drivers/watchdog/nic7018_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 National Instruments Corp.
   4  */
   5
   6 #include <linux/acpi.h>
   7 #include <linux/bitops.h>
   8 #include <linux/device.h>
   9 #include <linux/io.h>
  10 #include <linux/module.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/watchdog.h>
  13
  14 #define LOCK                    0xA5
  15 #define UNLOCK                  0x5A
  16
  17 #define WDT_CTRL_RESET_EN       BIT(7)
  18 #define WDT_RELOAD_PORT_EN      BIT(7)
  19
  20 #define WDT_CTRL                1
  21 #define WDT_RELOAD_CTRL         2
  22 #define WDT_PRESET_PRESCALE     4
  23 #define WDT_REG_LOCK            5
  24 #define WDT_COUNT               6
  25 #define WDT_RELOAD_PORT         7
  26
  27 #define WDT_MIN_TIMEOUT         1
  28 #define WDT_MAX_TIMEOUT         464
  29 #define WDT_DEFAULT_TIMEOUT     80
  30
  31 #define WDT_MAX_COUNTER         15
  32
  33 static unsigned int timeout;
  34 module_param(timeout, uint, 0);
  35 MODULE_PARM_DESC(timeout,
  36                  "Watchdog timeout in seconds. (default="
  37                  __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
  38
  39 static bool nowayout = WATCHDOG_NOWAYOUT;
  40 module_param(nowayout, bool, 0);
  41 MODULE_PARM_DESC(nowayout,
  42                  "Watchdog cannot be stopped once started. (default="
  43                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  44
  45 struct nic7018_wdt {
  46         u16 io_base;
  47         u32 period;
  48         struct watchdog_device wdd;
  49 };
  50
  51 struct nic7018_config {
  52         u32 period;
  53         u8 divider;
  54 };
  55
  56 static const struct nic7018_config nic7018_configs[] = {
  57         {  2, 4 },
  58         { 32, 5 },
  59 };
  60
  61 static inline u32 nic7018_timeout(u32 period, u8 counter)
  62 {
  63         return period * counter - period / 2;
  64 }
  65
  66 static const struct nic7018_config *nic7018_get_config(u32 timeout,
  67                                                        u8 *counter)
  68 {
  69         const struct nic7018_config *config;
  70         u8 count;
  71
  72         if (timeout < 30 && timeout != 16) {
  73                 config = &nic7018_configs[0];
  74                 count = timeout / 2 + 1;
  75         } else {
  76                 config = &nic7018_configs[1];
  77                 count = DIV_ROUND_UP(timeout + 16, 32);
  78
  79                 if (count > WDT_MAX_COUNTER)
  80                         count = WDT_MAX_COUNTER;
  81         }
  82         *counter = count;
  83         return config;
  84 }
  85
  86 static int nic7018_set_timeout(struct watchdog_device *wdd,
  87                                unsigned int timeout)
  88 {
  89         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
  90         const struct nic7018_config *config;
  91         u8 counter;
  92
  93         config = nic7018_get_config(timeout, &counter);
  94
  95         outb(counter << 4 | config->divider,
  96              wdt->io_base + WDT_PRESET_PRESCALE);
  97
  98         wdd->timeout = nic7018_timeout(config->period, counter);
  99         wdt->period = config->period;
 100
 101         return 0;
 102 }
 103
 104 static int nic7018_start(struct watchdog_device *wdd)
 105 {
 106         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
 107         u8 control;
 108
 109         nic7018_set_timeout(wdd, wdd->timeout);
 110
 111         control = inb(wdt->io_base + WDT_RELOAD_CTRL);
 112         outb(control | WDT_RELOAD_PORT_EN, wdt->io_base + WDT_RELOAD_CTRL);
 113
 114         outb(1, wdt->io_base + WDT_RELOAD_PORT);
 115
 116         control = inb(wdt->io_base + WDT_CTRL);
 117         outb(control | WDT_CTRL_RESET_EN, wdt->io_base + WDT_CTRL);
 118
 119         return 0;
 120 }
 121
 122 static int nic7018_stop(struct watchdog_device *wdd)
 123 {
 124         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
 125
 126         outb(0, wdt->io_base + WDT_CTRL);
 127         outb(0, wdt->io_base + WDT_RELOAD_CTRL);
 128         outb(0xF0, wdt->io_base + WDT_PRESET_PRESCALE);
 129
 130         return 0;
 131 }
 132
 133 static int nic7018_ping(struct watchdog_device *wdd)
 134 {
 135         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
 136
 137         outb(1, wdt->io_base + WDT_RELOAD_PORT);
 138
 139         return 0;
 140 }
 141
 142 static unsigned int nic7018_get_timeleft(struct watchdog_device *wdd)
 143 {
 144         struct nic7018_wdt *wdt = watchdog_get_drvdata(wdd);
 145         u8 count;
 146
 147         count = inb(wdt->io_base + WDT_COUNT) & 0xF;
 148         if (!count)
 149                 return 0;
 150
 151         return nic7018_timeout(wdt->period, count);
 152 }
 153
 154 static const struct watchdog_info nic7018_wdd_info = {
 155         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
 156         .identity = "NIC7018 Watchdog",
 157 };
 158
 159 static const struct watchdog_ops nic7018_wdd_ops = {
 160         .owner = THIS_MODULE,
 161         .start = nic7018_start,
 162         .stop = nic7018_stop,
 163         .ping = nic7018_ping,
 164         .set_timeout = nic7018_set_timeout,
 165         .get_timeleft = nic7018_get_timeleft,
 166 };
 167
 168 static int nic7018_probe(struct platform_device *pdev)
 169 {
 170         struct device *dev = &pdev->dev;
 171         struct watchdog_device *wdd;
 172         struct nic7018_wdt *wdt;
 173         struct resource *io_rc;
 174         int ret;
 175
 176         wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
 177         if (!wdt)
 178                 return -ENOMEM;
 179
 180         platform_set_drvdata(pdev, wdt);
 181
 182         io_rc = platform_get_resource(pdev, IORESOURCE_IO, 0);
 183         if (!io_rc) {
 184                 dev_err(dev, "missing IO resources\n");
 185                 return -EINVAL;
 186         }
 187
 188         if (!devm_request_region(dev, io_rc->start, resource_size(io_rc),
 189                                  KBUILD_MODNAME)) {
 190                 dev_err(dev, "failed to get IO region\n");
 191                 return -EBUSY;
 192         }
 193
 194         wdt->io_base = io_rc->start;
 195         wdd = &wdt->wdd;
 196         wdd->info = &nic7018_wdd_info;
 197         wdd->ops = &nic7018_wdd_ops;
 198         wdd->min_timeout = WDT_MIN_TIMEOUT;
 199         wdd->max_timeout = WDT_MAX_TIMEOUT;
 200         wdd->timeout = WDT_DEFAULT_TIMEOUT;
 201         wdd->parent = dev;
 202
 203         watchdog_set_drvdata(wdd, wdt);
 204         watchdog_set_nowayout(wdd, nowayout);
 205         watchdog_init_timeout(wdd, timeout, dev);
 206
 207         /* Unlock WDT register */
 208         outb(UNLOCK, wdt->io_base + WDT_REG_LOCK);
 209
 210         ret = watchdog_register_device(wdd);
 211         if (ret) {
 212                 outb(LOCK, wdt->io_base + WDT_REG_LOCK);
 213                 return ret;
 214         }
 215
 216         dev_dbg(dev, "io_base=0x%04X, timeout=%d, nowayout=%d\n",
 217                 wdt->io_base, timeout, nowayout);
 218         return 0;
 219 }
 220
 221 static int nic7018_remove(struct platform_device *pdev)
 222 {
 223         struct nic7018_wdt *wdt = platform_get_drvdata(pdev);
 224
 225         watchdog_unregister_device(&wdt->wdd);
 226
 227         /* Lock WDT register */
 228         outb(LOCK, wdt->io_base + WDT_REG_LOCK);
 229
 230         return 0;
 231 }
 232
 233 static const struct acpi_device_id nic7018_device_ids[] = {
 234         {"NIC7018", 0},
 235         {"", 0},
 236 };
 237 MODULE_DEVICE_TABLE(acpi, nic7018_device_ids);
 238
 239 static struct platform_driver watchdog_driver = {
 240         .probe = nic7018_probe,
 241         .remove = nic7018_remove,
 242         .driver = {
 243                 .name = KBUILD_MODNAME,
 244                 .acpi_match_table = ACPI_PTR(nic7018_device_ids),
 245         },
 246 };
 247
 248 module_platform_driver(watchdog_driver);
 249
 250 MODULE_DESCRIPTION("National Instruments NIC7018 Watchdog driver");
 251 MODULE_AUTHOR("Hui Chun Ong <hui.chun.ong@ni.com>");
 252 MODULE_LICENSE("GPL");