/* * Watchdog driver for Broadcom BCM2835 * * "bcm2708_wdog" driver written by Luke Diamand that was obtained from * branch "rpi-3.6.y" of git://github.com/raspberrypi/linux.git was used * as a hardware reference for the Broadcom BCM2835 watchdog timer. * * Copyright (C) 2013 Lubomir Rintel <lkundrak@v3.sk> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by the * Free Software Foundation; either version 2 of the License, or (at your * option) any later version. */ #include <linux/types.h> #include <linux/module.h> #include <linux/io.h> #include <linux/watchdog.h> #include <linux/platform_device.h> #include <linux/of_address.h> #define PM_RSTC 0x1c #define PM_WDOG 0x24 #define PM_PASSWORD 0x5a000000 #define PM_WDOG_TIME_SET 0x000fffff #define PM_RSTC_WRCFG_CLR 0xffffffcf #define PM_RSTC_WRCFG_SET 0x00000030 #define PM_RSTC_WRCFG_FULL_RESET 0x00000020 #define PM_RSTC_RESET 0x00000102 #define SECS_TO_WDOG_TICKS(x) ((x) << 16) #define WDOG_TICKS_TO_SECS(x) ((x) >> 16) struct bcm2835_wdt { void __iomem *base; spinlock_t lock; }; static unsigned int heartbeat; static bool nowayout = WATCHDOG_NOWAYOUT; static int bcm2835_wdt_start(struct watchdog_device *wdog) { struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); uint32_t cur; unsigned long flags; spin_lock_irqsave(&wdt->lock, flags); writel_relaxed(PM_PASSWORD | (SECS_TO_WDOG_TICKS(wdog->timeout) & PM_WDOG_TIME_SET), wdt->base + PM_WDOG); cur = readl_relaxed(wdt->base + PM_RSTC); writel_relaxed(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) | PM_RSTC_WRCFG_FULL_RESET, wdt->base + PM_RSTC); spin_unlock_irqrestore(&wdt->lock, flags); return 0; } static int bcm2835_wdt_stop(struct watchdog_device *wdog) { struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); writel_relaxed(PM_PASSWORD | PM_RSTC_RESET, wdt->base + PM_RSTC); dev_info(wdog->dev, "Watchdog timer stopped"); return 0; } static int bcm2835_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) { wdog->timeout = t; return 0; } static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog) { struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); uint32_t ret = readl_relaxed(wdt->base + PM_WDOG); return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET); } static struct watchdog_ops bcm2835_wdt_ops = { .owner = THIS_MODULE, .start = bcm2835_wdt_start, .stop = bcm2835_wdt_stop, .set_timeout = bcm2835_wdt_set_timeout, .get_timeleft = bcm2835_wdt_get_timeleft, }; static struct watchdog_info bcm2835_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "Broadcom BCM2835 Watchdog timer", }; static struct watchdog_device bcm2835_wdt_wdd = { .info = &bcm2835_wdt_info, .ops = &bcm2835_wdt_ops, .min_timeout = 1, .max_timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), }; static int bcm2835_wdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct device_node *np = dev->of_node; struct bcm2835_wdt *wdt; int err; wdt = devm_kzalloc(dev, sizeof(struct bcm2835_wdt), GFP_KERNEL); if (!wdt) return -ENOMEM; platform_set_drvdata(pdev, wdt); spin_lock_init(&wdt->lock); wdt->base = of_iomap(np, 0); if (!wdt->base) { dev_err(dev, "Failed to remap watchdog regs"); return -ENODEV; } watchdog_set_drvdata(&bcm2835_wdt_wdd, wdt); watchdog_init_timeout(&bcm2835_wdt_wdd, heartbeat, dev); watchdog_set_nowayout(&bcm2835_wdt_wdd, nowayout); err = watchdog_register_device(&bcm2835_wdt_wdd); if (err) { dev_err(dev, "Failed to register watchdog device"); iounmap(wdt->base); return err; } dev_info(dev, "Broadcom BCM2835 watchdog timer"); return 0; } static int bcm2835_wdt_remove(struct platform_device *pdev) { struct bcm2835_wdt *wdt = platform_get_drvdata(pdev); watchdog_unregister_device(&bcm2835_wdt_wdd); iounmap(wdt->base); return 0; } static void bcm2835_wdt_shutdown(struct platform_device *pdev) { bcm2835_wdt_stop(&bcm2835_wdt_wdd); } static const struct of_device_id bcm2835_wdt_of_match[] = { { .compatible = "brcm,bcm2835-pm-wdt", }, {}, }; MODULE_DEVICE_TABLE(of, bcm2835_wdt_of_match); static struct platform_driver bcm2835_wdt_driver = { .probe = bcm2835_wdt_probe, .remove = bcm2835_wdt_remove, .shutdown = bcm2835_wdt_shutdown, .driver = { .name = "bcm2835-wdt", .owner = THIS_MODULE, .of_match_table = bcm2835_wdt_of_match, }, }; module_platform_driver(bcm2835_wdt_driver); module_param(heartbeat, uint, 0); MODULE_PARM_DESC(heartbeat, "Initial watchdog heartbeat in seconds"); module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>"); MODULE_DESCRIPTION("Driver for Broadcom BCM2835 watchdog timer"); MODULE_LICENSE("GPL");