drivers/watchdog/ux500_wdt.c

   1 /*
   2  * Copyright (C) ST-Ericsson SA 2011-2013
   3  *
   4  * License Terms: GNU General Public License v2
   5  *
   6  * Author: Mathieu Poirier <mathieu.poirier@linaro.org> for ST-Ericsson
   7  * Author: Jonas Aaberg <jonas.aberg@stericsson.com> for ST-Ericsson
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/moduleparam.h>
  15 #include <linux/miscdevice.h>
  16 #include <linux/err.h>
  17 #include <linux/uaccess.h>
  18 #include <linux/watchdog.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/platform_data/ux500_wdt.h>
  21
  22 #include <linux/mfd/dbx500-prcmu.h>
  23
  24 #define WATCHDOG_TIMEOUT 600 /* 10 minutes */
  25
  26 #define WATCHDOG_MIN    0
  27 #define WATCHDOG_MAX28  268435  /* 28 bit resolution in ms == 268435.455 s */
  28 #define WATCHDOG_MAX32  4294967 /* 32 bit resolution in ms == 4294967.295 s */
  29
  30 static unsigned int timeout = WATCHDOG_TIMEOUT;
  31 module_param(timeout, uint, 0);
  32 MODULE_PARM_DESC(timeout,
  33         "Watchdog timeout in seconds. default="
  34                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  35
  36 static bool nowayout = WATCHDOG_NOWAYOUT;
  37 module_param(nowayout, bool, 0);
  38 MODULE_PARM_DESC(nowayout,
  39         "Watchdog cannot be stopped once started (default="
  40                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  41
  42 static int ux500_wdt_start(struct watchdog_device *wdd)
  43 {
  44         return prcmu_enable_a9wdog(PRCMU_WDOG_ALL);
  45 }
  46
  47 static int ux500_wdt_stop(struct watchdog_device *wdd)
  48 {
  49         return prcmu_disable_a9wdog(PRCMU_WDOG_ALL);
  50 }
  51
  52 static int ux500_wdt_keepalive(struct watchdog_device *wdd)
  53 {
  54         return prcmu_kick_a9wdog(PRCMU_WDOG_ALL);
  55 }
  56
  57 static int ux500_wdt_set_timeout(struct watchdog_device *wdd,
  58                                  unsigned int timeout)
  59 {
  60         ux500_wdt_stop(wdd);
  61         prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
  62         ux500_wdt_start(wdd);
  63
  64         return 0;
  65 }
  66
  67 static const struct watchdog_info ux500_wdt_info = {
  68         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
  69         .identity = "Ux500 WDT",
  70         .firmware_version = 1,
  71 };
  72
  73 static const struct watchdog_ops ux500_wdt_ops = {
  74         .owner = THIS_MODULE,
  75         .start = ux500_wdt_start,
  76         .stop  = ux500_wdt_stop,
  77         .ping  = ux500_wdt_keepalive,
  78         .set_timeout = ux500_wdt_set_timeout,
  79 };
  80
  81 static struct watchdog_device ux500_wdt = {
  82         .info = &ux500_wdt_info,
  83         .ops = &ux500_wdt_ops,
  84         .min_timeout = WATCHDOG_MIN,
  85         .max_timeout = WATCHDOG_MAX32,
  86 };
  87
  88 static int ux500_wdt_probe(struct platform_device *pdev)
  89 {
  90         int ret;
  91         struct ux500_wdt_data *pdata = pdev->dev.platform_data;
  92
  93         if (pdata) {
  94                 if (pdata->timeout > 0)
  95                         timeout = pdata->timeout;
  96                 if (pdata->has_28_bits_resolution)
  97                         ux500_wdt.max_timeout = WATCHDOG_MAX28;
  98         }
  99
 100         watchdog_set_nowayout(&ux500_wdt, nowayout);
 101
 102         /* disable auto off on sleep */
 103         prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
 104
 105         /* set HW initial value */
 106         prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
 107
 108         ret = watchdog_register_device(&ux500_wdt);
 109         if (ret)
 110                 return ret;
 111
 112         dev_info(&pdev->dev, "initialized\n");
 113
 114         return 0;
 115 }
 116
 117 static int ux500_wdt_remove(struct platform_device *dev)
 118 {
 119         watchdog_unregister_device(&ux500_wdt);
 120
 121         return 0;
 122 }
 123
 124 #ifdef CONFIG_PM
 125 static int ux500_wdt_suspend(struct platform_device *pdev,
 126                              pm_message_t state)
 127 {
 128         if (watchdog_active(&ux500_wdt)) {
 129                 ux500_wdt_stop(&ux500_wdt);
 130                 prcmu_config_a9wdog(PRCMU_WDOG_CPU1, true);
 131
 132                 prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
 133                 ux500_wdt_start(&ux500_wdt);
 134         }
 135         return 0;
 136 }
 137
 138 static int ux500_wdt_resume(struct platform_device *pdev)
 139 {
 140         if (watchdog_active(&ux500_wdt)) {
 141                 ux500_wdt_stop(&ux500_wdt);
 142                 prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
 143
 144                 prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
 145                 ux500_wdt_start(&ux500_wdt);
 146         }
 147         return 0;
 148 }
 149 #else
 150 #define ux500_wdt_suspend NULL
 151 #define ux500_wdt_resume NULL
 152 #endif
 153
 154 static struct platform_driver ux500_wdt_driver = {
 155         .probe          = ux500_wdt_probe,
 156         .remove         = ux500_wdt_remove,
 157         .suspend        = ux500_wdt_suspend,
 158         .resume         = ux500_wdt_resume,
 159         .driver         = {
 160                 .owner  = THIS_MODULE,
 161                 .name   = "ux500_wdt",
 162         },
 163 };
 164
 165 module_platform_driver(ux500_wdt_driver);
 166
 167 MODULE_AUTHOR("Jonas Aaberg <jonas.aberg@stericsson.com>");
 168 MODULE_DESCRIPTION("Ux500 Watchdog Driver");
 169 MODULE_LICENSE("GPL");
 170 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 171 MODULE_ALIAS("platform:ux500_wdt");