1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Watchdog timer driver for the WinSystems EBC-C384 4 * Copyright (C) 2016 William Breathitt Gray 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License, version 2, as 8 * published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it will be useful, but 11 * WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 * General Public License for more details. 14 */ 15 #include <linux/device.h> 16 #include <linux/dmi.h> 17 #include <linux/errno.h> 18 #include <linux/io.h> 19 #include <linux/ioport.h> 20 #include <linux/isa.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/moduleparam.h> 24 #include <linux/types.h> 25 #include <linux/watchdog.h> 26 27 #define MODULE_NAME "ebc-c384_wdt" 28 #define WATCHDOG_TIMEOUT 60 29 /* 30 * The timeout value in minutes must fit in a single byte when sent to the 31 * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. 32 */ 33 #define WATCHDOG_MAX_TIMEOUT 15300 34 #define BASE_ADDR 0x564 35 #define ADDR_EXTENT 5 36 #define CFG_ADDR (BASE_ADDR + 1) 37 #define PET_ADDR (BASE_ADDR + 2) 38 39 static bool nowayout = WATCHDOG_NOWAYOUT; 40 module_param(nowayout, bool, 0); 41 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 42 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 43 44 static unsigned timeout; 45 module_param(timeout, uint, 0); 46 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" 47 __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 48 49 static int ebc_c384_wdt_start(struct watchdog_device *wdev) 50 { 51 unsigned t = wdev->timeout; 52 53 /* resolution is in minutes for timeouts greater than 255 seconds */ 54 if (t > 255) 55 t = DIV_ROUND_UP(t, 60); 56 57 outb(t, PET_ADDR); 58 59 return 0; 60 } 61 62 static int ebc_c384_wdt_stop(struct watchdog_device *wdev) 63 { 64 outb(0x00, PET_ADDR); 65 66 return 0; 67 } 68 69 static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) 70 { 71 /* resolution is in minutes for timeouts greater than 255 seconds */ 72 if (t > 255) { 73 /* round second resolution up to minute granularity */ 74 wdev->timeout = roundup(t, 60); 75 76 /* set watchdog timer for minutes */ 77 outb(0x00, CFG_ADDR); 78 } else { 79 wdev->timeout = t; 80 81 /* set watchdog timer for seconds */ 82 outb(0x80, CFG_ADDR); 83 } 84 85 return 0; 86 } 87 88 static const struct watchdog_ops ebc_c384_wdt_ops = { 89 .start = ebc_c384_wdt_start, 90 .stop = ebc_c384_wdt_stop, 91 .set_timeout = ebc_c384_wdt_set_timeout 92 }; 93 94 static const struct watchdog_info ebc_c384_wdt_info = { 95 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, 96 .identity = MODULE_NAME 97 }; 98 99 static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) 100 { 101 struct watchdog_device *wdd; 102 103 if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) { 104 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", 105 BASE_ADDR, BASE_ADDR + ADDR_EXTENT); 106 return -EBUSY; 107 } 108 109 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); 110 if (!wdd) 111 return -ENOMEM; 112 113 wdd->info = &ebc_c384_wdt_info; 114 wdd->ops = &ebc_c384_wdt_ops; 115 wdd->timeout = WATCHDOG_TIMEOUT; 116 wdd->min_timeout = 1; 117 wdd->max_timeout = WATCHDOG_MAX_TIMEOUT; 118 119 watchdog_set_nowayout(wdd, nowayout); 120 121 if (watchdog_init_timeout(wdd, timeout, dev)) 122 dev_warn(dev, "Invalid timeout (%u seconds), using default (%u seconds)\n", 123 timeout, WATCHDOG_TIMEOUT); 124 125 return devm_watchdog_register_device(dev, wdd); 126 } 127 128 static struct isa_driver ebc_c384_wdt_driver = { 129 .probe = ebc_c384_wdt_probe, 130 .driver = { 131 .name = MODULE_NAME 132 }, 133 }; 134 135 static int __init ebc_c384_wdt_init(void) 136 { 137 if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) 138 return -ENODEV; 139 140 return isa_register_driver(&ebc_c384_wdt_driver, 1); 141 } 142 143 static void __exit ebc_c384_wdt_exit(void) 144 { 145 isa_unregister_driver(&ebc_c384_wdt_driver); 146 } 147 148 module_init(ebc_c384_wdt_init); 149 module_exit(ebc_c384_wdt_exit); 150 151 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); 152 MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); 153 MODULE_LICENSE("GPL v2"); 154 MODULE_ALIAS("isa:" MODULE_NAME); 155