b1608d69cb
Commit b826291c, "drivercore/dt: add a match table pointer to struct
device" added an of_match pointer to struct device to cache the
of_match_table entry discovered at driver match time. This was unsafe
because matching is not an atomic operation with probing a driver. If
two or more drivers are attempted to be matched to a driver at the
same time, then the cached matching entry pointer could get
overwritten.
This patch reverts the of_match cache pointer and reworks all users to
call of_match_device() directly instead.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
332 lines
8.1 KiB
C
332 lines
8.1 KiB
C
/*
|
|
* mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface
|
|
*
|
|
* Authors: Dave Updegraff <dave@cray.org>
|
|
* Kumar Gala <galak@kernel.crashing.org>
|
|
* Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org>
|
|
* ..and from sc520_wdt
|
|
* Copyright (c) 2008 MontaVista Software, Inc.
|
|
* Anton Vorontsov <avorontsov@ru.mvista.com>
|
|
*
|
|
* Note: it appears that you can only actually ENABLE or DISABLE the thing
|
|
* once after POR. Once enabled, you cannot disable, and vice versa.
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include <linux/fs.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/timer.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/of_platform.h>
|
|
#include <linux/module.h>
|
|
#include <linux/watchdog.h>
|
|
#include <linux/io.h>
|
|
#include <linux/uaccess.h>
|
|
#include <sysdev/fsl_soc.h>
|
|
|
|
struct mpc8xxx_wdt {
|
|
__be32 res0;
|
|
__be32 swcrr; /* System watchdog control register */
|
|
#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */
|
|
#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */
|
|
#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/
|
|
#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */
|
|
__be32 swcnr; /* System watchdog count register */
|
|
u8 res1[2];
|
|
__be16 swsrr; /* System watchdog service register */
|
|
u8 res2[0xF0];
|
|
};
|
|
|
|
struct mpc8xxx_wdt_type {
|
|
int prescaler;
|
|
bool hw_enabled;
|
|
};
|
|
|
|
static struct mpc8xxx_wdt __iomem *wd_base;
|
|
static int mpc8xxx_wdt_init_late(void);
|
|
|
|
static u16 timeout = 0xffff;
|
|
module_param(timeout, ushort, 0);
|
|
MODULE_PARM_DESC(timeout,
|
|
"Watchdog timeout in ticks. (0<timeout<65536, default=65535)");
|
|
|
|
static int reset = 1;
|
|
module_param(reset, bool, 0);
|
|
MODULE_PARM_DESC(reset,
|
|
"Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset");
|
|
|
|
static int nowayout = WATCHDOG_NOWAYOUT;
|
|
module_param(nowayout, int, 0);
|
|
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
|
|
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
|
|
|
|
/*
|
|
* We always prescale, but if someone really doesn't want to they can set this
|
|
* to 0
|
|
*/
|
|
static int prescale = 1;
|
|
static unsigned int timeout_sec;
|
|
|
|
static unsigned long wdt_is_open;
|
|
static DEFINE_SPINLOCK(wdt_spinlock);
|
|
|
|
static void mpc8xxx_wdt_keepalive(void)
|
|
{
|
|
/* Ping the WDT */
|
|
spin_lock(&wdt_spinlock);
|
|
out_be16(&wd_base->swsrr, 0x556c);
|
|
out_be16(&wd_base->swsrr, 0xaa39);
|
|
spin_unlock(&wdt_spinlock);
|
|
}
|
|
|
|
static void mpc8xxx_wdt_timer_ping(unsigned long arg);
|
|
static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0);
|
|
|
|
static void mpc8xxx_wdt_timer_ping(unsigned long arg)
|
|
{
|
|
mpc8xxx_wdt_keepalive();
|
|
/* We're pinging it twice faster than needed, just to be sure. */
|
|
mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2);
|
|
}
|
|
|
|
static void mpc8xxx_wdt_pr_warn(const char *msg)
|
|
{
|
|
pr_crit("mpc8xxx_wdt: %s, expect the %s soon!\n", msg,
|
|
reset ? "reset" : "machine check exception");
|
|
}
|
|
|
|
static ssize_t mpc8xxx_wdt_write(struct file *file, const char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
if (count)
|
|
mpc8xxx_wdt_keepalive();
|
|
return count;
|
|
}
|
|
|
|
static int mpc8xxx_wdt_open(struct inode *inode, struct file *file)
|
|
{
|
|
u32 tmp = SWCRR_SWEN;
|
|
if (test_and_set_bit(0, &wdt_is_open))
|
|
return -EBUSY;
|
|
|
|
/* Once we start the watchdog we can't stop it */
|
|
if (nowayout)
|
|
__module_get(THIS_MODULE);
|
|
|
|
/* Good, fire up the show */
|
|
if (prescale)
|
|
tmp |= SWCRR_SWPR;
|
|
if (reset)
|
|
tmp |= SWCRR_SWRI;
|
|
|
|
tmp |= timeout << 16;
|
|
|
|
out_be32(&wd_base->swcrr, tmp);
|
|
|
|
del_timer_sync(&wdt_timer);
|
|
|
|
return nonseekable_open(inode, file);
|
|
}
|
|
|
|
static int mpc8xxx_wdt_release(struct inode *inode, struct file *file)
|
|
{
|
|
if (!nowayout)
|
|
mpc8xxx_wdt_timer_ping(0);
|
|
else
|
|
mpc8xxx_wdt_pr_warn("watchdog closed");
|
|
clear_bit(0, &wdt_is_open);
|
|
return 0;
|
|
}
|
|
|
|
static long mpc8xxx_wdt_ioctl(struct file *file, unsigned int cmd,
|
|
unsigned long arg)
|
|
{
|
|
void __user *argp = (void __user *)arg;
|
|
int __user *p = argp;
|
|
static const struct watchdog_info ident = {
|
|
.options = WDIOF_KEEPALIVEPING,
|
|
.firmware_version = 1,
|
|
.identity = "MPC8xxx",
|
|
};
|
|
|
|
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_KEEPALIVE:
|
|
mpc8xxx_wdt_keepalive();
|
|
return 0;
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(timeout_sec, p);
|
|
default:
|
|
return -ENOTTY;
|
|
}
|
|
}
|
|
|
|
static const struct file_operations mpc8xxx_wdt_fops = {
|
|
.owner = THIS_MODULE,
|
|
.llseek = no_llseek,
|
|
.write = mpc8xxx_wdt_write,
|
|
.unlocked_ioctl = mpc8xxx_wdt_ioctl,
|
|
.open = mpc8xxx_wdt_open,
|
|
.release = mpc8xxx_wdt_release,
|
|
};
|
|
|
|
static struct miscdevice mpc8xxx_wdt_miscdev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &mpc8xxx_wdt_fops,
|
|
};
|
|
|
|
static const struct of_device_id mpc8xxx_wdt_match[];
|
|
static int __devinit mpc8xxx_wdt_probe(struct platform_device *ofdev)
|
|
{
|
|
int ret;
|
|
const struct of_device_id *match;
|
|
struct device_node *np = ofdev->dev.of_node;
|
|
struct mpc8xxx_wdt_type *wdt_type;
|
|
u32 freq = fsl_get_sys_freq();
|
|
bool enabled;
|
|
|
|
match = of_match_device(mpc8xxx_wdt_match, &ofdev->dev);
|
|
if (!match)
|
|
return -EINVAL;
|
|
wdt_type = match->data;
|
|
|
|
if (!freq || freq == -1)
|
|
return -EINVAL;
|
|
|
|
wd_base = of_iomap(np, 0);
|
|
if (!wd_base)
|
|
return -ENOMEM;
|
|
|
|
enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN;
|
|
if (!enabled && wdt_type->hw_enabled) {
|
|
pr_info("mpc8xxx_wdt: could not be enabled in software\n");
|
|
ret = -ENOSYS;
|
|
goto err_unmap;
|
|
}
|
|
|
|
/* Calculate the timeout in seconds */
|
|
if (prescale)
|
|
timeout_sec = (timeout * wdt_type->prescaler) / freq;
|
|
else
|
|
timeout_sec = timeout / freq;
|
|
|
|
#ifdef MODULE
|
|
ret = mpc8xxx_wdt_init_late();
|
|
if (ret)
|
|
goto err_unmap;
|
|
#endif
|
|
|
|
pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d "
|
|
"(%d seconds)\n", reset ? "reset" : "interrupt", timeout,
|
|
timeout_sec);
|
|
|
|
/*
|
|
* If the watchdog was previously enabled or we're running on
|
|
* MPC8xxx, we should ping the wdt from the kernel until the
|
|
* userspace handles it.
|
|
*/
|
|
if (enabled)
|
|
mpc8xxx_wdt_timer_ping(0);
|
|
return 0;
|
|
err_unmap:
|
|
iounmap(wd_base);
|
|
wd_base = NULL;
|
|
return ret;
|
|
}
|
|
|
|
static int __devexit mpc8xxx_wdt_remove(struct platform_device *ofdev)
|
|
{
|
|
mpc8xxx_wdt_pr_warn("watchdog removed");
|
|
del_timer_sync(&wdt_timer);
|
|
misc_deregister(&mpc8xxx_wdt_miscdev);
|
|
iounmap(wd_base);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct of_device_id mpc8xxx_wdt_match[] = {
|
|
{
|
|
.compatible = "mpc83xx_wdt",
|
|
.data = &(struct mpc8xxx_wdt_type) {
|
|
.prescaler = 0x10000,
|
|
},
|
|
},
|
|
{
|
|
.compatible = "fsl,mpc8610-wdt",
|
|
.data = &(struct mpc8xxx_wdt_type) {
|
|
.prescaler = 0x10000,
|
|
.hw_enabled = true,
|
|
},
|
|
},
|
|
{
|
|
.compatible = "fsl,mpc823-wdt",
|
|
.data = &(struct mpc8xxx_wdt_type) {
|
|
.prescaler = 0x800,
|
|
},
|
|
},
|
|
{},
|
|
};
|
|
MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match);
|
|
|
|
static struct platform_driver mpc8xxx_wdt_driver = {
|
|
.probe = mpc8xxx_wdt_probe,
|
|
.remove = __devexit_p(mpc8xxx_wdt_remove),
|
|
.driver = {
|
|
.name = "mpc8xxx_wdt",
|
|
.owner = THIS_MODULE,
|
|
.of_match_table = mpc8xxx_wdt_match,
|
|
},
|
|
};
|
|
|
|
/*
|
|
* We do wdt initialization in two steps: arch_initcall probes the wdt
|
|
* very early to start pinging the watchdog (misc devices are not yet
|
|
* available), and later module_init() just registers the misc device.
|
|
*/
|
|
static int mpc8xxx_wdt_init_late(void)
|
|
{
|
|
int ret;
|
|
|
|
if (!wd_base)
|
|
return -ENODEV;
|
|
|
|
ret = misc_register(&mpc8xxx_wdt_miscdev);
|
|
if (ret) {
|
|
pr_err("cannot register miscdev on minor=%d (err=%d)\n",
|
|
WATCHDOG_MINOR, ret);
|
|
return ret;
|
|
}
|
|
return 0;
|
|
}
|
|
#ifndef MODULE
|
|
module_init(mpc8xxx_wdt_init_late);
|
|
#endif
|
|
|
|
static int __init mpc8xxx_wdt_init(void)
|
|
{
|
|
return platform_driver_register(&mpc8xxx_wdt_driver);
|
|
}
|
|
arch_initcall(mpc8xxx_wdt_init);
|
|
|
|
static void __exit mpc8xxx_wdt_exit(void)
|
|
{
|
|
platform_driver_unregister(&mpc8xxx_wdt_driver);
|
|
}
|
|
module_exit(mpc8xxx_wdt_exit);
|
|
|
|
MODULE_AUTHOR("Dave Updegraff, Kumar Gala");
|
|
MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx "
|
|
"uProcessors");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|