1*6f264047SThomas Richard // SPDX-License-Identifier: GPL-2.0-or-later
2*6f264047SThomas Richard /*
3*6f264047SThomas Richard * Congatec Board Controller watchdog driver
4*6f264047SThomas Richard *
5*6f264047SThomas Richard * Copyright (C) 2024 Bootlin
6*6f264047SThomas Richard * Author: Thomas Richard <thomas.richard@bootlin.com>
7*6f264047SThomas Richard */
8*6f264047SThomas Richard
9*6f264047SThomas Richard #include <linux/build_bug.h>
10*6f264047SThomas Richard #include <linux/device.h>
11*6f264047SThomas Richard #include <linux/limits.h>
12*6f264047SThomas Richard #include <linux/module.h>
13*6f264047SThomas Richard #include <linux/platform_device.h>
14*6f264047SThomas Richard #include <linux/watchdog.h>
15*6f264047SThomas Richard
16*6f264047SThomas Richard #include <linux/mfd/cgbc.h>
17*6f264047SThomas Richard
18*6f264047SThomas Richard #define CGBC_WDT_CMD_TRIGGER 0x27
19*6f264047SThomas Richard #define CGBC_WDT_CMD_INIT 0x28
20*6f264047SThomas Richard #define CGBC_WDT_DISABLE 0x00
21*6f264047SThomas Richard
22*6f264047SThomas Richard #define CGBC_WDT_MODE_SINGLE_EVENT 0x02
23*6f264047SThomas Richard
24*6f264047SThomas Richard #define CGBC_WDT_MIN_TIMEOUT 1
25*6f264047SThomas Richard #define CGBC_WDT_MAX_TIMEOUT ((U32_MAX >> 8) / 1000)
26*6f264047SThomas Richard
27*6f264047SThomas Richard #define CGBC_WDT_DEFAULT_TIMEOUT 30
28*6f264047SThomas Richard #define CGBC_WDT_DEFAULT_PRETIMEOUT 0
29*6f264047SThomas Richard
30*6f264047SThomas Richard enum action {
31*6f264047SThomas Richard ACTION_INT = 0,
32*6f264047SThomas Richard ACTION_SMI,
33*6f264047SThomas Richard ACTION_RESET,
34*6f264047SThomas Richard ACTION_BUTTON,
35*6f264047SThomas Richard };
36*6f264047SThomas Richard
37*6f264047SThomas Richard static unsigned int timeout;
38*6f264047SThomas Richard module_param(timeout, uint, 0);
39*6f264047SThomas Richard MODULE_PARM_DESC(timeout,
40*6f264047SThomas Richard "Watchdog timeout in seconds. (>=0, default="
41*6f264047SThomas Richard __MODULE_STRING(CGBC_WDT_DEFAULT_TIMEOUT) ")");
42*6f264047SThomas Richard
43*6f264047SThomas Richard static unsigned int pretimeout = CGBC_WDT_DEFAULT_PRETIMEOUT;
44*6f264047SThomas Richard module_param(pretimeout, uint, 0);
45*6f264047SThomas Richard MODULE_PARM_DESC(pretimeout,
46*6f264047SThomas Richard "Watchdog pretimeout in seconds. (>=0, default="
47*6f264047SThomas Richard __MODULE_STRING(CGBC_WDT_DEFAULT_PRETIMEOUT) ")");
48*6f264047SThomas Richard
49*6f264047SThomas Richard static bool nowayout = WATCHDOG_NOWAYOUT;
50*6f264047SThomas Richard module_param(nowayout, bool, 0);
51*6f264047SThomas Richard MODULE_PARM_DESC(nowayout,
52*6f264047SThomas Richard "Watchdog cannot be stopped once started (default="
53*6f264047SThomas Richard __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
54*6f264047SThomas Richard
55*6f264047SThomas Richard struct cgbc_wdt_data {
56*6f264047SThomas Richard struct cgbc_device_data *cgbc;
57*6f264047SThomas Richard struct watchdog_device wdd;
58*6f264047SThomas Richard };
59*6f264047SThomas Richard
60*6f264047SThomas Richard struct cgbc_wdt_cmd_cfg {
61*6f264047SThomas Richard u8 cmd;
62*6f264047SThomas Richard u8 mode;
63*6f264047SThomas Richard u8 action;
64*6f264047SThomas Richard u8 timeout1[3];
65*6f264047SThomas Richard u8 timeout2[3];
66*6f264047SThomas Richard u8 reserved[3];
67*6f264047SThomas Richard u8 delay[3];
68*6f264047SThomas Richard } __packed;
69*6f264047SThomas Richard
70*6f264047SThomas Richard static_assert(sizeof(struct cgbc_wdt_cmd_cfg) == 15);
71*6f264047SThomas Richard
cgbc_wdt_start(struct watchdog_device * wdd)72*6f264047SThomas Richard static int cgbc_wdt_start(struct watchdog_device *wdd)
73*6f264047SThomas Richard {
74*6f264047SThomas Richard struct cgbc_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
75*6f264047SThomas Richard struct cgbc_device_data *cgbc = wdt_data->cgbc;
76*6f264047SThomas Richard unsigned int timeout1 = (wdd->timeout - wdd->pretimeout) * 1000;
77*6f264047SThomas Richard unsigned int timeout2 = wdd->pretimeout * 1000;
78*6f264047SThomas Richard u8 action;
79*6f264047SThomas Richard
80*6f264047SThomas Richard struct cgbc_wdt_cmd_cfg cmd_start = {
81*6f264047SThomas Richard .cmd = CGBC_WDT_CMD_INIT,
82*6f264047SThomas Richard .mode = CGBC_WDT_MODE_SINGLE_EVENT,
83*6f264047SThomas Richard .timeout1[0] = (u8)timeout1,
84*6f264047SThomas Richard .timeout1[1] = (u8)(timeout1 >> 8),
85*6f264047SThomas Richard .timeout1[2] = (u8)(timeout1 >> 16),
86*6f264047SThomas Richard .timeout2[0] = (u8)timeout2,
87*6f264047SThomas Richard .timeout2[1] = (u8)(timeout2 >> 8),
88*6f264047SThomas Richard .timeout2[2] = (u8)(timeout2 >> 16),
89*6f264047SThomas Richard };
90*6f264047SThomas Richard
91*6f264047SThomas Richard if (wdd->pretimeout) {
92*6f264047SThomas Richard action = 2;
93*6f264047SThomas Richard action |= ACTION_SMI << 2;
94*6f264047SThomas Richard action |= ACTION_RESET << 4;
95*6f264047SThomas Richard } else {
96*6f264047SThomas Richard action = 1;
97*6f264047SThomas Richard action |= ACTION_RESET << 2;
98*6f264047SThomas Richard }
99*6f264047SThomas Richard
100*6f264047SThomas Richard cmd_start.action = action;
101*6f264047SThomas Richard
102*6f264047SThomas Richard return cgbc_command(cgbc, &cmd_start, sizeof(cmd_start), NULL, 0, NULL);
103*6f264047SThomas Richard }
104*6f264047SThomas Richard
cgbc_wdt_stop(struct watchdog_device * wdd)105*6f264047SThomas Richard static int cgbc_wdt_stop(struct watchdog_device *wdd)
106*6f264047SThomas Richard {
107*6f264047SThomas Richard struct cgbc_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
108*6f264047SThomas Richard struct cgbc_device_data *cgbc = wdt_data->cgbc;
109*6f264047SThomas Richard struct cgbc_wdt_cmd_cfg cmd_stop = {
110*6f264047SThomas Richard .cmd = CGBC_WDT_CMD_INIT,
111*6f264047SThomas Richard .mode = CGBC_WDT_DISABLE,
112*6f264047SThomas Richard };
113*6f264047SThomas Richard
114*6f264047SThomas Richard return cgbc_command(cgbc, &cmd_stop, sizeof(cmd_stop), NULL, 0, NULL);
115*6f264047SThomas Richard }
116*6f264047SThomas Richard
cgbc_wdt_keepalive(struct watchdog_device * wdd)117*6f264047SThomas Richard static int cgbc_wdt_keepalive(struct watchdog_device *wdd)
118*6f264047SThomas Richard {
119*6f264047SThomas Richard struct cgbc_wdt_data *wdt_data = watchdog_get_drvdata(wdd);
120*6f264047SThomas Richard struct cgbc_device_data *cgbc = wdt_data->cgbc;
121*6f264047SThomas Richard u8 cmd_ping = CGBC_WDT_CMD_TRIGGER;
122*6f264047SThomas Richard
123*6f264047SThomas Richard return cgbc_command(cgbc, &cmd_ping, sizeof(cmd_ping), NULL, 0, NULL);
124*6f264047SThomas Richard }
125*6f264047SThomas Richard
cgbc_wdt_set_pretimeout(struct watchdog_device * wdd,unsigned int pretimeout)126*6f264047SThomas Richard static int cgbc_wdt_set_pretimeout(struct watchdog_device *wdd,
127*6f264047SThomas Richard unsigned int pretimeout)
128*6f264047SThomas Richard {
129*6f264047SThomas Richard wdd->pretimeout = pretimeout;
130*6f264047SThomas Richard
131*6f264047SThomas Richard if (watchdog_active(wdd))
132*6f264047SThomas Richard return cgbc_wdt_start(wdd);
133*6f264047SThomas Richard
134*6f264047SThomas Richard return 0;
135*6f264047SThomas Richard }
136*6f264047SThomas Richard
cgbc_wdt_set_timeout(struct watchdog_device * wdd,unsigned int timeout)137*6f264047SThomas Richard static int cgbc_wdt_set_timeout(struct watchdog_device *wdd,
138*6f264047SThomas Richard unsigned int timeout)
139*6f264047SThomas Richard {
140*6f264047SThomas Richard if (timeout < wdd->pretimeout)
141*6f264047SThomas Richard wdd->pretimeout = 0;
142*6f264047SThomas Richard
143*6f264047SThomas Richard wdd->timeout = timeout;
144*6f264047SThomas Richard
145*6f264047SThomas Richard if (watchdog_active(wdd))
146*6f264047SThomas Richard return cgbc_wdt_start(wdd);
147*6f264047SThomas Richard
148*6f264047SThomas Richard return 0;
149*6f264047SThomas Richard }
150*6f264047SThomas Richard
151*6f264047SThomas Richard static const struct watchdog_info cgbc_wdt_info = {
152*6f264047SThomas Richard .identity = "CGBC Watchdog",
153*6f264047SThomas Richard .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
154*6f264047SThomas Richard WDIOF_MAGICCLOSE | WDIOF_PRETIMEOUT
155*6f264047SThomas Richard };
156*6f264047SThomas Richard
157*6f264047SThomas Richard static const struct watchdog_ops cgbc_wdt_ops = {
158*6f264047SThomas Richard .owner = THIS_MODULE,
159*6f264047SThomas Richard .start = cgbc_wdt_start,
160*6f264047SThomas Richard .stop = cgbc_wdt_stop,
161*6f264047SThomas Richard .ping = cgbc_wdt_keepalive,
162*6f264047SThomas Richard .set_timeout = cgbc_wdt_set_timeout,
163*6f264047SThomas Richard .set_pretimeout = cgbc_wdt_set_pretimeout,
164*6f264047SThomas Richard };
165*6f264047SThomas Richard
cgbc_wdt_probe(struct platform_device * pdev)166*6f264047SThomas Richard static int cgbc_wdt_probe(struct platform_device *pdev)
167*6f264047SThomas Richard {
168*6f264047SThomas Richard struct cgbc_device_data *cgbc = dev_get_drvdata(pdev->dev.parent);
169*6f264047SThomas Richard struct device *dev = &pdev->dev;
170*6f264047SThomas Richard struct cgbc_wdt_data *wdt_data;
171*6f264047SThomas Richard struct watchdog_device *wdd;
172*6f264047SThomas Richard
173*6f264047SThomas Richard wdt_data = devm_kzalloc(dev, sizeof(*wdt_data), GFP_KERNEL);
174*6f264047SThomas Richard if (!wdt_data)
175*6f264047SThomas Richard return -ENOMEM;
176*6f264047SThomas Richard
177*6f264047SThomas Richard wdt_data->cgbc = cgbc;
178*6f264047SThomas Richard wdd = &wdt_data->wdd;
179*6f264047SThomas Richard wdd->parent = dev;
180*6f264047SThomas Richard
181*6f264047SThomas Richard wdd->info = &cgbc_wdt_info;
182*6f264047SThomas Richard wdd->ops = &cgbc_wdt_ops;
183*6f264047SThomas Richard wdd->max_timeout = CGBC_WDT_MAX_TIMEOUT;
184*6f264047SThomas Richard wdd->min_timeout = CGBC_WDT_MIN_TIMEOUT;
185*6f264047SThomas Richard
186*6f264047SThomas Richard watchdog_set_drvdata(wdd, wdt_data);
187*6f264047SThomas Richard watchdog_set_nowayout(wdd, nowayout);
188*6f264047SThomas Richard
189*6f264047SThomas Richard wdd->timeout = CGBC_WDT_DEFAULT_TIMEOUT;
190*6f264047SThomas Richard watchdog_init_timeout(wdd, timeout, dev);
191*6f264047SThomas Richard cgbc_wdt_set_pretimeout(wdd, pretimeout);
192*6f264047SThomas Richard
193*6f264047SThomas Richard platform_set_drvdata(pdev, wdt_data);
194*6f264047SThomas Richard watchdog_stop_on_reboot(wdd);
195*6f264047SThomas Richard watchdog_stop_on_unregister(wdd);
196*6f264047SThomas Richard
197*6f264047SThomas Richard return devm_watchdog_register_device(dev, wdd);
198*6f264047SThomas Richard }
199*6f264047SThomas Richard
200*6f264047SThomas Richard static struct platform_driver cgbc_wdt_driver = {
201*6f264047SThomas Richard .driver = {
202*6f264047SThomas Richard .name = "cgbc-wdt",
203*6f264047SThomas Richard },
204*6f264047SThomas Richard .probe = cgbc_wdt_probe,
205*6f264047SThomas Richard };
206*6f264047SThomas Richard
207*6f264047SThomas Richard module_platform_driver(cgbc_wdt_driver);
208*6f264047SThomas Richard
209*6f264047SThomas Richard MODULE_DESCRIPTION("Congatec Board Controller Watchdog Driver");
210*6f264047SThomas Richard MODULE_AUTHOR("Thomas Richard <thomas.richard@bootlin.com>");
211*6f264047SThomas Richard MODULE_LICENSE("GPL");
212