From ed8c2d720954efc5a440912292ed11da2f50aaea Mon Sep 17 00:00:00 2001
From: popcornmix <popcornmix@gmail.com>
Date: Tue, 17 Jan 2012 19:20:57 +0000
Subject: [PATCH 3/7] bcm2708 watchdog driver

Signed-off-by: popcornmix <popcornmix@gmail.com>
---
 drivers/watchdog/Kconfig        |    6 +
 drivers/watchdog/Makefile       |    1 +
 drivers/watchdog/bcm2708_wdog.c |  385 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 392 insertions(+), 0 deletions(-)
 create mode 100644 drivers/watchdog/bcm2708_wdog.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 86b0735..7675ebc 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -348,6 +348,12 @@ config IMX2_WDT
 	  To compile this driver as a module, choose M here: the
 	  module will be called imx2_wdt.
 
+config BCM2708_WDT
+	tristate "BCM2708 Watchdog"
+	depends on ARCH_BCM2708
+	help
+	  Enables BCM2708 watchdog support.
+
 # AVR32 Architecture
 
 config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 55bd574..803f0bc 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -54,6 +54,7 @@ obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
 obj-$(CONFIG_ADX_WATCHDOG) += adx_wdt.o
 obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
 obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
+obj-$(CONFIG_BCM2708_WDT) += bcm2708_wdog.o
 
 # AVR32 Architecture
 obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/bcm2708_wdog.c b/drivers/watchdog/bcm2708_wdog.c
new file mode 100644
index 0000000..dd33c35
--- /dev/null
+++ b/drivers/watchdog/bcm2708_wdog.c
@@ -0,0 +1,385 @@
+/*
+ *	Broadcom BCM2708 watchdog driver.
+ *
+ *	(c) Copyright 2010 Broadcom Europe Ltd
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ *      BCM2708 watchdog driver. Loosely based on wdt driver.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <mach/platform.h>
+
+#include <asm/system.h>
+
+#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
+#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
+
+static unsigned long wdog_is_open;
+static uint32_t wdog_ticks;	       /* Ticks to load into wdog timer */
+static char expect_close;
+
+/*
+ *	Module parameters
+ */
+
+#define WD_TIMO 10		       /* Default heartbeat = 60 seconds */
+static int heartbeat = WD_TIMO;	       /* Heartbeat in seconds */
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+	"Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
+				__MODULE_STRING(WD_TIMO) ")");
+
+static int nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, int, 0);
+MODULE_PARM_DESC(nowayout,
+	"Watchdog cannot be stopped once started (default="
+				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static DEFINE_SPINLOCK(wdog_lock);
+
+/**
+ *	Start the watchdog driver.
+ */
+
+static int wdog_start(unsigned long timeout)
+{
+	uint32_t cur;
+	unsigned long flags;
+	spin_lock_irqsave(&wdog_lock, flags);
+
+	/* enable the watchdog */
+	iowrite32(PM_PASSWORD | (timeout & PM_WDOG_TIME_SET), 
+		  __io_address(PM_WDOG));
+	cur = ioread32(__io_address(PM_RSTC));
+	iowrite32(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
+		  PM_RSTC_WRCFG_FULL_RESET, __io_address(PM_RSTC));
+
+	spin_unlock_irqrestore(&wdog_lock, flags);
+	return 0;
+}
+
+/**
+ *	Stop the watchdog driver.
+ */
+
+static int wdog_stop(void)
+{
+	iowrite32(PM_PASSWORD | PM_RSTC_RESET, __io_address(PM_RSTC));
+	printk(KERN_INFO "watchdog stopped\n");
+	return 0;
+}
+
+/**
+ *	Reload counter one with the watchdog heartbeat. We don't bother
+ *	reloading the cascade counter.
+ */
+
+static void wdog_ping(void)
+{
+	wdog_start(wdog_ticks);
+}
+
+/**
+ *	@t:		the new heartbeat value that needs to be set.
+ *
+ *	Set a new heartbeat value for the watchdog device. If the heartbeat
+ *	value is incorrect we keep the old value and return -EINVAL. If
+ *	successful we return 0.
+ */
+
+static int wdog_set_heartbeat(int t)
+{
+	if (t < 1 || t > WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET))
+		return -EINVAL;
+
+	heartbeat = t;
+	wdog_ticks = SECS_TO_WDOG_TICKS(t);
+	return 0;
+}
+
+/**
+ *	@file: file handle to the watchdog
+ *	@buf: buffer to write (unused as data does not matter here
+ *	@count: count of bytes
+ *	@ppos: pointer to the position to write. No seeks allowed
+ *
+ *	A write to a watchdog device is defined as a keepalive signal.
+ *	
+ *      if 'nowayout' is set then normally a close() is ignored. But
+ *      if you write 'V' first then the close() will stop the timer.
+ */
+
+static ssize_t wdog_write(struct file *file, const char __user *buf,
+						size_t count, loff_t *ppos)
+{
+	if (count) {
+		if (!nowayout) {
+			size_t i;
+
+			/* In case it was set long ago */
+			expect_close = 0;
+
+			for (i = 0; i != count; i++) {
+				char c;
+				if (get_user(c, buf + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 42;
+			}
+		}
+		wdog_ping();
+	}
+	return count;
+}
+
+static int wdog_get_status(void)
+{
+	unsigned long flags;
+	int status = 0;
+	spin_lock_irqsave(&wdog_lock, flags);
+	/* FIXME: readback reset reason */
+	spin_unlock_irqrestore(&wdog_lock, flags);
+	return status;
+}
+
+static uint32_t wdog_get_remaining(void)
+{
+	uint32_t ret = ioread32(__io_address(PM_WDOG));
+	return ret & PM_WDOG_TIME_SET;
+}
+
+/**
+ *	@file: file handle to the device
+ *	@cmd: watchdog command
+ *	@arg: argument pointer
+ *
+ *	The watchdog API defines a common set of functions for all watchdogs
+ *	according to their available features. We only actually usefully support
+ *	querying capabilities and current status.
+ */
+
+static long wdog_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	int new_heartbeat;
+	int status;
+	int options;
+	uint32_t remaining;
+
+	struct watchdog_info ident = {
+		.options =		WDIOF_SETTIMEOUT|
+					WDIOF_MAGICCLOSE|
+					WDIOF_KEEPALIVEPING,
+		.firmware_version =	1,
+		.identity =		"BCM2708",
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+	case WDIOC_GETSTATUS:
+		status = wdog_get_status();
+		return put_user(status, p);
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+	case WDIOC_KEEPALIVE:
+		wdog_ping();
+		return 0;
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_heartbeat, p))
+			return -EFAULT;
+		if (wdog_set_heartbeat(new_heartbeat))
+			return -EINVAL;
+		wdog_ping();
+		/* Fall */
+	case WDIOC_GETTIMEOUT:
+		return put_user(heartbeat, p);
+	case WDIOC_GETTIMELEFT:
+		remaining = WDOG_TICKS_TO_SECS(wdog_get_remaining());
+		return put_user(remaining, p);
+	case WDIOC_SETOPTIONS:
+		if (get_user(options, p))
+			return -EFAULT;
+		if (options & WDIOS_DISABLECARD)
+			wdog_stop();
+		if (options & WDIOS_ENABLECARD)
+			wdog_start(wdog_ticks);
+		return 0;
+	default:
+		return -ENOTTY;
+	}
+}
+
+/**
+ *	@inode: inode of device
+ *	@file: file handle to device
+ *
+ *	The watchdog device has been opened. The watchdog device is single
+ *	open and on opening we load the counters.
+ */
+
+static int wdog_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(0, &wdog_is_open))
+		return -EBUSY;
+	/*
+	 *	Activate
+	 */
+	wdog_start(wdog_ticks);
+	return nonseekable_open(inode, file);
+}
+
+/**
+ *	@inode: inode to board
+ *	@file: file handle to board
+ *
+ *	The watchdog has a configurable API. There is a religious dispute
+ *	between people who want their watchdog to be able to shut down and
+ *	those who want to be sure if the watchdog manager dies the machine
+ *	reboots. In the former case we disable the counters, in the latter
+ *	case you have to open it again very soon.
+ */
+
+static int wdog_release(struct inode *inode, struct file *file)
+{
+	if (expect_close == 42) {
+		wdog_stop();
+	} else {
+		printk(KERN_CRIT
+		 "wdt: WDT device closed unexpectedly.  WDT will not stop!\n");
+		wdog_ping();
+	}
+	clear_bit(0, &wdog_is_open);
+	expect_close = 0;
+	return 0;
+}
+
+/**
+ *	@this: our notifier block
+ *	@code: the event being reported
+ *	@unused: unused
+ *
+ *	Our notifier is called on system shutdowns. Turn the watchdog
+ *	off so that it does not fire during the next reboot.
+ */
+
+static int wdog_notify_sys(struct notifier_block *this, unsigned long code,
+	void *unused)
+{
+	if (code == SYS_DOWN || code == SYS_HALT)
+		wdog_stop();
+	return NOTIFY_DONE;
+}
+
+/*
+ *	Kernel Interfaces
+ */
+
+
+static const struct file_operations wdog_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= wdog_write,
+	.unlocked_ioctl	= wdog_ioctl,
+	.open		= wdog_open,
+	.release	= wdog_release,
+};
+
+static struct miscdevice wdog_miscdev = {
+	.minor	= WATCHDOG_MINOR,
+	.name	= "watchdog",
+	.fops	= &wdog_fops,
+};
+
+/*
+ *	The WDT card needs to learn about soft shutdowns in order to
+ *	turn the timebomb registers off.
+ */
+
+static struct notifier_block wdog_notifier = {
+	.notifier_call = wdog_notify_sys,
+};
+
+/**
+ *	cleanup_module:
+ *
+ *	Unload the watchdog. You cannot do this with any file handles open.
+ *	If your watchdog is set to continue ticking on close and you unload
+ *	it, well it keeps ticking. We won't get the interrupt but the board
+ *	will not touch PC memory so all is fine. You just have to load a new
+ *	module in 60 seconds or reboot.
+ */
+
+static void __exit wdog_exit(void)
+{
+	misc_deregister(&wdog_miscdev);
+	unregister_reboot_notifier(&wdog_notifier);
+}
+
+static int __init wdog_init(void)
+{
+	int ret;
+
+	/* Check that the heartbeat value is within it's range;
+	   if not reset to the default */
+	if (wdog_set_heartbeat(heartbeat)) {
+		wdog_set_heartbeat(WD_TIMO);
+		printk(KERN_INFO "bcm2708_wdog: heartbeat value must be "
+			"0 < heartbeat < %d, using %d\n", 
+				WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
+				WD_TIMO);
+	}
+
+	ret = register_reboot_notifier(&wdog_notifier);
+	if (ret) {
+		printk(KERN_ERR
+		      "wdt: cannot register reboot notifier (err=%d)\n", ret);
+		goto out_reboot;
+	}
+
+	ret = misc_register(&wdog_miscdev);
+	if (ret) {
+		printk(KERN_ERR
+			"wdt: cannot register miscdev on minor=%d (err=%d)\n",
+							WATCHDOG_MINOR, ret);
+		goto out_misc;
+	}
+
+	printk(KERN_INFO "bcm2708 watchdog, heartbeat=%d sec (nowayout=%d)\n",
+		heartbeat, nowayout);
+	return 0;
+
+out_misc:
+	unregister_reboot_notifier(&wdog_notifier);
+out_reboot:
+	return ret;
+}
+
+module_init(wdog_init);
+module_exit(wdog_exit);
+
+MODULE_AUTHOR("Luke Diamand");
+MODULE_DESCRIPTION("Driver for BCM2708 watchdog");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS_MISCDEV(TEMP_MINOR);
+MODULE_LICENSE("GPL");
+
-- 
1.7.5.4

