/* * 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. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "omap_wdt.h" static struct platform_device *omap_wdt_dev; static unsigned timer_margin; module_param(timer_margin, uint, 0); MODULE_PARM_DESC(timer_margin, "initial watchdog timeout (in seconds)"); static unsigned int wdt_trgr_pattern = 0x1234; static spinlock_t wdt_lock; struct omap_wdt_dev { void __iomem *base; /* physical */ struct device *dev; int omap_wdt_users; struct resource *mem; struct miscdevice omap_wdt_miscdev; }; static void omap_wdt_ping(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(); wdt_trgr_pattern = ~wdt_trgr_pattern; __raw_writel(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_adjust_timeout(unsigned new_timeout) { if (new_timeout < TIMER_MARGIN_MIN) new_timeout = TIMER_MARGIN_DEFAULT; if (new_timeout > TIMER_MARGIN_MAX) new_timeout = TIMER_MARGIN_MAX; timer_margin = new_timeout; } static void omap_wdt_set_timeout(struct omap_wdt_dev *wdev) { u32 pre_margin = GET_WLDR_VAL(timer_margin); 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(); } /* * Allow only one task to hold it open */ static int omap_wdt_open(struct inode *inode, struct file *file) { struct omap_wdt_dev *wdev = platform_get_drvdata(omap_wdt_dev); void __iomem *base = wdev->base; if (test_and_set_bit(1, (unsigned long *)&(wdev->omap_wdt_users))) return -EBUSY; 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(); file->private_data = (void *) wdev; omap_wdt_set_timeout(wdev); omap_wdt_ping(wdev); /* trigger loading of new timeout value */ omap_wdt_enable(wdev); return nonseekable_open(inode, file); } static int omap_wdt_release(struct inode *inode, struct file *file) { struct omap_wdt_dev *wdev = file->private_data; /* * Shut off the timer unless NOWAYOUT is defined. */ #ifndef CONFIG_WATCHDOG_NOWAYOUT omap_wdt_disable(wdev); pm_runtime_put_sync(wdev->dev); #else printk(KERN_CRIT "omap_wdt: Unexpected close, not stopping!\n"); #endif wdev->omap_wdt_users = 0; return 0; } static ssize_t omap_wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { struct omap_wdt_dev *wdev = file->private_data; /* Refresh LOAD_TIME. */ if (len) { spin_lock(&wdt_lock); omap_wdt_ping(wdev); spin_unlock(&wdt_lock); } return len; } static long omap_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct omap_wdt_dev *wdev; int new_margin; static const struct watchdog_info ident = { .identity = "OMAP Watchdog", .options = WDIOF_SETTIMEOUT, .firmware_version = 0, }; wdev = file->private_data; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user((struct watchdog_info __user *)arg, &ident, sizeof(ident)); case WDIOC_GETSTATUS: return put_user(0, (int __user *)arg); case WDIOC_GETBOOTSTATUS: if (cpu_is_omap16xx()) return put_user(__raw_readw(ARM_SYSST), (int __user *)arg); if (cpu_is_omap24xx()) return put_user(omap_prcm_get_reset_sources(), (int __user *)arg); case WDIOC_KEEPALIVE: spin_lock(&wdt_lock); omap_wdt_ping(wdev); spin_unlock(&wdt_lock); return 0; case WDIOC_SETTIMEOUT: if (get_user(new_margin, (int __user *)arg)) return -EFAULT; omap_wdt_adjust_timeout(new_margin); spin_lock(&wdt_lock); omap_wdt_disable(wdev); omap_wdt_set_timeout(wdev); omap_wdt_enable(wdev); omap_wdt_ping(wdev); spin_unlock(&wdt_lock); /* Fall */ case WDIOC_GETTIMEOUT: return put_user(timer_margin, (int __user *)arg); default: return -ENOTTY; } } static const struct file_operations omap_wdt_fops = { .owner = THIS_MODULE, .write = omap_wdt_write, .unlocked_ioctl = omap_wdt_ioctl, .open = omap_wdt_open, .release = omap_wdt_release, .llseek = no_llseek, }; static int __devinit omap_wdt_probe(struct platform_device *pdev) { struct resource *res, *mem; struct omap_wdt_dev *wdev; int ret; /* reserve static register mappings */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { ret = -ENOENT; goto err_get_resource; } if (omap_wdt_dev) { ret = -EBUSY; goto err_busy; } mem = request_mem_region(res->start, resource_size(res), pdev->name); if (!mem) { ret = -EBUSY; goto err_busy; } wdev = kzalloc(sizeof(struct omap_wdt_dev), GFP_KERNEL); if (!wdev) { ret = -ENOMEM; goto err_kzalloc; } wdev->omap_wdt_users = 0; wdev->mem = mem; wdev->dev = &pdev->dev; wdev->base = ioremap(res->start, resource_size(res)); if (!wdev->base) { ret = -ENOMEM; goto err_ioremap; } platform_set_drvdata(pdev, wdev); pm_runtime_enable(wdev->dev); pm_runtime_get_sync(wdev->dev); omap_wdt_disable(wdev); omap_wdt_adjust_timeout(timer_margin); wdev->omap_wdt_miscdev.parent = &pdev->dev; wdev->omap_wdt_miscdev.minor = WATCHDOG_MINOR; wdev->omap_wdt_miscdev.name = "watchdog"; wdev->omap_wdt_miscdev.fops = &omap_wdt_fops; ret = misc_register(&(wdev->omap_wdt_miscdev)); if (ret) goto err_misc; pr_info("OMAP Watchdog Timer Rev 0x%02x: initial timeout %d sec\n", __raw_readl(wdev->base + OMAP_WATCHDOG_REV) & 0xFF, timer_margin); pm_runtime_put_sync(wdev->dev); omap_wdt_dev = pdev; return 0; err_misc: platform_set_drvdata(pdev, NULL); iounmap(wdev->base); err_ioremap: wdev->base = NULL; kfree(wdev); err_kzalloc: release_mem_region(res->start, resource_size(res)); err_busy: err_get_resource: return ret; } static void omap_wdt_shutdown(struct platform_device *pdev) { struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); if (wdev->omap_wdt_users) { omap_wdt_disable(wdev); pm_runtime_put_sync(wdev->dev); } } static int __devexit omap_wdt_remove(struct platform_device *pdev) { struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) return -ENOENT; misc_deregister(&(wdev->omap_wdt_miscdev)); release_mem_region(res->start, resource_size(res)); platform_set_drvdata(pdev, NULL); iounmap(wdev->base); kfree(wdev); omap_wdt_dev = NULL; 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); if (wdev->omap_wdt_users) { omap_wdt_disable(wdev); pm_runtime_put_sync(wdev->dev); } return 0; } static int omap_wdt_resume(struct platform_device *pdev) { struct omap_wdt_dev *wdev = platform_get_drvdata(pdev); if (wdev->omap_wdt_users) { pm_runtime_get_sync(wdev->dev); omap_wdt_enable(wdev); omap_wdt_ping(wdev); } return 0; } #else #define omap_wdt_suspend NULL #define omap_wdt_resume NULL #endif static struct platform_driver omap_wdt_driver = { .probe = omap_wdt_probe, .remove = __devexit_p(omap_wdt_remove), .shutdown = omap_wdt_shutdown, .suspend = omap_wdt_suspend, .resume = omap_wdt_resume, .driver = { .owner = THIS_MODULE, .name = "omap_wdt", }, }; static int __init omap_wdt_init(void) { spin_lock_init(&wdt_lock); return platform_driver_register(&omap_wdt_driver); } static void __exit omap_wdt_exit(void) { platform_driver_unregister(&omap_wdt_driver); } module_init(omap_wdt_init); module_exit(omap_wdt_exit); MODULE_AUTHOR("George G. Davis"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); MODULE_ALIAS("platform:omap_wdt");