Date:	Sat, 28 Aug 2010 22:03:45 +0200
From:	Florian Fainelli <florian@...nwrt.org>
To:	Wim Van Sebroeck <wim@...ana.be>, linux-kernel@...r.kernel.org
Subject: [PATCH] WATCHDOG: add support for Broadcom BCM63xx built-in watchdog

This patch adds support for the Broadcom BCM63xx SoC built-in watchdog, it
uses one of the BCM63xx hardware timer id.

Signed-off-by: Miguel Gaio <miguel.gaio@...xo.com>
Signed-off-by: Florian Fainelli <florian@...nwrt.org>
---
The required platform_device code is already present in arch/mips/bcm63xx/
dev-wdt.c.

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index b036677..a3b43d5 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -916,6 +916,16 @@ config OCTEON_WDT
 	  from the first interrupt, it is then only poked when the
 	  device is written.
 
+config BCM63XX_WDT
+	tristate "Broadcom BCM63xx hardware watchdog"
+	depends on BCM63XX
+	help
+	  Watchdog driver for the built in watchdog hardware in Broadcom
+	  BCM63xx SoC.
+
+	  To compile this driver as a loadable module, choose M here.
+	  The module will be called bcm63xx_wdt.
+
 # PARISC Architecture
 
 # POWERPC Architecture
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 8374503..4b0ef38 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -109,6 +109,7 @@ obj-$(CONFIG_SBC_EPX_C3_WATCHDOG) += sbc_epx_c3.o
 
 # MIPS Architecture
 obj-$(CONFIG_BCM47XX_WDT) += bcm47xx_wdt.o
+obj-$(CONFIG_BCM63XX_WDT) += bcm63xx_wdt.o
 obj-$(CONFIG_RC32434_WDT) += rc32434_wdt.o
 obj-$(CONFIG_INDYDOG) += indydog.o
 obj-$(CONFIG_WDT_MTX1) += mtx-1_wdt.o
diff --git a/drivers/watchdog/bcm63xx_wdt.c b/drivers/watchdog/bcm63xx_wdt.c
new file mode 100644
index 0000000..a1debc8
--- /dev/null
+++ b/drivers/watchdog/bcm63xx_wdt.c
@@ -0,0 +1,350 @@
+/*
+ *  Broadcom BCM63xx SoC watchdog driver
+ *
+ *  Copyright (C) 2007, Miguel Gaio <miguel.gaio@...xo.com>
+ *  Copyright (C) 2008, Florian Fainelli <florian@...nwrt.org>
+ *
+ *  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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/reboot.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/watchdog.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <linux/interrupt.h>
+#include <linux/ptrace.h>
+#include <linux/resource.h>
+#include <linux/platform_device.h>
+
+#include <bcm63xx_cpu.h>
+#include <bcm63xx_io.h>
+#include <bcm63xx_regs.h>
+#include <bcm63xx_timer.h>
+
+#define PFX KBUILD_MODNAME
+
+#define WDT_HZ		50000000 /* Fclk */
+#define WDT_DEFAULT_TIME	30      /* seconds */
+#define WDT_MAX_TIME		256     /* seconds */
+
+static struct {
+	void __iomem *regs;
+	struct timer_list timer;
+	int default_ticks;
+	unsigned long inuse;
+	atomic_t ticks;
+} bcm63xx_wdt_device;
+
+static int expect_close;
+
+static int wdt_time = WDT_DEFAULT_TIME;
+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) ")");
+
+/* HW functions */
+static void bcm63xx_wdt_hw_start(void)
+{
+	bcm_writel(0xfffffffe, bcm63xx_wdt_device.regs + WDT_DEFVAL_REG);
+	bcm_writel(WDT_START_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
+	bcm_writel(WDT_START_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
+}
+
+static void bcm63xx_wdt_hw_stop(void)
+{
+	bcm_writel(WDT_STOP_1, bcm63xx_wdt_device.regs + WDT_CTL_REG);
+	bcm_writel(WDT_STOP_2, bcm63xx_wdt_device.regs + WDT_CTL_REG);
+}
+
+static void bcm63xx_wdt_isr(void *data)
+{
+	struct pt_regs *regs = get_irq_regs();
+
+	die(PFX " fire", regs);
+}
+
+static void bcm63xx_timer_tick(unsigned long unused)
+{
+	if (!atomic_dec_and_test(&bcm63xx_wdt_device.ticks)) {
+		bcm63xx_wdt_hw_start();
+		mod_timer(&bcm63xx_wdt_device.timer, jiffies + HZ);
+	} else
+		printk(KERN_CRIT PFX ": watchdog will restart system\n");
+}
+
+static void bcm63xx_wdt_pet(void)
+{
+	atomic_set(&bcm63xx_wdt_device.ticks, wdt_time);
+}
+
+static void bcm63xx_wdt_start(void)
+{
+	bcm63xx_wdt_pet();
+	bcm63xx_timer_tick(0);
+}
+
+static void bcm63xx_wdt_pause(void)
+{
+	del_timer_sync(&bcm63xx_wdt_device.timer);
+	bcm63xx_wdt_hw_stop();
+}
+
+static int bcm63xx_wdt_settimeout(int new_time)
+{
+	if ((new_time <= 0) || (new_time > WDT_MAX_TIME))
+		return -EINVAL;
+
+	wdt_time = new_time;
+
+	return 0;
+}
+
+static int bcm63xx_wdt_open(struct inode *inode, struct file *file)
+{
+	if (test_and_set_bit(0, &bcm63xx_wdt_device.inuse))
+		return -EBUSY;
+
+	bcm63xx_wdt_start();
+	return nonseekable_open(inode, file);
+}
+
+static int bcm63xx_wdt_release(struct inode *inode, struct file *file)
+{
+	if (expect_close == 42)
+		bcm63xx_wdt_pause();
+	else {
+		printk(KERN_CRIT PFX
+			": Unexpected close, not stopping watchdog!\n");
+		bcm63xx_wdt_start();
+	}
+	clear_bit(0, &bcm63xx_wdt_device.inuse);
+	expect_close = 0;
+	return 0;
+}
+
+static ssize_t bcm63xx_wdt_write(struct file *file, const char *data,
+				size_t len, loff_t *ppos)
+{
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			/* In case it was set long ago */
+			expect_close = 0;
+
+			for (i = 0; i != len; i++) {
+				char c;
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					expect_close = 42;
+			}
+		}
+		bcm63xx_wdt_pet();
+	}
+	return len;
+}
+
+static struct watchdog_info bcm63xx_wdt_info = {
+	.identity       = PFX,
+	.options        = WDIOF_SETTIMEOUT |
+				WDIOF_KEEPALIVEPING |
+				WDIOF_MAGICCLOSE,
+};
+
+
+static long bcm63xx_wdt_ioctl(struct file *file, unsigned int cmd,
+				unsigned long arg)
+{
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	int new_value, retval = -EINVAL;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user(argp, &bcm63xx_wdt_info,
+			sizeof(bcm63xx_wdt_info)) ? -EFAULT : 0;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+
+	case WDIOC_SETOPTIONS:
+		if (get_user(new_value, p))
+			return -EFAULT;
+
+		if (new_value & WDIOS_DISABLECARD) {
+			bcm63xx_wdt_pause();
+			retval = 0;
+		}
+		if (new_value & WDIOS_ENABLECARD) {
+			bcm63xx_wdt_start();
+			retval = 0;
+		}
+
+		return retval;
+
+	case WDIOC_KEEPALIVE:
+		bcm63xx_wdt_pet();
+		return 0;
+
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_value, p))
+			return -EFAULT;
+
+		if (bcm63xx_wdt_settimeout(new_value))
+			return -EINVAL;
+
+		bcm63xx_wdt_pet();
+
+	case WDIOC_GETTIMEOUT:
+		return put_user(wdt_time, p);
+
+	default:
+		return -ENOTTY;
+
+	}
+}
+
+static int bcm63xx_wdt_notify_sys(struct notifier_block *this,
+				unsigned long code, void *unused)
+{
+	if (code == SYS_DOWN || code == SYS_HALT)
+		bcm63xx_wdt_pause();
+	return NOTIFY_DONE;
+}
+
+static const struct file_operations bcm63xx_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= bcm63xx_wdt_write,
+	.unlocked_ioctl	= bcm63xx_wdt_ioctl,
+	.open		= bcm63xx_wdt_open,
+	.release	= bcm63xx_wdt_release,
+};
+
+static struct miscdevice bcm63xx_wdt_miscdev = {
+	.minor	= WATCHDOG_MINOR,
+	.name	= "watchdog",
+	.fops	= &bcm63xx_wdt_fops,
+};
+
+static struct notifier_block bcm63xx_wdt_notifier = {
+	.notifier_call = bcm63xx_wdt_notify_sys,
+};
+
+
+static int bcm63xx_wdt_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct resource *r;
+
+	setup_timer(&bcm63xx_wdt_device.timer, bcm63xx_timer_tick, 0L);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r) {
+		dev_err(&pdev->dev, "failed to get resources\n");
+		return -ENODEV;
+	}
+
+	bcm63xx_wdt_device.regs = ioremap_nocache(r->start, r->end - r->start);
+	if (!bcm63xx_wdt_device.regs) {
+		dev_err(&pdev->dev, "failed to remap I/O resources\n");
+		return -ENXIO;
+	}
+
+	ret = bcm63xx_timer_register(TIMER_WDT_ID, bcm63xx_wdt_isr, NULL);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to register wdt timer isr\n");
+		goto unmap;
+	}
+
+	if (bcm63xx_wdt_settimeout(wdt_time)) {
+		bcm63xx_wdt_settimeout(WDT_DEFAULT_TIME);
+		dev_info(&pdev->dev,
+			": wdt_time value must be 1 <= wdt_time <= 256, using %d\n",
+			wdt_time);
+	}
+
+	ret = register_reboot_notifier(&bcm63xx_wdt_notifier);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to register reboot_notifier\n");
+		goto unregister_timer;
+	}
+
+	ret = misc_register(&bcm63xx_wdt_miscdev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to register watchdog device\n");
+		goto unregister_reboot_notifier;
+	}
+
+	dev_info(&pdev->dev, " started, timer margin: %d sec\n",
+						WDT_DEFAULT_TIME);
+
+	return 0;
+
+unregister_reboot_notifier:
+	unregister_reboot_notifier(&bcm63xx_wdt_notifier);
+unregister_timer:
+	bcm63xx_timer_unregister(TIMER_WDT_ID);
+unmap:
+	iounmap(bcm63xx_wdt_device.regs);
+	return ret;
+}
+
+static int bcm63xx_wdt_remove(struct platform_device *pdev)
+{
+	if (!nowayout)
+		bcm63xx_wdt_pause();
+
+	misc_deregister(&bcm63xx_wdt_miscdev);
+
+	iounmap(bcm63xx_wdt_device.regs);
+
+	unregister_reboot_notifier(&bcm63xx_wdt_notifier);
+	bcm63xx_timer_unregister(TIMER_WDT_ID);
+
+	return 0;
+}
+
+static struct platform_driver bcm63xx_wdt = {
+	.probe	= bcm63xx_wdt_probe,
+	.remove = bcm63xx_wdt_remove,
+	.driver = {
+		.name = "bcm63xx-wdt",
+	}
+};
+
+static int __init bcm63xx_wdt_init(void)
+{
+	return platform_driver_register(&bcm63xx_wdt);
+}
+
+static void __exit bcm63xx_wdt_exit(void)
+{
+	platform_driver_unregister(&bcm63xx_wdt);
+}
+
+module_init(bcm63xx_wdt_init);
+module_exit(bcm63xx_wdt_exit);
+
+MODULE_AUTHOR("Miguel Gaio <miguel.gaio@...xo.com>");
+MODULE_AUTHOR("Florian Fainelli <florian@...nwrt.org>");
+MODULE_DESCRIPTION("Driver for the Broadcom BCM63xx SoC watchdog");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS("platform:bcm63xx-wdt");
--
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