drivers/watchdog/db8500_wdt.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (C) ST-Ericsson SA 2011-2013
0004  *
0005  * Author: Mathieu Poirier <mathieu.poirier@linaro.org> for ST-Ericsson
0006  * Author: Jonas Aaberg <jonas.aberg@stericsson.com> for ST-Ericsson
0007  */
0008
0009 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0010
0011 #include <linux/module.h>
0012 #include <linux/kernel.h>
0013 #include <linux/moduleparam.h>
0014 #include <linux/err.h>
0015 #include <linux/uaccess.h>
0016 #include <linux/watchdog.h>
0017 #include <linux/platform_device.h>
0018
0019 #include <linux/mfd/dbx500-prcmu.h>
0020
0021 #define WATCHDOG_TIMEOUT 600 /* 10 minutes */
0022
0023 #define WATCHDOG_MIN    0
0024 #define WATCHDOG_MAX28  268435  /* 28 bit resolution in ms == 268435.455 s */
0025
0026 static unsigned int timeout = WATCHDOG_TIMEOUT;
0027 module_param(timeout, uint, 0);
0028 MODULE_PARM_DESC(timeout,
0029     "Watchdog timeout in seconds. default="
0030                 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
0031
0032 static bool nowayout = WATCHDOG_NOWAYOUT;
0033 module_param(nowayout, bool, 0);
0034 MODULE_PARM_DESC(nowayout,
0035     "Watchdog cannot be stopped once started (default="
0036                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
0037
0038 static int db8500_wdt_start(struct watchdog_device *wdd)
0039 {
0040     return prcmu_enable_a9wdog(PRCMU_WDOG_ALL);
0041 }
0042
0043 static int db8500_wdt_stop(struct watchdog_device *wdd)
0044 {
0045     return prcmu_disable_a9wdog(PRCMU_WDOG_ALL);
0046 }
0047
0048 static int db8500_wdt_keepalive(struct watchdog_device *wdd)
0049 {
0050     return prcmu_kick_a9wdog(PRCMU_WDOG_ALL);
0051 }
0052
0053 static int db8500_wdt_set_timeout(struct watchdog_device *wdd,
0054                  unsigned int timeout)
0055 {
0056     db8500_wdt_stop(wdd);
0057     prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
0058     db8500_wdt_start(wdd);
0059
0060     return 0;
0061 }
0062
0063 static const struct watchdog_info db8500_wdt_info = {
0064     .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
0065     .identity = "DB8500 WDT",
0066     .firmware_version = 1,
0067 };
0068
0069 static const struct watchdog_ops db8500_wdt_ops = {
0070     .owner = THIS_MODULE,
0071     .start = db8500_wdt_start,
0072     .stop  = db8500_wdt_stop,
0073     .ping  = db8500_wdt_keepalive,
0074     .set_timeout = db8500_wdt_set_timeout,
0075 };
0076
0077 static struct watchdog_device db8500_wdt = {
0078     .info = &db8500_wdt_info,
0079     .ops = &db8500_wdt_ops,
0080     .min_timeout = WATCHDOG_MIN,
0081     .max_timeout = WATCHDOG_MAX28,
0082 };
0083
0084 static int db8500_wdt_probe(struct platform_device *pdev)
0085 {
0086     struct device *dev = &pdev->dev;
0087     int ret;
0088
0089     timeout = 600; /* Default to 10 minutes */
0090     db8500_wdt.parent = dev;
0091     watchdog_set_nowayout(&db8500_wdt, nowayout);
0092
0093     /* disable auto off on sleep */
0094     prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
0095
0096     /* set HW initial value */
0097     prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
0098
0099     ret = devm_watchdog_register_device(dev, &db8500_wdt);
0100     if (ret)
0101         return ret;
0102
0103     dev_info(dev, "initialized\n");
0104
0105     return 0;
0106 }
0107
0108 #ifdef CONFIG_PM
0109 static int db8500_wdt_suspend(struct platform_device *pdev,
0110                  pm_message_t state)
0111 {
0112     if (watchdog_active(&db8500_wdt)) {
0113         db8500_wdt_stop(&db8500_wdt);
0114         prcmu_config_a9wdog(PRCMU_WDOG_CPU1, true);
0115
0116         prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
0117         db8500_wdt_start(&db8500_wdt);
0118     }
0119     return 0;
0120 }
0121
0122 static int db8500_wdt_resume(struct platform_device *pdev)
0123 {
0124     if (watchdog_active(&db8500_wdt)) {
0125         db8500_wdt_stop(&db8500_wdt);
0126         prcmu_config_a9wdog(PRCMU_WDOG_CPU1, false);
0127
0128         prcmu_load_a9wdog(PRCMU_WDOG_ALL, timeout * 1000);
0129         db8500_wdt_start(&db8500_wdt);
0130     }
0131     return 0;
0132 }
0133 #else
0134 #define db8500_wdt_suspend NULL
0135 #define db8500_wdt_resume NULL
0136 #endif
0137
0138 static struct platform_driver db8500_wdt_driver = {
0139     .probe      = db8500_wdt_probe,
0140     .suspend    = db8500_wdt_suspend,
0141     .resume     = db8500_wdt_resume,
0142     .driver     = {
0143         .name   = "db8500_wdt",
0144     },
0145 };
0146
0147 module_platform_driver(db8500_wdt_driver);
0148
0149 MODULE_AUTHOR("Jonas Aaberg <jonas.aberg@stericsson.com>");
0150 MODULE_DESCRIPTION("DB8500 Watchdog Driver");
0151 MODULE_LICENSE("GPL");
0152 MODULE_ALIAS("platform:db8500_wdt");