Andreas Werner | 5033263 | 2014-08-27 19:52:06 +0200 | [diff] [blame] | 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 | |
| 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 | |
| 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 | |
| 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 |
| 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 | |
| 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 | |
| 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->i2c_client = i2c_client; |
| 134 | |
| 135 | /* |
| 136 | * Get the current wdt timeout value from the BMC because |
| 137 | * the BMC will save the value set before if the system restarts. |
| 138 | */ |
| 139 | bmc_timeout = i2c_smbus_read_word_data(drv_data->i2c_client, |
| 140 | BMC_CMD_WD_TIME); |
| 141 | if (bmc_timeout < 0) { |
| 142 | dev_err(&pdev->dev, "failed to get current WDT timeout\n"); |
| 143 | return bmc_timeout; |
| 144 | } |
| 145 | |
| 146 | watchdog_init_timeout(&drv_data->wdt, bmc_timeout / 10, &pdev->dev); |
| 147 | watchdog_set_nowayout(&drv_data->wdt, nowayout); |
| 148 | watchdog_set_drvdata(&drv_data->wdt, drv_data); |
| 149 | platform_set_drvdata(pdev, drv_data); |
| 150 | |
| 151 | ret = menf21bmc_wdt_set_bootstatus(drv_data); |
| 152 | if (ret < 0) { |
| 153 | dev_err(&pdev->dev, "failed to set Watchdog bootstatus\n"); |
| 154 | return ret; |
| 155 | } |
| 156 | |
| 157 | ret = watchdog_register_device(&drv_data->wdt); |
| 158 | if (ret) { |
| 159 | dev_err(&pdev->dev, "failed to register Watchdog device\n"); |
| 160 | return ret; |
| 161 | } |
| 162 | |
| 163 | dev_info(&pdev->dev, "MEN 14F021P00 BMC Watchdog device enabled\n"); |
| 164 | |
| 165 | return 0; |
| 166 | } |
| 167 | |
| 168 | static int menf21bmc_wdt_remove(struct platform_device *pdev) |
| 169 | { |
| 170 | struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev); |
| 171 | |
| 172 | dev_warn(&pdev->dev, |
| 173 | "Unregister MEN 14F021P00 BMC Watchdog device, board may reset\n"); |
| 174 | |
| 175 | watchdog_unregister_device(&drv_data->wdt); |
| 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
| 180 | static void menf21bmc_wdt_shutdown(struct platform_device *pdev) |
| 181 | { |
| 182 | struct menf21bmc_wdt *drv_data = platform_get_drvdata(pdev); |
| 183 | |
| 184 | i2c_smbus_write_word_data(drv_data->i2c_client, |
| 185 | BMC_CMD_WD_OFF, BMC_WD_OFF_VAL); |
| 186 | } |
| 187 | |
| 188 | static struct platform_driver menf21bmc_wdt = { |
| 189 | .driver = { |
| 190 | .owner = THIS_MODULE, |
| 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"); |