drivers/watchdog/uniphier_wdt.c

   1 /*
   2  * Watchdog driver for the UniPhier watchdog timer
   3  *
   4  * (c) Copyright 2014 Panasonic Corporation
   5  * (c) Copyright 2016 Socionext Inc.
   6  * All rights reserved.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/bitops.h>
  19 #include <linux/mfd/syscon.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/regmap.h>
  24 #include <linux/watchdog.h>
  25
  26 /* WDT timer setting register */
  27 #define WDTTIMSET                       0x3004
  28 #define   WDTTIMSET_PERIOD_MASK         (0xf << 0)
  29 #define   WDTTIMSET_PERIOD_1_SEC        (0x3 << 0)
  30
  31 /* WDT reset selection register */
  32 #define WDTRSTSEL                       0x3008
  33 #define   WDTRSTSEL_RSTSEL_MASK         (0x3 << 0)
  34 #define   WDTRSTSEL_RSTSEL_BOTH         (0x0 << 0)
  35 #define   WDTRSTSEL_RSTSEL_IRQ_ONLY     (0x2 << 0)
  36
  37 /* WDT control register */
  38 #define WDTCTRL                         0x300c
  39 #define   WDTCTRL_STATUS                BIT(8)
  40 #define   WDTCTRL_CLEAR                 BIT(1)
  41 #define   WDTCTRL_ENABLE                BIT(0)
  42
  43 #define SEC_TO_WDTTIMSET_PRD(sec) \
  44                 (ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)
  45
  46 #define WDTST_TIMEOUT                   1000 /* usec */
  47
  48 #define WDT_DEFAULT_TIMEOUT             64   /* Default is 64 seconds */
  49 #define WDT_PERIOD_MIN                  1
  50 #define WDT_PERIOD_MAX                  128
  51
  52 static unsigned int timeout = 0;
  53 static bool nowayout = WATCHDOG_NOWAYOUT;
  54
  55 struct uniphier_wdt_dev {
  56         struct watchdog_device wdt_dev;
  57         struct regmap   *regmap;
  58 };
  59
  60 /*
  61  * UniPhier Watchdog operations
  62  */
  63 static int uniphier_watchdog_ping(struct watchdog_device *w)
  64 {
  65         struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
  66         unsigned int val;
  67         int ret;
  68
  69         /* Clear counter */
  70         ret = regmap_write_bits(wdev->regmap, WDTCTRL,
  71                                 WDTCTRL_CLEAR, WDTCTRL_CLEAR);
  72         if (!ret)
  73                 /*
  74                  * As SoC specification, after clear counter,
  75                  * it needs to wait until counter status is 1.
  76                  */
  77                 ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
  78                                                (val & WDTCTRL_STATUS),
  79                                                0, WDTST_TIMEOUT);
  80
  81         return ret;
  82 }
  83
  84 static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
  85 {
  86         unsigned int val;
  87         int ret;
  88
  89         ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
  90                                        !(val & WDTCTRL_STATUS),
  91                                        0, WDTST_TIMEOUT);
  92         if (ret)
  93                 return ret;
  94
  95         /* Setup period */
  96         ret = regmap_write(regmap, WDTTIMSET,
  97                            SEC_TO_WDTTIMSET_PRD(sec));
  98         if (ret)
  99                 return ret;
 100
 101         /* Enable and clear watchdog */
 102         ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
 103         if (!ret)
 104                 /*
 105                  * As SoC specification, after clear counter,
 106                  * it needs to wait until counter status is 1.
 107                  */
 108                 ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
 109                                                (val & WDTCTRL_STATUS),
 110                                                0, WDTST_TIMEOUT);
 111
 112         return ret;
 113 }
 114
 115 static int __uniphier_watchdog_stop(struct regmap *regmap)
 116 {
 117         /* Disable and stop watchdog */
 118         return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
 119 }
 120
 121 static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
 122 {
 123         int ret;
 124
 125         ret = __uniphier_watchdog_stop(regmap);
 126         if (ret)
 127                 return ret;
 128
 129         return __uniphier_watchdog_start(regmap, sec);
 130 }
 131
 132 static int uniphier_watchdog_start(struct watchdog_device *w)
 133 {
 134         struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
 135         unsigned int tmp_timeout;
 136
 137         tmp_timeout = roundup_pow_of_two(w->timeout);
 138
 139         return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
 140 }
 141
 142 static int uniphier_watchdog_stop(struct watchdog_device *w)
 143 {
 144         struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
 145
 146         return __uniphier_watchdog_stop(wdev->regmap);
 147 }
 148
 149 static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
 150                                          unsigned int t)
 151 {
 152         struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
 153         unsigned int tmp_timeout;
 154         int ret;
 155
 156         tmp_timeout = roundup_pow_of_two(t);
 157         if (tmp_timeout == w->timeout)
 158                 return 0;
 159
 160         if (watchdog_active(w)) {
 161                 ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
 162                 if (ret)
 163                         return ret;
 164         }
 165
 166         w->timeout = tmp_timeout;
 167
 168         return 0;
 169 }
 170
 171 /*
 172  * Kernel Interfaces
 173  */
 174 static const struct watchdog_info uniphier_wdt_info = {
 175         .identity       = "uniphier-wdt",
 176         .options        = WDIOF_SETTIMEOUT |
 177                           WDIOF_KEEPALIVEPING |
 178                           WDIOF_MAGICCLOSE |
 179                           WDIOF_OVERHEAT,
 180 };
 181
 182 static const struct watchdog_ops uniphier_wdt_ops = {
 183         .owner          = THIS_MODULE,
 184         .start          = uniphier_watchdog_start,
 185         .stop           = uniphier_watchdog_stop,
 186         .ping           = uniphier_watchdog_ping,
 187         .set_timeout    = uniphier_watchdog_set_timeout,
 188 };
 189
 190 static int uniphier_wdt_probe(struct platform_device *pdev)
 191 {
 192         struct device *dev = &pdev->dev;
 193         struct uniphier_wdt_dev *wdev;
 194         struct regmap *regmap;
 195         struct device_node *parent;
 196         int ret;
 197
 198         wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
 199         if (!wdev)
 200                 return -ENOMEM;
 201
 202         platform_set_drvdata(pdev, wdev);
 203
 204         parent = of_get_parent(dev->of_node); /* parent should be syscon node */
 205         regmap = syscon_node_to_regmap(parent);
 206         of_node_put(parent);
 207         if (IS_ERR(regmap))
 208                 return PTR_ERR(regmap);
 209
 210         wdev->regmap = regmap;
 211         wdev->wdt_dev.info = &uniphier_wdt_info;
 212         wdev->wdt_dev.ops = &uniphier_wdt_ops;
 213         wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
 214         wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
 215         wdev->wdt_dev.parent = dev;
 216
 217         if (watchdog_init_timeout(&wdev->wdt_dev, timeout, dev) < 0) {
 218                 wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
 219         }
 220         watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
 221         watchdog_stop_on_reboot(&wdev->wdt_dev);
 222
 223         watchdog_set_drvdata(&wdev->wdt_dev, wdev);
 224
 225         uniphier_watchdog_stop(&wdev->wdt_dev);
 226         ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
 227         if (ret)
 228                 return ret;
 229
 230         ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
 231         if (ret)
 232                 return ret;
 233
 234         dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
 235                  wdev->wdt_dev.timeout, nowayout);
 236
 237         return 0;
 238 }
 239
 240 static const struct of_device_id uniphier_wdt_dt_ids[] = {
 241         { .compatible = "socionext,uniphier-wdt" },
 242         { /* sentinel */ }
 243 };
 244 MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);
 245
 246 static struct platform_driver uniphier_wdt_driver = {
 247         .probe          = uniphier_wdt_probe,
 248         .driver         = {
 249                 .name           = "uniphier-wdt",
 250                 .of_match_table = uniphier_wdt_dt_ids,
 251         },
 252 };
 253
 254 module_platform_driver(uniphier_wdt_driver);
 255
 256 module_param(timeout, uint, 0000);
 257 MODULE_PARM_DESC(timeout,
 258         "Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
 259                                 __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
 260
 261 module_param(nowayout, bool, 0000);
 262 MODULE_PARM_DESC(nowayout,
 263         "Watchdog cannot be stopped once started (default="
 264                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 265
 266 MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");
 267 MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
 268 MODULE_LICENSE("GPL v2");