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