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1/*
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
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/module.h>
13#include <linux/fs.h>
14#include <linux/miscdevice.h>
15#include <linux/watchdog.h>
16#include <linux/of_platform.h>
17#include <linux/uaccess.h>
18#include <linux/clk.h>
19#include <linux/io.h>
20
21#include <lantiq_soc.h>
22
23/*
24 * Section 3.4 of the datasheet
25 * 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
44static bool nowayout = WATCHDOG_NOWAYOUT;
45
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{
57 unsigned long int timeout = ltq_wdt_timeout *
58 (ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000;
59 if (timeout > LTQ_MAX_TIMEOUT)
60 timeout = LTQ_MAX_TIMEOUT;
61
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 |
66 LTQ_WDT_PW2 | timeout, ltq_wdt_membase + LTQ_WDT_CR);
67}
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);
74 /*
75 * write the second password magic with no config
76 * 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, <q_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
167 pr_err("watchdog closed without warning\n");
168 ltq_wdt_ok_to_close = 0;
169 clear_bit(0, <q_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 = <q_wdt_fops,
187};
188
189static int __devinit
190ltq_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 }
199
200 ltq_wdt_membase = devm_request_and_ioremap(&pdev->dev, res);
201 if (!ltq_wdt_membase) {
202 dev_err(&pdev->dev, "cannot remap I/O memory region\n");
203 return -ENOMEM;
204 }
205
206 /* we do not need to enable the clock as it is always running */
207 clk = clk_get_io();
208 if (IS_ERR(clk)) {
209 dev_err(&pdev->dev, "Failed to get clock\n");
210 return -ENOENT;
211 }
212 ltq_io_region_clk_rate = clk_get_rate(clk);
213 clk_put(clk);
214
215 /* find out if the watchdog caused the last reboot */
216 if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST)
217 ltq_wdt_bootstatus = WDIOF_CARDRESET;
218
219 dev_info(&pdev->dev, "Init done\n");
220 return misc_register(<q_wdt_miscdev);
221}
222
223static int __devexit
224ltq_wdt_remove(struct platform_device *pdev)
225{
226 misc_deregister(<q_wdt_miscdev);
227
228 return 0;
229}
230
231static const struct of_device_id ltq_wdt_match[] = {
232 { .compatible = "lantiq,wdt" },
233 {},
234};
235MODULE_DEVICE_TABLE(of, ltq_wdt_match);
236
237static struct platform_driver ltq_wdt_driver = {
238 .probe = ltq_wdt_probe,
239 .remove = __devexit_p(ltq_wdt_remove),
240 .driver = {
241 .name = "wdt",
242 .owner = THIS_MODULE,
243 .of_match_table = ltq_wdt_match,
244 },
245};
246
247module_platform_driver(ltq_wdt_driver);
248
249module_param(nowayout, bool, 0);
250MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
251MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
252MODULE_DESCRIPTION("Lantiq SoC Watchdog");
253MODULE_LICENSE("GPL");
254MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * Copyright (C) 2010 John Crispin <john@phrozen.org>
5 * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de>
6 * Based on EP93xx wdt driver
7 */
8
9#include <linux/module.h>
10#include <linux/bitops.h>
11#include <linux/watchdog.h>
12#include <linux/of_platform.h>
13#include <linux/uaccess.h>
14#include <linux/clk.h>
15#include <linux/io.h>
16#include <linux/regmap.h>
17#include <linux/mfd/syscon.h>
18
19#include <lantiq_soc.h>
20
21#define LTQ_XRX_RCU_RST_STAT 0x0014
22#define LTQ_XRX_RCU_RST_STAT_WDT BIT(31)
23
24/* CPU0 Reset Source Register */
25#define LTQ_FALCON_SYS1_CPU0RS 0x0060
26/* reset cause mask */
27#define LTQ_FALCON_SYS1_CPU0RS_MASK 0x0007
28#define LTQ_FALCON_SYS1_CPU0RS_WDT 0x02
29
30/*
31 * Section 3.4 of the datasheet
32 * The password sequence protects the WDT control register from unintended
33 * write actions, which might cause malfunction of the WDT.
34 *
35 * essentially the following two magic passwords need to be written to allow
36 * IO access to the WDT core
37 */
38#define LTQ_WDT_CR_PW1 0x00BE0000
39#define LTQ_WDT_CR_PW2 0x00DC0000
40
41#define LTQ_WDT_CR 0x0 /* watchdog control register */
42#define LTQ_WDT_CR_GEN BIT(31) /* enable bit */
43/* Pre-warning limit set to 1/16 of max WDT period */
44#define LTQ_WDT_CR_PWL (0x3 << 26)
45/* set clock divider to 0x40000 */
46#define LTQ_WDT_CR_CLKDIV (0x3 << 24)
47#define LTQ_WDT_CR_PW_MASK GENMASK(23, 16) /* Password field */
48#define LTQ_WDT_CR_MAX_TIMEOUT ((1 << 16) - 1) /* The reload field is 16 bit */
49#define LTQ_WDT_SR 0x8 /* watchdog status register */
50#define LTQ_WDT_SR_EN BIT(31) /* Enable */
51#define LTQ_WDT_SR_VALUE_MASK GENMASK(15, 0) /* Timer value */
52
53#define LTQ_WDT_DIVIDER 0x40000
54
55static bool nowayout = WATCHDOG_NOWAYOUT;
56
57struct ltq_wdt_hw {
58 int (*bootstatus_get)(struct device *dev);
59};
60
61struct ltq_wdt_priv {
62 struct watchdog_device wdt;
63 void __iomem *membase;
64 unsigned long clk_rate;
65};
66
67static u32 ltq_wdt_r32(struct ltq_wdt_priv *priv, u32 offset)
68{
69 return __raw_readl(priv->membase + offset);
70}
71
72static void ltq_wdt_w32(struct ltq_wdt_priv *priv, u32 val, u32 offset)
73{
74 __raw_writel(val, priv->membase + offset);
75}
76
77static void ltq_wdt_mask(struct ltq_wdt_priv *priv, u32 clear, u32 set,
78 u32 offset)
79{
80 u32 val = ltq_wdt_r32(priv, offset);
81
82 val &= ~(clear);
83 val |= set;
84 ltq_wdt_w32(priv, val, offset);
85}
86
87static struct ltq_wdt_priv *ltq_wdt_get_priv(struct watchdog_device *wdt)
88{
89 return container_of(wdt, struct ltq_wdt_priv, wdt);
90}
91
92static struct watchdog_info ltq_wdt_info = {
93 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
94 WDIOF_CARDRESET,
95 .identity = "ltq_wdt",
96};
97
98static int ltq_wdt_start(struct watchdog_device *wdt)
99{
100 struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt);
101 u32 timeout;
102
103 timeout = wdt->timeout * priv->clk_rate;
104
105 ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR);
106 /* write the second magic plus the configuration and new timeout */
107 ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK | LTQ_WDT_CR_MAX_TIMEOUT,
108 LTQ_WDT_CR_GEN | LTQ_WDT_CR_PWL | LTQ_WDT_CR_CLKDIV |
109 LTQ_WDT_CR_PW2 | timeout,
110 LTQ_WDT_CR);
111
112 return 0;
113}
114
115static int ltq_wdt_stop(struct watchdog_device *wdt)
116{
117 struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt);
118
119 ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR);
120 ltq_wdt_mask(priv, LTQ_WDT_CR_GEN | LTQ_WDT_CR_PW_MASK,
121 LTQ_WDT_CR_PW2, LTQ_WDT_CR);
122
123 return 0;
124}
125
126static int ltq_wdt_ping(struct watchdog_device *wdt)
127{
128 struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt);
129 u32 timeout;
130
131 timeout = wdt->timeout * priv->clk_rate;
132
133 ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK, LTQ_WDT_CR_PW1, LTQ_WDT_CR);
134 /* write the second magic plus the configuration and new timeout */
135 ltq_wdt_mask(priv, LTQ_WDT_CR_PW_MASK | LTQ_WDT_CR_MAX_TIMEOUT,
136 LTQ_WDT_CR_PW2 | timeout, LTQ_WDT_CR);
137
138 return 0;
139}
140
141static unsigned int ltq_wdt_get_timeleft(struct watchdog_device *wdt)
142{
143 struct ltq_wdt_priv *priv = ltq_wdt_get_priv(wdt);
144 u64 timeout;
145
146 timeout = ltq_wdt_r32(priv, LTQ_WDT_SR) & LTQ_WDT_SR_VALUE_MASK;
147 return do_div(timeout, priv->clk_rate);
148}
149
150static const struct watchdog_ops ltq_wdt_ops = {
151 .owner = THIS_MODULE,
152 .start = ltq_wdt_start,
153 .stop = ltq_wdt_stop,
154 .ping = ltq_wdt_ping,
155 .get_timeleft = ltq_wdt_get_timeleft,
156};
157
158static int ltq_wdt_xrx_bootstatus_get(struct device *dev)
159{
160 struct regmap *rcu_regmap;
161 u32 val;
162 int err;
163
164 rcu_regmap = syscon_regmap_lookup_by_phandle(dev->of_node, "regmap");
165 if (IS_ERR(rcu_regmap))
166 return PTR_ERR(rcu_regmap);
167
168 err = regmap_read(rcu_regmap, LTQ_XRX_RCU_RST_STAT, &val);
169 if (err)
170 return err;
171
172 if (val & LTQ_XRX_RCU_RST_STAT_WDT)
173 return WDIOF_CARDRESET;
174
175 return 0;
176}
177
178static int ltq_wdt_falcon_bootstatus_get(struct device *dev)
179{
180 struct regmap *rcu_regmap;
181 u32 val;
182 int err;
183
184 rcu_regmap = syscon_regmap_lookup_by_phandle(dev->of_node,
185 "lantiq,rcu");
186 if (IS_ERR(rcu_regmap))
187 return PTR_ERR(rcu_regmap);
188
189 err = regmap_read(rcu_regmap, LTQ_FALCON_SYS1_CPU0RS, &val);
190 if (err)
191 return err;
192
193 if ((val & LTQ_FALCON_SYS1_CPU0RS_MASK) == LTQ_FALCON_SYS1_CPU0RS_WDT)
194 return WDIOF_CARDRESET;
195
196 return 0;
197}
198
199static int ltq_wdt_probe(struct platform_device *pdev)
200{
201 struct device *dev = &pdev->dev;
202 struct ltq_wdt_priv *priv;
203 struct watchdog_device *wdt;
204 struct clk *clk;
205 const struct ltq_wdt_hw *ltq_wdt_hw;
206 int ret;
207 u32 status;
208
209 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
210 if (!priv)
211 return -ENOMEM;
212
213 priv->membase = devm_platform_ioremap_resource(pdev, 0);
214 if (IS_ERR(priv->membase))
215 return PTR_ERR(priv->membase);
216
217 /* we do not need to enable the clock as it is always running */
218 clk = clk_get_io();
219 priv->clk_rate = clk_get_rate(clk) / LTQ_WDT_DIVIDER;
220 if (!priv->clk_rate) {
221 dev_err(dev, "clock rate less than divider %i\n",
222 LTQ_WDT_DIVIDER);
223 return -EINVAL;
224 }
225
226 wdt = &priv->wdt;
227 wdt->info = <q_wdt_info;
228 wdt->ops = <q_wdt_ops;
229 wdt->min_timeout = 1;
230 wdt->max_timeout = LTQ_WDT_CR_MAX_TIMEOUT / priv->clk_rate;
231 wdt->timeout = wdt->max_timeout;
232 wdt->parent = dev;
233
234 ltq_wdt_hw = of_device_get_match_data(dev);
235 if (ltq_wdt_hw && ltq_wdt_hw->bootstatus_get) {
236 ret = ltq_wdt_hw->bootstatus_get(dev);
237 if (ret >= 0)
238 wdt->bootstatus = ret;
239 }
240
241 watchdog_set_nowayout(wdt, nowayout);
242 watchdog_init_timeout(wdt, 0, dev);
243
244 status = ltq_wdt_r32(priv, LTQ_WDT_SR);
245 if (status & LTQ_WDT_SR_EN) {
246 /*
247 * If the watchdog is already running overwrite it with our
248 * new settings. Stop is not needed as the start call will
249 * replace all settings anyway.
250 */
251 ltq_wdt_start(wdt);
252 set_bit(WDOG_HW_RUNNING, &wdt->status);
253 }
254
255 return devm_watchdog_register_device(dev, wdt);
256}
257
258static const struct ltq_wdt_hw ltq_wdt_xrx100 = {
259 .bootstatus_get = ltq_wdt_xrx_bootstatus_get,
260};
261
262static const struct ltq_wdt_hw ltq_wdt_falcon = {
263 .bootstatus_get = ltq_wdt_falcon_bootstatus_get,
264};
265
266static const struct of_device_id ltq_wdt_match[] = {
267 { .compatible = "lantiq,wdt", .data = NULL },
268 { .compatible = "lantiq,xrx100-wdt", .data = <q_wdt_xrx100 },
269 { .compatible = "lantiq,falcon-wdt", .data = <q_wdt_falcon },
270 {},
271};
272MODULE_DEVICE_TABLE(of, ltq_wdt_match);
273
274static struct platform_driver ltq_wdt_driver = {
275 .probe = ltq_wdt_probe,
276 .driver = {
277 .name = "wdt",
278 .of_match_table = ltq_wdt_match,
279 },
280};
281
282module_platform_driver(ltq_wdt_driver);
283
284module_param(nowayout, bool, 0);
285MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
286MODULE_AUTHOR("John Crispin <john@phrozen.org>");
287MODULE_DESCRIPTION("Lantiq SoC Watchdog");
288MODULE_LICENSE("GPL");