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1/*
2 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
3 *
4 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/types.h>
13#include <linux/miscdevice.h>
14#include <linux/watchdog.h>
15#include <linux/fs.h>
16#include <linux/init.h>
17#include <linux/uaccess.h>
18#include <linux/platform_device.h>
19#include <linux/clk.h>
20#include <linux/err.h>
21#include <linux/io.h>
22#include <asm/txx9tmr.h>
23
24#define TIMER_MARGIN 60 /* Default is 60 seconds */
25
26static int timeout = TIMER_MARGIN; /* in seconds */
27module_param(timeout, int, 0);
28MODULE_PARM_DESC(timeout,
29 "Watchdog timeout in seconds. "
30 "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
31 "default=" __MODULE_STRING(TIMER_MARGIN) ")");
32
33static int nowayout = WATCHDOG_NOWAYOUT;
34module_param(nowayout, int, 0);
35MODULE_PARM_DESC(nowayout,
36 "Watchdog cannot be stopped once started "
37 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
38
39#define WD_TIMER_CCD 7 /* 1/256 */
40#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
41#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
42
43static unsigned long txx9wdt_alive;
44static int expect_close;
45static struct txx9_tmr_reg __iomem *txx9wdt_reg;
46static struct clk *txx9_imclk;
47static DEFINE_SPINLOCK(txx9_lock);
48
49static void txx9wdt_ping(void)
50{
51 spin_lock(&txx9_lock);
52 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
53 spin_unlock(&txx9_lock);
54}
55
56static void txx9wdt_start(void)
57{
58 spin_lock(&txx9_lock);
59 __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
60 __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
61 __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
62 __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
63 &txx9wdt_reg->tcr);
64 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
65 spin_unlock(&txx9_lock);
66}
67
68static void txx9wdt_stop(void)
69{
70 spin_lock(&txx9_lock);
71 __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
72 __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
73 &txx9wdt_reg->tcr);
74 spin_unlock(&txx9_lock);
75}
76
77static int txx9wdt_open(struct inode *inode, struct file *file)
78{
79 if (test_and_set_bit(0, &txx9wdt_alive))
80 return -EBUSY;
81
82 if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
83 clear_bit(0, &txx9wdt_alive);
84 return -EBUSY;
85 }
86
87 if (nowayout)
88 __module_get(THIS_MODULE);
89
90 txx9wdt_start();
91 return nonseekable_open(inode, file);
92}
93
94static int txx9wdt_release(struct inode *inode, struct file *file)
95{
96 if (expect_close)
97 txx9wdt_stop();
98 else {
99 printk(KERN_CRIT "txx9wdt: "
100 "Unexpected close, not stopping watchdog!\n");
101 txx9wdt_ping();
102 }
103 clear_bit(0, &txx9wdt_alive);
104 expect_close = 0;
105 return 0;
106}
107
108static ssize_t txx9wdt_write(struct file *file, const char __user *data,
109 size_t len, loff_t *ppos)
110{
111 if (len) {
112 if (!nowayout) {
113 size_t i;
114
115 expect_close = 0;
116 for (i = 0; i != len; i++) {
117 char c;
118 if (get_user(c, data + i))
119 return -EFAULT;
120 if (c == 'V')
121 expect_close = 1;
122 }
123 }
124 txx9wdt_ping();
125 }
126 return len;
127}
128
129static long txx9wdt_ioctl(struct file *file, unsigned int cmd,
130 unsigned long arg)
131{
132 void __user *argp = (void __user *)arg;
133 int __user *p = argp;
134 int new_timeout;
135 static const struct watchdog_info ident = {
136 .options = WDIOF_SETTIMEOUT |
137 WDIOF_KEEPALIVEPING |
138 WDIOF_MAGICCLOSE,
139 .firmware_version = 0,
140 .identity = "Hardware Watchdog for TXx9",
141 };
142
143 switch (cmd) {
144 case WDIOC_GETSUPPORT:
145 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
146 case WDIOC_GETSTATUS:
147 case WDIOC_GETBOOTSTATUS:
148 return put_user(0, p);
149 case WDIOC_KEEPALIVE:
150 txx9wdt_ping();
151 return 0;
152 case WDIOC_SETTIMEOUT:
153 if (get_user(new_timeout, p))
154 return -EFAULT;
155 if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT)
156 return -EINVAL;
157 timeout = new_timeout;
158 txx9wdt_stop();
159 txx9wdt_start();
160 /* Fall */
161 case WDIOC_GETTIMEOUT:
162 return put_user(timeout, p);
163 default:
164 return -ENOTTY;
165 }
166}
167
168static const struct file_operations txx9wdt_fops = {
169 .owner = THIS_MODULE,
170 .llseek = no_llseek,
171 .write = txx9wdt_write,
172 .unlocked_ioctl = txx9wdt_ioctl,
173 .open = txx9wdt_open,
174 .release = txx9wdt_release,
175};
176
177static struct miscdevice txx9wdt_miscdev = {
178 .minor = WATCHDOG_MINOR,
179 .name = "watchdog",
180 .fops = &txx9wdt_fops,
181};
182
183static int __init txx9wdt_probe(struct platform_device *dev)
184{
185 struct resource *res;
186 int ret;
187
188 txx9_imclk = clk_get(NULL, "imbus_clk");
189 if (IS_ERR(txx9_imclk)) {
190 ret = PTR_ERR(txx9_imclk);
191 txx9_imclk = NULL;
192 goto exit;
193 }
194 ret = clk_enable(txx9_imclk);
195 if (ret) {
196 clk_put(txx9_imclk);
197 txx9_imclk = NULL;
198 goto exit;
199 }
200
201 res = platform_get_resource(dev, IORESOURCE_MEM, 0);
202 if (!res)
203 goto exit_busy;
204 if (!devm_request_mem_region(&dev->dev, res->start, resource_size(res),
205 "txx9wdt"))
206 goto exit_busy;
207 txx9wdt_reg = devm_ioremap(&dev->dev, res->start, resource_size(res));
208 if (!txx9wdt_reg)
209 goto exit_busy;
210
211 ret = misc_register(&txx9wdt_miscdev);
212 if (ret) {
213 goto exit;
214 }
215
216 printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
217 "timeout=%d sec (max %ld) (nowayout= %d)\n",
218 timeout, WD_MAX_TIMEOUT, nowayout);
219
220 return 0;
221exit_busy:
222 ret = -EBUSY;
223exit:
224 if (txx9_imclk) {
225 clk_disable(txx9_imclk);
226 clk_put(txx9_imclk);
227 }
228 return ret;
229}
230
231static int __exit txx9wdt_remove(struct platform_device *dev)
232{
233 misc_deregister(&txx9wdt_miscdev);
234 clk_disable(txx9_imclk);
235 clk_put(txx9_imclk);
236 return 0;
237}
238
239static void txx9wdt_shutdown(struct platform_device *dev)
240{
241 txx9wdt_stop();
242}
243
244static struct platform_driver txx9wdt_driver = {
245 .remove = __exit_p(txx9wdt_remove),
246 .shutdown = txx9wdt_shutdown,
247 .driver = {
248 .name = "txx9wdt",
249 .owner = THIS_MODULE,
250 },
251};
252
253static int __init watchdog_init(void)
254{
255 return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
256}
257
258static void __exit watchdog_exit(void)
259{
260 platform_driver_unregister(&txx9wdt_driver);
261}
262
263module_init(watchdog_init);
264module_exit(watchdog_exit);
265
266MODULE_DESCRIPTION("TXx9 Watchdog Driver");
267MODULE_LICENSE("GPL");
268MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
269MODULE_ALIAS("platform:txx9wdt");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
4 *
5 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
6 */
7
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10#include <linux/module.h>
11#include <linux/moduleparam.h>
12#include <linux/types.h>
13#include <linux/watchdog.h>
14#include <linux/init.h>
15#include <linux/platform_device.h>
16#include <linux/clk.h>
17#include <linux/err.h>
18#include <linux/io.h>
19#include <asm/txx9tmr.h>
20
21#define WD_TIMER_CCD 7 /* 1/256 */
22#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
23#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
24#define TIMER_MARGIN 60 /* Default is 60 seconds */
25
26static unsigned int timeout = TIMER_MARGIN; /* in seconds */
27module_param(timeout, uint, 0);
28MODULE_PARM_DESC(timeout,
29 "Watchdog timeout in seconds. "
30 "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
31 "default=" __MODULE_STRING(TIMER_MARGIN) ")");
32
33static bool nowayout = WATCHDOG_NOWAYOUT;
34module_param(nowayout, bool, 0);
35MODULE_PARM_DESC(nowayout,
36 "Watchdog cannot be stopped once started "
37 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
38
39static struct txx9_tmr_reg __iomem *txx9wdt_reg;
40static struct clk *txx9_imclk;
41static DEFINE_SPINLOCK(txx9_lock);
42
43static int txx9wdt_ping(struct watchdog_device *wdt_dev)
44{
45 spin_lock(&txx9_lock);
46 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
47 spin_unlock(&txx9_lock);
48 return 0;
49}
50
51static int txx9wdt_start(struct watchdog_device *wdt_dev)
52{
53 spin_lock(&txx9_lock);
54 __raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra);
55 __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
56 __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
57 __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
58 &txx9wdt_reg->tcr);
59 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
60 spin_unlock(&txx9_lock);
61 return 0;
62}
63
64static int txx9wdt_stop(struct watchdog_device *wdt_dev)
65{
66 spin_lock(&txx9_lock);
67 __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
68 __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
69 &txx9wdt_reg->tcr);
70 spin_unlock(&txx9_lock);
71 return 0;
72}
73
74static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev,
75 unsigned int new_timeout)
76{
77 wdt_dev->timeout = new_timeout;
78 txx9wdt_stop(wdt_dev);
79 txx9wdt_start(wdt_dev);
80 return 0;
81}
82
83static const struct watchdog_info txx9wdt_info = {
84 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
85 .identity = "Hardware Watchdog for TXx9",
86};
87
88static const struct watchdog_ops txx9wdt_ops = {
89 .owner = THIS_MODULE,
90 .start = txx9wdt_start,
91 .stop = txx9wdt_stop,
92 .ping = txx9wdt_ping,
93 .set_timeout = txx9wdt_set_timeout,
94};
95
96static struct watchdog_device txx9wdt = {
97 .info = &txx9wdt_info,
98 .ops = &txx9wdt_ops,
99};
100
101static int __init txx9wdt_probe(struct platform_device *dev)
102{
103 int ret;
104
105 txx9_imclk = clk_get(NULL, "imbus_clk");
106 if (IS_ERR(txx9_imclk)) {
107 ret = PTR_ERR(txx9_imclk);
108 txx9_imclk = NULL;
109 goto exit;
110 }
111 ret = clk_prepare_enable(txx9_imclk);
112 if (ret) {
113 clk_put(txx9_imclk);
114 txx9_imclk = NULL;
115 goto exit;
116 }
117
118 txx9wdt_reg = devm_platform_ioremap_resource(dev, 0);
119 if (IS_ERR(txx9wdt_reg)) {
120 ret = PTR_ERR(txx9wdt_reg);
121 goto exit;
122 }
123
124 if (timeout < 1 || timeout > WD_MAX_TIMEOUT)
125 timeout = TIMER_MARGIN;
126 txx9wdt.timeout = timeout;
127 txx9wdt.min_timeout = 1;
128 txx9wdt.max_timeout = WD_MAX_TIMEOUT;
129 txx9wdt.parent = &dev->dev;
130 watchdog_set_nowayout(&txx9wdt, nowayout);
131
132 ret = watchdog_register_device(&txx9wdt);
133 if (ret)
134 goto exit;
135
136 pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n",
137 timeout, WD_MAX_TIMEOUT, nowayout);
138
139 return 0;
140exit:
141 if (txx9_imclk) {
142 clk_disable_unprepare(txx9_imclk);
143 clk_put(txx9_imclk);
144 }
145 return ret;
146}
147
148static int __exit txx9wdt_remove(struct platform_device *dev)
149{
150 watchdog_unregister_device(&txx9wdt);
151 clk_disable_unprepare(txx9_imclk);
152 clk_put(txx9_imclk);
153 return 0;
154}
155
156static void txx9wdt_shutdown(struct platform_device *dev)
157{
158 txx9wdt_stop(&txx9wdt);
159}
160
161static struct platform_driver txx9wdt_driver = {
162 .remove = __exit_p(txx9wdt_remove),
163 .shutdown = txx9wdt_shutdown,
164 .driver = {
165 .name = "txx9wdt",
166 },
167};
168
169module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe);
170
171MODULE_DESCRIPTION("TXx9 Watchdog Driver");
172MODULE_LICENSE("GPL");
173MODULE_ALIAS("platform:txx9wdt");