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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * drivers/char/watchdog/max63xx_wdt.c
4 *
5 * Driver for max63{69,70,71,72,73,74} watchdog timers
6 *
7 * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
8 *
9 * This driver assumes the watchdog pins are memory mapped (as it is
10 * the case for the Arcom Zeus). Should it be connected over GPIOs or
11 * another interface, some abstraction will have to be introduced.
12 */
13
14#include <linux/err.h>
15#include <linux/module.h>
16#include <linux/moduleparam.h>
17#include <linux/mod_devicetable.h>
18#include <linux/types.h>
19#include <linux/kernel.h>
20#include <linux/watchdog.h>
21#include <linux/bitops.h>
22#include <linux/platform_device.h>
23#include <linux/spinlock.h>
24#include <linux/io.h>
25#include <linux/slab.h>
26#include <linux/property.h>
27
28#define DEFAULT_HEARTBEAT 60
29#define MAX_HEARTBEAT 60
30
31static unsigned int heartbeat = DEFAULT_HEARTBEAT;
32static bool nowayout = WATCHDOG_NOWAYOUT;
33
34/*
35 * Memory mapping: a single byte, 3 first lower bits to select bit 3
36 * to ping the watchdog.
37 */
38#define MAX6369_WDSET (7 << 0)
39#define MAX6369_WDI (1 << 3)
40
41#define MAX6369_WDSET_DISABLED 3
42
43static int nodelay;
44
45struct max63xx_wdt {
46 struct watchdog_device wdd;
47 const struct max63xx_timeout *timeout;
48
49 /* memory mapping */
50 void __iomem *base;
51 spinlock_t lock;
52
53 /* WDI and WSET bits write access routines */
54 void (*ping)(struct max63xx_wdt *wdt);
55 void (*set)(struct max63xx_wdt *wdt, u8 set);
56};
57
58/*
59 * The timeout values used are actually the absolute minimum the chip
60 * offers. Typical values on my board are slightly over twice as long
61 * (10s setting ends up with a 25s timeout), and can be up to 3 times
62 * the nominal setting (according to the datasheet). So please take
63 * these values with a grain of salt. Same goes for the initial delay
64 * "feature". Only max6373/74 have a few settings without this initial
65 * delay (selected with the "nodelay" parameter).
66 *
67 * I also decided to remove from the tables any timeout smaller than a
68 * second, as it looked completly overkill...
69 */
70
71/* Timeouts in second */
72struct max63xx_timeout {
73 const u8 wdset;
74 const u8 tdelay;
75 const u8 twd;
76};
77
78static const struct max63xx_timeout max6369_table[] = {
79 { 5, 1, 1 },
80 { 6, 10, 10 },
81 { 7, 60, 60 },
82 { },
83};
84
85static const struct max63xx_timeout max6371_table[] = {
86 { 6, 60, 3 },
87 { 7, 60, 60 },
88 { },
89};
90
91static const struct max63xx_timeout max6373_table[] = {
92 { 2, 60, 1 },
93 { 5, 0, 1 },
94 { 1, 3, 3 },
95 { 7, 60, 10 },
96 { 6, 0, 10 },
97 { },
98};
99
100static const struct max63xx_timeout *
101max63xx_select_timeout(const struct max63xx_timeout *table, int value)
102{
103 while (table->twd) {
104 if (value <= table->twd) {
105 if (nodelay && table->tdelay == 0)
106 return table;
107
108 if (!nodelay)
109 return table;
110 }
111
112 table++;
113 }
114
115 return NULL;
116}
117
118static int max63xx_wdt_ping(struct watchdog_device *wdd)
119{
120 struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
121
122 wdt->ping(wdt);
123 return 0;
124}
125
126static int max63xx_wdt_start(struct watchdog_device *wdd)
127{
128 struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
129
130 wdt->set(wdt, wdt->timeout->wdset);
131
132 /* check for a edge triggered startup */
133 if (wdt->timeout->tdelay == 0)
134 wdt->ping(wdt);
135 return 0;
136}
137
138static int max63xx_wdt_stop(struct watchdog_device *wdd)
139{
140 struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
141
142 wdt->set(wdt, MAX6369_WDSET_DISABLED);
143 return 0;
144}
145
146static const struct watchdog_ops max63xx_wdt_ops = {
147 .owner = THIS_MODULE,
148 .start = max63xx_wdt_start,
149 .stop = max63xx_wdt_stop,
150 .ping = max63xx_wdt_ping,
151};
152
153static const struct watchdog_info max63xx_wdt_info = {
154 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
155 .identity = "max63xx Watchdog",
156};
157
158static void max63xx_mmap_ping(struct max63xx_wdt *wdt)
159{
160 u8 val;
161
162 spin_lock(&wdt->lock);
163
164 val = __raw_readb(wdt->base);
165
166 __raw_writeb(val | MAX6369_WDI, wdt->base);
167 __raw_writeb(val & ~MAX6369_WDI, wdt->base);
168
169 spin_unlock(&wdt->lock);
170}
171
172static void max63xx_mmap_set(struct max63xx_wdt *wdt, u8 set)
173{
174 u8 val;
175
176 spin_lock(&wdt->lock);
177
178 val = __raw_readb(wdt->base);
179 val &= ~MAX6369_WDSET;
180 val |= set & MAX6369_WDSET;
181 __raw_writeb(val, wdt->base);
182
183 spin_unlock(&wdt->lock);
184}
185
186static int max63xx_mmap_init(struct platform_device *p, struct max63xx_wdt *wdt)
187{
188 wdt->base = devm_platform_ioremap_resource(p, 0);
189 if (IS_ERR(wdt->base))
190 return PTR_ERR(wdt->base);
191
192 spin_lock_init(&wdt->lock);
193
194 wdt->ping = max63xx_mmap_ping;
195 wdt->set = max63xx_mmap_set;
196 return 0;
197}
198
199static int max63xx_wdt_probe(struct platform_device *pdev)
200{
201 struct device *dev = &pdev->dev;
202 struct max63xx_wdt *wdt;
203 const struct max63xx_timeout *table;
204 int err;
205
206 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
207 if (!wdt)
208 return -ENOMEM;
209
210 /* Attempt to use fwnode first */
211 table = device_get_match_data(dev);
212 if (!table)
213 table = (struct max63xx_timeout *)pdev->id_entry->driver_data;
214
215 if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
216 heartbeat = DEFAULT_HEARTBEAT;
217
218 wdt->timeout = max63xx_select_timeout(table, heartbeat);
219 if (!wdt->timeout) {
220 dev_err(dev, "unable to satisfy %ds heartbeat request\n",
221 heartbeat);
222 return -EINVAL;
223 }
224
225 err = max63xx_mmap_init(pdev, wdt);
226 if (err)
227 return err;
228
229 platform_set_drvdata(pdev, &wdt->wdd);
230 watchdog_set_drvdata(&wdt->wdd, wdt);
231
232 wdt->wdd.parent = dev;
233 wdt->wdd.timeout = wdt->timeout->twd;
234 wdt->wdd.info = &max63xx_wdt_info;
235 wdt->wdd.ops = &max63xx_wdt_ops;
236
237 watchdog_set_nowayout(&wdt->wdd, nowayout);
238
239 err = devm_watchdog_register_device(dev, &wdt->wdd);
240 if (err)
241 return err;
242
243 dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
244 wdt->timeout->twd, wdt->timeout->tdelay);
245 return 0;
246}
247
248static const struct platform_device_id max63xx_id_table[] = {
249 { "max6369_wdt", (kernel_ulong_t)max6369_table, },
250 { "max6370_wdt", (kernel_ulong_t)max6369_table, },
251 { "max6371_wdt", (kernel_ulong_t)max6371_table, },
252 { "max6372_wdt", (kernel_ulong_t)max6371_table, },
253 { "max6373_wdt", (kernel_ulong_t)max6373_table, },
254 { "max6374_wdt", (kernel_ulong_t)max6373_table, },
255 { },
256};
257MODULE_DEVICE_TABLE(platform, max63xx_id_table);
258
259static const struct of_device_id max63xx_dt_id_table[] = {
260 { .compatible = "maxim,max6369", .data = max6369_table, },
261 { .compatible = "maxim,max6370", .data = max6369_table, },
262 { .compatible = "maxim,max6371", .data = max6371_table, },
263 { .compatible = "maxim,max6372", .data = max6371_table, },
264 { .compatible = "maxim,max6373", .data = max6373_table, },
265 { .compatible = "maxim,max6374", .data = max6373_table, },
266 { }
267};
268MODULE_DEVICE_TABLE(of, max63xx_dt_id_table);
269
270static struct platform_driver max63xx_wdt_driver = {
271 .probe = max63xx_wdt_probe,
272 .id_table = max63xx_id_table,
273 .driver = {
274 .name = "max63xx_wdt",
275 .of_match_table = max63xx_dt_id_table,
276 },
277};
278
279module_platform_driver(max63xx_wdt_driver);
280
281MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
282MODULE_DESCRIPTION("max63xx Watchdog Driver");
283
284module_param(heartbeat, int, 0);
285MODULE_PARM_DESC(heartbeat,
286 "Watchdog heartbeat period in seconds from 1 to "
287 __MODULE_STRING(MAX_HEARTBEAT) ", default "
288 __MODULE_STRING(DEFAULT_HEARTBEAT));
289
290module_param(nowayout, bool, 0);
291MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
292 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
293
294module_param(nodelay, int, 0);
295MODULE_PARM_DESC(nodelay,
296 "Force selection of a timeout setting without initial delay "
297 "(max6373/74 only, default=0)");
298
299MODULE_LICENSE("GPL v2");
1/*
2 * drivers/char/watchdog/max63xx_wdt.c
3 *
4 * Driver for max63{69,70,71,72,73,74} watchdog timers
5 *
6 * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org>
7 *
8 * This file is licensed under the terms of the GNU General Public
9 * License version 2. This program is licensed "as is" without any
10 * warranty of any kind, whether express or implied.
11 *
12 * This driver assumes the watchdog pins are memory mapped (as it is
13 * the case for the Arcom Zeus). Should it be connected over GPIOs or
14 * another interface, some abstraction will have to be introduced.
15 */
16
17#include <linux/err.h>
18#include <linux/module.h>
19#include <linux/moduleparam.h>
20#include <linux/mod_devicetable.h>
21#include <linux/types.h>
22#include <linux/kernel.h>
23#include <linux/watchdog.h>
24#include <linux/bitops.h>
25#include <linux/platform_device.h>
26#include <linux/spinlock.h>
27#include <linux/io.h>
28#include <linux/slab.h>
29#include <linux/property.h>
30
31#define DEFAULT_HEARTBEAT 60
32#define MAX_HEARTBEAT 60
33
34static unsigned int heartbeat = DEFAULT_HEARTBEAT;
35static bool nowayout = WATCHDOG_NOWAYOUT;
36
37/*
38 * Memory mapping: a single byte, 3 first lower bits to select bit 3
39 * to ping the watchdog.
40 */
41#define MAX6369_WDSET (7 << 0)
42#define MAX6369_WDI (1 << 3)
43
44#define MAX6369_WDSET_DISABLED 3
45
46static int nodelay;
47
48struct max63xx_wdt {
49 struct watchdog_device wdd;
50 const struct max63xx_timeout *timeout;
51
52 /* memory mapping */
53 void __iomem *base;
54 spinlock_t lock;
55
56 /* WDI and WSET bits write access routines */
57 void (*ping)(struct max63xx_wdt *wdt);
58 void (*set)(struct max63xx_wdt *wdt, u8 set);
59};
60
61/*
62 * The timeout values used are actually the absolute minimum the chip
63 * offers. Typical values on my board are slightly over twice as long
64 * (10s setting ends up with a 25s timeout), and can be up to 3 times
65 * the nominal setting (according to the datasheet). So please take
66 * these values with a grain of salt. Same goes for the initial delay
67 * "feature". Only max6373/74 have a few settings without this initial
68 * delay (selected with the "nodelay" parameter).
69 *
70 * I also decided to remove from the tables any timeout smaller than a
71 * second, as it looked completly overkill...
72 */
73
74/* Timeouts in second */
75struct max63xx_timeout {
76 const u8 wdset;
77 const u8 tdelay;
78 const u8 twd;
79};
80
81static const struct max63xx_timeout max6369_table[] = {
82 { 5, 1, 1 },
83 { 6, 10, 10 },
84 { 7, 60, 60 },
85 { },
86};
87
88static const struct max63xx_timeout max6371_table[] = {
89 { 6, 60, 3 },
90 { 7, 60, 60 },
91 { },
92};
93
94static const struct max63xx_timeout max6373_table[] = {
95 { 2, 60, 1 },
96 { 5, 0, 1 },
97 { 1, 3, 3 },
98 { 7, 60, 10 },
99 { 6, 0, 10 },
100 { },
101};
102
103static const struct max63xx_timeout *
104max63xx_select_timeout(const struct max63xx_timeout *table, int value)
105{
106 while (table->twd) {
107 if (value <= table->twd) {
108 if (nodelay && table->tdelay == 0)
109 return table;
110
111 if (!nodelay)
112 return table;
113 }
114
115 table++;
116 }
117
118 return NULL;
119}
120
121static int max63xx_wdt_ping(struct watchdog_device *wdd)
122{
123 struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
124
125 wdt->ping(wdt);
126 return 0;
127}
128
129static int max63xx_wdt_start(struct watchdog_device *wdd)
130{
131 struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
132
133 wdt->set(wdt, wdt->timeout->wdset);
134
135 /* check for a edge triggered startup */
136 if (wdt->timeout->tdelay == 0)
137 wdt->ping(wdt);
138 return 0;
139}
140
141static int max63xx_wdt_stop(struct watchdog_device *wdd)
142{
143 struct max63xx_wdt *wdt = watchdog_get_drvdata(wdd);
144
145 wdt->set(wdt, MAX6369_WDSET_DISABLED);
146 return 0;
147}
148
149static const struct watchdog_ops max63xx_wdt_ops = {
150 .owner = THIS_MODULE,
151 .start = max63xx_wdt_start,
152 .stop = max63xx_wdt_stop,
153 .ping = max63xx_wdt_ping,
154};
155
156static const struct watchdog_info max63xx_wdt_info = {
157 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
158 .identity = "max63xx Watchdog",
159};
160
161static void max63xx_mmap_ping(struct max63xx_wdt *wdt)
162{
163 u8 val;
164
165 spin_lock(&wdt->lock);
166
167 val = __raw_readb(wdt->base);
168
169 __raw_writeb(val | MAX6369_WDI, wdt->base);
170 __raw_writeb(val & ~MAX6369_WDI, wdt->base);
171
172 spin_unlock(&wdt->lock);
173}
174
175static void max63xx_mmap_set(struct max63xx_wdt *wdt, u8 set)
176{
177 u8 val;
178
179 spin_lock(&wdt->lock);
180
181 val = __raw_readb(wdt->base);
182 val &= ~MAX6369_WDSET;
183 val |= set & MAX6369_WDSET;
184 __raw_writeb(val, wdt->base);
185
186 spin_unlock(&wdt->lock);
187}
188
189static int max63xx_mmap_init(struct platform_device *p, struct max63xx_wdt *wdt)
190{
191 wdt->base = devm_platform_ioremap_resource(p, 0);
192 if (IS_ERR(wdt->base))
193 return PTR_ERR(wdt->base);
194
195 spin_lock_init(&wdt->lock);
196
197 wdt->ping = max63xx_mmap_ping;
198 wdt->set = max63xx_mmap_set;
199 return 0;
200}
201
202static int max63xx_wdt_probe(struct platform_device *pdev)
203{
204 struct device *dev = &pdev->dev;
205 struct max63xx_wdt *wdt;
206 const struct max63xx_timeout *table;
207 int err;
208
209 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
210 if (!wdt)
211 return -ENOMEM;
212
213 /* Attempt to use fwnode first */
214 table = device_get_match_data(dev);
215 if (!table)
216 table = (struct max63xx_timeout *)pdev->id_entry->driver_data;
217
218 if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT)
219 heartbeat = DEFAULT_HEARTBEAT;
220
221 wdt->timeout = max63xx_select_timeout(table, heartbeat);
222 if (!wdt->timeout) {
223 dev_err(dev, "unable to satisfy %ds heartbeat request\n",
224 heartbeat);
225 return -EINVAL;
226 }
227
228 err = max63xx_mmap_init(pdev, wdt);
229 if (err)
230 return err;
231
232 platform_set_drvdata(pdev, &wdt->wdd);
233 watchdog_set_drvdata(&wdt->wdd, wdt);
234
235 wdt->wdd.parent = dev;
236 wdt->wdd.timeout = wdt->timeout->twd;
237 wdt->wdd.info = &max63xx_wdt_info;
238 wdt->wdd.ops = &max63xx_wdt_ops;
239
240 watchdog_set_nowayout(&wdt->wdd, nowayout);
241
242 err = devm_watchdog_register_device(dev, &wdt->wdd);
243 if (err)
244 return err;
245
246 dev_info(dev, "using %ds heartbeat with %ds initial delay\n",
247 wdt->timeout->twd, wdt->timeout->tdelay);
248 return 0;
249}
250
251static const struct platform_device_id max63xx_id_table[] = {
252 { "max6369_wdt", (kernel_ulong_t)max6369_table, },
253 { "max6370_wdt", (kernel_ulong_t)max6369_table, },
254 { "max6371_wdt", (kernel_ulong_t)max6371_table, },
255 { "max6372_wdt", (kernel_ulong_t)max6371_table, },
256 { "max6373_wdt", (kernel_ulong_t)max6373_table, },
257 { "max6374_wdt", (kernel_ulong_t)max6373_table, },
258 { },
259};
260MODULE_DEVICE_TABLE(platform, max63xx_id_table);
261
262static const struct of_device_id max63xx_dt_id_table[] = {
263 { .compatible = "maxim,max6369", .data = max6369_table, },
264 { .compatible = "maxim,max6370", .data = max6369_table, },
265 { .compatible = "maxim,max6371", .data = max6371_table, },
266 { .compatible = "maxim,max6372", .data = max6371_table, },
267 { .compatible = "maxim,max6373", .data = max6373_table, },
268 { .compatible = "maxim,max6374", .data = max6373_table, },
269 { }
270};
271MODULE_DEVICE_TABLE(of, max63xx_dt_id_table);
272
273static struct platform_driver max63xx_wdt_driver = {
274 .probe = max63xx_wdt_probe,
275 .id_table = max63xx_id_table,
276 .driver = {
277 .name = "max63xx_wdt",
278 .of_match_table = max63xx_dt_id_table,
279 },
280};
281
282module_platform_driver(max63xx_wdt_driver);
283
284MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>");
285MODULE_DESCRIPTION("max63xx Watchdog Driver");
286
287module_param(heartbeat, int, 0);
288MODULE_PARM_DESC(heartbeat,
289 "Watchdog heartbeat period in seconds from 1 to "
290 __MODULE_STRING(MAX_HEARTBEAT) ", default "
291 __MODULE_STRING(DEFAULT_HEARTBEAT));
292
293module_param(nowayout, bool, 0);
294MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
295 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
296
297module_param(nodelay, int, 0);
298MODULE_PARM_DESC(nodelay,
299 "Force selection of a timeout setting without initial delay "
300 "(max6373/74 only, default=0)");
301
302MODULE_LICENSE("GPL v2");