1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright 2024 Google LLC.
4 * Author: Lukasz Majczak <lma@chromium.com>
5 */
6
7#include <linux/err.h>
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/mod_devicetable.h>
11#include <linux/platform_data/cros_ec_commands.h>
12#include <linux/platform_data/cros_ec_proto.h>
13#include <linux/platform_device.h>
14#include <linux/watchdog.h>
15
16#define CROS_EC_WATCHDOG_DEFAULT_TIME	30 /* seconds */
17#define DRV_NAME	"cros-ec-wdt"
18
19union cros_ec_wdt_data {
20	struct ec_params_hang_detect req;
21	struct ec_response_hang_detect resp;
22} __packed;
23
24static int cros_ec_wdt_send_cmd(struct cros_ec_device *cros_ec,
25				union cros_ec_wdt_data *arg)
26{
27	int ret;
28	struct {
29		struct cros_ec_command msg;
30		union cros_ec_wdt_data data;
31	} __packed buf = {
32		.msg = {
33			.version = 0,
34			.command = EC_CMD_HANG_DETECT,
35			.insize  = (arg->req.command == EC_HANG_DETECT_CMD_GET_STATUS) ?
36				   sizeof(struct ec_response_hang_detect) :
37				   0,
38			.outsize = sizeof(struct ec_params_hang_detect),
39		},
40		.data.req = arg->req
41	};
42
43	ret = cros_ec_cmd_xfer_status(cros_ec, &buf.msg);
44	if (ret < 0)
45		return ret;
46
47	arg->resp = buf.data.resp;
48
49	return 0;
50}
51
52static int cros_ec_wdt_ping(struct watchdog_device *wdd)
53{
54	struct cros_ec_device *cros_ec = watchdog_get_drvdata(wdd);
55	union cros_ec_wdt_data arg;
56	int ret;
57
58	arg.req.command = EC_HANG_DETECT_CMD_RELOAD;
59	ret = cros_ec_wdt_send_cmd(cros_ec, &arg);
60	if (ret < 0)
61		dev_dbg(wdd->parent, "Failed to ping watchdog (%d)", ret);
62
63	return ret;
64}
65
66static int cros_ec_wdt_start(struct watchdog_device *wdd)
67{
68	struct cros_ec_device *cros_ec = watchdog_get_drvdata(wdd);
69	union cros_ec_wdt_data arg;
70	int ret;
71
72	/* Prepare watchdog on EC side */
73	arg.req.command = EC_HANG_DETECT_CMD_SET_TIMEOUT;
74	arg.req.reboot_timeout_sec = wdd->timeout;
75	ret = cros_ec_wdt_send_cmd(cros_ec, &arg);
76	if (ret < 0)
77		dev_dbg(wdd->parent, "Failed to start watchdog (%d)", ret);
78
79	return ret;
80}
81
82static int cros_ec_wdt_stop(struct watchdog_device *wdd)
83{
84	struct cros_ec_device *cros_ec = watchdog_get_drvdata(wdd);
85	union cros_ec_wdt_data arg;
86	int ret;
87
88	arg.req.command = EC_HANG_DETECT_CMD_CANCEL;
89	ret = cros_ec_wdt_send_cmd(cros_ec, &arg);
90	if (ret < 0)
91		dev_dbg(wdd->parent, "Failed to stop watchdog (%d)", ret);
92
93	return ret;
94}
95
96static int cros_ec_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
97{
98	unsigned int old_timeout = wdd->timeout;
99	int ret;
100
101	wdd->timeout = t;
102	ret = cros_ec_wdt_start(wdd);
103	if (ret < 0)
104		wdd->timeout = old_timeout;
105
106	return ret;
107}
108
109static const struct watchdog_info cros_ec_wdt_ident = {
110	.options          = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
111	.firmware_version = 0,
112	.identity         = DRV_NAME,
113};
114
115static const struct watchdog_ops cros_ec_wdt_ops = {
116	.owner		 = THIS_MODULE,
117	.ping		 = cros_ec_wdt_ping,
118	.start		 = cros_ec_wdt_start,
119	.stop		 = cros_ec_wdt_stop,
120	.set_timeout = cros_ec_wdt_set_timeout,
121};
122
123static int cros_ec_wdt_probe(struct platform_device *pdev)
124{
125	struct device *dev = &pdev->dev;
126	struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
127	struct cros_ec_device *cros_ec = ec_dev->ec_dev;
128	struct watchdog_device *wdd;
129	union cros_ec_wdt_data arg;
130	int ret = 0;
131
132	wdd = devm_kzalloc(&pdev->dev, sizeof(*wdd), GFP_KERNEL);
133	if (!wdd)
134		return -ENOMEM;
135
136	arg.req.command = EC_HANG_DETECT_CMD_GET_STATUS;
137	ret = cros_ec_wdt_send_cmd(cros_ec, &arg);
138	if (ret < 0)
139		return dev_err_probe(dev, ret, "Failed to get watchdog bootstatus");
140
141	wdd->parent = &pdev->dev;
142	wdd->info = &cros_ec_wdt_ident;
143	wdd->ops = &cros_ec_wdt_ops;
144	wdd->timeout = CROS_EC_WATCHDOG_DEFAULT_TIME;
145	wdd->min_timeout = EC_HANG_DETECT_MIN_TIMEOUT;
146	wdd->max_timeout = EC_HANG_DETECT_MAX_TIMEOUT;
147	if (arg.resp.status == EC_HANG_DETECT_AP_BOOT_EC_WDT)
148		wdd->bootstatus = WDIOF_CARDRESET;
149
150	arg.req.command = EC_HANG_DETECT_CMD_CLEAR_STATUS;
151	ret = cros_ec_wdt_send_cmd(cros_ec, &arg);
152	if (ret < 0)
153		return dev_err_probe(dev, ret, "Failed to clear watchdog bootstatus");
154
155	watchdog_stop_on_reboot(wdd);
156	watchdog_stop_on_unregister(wdd);
157	watchdog_set_drvdata(wdd, cros_ec);
158	platform_set_drvdata(pdev, wdd);
159
160	return devm_watchdog_register_device(dev, wdd);
161}
162
163static int __maybe_unused cros_ec_wdt_suspend(struct platform_device *pdev, pm_message_t state)
164{
165	struct watchdog_device *wdd = platform_get_drvdata(pdev);
166	int ret = 0;
167
168	if (watchdog_active(wdd))
169		ret = cros_ec_wdt_stop(wdd);
170
171	return ret;
172}
173
174static int __maybe_unused cros_ec_wdt_resume(struct platform_device *pdev)
175{
176	struct watchdog_device *wdd = platform_get_drvdata(pdev);
177	int ret = 0;
178
179	if (watchdog_active(wdd))
180		ret = cros_ec_wdt_start(wdd);
181
182	return ret;
183}
184
185static const struct platform_device_id cros_ec_wdt_id[] = {
186	{ DRV_NAME, 0 },
187	{}
188};
189
190static struct platform_driver cros_ec_wdt_driver = {
191	.probe		= cros_ec_wdt_probe,
192	.suspend	= pm_ptr(cros_ec_wdt_suspend),
193	.resume		= pm_ptr(cros_ec_wdt_resume),
194	.driver		= {
195		.name	= DRV_NAME,
196	},
197	.id_table	= cros_ec_wdt_id,
198};
199
200module_platform_driver(cros_ec_wdt_driver);
201
202MODULE_DEVICE_TABLE(platform, cros_ec_wdt_id);
203MODULE_DESCRIPTION("Cros EC Watchdog Device Driver");
204MODULE_LICENSE("GPL");
205