blob: 088fd0c9d88811e81dfab7217d612ec950654d69 [file] [log] [blame]
John Crispin2f58b8d2011-05-05 23:00:23 +02001/*
2 * This program is free software; you can redistribute it and/or modify it
3 * under the terms of the GNU General Public License version 2 as published
4 * by the Free Software Foundation.
5 *
6 * Copyright (C) 2010 John Crispin <blogic@openwrt.org>
7 * Based on EP93xx wdt driver
8 */
9
Joe Perches27c766a2012-02-15 15:06:19 -080010#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
John Crispin2f58b8d2011-05-05 23:00:23 +020012#include <linux/module.h>
13#include <linux/fs.h>
14#include <linux/miscdevice.h>
15#include <linux/watchdog.h>
John Crispincdb86122012-04-12 21:21:56 +020016#include <linux/of_platform.h>
John Crispin2f58b8d2011-05-05 23:00:23 +020017#include <linux/uaccess.h>
18#include <linux/clk.h>
19#include <linux/io.h>
20
John Crispincdb86122012-04-12 21:21:56 +020021#include <lantiq_soc.h>
John Crispin2f58b8d2011-05-05 23:00:23 +020022
John Crispincdb86122012-04-12 21:21:56 +020023/*
24 * Section 3.4 of the datasheet
John Crispin2f58b8d2011-05-05 23:00:23 +020025 * The password sequence protects the WDT control register from unintended
26 * write actions, which might cause malfunction of the WDT.
27 *
28 * essentially the following two magic passwords need to be written to allow
29 * IO access to the WDT core
30 */
31#define LTQ_WDT_PW1 0x00BE0000
32#define LTQ_WDT_PW2 0x00DC0000
33
34#define LTQ_WDT_CR 0x0 /* watchdog control register */
35#define LTQ_WDT_SR 0x8 /* watchdog status register */
36
37#define LTQ_WDT_SR_EN (0x1 << 31) /* enable bit */
38#define LTQ_WDT_SR_PWD (0x3 << 26) /* turn on power */
39#define LTQ_WDT_SR_CLKDIV (0x3 << 24) /* turn on clock and set */
40 /* divider to 0x40000 */
41#define LTQ_WDT_DIVIDER 0x40000
42#define LTQ_MAX_TIMEOUT ((1 << 16) - 1) /* the reload field is 16 bit */
43
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010044static bool nowayout = WATCHDOG_NOWAYOUT;
John Crispin2f58b8d2011-05-05 23:00:23 +020045
46static void __iomem *ltq_wdt_membase;
47static unsigned long ltq_io_region_clk_rate;
48
49static unsigned long ltq_wdt_bootstatus;
50static unsigned long ltq_wdt_in_use;
51static int ltq_wdt_timeout = 30;
52static int ltq_wdt_ok_to_close;
53
54static void
55ltq_wdt_enable(void)
56{
John Crispin9cfce472011-08-24 10:31:39 +020057 unsigned long int timeout = ltq_wdt_timeout *
John Crispin2f58b8d2011-05-05 23:00:23 +020058 (ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000;
John Crispin9cfce472011-08-24 10:31:39 +020059 if (timeout > LTQ_MAX_TIMEOUT)
60 timeout = LTQ_MAX_TIMEOUT;
John Crispin2f58b8d2011-05-05 23:00:23 +020061
62 /* write the first password magic */
63 ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
64 /* write the second magic plus the configuration and new timeout */
65 ltq_w32(LTQ_WDT_SR_EN | LTQ_WDT_SR_PWD | LTQ_WDT_SR_CLKDIV |
John Crispin9cfce472011-08-24 10:31:39 +020066 LTQ_WDT_PW2 | timeout, ltq_wdt_membase + LTQ_WDT_CR);
John Crispin2f58b8d2011-05-05 23:00:23 +020067}
68
69static void
70ltq_wdt_disable(void)
71{
72 /* write the first password magic */
73 ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
John Crispincdb86122012-04-12 21:21:56 +020074 /*
75 * write the second password magic with no config
John Crispin2f58b8d2011-05-05 23:00:23 +020076 * this turns the watchdog off
77 */
78 ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR);
79}
80
81static ssize_t
82ltq_wdt_write(struct file *file, const char __user *data,
83 size_t len, loff_t *ppos)
84{
85 if (len) {
86 if (!nowayout) {
87 size_t i;
88
89 ltq_wdt_ok_to_close = 0;
90 for (i = 0; i != len; i++) {
91 char c;
92
93 if (get_user(c, data + i))
94 return -EFAULT;
95 if (c == 'V')
96 ltq_wdt_ok_to_close = 1;
97 else
98 ltq_wdt_ok_to_close = 0;
99 }
100 }
101 ltq_wdt_enable();
102 }
103
104 return len;
105}
106
107static struct watchdog_info ident = {
108 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
109 WDIOF_CARDRESET,
110 .identity = "ltq_wdt",
111};
112
113static long
114ltq_wdt_ioctl(struct file *file,
115 unsigned int cmd, unsigned long arg)
116{
117 int ret = -ENOTTY;
118
119 switch (cmd) {
120 case WDIOC_GETSUPPORT:
121 ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
122 sizeof(ident)) ? -EFAULT : 0;
123 break;
124
125 case WDIOC_GETBOOTSTATUS:
126 ret = put_user(ltq_wdt_bootstatus, (int __user *)arg);
127 break;
128
129 case WDIOC_GETSTATUS:
130 ret = put_user(0, (int __user *)arg);
131 break;
132
133 case WDIOC_SETTIMEOUT:
134 ret = get_user(ltq_wdt_timeout, (int __user *)arg);
135 if (!ret)
136 ltq_wdt_enable();
137 /* intentional drop through */
138 case WDIOC_GETTIMEOUT:
139 ret = put_user(ltq_wdt_timeout, (int __user *)arg);
140 break;
141
142 case WDIOC_KEEPALIVE:
143 ltq_wdt_enable();
144 ret = 0;
145 break;
146 }
147 return ret;
148}
149
150static int
151ltq_wdt_open(struct inode *inode, struct file *file)
152{
153 if (test_and_set_bit(0, &ltq_wdt_in_use))
154 return -EBUSY;
155 ltq_wdt_in_use = 1;
156 ltq_wdt_enable();
157
158 return nonseekable_open(inode, file);
159}
160
161static int
162ltq_wdt_release(struct inode *inode, struct file *file)
163{
164 if (ltq_wdt_ok_to_close)
165 ltq_wdt_disable();
166 else
Joe Perches27c766a2012-02-15 15:06:19 -0800167 pr_err("watchdog closed without warning\n");
John Crispin2f58b8d2011-05-05 23:00:23 +0200168 ltq_wdt_ok_to_close = 0;
169 clear_bit(0, &ltq_wdt_in_use);
170
171 return 0;
172}
173
174static const struct file_operations ltq_wdt_fops = {
175 .owner = THIS_MODULE,
176 .write = ltq_wdt_write,
177 .unlocked_ioctl = ltq_wdt_ioctl,
178 .open = ltq_wdt_open,
179 .release = ltq_wdt_release,
180 .llseek = no_llseek,
181};
182
183static struct miscdevice ltq_wdt_miscdev = {
184 .minor = WATCHDOG_MINOR,
185 .name = "watchdog",
186 .fops = &ltq_wdt_fops,
187};
188
Bill Pemberton2d991a12012-11-19 13:21:41 -0500189static int
John Crispin2f58b8d2011-05-05 23:00:23 +0200190ltq_wdt_probe(struct platform_device *pdev)
191{
192 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
193 struct clk *clk;
194
195 if (!res) {
196 dev_err(&pdev->dev, "cannot obtain I/O memory region");
197 return -ENOENT;
198 }
John Crispincdb86122012-04-12 21:21:56 +0200199
Thierry Reding4c271bb2013-01-21 11:09:25 +0100200 ltq_wdt_membase = devm_ioremap_resource(&pdev->dev, res);
201 if (IS_ERR(ltq_wdt_membase))
202 return PTR_ERR(ltq_wdt_membase);
John Crispin2f58b8d2011-05-05 23:00:23 +0200203
204 /* we do not need to enable the clock as it is always running */
John Crispincdb86122012-04-12 21:21:56 +0200205 clk = clk_get_io();
206 if (IS_ERR(clk)) {
207 dev_err(&pdev->dev, "Failed to get clock\n");
208 return -ENOENT;
209 }
John Crispin2f58b8d2011-05-05 23:00:23 +0200210 ltq_io_region_clk_rate = clk_get_rate(clk);
211 clk_put(clk);
212
John Crispincdb86122012-04-12 21:21:56 +0200213 /* find out if the watchdog caused the last reboot */
John Crispin2f58b8d2011-05-05 23:00:23 +0200214 if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST)
215 ltq_wdt_bootstatus = WDIOF_CARDRESET;
216
John Crispincdb86122012-04-12 21:21:56 +0200217 dev_info(&pdev->dev, "Init done\n");
John Crispin2f58b8d2011-05-05 23:00:23 +0200218 return misc_register(&ltq_wdt_miscdev);
219}
220
Bill Pemberton4b12b892012-11-19 13:26:24 -0500221static int
John Crispin2f58b8d2011-05-05 23:00:23 +0200222ltq_wdt_remove(struct platform_device *pdev)
223{
224 misc_deregister(&ltq_wdt_miscdev);
225
John Crispin2f58b8d2011-05-05 23:00:23 +0200226 return 0;
227}
228
John Crispincdb86122012-04-12 21:21:56 +0200229static const struct of_device_id ltq_wdt_match[] = {
230 { .compatible = "lantiq,wdt" },
231 {},
232};
233MODULE_DEVICE_TABLE(of, ltq_wdt_match);
John Crispin2f58b8d2011-05-05 23:00:23 +0200234
235static struct platform_driver ltq_wdt_driver = {
John Crispincdb86122012-04-12 21:21:56 +0200236 .probe = ltq_wdt_probe,
Bill Pemberton82268712012-11-19 13:21:12 -0500237 .remove = ltq_wdt_remove,
John Crispin2f58b8d2011-05-05 23:00:23 +0200238 .driver = {
John Crispincdb86122012-04-12 21:21:56 +0200239 .name = "wdt",
John Crispin2f58b8d2011-05-05 23:00:23 +0200240 .owner = THIS_MODULE,
John Crispincdb86122012-04-12 21:21:56 +0200241 .of_match_table = ltq_wdt_match,
John Crispin2f58b8d2011-05-05 23:00:23 +0200242 },
243};
244
John Crispincdb86122012-04-12 21:21:56 +0200245module_platform_driver(ltq_wdt_driver);
John Crispin2f58b8d2011-05-05 23:00:23 +0200246
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +0100247module_param(nowayout, bool, 0);
John Crispin2f58b8d2011-05-05 23:00:23 +0200248MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
John Crispin2f58b8d2011-05-05 23:00:23 +0200249MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
250MODULE_DESCRIPTION("Lantiq SoC Watchdog");
251MODULE_LICENSE("GPL");
252MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);