drivers/watchdog/db8500_wdt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) ST-Ericsson SA 2011-2013
   4  *
   5  * Author: Mathieu Poirier <mathieu.poirier@linaro.org> for ST-Ericsson
   6  * Author: Jonas Aaberg <jonas.aberg@stericsson.com> for ST-Ericsson
   7  */
   8
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/moduleparam.h>
  14 #include <linux/err.h>
  15 #include <linux/uaccess.h>
  16 #include <linux/watchdog.h>
  17 #include <linux/platform_device.h>
  18
  19 #include <linux/mfd/dbx500-prcmu.h>
  20
  21 #define WATCHDOG_TIMEOUT 600 /* 10 minutes */
  22
  23 #define WATCHDOG_MIN    0
  24 #define WATCHDOG_MAX28  268435  /* 28 bit resolution in ms == 268435.455 s */
  25
  26 static unsigned int timeout = WATCHDOG_TIMEOUT;
  27 module_param(timeout, uint, 0);
  28 MODULE_PARM_DESC(timeout,
  29         "Watchdog timeout in seconds. default="
  30                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  31
  32 static bool nowayout = WATCHDOG_NOWAYOUT;
  33 module_param(nowayout, bool, 0);
  34 MODULE_PARM_DESC(nowayout,
  35         "Watchdog cannot be stopped once started (default="
  36                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  37
  38 static int db8500_wdt_start(struct watchdog_device *wdd)
  39 {
  40         return prcmu_enable_a9wdog(PRCMU_WDOG_ALL);
  41 }
  42
  43 static int db8500_wdt_stop(struct watchdog_device *wdd)
  44 {
  45         return prcmu_disable_a9wdog(PRCMU_WDOG_ALL);
  46 }
  47
  48 static int db8500_wdt_keepalive(struct watchdog_device *wdd)
  49 {
  50         return prcmu_kick_a9wdog(PRCMU_WDOG_ALL);
  51 }
  52
  53 static int db8500_wdt_set_timeout(struct watchdog_device *wdd,
  54                                  unsigned int timeout)
  55 {
  56         db8500_wdt_stop(wdd);
  57         prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
  58         db8500_wdt_start(wdd);
  59
  60         return 0;
  61 }
  62
  63 static const struct watchdog_info db8500_wdt_info = {
  64         .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
  65         .identity = "DB8500 WDT",
  66         .firmware_version = 1,
  67 };
  68
  69 static const struct watchdog_ops db8500_wdt_ops = {
  70         .owner = THIS_MODULE,
  71         .start = db8500_wdt_start,
  72         .stop  = db8500_wdt_stop,
  73         .ping  = db8500_wdt_keepalive,
  74         .set_timeout = db8500_wdt_set_timeout,
  75 };
  76
  77 static struct watchdog_device db8500_wdt = {
  78         .info = &db8500_wdt_info,
  79         .ops = &db8500_wdt_ops,
  80         .min_timeout = WATCHDOG_MIN,
  81         .max_timeout = WATCHDOG_MAX28,
  82 };
  83
  84 static int db8500_wdt_probe(struct platform_device *pdev)
  85 {
  86         struct device *dev = &pdev->dev;
  87         int ret;
  88
  89         timeout = 600; /* Default to 10 minutes */
  90         db8500_wdt.parent = dev;
  91         watchdog_set_nowayout(&db8500_wdt, nowayout);
  92
  93         /* disable auto off on sleep */
  94         prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
  95
  96         /* set HW initial value */
  97         prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
  98
  99         ret = devm_watchdog_register_device(dev, &db8500_wdt);
 100         if (ret)
 101                 return ret;
 102
 103         dev_info(dev, "initialized\n");
 104
 105         return 0;
 106 }
 107
 108 #ifdef CONFIG_PM
 109 static int db8500_wdt_suspend(struct platform_device *pdev,
 110                              pm_message_t state)
 111 {
 112         if (watchdog_active(&db8500_wdt)) {
 113                 db8500_wdt_stop(&db8500_wdt);
 114                 prcmu_config_a9wdog(PRCMU_WDOG_CPU1, true);
 115
 116                 prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
 117                 db8500_wdt_start(&db8500_wdt);
 118         }
 119         return 0;
 120 }
 121
 122 static int db8500_wdt_resume(struct platform_device *pdev)
 123 {
 124         if (watchdog_active(&db8500_wdt)) {
 125                 db8500_wdt_stop(&db8500_wdt);
 126                 prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
 127
 128                 prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
 129                 db8500_wdt_start(&db8500_wdt);
 130         }
 131         return 0;
 132 }
 133 #else
 134 #define db8500_wdt_suspend NULL
 135 #define db8500_wdt_resume NULL
 136 #endif
 137
 138 static struct platform_driver db8500_wdt_driver = {
 139         .probe          = db8500_wdt_probe,
 140         .suspend        = db8500_wdt_suspend,
 141         .resume         = db8500_wdt_resume,
 142         .driver         = {
 143                 .name   = "db8500_wdt",
 144         },
 145 };
 146
 147 module_platform_driver(db8500_wdt_driver);
 148
 149 MODULE_AUTHOR("Jonas Aaberg <jonas.aberg@stericsson.com>");
 150 MODULE_DESCRIPTION("DB8500 Watchdog Driver");
 151 MODULE_LICENSE("GPL");
 152 MODULE_ALIAS("platform:db8500_wdt");