1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * drivers/watchdog/m54xx_wdt.c |
4 | * |
5 | * Watchdog driver for ColdFire MCF547x & MCF548x processors |
6 | * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be> |
7 | * |
8 | * Adapted from the IXP4xx watchdog driver, which carries these notices: |
9 | * |
10 | * Author: Deepak Saxena <dsaxena@plexity.net> |
11 | * |
12 | * Copyright 2004 (c) MontaVista, Software, Inc. |
13 | * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> |
14 | * |
15 | */ |
16 | |
17 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
18 | |
19 | #include <linux/module.h> |
20 | #include <linux/moduleparam.h> |
21 | #include <linux/types.h> |
22 | #include <linux/kernel.h> |
23 | #include <linux/fs.h> |
24 | #include <linux/miscdevice.h> |
25 | #include <linux/watchdog.h> |
26 | #include <linux/init.h> |
27 | #include <linux/bitops.h> |
28 | #include <linux/ioport.h> |
29 | #include <linux/uaccess.h> |
30 | #include <linux/io.h> |
31 | |
32 | #include <asm/coldfire.h> |
33 | #include <asm/m54xxsim.h> |
34 | #include <asm/m54xxgpt.h> |
35 | |
36 | static bool nowayout = WATCHDOG_NOWAYOUT; |
37 | static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */ |
38 | static unsigned long wdt_status; |
39 | |
40 | #define WDT_IN_USE 0 |
41 | #define WDT_OK_TO_CLOSE 1 |
42 | |
43 | static void wdt_enable(void) |
44 | { |
45 | unsigned int gms0; |
46 | |
47 | /* preserve GPIO usage, if any */ |
48 | gms0 = __raw_readl(addr: MCF_GPT_GMS0); |
49 | if (gms0 & MCF_GPT_GMS_TMS_GPIO) |
50 | gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK |
51 | | MCF_GPT_GMS_OD); |
52 | else |
53 | gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD; |
54 | __raw_writel(val: gms0, addr: MCF_GPT_GMS0); |
55 | __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) | |
56 | MCF_GPT_GCIR_CNT(0xffff), MCF_GPT_GCIR0); |
57 | gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE; |
58 | __raw_writel(val: gms0, addr: MCF_GPT_GMS0); |
59 | } |
60 | |
61 | static void wdt_disable(void) |
62 | { |
63 | unsigned int gms0; |
64 | |
65 | /* disable watchdog */ |
66 | gms0 = __raw_readl(addr: MCF_GPT_GMS0); |
67 | gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE); |
68 | __raw_writel(val: gms0, addr: MCF_GPT_GMS0); |
69 | } |
70 | |
71 | static void wdt_keepalive(void) |
72 | { |
73 | unsigned int gms0; |
74 | |
75 | gms0 = __raw_readl(addr: MCF_GPT_GMS0); |
76 | gms0 |= MCF_GPT_GMS_OCPW(0xA5); |
77 | __raw_writel(val: gms0, addr: MCF_GPT_GMS0); |
78 | } |
79 | |
80 | static int m54xx_wdt_open(struct inode *inode, struct file *file) |
81 | { |
82 | if (test_and_set_bit(WDT_IN_USE, addr: &wdt_status)) |
83 | return -EBUSY; |
84 | |
85 | clear_bit(WDT_OK_TO_CLOSE, addr: &wdt_status); |
86 | wdt_enable(); |
87 | return stream_open(inode, filp: file); |
88 | } |
89 | |
90 | static ssize_t m54xx_wdt_write(struct file *file, const char *data, |
91 | size_t len, loff_t *ppos) |
92 | { |
93 | if (len) { |
94 | if (!nowayout) { |
95 | size_t i; |
96 | |
97 | clear_bit(WDT_OK_TO_CLOSE, addr: &wdt_status); |
98 | |
99 | for (i = 0; i != len; i++) { |
100 | char c; |
101 | |
102 | if (get_user(c, data + i)) |
103 | return -EFAULT; |
104 | if (c == 'V') |
105 | set_bit(WDT_OK_TO_CLOSE, addr: &wdt_status); |
106 | } |
107 | } |
108 | wdt_keepalive(); |
109 | } |
110 | return len; |
111 | } |
112 | |
113 | static const struct watchdog_info ident = { |
114 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
115 | WDIOF_KEEPALIVEPING, |
116 | .identity = "Coldfire M54xx Watchdog" , |
117 | }; |
118 | |
119 | static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd, |
120 | unsigned long arg) |
121 | { |
122 | int ret = -ENOTTY; |
123 | int time; |
124 | |
125 | switch (cmd) { |
126 | case WDIOC_GETSUPPORT: |
127 | ret = copy_to_user(to: (struct watchdog_info *)arg, from: &ident, |
128 | n: sizeof(ident)) ? -EFAULT : 0; |
129 | break; |
130 | |
131 | case WDIOC_GETSTATUS: |
132 | ret = put_user(0, (int *)arg); |
133 | break; |
134 | |
135 | case WDIOC_GETBOOTSTATUS: |
136 | ret = put_user(0, (int *)arg); |
137 | break; |
138 | |
139 | case WDIOC_KEEPALIVE: |
140 | wdt_keepalive(); |
141 | ret = 0; |
142 | break; |
143 | |
144 | case WDIOC_SETTIMEOUT: |
145 | ret = get_user(time, (int *)arg); |
146 | if (ret) |
147 | break; |
148 | |
149 | if (time <= 0 || time > 30) { |
150 | ret = -EINVAL; |
151 | break; |
152 | } |
153 | |
154 | heartbeat = time; |
155 | wdt_enable(); |
156 | fallthrough; |
157 | |
158 | case WDIOC_GETTIMEOUT: |
159 | ret = put_user(heartbeat, (int *)arg); |
160 | break; |
161 | } |
162 | return ret; |
163 | } |
164 | |
165 | static int m54xx_wdt_release(struct inode *inode, struct file *file) |
166 | { |
167 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) |
168 | wdt_disable(); |
169 | else { |
170 | pr_crit("Device closed unexpectedly - timer will not stop\n" ); |
171 | wdt_keepalive(); |
172 | } |
173 | clear_bit(WDT_IN_USE, addr: &wdt_status); |
174 | clear_bit(WDT_OK_TO_CLOSE, addr: &wdt_status); |
175 | |
176 | return 0; |
177 | } |
178 | |
179 | |
180 | static const struct file_operations m54xx_wdt_fops = { |
181 | .owner = THIS_MODULE, |
182 | .llseek = no_llseek, |
183 | .write = m54xx_wdt_write, |
184 | .unlocked_ioctl = m54xx_wdt_ioctl, |
185 | .compat_ioctl = compat_ptr_ioctl, |
186 | .open = m54xx_wdt_open, |
187 | .release = m54xx_wdt_release, |
188 | }; |
189 | |
190 | static struct miscdevice m54xx_wdt_miscdev = { |
191 | .minor = WATCHDOG_MINOR, |
192 | .name = "watchdog" , |
193 | .fops = &m54xx_wdt_fops, |
194 | }; |
195 | |
196 | static int __init m54xx_wdt_init(void) |
197 | { |
198 | if (!request_mem_region(MCF_GPT_GCIR0, 4, "Coldfire M54xx Watchdog" )) { |
199 | pr_warn("I/O region busy\n" ); |
200 | return -EBUSY; |
201 | } |
202 | pr_info("driver is loaded\n" ); |
203 | |
204 | return misc_register(misc: &m54xx_wdt_miscdev); |
205 | } |
206 | |
207 | static void __exit m54xx_wdt_exit(void) |
208 | { |
209 | misc_deregister(misc: &m54xx_wdt_miscdev); |
210 | release_mem_region(MCF_GPT_GCIR0, 4); |
211 | } |
212 | |
213 | module_init(m54xx_wdt_init); |
214 | module_exit(m54xx_wdt_exit); |
215 | |
216 | MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>" ); |
217 | MODULE_DESCRIPTION("Coldfire M54xx Watchdog" ); |
218 | |
219 | module_param(heartbeat, int, 0); |
220 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)" ); |
221 | |
222 | module_param(nowayout, bool, 0); |
223 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started" ); |
224 | |
225 | MODULE_LICENSE("GPL" ); |
226 | |