/* * Watchdog timer driver for the WinSystems EBC-C384 * Copyright (C) 2016 William Breathitt Gray * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License, version 2, as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ #include <linux/device.h> #include <linux/dmi.h> #include <linux/errno.h> #include <linux/io.h> #include <linux/ioport.h> #include <linux/isa.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/watchdog.h> #define MODULE_NAME "ebc-c384_wdt" #define WATCHDOG_TIMEOUT 60 /* * The timeout value in minutes must fit in a single byte when sent to the * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. */ #define WATCHDOG_MAX_TIMEOUT 15300 #define BASE_ADDR 0x564 #define ADDR_EXTENT 5 #define CFG_ADDR (BASE_ADDR + 1) #define PET_ADDR (BASE_ADDR + 2) static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static unsigned timeout; module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); static int ebc_c384_wdt_start(struct watchdog_device *wdev) { unsigned t = wdev->timeout; /* resolution is in minutes for timeouts greater than 255 seconds */ if (t > 255) t = DIV_ROUND_UP(t, 60); outb(t, PET_ADDR); return 0; } static int ebc_c384_wdt_stop(struct watchdog_device *wdev) { outb(0x00, PET_ADDR); return 0; } static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) { /* resolution is in minutes for timeouts greater than 255 seconds */ if (t > 255) { /* round second resolution up to minute granularity */ wdev->timeout = roundup(t, 60); /* set watchdog timer for minutes */ outb(0x00, CFG_ADDR); } else { wdev->timeout = t; /* set watchdog timer for seconds */ outb(0x80, CFG_ADDR); } return 0; } static const struct watchdog_ops ebc_c384_wdt_ops = { .start = ebc_c384_wdt_start, .stop = ebc_c384_wdt_stop, .set_timeout = ebc_c384_wdt_set_timeout }; static const struct watchdog_info ebc_c384_wdt_info = { .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, .identity = MODULE_NAME }; static int ebc_c384_wdt_probe(struct device *dev, unsigned int id) { struct watchdog_device *wdd; if (!devm_request_region(dev, BASE_ADDR, ADDR_EXTENT, dev_name(dev))) { dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", BASE_ADDR, BASE_ADDR + ADDR_EXTENT); return -EBUSY; } wdd = devm_kzalloc(dev, sizeof(*wdd), GFP_KERNEL); if (!wdd) return -ENOMEM; wdd->info = &ebc_c384_wdt_info; wdd->ops = &ebc_c384_wdt_ops; wdd->timeout = WATCHDOG_TIMEOUT; wdd->min_timeout = 1; wdd->max_timeout = WATCHDOG_MAX_TIMEOUT; watchdog_set_nowayout(wdd, nowayout); if (watchdog_init_timeout(wdd, timeout, dev)) dev_warn(dev, "Invalid timeout (%u seconds), using default (%u seconds)\n", timeout, WATCHDOG_TIMEOUT); dev_set_drvdata(dev, wdd); return watchdog_register_device(wdd); } static int ebc_c384_wdt_remove(struct device *dev, unsigned int id) { struct watchdog_device *wdd = dev_get_drvdata(dev); watchdog_unregister_device(wdd); return 0; } static struct isa_driver ebc_c384_wdt_driver = { .probe = ebc_c384_wdt_probe, .driver = { .name = MODULE_NAME }, .remove = ebc_c384_wdt_remove }; static int __init ebc_c384_wdt_init(void) { if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) return -ENODEV; return isa_register_driver(&ebc_c384_wdt_driver, 1); } static void __exit ebc_c384_wdt_exit(void) { isa_unregister_driver(&ebc_c384_wdt_driver); } module_init(ebc_c384_wdt_init); module_exit(ebc_c384_wdt_exit); MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("isa:" MODULE_NAME);