+From 3466449c8f455da0cb646231602e6af16190f592 Mon Sep 17 00:00:00 2001
+From: John Crispin <blogic@openwrt.org>
+Date: Thu, 5 May 2011 23:00:23 +0200
+Subject: [PATCH 13/13] MIPS: Lantiq: Add watchdog support
+
+This patch adds the driver for the watchdog found inside the Lantiq SoC family.
+
+Signed-off-by: John Crispin <blogic@openwrt.org>
+Signed-off-by: Ralph Hempel <ralph.hempel@lantiq.com>
+Cc: Wim Van Sebroeck <wim@iguana.be>
+Cc: linux-mips@linux-mips.org
+Cc: linux-watchdog@vger.kernel.org
+Patchwork: https://patchwork.linux-mips.org/patch/2327/
+Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
+---
+ drivers/watchdog/Kconfig | 6 +
+ drivers/watchdog/Makefile | 1 +
+ drivers/watchdog/lantiq_wdt.c | 261 +++++++++++++++++++++++++++++++++++++++++
+ 3 files changed, 268 insertions(+), 0 deletions(-)
+ create mode 100644 drivers/watchdog/lantiq_wdt.c
+
+--- a/drivers/watchdog/Kconfig
++++ b/drivers/watchdog/Kconfig
+@@ -850,6 +850,12 @@
+ help
+ Hardware driver for the built-in watchdog timer on TXx9 MIPS SoCs.
+
++config LANTIQ_WDT
++ tristate "Lantiq SoC watchdog"
++ depends on LANTIQ
++ help
++ Hardware driver for the Lantiq SoC Watchdog Timer.
++
+ # PARISC Architecture
+
+ # POWERPC Architecture
+--- a/drivers/watchdog/Makefile
++++ b/drivers/watchdog/Makefile
+@@ -113,6 +113,7 @@
+ obj-$(CONFIG_SIBYTE_WDOG) += sb_wdog.o
+ obj-$(CONFIG_AR7_WDT) += ar7_wdt.o
+ obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
++obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o
+
+ # PARISC Architecture
+
+--- /dev/null
++++ b/drivers/watchdog/lantiq_wdt.c
+@@ -0,0 +1,261 @@
++/*
++ * 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.
++ *
++ * Copyright (C) 2010 John Crispin <blogic@openwrt.org>
++ * Based on EP93xx wdt driver
++ */
++
++#include <linux/module.h>
++#include <linux/fs.h>
++#include <linux/miscdevice.h>
++#include <linux/watchdog.h>
++#include <linux/platform_device.h>
++#include <linux/uaccess.h>
++#include <linux/clk.h>
++#include <linux/io.h>
++
++#include <lantiq.h>
++
++/* Section 3.4 of the datasheet
++ * The password sequence protects the WDT control register from unintended
++ * write actions, which might cause malfunction of the WDT.
++ *
++ * essentially the following two magic passwords need to be written to allow
++ * IO access to the WDT core
++ */
++#define LTQ_WDT_PW1 0x00BE0000
++#define LTQ_WDT_PW2 0x00DC0000
++
++#define LTQ_WDT_CR 0x0 /* watchdog control register */
++#define LTQ_WDT_SR 0x8 /* watchdog status register */
++
++#define LTQ_WDT_SR_EN (0x1 << 31) /* enable bit */
++#define LTQ_WDT_SR_PWD (0x3 << 26) /* turn on power */
++#define LTQ_WDT_SR_CLKDIV (0x3 << 24) /* turn on clock and set */
++ /* divider to 0x40000 */
++#define LTQ_WDT_DIVIDER 0x40000
++#define LTQ_MAX_TIMEOUT ((1 << 16) - 1) /* the reload field is 16 bit */
++
++static int nowayout = WATCHDOG_NOWAYOUT;
++
++static void __iomem *ltq_wdt_membase;
++static unsigned long ltq_io_region_clk_rate;
++
++static unsigned long ltq_wdt_bootstatus;
++static unsigned long ltq_wdt_in_use;
++static int ltq_wdt_timeout = 30;
++static int ltq_wdt_ok_to_close;
++
++static void
++ltq_wdt_enable(void)
++{
++ ltq_wdt_timeout = ltq_wdt_timeout *
++ (ltq_io_region_clk_rate / LTQ_WDT_DIVIDER) + 0x1000;
++ if (ltq_wdt_timeout > LTQ_MAX_TIMEOUT)
++ ltq_wdt_timeout = LTQ_MAX_TIMEOUT;
++
++ /* write the first password magic */
++ ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
++ /* write the second magic plus the configuration and new timeout */
++ ltq_w32(LTQ_WDT_SR_EN | LTQ_WDT_SR_PWD | LTQ_WDT_SR_CLKDIV |
++ LTQ_WDT_PW2 | ltq_wdt_timeout, ltq_wdt_membase + LTQ_WDT_CR);
++}
++
++static void
++ltq_wdt_disable(void)
++{
++ /* write the first password magic */
++ ltq_w32(LTQ_WDT_PW1, ltq_wdt_membase + LTQ_WDT_CR);
++ /* write the second password magic with no config
++ * this turns the watchdog off
++ */
++ ltq_w32(LTQ_WDT_PW2, ltq_wdt_membase + LTQ_WDT_CR);
++}
++
++static ssize_t
++ltq_wdt_write(struct file *file, const char __user *data,
++ size_t len, loff_t *ppos)
++{
++ if (len) {
++ if (!nowayout) {
++ size_t i;
++
++ ltq_wdt_ok_to_close = 0;
++ for (i = 0; i != len; i++) {
++ char c;
++
++ if (get_user(c, data + i))
++ return -EFAULT;
++ if (c == 'V')
++ ltq_wdt_ok_to_close = 1;
++ else
++ ltq_wdt_ok_to_close = 0;
++ }
++ }
++ ltq_wdt_enable();
++ }
++
++ return len;
++}
++
++static struct watchdog_info ident = {
++ .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
++ WDIOF_CARDRESET,
++ .identity = "ltq_wdt",
++};
++
++static long
++ltq_wdt_ioctl(struct file *file,
++ unsigned int cmd, unsigned long arg)
++{
++ int ret = -ENOTTY;
++
++ switch (cmd) {
++ case WDIOC_GETSUPPORT:
++ ret = copy_to_user((struct watchdog_info __user *)arg, &ident,
++ sizeof(ident)) ? -EFAULT : 0;
++ break;
++
++ case WDIOC_GETBOOTSTATUS:
++ ret = put_user(ltq_wdt_bootstatus, (int __user *)arg);
++ break;
++
++ case WDIOC_GETSTATUS:
++ ret = put_user(0, (int __user *)arg);
++ break;
++
++ case WDIOC_SETTIMEOUT:
++ ret = get_user(ltq_wdt_timeout, (int __user *)arg);
++ if (!ret)
++ ltq_wdt_enable();
++ /* intentional drop through */
++ case WDIOC_GETTIMEOUT:
++ ret = put_user(ltq_wdt_timeout, (int __user *)arg);
++ break;
++
++ case WDIOC_KEEPALIVE:
++ ltq_wdt_enable();
++ ret = 0;
++ break;
++ }
++ return ret;
++}
++
++static int
++ltq_wdt_open(struct inode *inode, struct file *file)
++{
++ if (test_and_set_bit(0, <q_wdt_in_use))
++ return -EBUSY;
++ ltq_wdt_in_use = 1;
++ ltq_wdt_enable();
++
++ return nonseekable_open(inode, file);
++}
++
++static int
++ltq_wdt_release(struct inode *inode, struct file *file)
++{
++ if (ltq_wdt_ok_to_close)
++ ltq_wdt_disable();
++ else
++ pr_err("ltq_wdt: watchdog closed without warning\n");
++ ltq_wdt_ok_to_close = 0;
++ clear_bit(0, <q_wdt_in_use);
++
++ return 0;
++}
++
++static const struct file_operations ltq_wdt_fops = {
++ .owner = THIS_MODULE,
++ .write = ltq_wdt_write,
++ .unlocked_ioctl = ltq_wdt_ioctl,
++ .open = ltq_wdt_open,
++ .release = ltq_wdt_release,
++ .llseek = no_llseek,
++};
++
++static struct miscdevice ltq_wdt_miscdev = {
++ .minor = WATCHDOG_MINOR,
++ .name = "watchdog",
++ .fops = <q_wdt_fops,
++};
++
++static int __init
++ltq_wdt_probe(struct platform_device *pdev)
++{
++ struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
++ struct clk *clk;
++
++ if (!res) {
++ dev_err(&pdev->dev, "cannot obtain I/O memory region");
++ return -ENOENT;
++ }
++ res = devm_request_mem_region(&pdev->dev, res->start,
++ resource_size(res), dev_name(&pdev->dev));
++ if (!res) {
++ dev_err(&pdev->dev, "cannot request I/O memory region");
++ return -EBUSY;
++ }
++ ltq_wdt_membase = devm_ioremap_nocache(&pdev->dev, res->start,
++ resource_size(res));
++ if (!ltq_wdt_membase) {
++ dev_err(&pdev->dev, "cannot remap I/O memory region\n");
++ return -ENOMEM;
++ }
++
++ /* we do not need to enable the clock as it is always running */
++ clk = clk_get(&pdev->dev, "io");
++ WARN_ON(!clk);
++ ltq_io_region_clk_rate = clk_get_rate(clk);
++ clk_put(clk);
++
++ if (ltq_reset_cause() == LTQ_RST_CAUSE_WDTRST)
++ ltq_wdt_bootstatus = WDIOF_CARDRESET;
++
++ return misc_register(<q_wdt_miscdev);
++}
++
++static int __devexit
++ltq_wdt_remove(struct platform_device *pdev)
++{
++ misc_deregister(<q_wdt_miscdev);
++
++ if (ltq_wdt_membase)
++ iounmap(ltq_wdt_membase);
++
++ return 0;
++}
++
++
++static struct platform_driver ltq_wdt_driver = {
++ .remove = __devexit_p(ltq_wdt_remove),
++ .driver = {
++ .name = "ltq_wdt",
++ .owner = THIS_MODULE,
++ },
++};
++
++static int __init
++init_ltq_wdt(void)
++{
++ return platform_driver_probe(<q_wdt_driver, ltq_wdt_probe);
++}
++
++static void __exit
++exit_ltq_wdt(void)
++{
++ return platform_driver_unregister(<q_wdt_driver);
++}
++
++module_init(init_ltq_wdt);
++module_exit(exit_ltq_wdt);
++
++module_param(nowayout, int, 0);
++MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
++
++MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
++MODULE_DESCRIPTION("Lantiq SoC Watchdog");
++MODULE_LICENSE("GPL");
++MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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