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1/*
2 * drivers/char/watchdog/ixp4xx_wdt.c
3 *
4 * Watchdog driver for Intel IXP4xx network processors
5 *
6 * Author: Deepak Saxena <dsaxena@plexity.net>
7 *
8 * Copyright 2004 (c) MontaVista, Software, Inc.
9 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
10 *
11 * This file is licensed under the terms of the GNU General Public
12 * License version 2. This program is licensed "as is" without any
13 * warranty of any kind, whether express or implied.
14 */
15
16#include <linux/module.h>
17#include <linux/moduleparam.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/fs.h>
21#include <linux/miscdevice.h>
22#include <linux/watchdog.h>
23#include <linux/init.h>
24#include <linux/bitops.h>
25#include <linux/uaccess.h>
26#include <mach/hardware.h>
27
28static int nowayout = WATCHDOG_NOWAYOUT;
29static int heartbeat = 60; /* (secs) Default is 1 minute */
30static unsigned long wdt_status;
31static unsigned long boot_status;
32static DEFINE_SPINLOCK(wdt_lock);
33
34#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
35
36#define WDT_IN_USE 0
37#define WDT_OK_TO_CLOSE 1
38
39static void wdt_enable(void)
40{
41 spin_lock(&wdt_lock);
42 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
43 *IXP4XX_OSWE = 0;
44 *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
45 *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
46 *IXP4XX_OSWK = 0;
47 spin_unlock(&wdt_lock);
48}
49
50static void wdt_disable(void)
51{
52 spin_lock(&wdt_lock);
53 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
54 *IXP4XX_OSWE = 0;
55 *IXP4XX_OSWK = 0;
56 spin_unlock(&wdt_lock);
57}
58
59static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
60{
61 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
62 return -EBUSY;
63
64 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
65 wdt_enable();
66 return nonseekable_open(inode, file);
67}
68
69static ssize_t
70ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
71{
72 if (len) {
73 if (!nowayout) {
74 size_t i;
75
76 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
77
78 for (i = 0; i != len; i++) {
79 char c;
80
81 if (get_user(c, data + i))
82 return -EFAULT;
83 if (c == 'V')
84 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
85 }
86 }
87 wdt_enable();
88 }
89 return len;
90}
91
92static const struct watchdog_info ident = {
93 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
94 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
95 .identity = "IXP4xx Watchdog",
96};
97
98
99static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
100 unsigned long arg)
101{
102 int ret = -ENOTTY;
103 int time;
104
105 switch (cmd) {
106 case WDIOC_GETSUPPORT:
107 ret = copy_to_user((struct watchdog_info *)arg, &ident,
108 sizeof(ident)) ? -EFAULT : 0;
109 break;
110
111 case WDIOC_GETSTATUS:
112 ret = put_user(0, (int *)arg);
113 break;
114
115 case WDIOC_GETBOOTSTATUS:
116 ret = put_user(boot_status, (int *)arg);
117 break;
118
119 case WDIOC_KEEPALIVE:
120 wdt_enable();
121 ret = 0;
122 break;
123
124 case WDIOC_SETTIMEOUT:
125 ret = get_user(time, (int *)arg);
126 if (ret)
127 break;
128
129 if (time <= 0 || time > 60) {
130 ret = -EINVAL;
131 break;
132 }
133
134 heartbeat = time;
135 wdt_enable();
136 /* Fall through */
137
138 case WDIOC_GETTIMEOUT:
139 ret = put_user(heartbeat, (int *)arg);
140 break;
141 }
142 return ret;
143}
144
145static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
146{
147 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
148 wdt_disable();
149 else
150 printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
151 "timer will not stop\n");
152 clear_bit(WDT_IN_USE, &wdt_status);
153 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
154
155 return 0;
156}
157
158
159static const struct file_operations ixp4xx_wdt_fops = {
160 .owner = THIS_MODULE,
161 .llseek = no_llseek,
162 .write = ixp4xx_wdt_write,
163 .unlocked_ioctl = ixp4xx_wdt_ioctl,
164 .open = ixp4xx_wdt_open,
165 .release = ixp4xx_wdt_release,
166};
167
168static struct miscdevice ixp4xx_wdt_miscdev = {
169 .minor = WATCHDOG_MINOR,
170 .name = "watchdog",
171 .fops = &ixp4xx_wdt_fops,
172};
173
174static int __init ixp4xx_wdt_init(void)
175{
176 int ret;
177
178 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
179 printk(KERN_ERR "IXP4XXX Watchdog: Rev. A0 IXP42x CPU detected"
180 " - watchdog disabled\n");
181
182 return -ENODEV;
183 }
184 spin_lock_init(&wdt_lock);
185 boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
186 WDIOF_CARDRESET : 0;
187 ret = misc_register(&ixp4xx_wdt_miscdev);
188 if (ret == 0)
189 printk(KERN_INFO "IXP4xx Watchdog Timer: heartbeat %d sec\n",
190 heartbeat);
191 return ret;
192}
193
194static void __exit ixp4xx_wdt_exit(void)
195{
196 misc_deregister(&ixp4xx_wdt_miscdev);
197}
198
199
200module_init(ixp4xx_wdt_init);
201module_exit(ixp4xx_wdt_exit);
202
203MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
204MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
205
206module_param(heartbeat, int, 0);
207MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
208
209module_param(nowayout, int, 0);
210MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
211
212MODULE_LICENSE("GPL");
213MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
214
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/char/watchdog/ixp4xx_wdt.c
4 *
5 * Watchdog driver for Intel IXP4xx network processors
6 *
7 * Author: Deepak Saxena <dsaxena@plexity.net>
8 * Author: Linus Walleij <linus.walleij@linaro.org>
9 *
10 * Copyright 2004 (c) MontaVista, Software, Inc.
11 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
12 */
13
14#include <linux/module.h>
15#include <linux/types.h>
16#include <linux/kernel.h>
17#include <linux/watchdog.h>
18#include <linux/bits.h>
19#include <linux/platform_device.h>
20#include <linux/clk.h>
21#include <linux/soc/ixp4xx/cpu.h>
22
23struct ixp4xx_wdt {
24 struct watchdog_device wdd;
25 void __iomem *base;
26 unsigned long rate;
27};
28
29/* Fallback if we do not have a clock for this */
30#define IXP4XX_TIMER_FREQ 66666000
31
32/* Registers after the timer registers */
33#define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */
34#define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */
35#define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */
36#define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */
37
38#define IXP4XX_OSST_TIMER_WDOG_PEND 0x00000008
39#define IXP4XX_OSST_TIMER_WARM_RESET 0x00000010
40#define IXP4XX_WDT_KEY 0x0000482E
41#define IXP4XX_WDT_RESET_ENABLE 0x00000001
42#define IXP4XX_WDT_IRQ_ENABLE 0x00000002
43#define IXP4XX_WDT_COUNT_ENABLE 0x00000004
44
45static inline
46struct ixp4xx_wdt *to_ixp4xx_wdt(struct watchdog_device *wdd)
47{
48 return container_of(wdd, struct ixp4xx_wdt, wdd);
49}
50
51static int ixp4xx_wdt_start(struct watchdog_device *wdd)
52{
53 struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);
54
55 __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);
56 __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET);
57 __raw_writel(wdd->timeout * iwdt->rate,
58 iwdt->base + IXP4XX_OSWT_OFFSET);
59 __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE,
60 iwdt->base + IXP4XX_OSWE_OFFSET);
61 __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET);
62
63 return 0;
64}
65
66static int ixp4xx_wdt_stop(struct watchdog_device *wdd)
67{
68 struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);
69
70 __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);
71 __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET);
72 __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET);
73
74 return 0;
75}
76
77static int ixp4xx_wdt_set_timeout(struct watchdog_device *wdd,
78 unsigned int timeout)
79{
80 wdd->timeout = timeout;
81 if (watchdog_active(wdd))
82 ixp4xx_wdt_start(wdd);
83
84 return 0;
85}
86
87static int ixp4xx_wdt_restart(struct watchdog_device *wdd,
88 unsigned long action, void *data)
89{
90 struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);
91
92 __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);
93 __raw_writel(0, iwdt->base + IXP4XX_OSWT_OFFSET);
94 __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE,
95 iwdt->base + IXP4XX_OSWE_OFFSET);
96
97 return 0;
98}
99
100static const struct watchdog_ops ixp4xx_wdt_ops = {
101 .start = ixp4xx_wdt_start,
102 .stop = ixp4xx_wdt_stop,
103 .set_timeout = ixp4xx_wdt_set_timeout,
104 .restart = ixp4xx_wdt_restart,
105 .owner = THIS_MODULE,
106};
107
108/*
109 * The A0 version of the IXP422 had a bug in the watchdog making
110 * is useless, but we still need to use it to restart the system
111 * as it is the only way, so in this special case we register a
112 * "dummy" watchdog that doesn't really work, but will support
113 * the restart operation.
114 */
115static int ixp4xx_wdt_dummy(struct watchdog_device *wdd)
116{
117 return 0;
118}
119
120static const struct watchdog_ops ixp4xx_wdt_restart_only_ops = {
121 .start = ixp4xx_wdt_dummy,
122 .stop = ixp4xx_wdt_dummy,
123 .restart = ixp4xx_wdt_restart,
124 .owner = THIS_MODULE,
125};
126
127static const struct watchdog_info ixp4xx_wdt_info = {
128 .options = WDIOF_KEEPALIVEPING
129 | WDIOF_MAGICCLOSE
130 | WDIOF_SETTIMEOUT,
131 .identity = KBUILD_MODNAME,
132};
133
134static int ixp4xx_wdt_probe(struct platform_device *pdev)
135{
136 static const struct watchdog_ops *iwdt_ops;
137 struct device *dev = &pdev->dev;
138 struct ixp4xx_wdt *iwdt;
139 struct clk *clk;
140 int ret;
141
142 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
143 dev_info(dev, "Rev. A0 IXP42x CPU detected - only restart supported\n");
144 iwdt_ops = &ixp4xx_wdt_restart_only_ops;
145 } else {
146 iwdt_ops = &ixp4xx_wdt_ops;
147 }
148
149 iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL);
150 if (!iwdt)
151 return -ENOMEM;
152 iwdt->base = (void __iomem *)dev->platform_data;
153
154 /*
155 * Retrieve rate from a fixed clock from the device tree if
156 * the parent has that, else use the default clock rate.
157 */
158 clk = devm_clk_get_enabled(dev->parent, NULL);
159 if (!IS_ERR(clk))
160 iwdt->rate = clk_get_rate(clk);
161
162 if (!iwdt->rate)
163 iwdt->rate = IXP4XX_TIMER_FREQ;
164
165 iwdt->wdd.info = &ixp4xx_wdt_info;
166 iwdt->wdd.ops = iwdt_ops;
167 iwdt->wdd.min_timeout = 1;
168 iwdt->wdd.max_timeout = U32_MAX / iwdt->rate;
169 iwdt->wdd.parent = dev;
170 /* Default to 60 seconds */
171 iwdt->wdd.timeout = 60U;
172 watchdog_init_timeout(&iwdt->wdd, 0, dev);
173
174 if (__raw_readl(iwdt->base + IXP4XX_OSST_OFFSET) &
175 IXP4XX_OSST_TIMER_WARM_RESET)
176 iwdt->wdd.bootstatus = WDIOF_CARDRESET;
177
178 ret = devm_watchdog_register_device(dev, &iwdt->wdd);
179 if (ret)
180 return ret;
181
182 dev_info(dev, "IXP4xx watchdog available\n");
183
184 return 0;
185}
186
187static struct platform_driver ixp4xx_wdt_driver = {
188 .probe = ixp4xx_wdt_probe,
189 .driver = {
190 .name = "ixp4xx-watchdog",
191 },
192};
193module_platform_driver(ixp4xx_wdt_driver);
194
195MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
196MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
197MODULE_LICENSE("GPL");