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