linux/drivers/watchdog/booke_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

304 lines
7.4 KiB
C

/*
* Watchdog timer for PowerPC Book-E systems
*
* Author: Matthew McClintock
* Maintainer: Kumar Gala <galak@kernel.crashing.org>
*
* Copyright 2005, 2008, 2010-2011 Freescale Semiconductor Inc.
*
* 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/fs.h>
#include <linux/smp.h>
#include <linux/miscdevice.h>
#include <linux/notifier.h>
#include <linux/watchdog.h>
#include <linux/uaccess.h>
#include <asm/reg_booke.h>
#include <asm/time.h>
#include <asm/div64.h>
/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
* Also, the wdt_period sets the watchdog timer period timeout.
* For E500 cpus the wdt_period sets which bit changing from 0->1 will
* trigger a watchog timeout. This watchdog timeout will occur 3 times, the
* first time nothing will happen, the second time a watchdog exception will
* occur, and the final time the board will reset.
*/
u32 booke_wdt_enabled;
u32 booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT;
#ifdef CONFIG_FSL_BOOKE
#define WDTP(x) ((((x)&0x3)<<30)|(((x)&0x3c)<<15))
#define WDTP_MASK (WDTP(0x3f))
#else
#define WDTP(x) (TCR_WP(x))
#define WDTP_MASK (TCR_WP_MASK)
#endif
static DEFINE_SPINLOCK(booke_wdt_lock);
/* For the specified period, determine the number of seconds
* corresponding to the reset time. There will be a watchdog
* exception at approximately 3/5 of this time.
*
* The formula to calculate this is given by:
* 2.5 * (2^(63-period+1)) / timebase_freq
*
* In order to simplify things, we assume that period is
* at least 1. This will still result in a very long timeout.
*/
static unsigned long long period_to_sec(unsigned int period)
{
unsigned long long tmp = 1ULL << (64 - period);
unsigned long tmp2 = ppc_tb_freq;
/* tmp may be a very large number and we don't want to overflow,
* so divide the timebase freq instead of multiplying tmp
*/
tmp2 = tmp2 / 5 * 2;
do_div(tmp, tmp2);
return tmp;
}
/*
* This procedure will find the highest period which will give a timeout
* greater than the one required. e.g. for a bus speed of 66666666 and
* and a parameter of 2 secs, then this procedure will return a value of 38.
*/
static unsigned int sec_to_period(unsigned int secs)
{
unsigned int period;
for (period = 63; period > 0; period--) {
if (period_to_sec(period) >= secs)
return period;
}
return 0;
}
static void __booke_wdt_set(void *data)
{
u32 val;
val = mfspr(SPRN_TCR);
val &= ~WDTP_MASK;
val |= WDTP(booke_wdt_period);
mtspr(SPRN_TCR, val);
}
static void booke_wdt_set(void)
{
on_each_cpu(__booke_wdt_set, NULL, 0);
}
static void __booke_wdt_ping(void *data)
{
mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
}
static void booke_wdt_ping(void)
{
on_each_cpu(__booke_wdt_ping, NULL, 0);
}
static void __booke_wdt_enable(void *data)
{
u32 val;
/* clear status before enabling watchdog */
__booke_wdt_ping(NULL);
val = mfspr(SPRN_TCR);
val &= ~WDTP_MASK;
val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period));
mtspr(SPRN_TCR, val);
}
/**
* booke_wdt_disable - disable the watchdog on the given CPU
*
* This function is called on each CPU. It disables the watchdog on that CPU.
*
* TCR[WRC] cannot be changed once it has been set to non-zero, but we can
* effectively disable the watchdog by setting its period to the maximum value.
*/
static void __booke_wdt_disable(void *data)
{
u32 val;
val = mfspr(SPRN_TCR);
val &= ~(TCR_WIE | WDTP_MASK);
mtspr(SPRN_TCR, val);
/* clear status to make sure nothing is pending */
__booke_wdt_ping(NULL);
}
static ssize_t booke_wdt_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
booke_wdt_ping();
return count;
}
static struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
.identity = "PowerPC Book-E Watchdog",
};
static long booke_wdt_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
u32 tmp = 0;
u32 __user *p = (u32 __user *)arg;
switch (cmd) {
case WDIOC_GETSUPPORT:
if (copy_to_user((void *)arg, &ident, sizeof(ident)))
return -EFAULT;
case WDIOC_GETSTATUS:
return put_user(0, p);
case WDIOC_GETBOOTSTATUS:
/* XXX: something is clearing TSR */
tmp = mfspr(SPRN_TSR) & TSR_WRS(3);
/* returns CARDRESET if last reset was caused by the WDT */
return (tmp ? WDIOF_CARDRESET : 0);
case WDIOC_SETOPTIONS:
if (get_user(tmp, p))
return -EINVAL;
if (tmp == WDIOS_ENABLECARD) {
booke_wdt_ping();
break;
} else
return -EINVAL;
return 0;
case WDIOC_KEEPALIVE:
booke_wdt_ping();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(tmp, p))
return -EFAULT;
#ifdef CONFIG_FSL_BOOKE
/* period of 1 gives the largest possible timeout */
if (tmp > period_to_sec(1))
return -EINVAL;
booke_wdt_period = sec_to_period(tmp);
#else
booke_wdt_period = tmp;
#endif
booke_wdt_set();
/* Fall */
case WDIOC_GETTIMEOUT:
#ifdef CONFIG_FSL_BOOKE
return put_user(period_to_sec(booke_wdt_period), p);
#else
return put_user(booke_wdt_period, p);
#endif
default:
return -ENOTTY;
}
return 0;
}
/* wdt_is_active stores wether or not the /dev/watchdog device is opened */
static unsigned long wdt_is_active;
static int booke_wdt_open(struct inode *inode, struct file *file)
{
/* /dev/watchdog can only be opened once */
if (test_and_set_bit(0, &wdt_is_active))
return -EBUSY;
spin_lock(&booke_wdt_lock);
if (booke_wdt_enabled == 0) {
booke_wdt_enabled = 1;
on_each_cpu(__booke_wdt_enable, NULL, 0);
pr_debug("watchdog enabled (timeout = %llu sec)\n",
period_to_sec(booke_wdt_period));
}
spin_unlock(&booke_wdt_lock);
return nonseekable_open(inode, file);
}
static int booke_wdt_release(struct inode *inode, struct file *file)
{
#ifndef CONFIG_WATCHDOG_NOWAYOUT
/* Normally, the watchdog is disabled when /dev/watchdog is closed, but
* if CONFIG_WATCHDOG_NOWAYOUT is defined, then it means that the
* watchdog should remain enabled. So we disable it only if
* CONFIG_WATCHDOG_NOWAYOUT is not defined.
*/
on_each_cpu(__booke_wdt_disable, NULL, 0);
booke_wdt_enabled = 0;
pr_debug("watchdog disabled\n");
#endif
clear_bit(0, &wdt_is_active);
return 0;
}
static const struct file_operations booke_wdt_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = booke_wdt_write,
.unlocked_ioctl = booke_wdt_ioctl,
.open = booke_wdt_open,
.release = booke_wdt_release,
};
static struct miscdevice booke_wdt_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &booke_wdt_fops,
};
static void __exit booke_wdt_exit(void)
{
misc_deregister(&booke_wdt_miscdev);
}
static int __init booke_wdt_init(void)
{
int ret = 0;
pr_info("powerpc book-e watchdog driver loaded\n");
ident.firmware_version = cur_cpu_spec->pvr_value;
ret = misc_register(&booke_wdt_miscdev);
if (ret) {
pr_err("cannot register device (minor=%u, ret=%i)\n",
WATCHDOG_MINOR, ret);
return ret;
}
spin_lock(&booke_wdt_lock);
if (booke_wdt_enabled == 1) {
pr_info("watchdog enabled (timeout = %llu sec)\n",
period_to_sec(booke_wdt_period));
on_each_cpu(__booke_wdt_enable, NULL, 0);
}
spin_unlock(&booke_wdt_lock);
return ret;
}
module_init(booke_wdt_init);
module_exit(booke_wdt_exit);
MODULE_DESCRIPTION("PowerPC Book-E watchdog driver");
MODULE_LICENSE("GPL");