Date:	Fri, 7 Jan 2011 09:26:03 +0100
From:	Wim Van Sebroeck <wim@...ana.be>
To:	Mike Waychison <mikew@...gle.com>
Cc:	linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] watchdog: Add TCO support for nVidia chipsets

Hi Mike,

this is the adapted code for the nvidia watchdog.

Thanks in advance,
Wim.
------------------------------------------------------
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index abb9bd8..de99bf9 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -642,6 +642,24 @@ config PC87413_WDT
 
 	  Most people will say N.
 
+config NV_TCO
+	tristate "nVidia TCO Timer/Watchdog"
+	depends on X86 && PCI
+	---help---
+	  Hardware driver for the TCO timer built into the nVidia Hub family
+	  (such as the MCP51).  The TCO (Total Cost of Ownership) timer is a
+	  watchdog timer that will reboot the machine after its second
+	  expiration. The expiration time can be configured with the
+	  "heartbeat" parameter.
+
+	  On some motherboards the driver may fail to reset the chipset's
+	  NO_REBOOT flag which prevents the watchdog from rebooting the
+	  machine. If this is the case you will get a kernel message like
+	  "failed to reset NO_REBOOT flag, reboot disabled by hardware".
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called nv_tco.
+
 config RDC321X_WDT
 	tristate "RDC R-321x SoC watchdog"
 	depends on X86_RDC321X
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 12e6c1e..cd77f54 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -87,6 +87,7 @@ obj-$(CONFIG_HP_WATCHDOG) += hpwdt.o
 obj-$(CONFIG_SC1200_WDT) += sc1200wdt.o
 obj-$(CONFIG_SCx200_WDT) += scx200_wdt.o
 obj-$(CONFIG_PC87413_WDT) += pc87413_wdt.o
+obj-$(CONFIG_NV_TCO) += nv_tco.o
 obj-$(CONFIG_RDC321X_WDT) += rdc321x_wdt.o
 obj-$(CONFIG_60XX_WDT) += sbc60xxwdt.o
 obj-$(CONFIG_SBC8360_WDT) += sbc8360.o
diff --git a/drivers/watchdog/nv_tco.c b/drivers/watchdog/nv_tco.c
new file mode 100644
index 0000000..c5b8ce4
--- /dev/null
+++ b/drivers/watchdog/nv_tco.c
@@ -0,0 +1,512 @@
+/*
+ *	nv_tco 0.01:	TCO timer driver for NV chipsets
+ *
+ *	(c) Copyright 2005 Google Inc., All Rights Reserved.
+ *
+ *	Based off i8xx_tco.c:
+ *	(c) Copyright 2000 kernel concepts <nils@...nelconcepts.de>, All Rights
+ *	Reserved.
+ *				http://www.kernelconcepts.de
+ *
+ *	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.
+ *
+ *	TCO timer driver for NV chipsets
+ *	based on softdog.c by Alan Cox <alan@...hat.com>
+ */
+
+/*
+ *	Includes, defines, variables, module parameters, ...
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/pci.h>
+#include <linux/ioport.h>
+#include <linux/jiffies.h>
+#include <linux/platform_device.h>
+#include <linux/uaccess.h>
+#include <linux/io.h>
+
+#include "nv_tco.h"
+
+/* Module and version information */
+#define TCO_VERSION "0.01"
+#define TCO_MODULE_NAME "NV_TCO"
+#define TCO_DRIVER_NAME   TCO_MODULE_NAME ", v" TCO_VERSION
+#define PFX TCO_MODULE_NAME ": "
+
+/* internal variables */
+static unsigned int tcobase;
+static DEFINE_SPINLOCK(tco_lock);	/* Guards the hardware */
+static unsigned long timer_alive;
+static char tco_expect_close;
+static struct pci_dev *tco_pci;
+
+/* the watchdog platform device */
+static struct platform_device *nv_tco_platform_device;
+
+/* module parameters */
+#define WATCHDOG_HEARTBEAT 30	/* 30 sec default heartbeat (2<heartbeat<39) */
+static int heartbeat = WATCHDOG_HEARTBEAT;  /* in seconds */
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, "
+			    "default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
+
+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) ")");
+
+/*
+ * Some TCO specific functions
+ */
+static inline unsigned char seconds_to_ticks(int seconds)
+{
+	/* the internal timer is stored as ticks which decrement
+	 * every 0.6 seconds */
+	return (seconds * 10) / 6;
+}
+
+static void tco_timer_start(void)
+{
+	u32 val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tco_lock, flags);
+	val = inl(TCO_CNT(tcobase));
+	val &= ~TCO_CNT_TCOHALT;
+	outl(val, TCO_CNT(tcobase));
+	spin_unlock_irqrestore(&tco_lock, flags);
+}
+
+static void tco_timer_stop(void)
+{
+	u32 val;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tco_lock, flags);
+	val = inl(TCO_CNT(tcobase));
+	val |= TCO_CNT_TCOHALT;
+	outl(val, TCO_CNT(tcobase));
+	spin_unlock_irqrestore(&tco_lock, flags);
+}
+
+static void tco_timer_keepalive(void)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&tco_lock, flags);
+	outb(0x01, TCO_RLD(tcobase));
+	spin_unlock_irqrestore(&tco_lock, flags);
+}
+
+static int tco_timer_set_heartbeat(int t)
+{
+	int ret = 0;
+	unsigned char tmrval;
+	unsigned long flags;
+	u8 val;
+
+	/*
+	 * note seconds_to_ticks(t) > t, so if t > 0x3f, so is
+	 * tmrval=seconds_to_ticks(t).  Check that the count in seconds isn't
+	 * out of range on it's own (to avoid overflow in tmrval).
+	 */
+	if (t < 0 || t > 0x3f)
+		return -EINVAL;
+	tmrval = seconds_to_ticks(t);
+
+	/* "Values of 0h-3h are ignored and should not be attempted" */
+	if (tmrval > 0x3f || tmrval < 0x04)
+		return -EINVAL;
+
+	/* Write new heartbeat to watchdog */
+	spin_lock_irqsave(&tco_lock, flags);
+	val = inb(TCO_TMR(tcobase));
+	val &= 0xc0;
+	val |= tmrval;
+	outb(val, TCO_TMR(tcobase));
+	val = inb(TCO_TMR(tcobase));
+
+	if ((val & 0x3f) != tmrval)
+		ret = -EINVAL;
+	spin_unlock_irqrestore(&tco_lock, flags);
+
+	if (ret)
+		return ret;
+
+	heartbeat = t;
+	return 0;
+}
+
+/*
+ *	/dev/watchdog handling
+ */
+
+static int nv_tco_open(struct inode *inode, struct file *file)
+{
+	/* /dev/watchdog can only be opened once */
+	if (test_and_set_bit(0, &timer_alive))
+		return -EBUSY;
+
+	/* Reload and activate timer */
+	tco_timer_keepalive();
+	tco_timer_start();
+	return nonseekable_open(inode, file);
+}
+
+static int nv_tco_release(struct inode *inode, struct file *file)
+{
+	/* Shut off the timer */
+	if (tco_expect_close == 42) {
+		tco_timer_stop();
+	} else {
+		printk(KERN_CRIT PFX "Unexpected close, not stopping "
+		       "watchdog!\n");
+		tco_timer_keepalive();
+	}
+	clear_bit(0, &timer_alive);
+	tco_expect_close = 0;
+	return 0;
+}
+
+static ssize_t nv_tco_write(struct file *file, const char __user *data,
+			    size_t len, loff_t *ppos)
+{
+	/* See if we got the magic character 'V' and reload the timer */
+	if (len) {
+		if (!nowayout) {
+			size_t i;
+
+			/*
+			 * note: just in case someone wrote the magic character
+			 * five months ago...
+			 */
+			tco_expect_close = 0;
+
+			/*
+			 * scan to see whether or not we got the magic
+			 * character
+			 */
+			for (i = 0; i != len; i++) {
+				char c;
+				if (get_user(c, data + i))
+					return -EFAULT;
+				if (c == 'V')
+					tco_expect_close = 42;
+			}
+		}
+
+		/* someone wrote to us, we should reload the timer */
+		tco_timer_keepalive();
+	}
+	return len;
+}
+
+static long nv_tco_ioctl(struct file *file, unsigned int cmd,
+			 unsigned long arg)
+{
+	int new_options, retval = -EINVAL;
+	int new_heartbeat;
+	void __user *argp = (void __user *)arg;
+	int __user *p = argp;
+	static const struct watchdog_info ident = {
+		.options =		WDIOF_SETTIMEOUT |
+					WDIOF_KEEPALIVEPING |
+					WDIOF_MAGICCLOSE,
+		.firmware_version =	0,
+		.identity =		TCO_MODULE_NAME,
+	};
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		return put_user(0, p);
+	case WDIOC_SETOPTIONS:
+		if (get_user(new_options, p))
+			return -EFAULT;
+		if (new_options & WDIOS_DISABLECARD) {
+			tco_timer_stop();
+			retval = 0;
+		}
+		if (new_options & WDIOS_ENABLECARD) {
+			tco_timer_keepalive();
+			tco_timer_start();
+			retval = 0;
+		}
+		return retval;
+	case WDIOC_KEEPALIVE:
+		tco_timer_keepalive();
+		return 0;
+	case WDIOC_SETTIMEOUT:
+		if (get_user(new_heartbeat, p))
+			return -EFAULT;
+		if (tco_timer_set_heartbeat(new_heartbeat))
+			return -EINVAL;
+		tco_timer_keepalive();
+		/* Fall through */
+	case WDIOC_GETTIMEOUT:
+		return put_user(heartbeat, p);
+	default:
+		return -ENOTTY;
+	}
+}
+
+/*
+ *	Kernel Interfaces
+ */
+
+static const struct file_operations nv_tco_fops = {
+	.owner =		THIS_MODULE,
+	.llseek =		no_llseek,
+	.write =		nv_tco_write,
+	.unlocked_ioctl =	nv_tco_ioctl,
+	.open =			nv_tco_open,
+	.release =		nv_tco_release,
+};
+
+static struct miscdevice nv_tco_miscdev = {
+	.minor =	WATCHDOG_MINOR,
+	.name =		"watchdog",
+	.fops =		&nv_tco_fops,
+};
+
+/*
+ * Data for PCI driver interface
+ *
+ * This data only exists for exporting the supported
+ * PCI ids via MODULE_DEVICE_TABLE.  We do not actually
+ * register a pci_driver, because someone else might one day
+ * want to register another driver on the same PCI id.
+ */
+static struct pci_device_id tco_pci_tbl[] = {
+	{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS,
+	  PCI_ANY_ID, PCI_ANY_ID, },
+	{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS,
+	  PCI_ANY_ID, PCI_ANY_ID, },
+	{ 0, },			/* End of list */
+};
+MODULE_DEVICE_TABLE(pci, tco_pci_tbl);
+
+/*
+ *	Init & exit routines
+ */
+
+static unsigned char __init nv_tco_getdevice(void)
+{
+	struct pci_dev *dev = NULL;
+	u32 val;
+
+	/* Find the PCI device */
+	for_each_pci_dev(dev) {
+		if (pci_match_id(tco_pci_tbl, dev) != NULL) {
+			tco_pci = dev;
+			break;
+		}
+	}
+
+	if (!tco_pci)
+		return 0;
+
+	/* Find the base io port */
+	pci_read_config_dword(tco_pci, 0x64, &val);
+	val &= 0xffff;
+	if (val == 0x0001 || val == 0x0000) {
+		/* Something is wrong here, bar isn't setup */
+		printk(KERN_ERR PFX "failed to get tcobase address\n");
+		return 0;
+	}
+	val &= 0xff00;
+	tcobase = val + 0x40;
+
+	if (!request_region(tcobase, 0x10, "NV TCO")) {
+		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
+		       tcobase);
+		return 0;
+	}
+
+	/* Set a reasonable heartbeat before we stop the timer */
+	tco_timer_set_heartbeat(30);
+
+	/*
+	 * Stop the TCO before we change anything so we don't race with
+	 * a zeroed timer.
+	 */
+	tco_timer_keepalive();
+	tco_timer_stop();
+
+	/* Disable SMI caused by TCO */
+	if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) {
+		printk(KERN_ERR PFX "I/O address 0x%04x already in use\n",
+		       MCP51_SMI_EN(tcobase));
+		goto out;
+	}
+	val = inl(MCP51_SMI_EN(tcobase));
+	val &= ~MCP51_SMI_EN_TCO;
+	outl(val, MCP51_SMI_EN(tcobase));
+	val = inl(MCP51_SMI_EN(tcobase));
+	release_region(MCP51_SMI_EN(tcobase), 4);
+	if (val & MCP51_SMI_EN_TCO) {
+		printk(KERN_ERR PFX "Could not disable SMI caused by TCO\n");
+		goto out;
+	}
+
+	/* Check chipset's NO_REBOOT bit */
+	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
+	val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT;
+	pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
+	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
+	if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) {
+		printk(KERN_ERR PFX "failed to reset NO_REBOOT flag, reboot "
+		       "disabled by hardware\n");
+		goto out;
+	}
+
+	return 1;
+out:
+	release_region(tcobase, 0x10);
+	return 0;
+}
+
+static int __devinit nv_tco_init(struct platform_device *dev)
+{
+	int ret;
+
+	/* Check whether or not the hardware watchdog is there */
+	if (!nv_tco_getdevice())
+		return -ENODEV;
+
+	/* Check to see if last reboot was due to watchdog timeout */
+	printk(KERN_INFO PFX "Watchdog reboot %sdetected.\n",
+	       inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not ");
+
+	/* Clear out the old status */
+	outl(TCO_STS_RESET, TCO_STS(tcobase));
+
+	/*
+	 * Check that the heartbeat value is within it's range.
+	 * If not, reset to the default.
+	 */
+	if (tco_timer_set_heartbeat(heartbeat)) {
+		heartbeat = WATCHDOG_HEARTBEAT;
+		tco_timer_set_heartbeat(heartbeat);
+		printk(KERN_INFO PFX "heartbeat value must be 2<heartbeat<39, "
+		       "using %d\n", heartbeat);
+	}
+
+	ret = misc_register(&nv_tco_miscdev);
+	if (ret != 0) {
+		printk(KERN_ERR PFX "cannot register miscdev on minor=%d "
+		       "(err=%d)\n", WATCHDOG_MINOR, ret);
+		goto unreg_region;
+	}
+
+	clear_bit(0, &timer_alive);
+
+	tco_timer_stop();
+
+	printk(KERN_INFO PFX "initialized (0x%04x). heartbeat=%d sec "
+	       "(nowayout=%d)\n", tcobase, heartbeat, nowayout);
+
+	return 0;
+
+unreg_region:
+	release_region(tcobase, 0x10);
+	return ret;
+}
+
+static void __devexit nv_tco_cleanup(void)
+{
+	u32 val;
+
+	/* Stop the timer before we leave */
+	if (!nowayout)
+		tco_timer_stop();
+
+	/* Set the NO_REBOOT bit to prevent later reboots, just for sure */
+	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
+	val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT;
+	pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val);
+	pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val);
+	if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) {
+		printk(KERN_CRIT PFX "Couldn't unset REBOOT bit.  Machine may "
+		       "soon reset\n");
+	}
+
+	/* Deregister */
+	misc_deregister(&nv_tco_miscdev);
+	release_region(tcobase, 0x10);
+}
+
+static int __devexit nv_tco_remove(struct platform_device *dev)
+{
+	if (tcobase)
+		nv_tco_cleanup();
+
+	return 0;
+}
+
+static void nv_tco_shutdown(struct platform_device *dev)
+{
+	tco_timer_stop();
+}
+
+static struct platform_driver nv_tco_driver = {
+	.probe		= nv_tco_init,
+	.remove		= __devexit_p(nv_tco_remove),
+	.shutdown	= nv_tco_shutdown,
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= TCO_MODULE_NAME,
+	},
+};
+
+static int __init nv_tco_init_module(void)
+{
+	int err;
+
+	printk(KERN_INFO PFX "NV TCO WatchDog Timer Driver v%s\n",
+	       TCO_VERSION);
+
+	err = platform_driver_register(&nv_tco_driver);
+	if (err)
+		return err;
+
+	nv_tco_platform_device = platform_device_register_simple(
+					TCO_MODULE_NAME, -1, NULL, 0);
+	if (IS_ERR(nv_tco_platform_device)) {
+		err = PTR_ERR(nv_tco_platform_device);
+		goto unreg_platform_driver;
+	}
+
+	return 0;
+
+unreg_platform_driver:
+	platform_driver_unregister(&nv_tco_driver);
+	return err;
+}
+
+static void __exit nv_tco_cleanup_module(void)
+{
+	platform_device_unregister(nv_tco_platform_device);
+	platform_driver_unregister(&nv_tco_driver);
+	printk(KERN_INFO PFX "NV TCO Watchdog Module Unloaded.\n");
+}
+
+module_init(nv_tco_init_module);
+module_exit(nv_tco_cleanup_module);
+
+MODULE_AUTHOR("Mike Waychison");
+MODULE_DESCRIPTION("TCO timer driver for NV chipsets");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
diff --git a/drivers/watchdog/nv_tco.h b/drivers/watchdog/nv_tco.h
new file mode 100644
index 0000000..c2d1d04
--- /dev/null
+++ b/drivers/watchdog/nv_tco.h
@@ -0,0 +1,64 @@
+/*
+ *	nv_tco:	TCO timer driver for nVidia chipsets.
+ *
+ *	(c) Copyright 2005 Google Inc., All Rights Reserved.
+ *
+ *	Supported Chipsets:
+ *		- MCP51/MCP55
+ *
+ *	(c) Copyright 2000 kernel concepts <nils@...nelconcepts.de>, All Rights
+ *	Reserved.
+ *				http://www.kernelconcepts.de
+ *
+ *	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.
+ *
+ *	Neither kernel concepts nor Nils Faerber admit liability nor provide
+ *	warranty for any of this software. This material is provided
+ *	"AS-IS" and at no charge.
+ *
+ *	(c) Copyright 2000	kernel concepts <nils@...nelconcepts.de>
+ *				developed for
+ *                              Jentro AG, Haar/Munich (Germany)
+ *
+ *	TCO timer driver for NV chipsets
+ *	based on softdog.c by Alan Cox <alan@...hat.com>
+ */
+
+/*
+ * Some address definitions for the TCO
+ */
+
+#define TCO_RLD(base)	((base) + 0x00)	/* TCO Timer Reload and Current Value */
+#define TCO_TMR(base)	((base) + 0x01)	/* TCO Timer Initial Value	*/
+
+#define TCO_STS(base)	((base) + 0x04)	/* TCO Status Register		*/
+/*
+ * TCO Boot Status bit: set on TCO reset, reset by software or standby
+ * power-good (survives reboots), unfortunately this bit is never
+ * set.
+ */
+#  define TCO_STS_BOOT_STS	(1 << 9)
+/*
+ * first and 2nd timeout status bits, these also survive a warm boot,
+ * and they work, so we use them.
+ */
+#  define TCO_STS_TCO_INT_STS	(1 << 1)
+#  define TCO_STS_TCO2TO_STS	(1 << 10)
+#  define TCO_STS_RESET		(TCO_STS_BOOT_STS | TCO_STS_TCO2TO_STS | \
+				 TCO_STS_TCO_INT_STS)
+
+#define TCO_CNT(base)	((base) + 0x08)	/* TCO Control Register	*/
+#  define TCO_CNT_TCOHALT	(1 << 12)
+
+#define MCP51_SMBUS_SETUP_B 0xe8
+#  define MCP51_SMBUS_SETUP_B_TCO_REBOOT (1 << 25)
+
+/*
+ * The SMI_EN register is at the base io address + 0x04,
+ * while TCOBASE is + 0x40.
+ */
+#define MCP51_SMI_EN(base)	((base) - 0x40 + 0x04)
+#  define MCP51_SMI_EN_TCO	((1 << 4) | (1 << 5))
--
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