kernel-ark/drivers/watchdog/sbc7240_wdt.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

314 lines
6.9 KiB
C

/*
* NANO7240 SBC Watchdog device driver
*
* Based on w83877f.c by Scott Jennings,
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation;
*
* Software distributed under the License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* (c) Copyright 2007 Gilles GIGAN <gilles.gigan@jcu.edu.au>
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/miscdevice.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/atomic.h>
#define SBC7240_ENABLE_PORT 0x443
#define SBC7240_DISABLE_PORT 0x043
#define SBC7240_SET_TIMEOUT_PORT SBC7240_ENABLE_PORT
#define SBC7240_MAGIC_CHAR 'V'
#define SBC7240_TIMEOUT 30
#define SBC7240_MAX_TIMEOUT 255
static int timeout = SBC7240_TIMEOUT; /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<="
__MODULE_STRING(SBC7240_MAX_TIMEOUT) ", default="
__MODULE_STRING(SBC7240_TIMEOUT) ")");
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Disable watchdog when closing device file");
#define SBC7240_OPEN_STATUS_BIT 0
#define SBC7240_ENABLED_STATUS_BIT 1
#define SBC7240_EXPECT_CLOSE_STATUS_BIT 2
static unsigned long wdt_status;
/*
* Utility routines
*/
static void wdt_disable(void)
{
/* disable the watchdog */
if (test_and_clear_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
inb_p(SBC7240_DISABLE_PORT);
pr_info("Watchdog timer is now disabled\n");
}
}
static void wdt_enable(void)
{
/* enable the watchdog */
if (!test_and_set_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status)) {
inb_p(SBC7240_ENABLE_PORT);
pr_info("Watchdog timer is now enabled\n");
}
}
static int wdt_set_timeout(int t)
{
if (t < 1 || t > SBC7240_MAX_TIMEOUT) {
pr_err("timeout value must be 1<=x<=%d\n", SBC7240_MAX_TIMEOUT);
return -1;
}
/* set the timeout */
outb_p((unsigned)t, SBC7240_SET_TIMEOUT_PORT);
timeout = t;
pr_info("timeout set to %d seconds\n", t);
return 0;
}
/* Whack the dog */
static inline void wdt_keepalive(void)
{
if (test_bit(SBC7240_ENABLED_STATUS_BIT, &wdt_status))
inb_p(SBC7240_ENABLE_PORT);
}
/*
* /dev/watchdog handling
*/
static ssize_t fop_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
size_t i;
char c;
if (count) {
if (!nowayout) {
clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
&wdt_status);
/* is there a magic char ? */
for (i = 0; i != count; i++) {
if (get_user(c, buf + i))
return -EFAULT;
if (c == SBC7240_MAGIC_CHAR) {
set_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT,
&wdt_status);
break;
}
}
}
wdt_keepalive();
}
return count;
}
static int fop_open(struct inode *inode, struct file *file)
{
if (test_and_set_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status))
return -EBUSY;
wdt_enable();
return nonseekable_open(inode, file);
}
static int fop_close(struct inode *inode, struct file *file)
{
if (test_and_clear_bit(SBC7240_EXPECT_CLOSE_STATUS_BIT, &wdt_status)
|| !nowayout) {
wdt_disable();
} else {
pr_crit("Unexpected close, not stopping watchdog!\n");
wdt_keepalive();
}
clear_bit(SBC7240_OPEN_STATUS_BIT, &wdt_status);
return 0;
}
static const struct watchdog_info ident = {
.options = WDIOF_KEEPALIVEPING|
WDIOF_SETTIMEOUT|
WDIOF_MAGICCLOSE,
.firmware_version = 1,
.identity = "SBC7240",
};
static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case WDIOC_GETSUPPORT:
return copy_to_user((void __user *)arg, &ident, sizeof(ident))
? -EFAULT : 0;
case WDIOC_GETSTATUS:
case WDIOC_GETBOOTSTATUS:
return put_user(0, (int __user *)arg);
case WDIOC_SETOPTIONS:
{
int options;
int retval = -EINVAL;
if (get_user(options, (int __user *)arg))
return -EFAULT;
if (options & WDIOS_DISABLECARD) {
wdt_disable();
retval = 0;
}
if (options & WDIOS_ENABLECARD) {
wdt_enable();
retval = 0;
}
return retval;
}
case WDIOC_KEEPALIVE:
wdt_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
{
int new_timeout;
if (get_user(new_timeout, (int __user *)arg))
return -EFAULT;
if (wdt_set_timeout(new_timeout))
return -EINVAL;
/* Fall through */
}
case WDIOC_GETTIMEOUT:
return put_user(timeout, (int __user *)arg);
default:
return -ENOTTY;
}
}
static const struct file_operations wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = fop_write,
.open = fop_open,
.release = fop_close,
.unlocked_ioctl = fop_ioctl,
};
static struct miscdevice wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &wdt_fops,
};
/*
* Notifier for system down
*/
static int wdt_notify_sys(struct notifier_block *this, unsigned long code,
void *unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
wdt_disable();
return NOTIFY_DONE;
}
static struct notifier_block wdt_notifier = {
.notifier_call = wdt_notify_sys,
};
static void __exit sbc7240_wdt_unload(void)
{
pr_info("Removing watchdog\n");
misc_deregister(&wdt_miscdev);
unregister_reboot_notifier(&wdt_notifier);
release_region(SBC7240_ENABLE_PORT, 1);
}
static int __init sbc7240_wdt_init(void)
{
int rc = -EBUSY;
if (!request_region(SBC7240_ENABLE_PORT, 1, "SBC7240 WDT")) {
pr_err("I/O address 0x%04x already in use\n",
SBC7240_ENABLE_PORT);
rc = -EIO;
goto err_out;
}
/* The IO port 0x043 used to disable the watchdog
* is already claimed by the system timer, so we
* can't request_region() it ...*/
if (timeout < 1 || timeout > SBC7240_MAX_TIMEOUT) {
timeout = SBC7240_TIMEOUT;
pr_info("timeout value must be 1<=x<=%d, using %d\n",
SBC7240_MAX_TIMEOUT, timeout);
}
wdt_set_timeout(timeout);
wdt_disable();
rc = register_reboot_notifier(&wdt_notifier);
if (rc) {
pr_err("cannot register reboot notifier (err=%d)\n", rc);
goto err_out_region;
}
rc = misc_register(&wdt_miscdev);
if (rc) {
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
wdt_miscdev.minor, rc);
goto err_out_reboot_notifier;
}
pr_info("Watchdog driver for SBC7240 initialised (nowayout=%d)\n",
nowayout);
return 0;
err_out_reboot_notifier:
unregister_reboot_notifier(&wdt_notifier);
err_out_region:
release_region(SBC7240_ENABLE_PORT, 1);
err_out:
return rc;
}
module_init(sbc7240_wdt_init);
module_exit(sbc7240_wdt_unload);
MODULE_AUTHOR("Gilles Gigan");
MODULE_DESCRIPTION("Watchdog device driver for single board"
" computers EPIC Nano 7240 from iEi");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);