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515 lines
12 KiB
515 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* nv_tco 0.01: TCO timer driver for NV chipsets |
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* |
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* (c) Copyright 2005 Google Inc., All Rights Reserved. |
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* |
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* Based off i8xx_tco.c: |
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* (c) Copyright 2000 kernel concepts <[email protected]>, All Rights |
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* Reserved. |
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* https://www.kernelconcepts.de |
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* |
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* TCO timer driver for NV chipsets |
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* based on softdog.c by Alan Cox <[email protected]> |
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*/ |
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/* |
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* Includes, defines, variables, module parameters, ... |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/types.h> |
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#include <linux/miscdevice.h> |
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#include <linux/watchdog.h> |
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#include <linux/init.h> |
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#include <linux/fs.h> |
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#include <linux/pci.h> |
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#include <linux/ioport.h> |
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#include <linux/jiffies.h> |
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#include <linux/platform_device.h> |
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#include <linux/uaccess.h> |
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#include <linux/io.h> |
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#include "nv_tco.h" |
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/* Module and version information */ |
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#define TCO_VERSION "0.01" |
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#define TCO_MODULE_NAME "NV_TCO" |
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#define TCO_DRIVER_NAME TCO_MODULE_NAME ", v" TCO_VERSION |
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/* internal variables */ |
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static unsigned int tcobase; |
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static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */ |
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static unsigned long timer_alive; |
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static char tco_expect_close; |
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static struct pci_dev *tco_pci; |
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/* the watchdog platform device */ |
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static struct platform_device *nv_tco_platform_device; |
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/* module parameters */ |
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#define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat (2<heartbeat<39) */ |
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static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */ |
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module_param(heartbeat, int, 0); |
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MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (2<heartbeat<39, " |
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"default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")"); |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started" |
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" (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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/* |
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* Some TCO specific functions |
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*/ |
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static inline unsigned char seconds_to_ticks(int seconds) |
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{ |
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/* the internal timer is stored as ticks which decrement |
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* every 0.6 seconds */ |
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return (seconds * 10) / 6; |
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} |
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static void tco_timer_start(void) |
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{ |
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u32 val; |
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unsigned long flags; |
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spin_lock_irqsave(&tco_lock, flags); |
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val = inl(TCO_CNT(tcobase)); |
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val &= ~TCO_CNT_TCOHALT; |
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outl(val, TCO_CNT(tcobase)); |
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spin_unlock_irqrestore(&tco_lock, flags); |
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} |
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static void tco_timer_stop(void) |
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{ |
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u32 val; |
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unsigned long flags; |
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spin_lock_irqsave(&tco_lock, flags); |
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val = inl(TCO_CNT(tcobase)); |
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val |= TCO_CNT_TCOHALT; |
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outl(val, TCO_CNT(tcobase)); |
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spin_unlock_irqrestore(&tco_lock, flags); |
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} |
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static void tco_timer_keepalive(void) |
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{ |
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unsigned long flags; |
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spin_lock_irqsave(&tco_lock, flags); |
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outb(0x01, TCO_RLD(tcobase)); |
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spin_unlock_irqrestore(&tco_lock, flags); |
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} |
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static int tco_timer_set_heartbeat(int t) |
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{ |
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int ret = 0; |
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unsigned char tmrval; |
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unsigned long flags; |
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u8 val; |
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/* |
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* note seconds_to_ticks(t) > t, so if t > 0x3f, so is |
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* tmrval=seconds_to_ticks(t). Check that the count in seconds isn't |
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* out of range on it's own (to avoid overflow in tmrval). |
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*/ |
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if (t < 0 || t > 0x3f) |
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return -EINVAL; |
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tmrval = seconds_to_ticks(t); |
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/* "Values of 0h-3h are ignored and should not be attempted" */ |
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if (tmrval > 0x3f || tmrval < 0x04) |
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return -EINVAL; |
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/* Write new heartbeat to watchdog */ |
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spin_lock_irqsave(&tco_lock, flags); |
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val = inb(TCO_TMR(tcobase)); |
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val &= 0xc0; |
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val |= tmrval; |
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outb(val, TCO_TMR(tcobase)); |
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val = inb(TCO_TMR(tcobase)); |
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if ((val & 0x3f) != tmrval) |
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ret = -EINVAL; |
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spin_unlock_irqrestore(&tco_lock, flags); |
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if (ret) |
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return ret; |
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heartbeat = t; |
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return 0; |
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} |
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/* |
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* /dev/watchdog handling |
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*/ |
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static int nv_tco_open(struct inode *inode, struct file *file) |
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{ |
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/* /dev/watchdog can only be opened once */ |
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if (test_and_set_bit(0, &timer_alive)) |
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return -EBUSY; |
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/* Reload and activate timer */ |
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tco_timer_keepalive(); |
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tco_timer_start(); |
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return stream_open(inode, file); |
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} |
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static int nv_tco_release(struct inode *inode, struct file *file) |
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{ |
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/* Shut off the timer */ |
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if (tco_expect_close == 42) { |
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tco_timer_stop(); |
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} else { |
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pr_crit("Unexpected close, not stopping watchdog!\n"); |
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tco_timer_keepalive(); |
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} |
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clear_bit(0, &timer_alive); |
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tco_expect_close = 0; |
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return 0; |
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} |
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static ssize_t nv_tco_write(struct file *file, const char __user *data, |
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size_t len, loff_t *ppos) |
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{ |
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/* See if we got the magic character 'V' and reload the timer */ |
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if (len) { |
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if (!nowayout) { |
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size_t i; |
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/* |
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* note: just in case someone wrote the magic character |
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* five months ago... |
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*/ |
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tco_expect_close = 0; |
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/* |
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* scan to see whether or not we got the magic |
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* character |
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*/ |
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for (i = 0; i != len; i++) { |
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char c; |
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if (get_user(c, data + i)) |
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return -EFAULT; |
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if (c == 'V') |
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tco_expect_close = 42; |
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} |
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} |
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/* someone wrote to us, we should reload the timer */ |
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tco_timer_keepalive(); |
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} |
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return len; |
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} |
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static long nv_tco_ioctl(struct file *file, unsigned int cmd, |
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unsigned long arg) |
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{ |
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int new_options, retval = -EINVAL; |
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int new_heartbeat; |
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void __user *argp = (void __user *)arg; |
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int __user *p = argp; |
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static const struct watchdog_info ident = { |
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.options = WDIOF_SETTIMEOUT | |
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WDIOF_KEEPALIVEPING | |
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WDIOF_MAGICCLOSE, |
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.firmware_version = 0, |
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.identity = TCO_MODULE_NAME, |
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}; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; |
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case WDIOC_GETSTATUS: |
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case WDIOC_GETBOOTSTATUS: |
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return put_user(0, p); |
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case WDIOC_SETOPTIONS: |
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if (get_user(new_options, p)) |
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return -EFAULT; |
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if (new_options & WDIOS_DISABLECARD) { |
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tco_timer_stop(); |
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retval = 0; |
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} |
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if (new_options & WDIOS_ENABLECARD) { |
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tco_timer_keepalive(); |
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tco_timer_start(); |
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retval = 0; |
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} |
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return retval; |
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case WDIOC_KEEPALIVE: |
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tco_timer_keepalive(); |
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return 0; |
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case WDIOC_SETTIMEOUT: |
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if (get_user(new_heartbeat, p)) |
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return -EFAULT; |
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if (tco_timer_set_heartbeat(new_heartbeat)) |
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return -EINVAL; |
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tco_timer_keepalive(); |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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return put_user(heartbeat, p); |
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default: |
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return -ENOTTY; |
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} |
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} |
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/* |
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* Kernel Interfaces |
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*/ |
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static const struct file_operations nv_tco_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = nv_tco_write, |
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.unlocked_ioctl = nv_tco_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = nv_tco_open, |
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.release = nv_tco_release, |
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}; |
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static struct miscdevice nv_tco_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &nv_tco_fops, |
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}; |
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/* |
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* Data for PCI driver interface |
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* |
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* This data only exists for exporting the supported |
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* PCI ids via MODULE_DEVICE_TABLE. We do not actually |
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* register a pci_driver, because someone else might one day |
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* want to register another driver on the same PCI id. |
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*/ |
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static const struct pci_device_id tco_pci_tbl[] = { |
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{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP51_SMBUS, |
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PCI_ANY_ID, PCI_ANY_ID, }, |
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{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP55_SMBUS, |
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PCI_ANY_ID, PCI_ANY_ID, }, |
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{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP78S_SMBUS, |
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PCI_ANY_ID, PCI_ANY_ID, }, |
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{ PCI_VENDOR_ID_NVIDIA, PCI_DEVICE_ID_NVIDIA_NFORCE_MCP79_SMBUS, |
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PCI_ANY_ID, PCI_ANY_ID, }, |
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{ 0, }, /* End of list */ |
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}; |
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MODULE_DEVICE_TABLE(pci, tco_pci_tbl); |
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/* |
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* Init & exit routines |
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*/ |
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static unsigned char nv_tco_getdevice(void) |
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{ |
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struct pci_dev *dev = NULL; |
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u32 val; |
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/* Find the PCI device */ |
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for_each_pci_dev(dev) { |
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if (pci_match_id(tco_pci_tbl, dev) != NULL) { |
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tco_pci = dev; |
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break; |
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} |
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} |
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if (!tco_pci) |
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return 0; |
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/* Find the base io port */ |
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pci_read_config_dword(tco_pci, 0x64, &val); |
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val &= 0xffff; |
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if (val == 0x0001 || val == 0x0000) { |
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/* Something is wrong here, bar isn't setup */ |
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pr_err("failed to get tcobase address\n"); |
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return 0; |
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} |
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val &= 0xff00; |
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tcobase = val + 0x40; |
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if (!request_region(tcobase, 0x10, "NV TCO")) { |
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pr_err("I/O address 0x%04x already in use\n", tcobase); |
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return 0; |
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} |
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/* Set a reasonable heartbeat before we stop the timer */ |
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tco_timer_set_heartbeat(30); |
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/* |
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* Stop the TCO before we change anything so we don't race with |
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* a zeroed timer. |
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*/ |
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tco_timer_keepalive(); |
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tco_timer_stop(); |
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/* Disable SMI caused by TCO */ |
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if (!request_region(MCP51_SMI_EN(tcobase), 4, "NV TCO")) { |
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pr_err("I/O address 0x%04x already in use\n", |
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MCP51_SMI_EN(tcobase)); |
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goto out; |
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} |
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val = inl(MCP51_SMI_EN(tcobase)); |
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val &= ~MCP51_SMI_EN_TCO; |
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outl(val, MCP51_SMI_EN(tcobase)); |
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val = inl(MCP51_SMI_EN(tcobase)); |
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release_region(MCP51_SMI_EN(tcobase), 4); |
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if (val & MCP51_SMI_EN_TCO) { |
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pr_err("Could not disable SMI caused by TCO\n"); |
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goto out; |
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} |
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/* Check chipset's NO_REBOOT bit */ |
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pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); |
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val |= MCP51_SMBUS_SETUP_B_TCO_REBOOT; |
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pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val); |
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pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); |
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if (!(val & MCP51_SMBUS_SETUP_B_TCO_REBOOT)) { |
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pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware\n"); |
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goto out; |
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} |
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return 1; |
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out: |
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release_region(tcobase, 0x10); |
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return 0; |
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} |
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static int nv_tco_init(struct platform_device *dev) |
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{ |
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int ret; |
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/* Check whether or not the hardware watchdog is there */ |
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if (!nv_tco_getdevice()) |
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return -ENODEV; |
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/* Check to see if last reboot was due to watchdog timeout */ |
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pr_info("Watchdog reboot %sdetected\n", |
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inl(TCO_STS(tcobase)) & TCO_STS_TCO2TO_STS ? "" : "not "); |
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/* Clear out the old status */ |
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outl(TCO_STS_RESET, TCO_STS(tcobase)); |
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/* |
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* Check that the heartbeat value is within it's range. |
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* If not, reset to the default. |
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*/ |
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if (tco_timer_set_heartbeat(heartbeat)) { |
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heartbeat = WATCHDOG_HEARTBEAT; |
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tco_timer_set_heartbeat(heartbeat); |
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pr_info("heartbeat value must be 2<heartbeat<39, using %d\n", |
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heartbeat); |
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} |
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ret = misc_register(&nv_tco_miscdev); |
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if (ret != 0) { |
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pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
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WATCHDOG_MINOR, ret); |
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goto unreg_region; |
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} |
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clear_bit(0, &timer_alive); |
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tco_timer_stop(); |
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pr_info("initialized (0x%04x). heartbeat=%d sec (nowayout=%d)\n", |
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tcobase, heartbeat, nowayout); |
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return 0; |
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unreg_region: |
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release_region(tcobase, 0x10); |
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return ret; |
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} |
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static void nv_tco_cleanup(void) |
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{ |
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u32 val; |
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/* Stop the timer before we leave */ |
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if (!nowayout) |
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tco_timer_stop(); |
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/* Set the NO_REBOOT bit to prevent later reboots, just for sure */ |
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pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); |
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val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT; |
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pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val); |
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pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); |
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if (val & MCP51_SMBUS_SETUP_B_TCO_REBOOT) { |
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pr_crit("Couldn't unset REBOOT bit. Machine may soon reset\n"); |
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} |
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/* Deregister */ |
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misc_deregister(&nv_tco_miscdev); |
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release_region(tcobase, 0x10); |
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} |
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static int nv_tco_remove(struct platform_device *dev) |
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{ |
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if (tcobase) |
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nv_tco_cleanup(); |
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return 0; |
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} |
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static void nv_tco_shutdown(struct platform_device *dev) |
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{ |
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u32 val; |
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tco_timer_stop(); |
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/* Some BIOSes fail the POST (once) if the NO_REBOOT flag is not |
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* unset during shutdown. */ |
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pci_read_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, &val); |
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val &= ~MCP51_SMBUS_SETUP_B_TCO_REBOOT; |
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pci_write_config_dword(tco_pci, MCP51_SMBUS_SETUP_B, val); |
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} |
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static struct platform_driver nv_tco_driver = { |
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.probe = nv_tco_init, |
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.remove = nv_tco_remove, |
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.shutdown = nv_tco_shutdown, |
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.driver = { |
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.name = TCO_MODULE_NAME, |
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}, |
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}; |
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static int __init nv_tco_init_module(void) |
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{ |
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int err; |
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pr_info("NV TCO WatchDog Timer Driver v%s\n", TCO_VERSION); |
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err = platform_driver_register(&nv_tco_driver); |
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if (err) |
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return err; |
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nv_tco_platform_device = platform_device_register_simple( |
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TCO_MODULE_NAME, -1, NULL, 0); |
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if (IS_ERR(nv_tco_platform_device)) { |
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err = PTR_ERR(nv_tco_platform_device); |
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goto unreg_platform_driver; |
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} |
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return 0; |
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unreg_platform_driver: |
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platform_driver_unregister(&nv_tco_driver); |
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return err; |
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} |
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static void __exit nv_tco_cleanup_module(void) |
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{ |
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platform_device_unregister(nv_tco_platform_device); |
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platform_driver_unregister(&nv_tco_driver); |
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pr_info("NV TCO Watchdog Module Unloaded\n"); |
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} |
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module_init(nv_tco_init_module); |
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module_exit(nv_tco_cleanup_module); |
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MODULE_AUTHOR("Mike Waychison"); |
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MODULE_DESCRIPTION("TCO timer driver for NV chipsets"); |
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MODULE_LICENSE("GPL");
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