LXR linux/drivers/watchdog/ebc-c384

   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
  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_timeout
  83};
  84
  85static const struct watchdog_info ebc_c384_wdt_info = {
  86        .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT,
  87        .identity = MODULE_NAME
  88};
  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_NAME
 120        },
 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