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 #include <linux/device.h> 7 #include <linux/dmi.h> 8 #include <linux/errno.h> 9 #include <linux/io.h> 10 #include <linux/ioport.h> 11 #include <linux/isa.h> 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/moduleparam.h> 15 #include <linux/types.h> 16 #include <linux/watchdog.h> 17 18 #define MODULE_NAME "ebc-c384_wdt" 19 #define WATCHDOG_TIMEOUT 60 20 /* 21 * The timeout value in minutes must fit in a single byte when sent to the 22 * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. 23 */ 24 #define WATCHDOG_MAX_TIMEOUT 15300 25 #define BASE_ADDR 0x564 26 #define ADDR_EXTENT 5 27 #define CFG_ADDR (BASE_ADDR + 1) 28 #define PET_ADDR (BASE_ADDR + 2) 29 30 static bool nowayout = WATCHDOG_NOWAYOUT; 31 module_param(nowayout, bool, 0); 32 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" 33 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 34 35 static unsigned timeout; 36 module_param(timeout, uint, 0); 37 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" 38 __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); 39 40 static int ebc_c384_wdt_start(struct watchdog_device *wdev) 41 { 42 unsigned t = wdev->timeout; 43 44 /* resolution is in minutes for timeouts greater than 255 seconds */ 45 if (t > 255) 46 t = DIV_ROUND_UP(t, 60); 47 48 outb(t, PET_ADDR); 49 50 return 0; 51 } 52 53 static int ebc_c384_wdt_stop(struct watchdog_device *wdev) 54 { 55 outb(0x00, PET_ADDR); 56 57 return 0; 58 } 59 60 static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) 61 { 62 /* resolution is in minutes for timeouts greater than 255 seconds */ 63 if (t > 255) { 64 /* round second resolution up to minute granularity */ 65 wdev->timeout = roundup(t, 60); 66 67 /* set watchdog timer for minutes */ 68 outb(0x00, CFG_ADDR); 69 } else { 70 wdev->timeout = t; 71 72 /* set watchdog timer for seconds */ 73 outb(0x80, CFG_ADDR); 74 } 75 76 return 0; 77 } 78 79 static const struct watchdog_ops ebc_c384_wdt_ops = { 80 .start = ebc_c384_wdt_start, 81 .stop = ebc_c384_wdt_stop, 82 .set_timeout = ebc_c384_wdt_set_timeout 83 }; 84 85 static const struct watchdog_info ebc_c384_wdt_info = { 86 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, 87 .identity = MODULE_NAME 88 }; 89 90 static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) 91 { 92 struct watchdog_device *wdd; 93 94 if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) { 95 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", 96 BASE_ADDR, BASE_ADDR + ADDR_EXTENT); 97 return -EBUSY; 98 } 99 100 wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); 101 if (!wdd) 102 return -ENOMEM; 103 104 wdd->info = &ebc_c384_wdt_info; 105 wdd->ops = &ebc_c384_wdt_ops; 106 wdd->timeout = WATCHDOG_TIMEOUT; 107 wdd->min_timeout = 1; 108 wdd->max_timeout = WATCHDOG_MAX_TIMEOUT; 109 110 watchdog_set_nowayout(wdd, nowayout); 111 watchdog_init_timeout(wdd, timeout, dev); 112 113 return devm_watchdog_register_device(dev, wdd); 114 } 115 116 static struct isa_driver ebc_c384_wdt_driver = { 117 .probe = ebc_c384_wdt_probe, 118 .driver = { 119 .name = MODULE_NAME 120 }, 121 }; 122 123 static int __init ebc_c384_wdt_init(void) 124 { 125 if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) 126 return -ENODEV; 127 128 return isa_register_driver(&ebc_c384_wdt_driver, 1); 129 } 130 131 static void __exit ebc_c384_wdt_exit(void) 132 { 133 isa_unregister_driver(&ebc_c384_wdt_driver); 134 } 135 136 module_init(ebc_c384_wdt_init); 137 module_exit(ebc_c384_wdt_exit); 138 139 MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); 140 MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); 141 MODULE_LICENSE("GPL v2"); 142 MODULE_ALIAS("isa:" MODULE_NAME); 143