watchdog: Add TCO support for nVidia chipsets

This driver adds support for /dev/watchdog for boards using either the MCP51 or
MCP55 chipsets.  These are also known as the nForce 430 and nForce 550.  This
driver is likely to work on other chipsets as well, though those are the only
two that have been tested.

Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

1 files changed, 512 insertions, 0 deletions

diff --git a/drivers/watchdog/nv_tco.c b/drivers/watchdog/nv_tco.c
new file mode 100644
index 00000000000..1a50aa7079b
--- /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@kernelconcepts.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@redhat.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);