/* * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer. * * Copyright (C) 2008-2011 Gabor Juhos * Copyright (C) 2008 Imre Kaloz * * This driver was based on: drivers/watchdog/ixp4xx_wdt.c * Author: Deepak Saxena * Copyright 2004 (c) MontaVista, Software, Inc. * * which again was based on sa1100 driver, * Copyright (C) 2000 Oleg Drokin * * 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. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DRIVER_NAME "ath79-wdt" #define WDT_TIMEOUT 15 /* seconds */ #define WDOG_CTRL_LAST_RESET BIT(31) #define WDOG_CTRL_ACTION_MASK 3 #define WDOG_CTRL_ACTION_NONE 0 /* no action */ #define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */ #define WDOG_CTRL_ACTION_NMI 2 /* NMI */ #define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */ 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 int timeout = WDT_TIMEOUT; module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds " "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)"); static unsigned long wdt_flags; #define WDT_FLAGS_BUSY 0 #define WDT_FLAGS_EXPECT_CLOSE 1 static struct clk *wdt_clk; static unsigned long wdt_freq; static int boot_status; static int max_timeout; static inline void ath79_wdt_keepalive(void) { ath79_reset_wr(AR71XX_RESET_REG_WDOG, wdt_freq * timeout); /* flush write */ ath79_reset_rr(AR71XX_RESET_REG_WDOG); } static inline void ath79_wdt_enable(void) { ath79_wdt_keepalive(); ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR); /* flush write */ ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL); } static inline void ath79_wdt_disable(void) { ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE); /* flush write */ ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL); } static int ath79_wdt_set_timeout(int val) { if (val < 1 || val > max_timeout) return -EINVAL; timeout = val; ath79_wdt_keepalive(); return 0; } static int ath79_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); ath79_wdt_enable(); return nonseekable_open(inode, file); } static int ath79_wdt_release(struct inode *inode, struct file *file) { if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags)) ath79_wdt_disable(); else { pr_crit("device closed unexpectedly, watchdog timer will not stop!\n"); ath79_wdt_keepalive(); } clear_bit(WDT_FLAGS_BUSY, &wdt_flags); clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); return 0; } static ssize_t ath79_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); } } ath79_wdt_keepalive(); } return len; } static const struct watchdog_info ath79_wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_CARDRESET, .firmware_version = 0, .identity = "ATH79 watchdog", }; static long ath79_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; int err; int t; switch (cmd) { case WDIOC_GETSUPPORT: err = copy_to_user(argp, &ath79_wdt_info, sizeof(ath79_wdt_info)) ? -EFAULT : 0; break; case WDIOC_GETSTATUS: err = put_user(0, p); break; case WDIOC_GETBOOTSTATUS: err = put_user(boot_status, p); break; case WDIOC_KEEPALIVE: ath79_wdt_keepalive(); err = 0; break; case WDIOC_SETTIMEOUT: err = get_user(t, p); if (err) break; err = ath79_wdt_set_timeout(t); if (err) break; /* fallthrough */ case WDIOC_GETTIMEOUT: err = put_user(timeout, p); break; default: err = -ENOTTY; break; } return err; } static const struct file_operations ath79_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = ath79_wdt_write, .unlocked_ioctl = ath79_wdt_ioctl, .open = ath79_wdt_open, .release = ath79_wdt_release, }; static struct miscdevice ath79_wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &ath79_wdt_fops, }; static int ath79_wdt_probe(struct platform_device *pdev) { u32 ctrl; int err; wdt_clk = devm_clk_get(&pdev->dev, "wdt"); if (IS_ERR(wdt_clk)) return PTR_ERR(wdt_clk); err = clk_enable(wdt_clk); if (err) return err; wdt_freq = clk_get_rate(wdt_clk); if (!wdt_freq) { err = -EINVAL; goto err_clk_disable; } max_timeout = (0xfffffffful / wdt_freq); if (timeout < 1 || timeout > max_timeout) { timeout = max_timeout; dev_info(&pdev->dev, "timeout value must be 0 < timeout < %d, using %d\n", max_timeout, timeout); } ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL); boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0; err = misc_register(&ath79_wdt_miscdev); if (err) { dev_err(&pdev->dev, "unable to register misc device, err=%d\n", err); goto err_clk_disable; } return 0; err_clk_disable: clk_disable(wdt_clk); return err; } static int ath79_wdt_remove(struct platform_device *pdev) { misc_deregister(&ath79_wdt_miscdev); clk_disable(wdt_clk); return 0; } static void ath97_wdt_shutdown(struct platform_device *pdev) { ath79_wdt_disable(); } static struct platform_driver ath79_wdt_driver = { .probe = ath79_wdt_probe, .remove = ath79_wdt_remove, .shutdown = ath97_wdt_shutdown, .driver = { .name = DRIVER_NAME, .owner = THIS_MODULE, }, }; module_platform_driver(ath79_wdt_driver); MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver"); MODULE_AUTHOR("Gabor Juhos