linux/drivers/watchdog/wdt285.c
Linus Torvalds 0195c00244 Disintegrate and delete asm/system.h
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Merge tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system

Pull "Disintegrate and delete asm/system.h" from David Howells:
 "Here are a bunch of patches to disintegrate asm/system.h into a set of
  separate bits to relieve the problem of circular inclusion
  dependencies.

  I've built all the working defconfigs from all the arches that I can
  and made sure that they don't break.

  The reason for these patches is that I recently encountered a circular
  dependency problem that came about when I produced some patches to
  optimise get_order() by rewriting it to use ilog2().

  This uses bitops - and on the SH arch asm/bitops.h drags in
  asm-generic/get_order.h by a circuituous route involving asm/system.h.

  The main difficulty seems to be asm/system.h.  It holds a number of
  low level bits with no/few dependencies that are commonly used (eg.
  memory barriers) and a number of bits with more dependencies that
  aren't used in many places (eg.  switch_to()).

  These patches break asm/system.h up into the following core pieces:

    (1) asm/barrier.h

        Move memory barriers here.  This already done for MIPS and Alpha.

    (2) asm/switch_to.h

        Move switch_to() and related stuff here.

    (3) asm/exec.h

        Move arch_align_stack() here.  Other process execution related bits
        could perhaps go here from asm/processor.h.

    (4) asm/cmpxchg.h

        Move xchg() and cmpxchg() here as they're full word atomic ops and
        frequently used by atomic_xchg() and atomic_cmpxchg().

    (5) asm/bug.h

        Move die() and related bits.

    (6) asm/auxvec.h

        Move AT_VECTOR_SIZE_ARCH here.

  Other arch headers are created as needed on a per-arch basis."

Fixed up some conflicts from other header file cleanups and moving code
around that has happened in the meantime, so David's testing is somewhat
weakened by that.  We'll find out anything that got broken and fix it..

* tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits)
  Delete all instances of asm/system.h
  Remove all #inclusions of asm/system.h
  Add #includes needed to permit the removal of asm/system.h
  Move all declarations of free_initmem() to linux/mm.h
  Disintegrate asm/system.h for OpenRISC
  Split arch_align_stack() out from asm-generic/system.h
  Split the switch_to() wrapper out of asm-generic/system.h
  Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
  Create asm-generic/barrier.h
  Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h
  Disintegrate asm/system.h for Xtensa
  Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt]
  Disintegrate asm/system.h for Tile
  Disintegrate asm/system.h for Sparc
  Disintegrate asm/system.h for SH
  Disintegrate asm/system.h for Score
  Disintegrate asm/system.h for S390
  Disintegrate asm/system.h for PowerPC
  Disintegrate asm/system.h for PA-RISC
  Disintegrate asm/system.h for MN10300
  ...
2012-03-28 15:58:21 -07:00

233 lines
4.8 KiB
C

/*
* Intel 21285 watchdog driver
* Copyright (c) Phil Blundell <pb@nexus.co.uk>, 1998
*
* based on
*
* SoftDog 0.05: A Software Watchdog Device
*
* (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
* All Rights Reserved.
*
* 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.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/uaccess.h>
#include <linux/irq.h>
#include <mach/hardware.h>
#include <asm/mach-types.h>
#include <asm/system_info.h>
#include <asm/hardware/dec21285.h>
/*
* Define this to stop the watchdog actually rebooting the machine.
*/
#undef ONLY_TESTING
static unsigned int soft_margin = 60; /* in seconds */
static unsigned int reload;
static unsigned long timer_alive;
#ifdef ONLY_TESTING
/*
* If the timer expires..
*/
static void watchdog_fire(int irq, void *dev_id)
{
pr_crit("Would Reboot\n");
*CSR_TIMER4_CNTL = 0;
*CSR_TIMER4_CLR = 0;
}
#endif
/*
* Refresh the timer.
*/
static void watchdog_ping(void)
{
*CSR_TIMER4_LOAD = reload;
}
/*
* Allow only one person to hold it open
*/
static int watchdog_open(struct inode *inode, struct file *file)
{
int ret;
if (*CSR_SA110_CNTL & (1 << 13))
return -EBUSY;
if (test_and_set_bit(1, &timer_alive))
return -EBUSY;
reload = soft_margin * (mem_fclk_21285 / 256);
*CSR_TIMER4_CLR = 0;
watchdog_ping();
*CSR_TIMER4_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD
| TIMER_CNTL_DIV256;
#ifdef ONLY_TESTING
ret = request_irq(IRQ_TIMER4, watchdog_fire, 0, "watchdog", NULL);
if (ret) {
*CSR_TIMER4_CNTL = 0;
clear_bit(1, &timer_alive);
}
#else
/*
* Setting this bit is irreversible; once enabled, there is
* no way to disable the watchdog.
*/
*CSR_SA110_CNTL |= 1 << 13;
ret = 0;
#endif
nonseekable_open(inode, file);
return ret;
}
/*
* Shut off the timer.
* Note: if we really have enabled the watchdog, there
* is no way to turn off.
*/
static int watchdog_release(struct inode *inode, struct file *file)
{
#ifdef ONLY_TESTING
free_irq(IRQ_TIMER4, NULL);
clear_bit(1, &timer_alive);
#endif
return 0;
}
static ssize_t watchdog_write(struct file *file, const char __user *data,
size_t len, loff_t *ppos)
{
/*
* Refresh the timer.
*/
if (len)
watchdog_ping();
return len;
}
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT,
.identity = "Footbridge Watchdog",
};
static long watchdog_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
unsigned int new_margin;
int __user *int_arg = (int __user *)arg;
int ret = -ENOTTY;
switch (cmd) {
case WDIOC_GETSUPPORT:
ret = 0;
if (copy_to_user((void __user *)arg, &ident, sizeof(ident)))
ret = -EFAULT;
break;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
ret = put_user(0, int_arg);
break;
case WDIOC_KEEPALIVE:
watchdog_ping();
ret = 0;
break;
case WDIOC_SETTIMEOUT:
ret = get_user(new_margin, int_arg);
if (ret)
break;
/* Arbitrary, can't find the card's limits */
if (new_margin < 0 || new_margin > 60) {
ret = -EINVAL;
break;
}
soft_margin = new_margin;
reload = soft_margin * (mem_fclk_21285 / 256);
watchdog_ping();
/* Fall */
case WDIOC_GETTIMEOUT:
ret = put_user(soft_margin, int_arg);
break;
}
return ret;
}
static const struct file_operations watchdog_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = watchdog_write,
.unlocked_ioctl = watchdog_ioctl,
.open = watchdog_open,
.release = watchdog_release,
};
static struct miscdevice watchdog_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &watchdog_fops,
};
static int __init footbridge_watchdog_init(void)
{
int retval;
if (machine_is_netwinder())
return -ENODEV;
retval = misc_register(&watchdog_miscdev);
if (retval < 0)
return retval;
pr_info("Footbridge Watchdog Timer: 0.01, timer margin: %d sec\n",
soft_margin);
if (machine_is_cats())
pr_warn("Warning: Watchdog reset may not work on this machine\n");
return 0;
}
static void __exit footbridge_watchdog_exit(void)
{
misc_deregister(&watchdog_miscdev);
}
MODULE_AUTHOR("Phil Blundell <pb@nexus.co.uk>");
MODULE_DESCRIPTION("Footbridge watchdog driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
module_param(soft_margin, int, 0);
MODULE_PARM_DESC(soft_margin, "Watchdog timeout in seconds");
module_init(footbridge_watchdog_init);
module_exit(footbridge_watchdog_exit);