/* * omap_wdt.c * * Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog * * Author: MontaVista Software, Inc. * <gdavis@mvista.com> or <source@mvista.com> * * 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 <gdavis@mvista.com> * Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk> * * 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 <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/watchdog.h> #include <linux/reboot.h> #include <linux/init.h> #include <linux/err.h> #include <linux/platform_device.h> #include <linux/moduleparam.h> #include <linux/io.h> #include <linux/slab.h> #include <linux/pm_runtime.h> #include <linux/platform_data/omap-wd-timer.h> #include "omap_wdt.h" static unsigned timer_margin; module_param(timer_margin, uint, 0); MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)"); struct omap_wdt_dev { void __iomem *base; /* physical */ struct device *dev; bool omap_wdt_users; struct resource *mem; 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 ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x08) cpu_relax(); wdev->wdt_trgr_pattern = ~wdev->wdt_trgr_pattern; __raw_writel(wdev->wdt_trgr_pattern, (base + OMAP_WATCHDOG_TGR)); /* wait for posted write to complete */ while ((__raw_readl(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 */ __raw_writel(0xBBBB, base + OMAP_WATCHDOG_SPR); while ((__raw_readl(base + OMAP_WATCHDOG_WPS)) & 0x10) cpu_relax(); __raw_writel(0x4444, base + OMAP_WATCHDOG_SPR); while ((__raw_readl(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 */ __raw_writel(0xAAAA, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */ while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x10) cpu_relax(); __raw_writel(0x5555, base + OMAP_WATCHDOG_SPR); /* TIMER_MODE */ while (__raw_readl(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 (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04) cpu_relax(); __raw_writel(pre_margin, base + OMAP_WATCHDOG_LDR); while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x04) cpu_relax(); } static int omap_wdt_start(struct watchdog_device *wdog) { struct omap_wdt_dev *wdev = watchdog_get_drvdata(wdog); void __iomem *base = wdev->base; mutex_lock(&wdev->lock); wdev->omap_wdt_users = true; pm_runtime_get_sync(wdev->dev); /* initialize prescaler */ while (__raw_readl(base + OMAP_WATCHDOG_WPS) & 0x01) cpu_relax(); __raw_writel((1 << 5) | (PTV << 2), base + OMAP_WATCHDOG_CNTRL); while (__raw_readl(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 = watchdog_get_drvdata(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 = watchdog_get_drvdata(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 = watchdog_get_drvdata(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_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 = pdev->dev.platform_data; bool nowayout = WATCHDOG_NOWAYOUT; struct watchdog_device *omap_wdt; struct resource *res, *mem; struct omap_wdt_dev *wdev; u32 rs; int ret; omap_wdt = devm_kzalloc(&pdev->dev, sizeof(*omap_wdt), GFP_KERNEL); if (!omap_wdt) return -ENOMEM; /* reserve static register mappings */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) return -ENOENT; mem = devm_request_mem_region(&pdev->dev, res->start, resource_size(res), pdev->name); if (!mem) return -EBUSY; wdev = devm_kzalloc(&pdev->dev, sizeof(*wdev), GFP_KERNEL); if (!wdev) return -ENOMEM; wdev->omap_wdt_users = false; wdev->mem = mem; wdev->dev = &pdev->dev; wdev->wdt_trgr_pattern = 0x1234; mutex_init(&wdev->lock); wdev->base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); if (!wdev->base) return -ENOMEM; omap_wdt->info = &omap_wdt_info; omap_wdt->ops = &omap_wdt_ops; omap_wdt->min_timeout = TIMER_MARGIN_MIN; omap_wdt->max_timeout = TIMER_MARGIN_MAX; if (timer_margin >= TIMER_MARGIN_MIN && timer_margin <= TIMER_MARGIN_MAX) omap_wdt->timeout = timer_margin; else omap_wdt->timeout = TIMER_MARGIN_DEFAULT; watchdog_set_drvdata(omap_wdt, wdev); watchdog_set_nowayout(omap_wdt, nowayout); platform_set_drvdata(pdev, omap_wdt); pm_runtime_enable(wdev->dev); pm_runtime_get_sync(wdev->dev); if (pdata && pdata->read_reset_sources) rs = pdata->read_reset_sources(); else rs = 0; omap_wdt->bootstatus = (rs & (1 << OMAP_MPU_WD_RST_SRC_ID_SHIFT)) ? WDIOF_CARDRESET : 0; omap_wdt_disable(wdev); ret = watchdog_register_device(omap_wdt); if (ret) { pm_runtime_disable(wdev->dev); return ret; } pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n", __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF, omap_wdt->timeout); pm_runtime_put_sync(wdev->dev); return 0; } static void omap_wdt_shutdown(struct platform_device *pdev) { struct watchdog_device *wdog = platform_get_drvdata(pdev); struct omap_wdt_dev *wdev = watchdog_get_drvdata(wdog); 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 watchdog_device *wdog = platform_get_drvdata(pdev); struct omap_wdt_dev *wdev = watchdog_get_drvdata(wdog); pm_runtime_disable(wdev->dev); watchdog_unregister_device(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 watchdog_device *wdog = platform_get_drvdata(pdev); struct omap_wdt_dev *wdev = watchdog_get_drvdata(wdog); 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 watchdog_device *wdog = platform_get_drvdata(pdev); struct omap_wdt_dev *wdev = watchdog_get_drvdata(wdog); 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 = { .owner = THIS_MODULE, .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");