1 /*
2 * MEN 14F021P00 Board Management Controller (BMC) Watchdog Driver.
3 *
4 * Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/device.h>
14 #include <linux/module.h>
15 #include <linux/watchdog.h>
16 #include <linux/platform_device.h>
17 #include <linux/i2c.h>
18
19 #define DEVNAME "menf21bmc_wdt"
20
21 #define BMC_CMD_WD_ON 0x11
22 #define BMC_CMD_WD_OFF 0x12
23 #define BMC_CMD_WD_TRIG 0x13
24 #define BMC_CMD_WD_TIME 0x14
25 #define BMC_CMD_WD_STATE 0x17
26 #define BMC_WD_OFF_VAL 0x69
27 #define BMC_CMD_RST_RSN 0x92
28
29 #define BMC_WD_TIMEOUT_MIN 1 /* in sec */
30 #define BMC_WD_TIMEOUT_MAX 6553 /* in sec */
31
32 static bool nowayout = WATCHDOG_NOWAYOUT;
33 module_param(nowayout, bool, 0);
34 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
35 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
36
37 struct menf21bmc_wdt {
38 struct watchdog_device wdt;
39 struct i2c_client *i2c_client;
40 };
41
menf21bmc_wdt_set_bootstatus(struct menf21bmc_wdt * data)42 static int menf21bmc_wdt_set_bootstatus(struct menf21bmc_wdt *data)
43 {
44 int rst_rsn;
45
46 rst_rsn = i2c_smbus_read_byte_data(data->i2c_client, BMC_CMD_RST_RSN);
47 if (rst_rsn < 0)
48 return rst_rsn;
49
50 if (rst_rsn == 0x02)
51 data->wdt.bootstatus |= WDIOF_CARDRESET;
52 else if (rst_rsn == 0x05)
53 data->wdt.bootstatus |= WDIOF_EXTERN1;
54 else if (rst_rsn == 0x06)
55 data->wdt.bootstatus |= WDIOF_EXTERN2;
56 else if (rst_rsn == 0x0A)
57 data->wdt.bootstatus |= WDIOF_POWERUNDER;
58
59 return 0;
60 }
61
menf21bmc_wdt_start(struct watchdog_device * wdt)62 static int menf21bmc_wdt_start(struct watchdog_device *wdt)
63 {
64 struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
65
66 return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_ON);
67 }
68
menf21bmc_wdt_stop(struct watchdog_device * wdt)69 static int menf21bmc_wdt_stop(struct watchdog_device *wdt)
70 {
71 struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
72
73 return i2c_smbus_write_byte_data(drv_data->i2c_client,
74 BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);
75 }
76
77 static int
menf21bmc_wdt_settimeout(struct watchdog_device * wdt,unsigned int timeout)78 menf21bmc_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout)
79 {
80 int ret;
81 struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
82
83 /*
84 * BMC Watchdog does have a resolution of 100ms.
85 * Watchdog API defines the timeout in seconds, so we have to
86 * multiply the value.
87 */
88 ret = i2c_smbus_write_word_data(drv_data->i2c_client,
89 BMC_CMD_WD_TIME, timeout * 10);
90 if (ret < 0)
91 return ret;
92
93 wdt->timeout = timeout;
94
95 return 0;
96 }
97
menf21bmc_wdt_ping(struct watchdog_device * wdt)98 static int menf21bmc_wdt_ping(struct watchdog_device *wdt)
99 {
100 struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdt);
101
102 return i2c_smbus_write_byte(drv_data->i2c_client, BMC_CMD_WD_TRIG);
103 }
104
105 static const struct watchdog_info menf21bmc_wdt_info = {
106 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
107 .identity = DEVNAME,
108 };
109
110 static const struct watchdog_ops menf21bmc_wdt_ops = {
111 .owner = THIS_MODULE,
112 .start = menf21bmc_wdt_start,
113 .stop = menf21bmc_wdt_stop,
114 .ping = menf21bmc_wdt_ping,
115 .set_timeout = menf21bmc_wdt_settimeout,
116 };
117
menf21bmc_wdt_probe(struct platform_device * pdev)118 static int menf21bmc_wdt_probe(struct platform_device *pdev)
119 {
120 int ret, bmc_timeout;
121 struct menf21bmc_wdt *drv_data;
122 struct i2c_client *i2c_client = to_i2c_client(pdev->dev.parent);
123
124 drv_data = devm_kzalloc(&pdev->dev,
125 sizeof(struct menf21bmc_wdt), GFP_KERNEL);
126 if (!drv_data)
127 return -ENOMEM;
128
129 drv_data->wdt.ops = &menf21bmc_wdt_ops;
130 drv_data->wdt.info = &menf21bmc_wdt_info;
131 drv_data->wdt.min_timeout = BMC_WD_TIMEOUT_MIN;
132 drv_data->wdt.max_timeout = BMC_WD_TIMEOUT_MAX;
133 drv_data->wdt.parent = &pdev->dev;
134 drv_data->i2c_client = i2c_client;
135
136 /*
137 * Get the current wdt timeout value from the BMC because
138 * the BMC will save the value set before if the system restarts.
139 */
140 bmc_timeout = i2c_smbus_read_word_data(drv_data->i2c_client,
141 BMC_CMD_WD_TIME);
142 if (bmc_timeout < 0) {
143 dev_err(&pdev->dev, "failed to get current WDT timeout\n");
144 return bmc_timeout;
145 }
146
147 watchdog_init_timeout(&drv_data->wdt, bmc_timeout / 10, &pdev->dev);
148 watchdog_set_nowayout(&drv_data->wdt, nowayout);
149 watchdog_set_drvdata(&drv_data->wdt, drv_data);
150 platform_set_drvdata(pdev, drv_data);
151
152 ret = menf21bmc_wdt_set_bootstatus(drv_data);
153 if (ret < 0) {
154 dev_err(&pdev->dev, "failed to set Watchdog bootstatus\n");
155 return ret;
156 }
157
158 ret = watchdog_register_device(&drv_data->wdt);
159 if (ret) {
160 dev_err(&pdev->dev, "failed to register Watchdog device\n");
161 return ret;
162 }
163
164 dev_info(&pdev->dev, "MEN 14F021P00 BMC Watchdog device enabled\n");
165
166 return 0;
167 }
168
menf21bmc_wdt_remove(struct platform_device * pdev)169 static int menf21bmc_wdt_remove(struct platform_device *pdev)
170 {
171 struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);
172
173 dev_warn(&pdev->dev,
174 "Unregister MEN 14F021P00 BMC Watchdog device, board may reset\n");
175
176 watchdog_unregister_device(&drv_data->wdt);
177
178 return 0;
179 }
180
menf21bmc_wdt_shutdown(struct platform_device * pdev)181 static void menf21bmc_wdt_shutdown(struct platform_device *pdev)
182 {
183 struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev);
184
185 i2c_smbus_write_word_data(drv_data->i2c_client,
186 BMC_CMD_WD_OFF, BMC_WD_OFF_VAL);
187 }
188
189 static struct platform_driver menf21bmc_wdt = {
190 .driver = {
191 .name = DEVNAME,
192 },
193 .probe = menf21bmc_wdt_probe,
194 .remove = menf21bmc_wdt_remove,
195 .shutdown = menf21bmc_wdt_shutdown,
196 };
197
198 module_platform_driver(menf21bmc_wdt);
199
200 MODULE_DESCRIPTION("MEN 14F021P00 BMC Watchdog driver");
201 MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>");
202 MODULE_LICENSE("GPL v2");
203 MODULE_ALIAS("platform:menf21bmc_wdt");
204
