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Philippe De Muyter88cce422010-11-03 15:07:28 +01001/*
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +01002 * drivers/watchdog/m54xx_wdt.c
Philippe De Muyter88cce422010-11-03 15:07:28 +01003 *
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +01004 * Watchdog driver for ColdFire MCF547x & MCF548x processors
Philippe De Muyter88cce422010-11-03 15:07:28 +01005 * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be>
6 *
7 * Adapted from the IXP4xx watchdog driver, which carries these notices:
8 *
9 * Author: Deepak Saxena <dsaxena@plexity.net>
10 *
11 * Copyright 2004 (c) MontaVista, Software, Inc.
12 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
13 *
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
17 */
18
Joe Perches27c766a2012-02-15 15:06:19 -080019#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
Philippe De Muyter88cce422010-11-03 15:07:28 +010021#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>
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +010034#include <asm/m54xxsim.h>
35#include <asm/m54xxgpt.h>
Philippe De Muyter88cce422010-11-03 15:07:28 +010036
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010037static bool nowayout = WATCHDOG_NOWAYOUT;
Philippe De Muyter88cce422010-11-03 15:07:28 +010038static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */
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 /* preserve GPIO usage, if any */
49 gms0 = __raw_readl(MCF_MBAR + 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_MBAR + MCF_GPT_GMS0);
56 __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) |
57 MCF_GPT_GCIR_CNT(0xffff), MCF_MBAR + MCF_GPT_GCIR0);
58 gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE;
59 __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
60}
61
62static void wdt_disable(void)
63{
64 unsigned int gms0;
65
66 /* disable watchdog */
67 gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
68 gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE);
69 __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
70}
71
72static void wdt_keepalive(void)
73{
74 unsigned int gms0;
75
76 gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0);
77 gms0 |= MCF_GPT_GMS_OCPW(0xA5);
78 __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0);
79}
80
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +010081static int m54xx_wdt_open(struct inode *inode, struct file *file)
Philippe De Muyter88cce422010-11-03 15:07:28 +010082{
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
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +010091static ssize_t m54xx_wdt_write(struct file *file, const char *data,
Philippe De Muyter88cce422010-11-03 15:07:28 +010092 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,
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100117 .identity = "Coldfire M54xx Watchdog",
Philippe De Muyter88cce422010-11-03 15:07:28 +0100118};
119
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100120static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd,
Philippe De Muyter88cce422010-11-03 15:07:28 +0100121 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 /* Fall through */
158
159 case WDIOC_GETTIMEOUT:
160 ret = put_user(heartbeat, (int *)arg);
161 break;
162 }
163 return ret;
164}
165
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100166static int m54xx_wdt_release(struct inode *inode, struct file *file)
Philippe De Muyter88cce422010-11-03 15:07:28 +0100167{
168 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
169 wdt_disable();
170 else {
Joe Perches27c766a2012-02-15 15:06:19 -0800171 pr_crit("Device closed unexpectedly - timer will not stop\n");
Philippe De Muyter88cce422010-11-03 15:07:28 +0100172 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
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100181static const struct file_operations m54xx_wdt_fops = {
Philippe De Muyter88cce422010-11-03 15:07:28 +0100182 .owner = THIS_MODULE,
183 .llseek = no_llseek,
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100184 .write = m54xx_wdt_write,
185 .unlocked_ioctl = m54xx_wdt_ioctl,
186 .open = m54xx_wdt_open,
187 .release = m54xx_wdt_release,
Philippe De Muyter88cce422010-11-03 15:07:28 +0100188};
189
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100190static struct miscdevice m54xx_wdt_miscdev = {
Philippe De Muyter88cce422010-11-03 15:07:28 +0100191 .minor = WATCHDOG_MINOR,
192 .name = "watchdog",
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100193 .fops = &m54xx_wdt_fops,
Philippe De Muyter88cce422010-11-03 15:07:28 +0100194};
195
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100196static int __init m54xx_wdt_init(void)
Philippe De Muyter88cce422010-11-03 15:07:28 +0100197{
198 if (!request_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4,
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100199 "Coldfire M54xx Watchdog")) {
Joe Perches27c766a2012-02-15 15:06:19 -0800200 pr_warn("I/O region busy\n");
Philippe De Muyter88cce422010-11-03 15:07:28 +0100201 return -EBUSY;
202 }
Joe Perches27c766a2012-02-15 15:06:19 -0800203 pr_info("driver is loaded\n");
Philippe De Muyter88cce422010-11-03 15:07:28 +0100204
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100205 return misc_register(&m54xx_wdt_miscdev);
Philippe De Muyter88cce422010-11-03 15:07:28 +0100206}
207
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100208static void __exit m54xx_wdt_exit(void)
Philippe De Muyter88cce422010-11-03 15:07:28 +0100209{
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100210 misc_deregister(&m54xx_wdt_miscdev);
Philippe De Muyter88cce422010-11-03 15:07:28 +0100211 release_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4);
212}
213
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100214module_init(m54xx_wdt_init);
215module_exit(m54xx_wdt_exit);
Philippe De Muyter88cce422010-11-03 15:07:28 +0100216
217MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>");
Philippe De Muyter9b9c63f2011-01-22 00:21:24 +0100218MODULE_DESCRIPTION("Coldfire M54xx Watchdog");
Philippe De Muyter88cce422010-11-03 15:07:28 +0100219
220module_param(heartbeat, int, 0);
221MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)");
222
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +0100223module_param(nowayout, bool, 0);
Philippe De Muyter88cce422010-11-03 15:07:28 +0100224MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
225
226MODULE_LICENSE("GPL");
227MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);