1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * MEN 14F021P00 Board Management Controller (BMC) Watchdog Driver. |
4 | * |
5 | * Copyright (C) 2014 MEN Mikro Elektronik Nuernberg GmbH |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/device.h> |
10 | #include <linux/module.h> |
11 | #include <linux/watchdog.h> |
12 | #include <linux/platform_device.h> |
13 | #include <linux/i2c.h> |
14 | |
15 | #define DEVNAME "menf21bmc_wdt" |
16 | |
17 | #define BMC_CMD_WD_ON 0x11 |
18 | #define BMC_CMD_WD_OFF 0x12 |
19 | #define BMC_CMD_WD_TRIG 0x13 |
20 | #define BMC_CMD_WD_TIME 0x14 |
21 | #define BMC_CMD_WD_STATE 0x17 |
22 | #define BMC_WD_OFF_VAL 0x69 |
23 | #define BMC_CMD_RST_RSN 0x92 |
24 | |
25 | #define BMC_WD_TIMEOUT_MIN 1 /* in sec */ |
26 | #define BMC_WD_TIMEOUT_MAX 6553 /* in sec */ |
27 | |
28 | static bool nowayout = WATCHDOG_NOWAYOUT; |
29 | module_param(nowayout, bool, 0); |
30 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
31 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")" ); |
32 | |
33 | struct menf21bmc_wdt { |
34 | struct watchdog_device wdt; |
35 | struct i2c_client *i2c_client; |
36 | }; |
37 | |
38 | static int menf21bmc_wdt_set_bootstatus(struct menf21bmc_wdt *data) |
39 | { |
40 | int rst_rsn; |
41 | |
42 | rst_rsn = i2c_smbus_read_byte_data(client: data->i2c_client, BMC_CMD_RST_RSN); |
43 | if (rst_rsn < 0) |
44 | return rst_rsn; |
45 | |
46 | if (rst_rsn == 0x02) |
47 | data->wdt.bootstatus |= WDIOF_CARDRESET; |
48 | else if (rst_rsn == 0x05) |
49 | data->wdt.bootstatus |= WDIOF_EXTERN1; |
50 | else if (rst_rsn == 0x06) |
51 | data->wdt.bootstatus |= WDIOF_EXTERN2; |
52 | else if (rst_rsn == 0x0A) |
53 | data->wdt.bootstatus |= WDIOF_POWERUNDER; |
54 | |
55 | return 0; |
56 | } |
57 | |
58 | static int menf21bmc_wdt_start(struct watchdog_device *wdt) |
59 | { |
60 | struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdd: wdt); |
61 | |
62 | return i2c_smbus_write_byte(client: drv_data->i2c_client, BMC_CMD_WD_ON); |
63 | } |
64 | |
65 | static int menf21bmc_wdt_stop(struct watchdog_device *wdt) |
66 | { |
67 | struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdd: wdt); |
68 | |
69 | return i2c_smbus_write_byte_data(client: drv_data->i2c_client, |
70 | BMC_CMD_WD_OFF, BMC_WD_OFF_VAL); |
71 | } |
72 | |
73 | static int |
74 | menf21bmc_wdt_settimeout(struct watchdog_device *wdt, unsigned int timeout) |
75 | { |
76 | int ret; |
77 | struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdd: wdt); |
78 | |
79 | /* |
80 | * BMC Watchdog does have a resolution of 100ms. |
81 | * Watchdog API defines the timeout in seconds, so we have to |
82 | * multiply the value. |
83 | */ |
84 | ret = i2c_smbus_write_word_data(client: drv_data->i2c_client, |
85 | BMC_CMD_WD_TIME, value: timeout * 10); |
86 | if (ret < 0) |
87 | return ret; |
88 | |
89 | wdt->timeout = timeout; |
90 | |
91 | return 0; |
92 | } |
93 | |
94 | static int menf21bmc_wdt_ping(struct watchdog_device *wdt) |
95 | { |
96 | struct menf21bmc_wdt *drv_data = watchdog_get_drvdata(wdd: wdt); |
97 | |
98 | return i2c_smbus_write_byte(client: drv_data->i2c_client, BMC_CMD_WD_TRIG); |
99 | } |
100 | |
101 | static const struct watchdog_info menf21bmc_wdt_info = { |
102 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, |
103 | .identity = DEVNAME, |
104 | }; |
105 | |
106 | static const struct watchdog_ops menf21bmc_wdt_ops = { |
107 | .owner = THIS_MODULE, |
108 | .start = menf21bmc_wdt_start, |
109 | .stop = menf21bmc_wdt_stop, |
110 | .ping = menf21bmc_wdt_ping, |
111 | .set_timeout = menf21bmc_wdt_settimeout, |
112 | }; |
113 | |
114 | static int menf21bmc_wdt_probe(struct platform_device *pdev) |
115 | { |
116 | struct device *dev = &pdev->dev; |
117 | int ret, bmc_timeout; |
118 | struct menf21bmc_wdt *drv_data; |
119 | struct i2c_client *i2c_client = to_i2c_client(dev->parent); |
120 | |
121 | drv_data = devm_kzalloc(dev, size: sizeof(struct menf21bmc_wdt), GFP_KERNEL); |
122 | if (!drv_data) |
123 | return -ENOMEM; |
124 | |
125 | drv_data->wdt.ops = &menf21bmc_wdt_ops; |
126 | drv_data->wdt.info = &menf21bmc_wdt_info; |
127 | drv_data->wdt.min_timeout = BMC_WD_TIMEOUT_MIN; |
128 | drv_data->wdt.max_timeout = BMC_WD_TIMEOUT_MAX; |
129 | drv_data->wdt.parent = dev; |
130 | drv_data->i2c_client = i2c_client; |
131 | |
132 | /* |
133 | * Get the current wdt timeout value from the BMC because |
134 | * the BMC will save the value set before if the system restarts. |
135 | */ |
136 | bmc_timeout = i2c_smbus_read_word_data(client: drv_data->i2c_client, |
137 | BMC_CMD_WD_TIME); |
138 | if (bmc_timeout < 0) { |
139 | dev_err(dev, "failed to get current WDT timeout\n" ); |
140 | return bmc_timeout; |
141 | } |
142 | |
143 | watchdog_init_timeout(wdd: &drv_data->wdt, timeout_parm: bmc_timeout / 10, dev); |
144 | watchdog_set_nowayout(wdd: &drv_data->wdt, nowayout); |
145 | watchdog_set_drvdata(wdd: &drv_data->wdt, data: drv_data); |
146 | platform_set_drvdata(pdev, data: drv_data); |
147 | |
148 | ret = menf21bmc_wdt_set_bootstatus(data: drv_data); |
149 | if (ret < 0) { |
150 | dev_err(dev, "failed to set Watchdog bootstatus\n" ); |
151 | return ret; |
152 | } |
153 | |
154 | ret = devm_watchdog_register_device(dev, &drv_data->wdt); |
155 | if (ret) |
156 | return ret; |
157 | |
158 | dev_info(dev, "MEN 14F021P00 BMC Watchdog device enabled\n" ); |
159 | |
160 | return 0; |
161 | } |
162 | |
163 | static void menf21bmc_wdt_shutdown(struct platform_device *pdev) |
164 | { |
165 | struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev); |
166 | |
167 | i2c_smbus_write_word_data(client: drv_data->i2c_client, |
168 | BMC_CMD_WD_OFF, BMC_WD_OFF_VAL); |
169 | } |
170 | |
171 | static struct platform_driver menf21bmc_wdt = { |
172 | .driver = { |
173 | .name = DEVNAME, |
174 | }, |
175 | .probe = menf21bmc_wdt_probe, |
176 | .shutdown = menf21bmc_wdt_shutdown, |
177 | }; |
178 | |
179 | module_platform_driver(menf21bmc_wdt); |
180 | |
181 | MODULE_DESCRIPTION("MEN 14F021P00 BMC Watchdog driver" ); |
182 | MODULE_AUTHOR("Andreas Werner <andreas.werner@men.de>" ); |
183 | MODULE_LICENSE("GPL v2" ); |
184 | MODULE_ALIAS("platform:menf21bmc_wdt" ); |
185 | |