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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
108static const struct watchdog_info ixp4xx_wdt_info = {
109 .options = WDIOF_KEEPALIVEPING
110 | WDIOF_MAGICCLOSE
111 | WDIOF_SETTIMEOUT,
112 .identity = KBUILD_MODNAME,
113};
114
115/* Devres-handled clock disablement */
116static void ixp4xx_clock_action(void *d)
117{
118 clk_disable_unprepare(d);
119}
120
121static int ixp4xx_wdt_probe(struct platform_device *pdev)
122{
123 struct device *dev = &pdev->dev;
124 struct ixp4xx_wdt *iwdt;
125 struct clk *clk;
126 int ret;
127
128 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
129 dev_err(dev, "Rev. A0 IXP42x CPU detected - watchdog disabled\n");
130 return -ENODEV;
131 }
132
133 iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL);
134 if (!iwdt)
135 return -ENOMEM;
136 iwdt->base = (void __iomem *)dev->platform_data;
137
138 /*
139 * Retrieve rate from a fixed clock from the device tree if
140 * the parent has that, else use the default clock rate.
141 */
142 clk = devm_clk_get(dev->parent, NULL);
143 if (!IS_ERR(clk)) {
144 ret = clk_prepare_enable(clk);
145 if (ret)
146 return ret;
147 ret = devm_add_action_or_reset(dev, ixp4xx_clock_action, clk);
148 if (ret)
149 return ret;
150 iwdt->rate = clk_get_rate(clk);
151 }
152 if (!iwdt->rate)
153 iwdt->rate = IXP4XX_TIMER_FREQ;
154
155 iwdt->wdd.info = &ixp4xx_wdt_info;
156 iwdt->wdd.ops = &ixp4xx_wdt_ops;
157 iwdt->wdd.min_timeout = 1;
158 iwdt->wdd.max_timeout = U32_MAX / iwdt->rate;
159 iwdt->wdd.parent = dev;
160 /* Default to 60 seconds */
161 iwdt->wdd.timeout = 60U;
162 watchdog_init_timeout(&iwdt->wdd, 0, dev);
163
164 if (__raw_readl(iwdt->base + IXP4XX_OSST_OFFSET) &
165 IXP4XX_OSST_TIMER_WARM_RESET)
166 iwdt->wdd.bootstatus = WDIOF_CARDRESET;
167
168 ret = devm_watchdog_register_device(dev, &iwdt->wdd);
169 if (ret)
170 return ret;
171
172 dev_info(dev, "IXP4xx watchdog available\n");
173
174 return 0;
175}
176
177static struct platform_driver ixp4xx_wdt_driver = {
178 .probe = ixp4xx_wdt_probe,
179 .driver = {
180 .name = "ixp4xx-watchdog",
181 },
182};
183module_platform_driver(ixp4xx_wdt_driver);
184
185MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
186MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
187MODULE_LICENSE("GPL");
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/types.h>
21#include <linux/kernel.h>
22#include <linux/fs.h>
23#include <linux/miscdevice.h>
24#include <linux/watchdog.h>
25#include <linux/init.h>
26#include <linux/bitops.h>
27#include <linux/uaccess.h>
28#include <mach/hardware.h>
29
30static bool nowayout = WATCHDOG_NOWAYOUT;
31static int heartbeat = 60; /* (secs) Default is 1 minute */
32static unsigned long wdt_status;
33static unsigned long boot_status;
34static DEFINE_SPINLOCK(wdt_lock);
35
36#define WDT_TICK_RATE (IXP4XX_PERIPHERAL_BUS_CLOCK * 1000000UL)
37
38#define WDT_IN_USE 0
39#define WDT_OK_TO_CLOSE 1
40
41static void wdt_enable(void)
42{
43 spin_lock(&wdt_lock);
44 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
45 *IXP4XX_OSWE = 0;
46 *IXP4XX_OSWT = WDT_TICK_RATE * heartbeat;
47 *IXP4XX_OSWE = IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE;
48 *IXP4XX_OSWK = 0;
49 spin_unlock(&wdt_lock);
50}
51
52static void wdt_disable(void)
53{
54 spin_lock(&wdt_lock);
55 *IXP4XX_OSWK = IXP4XX_WDT_KEY;
56 *IXP4XX_OSWE = 0;
57 *IXP4XX_OSWK = 0;
58 spin_unlock(&wdt_lock);
59}
60
61static int ixp4xx_wdt_open(struct inode *inode, struct file *file)
62{
63 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
64 return -EBUSY;
65
66 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
67 wdt_enable();
68 return nonseekable_open(inode, file);
69}
70
71static ssize_t
72ixp4xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos)
73{
74 if (len) {
75 if (!nowayout) {
76 size_t i;
77
78 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
79
80 for (i = 0; i != len; i++) {
81 char c;
82
83 if (get_user(c, data + i))
84 return -EFAULT;
85 if (c == 'V')
86 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
87 }
88 }
89 wdt_enable();
90 }
91 return len;
92}
93
94static const struct watchdog_info ident = {
95 .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE |
96 WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
97 .identity = "IXP4xx Watchdog",
98};
99
100
101static long ixp4xx_wdt_ioctl(struct file *file, unsigned int cmd,
102 unsigned long arg)
103{
104 int ret = -ENOTTY;
105 int time;
106
107 switch (cmd) {
108 case WDIOC_GETSUPPORT:
109 ret = copy_to_user((struct watchdog_info *)arg, &ident,
110 sizeof(ident)) ? -EFAULT : 0;
111 break;
112
113 case WDIOC_GETSTATUS:
114 ret = put_user(0, (int *)arg);
115 break;
116
117 case WDIOC_GETBOOTSTATUS:
118 ret = put_user(boot_status, (int *)arg);
119 break;
120
121 case WDIOC_KEEPALIVE:
122 wdt_enable();
123 ret = 0;
124 break;
125
126 case WDIOC_SETTIMEOUT:
127 ret = get_user(time, (int *)arg);
128 if (ret)
129 break;
130
131 if (time <= 0 || time > 60) {
132 ret = -EINVAL;
133 break;
134 }
135
136 heartbeat = time;
137 wdt_enable();
138 /* Fall through */
139
140 case WDIOC_GETTIMEOUT:
141 ret = put_user(heartbeat, (int *)arg);
142 break;
143 }
144 return ret;
145}
146
147static int ixp4xx_wdt_release(struct inode *inode, struct file *file)
148{
149 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
150 wdt_disable();
151 else
152 pr_crit("Device closed unexpectedly - timer will not stop\n");
153 clear_bit(WDT_IN_USE, &wdt_status);
154 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
155
156 return 0;
157}
158
159
160static const struct file_operations ixp4xx_wdt_fops = {
161 .owner = THIS_MODULE,
162 .llseek = no_llseek,
163 .write = ixp4xx_wdt_write,
164 .unlocked_ioctl = ixp4xx_wdt_ioctl,
165 .open = ixp4xx_wdt_open,
166 .release = ixp4xx_wdt_release,
167};
168
169static struct miscdevice ixp4xx_wdt_miscdev = {
170 .minor = WATCHDOG_MINOR,
171 .name = "watchdog",
172 .fops = &ixp4xx_wdt_fops,
173};
174
175static int __init ixp4xx_wdt_init(void)
176{
177 int ret;
178
179 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {
180 pr_err("Rev. A0 IXP42x CPU detected - watchdog disabled\n");
181
182 return -ENODEV;
183 }
184 boot_status = (*IXP4XX_OSST & IXP4XX_OSST_TIMER_WARM_RESET) ?
185 WDIOF_CARDRESET : 0;
186 ret = misc_register(&ixp4xx_wdt_miscdev);
187 if (ret == 0)
188 pr_info("timer heartbeat %d sec\n", heartbeat);
189 return ret;
190}
191
192static void __exit ixp4xx_wdt_exit(void)
193{
194 misc_deregister(&ixp4xx_wdt_miscdev);
195}
196
197
198module_init(ixp4xx_wdt_init);
199module_exit(ixp4xx_wdt_exit);
200
201MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
202MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");
203
204module_param(heartbeat, int, 0);
205MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
206
207module_param(nowayout, bool, 0);
208MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
209
210MODULE_LICENSE("GPL");