/* * Driver for the Atheros AR71xx SoC's built-in hardware watchdog timer. * * Copyright (C) 2008 Gabor Juhos <juhosg@openwrt.org> * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org> * * This driver was based on: drivers/watchdog/ixp4xx_wdt.c * Author: Deepak Saxena <dsaxena@plexity.net> * Copyright 2004 (c) MontaVista, Software, Inc. * * which again was based on sa1100 driver, * Copyright (C) 2000 Oleg Drokin <green@crimea.edu> * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published * by the Free Software Foundation. * */ #include <linux/bitops.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/miscdevice.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/platform_device.h> #include <linux/types.h> #include <linux/watchdog.h> #include <asm/mach-ar71xx/ar71xx.h> #define DRV_NAME "ar71xx-wdt" #define DRV_DESC "Atheros AR71xx hardware watchdog driver" #define DRV_VERSION "0.1.0" #define WDT_TIMEOUT 15 /* seconds */ static int nowayout = WATCHDOG_NOWAYOUT; #ifdef CONFIG_WATCHDOG_NOWAYOUT module_param(nowayout, int, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); #endif static unsigned long wdt_flags; #define WDT_FLAGS_BUSY 0 #define WDT_FLAGS_EXPECT_CLOSE 1 static int wdt_timeout = WDT_TIMEOUT; static int boot_status; static int max_timeout; static void inline ar71xx_wdt_keepalive(void) { ar71xx_reset_wr(AR71XX_RESET_REG_WDOG, ar71xx_ahb_freq * wdt_timeout); } static void inline ar71xx_wdt_enable(void) { printk(KERN_DEBUG DRV_NAME ": enabling watchdog timer\n"); ar71xx_wdt_keepalive(); ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR); } static void inline ar71xx_wdt_disable(void) { printk(KERN_DEBUG DRV_NAME ": disabling watchdog timer\n"); ar71xx_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE); } static int ar71xx_wdt_set_timeout(int val) { if (val < 1 || val > max_timeout) return -EINVAL; wdt_timeout = val; ar71xx_wdt_keepalive(); printk(KERN_DEBUG DRV_NAME ": timeout=%d secs\n", wdt_timeout); return 0; } static int ar71xx_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags)) return -EBUSY; clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); ar71xx_wdt_enable(); return nonseekable_open(inode, file); } static int ar71xx_wdt_release(struct inode *inode, struct file *file) { if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags)) { ar71xx_wdt_disable(); } else { printk(KERN_CRIT DRV_NAME ": device closed unexpectedly, " "watchdog timer will not stop!\n"); } clear_bit(WDT_FLAGS_BUSY, &wdt_flags); clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); return 0; } static ssize_t ar71xx_wdt_write(struct file *file, const char *data, size_t len, loff_t *ppos) { if (len) { if (!nowayout) { size_t i; clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); for (i = 0; i != len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') set_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); } } ar71xx_wdt_keepalive(); } return len; } static struct watchdog_info ar71xx_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_CARDRESET, .firmware_version = 0, .identity = "AR71XX watchdog", }; static int ar71xx_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int t; int ret; switch (cmd) { case WDIOC_GETSUPPORT: ret = copy_to_user((struct watchdog_info *)arg, &ar71xx_wdt_info, sizeof(&ar71xx_wdt_info)) ? -EFAULT : 0; break; case WDIOC_GETSTATUS: ret = put_user(0, (int *)arg) ? -EFAULT : 0; break; case WDIOC_GETBOOTSTATUS: ret = put_user(boot_status, (int *)arg) ? -EFAULT : 0; break; case WDIOC_KEEPALIVE: ar71xx_wdt_keepalive(); ret = 0; break; case WDIOC_SETTIMEOUT: ret = get_user(t, (int *)arg) ? -EFAULT : 0; if (ret) break; ret = ar71xx_wdt_set_timeout(t); if (ret) break; /* fallthrough */ case WDIOC_GETTIMEOUT: ret = put_user(wdt_timeout, (int *)arg) ? -EFAULT : 0; break; default: ret = -ENOTTY; break; } return ret; } static const struct file_operations ar71xx_wdt_fops = { .owner = THIS_MODULE, .write = ar71xx_wdt_write, .ioctl = ar71xx_wdt_ioctl, .open = ar71xx_wdt_open, .release = ar71xx_wdt_release, }; static struct miscdevice ar71xx_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &ar71xx_wdt_fops, }; static int __devinit ar71xx_wdt_probe(struct platform_device *pdev) { int ret; max_timeout = (0xfffffffful / ar71xx_ahb_freq); wdt_timeout = (max_timeout < WDT_TIMEOUT) ? max_timeout : WDT_TIMEOUT; boot_status = (ar71xx_reset_rr(AR71XX_RESET_REG_WDOG_CTRL) & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0; ret = misc_register(&ar71xx_wdt_miscdev); if (ret) goto err_out; printk(KERN_INFO DRV_DESC " version " DRV_VERSION "\n"); printk(KERN_DEBUG DRV_NAME ": timeout=%d secs (max=%d)\n", wdt_timeout, max_timeout); return 0; err_out: return ret; } static int __devexit ar71xx_wdt_remove(struct platform_device *pdev) { misc_deregister(&ar71xx_wdt_miscdev); return 0; } static struct platform_driver ar71xx_wdt_driver = { .probe = ar71xx_wdt_probe, .remove = __devexit_p(ar71xx_wdt_remove), .driver = { .name = DRV_NAME, .owner = THIS_MODULE, }, }; static int __init ar71xx_wdt_init(void) { return platform_driver_register(&ar71xx_wdt_driver); } module_init(ar71xx_wdt_init); static void __exit ar71xx_wdt_exit(void) { platform_driver_unregister(&ar71xx_wdt_driver); } module_exit(ar71xx_wdt_exit); MODULE_DESCRIPTION(DRV_DESC); MODULE_VERSION(DRV_VERSION); MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org"); MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:" DRV_NAME); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);