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1// SPDX-License-Identifier: GPL-2.02/*3 * Watchdog timer driver for the WinSystems EBC-C3844 * Copyright (C) 2016 William Breathitt Gray5 */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 6020/*21 * The timeout value in minutes must fit in a single byte when sent to the22 * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds.23 */24#define WATCHDOG_MAX_TIMEOUT 1530025#define BASE_ADDR 0x56426#define ADDR_EXTENT 527#define CFG_ADDR (BASE_ADDR + 1)28#define PET_ADDR (BASE_ADDR + 2)29 30static bool nowayout = WATCHDOG_NOWAYOUT;31module_param(nowayout, bool, 0);32MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="33 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");34 35static unsigned timeout;36module_param(timeout, uint, 0);37MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="38 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");39 40static 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 53static int ebc_c384_wdt_stop(struct watchdog_device *wdev)54{55 outb(0x00, PET_ADDR);56 57 return 0;58}59 60static 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 79static 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_timeout83};84 85static const struct watchdog_info ebc_c384_wdt_info = {86 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT,87 .identity = MODULE_NAME88};89 90static 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 116static struct isa_driver ebc_c384_wdt_driver = {117 .probe = ebc_c384_wdt_probe,118 .driver = {119 .name = MODULE_NAME120 },121};122 123static 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 131static void __exit ebc_c384_wdt_exit(void)132{133 isa_unregister_driver(&ebc_c384_wdt_driver);134}135 136module_init(ebc_c384_wdt_init);137module_exit(ebc_c384_wdt_exit);138 139MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");140MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver");141MODULE_LICENSE("GPL v2");142MODULE_ALIAS("isa:" MODULE_NAME);143