/* * Copyright (c) 2009 Nuvoton technology corporation. * * Wan ZongShun <mcuos.com@gmail.com> * * 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;version 2 of the License. * */ #include <linux/bitops.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/io.h> #include <linux/clk.h> #include <linux/kernel.h> #include <linux/miscdevice.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/platform_device.h> #include <linux/interrupt.h> #include <linux/types.h> #include <linux/watchdog.h> #include <linux/uaccess.h> #define REG_WTCR 0x1c #define WTCLK (0x01 << 10) #define WTE (0x01 << 7) /*wdt enable*/ #define WTIS (0x03 << 4) #define WTIF (0x01 << 3) #define WTRF (0x01 << 2) #define WTRE (0x01 << 1) #define WTR (0x01 << 0) /* * The watchdog time interval can be calculated via following formula: * WTIS real time interval (formula) * 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds * 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds * 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds * 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds * * The external crystal freq is 15Mhz in the nuc900 evaluation board. * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds, * 0x03 = +- 16.92 seconds.. */ #define WDT_HW_TIMEOUT 0x02 #define WDT_TIMEOUT (HZ/2) #define WDT_HEARTBEAT 15 static int heartbeat = WDT_HEARTBEAT; module_param(heartbeat, int, 0); MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. " "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")"); static int nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); struct nuc900_wdt { struct resource *res; struct clk *wdt_clock; struct platform_device *pdev; void __iomem *wdt_base; char expect_close; struct timer_list timer; spinlock_t wdt_lock; unsigned long next_heartbeat; }; static unsigned long nuc900wdt_busy; struct nuc900_wdt *nuc900_wdt; static inline void nuc900_wdt_keepalive(void) { unsigned int val; spin_lock(&nuc900_wdt->wdt_lock); val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); val |= (WTR | WTIF); __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); spin_unlock(&nuc900_wdt->wdt_lock); } static inline void nuc900_wdt_start(void) { unsigned int val; spin_lock(&nuc900_wdt->wdt_lock); val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); val |= (WTRE | WTE | WTR | WTCLK | WTIF); val &= ~WTIS; val |= (WDT_HW_TIMEOUT << 0x04); __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); spin_unlock(&nuc900_wdt->wdt_lock); nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); } static inline void nuc900_wdt_stop(void) { unsigned int val; del_timer(&nuc900_wdt->timer); spin_lock(&nuc900_wdt->wdt_lock); val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); val &= ~WTE; __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); spin_unlock(&nuc900_wdt->wdt_lock); } static inline void nuc900_wdt_ping(void) { nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; } static int nuc900_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(0, &nuc900wdt_busy)) return -EBUSY; nuc900_wdt_start(); return nonseekable_open(inode, file); } static int nuc900_wdt_close(struct inode *inode, struct file *file) { if (nuc900_wdt->expect_close == 42) nuc900_wdt_stop(); else { dev_crit(&nuc900_wdt->pdev->dev, "Unexpected close, not stopping watchdog!\n"); nuc900_wdt_ping(); } nuc900_wdt->expect_close = 0; clear_bit(0, &nuc900wdt_busy); return 0; } static const struct watchdog_info nuc900_wdt_info = { .identity = "nuc900 watchdog", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; static long nuc900_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; int new_value; switch (cmd) { case WDIOC_GETSUPPORT: return copy_to_user(argp, &nuc900_wdt_info, sizeof(nuc900_wdt_info)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_KEEPALIVE: nuc900_wdt_ping(); return 0; case WDIOC_SETTIMEOUT: if (get_user(new_value, p)) return -EFAULT; heartbeat = new_value; nuc900_wdt_ping(); return put_user(new_value, p); case WDIOC_GETTIMEOUT: return put_user(heartbeat, p); default: return -ENOTTY; } } static ssize_t nuc900_wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { if (!len) return 0; /* Scan for magic character */ if (!nowayout) { size_t i; nuc900_wdt->expect_close = 0; for (i = 0; i < len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') { nuc900_wdt->expect_close = 42; break; } } } nuc900_wdt_ping(); return len; } static void nuc900_wdt_timer_ping(unsigned long data) { if (time_before(jiffies, nuc900_wdt->next_heartbeat)) { nuc900_wdt_keepalive(); mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); } else dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n"); } static const struct file_operations nuc900wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .unlocked_ioctl = nuc900_wdt_ioctl, .open = nuc900_wdt_open, .release = nuc900_wdt_close, .write = nuc900_wdt_write, }; static struct miscdevice nuc900wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &nuc900wdt_fops, }; static int __devinit nuc900wdt_probe(struct platform_device *pdev) { int ret = 0; nuc900_wdt = kzalloc(sizeof(struct nuc900_wdt), GFP_KERNEL); if (!nuc900_wdt) return -ENOMEM; nuc900_wdt->pdev = pdev; spin_lock_init(&nuc900_wdt->wdt_lock); nuc900_wdt->res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (nuc900_wdt->res == NULL) { dev_err(&pdev->dev, "no memory resource specified\n"); ret = -ENOENT; goto err_get; } if (!request_mem_region(nuc900_wdt->res->start, resource_size(nuc900_wdt->res), pdev->name)) { dev_err(&pdev->dev, "failed to get memory region\n"); ret = -ENOENT; goto err_get; } nuc900_wdt->wdt_base = ioremap(nuc900_wdt->res->start, resource_size(nuc900_wdt->res)); if (nuc900_wdt->wdt_base == NULL) { dev_err(&pdev->dev, "failed to ioremap() region\n"); ret = -EINVAL; goto err_req; } nuc900_wdt->wdt_clock = clk_get(&pdev->dev, NULL); if (IS_ERR(nuc900_wdt->wdt_clock)) { dev_err(&pdev->dev, "failed to find watchdog clock source\n"); ret = PTR_ERR(nuc900_wdt->wdt_clock); goto err_map; } clk_enable(nuc900_wdt->wdt_clock); setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0); if (misc_register(&nuc900wdt_miscdev)) { dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n", WATCHDOG_MINOR, ret); goto err_clk; } return 0; err_clk: clk_disable(nuc900_wdt->wdt_clock); clk_put(nuc900_wdt->wdt_clock); err_map: iounmap(nuc900_wdt->wdt_base); err_req: release_mem_region(nuc900_wdt->res->start, resource_size(nuc900_wdt->res)); err_get: kfree(nuc900_wdt); return ret; } static int __devexit nuc900wdt_remove(struct platform_device *pdev) { misc_deregister(&nuc900wdt_miscdev); clk_disable(nuc900_wdt->wdt_clock); clk_put(nuc900_wdt->wdt_clock); iounmap(nuc900_wdt->wdt_base); release_mem_region(nuc900_wdt->res->start, resource_size(nuc900_wdt->res)); kfree(nuc900_wdt); return 0; } static struct platform_driver nuc900wdt_driver = { .probe = nuc900wdt_probe, .remove = __devexit_p(nuc900wdt_remove), .driver = { .name = "nuc900-wdt", .owner = THIS_MODULE, }, }; static int __init nuc900_wdt_init(void) { return platform_driver_register(&nuc900wdt_driver); } static void __exit nuc900_wdt_exit(void) { platform_driver_unregister(&nuc900wdt_driver); } module_init(nuc900_wdt_init); module_exit(nuc900_wdt_exit); MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>"); MODULE_DESCRIPTION("Watchdog driver for NUC900"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); MODULE_ALIAS("platform:nuc900-wdt");