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> | |
6 | * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk> | |
7 | * | |
8 | * Neither Oleg Drokin nor iXcelerator.com admit liability nor provide | |
9 | * warranty for any of this software. This material is provided | |
10 | * "AS-IS" and at no charge. | |
11 | * | |
12 | * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> | |
13 | * | |
14 | * 27/11/2000 Initial release | |
15 | */ | |
16 | ||
17 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
18 | ||
19 | #include <linux/module.h> | |
20 | #include <linux/moduleparam.h> | |
21 | #include <linux/clk.h> | |
22 | #include <linux/types.h> | |
23 | #include <linux/kernel.h> | |
24 | #include <linux/fs.h> | |
25 | #include <linux/miscdevice.h> | |
26 | #include <linux/watchdog.h> | |
27 | #include <linux/init.h> | |
28 | #include <linux/io.h> | |
29 | #include <linux/bitops.h> | |
30 | #include <linux/uaccess.h> | |
31 | #include <linux/timex.h> | |
32 | ||
33 | #ifdef CONFIG_ARCH_PXA | |
34 | #include <mach/regs-ost.h> | |
35 | #endif | |
36 | ||
37 | #include <mach/reset.h> | |
38 | #include <mach/hardware.h> | |
39 | ||
40 | static unsigned long oscr_freq; | |
41 | static unsigned long sa1100wdt_users; | |
42 | static unsigned int pre_margin; | |
43 | static int boot_status; | |
44 | ||
45 | /* | |
46 | * Allow only one person to hold it open | |
47 | */ | |
48 | static int sa1100dog_open(struct inode *inode, struct file *file) | |
49 | { | |
50 | if (test_and_set_bit(1, &sa1100wdt_users)) | |
51 | return -EBUSY; | |
52 | ||
53 | /* Activate SA1100 Watchdog timer */ | |
54 | writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3); | |
55 | writel_relaxed(OSSR_M3, OSSR); | |
56 | writel_relaxed(OWER_WME, OWER); | |
57 | writel_relaxed(readl_relaxed(OIER) | OIER_E3, OIER); | |
58 | return stream_open(inode, file); | |
59 | } | |
60 | ||
61 | /* | |
62 | * The watchdog cannot be disabled. | |
63 | * | |
64 | * Previous comments suggested that turning off the interrupt by | |
65 | * clearing OIER[E3] would prevent the watchdog timing out but this | |
66 | * does not appear to be true (at least on the PXA255). | |
67 | */ | |
68 | static int sa1100dog_release(struct inode *inode, struct file *file) | |
69 | { | |
70 | pr_crit("Device closed - timer will not stop\n"); | |
71 | clear_bit(1, &sa1100wdt_users); | |
72 | return 0; | |
73 | } | |
74 | ||
75 | static ssize_t sa1100dog_write(struct file *file, const char __user *data, | |
76 | size_t len, loff_t *ppos) | |
77 | { | |
78 | if (len) | |
79 | /* Refresh OSMR3 timer. */ | |
80 | writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3); | |
81 | return len; | |
82 | } | |
83 | ||
84 | static const struct watchdog_info ident = { | |
85 | .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT | |
86 | | WDIOF_KEEPALIVEPING, | |
87 | .identity = "SA1100/PXA255 Watchdog", | |
88 | .firmware_version = 1, | |
89 | }; | |
90 | ||
91 | static long sa1100dog_ioctl(struct file *file, unsigned int cmd, | |
92 | unsigned long arg) | |
93 | { | |
94 | int ret = -ENOTTY; | |
95 | int time; | |
96 | void __user *argp = (void __user *)arg; | |
97 | int __user *p = argp; | |
98 | ||
99 | switch (cmd) { | |
100 | case WDIOC_GETSUPPORT: | |
101 | ret = copy_to_user(argp, &ident, | |
102 | sizeof(ident)) ? -EFAULT : 0; | |
103 | break; | |
104 | ||
105 | case WDIOC_GETSTATUS: | |
106 | ret = put_user(0, p); | |
107 | break; | |
108 | ||
109 | case WDIOC_GETBOOTSTATUS: | |
110 | ret = put_user(boot_status, p); | |
111 | break; | |
112 | ||
113 | case WDIOC_KEEPALIVE: | |
114 | writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3); | |
115 | ret = 0; | |
116 | break; | |
117 | ||
118 | case WDIOC_SETTIMEOUT: | |
119 | ret = get_user(time, p); | |
120 | if (ret) | |
121 | break; | |
122 | ||
123 | if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) { | |
124 | ret = -EINVAL; | |
125 | break; | |
126 | } | |
127 | ||
128 | pre_margin = oscr_freq * time; | |
129 | writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3); | |
130 | fallthrough; | |
131 | ||
132 | case WDIOC_GETTIMEOUT: | |
133 | ret = put_user(pre_margin / oscr_freq, p); | |
134 | break; | |
135 | } | |
136 | return ret; | |
137 | } | |
138 | ||
139 | static const struct file_operations sa1100dog_fops = { | |
140 | .owner = THIS_MODULE, | |
141 | .llseek = no_llseek, | |
142 | .write = sa1100dog_write, | |
143 | .unlocked_ioctl = sa1100dog_ioctl, | |
144 | .compat_ioctl = compat_ptr_ioctl, | |
145 | .open = sa1100dog_open, | |
146 | .release = sa1100dog_release, | |
147 | }; | |
148 | ||
149 | static struct miscdevice sa1100dog_miscdev = { | |
150 | .minor = WATCHDOG_MINOR, | |
151 | .name = "watchdog", | |
152 | .fops = &sa1100dog_fops, | |
153 | }; | |
154 | ||
155 | static int margin __initdata = 60; /* (secs) Default is 1 minute */ | |
156 | static struct clk *clk; | |
157 | ||
158 | static int __init sa1100dog_init(void) | |
159 | { | |
160 | int ret; | |
161 | ||
162 | clk = clk_get(NULL, "OSTIMER0"); | |
163 | if (IS_ERR(clk)) { | |
164 | pr_err("SA1100/PXA2xx Watchdog Timer: clock not found: %d\n", | |
165 | (int) PTR_ERR(clk)); | |
166 | return PTR_ERR(clk); | |
167 | } | |
168 | ||
169 | ret = clk_prepare_enable(clk); | |
170 | if (ret) { | |
171 | pr_err("SA1100/PXA2xx Watchdog Timer: clock failed to prepare+enable: %d\n", | |
172 | ret); | |
173 | goto err; | |
174 | } | |
175 | ||
176 | oscr_freq = clk_get_rate(clk); | |
177 | ||
178 | /* | |
179 | * Read the reset status, and save it for later. If | |
180 | * we suspend, RCSR will be cleared, and the watchdog | |
181 | * reset reason will be lost. | |
182 | */ | |
183 | boot_status = (reset_status & RESET_STATUS_WATCHDOG) ? | |
184 | WDIOF_CARDRESET : 0; | |
185 | pre_margin = oscr_freq * margin; | |
186 | ||
187 | ret = misc_register(&sa1100dog_miscdev); | |
188 | if (ret == 0) { | |
189 | pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n", | |
190 | margin); | |
191 | return 0; | |
192 | } | |
193 | ||
194 | clk_disable_unprepare(clk); | |
195 | err: | |
196 | clk_put(clk); | |
197 | return ret; | |
198 | } | |
199 | ||
200 | static void __exit sa1100dog_exit(void) | |
201 | { | |
202 | misc_deregister(&sa1100dog_miscdev); | |
203 | clk_disable_unprepare(clk); | |
204 | clk_put(clk); | |
205 | } | |
206 | ||
207 | module_init(sa1100dog_init); | |
208 | module_exit(sa1100dog_exit); | |
209 | ||
210 | MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>"); | |
211 | MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog"); | |
212 | ||
213 | module_param(margin, int, 0); | |
214 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); | |
215 | ||
216 | MODULE_LICENSE("GPL"); |