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@@ -0,0 +1,276 @@
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+/*
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+ * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs
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+ *
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+ * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
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+ *
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+ * This program is free software; you can redistribute it and/or modify
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+ * it under the terms of the GNU General Public License version 2 as
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+ * published by the Free Software Foundation.
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+ */
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+#include <linux/module.h>
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+#include <linux/moduleparam.h>
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+#include <linux/types.h>
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+#include <linux/miscdevice.h>
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+#include <linux/watchdog.h>
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+#include <linux/fs.h>
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+#include <linux/reboot.h>
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+#include <linux/init.h>
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+#include <linux/uaccess.h>
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+#include <linux/platform_device.h>
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+#include <linux/clk.h>
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+#include <linux/err.h>
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+#include <linux/io.h>
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+#include <asm/txx9tmr.h>
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+
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+#define TIMER_MARGIN 60 /* Default is 60 seconds */
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+
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+static int timeout = TIMER_MARGIN; /* in seconds */
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+module_param(timeout, int, 0);
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+MODULE_PARM_DESC(timeout,
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+ "Watchdog timeout in seconds. "
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+ "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "
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+ "default=" __MODULE_STRING(TIMER_MARGIN) ")");
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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,
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+ "Watchdog cannot be stopped once started "
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+ "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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+
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+#define WD_TIMER_CCD 7 /* 1/256 */
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+#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))
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+#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)
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+
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+static unsigned long txx9wdt_alive;
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+static int expect_close;
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+static struct txx9_tmr_reg __iomem *txx9wdt_reg;
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+static struct clk *txx9_imclk;
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+
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+static void txx9wdt_ping(void)
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+{
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+ __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
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+}
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+
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+static void txx9wdt_start(void)
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+{
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+ __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra);
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+ __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);
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+ __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */
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+ __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,
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+ &txx9wdt_reg->tcr);
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+ __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);
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+}
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+
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+static void txx9wdt_stop(void)
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+{
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+ __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);
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+ __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,
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+ &txx9wdt_reg->tcr);
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+}
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+
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+static int txx9wdt_open(struct inode *inode, struct file *file)
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+{
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+ if (test_and_set_bit(0, &txx9wdt_alive))
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+ return -EBUSY;
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+
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+ if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) {
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+ clear_bit(0, &txx9wdt_alive);
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+ return -EBUSY;
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+ }
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+
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+ if (nowayout)
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+ __module_get(THIS_MODULE);
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+
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+ txx9wdt_start();
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+ return nonseekable_open(inode, file);
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+}
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+
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+static int txx9wdt_release(struct inode *inode, struct file *file)
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+{
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+ if (expect_close)
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+ txx9wdt_stop();
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+ else {
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+ printk(KERN_CRIT "txx9wdt: "
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+ "Unexpected close, not stopping watchdog!\n");
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+ txx9wdt_ping();
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+ }
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+ clear_bit(0, &txx9wdt_alive);
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+ expect_close = 0;
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+ return 0;
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+}
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+
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+static ssize_t txx9wdt_write(struct file *file, const char __user *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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+ expect_close = 0;
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+ for (i = 0; i != len; i++) {
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+ char c;
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+ if (get_user(c, data + i))
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+ return -EFAULT;
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+ if (c == 'V')
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+ expect_close = 1;
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+ }
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+ }
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+ txx9wdt_ping();
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+ }
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+ return len;
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+}
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+
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+static int txx9wdt_ioctl(struct inode *inode, struct file *file,
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+ unsigned int cmd, 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 new_timeout;
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+ static struct watchdog_info ident = {
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+ .options = WDIOF_SETTIMEOUT |
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+ WDIOF_KEEPALIVEPING |
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+ WDIOF_MAGICCLOSE,
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+ .firmware_version = 0,
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+ .identity = "Hardware Watchdog for TXx9",
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+ };
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+
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+ switch (cmd) {
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+ default:
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+ return -ENOTTY;
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+ case WDIOC_GETSUPPORT:
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+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
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+ case WDIOC_GETSTATUS:
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+ case WDIOC_GETBOOTSTATUS:
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+ return put_user(0, p);
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+ case WDIOC_KEEPALIVE:
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+ txx9wdt_ping();
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+ return 0;
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+ case WDIOC_SETTIMEOUT:
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+ if (get_user(new_timeout, p))
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+ return -EFAULT;
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+ if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT)
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+ return -EINVAL;
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+ timeout = new_timeout;
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+ txx9wdt_stop();
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+ txx9wdt_start();
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+ /* Fall */
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+ case WDIOC_GETTIMEOUT:
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+ return put_user(timeout, p);
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+ }
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+}
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+
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+static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code,
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+ void *unused)
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+{
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+ if (code == SYS_DOWN || code == SYS_HALT)
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+ txx9wdt_stop();
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+ return NOTIFY_DONE;
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+}
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+
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+static const struct file_operations txx9wdt_fops = {
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+ .owner = THIS_MODULE,
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+ .llseek = no_llseek,
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+ .write = txx9wdt_write,
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+ .ioctl = txx9wdt_ioctl,
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+ .open = txx9wdt_open,
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+ .release = txx9wdt_release,
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+};
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+
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+static struct miscdevice txx9wdt_miscdev = {
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+ .minor = WATCHDOG_MINOR,
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+ .name = "watchdog",
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+ .fops = &txx9wdt_fops,
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+};
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+
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+static struct notifier_block txx9wdt_notifier = {
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+ .notifier_call = txx9wdt_notify_sys
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+};
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+
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+static int __init txx9wdt_probe(struct platform_device *dev)
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+{
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+ struct resource *res;
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+ int ret;
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+
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+ txx9_imclk = clk_get(NULL, "imbus_clk");
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+ if (IS_ERR(txx9_imclk)) {
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+ ret = PTR_ERR(txx9_imclk);
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+ txx9_imclk = NULL;
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+ goto exit;
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+ }
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+ ret = clk_enable(txx9_imclk);
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+ if (ret) {
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+ clk_put(txx9_imclk);
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+ txx9_imclk = NULL;
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+ goto exit;
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+ }
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+
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+ res = platform_get_resource(dev, IORESOURCE_MEM, 0);
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+ if (!res)
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+ goto exit_busy;
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+ if (!devm_request_mem_region(&dev->dev,
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+ res->start, res->end - res->start + 1,
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+ "txx9wdt"))
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+ goto exit_busy;
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+ txx9wdt_reg = devm_ioremap(&dev->dev,
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+ res->start, res->end - res->start + 1);
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+ if (!txx9wdt_reg)
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+ goto exit_busy;
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+
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+ ret = register_reboot_notifier(&txx9wdt_notifier);
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+ if (ret)
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+ goto exit;
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+
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+ ret = misc_register(&txx9wdt_miscdev);
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+ if (ret) {
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+ unregister_reboot_notifier(&txx9wdt_notifier);
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+ goto exit;
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+ }
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+
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+ printk(KERN_INFO "Hardware Watchdog Timer for TXx9: "
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+ "timeout=%d sec (max %ld) (nowayout= %d)\n",
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+ timeout, WD_MAX_TIMEOUT, nowayout);
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+
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+ return 0;
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+exit_busy:
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+ ret = -EBUSY;
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+exit:
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+ if (txx9_imclk) {
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+ clk_disable(txx9_imclk);
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+ clk_put(txx9_imclk);
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+ }
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+ return ret;
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+}
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+
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+static int __exit txx9wdt_remove(struct platform_device *dev)
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+{
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+ misc_deregister(&txx9wdt_miscdev);
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+ unregister_reboot_notifier(&txx9wdt_notifier);
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+ clk_disable(txx9_imclk);
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+ clk_put(txx9_imclk);
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+ return 0;
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+}
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+
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+static struct platform_driver txx9wdt_driver = {
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+ .remove = __exit_p(txx9wdt_remove),
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+ .driver = {
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+ .name = "txx9wdt",
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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 watchdog_init(void)
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+{
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+ return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe);
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+}
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+
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+static void __exit watchdog_exit(void)
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+{
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+ platform_driver_unregister(&txx9wdt_driver);
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+}
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+
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+module_init(watchdog_init);
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+module_exit(watchdog_exit);
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+
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+MODULE_DESCRIPTION("TXx9 Watchdog Driver");
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+MODULE_LICENSE("GPL");
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+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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