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(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(wdt); 61 62 return i2c_smbus_write_byte(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(wdt); 68 69 return i2c_smbus_write_byte_data(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(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(drv_data->i2c_client, 85 BMC_CMD_WD_TIME, 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(wdt); 97 98 return i2c_smbus_write_byte(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, 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(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(&drv_data->wdt, bmc_timeout / 10, dev); 144 watchdog_set_nowayout(&drv_data->wdt, nowayout); 145 watchdog_set_drvdata(&drv_data->wdt, drv_data); 146 platform_set_drvdata(pdev, drv_data); 147 148 ret = menf21bmc_wdt_set_bootstatus(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(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