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/*
* Intel_SCU 0.2: An Intel SCU IOH Based Watchdog Device
* for Intel part #(s):
* - AF82MP20 PCH
*
* Copyright (C) 2009-2010 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General
* Public License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be
* useful, but WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
* PURPOSE. See the GNU General Public License for more details.
* You should have received a copy of the GNU General Public
* License along with this program; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
* The full GNU General Public License is included in this
* distribution in the file called COPYING.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/fs.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/uaccess.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/sfi.h>
#include <asm/irq.h>
#include <linux/atomic.h>
#include <asm/intel_scu_ipc.h>
#include <asm/apb_timer.h>
#include <asm/intel-mid.h>
#include "intel_scu_watchdog.h"
/* Bounds number of times we will retry loading time count */
/* This retry is a work around for a silicon bug. */
#define MAX_RETRY 16
#define IPC_SET_WATCHDOG_TIMER 0xF8
static int timer_margin = DEFAULT_SOFT_TO_HARD_MARGIN;
module_param(timer_margin, int, 0);
MODULE_PARM_DESC(timer_margin,
"Watchdog timer margin"
"Time between interrupt and resetting the system"
"The range is from 1 to 160"
"This is the time for all keep alives to arrive");
static int timer_set = DEFAULT_TIME;
module_param(timer_set, int, 0);
MODULE_PARM_DESC(timer_set,
"Default Watchdog timer setting"
"Complete cycle time"
"The range is from 1 to 170"
"This is the time for all keep alives to arrive");
/* After watchdog device is closed, check force_boot. If:
* force_boot == 0, then force boot on next watchdog interrupt after close,
* force_boot == 1, then force boot immediately when device is closed.
*/
static int force_boot;
module_param(force_boot, int, 0);
MODULE_PARM_DESC(force_boot,
"A value of 1 means that the driver will reboot"
"the system immediately if the /dev/watchdog device is closed"
"A value of 0 means that when /dev/watchdog device is closed"
"the watchdog timer will be refreshed for one more interval"
"of length: timer_set. At the end of this interval, the"
"watchdog timer will reset the system."
);
/* there is only one device in the system now; this can be made into
* an array in the future if we have more than one device */
static struct intel_scu_watchdog_dev watchdog_device;
/* Forces restart, if force_reboot is set */
static void watchdog_fire(void)
{
if (force_boot) {
pr_crit("Initiating system reboot\n");
emergency_restart();
pr_crit("Reboot didn't ?????\n");
}
else {
pr_crit("Immediate Reboot Disabled\n");
pr_crit("System will reset when watchdog timer times out!\n");
}
}
static int check_timer_margin(int new_margin)
{
if ((new_margin < MIN_TIME_CYCLE) ||
(new_margin > MAX_TIME - timer_set)) {
pr_debug("value of new_margin %d is out of the range %d to %d\n",
new_margin, MIN_TIME_CYCLE, MAX_TIME - timer_set);
return -EINVAL;
}
return 0;
}
/*
* IPC operations
*/
static int watchdog_set_ipc(int soft_threshold, int threshold)
{
u32 *ipc_wbuf;
u8 cbuf[16] = { '\0' };
int ipc_ret = 0;
ipc_wbuf = (u32 *)&cbuf;
ipc_wbuf[0] = soft_threshold;
ipc_wbuf[1] = threshold;
ipc_ret = intel_scu_ipc_command(
IPC_SET_WATCHDOG_TIMER,
0,
ipc_wbuf,
2,
NULL,
0);
if (ipc_ret != 0)
pr_err("Error setting SCU watchdog timer: %x\n", ipc_ret);
return ipc_ret;
};
/*
* Intel_SCU operations
*/
/* timer interrupt handler */
static irqreturn_t watchdog_timer_interrupt(int irq, void *dev_id)
{
int int_status;
int_status = ioread32(watchdog_device.timer_interrupt_status_addr);
pr_debug("irq, int_status: %x\n", int_status);
if (int_status != 0)
return IRQ_NONE;
/* has the timer been started? If not, then this is spurious */
if (watchdog_device.timer_started == 0) {
pr_debug("spurious interrupt received\n");
return IRQ_HANDLED;
}
/* temporarily disable the timer */
iowrite32(0x00000002, watchdog_device.timer_control_addr);
/* set the timer to the threshold */
iowrite32(watchdog_device.threshold,
watchdog_device.timer_load_count_addr);
/* allow the timer to run */
iowrite32(0x00000003, watchdog_device.timer_control_addr);
return IRQ_HANDLED;
}
static int intel_scu_keepalive(void)
{
/* read eoi register - clears interrupt */
ioread32(watchdog_device.timer_clear_interrupt_addr);
/* temporarily disable the timer */
iowrite32(0x00000002, watchdog_device.timer_control_addr);
/* set the timer to the soft_threshold */
iowrite32(watchdog_device.soft_threshold,
watchdog_device.timer_load_count_addr);
/* allow the timer to run */
iowrite32(0x00000003, watchdog_device.timer_control_addr);
return 0;
}
static int intel_scu_stop(void)
{
iowrite32(0, watchdog_device.timer_control_addr);
return 0;
}
static int intel_scu_set_heartbeat(u32 t)
{
int ipc_ret;
int retry_count;
u32 soft_value;
u32 hw_value;
watchdog_device.timer_set = t;
watchdog_device.threshold =
timer_margin * watchdog_device.timer_tbl_ptr->freq_hz;
watchdog_device.soft_threshold =
(watchdog_device.timer_set - timer_margin)
* watchdog_device.timer_tbl_ptr->freq_hz;
pr_debug("set_heartbeat: timer freq is %d\n",
watchdog_device.timer_tbl_ptr->freq_hz);
pr_debug("set_heartbeat: timer_set is %x (hex)\n",
watchdog_device.timer_set);
pr_debug("set_hearbeat: timer_margin is %x (hex)\n", timer_margin);
pr_debug("set_heartbeat: threshold is %x (hex)\n",
watchdog_device.threshold);
pr_debug("set_heartbeat: soft_threshold is %x (hex)\n",
watchdog_device.soft_threshold);
/* Adjust thresholds by FREQ_ADJUSTMENT factor, to make the */
/* watchdog timing come out right. */
watchdog_device.threshold =
watchdog_device.threshold / FREQ_ADJUSTMENT;
watchdog_device.soft_threshold =
watchdog_device.soft_threshold / FREQ_ADJUSTMENT;
/* temporarily disable the timer */
iowrite32(0x00000002, watchdog_device.timer_control_addr);
/* send the threshold and soft_threshold via IPC to the processor */
ipc_ret = watchdog_set_ipc(watchdog_device.soft_threshold,
watchdog_device.threshold);
if (ipc_ret != 0) {
/* Make sure the watchdog timer is stopped */
intel_scu_stop();
return ipc_ret;
}
/* Soft Threshold set loop. Early versions of silicon did */
/* not always set this count correctly. This loop checks */
/* the value and retries if it was not set correctly. */
retry_count = 0;
soft_value = watchdog_device.soft_threshold & 0xFFFF0000;
do {
/* Make sure timer is stopped */
intel_scu_stop();
if (MAX_RETRY < retry_count++) {
/* Unable to set timer value */
pr_err("Unable to set timer\n");
return -ENODEV;
}
/* set the timer to the soft threshold */
iowrite32(watchdog_device.soft_threshold,
watchdog_device.timer_load_count_addr);
/* read count value before starting timer */
ioread32(watchdog_device.timer_load_count_addr);
/* Start the timer */
iowrite32(0x00000003, watchdog_device.timer_control_addr);
/* read the value the time loaded into its count reg */
hw_value = ioread32(watchdog_device.timer_load_count_addr);
hw_value = hw_value & 0xFFFF0000;
} while (soft_value != hw_value);
watchdog_device.timer_started = 1;
return 0;
}
/*
* /dev/watchdog handling
*/
static int intel_scu_open(struct inode *inode, struct file *file)
{
/* Set flag to indicate that watchdog device is open */
if (test_and_set_bit(0, &watchdog_device.driver_open))
return -EBUSY;
/* Check for reopen of driver. Reopens are not allowed */
if (watchdog_device.driver_closed)
return -EPERM;
return nonseekable_open(inode, file);
}
static int intel_scu_release(struct inode *inode, struct file *file)
{
/*
* This watchdog should not be closed, after the timer
* is started with the WDIPC_SETTIMEOUT ioctl
* If force_boot is set watchdog_fire() will cause an
* immediate reset. If force_boot is not set, the watchdog
* timer is refreshed for one more interval. At the end
* of that interval, the watchdog timer will reset the system.
*/
if (!test_and_clear_bit(0, &watchdog_device.driver_open)) {
pr_debug("intel_scu_release, without open\n");
return -ENOTTY;
}
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