/* * Watchdog driver for Cirrus Logic EP93xx family of devices. * * Copyright (c) 2004 Ray Lehtiniemi * Copyright (c) 2006 Tower Technologies * Based on ep93xx driver, bits from alim7101_wdt.c * * Authors: Ray Lehtiniemi <rayl@mail.com>, * Alessandro Zummo <a.zummo@towertech.it> * * Copyright (c) 2012 H Hartley Sweeten <hsweeten@visionengravers.com> * Convert to a platform device and use the watchdog framework API * * This file is licensed under the terms of the GNU General Public * License version 2. This program is licensed "as is" without any * warranty of any kind, whether express or implied. * * This watchdog fires after 250msec, which is a too short interval * for us to rely on the user space daemon alone. So we ping the * wdt each ~200msec and eventually stop doing it if the user space * daemon dies. * * TODO: * * - Test last reset from watchdog status * - Add a few missing ioctls */ #include <linux/platform_device.h> #include <linux/module.h> #include <linux/watchdog.h> #include <linux/timer.h> #include <linux/io.h> #define WDT_VERSION "0.4" /* default timeout (secs) */ #define WDT_TIMEOUT 30 static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); static unsigned int timeout = WDT_TIMEOUT; module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WDT_TIMEOUT) ")"); static void __iomem *mmio_base; static struct timer_list timer; static unsigned long next_heartbeat; #define EP93XX_WATCHDOG 0x00 #define EP93XX_WDSTATUS 0x04 /* reset the wdt every ~200ms - the heartbeat of the device is 0.250 seconds*/ #define WDT_INTERVAL (HZ/5) static void ep93xx_wdt_timer_ping(unsigned long data) { if (time_before(jiffies, next_heartbeat)) writel(0x5555, mmio_base + EP93XX_WATCHDOG); /* Re-set the timer interval */ mod_timer(&timer, jiffies + WDT_INTERVAL); } static int ep93xx_wdt_start(struct watchdog_device *wdd) { next_heartbeat = jiffies + (timeout * HZ); writel(0xaaaa, mmio_base + EP93XX_WATCHDOG); mod_timer(&timer, jiffies + WDT_INTERVAL); return 0; } static int ep93xx_wdt_stop(struct watchdog_device *wdd) { del_timer_sync(&timer); writel(0xaa55, mmio_base + EP93XX_WATCHDOG); return 0; } static int ep93xx_wdt_keepalive(struct watchdog_device *wdd) { /* user land ping */ next_heartbeat = jiffies + (timeout * HZ); return 0; } static const struct watchdog_info ep93xx_wdt_ident = { .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "EP93xx Watchdog", }; static struct watchdog_ops ep93xx_wdt_ops = { .owner = THIS_MODULE, .start = ep93xx_wdt_start, .stop = ep93xx_wdt_stop, .ping = ep93xx_wdt_keepalive, }; static struct watchdog_device ep93xx_wdt_wdd = { .info = &ep93xx_wdt_ident, .ops = &ep93xx_wdt_ops, }; static int ep93xx_wdt_probe(struct platform_device *pdev) { struct resource *res; unsigned long val; int err; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); mmio_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(mmio_base)) return PTR_ERR(mmio_base); if (timeout < 1 || timeout > 3600) { timeout = WDT_TIMEOUT; dev_warn(&pdev->dev, "timeout value must be 1<=x<=3600, using %d\n", timeout); } val = readl(mmio_base + EP93XX_WATCHDOG); ep93xx_wdt_wdd.bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0; ep93xx_wdt_wdd.timeout = timeout; watchdog_set_nowayout(&ep93xx_wdt_wdd, nowayout); setup_timer(&timer, ep93xx_wdt_timer_ping, 1); err = watchdog_register_device(&ep93xx_wdt_wdd); if (err) return err; dev_info(&pdev->dev, "EP93XX watchdog, driver version " WDT_VERSION "%s\n", (val & 0x08) ? " (nCS1 disable detected)" : ""); return 0; } static int ep93xx_wdt_remove(struct platform_device *pdev) { watchdog_unregister_device(&ep93xx_wdt_wdd); return 0; } static struct platform_driver ep93xx_wdt_driver = { .driver = { .owner = THIS_MODULE, .name = "ep93xx-wdt", }, .probe = ep93xx_wdt_probe, .remove = ep93xx_wdt_remove, }; module_platform_driver(ep93xx_wdt_driver); MODULE_AUTHOR("Ray Lehtiniemi <rayl@mail.com>"); MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>"); MODULE_AUTHOR("H Hartley Sweeten <hsweeten@visionengravers.com>"); MODULE_DESCRIPTION("EP93xx Watchdog"); MODULE_LICENSE("GPL"); MODULE_VERSION(WDT_VERSION);