drivers/watchdog/nic7018_wdt.c

   1 /*
   2  * Copyright (C) 2016 National Instruments Corp.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/acpi.h>
  16 #include <linux/bitops.h>
  17 #include <linux/device.h>
  18 #include <linux/io.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/watchdog.h>
  22
  23 #define LOCK                    0xA5
  24 #define UNLOCK                  0x5A
  25
  26 #define WDT_CTRL_RESET_EN       BIT(7)
  27 #define WDT_RELOAD_PORT_EN      BIT(7)
  28
  29 #define WDT_CTRL                1
  30 #define WDT_RELOAD_CTRL         2
  31 #define WDT_PRESET_PRESCALE     4
  32 #define WDT_REG_LOCK            5
  33 #define WDT_COUNT               6
  34 #define WDT_RELOAD_PORT         7
  35
  36 #define WDT_MIN_TIMEOUT         1
  37 #define WDT_MAX_TIMEOUT         464
  38 #define WDT_DEFAULT_TIMEOUT     80
  39
  40 #define WDT_MAX_COUNTER         15
  41
  42 static unsigned int timeout;
  43 module_param(timeout, uint, 0);
  44 MODULE_PARM_DESC(timeout,
  45                  "Watchdog timeout in seconds. (default="
  46                  __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
  47
  48 static bool nowayout = WATCHDOG_NOWAYOUT;
  49 module_param(nowayout, bool, 0);
  50 MODULE_PARM_DESC(nowayout,
  51                  "Watchdog cannot be stopped once started. (default="
  52                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  53
  54 struct nic7018_wdt {
  55         u16 io_base;
  56         u32 period;
  57         struct watchdog_device wdd;
  58 };
  59
  60 struct nic7018_config {
  61         u32 period;
  62         u8 divider;
  63 };
  64
  65 static const struct nic7018_config nic7018_configs[] = {
  66         {  2, 4 },
  67         { 32, 5 },
  68 };
  69
  70 static inline u32 nic7018_timeout(u32 period, u8 counter)
  71 {
  72         return period * counter - period / 2;
  73 }
  74
  75 static const struct nic7018_config *nic7018_get_config(u32 timeout,
  76                                                        u8 *counter)
  77 {
  78         const struct nic7018_config *config;
  79         u8 count;
  80
  81         if (timeout < 30 && timeout != 16) {
  82                 config = &nic7018_configs[0];
  83                 count = timeout / 2 + 1;
  84         } else {
  85                 config = &nic7018_configs[1];
  86                 count = DIV_ROUND_UP(timeout + 16, 32);
  87
  88                 if (count > WDT_MAX_COUNTER)
  89                         count = WDT_MAX_COUNTER;
  90         }
  91         *counter = count;
  92         return config;
  93 }
  94
  95 static int nic7018_set_timeout(struct watchdog_device *wdd,
  96                                unsigned int timeout)
  97 {
  98         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
  99         const struct nic7018_config *config;
 100         u8 counter;
 101
 102         config = nic7018_get_config(timeout, &counter);
 103
 104         outb(counter << 4 | config->divider,
 105              wdt->io_base + WDT_PRESET_PRESCALE);
 106
 107         wdd->timeout = nic7018_timeout(config->period, counter);
 108         wdt->period = config->period;
 109
 110         return 0;
 111 }
 112
 113 static int nic7018_start(struct watchdog_device *wdd)
 114 {
 115         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
 116         u8 control;
 117
 118         nic7018_set_timeout(wdd, wdd->timeout);
 119
 120         control = inb(wdt->io_base + WDT_RELOAD_CTRL);
 121         outb(control | WDT_RELOAD_PORT_EN, wdt->io_base + WDT_RELOAD_CTRL);
 122
 123         outb(1, wdt->io_base + WDT_RELOAD_PORT);
 124
 125         control = inb(wdt->io_base + WDT_CTRL);
 126         outb(control | WDT_CTRL_RESET_EN, wdt->io_base + WDT_CTRL);
 127
 128         return 0;
 129 }
 130
 131 static int nic7018_stop(struct watchdog_device *wdd)
 132 {
 133         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
 134
 135         outb(0, wdt->io_base + WDT_CTRL);
 136         outb(0, wdt->io_base + WDT_RELOAD_CTRL);
 137         outb(0xF0, wdt->io_base + WDT_PRESET_PRESCALE);
 138
 139         return 0;
 140 }
 141
 142 static int nic7018_ping(struct watchdog_device *wdd)
 143 {
 144         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
 145
 146         outb(1, wdt->io_base + WDT_RELOAD_PORT);
 147
 148         return 0;
 149 }
 150
 151 static unsigned int nic7018_get_timeleft(struct watchdog_device *wdd)
 152 {
 153         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
 154         u8 count;
 155
 156         count = inb(wdt->io_base + WDT_COUNT) & 0xF;
 157         if (!count)
 158                 return 0;
 159
 160         return nic7018_timeout(wdt->period, count);
 161 }
 162
 163 static const struct watchdog_info nic7018_wdd_info = {
 164         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 165         .identity = "NIC7018 Watchdog",
 166 };
 167
 168 static const struct watchdog_ops nic7018_wdd_ops = {
 169         .owner = THIS_MODULE,
 170         .start = nic7018_start,
 171         .stop = nic7018_stop,
 172         .ping = nic7018_ping,
 173         .set_timeout = nic7018_set_timeout,
 174         .get_timeleft = nic7018_get_timeleft,
 175 };
 176
 177 static int nic7018_probe(struct platform_device *pdev)
 178 {
 179         struct device *dev = &pdev->dev;
 180         struct watchdog_device *wdd;
 181         struct nic7018_wdt *wdt;
 182         struct resource *io_rc;
 183         int ret;
 184
 185         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 186         if (!wdt)
 187                 return -ENOMEM;
 188
 189         platform_set_drvdata(pdev, wdt);
 190
 191         io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
 192         if (!io_rc) {
 193                 dev_err(dev, "missing IO resources\n");
 194                 return -EINVAL;
 195         }
 196
 197         if (!devm_request_region(dev, io_rc->start, resource_size(io_rc),
 198                                  KBUILD_MODNAME)) {
 199                 dev_err(dev, "failed to get IO region\n");
 200                 return -EBUSY;
 201         }
 202
 203         wdt->io_base = io_rc->start;
 204         wdd = &wdt->wdd;
 205         wdd->info = &nic7018_wdd_info;
 206         wdd->ops = &nic7018_wdd_ops;
 207         wdd->min_timeout = WDT_MIN_TIMEOUT;
 208         wdd->max_timeout = WDT_MAX_TIMEOUT;
 209         wdd->timeout = WDT_DEFAULT_TIMEOUT;
 210         wdd->parent = dev;
 211
 212         watchdog_set_drvdata(wdd, wdt);
 213         watchdog_set_nowayout(wdd, nowayout);
 214
 215         ret = watchdog_init_timeout(wdd, timeout, dev);
 216         if (ret)
 217                 dev_warn(dev, "unable to set timeout value, using default\n");
 218
 219         /* Unlock WDT register */
 220         outb(UNLOCK, wdt->io_base + WDT_REG_LOCK);
 221
 222         ret = watchdog_register_device(wdd);
 223         if (ret) {
 224                 outb(LOCK, wdt->io_base + WDT_REG_LOCK);
 225                 dev_err(dev, "failed to register watchdog\n");
 226                 return ret;
 227         }
 228
 229         dev_dbg(dev, "io_base=0x%04X, timeout=%d, nowayout=%d\n",
 230                 wdt->io_base, timeout, nowayout);
 231         return 0;
 232 }
 233
 234 static int nic7018_remove(struct platform_device *pdev)
 235 {
 236         struct nic7018_wdt *wdt = platform_get_drvdata(pdev);
 237
 238         watchdog_unregister_device(&wdt->wdd);
 239
 240         /* Lock WDT register */
 241         outb(LOCK, wdt->io_base + WDT_REG_LOCK);
 242
 243         return 0;
 244 }
 245
 246 static const struct acpi_device_id nic7018_device_ids[] = {
 247         {"NIC7018", 0},
 248         {"", 0},
 249 };
 250 MODULE_DEVICE_TABLE(acpi, nic7018_device_ids);
 251
 252 static struct platform_driver watchdog_driver = {
 253         .probe = nic7018_probe,
 254         .remove = nic7018_remove,
 255         .driver = {
 256                 .name = KBUILD_MODNAME,
 257                 .acpi_match_table = ACPI_PTR(nic7018_device_ids),
 258         },
 259 };
 260
 261 module_platform_driver(watchdog_driver);
 262
 263 MODULE_DESCRIPTION("National Instruments NIC7018 Watchdog driver");
 264 MODULE_AUTHOR("Hui Chun Ong <hui.chun.ong@ni.com>");
 265 MODULE_LICENSE("GPL");