1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Congatec Board Controller watchdog driver
4 *
5 * Copyright (C) 2024 Bootlin
6 * Author: Thomas Richard <thomas.richard@bootlin.com>
7 */
8
9#include <linux/build_bug.h>
10#include <linux/device.h>
11#include <linux/limits.h>
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/watchdog.h>
15
16#include <linux/mfd/cgbc.h>
17
18#define CGBC_WDT_CMD_TRIGGER 0x27
19#define CGBC_WDT_CMD_INIT 0x28
20#define CGBC_WDT_DISABLE 0x00
21
22#define CGBC_WDT_MODE_SINGLE_EVENT 0x02
23
24#define CGBC_WDT_MIN_TIMEOUT 1
25#define CGBC_WDT_MAX_TIMEOUT ((U32_MAX >> 8) / 1000)
26
27#define CGBC_WDT_DEFAULT_TIMEOUT 30
28#define CGBC_WDT_DEFAULT_PRETIMEOUT 0
29
30enum action {
31 ACTION_INT = 0,
32 ACTION_SMI,
33 ACTION_RESET,
34 ACTION_BUTTON,
35};
36
37static unsigned int timeout;
38module_param(timeout, uint, 0);
39MODULE_PARM_DESC(timeout,
40 "Watchdog timeout in seconds. (>=0, default="
41 __MODULE_STRING(CGBC_WDT_DEFAULT_TIMEOUT) ")");
42
43static unsigned int pretimeout = CGBC_WDT_DEFAULT_PRETIMEOUT;
44module_param(pretimeout, uint, 0);
45MODULE_PARM_DESC(pretimeout,
46 "Watchdog pretimeout in seconds. (>=0, default="
47 __MODULE_STRING(CGBC_WDT_DEFAULT_PRETIMEOUT) ")");
48
49static bool nowayout = WATCHDOG_NOWAYOUT;
50module_param(nowayout, bool, 0);
51MODULE_PARM_DESC(nowayout,
52 "Watchdog cannot be stopped once started (default="
53 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
54
55struct cgbc_wdt_data {
56 struct cgbc_device_data *cgbc;
57 struct watchdog_device wdd;
58};
59
60struct cgbc_wdt_cmd_cfg {
61 u8 cmd;
62 u8 mode;
63 u8 action;
64 u8 timeout1[3];
65 u8 timeout2[3];
66 u8 reserved[3];
67 u8 delay[3];
68} __packed;
69
70static_assert(sizeof(struct cgbc_wdt_cmd_cfg) == 15);
71
72static int cgbc_wdt_start(struct watchdog_device *wdd)
73{
74 struct cgbc_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
75 struct cgbc_device_data *cgbc = wdt_data->cgbc;
76 unsigned int timeout1 = (wdd->timeout - wdd->pretimeout) * 1000;
77 unsigned int timeout2 = wdd->pretimeout * 1000;
78 u8 action;
79
80 struct cgbc_wdt_cmd_cfg cmd_start = {
81 .cmd = CGBC_WDT_CMD_INIT,
82 .mode = CGBC_WDT_MODE_SINGLE_EVENT,
83 .timeout1[0] = (u8)timeout1,
84 .timeout1[1] = (u8)(timeout1 >> 8),
85 .timeout1[2] = (u8)(timeout1 >> 16),
86 .timeout2[0] = (u8)timeout2,
87 .timeout2[1] = (u8)(timeout2 >> 8),
88 .timeout2[2] = (u8)(timeout2 >> 16),
89 };
90
91 if (wdd->pretimeout) {
92 action = 2;
93 action |= ACTION_SMI << 2;
94 action |= ACTION_RESET << 4;
95 } else {
96 action = 1;
97 action |= ACTION_RESET << 2;
98 }
99
100 cmd_start.action = action;
101
102 return cgbc_command(cgbc, cmd: &cmd_start, cmd_size: sizeof(cmd_start), NULL, data_size: 0, NULL);
103}
104
105static int cgbc_wdt_stop(struct watchdog_device *wdd)
106{
107 struct cgbc_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
108 struct cgbc_device_data *cgbc = wdt_data->cgbc;
109 struct cgbc_wdt_cmd_cfg cmd_stop = {
110 .cmd = CGBC_WDT_CMD_INIT,
111 .mode = CGBC_WDT_DISABLE,
112 };
113
114 return cgbc_command(cgbc, cmd: &cmd_stop, cmd_size: sizeof(cmd_stop), NULL, data_size: 0, NULL);
115}
116
117static int cgbc_wdt_keepalive(struct watchdog_device *wdd)
118{
119 struct cgbc_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
120 struct cgbc_device_data *cgbc = wdt_data->cgbc;
121 u8 cmd_ping = CGBC_WDT_CMD_TRIGGER;
122
123 return cgbc_command(cgbc, cmd: &cmd_ping, cmd_size: sizeof(cmd_ping), NULL, data_size: 0, NULL);
124}
125
126static int cgbc_wdt_set_pretimeout(struct watchdog_device *wdd,
127 unsigned int pretimeout)
128{
129 wdd->pretimeout = pretimeout;
130
131 if (watchdog_active(wdd))
132 return cgbc_wdt_start(wdd);
133
134 return 0;
135}
136
137static int cgbc_wdt_set_timeout(struct watchdog_device *wdd,
138 unsigned int timeout)
139{
140 if (timeout < wdd->pretimeout)
141 wdd->pretimeout = 0;
142
143 wdd->timeout = timeout;
144
145 if (watchdog_active(wdd))
146 return cgbc_wdt_start(wdd);
147
148 return 0;
149}
150
151static const struct watchdog_info cgbc_wdt_info = {
152 .identity = "CGBC Watchdog",
153 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
154 WDIOF_MAGICCLOSE | WDIOF_PRETIMEOUT
155};
156
157static const struct watchdog_ops cgbc_wdt_ops = {
158 .owner = THIS_MODULE,
159 .start = cgbc_wdt_start,
160 .stop = cgbc_wdt_stop,
161 .ping = cgbc_wdt_keepalive,
162 .set_timeout = cgbc_wdt_set_timeout,
163 .set_pretimeout = cgbc_wdt_set_pretimeout,
164};
165
166static int cgbc_wdt_probe(struct platform_device *pdev)
167{
168 struct cgbc_device_data *cgbc = dev_get_drvdata(dev: pdev->dev.parent);
169 struct device *dev = &pdev->dev;
170 struct cgbc_wdt_data *wdt_data;
171 struct watchdog_device *wdd;
172
173 wdt_data = devm_kzalloc(dev, size: sizeof(*wdt_data), GFP_KERNEL);
174 if (!wdt_data)
175 return -ENOMEM;
176
177 wdt_data->cgbc = cgbc;
178 wdd = &wdt_data->wdd;
179 wdd->parent = dev;
180
181 wdd->info = &cgbc_wdt_info;
182 wdd->ops = &cgbc_wdt_ops;
183 wdd->max_timeout = CGBC_WDT_MAX_TIMEOUT;
184 wdd->min_timeout = CGBC_WDT_MIN_TIMEOUT;
185
186 watchdog_set_drvdata(wdd, data: wdt_data);
187 watchdog_set_nowayout(wdd, nowayout);
188
189 wdd->timeout = CGBC_WDT_DEFAULT_TIMEOUT;
190 watchdog_init_timeout(wdd, timeout_parm: timeout, dev);
191 cgbc_wdt_set_pretimeout(wdd, pretimeout);
192
193 platform_set_drvdata(pdev, data: wdt_data);
194 watchdog_stop_on_reboot(wdd);
195 watchdog_stop_on_unregister(wdd);
196
197 return devm_watchdog_register_device(dev, wdd);
198}
199
200static struct platform_driver cgbc_wdt_driver = {
201 .driver = {
202 .name = "cgbc-wdt",
203 },
204 .probe = cgbc_wdt_probe,
205};
206
207module_platform_driver(cgbc_wdt_driver);
208
209MODULE_DESCRIPTION("Congatec Board Controller Watchdog Driver");
210MODULE_AUTHOR("Thomas Richard <thomas.richard@bootlin.com>");
211MODULE_LICENSE("GPL");
212

source code of linux/drivers/watchdog/cgbc_wdt.c