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/*
* sp5100_tco : TCO timer driver for sp5100 chipsets
*
* (c) Copyright 2009 Google Inc., All Rights Reserved.
*
* Based on 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.
*
* See AMD Publication 43009 "AMD SB700/710/750 Register Reference Guide",
* AMD Publication 45482 "AMD SB800-Series Southbridges Register
* Reference Guide"
*/
/*
* Includes, defines, variables, module parameters, ...
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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/platform_device.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include "sp5100_tco.h"
/* Module and version information */
#define TCO_VERSION "0.05"
#define TCO_MODULE_NAME "SP5100 TCO timer"
#define TCO_DRIVER_NAME TCO_MODULE_NAME ", v" TCO_VERSION
/* internal variables */
static u32 tcobase_phys;
static u32 tco_wdt_fired;
static void __iomem *tcobase;
static unsigned int pm_iobase;
static DEFINE_SPINLOCK(tco_lock); /* Guards the hardware */
static unsigned long timer_alive;
static char tco_expect_close;
static struct pci_dev *sp5100_tco_pci;
/* the watchdog platform device */
static struct platform_device *sp5100_tco_platform_device;
/* module parameters */
#define WATCHDOG_HEARTBEAT 60 /* 60 sec default heartbeat. */
static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
__MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started."
" (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
/*
* Some TCO specific functions
*/
static void tco_timer_start(void)
{
u32 val;
unsigned long flags;
spin_lock_irqsave(&tco_lock, flags);
val = readl(SP5100_WDT_CONTROL(tcobase));
val |= SP5100_WDT_START_STOP_BIT;
writel(val, SP5100_WDT_CONTROL(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 = readl(SP5100_WDT_CONTROL(tcobase));
val &= ~SP5100_WDT_START_STOP_BIT;
writel(val, SP5100_WDT_CONTROL(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
}
static void tco_timer_keepalive(void)
{
u32 val;
unsigned long flags;
spin_lock_irqsave(&tco_lock, flags);
val = readl(SP5100_WDT_CONTROL(tcobase));
val |= SP5100_WDT_TRIGGER_BIT;
writel(val, SP5100_WDT_CONTROL(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
}
static int tco_timer_set_heartbeat(int t)
{
unsigned long flags;
if (t < 0 || t > 0xffff)
return -EINVAL;
/* Write new heartbeat to watchdog */
spin_lock_irqsave(&tco_lock, flags);
writel(t, SP5100_WDT_COUNT(tcobase));
spin_unlock_irqrestore(&tco_lock, flags);
heartbeat = t;
return 0;
}
static void tco_timer_enable(void)
{
int val;
if (sp5100_tco_pci->revision >= 0x40) {
/* For SB800 or later */
/* Set the Watchdog timer resolution to 1 sec */
outb(SB800_PM_WATCHDOG_CONFIG, SB800_IO_PM_INDEX_REG);
val = inb(SB800_IO_PM_DATA_REG);
val |= SB800_PM_WATCHDOG_SECOND_RES;
outb(val, SB800_IO_PM_DATA_REG);
/* Enable watchdog decode bit and watchdog timer */
outb(SB800_PM_WATCHDOG_CONTROL, SB800_IO_PM_INDEX_REG);
val = inb(SB800_IO_PM_DATA_REG);
val |= SB800_PCI_WATCHDOG_DECODE_EN;
val &= ~SB800_PM_WATCHDOG_DISABLE;
outb(val, SB800_IO_PM_DATA_REG);
} else {
/* For SP5100 or SB7x0 */
/* Enable watchdog decode bit */
pci_read_config_dword(sp5100_tco_pci,
SP5100_PCI_WATCHDOG_MISC_REG,
&val);
val |= SP5100_PCI_WATCHDOG_DECODE_EN;
pci_write_config_dword(sp5100_tco_pci,
SP5100_PCI_WATCHDOG_MISC_REG,
val);
/* Enable Watchdog timer and set the resolution to 1 sec */
outb(SP5100_PM_WATCHDOG_CONTROL, SP5100_IO_PM_INDEX_REG);
val = inb(SP5100_IO_PM_DATA_REG);
val |= SP5100_PM_WATCHDOG_SECOND_RES;
val &= ~SP5100_PM_WATCHDOG_DISABLE;
outb(val, SP5100_IO_PM_DATA_REG);
}
}
/*
* /dev/watchdog handling
*/
static int sp5100_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_start();
tco_timer_keepalive();
return nonseekable_open(inode, file);
}
static int sp5100_tco_release(struct inode *inode, struct file *file)
{
/* Shut off the timer. */
if (tco_expect_close == 42) {
tco_timer_stop();
} else {
pr_crit("Unexpected close, not stopping watchdog!\n");
tco_timer_keepalive();
}
clear_bit(0, &timer_alive);
tco_expect_close = 0;
return 0;
}
static ssize_t sp5100_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 sp5100_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_start();
tco_timer_keepalive();
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();
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