linux/drivers/watchdog/ux500_wdt.c
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   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
  30static unsigned int timeout = WATCHDOG_TIMEOUT;
  31module_param(timeout, uint, 0);
  32MODULE_PARM_DESC(timeout,
  33        "Watchdog timeout in seconds. default="
  34                                __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  35
  36static bool nowayout = WATCHDOG_NOWAYOUT;
  37module_param(nowayout, bool, 0);
  38MODULE_PARM_DESC(nowayout,
  39        "Watchdog cannot be stopped once started (default="
  40                                __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  41
  42static int ux500_wdt_start(struct watchdog_device *wdd)
  43{
  44        return prcmu_enable_a9wdog(PRCMU_WDOG_ALL);
  45}
  46
  47static int ux500_wdt_stop(struct watchdog_device *wdd)
  48{
  49        return prcmu_disable_a9wdog(PRCMU_WDOG_ALL);
  50}
  51
  52static int ux500_wdt_keepalive(struct watchdog_device *wdd)
  53{
  54        return prcmu_kick_a9wdog(PRCMU_WDOG_ALL);
  55}
  56
  57static 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
  67static 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
  73static 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
  81static 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
  88static 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
 117static 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
 125static 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
 138static 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
 154static 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
 165module_platform_driver(ux500_wdt_driver);
 166
 167MODULE_AUTHOR("Jonas Aaberg <jonas.aberg@stericsson.com>");
 168MODULE_DESCRIPTION("Ux500 Watchdog Driver");
 169MODULE_LICENSE("GPL");
 170MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 171MODULE_ALIAS("platform:ux500_wdt");
 172
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