1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Intel OC Watchdog driver
4 *
5 * Copyright (C) 2025, Siemens
6 * Author: Diogo Ivo <diogo.ivo@siemens.com>
7 */
8
9 #define DRV_NAME "intel_oc_wdt"
10
11 #include <linux/acpi.h>
12 #include <linux/bits.h>
13 #include <linux/io.h>
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/platform_device.h>
17 #include <linux/watchdog.h>
18
19 #define INTEL_OC_WDT_TOV GENMASK(9, 0)
20 #define INTEL_OC_WDT_MIN_TOV 1
21 #define INTEL_OC_WDT_MAX_TOV 1024
22 #define INTEL_OC_WDT_DEF_TOV 60
23
24 /*
25 * One-time writable lock bit. If set forbids
26 * modification of itself, _TOV and _EN until
27 * next reboot.
28 */
29 #define INTEL_OC_WDT_CTL_LCK BIT(12)
30
31 #define INTEL_OC_WDT_EN BIT(14)
32 #define INTEL_OC_WDT_NO_ICCSURV_STS BIT(24)
33 #define INTEL_OC_WDT_ICCSURV_STS BIT(25)
34 #define INTEL_OC_WDT_RLD BIT(31)
35
36 #define INTEL_OC_WDT_STS_BITS (INTEL_OC_WDT_NO_ICCSURV_STS | \
37 INTEL_OC_WDT_ICCSURV_STS)
38
39 #define INTEL_OC_WDT_CTRL_REG(wdt) ((wdt)->ctrl_res->start)
40
41 struct intel_oc_wdt {
42 struct watchdog_device wdd;
43 struct resource *ctrl_res;
44 bool locked;
45 };
46
47 static int heartbeat;
48 module_param(heartbeat, uint, 0);
49 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. (default="
50 __MODULE_STRING(WDT_HEARTBEAT) ")");
51
52 static bool nowayout = WATCHDOG_NOWAYOUT;
53 module_param(nowayout, bool, 0);
54 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
55 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
56
intel_oc_wdt_start(struct watchdog_device * wdd)57 static int intel_oc_wdt_start(struct watchdog_device *wdd)
58 {
59 struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
60
61 if (oc_wdt->locked)
62 return 0;
63
64 outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) | INTEL_OC_WDT_EN,
65 INTEL_OC_WDT_CTRL_REG(oc_wdt));
66
67 return 0;
68 }
69
intel_oc_wdt_stop(struct watchdog_device * wdd)70 static int intel_oc_wdt_stop(struct watchdog_device *wdd)
71 {
72 struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
73
74 outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) & ~INTEL_OC_WDT_EN,
75 INTEL_OC_WDT_CTRL_REG(oc_wdt));
76
77 return 0;
78 }
79
intel_oc_wdt_ping(struct watchdog_device * wdd)80 static int intel_oc_wdt_ping(struct watchdog_device *wdd)
81 {
82 struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
83
84 outl(inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) | INTEL_OC_WDT_RLD,
85 INTEL_OC_WDT_CTRL_REG(oc_wdt));
86
87 return 0;
88 }
89
intel_oc_wdt_set_timeout(struct watchdog_device * wdd,unsigned int t)90 static int intel_oc_wdt_set_timeout(struct watchdog_device *wdd,
91 unsigned int t)
92 {
93 struct intel_oc_wdt *oc_wdt = watchdog_get_drvdata(wdd);
94
95 outl((inl(INTEL_OC_WDT_CTRL_REG(oc_wdt)) & ~INTEL_OC_WDT_TOV) | (t - 1),
96 INTEL_OC_WDT_CTRL_REG(oc_wdt));
97
98 wdd->timeout = t;
99
100 return 0;
101 }
102
103 static const struct watchdog_info intel_oc_wdt_info = {
104 .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
105 .identity = DRV_NAME,
106 };
107
108 static const struct watchdog_ops intel_oc_wdt_ops = {
109 .owner = THIS_MODULE,
110 .start = intel_oc_wdt_start,
111 .stop = intel_oc_wdt_stop,
112 .ping = intel_oc_wdt_ping,
113 .set_timeout = intel_oc_wdt_set_timeout,
114 };
115
intel_oc_wdt_setup(struct intel_oc_wdt * oc_wdt)116 static int intel_oc_wdt_setup(struct intel_oc_wdt *oc_wdt)
117 {
118 struct watchdog_info *info;
119 unsigned long val;
120
121 val = inl(INTEL_OC_WDT_CTRL_REG(oc_wdt));
122
123 if (val & INTEL_OC_WDT_STS_BITS)
124 oc_wdt->wdd.bootstatus |= WDIOF_CARDRESET;
125
126 oc_wdt->locked = !!(val & INTEL_OC_WDT_CTL_LCK);
127
128 if (val & INTEL_OC_WDT_EN) {
129 /*
130 * No need to issue a ping here to "commit" the new timeout
131 * value to hardware as the watchdog core schedules one
132 * immediately when registering the watchdog.
133 */
134 set_bit(WDOG_HW_RUNNING, &oc_wdt->wdd.status);
135
136 if (oc_wdt->locked) {
137 info = (struct watchdog_info *)&intel_oc_wdt_info;
138 /*
139 * Set nowayout unconditionally as we cannot stop
140 * the watchdog.
141 */
142 nowayout = true;
143 /*
144 * If we are locked read the current timeout value
145 * and inform the core we can't change it.
146 */
147 oc_wdt->wdd.timeout = (val & INTEL_OC_WDT_TOV) + 1;
148 info->options &= ~WDIOF_SETTIMEOUT;
149
150 dev_info(oc_wdt->wdd.parent,
151 "Register access locked, heartbeat fixed at: %u s\n",
152 oc_wdt->wdd.timeout);
153 }
154 } else if (oc_wdt->locked) {
155 /*
156 * In case the watchdog is disabled and locked there
157 * is nothing we can do with it so just fail probing.
158 */
159 return -EACCES;
160 }
161
162 val &= ~INTEL_OC_WDT_TOV;
163 outl(val | (oc_wdt->wdd.timeout - 1), INTEL_OC_WDT_CTRL_REG(oc_wdt));
164
165 return 0;
166 }
167
intel_oc_wdt_probe(struct platform_device * pdev)168 static int intel_oc_wdt_probe(struct platform_device *pdev)
169 {
170 struct device *dev = &pdev->dev;
171 struct intel_oc_wdt *oc_wdt;
172 struct watchdog_device *wdd;
173 int ret;
174
175 oc_wdt = devm_kzalloc(&pdev->dev, sizeof(*oc_wdt), GFP_KERNEL);
176 if (!oc_wdt)
177 return -ENOMEM;
178
179 oc_wdt->ctrl_res = platform_get_resource(pdev, IORESOURCE_IO, 0);
180 if (!oc_wdt->ctrl_res) {
181 dev_err(&pdev->dev, "missing I/O resource\n");
182 return -ENODEV;
183 }
184
185 if (!devm_request_region(&pdev->dev, oc_wdt->ctrl_res->start,
186 resource_size(oc_wdt->ctrl_res), pdev->name)) {
187 dev_err(dev, "resource %pR already in use, device disabled\n",
188 oc_wdt->ctrl_res);
189 return -EBUSY;
190 }
191
192 wdd = &oc_wdt->wdd;
193 wdd->min_timeout = INTEL_OC_WDT_MIN_TOV;
194 wdd->max_timeout = INTEL_OC_WDT_MAX_TOV;
195 wdd->timeout = INTEL_OC_WDT_DEF_TOV;
196 wdd->info = &intel_oc_wdt_info;
197 wdd->ops = &intel_oc_wdt_ops;
198 wdd->parent = dev;
199
200 watchdog_init_timeout(wdd, heartbeat, dev);
201
202 ret = intel_oc_wdt_setup(oc_wdt);
203 if (ret)
204 return ret;
205
206 watchdog_set_drvdata(wdd, oc_wdt);
207 watchdog_set_nowayout(wdd, nowayout);
208 watchdog_stop_on_reboot(wdd);
209 watchdog_stop_on_unregister(wdd);
210
211 return devm_watchdog_register_device(dev, wdd);
212 }
213
214 static const struct acpi_device_id intel_oc_wdt_match[] = {
215 { "INT3F0D" },
216 { "INTC1099" },
217 { },
218 };
219 MODULE_DEVICE_TABLE(acpi, intel_oc_wdt_match);
220
221 static struct platform_driver intel_oc_wdt_platform_driver = {
222 .driver = {
223 .name = DRV_NAME,
224 .acpi_match_table = intel_oc_wdt_match,
225 },
226 .probe = intel_oc_wdt_probe,
227 };
228
229 module_platform_driver(intel_oc_wdt_platform_driver);
230
231 MODULE_AUTHOR("Diogo Ivo <diogo.ivo@siemens.com>");
232 MODULE_LICENSE("GPL");
233 MODULE_DESCRIPTION("Intel OC Watchdog driver");
234