| 1 | /* |
| 2 | * Watchdog timer driver for the WinSystems EBC-C384 |
| 3 | * Copyright (C) 2016 William Breathitt Gray |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License, version 2, as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * This program is distributed in the hope that it will be useful, but |
| 10 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 12 | * General Public License for more details. |
| 13 | */ |
| 14 | #include <linux/device.h> |
| 15 | #include <linux/dmi.h> |
| 16 | #include <linux/errno.h> |
| 17 | #include <linux/io.h> |
| 18 | #include <linux/ioport.h> |
| 19 | #include <linux/kernel.h> |
| 20 | #include <linux/module.h> |
| 21 | #include <linux/moduleparam.h> |
| 22 | #include <linux/platform_device.h> |
| 23 | #include <linux/types.h> |
| 24 | #include <linux/watchdog.h> |
| 25 | |
| 26 | #define MODULE_NAME "ebc-c384_wdt" |
| 27 | #define WATCHDOG_TIMEOUT 60 |
| 28 | /* |
| 29 | * The timeout value in minutes must fit in a single byte when sent to the |
| 30 | * watchdog timer; the maximum timeout possible is 15300 (255 * 60) seconds. |
| 31 | */ |
| 32 | #define WATCHDOG_MAX_TIMEOUT 15300 |
| 33 | #define BASE_ADDR 0x564 |
| 34 | #define ADDR_EXTENT 5 |
| 35 | #define CFG_ADDR (BASE_ADDR + 1) |
| 36 | #define PET_ADDR (BASE_ADDR + 2) |
| 37 | |
| 38 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 39 | module_param(nowayout, bool, 0); |
| 40 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
| 41 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 42 | |
| 43 | static unsigned timeout; |
| 44 | module_param(timeout, uint, 0); |
| 45 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" |
| 46 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
| 47 | |
| 48 | static int ebc_c384_wdt_start(struct watchdog_device *wdev) |
| 49 | { |
| 50 | unsigned t = wdev->timeout; |
| 51 | |
| 52 | /* resolution is in minutes for timeouts greater than 255 seconds */ |
| 53 | if (t > 255) |
| 54 | t = DIV_ROUND_UP(t, 60); |
| 55 | |
| 56 | outb(t, PET_ADDR); |
| 57 | |
| 58 | return 0; |
| 59 | } |
| 60 | |
| 61 | static int ebc_c384_wdt_stop(struct watchdog_device *wdev) |
| 62 | { |
| 63 | outb(0x00, PET_ADDR); |
| 64 | |
| 65 | return 0; |
| 66 | } |
| 67 | |
| 68 | static int ebc_c384_wdt_set_timeout(struct watchdog_device *wdev, unsigned t) |
| 69 | { |
| 70 | /* resolution is in minutes for timeouts greater than 255 seconds */ |
| 71 | if (t > 255) { |
| 72 | /* round second resolution up to minute granularity */ |
| 73 | wdev->timeout = roundup(t, 60); |
| 74 | |
| 75 | /* set watchdog timer for minutes */ |
| 76 | outb(0x00, CFG_ADDR); |
| 77 | } else { |
| 78 | wdev->timeout = t; |
| 79 | |
| 80 | /* set watchdog timer for seconds */ |
| 81 | outb(0x80, CFG_ADDR); |
| 82 | } |
| 83 | |
| 84 | return 0; |
| 85 | } |
| 86 | |
| 87 | static const struct watchdog_ops ebc_c384_wdt_ops = { |
| 88 | .start = ebc_c384_wdt_start, |
| 89 | .stop = ebc_c384_wdt_stop, |
| 90 | .set_timeout = ebc_c384_wdt_set_timeout |
| 91 | }; |
| 92 | |
| 93 | static const struct watchdog_info ebc_c384_wdt_info = { |
| 94 | .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT, |
| 95 | .identity = MODULE_NAME |
| 96 | }; |
| 97 | |
| 98 | static int __init ebc_c384_wdt_probe(struct platform_device *pdev) |
| 99 | { |
| 100 | struct device *dev = &pdev->dev; |
| 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 | platform_set_drvdata(pdev, wdd); |
| 126 | |
| 127 | return watchdog_register_device(wdd); |
| 128 | } |
| 129 | |
| 130 | static int ebc_c384_wdt_remove(struct platform_device *pdev) |
| 131 | { |
| 132 | struct watchdog_device *wdd = platform_get_drvdata(pdev); |
| 133 | |
| 134 | watchdog_unregister_device(wdd); |
| 135 | |
| 136 | return 0; |
| 137 | } |
| 138 | |
| 139 | static struct platform_driver ebc_c384_wdt_driver = { |
| 140 | .driver = { |
| 141 | .name = MODULE_NAME |
| 142 | }, |
| 143 | .remove = ebc_c384_wdt_remove |
| 144 | }; |
| 145 | |
| 146 | static struct platform_device *ebc_c384_wdt_device; |
| 147 | |
| 148 | static int __init ebc_c384_wdt_init(void) |
| 149 | { |
| 150 | int err; |
| 151 | |
| 152 | if (!dmi_match(DMI_BOARD_NAME, "EBC-C384 SBC")) |
| 153 | return -ENODEV; |
| 154 | |
| 155 | ebc_c384_wdt_device = platform_device_alloc(MODULE_NAME, -1); |
| 156 | if (!ebc_c384_wdt_device) |
| 157 | return -ENOMEM; |
| 158 | |
| 159 | err = platform_device_add(ebc_c384_wdt_device); |
| 160 | if (err) |
| 161 | goto err_platform_device; |
| 162 | |
| 163 | err = platform_driver_probe(&ebc_c384_wdt_driver, ebc_c384_wdt_probe); |
| 164 | if (err) |
| 165 | goto err_platform_driver; |
| 166 | |
| 167 | return 0; |
| 168 | |
| 169 | err_platform_driver: |
| 170 | platform_device_del(ebc_c384_wdt_device); |
| 171 | err_platform_device: |
| 172 | platform_device_put(ebc_c384_wdt_device); |
| 173 | return err; |
| 174 | } |
| 175 | |
| 176 | static void __exit ebc_c384_wdt_exit(void) |
| 177 | { |
| 178 | platform_device_unregister(ebc_c384_wdt_device); |
| 179 | platform_driver_unregister(&ebc_c384_wdt_driver); |
| 180 | } |
| 181 | |
| 182 | module_init(ebc_c384_wdt_init); |
| 183 | module_exit(ebc_c384_wdt_exit); |
| 184 | |
| 185 | MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); |
| 186 | MODULE_DESCRIPTION("WinSystems EBC-C384 watchdog timer driver"); |
| 187 | MODULE_LICENSE("GPL v2"); |
| 188 | MODULE_ALIAS("platform:" MODULE_NAME); |