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+/*
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+ * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
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+ *
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+ * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
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+ * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
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+ *
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+ * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
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+ * Author: Deepak Saxena <dsaxena@plexity.net>
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+ * Copyright 2004 (c) MontaVista, Software, Inc.
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+ *
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+ * which again was based on sa1100 driver,
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+ * Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
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+ *
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+ * This program is free software; you can redistribute it and/or modify it
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+ * under the terms of the GNU General Public License version 2 as published
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+ * by the Free Software Foundation.
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+ *
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+ */
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+
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+#include <linux/bitops.h>
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+#include <linux/errno.h>
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+#include <linux/fs.h>
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+#include <linux/init.h>
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+#include <linux/kernel.h>
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+#include <linux/miscdevice.h>
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+#include <linux/module.h>
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+#include <linux/moduleparam.h>
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+#include <linux/platform_device.h>
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+#include <linux/types.h>
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+#include <linux/watchdog.h>
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+#include <linux/clk.h>
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+#include <linux/err.h>
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+
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+#include <asm/mach-ath79/ath79.h>
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+#include <asm/mach-ath79/ar71xx_regs.h>
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+
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+#define DRIVER_NAME "ath79-wdt"
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+
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+#define WDT_TIMEOUT 15 /* seconds */
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+
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+#define WDOG_CTRL_LAST_RESET BIT(31)
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+#define WDOG_CTRL_ACTION_MASK 3
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+#define WDOG_CTRL_ACTION_NONE 0 /* no action */
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+#define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */
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+#define WDOG_CTRL_ACTION_NMI 2 /* NMI */
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+#define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */
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+
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+static int nowayout = WATCHDOG_NOWAYOUT;
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+module_param(nowayout, int, 0);
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+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
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+ "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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+
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+static int timeout = WDT_TIMEOUT;
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+module_param(timeout, int, 0);
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+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
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+ "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
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+
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+static unsigned long wdt_flags;
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+
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+#define WDT_FLAGS_BUSY 0
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+#define WDT_FLAGS_EXPECT_CLOSE 1
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+
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+static struct clk *wdt_clk;
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+static unsigned long wdt_freq;
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+static int boot_status;
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+static int max_timeout;
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+
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+static inline void ath79_wdt_keepalive(void)
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+{
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+ ath79_reset_wr(AR71XX_RESET_REG_WDOG, wdt_freq * timeout);
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+}
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+
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+static inline void ath79_wdt_enable(void)
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+{
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+ ath79_wdt_keepalive();
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+ ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
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+}
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+
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+static inline void ath79_wdt_disable(void)
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+{
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+ ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
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+}
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+
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+static int ath79_wdt_set_timeout(int val)
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+{
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+ if (val < 1 || val > max_timeout)
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+ return -EINVAL;
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+
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+ timeout = val;
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+ ath79_wdt_keepalive();
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+
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+ return 0;
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+}
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+
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+static int ath79_wdt_open(struct inode *inode, struct file *file)
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+{
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+ if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
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+ return -EBUSY;
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+
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+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
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+ ath79_wdt_enable();
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+
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+ return nonseekable_open(inode, file);
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+}
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+
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+static int ath79_wdt_release(struct inode *inode, struct file *file)
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+{
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+ if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
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+ ath79_wdt_disable();
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+ else {
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+ pr_crit(DRIVER_NAME ": device closed unexpectedly, "
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+ "watchdog timer will not stop!\n");
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+ ath79_wdt_keepalive();
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+ }
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+
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+ clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
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+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
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+
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+ return 0;
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+}
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+
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+static ssize_t ath79_wdt_write(struct file *file, const char *data,
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+ size_t len, loff_t *ppos)
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+{
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+ if (len) {
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+ if (!nowayout) {
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+ size_t i;
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+
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+ clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
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+
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+ for (i = 0; i != len; i++) {
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+ char c;
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+
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+ if (get_user(c, data + i))
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+ return -EFAULT;
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+
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+ if (c == 'V')
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+ set_bit(WDT_FLAGS_EXPECT_CLOSE,
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+ &wdt_flags);
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+ }
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+ }
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+
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+ ath79_wdt_keepalive();
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+ }
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+
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+ return len;
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+}
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+
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+static const struct watchdog_info ath79_wdt_info = {
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+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
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+ WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
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+ .firmware_version = 0,
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+ .identity = "ATH79 watchdog",
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+};
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+
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+static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
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+ unsigned long arg)
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+{
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+ void __user *argp = (void __user *)arg;
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+ int __user *p = argp;
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+ int err;
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+ int t;
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+
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+ switch (cmd) {
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+ case WDIOC_GETSUPPORT:
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+ err = copy_to_user(argp, &ath79_wdt_info,
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+ sizeof(ath79_wdt_info)) ? -EFAULT : 0;
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+ break;
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+
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+ case WDIOC_GETSTATUS:
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+ err = put_user(0, p);
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+ break;
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+
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+ case WDIOC_GETBOOTSTATUS:
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+ err = put_user(boot_status, p);
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+ break;
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+
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+ case WDIOC_KEEPALIVE:
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+ ath79_wdt_keepalive();
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+ err = 0;
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+ break;
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+
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+ case WDIOC_SETTIMEOUT:
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+ err = get_user(t, p);
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+ if (err)
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+ break;
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+
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+ err = ath79_wdt_set_timeout(t);
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+ if (err)
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+ break;
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+
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+ /* fallthrough */
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+ case WDIOC_GETTIMEOUT:
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+ err = put_user(timeout, p);
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+ break;
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+
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+ default:
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+ err = -ENOTTY;
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+ break;
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+ }
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+
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+ return err;
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+}
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+
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+static const struct file_operations ath79_wdt_fops = {
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+ .owner = THIS_MODULE,
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+ .llseek = no_llseek,
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+ .write = ath79_wdt_write,
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+ .unlocked_ioctl = ath79_wdt_ioctl,
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+ .open = ath79_wdt_open,
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+ .release = ath79_wdt_release,
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+};
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+
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+static struct miscdevice ath79_wdt_miscdev = {
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+ .minor = WATCHDOG_MINOR,
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+ .name = "watchdog",
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+ .fops = &ath79_wdt_fops,
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+};
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+
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+static int __devinit ath79_wdt_probe(struct platform_device *pdev)
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+{
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+ u32 ctrl;
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+ int err;
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+
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+ wdt_clk = clk_get(&pdev->dev, "wdt");
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+ if (IS_ERR(wdt_clk))
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+ return PTR_ERR(wdt_clk);
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+
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+ err = clk_enable(wdt_clk);
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+ if (err)
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+ goto err_clk_put;
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+
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+ wdt_freq = clk_get_rate(wdt_clk);
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+ if (!wdt_freq) {
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+ err = -EINVAL;
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+ goto err_clk_disable;
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+ }
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+
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+ max_timeout = (0xfffffffful / wdt_freq);
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+ if (timeout < 1 || timeout > max_timeout) {
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+ timeout = max_timeout;
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+ dev_info(&pdev->dev,
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+ "timeout value must be 0 < timeout < %d, using %d\n",
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+ max_timeout, timeout);
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+ }
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+
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+ ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
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+ boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
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+
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+ err = misc_register(&ath79_wdt_miscdev);
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+ if (err) {
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+ dev_err(&pdev->dev,
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+ "unable to register misc device, err=%d\n", err);
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+ goto err_clk_disable;
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+ }
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+
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+ return 0;
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+
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+err_clk_disable:
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+ clk_disable(wdt_clk);
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+err_clk_put:
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+ clk_put(wdt_clk);
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+ return err;
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+}
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+
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+static int __devexit ath79_wdt_remove(struct platform_device *pdev)
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+{
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+ misc_deregister(&ath79_wdt_miscdev);
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+ clk_disable(wdt_clk);
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+ clk_put(wdt_clk);
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+ return 0;
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+}
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+
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+static void ath97_wdt_shutdown(struct platform_device *pdev)
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+{
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+ ath79_wdt_disable();
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+}
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+
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+static struct platform_driver ath79_wdt_driver = {
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+ .remove = __devexit_p(ath79_wdt_remove),
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+ .shutdown = ath97_wdt_shutdown,
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+ .driver = {
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+ .name = DRIVER_NAME,
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+ .owner = THIS_MODULE,
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+ },
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+};
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+
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+static int __init ath79_wdt_init(void)
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+{
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+ return platform_driver_probe(&ath79_wdt_driver, ath79_wdt_probe);
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+}
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+module_init(ath79_wdt_init);
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+
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+static void __exit ath79_wdt_exit(void)
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+{
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+ platform_driver_unregister(&ath79_wdt_driver);
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+}
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+module_exit(ath79_wdt_exit);
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+
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+MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
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+MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
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+MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
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+MODULE_LICENSE("GPL v2");
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+MODULE_ALIAS("platform:" DRIVER_NAME);
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+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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