/* * omap_wdt.c * * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog * * Author: MontaVista Software, Inc. * or * * 2003 (c) MontaVista Software, Inc. 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. * * History: * * 20030527: George G. Davis * Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c * (c) Copyright 2000 Oleg Drokin * Based on SoftDog driver by Alan Cox * * Copyright (c) 2004 Texas Instruments. * 1. Modified to support OMAP1610 32-KHz watchdog timer * 2. Ported to 2.6 kernel * * Copyright (c) 2005 David Brownell * Use the driver model and standard identifiers; handle bigger timeouts. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include "omap_wdt.h" static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static unsigned timer_margin; module_param(timer_margin, uint, 0); MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)"); #define to_omap_wdt_dev(_wdog) container_of(_wdog, struct omap_wdt_dev, wdog) struct omap_wdt_dev { struct watchdog_device wdog; void __iomem *base; /* physical */ struct device *dev; bool omap_wdt_users; int wdt_trgr_pattern; struct mutex lock; /* to avoid races with PM */ }; static void omap_wdt_reload(struct omap_wdt_dev *wdev) { void __iomem *base = wdev->base; /* wait for posted write to complete */ while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08) cpu_relax(); wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern; writel_relaxed(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR)); /* wait for posted write to complete */ while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x08) cpu_relax(); /* reloaded WCRR from WLDR */ } static void omap_wdt_enable(struct omap_wdt_dev *wdev) { void __iomem *base = wdev->base; /* Sequence to enable the watchdog */ writel_relaxed(0xBBBB, base + OMAP_WATCHDOG_SPR); while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10) cpu_relax(); writel_relaxed(0x4444, base + OMAP_WATCHDOG_SPR); while ((readl_relaxed(base + OMAP_WATCHDOG_WPS)) & 0x10) cpu_relax(); } static void omap_wdt_disable(struct omap_wdt_dev *wdev) { void __iomem *base = wdev->base; /* sequence required to disable watchdog */ writel_relaxed(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */ while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10) cpu_relax(); writel_relaxed(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */ while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x10) cpu_relax(); } static void omap_wdt_set_timer(struct omap_wdt_dev *wdev, unsigned int timeout) { u32 pre_margin = GET_WLDR_VAL(timeout); void __iomem *base = wdev->base; /* just count up at 32 KHz */ while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04) cpu_relax(); writel_relaxed(pre_margin, base + OMAP_WATCHDOG_LDR); while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x04) cpu_relax(); } static int omap_wdt_start(struct watchdog_device *wdog) { struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); void __iomem *base = wdev->base; mutex_lock(&wdev->lock); wdev->omap_wdt_users = true; pm_runtime_get_sync(wdev->dev); /* * Make sure the watchdog is disabled. This is unfortunately required * because writing to various registers with the watchdog running has no * effect. */ omap_wdt_disable(wdev); /* initialize prescaler */ while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01) cpu_relax(); writel_relaxed((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL); while (readl_relaxed(base + OMAP_WATCHDOG_WPS) & 0x01) cpu_relax(); omap_wdt_set_timer(wdev, wdog->timeout); omap_wdt_reload(wdev); /* trigger loading of new timeout value */ omap_wdt_enable(wdev); mutex_unlock(&wdev->lock); return 0; } static int omap_wdt_stop(struct watchdog_device *wdog) { struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); mutex_lock(&wdev->lock); omap_wdt_disable(wdev); pm_runtime_put_sync(wdev->dev); wdev->omap_wdt_users = false; mutex_unlock(&wdev->lock); return 0; } static int omap_wdt_ping(struct watchdog_device *wdog) { struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); mutex_lock(&wdev->lock); omap_wdt_reload(wdev); mutex_unlock(&wdev->lock); return 0; } static int omap_wdt_set_timeout(struct watchdog_device *wdog, unsigned int timeout) { struct omap_wdt_dev *wdev = to_omap_wdt_dev(wdog); mutex_lock(&wdev->lock); omap_wdt_disable(wdev); omap_wdt_set_timer(wdev, timeout); omap_wdt_enable(wdev); omap_wdt_reload(wdev); wdog->timeout = timeout; mutex_unlock(&wdev->lock); return 0; } static const struct watchdog_info omap_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "OMAP Watchdog", }; static const struct watchdog_ops omap_wdt_ops = { .owner = THIS_MODULE, .start = omap_wdt_start, .stop = omap_wdt_stop, .ping = omap_wdt_ping, .set_timeout = omap_wdt_set_timeout, }; static int omap_wdt_probe(struct platform_device *pdev) { struct omap_wd_timer_platform_data *pdata = dev_get_platdata(&pdev->dev); struct resource *res; struct omap_wdt_dev *wdev; int ret; wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); if (!wdev) return -ENOMEM; wdev->omap_wdt_users = false; wdev->dev = &pdev->dev; wdev->wdt_trgr_pattern = 0x1234; mutex_init(&wdev->lock); /* reserve static register mappings */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); wdev->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(wdev->base)) return PTR_ERR(wdev->base); wdev->wdog.info = &omap_wdt_info; wdev->wdog.ops = &omap_wdt_ops; wdev->wdog.min_timeout = TIMER_MARGIN_MIN; wdev->wdog.max_timeout = TIMER_MARGIN_MAX; if (watchdog_init_timeout(&wdev->wdog, timer_margin, &pdev->dev) < 0) wdev->wdog.timeout = TIMER_MARGIN_DEFAULT; watchdog_set_nowayout(&wdev->wdog, nowayout); platform_set_drvdata(pdev, wdev); pm_runtime_enable(wdev->dev); pm_runtime_get_sync(wdev->dev); if (pdata && pdata->read_reset_sources) { u32 rs = pdata->read_reset_sources(); if (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT)) wdev->wdog.bootstatus = WDIOF_CARDRESET; } omap_wdt_disable(wdev); ret = watchdog_register_device(&wdev->wdog); if (ret) { pm_runtime_disable(wdev->dev); return ret; } pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n", readl_relaxed(wdev->base + OMAP_WATCHDOG_REV) & 0xFF, wdev->wdog.timeout); pm_runtime_put_sync(wdev->dev); return 0; } static void omap_wdt_shutdown(struct platform_device *pdev) { struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); mutex_lock(&wdev->lock); if (wdev->omap_wdt_users) { omap_wdt_disable(wdev); pm_runtime_put_sync(wdev->dev); } mutex_unlock(&wdev->lock); } static int omap_wdt_remove(struct platform_device *pdev) { struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); pm_runtime_disable(wdev->dev); watchdog_unregister_device(&wdev->wdog); return 0; } #ifdef CONFIG_PM /* REVISIT ... not clear this is the best way to handle system suspend; and * it's very inappropriate for selective device suspend (e.g. suspending this * through sysfs rather than by stopping the watchdog daemon). Also, this * may not play well enough with NOWAYOUT... */ static int omap_wdt_suspend(struct platform_device *pdev, pm_message_t state) { struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); mutex_lock(&wdev->lock); if (wdev->omap_wdt_users) { omap_wdt_disable(wdev); pm_runtime_put_sync(wdev->dev); } mutex_unlock(&wdev->lock); return 0; } static int omap_wdt_resume(struct platform_device *pdev) { struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); mutex_lock(&wdev->lock); if (wdev->omap_wdt_users) { pm_runtime_get_sync(wdev->dev); omap_wdt_enable(wdev); omap_wdt_reload(wdev); } mutex_unlock(&wdev->lock); return 0; } #else #define omap_wdt_suspend NULL #define omap_wdt_resume NULL #endif static const struct of_device_id omap_wdt_of_match[] = { { .compatible = "ti,omap3-wdt", }, {}, }; MODULE_DEVICE_TABLE(of, omap_wdt_of_match); static struct platform_driver omap_wdt_driver = { .probe = omap_wdt_probe, .remove = omap_wdt_remove, .shutdown = omap_wdt_shutdown, .suspend = omap_wdt_suspend, .resume = omap_wdt_resume, .driver = { .name = "omap_wdt", .of_match_table = omap_wdt_of_match, }, }; module_platform_driver(omap_wdt_driver); MODULE_AUTHOR("George G. Davis"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:omap_wdt");