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linux-next/drivers/watchdog/intel_scu_watchdog.c
Jean Delvare 487722cf2d watchdog: Get rid of MODULE_ALIAS_MISCDEV statements
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.

Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.

Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.

On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!

If defining char-major-10-130 is needed then it should happen in
user-space.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
2013-11-17 19:38:13 +01:00

568 lines
15 KiB
C

/*
* 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_pre_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 */
hw_pre_value = ioread32(watchdog_device.timer_load_count_addr);
hw_pre_value = hw_pre_value & 0xFFFF0000;
/* 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;
}
if (!watchdog_device.timer_started) {
/* Just close, since timer has not been started */
pr_debug("closed, without starting timer\n");
return 0;
}
pr_crit("Unexpected close of /dev/watchdog!\n");
/* Since the timer was started, prevent future reopens */
watchdog_device.driver_closed = 1;
/* Refresh the timer for one more interval */
intel_scu_keepalive();
/* Reboot system (if force_boot is set) */
watchdog_fire();
/* We should only reach this point if force_boot is not set */
return 0;
}
static ssize_t intel_scu_write(struct file *file,
char const *data,
size_t len,
loff_t *ppos)
{
if (watchdog_device.timer_started)
/* Watchdog already started, keep it alive */
intel_scu_keepalive();
else
/* Start watchdog with timer value set by init */
intel_scu_set_heartbeat(watchdog_device.timer_set);
return len;
}
static long intel_scu_ioctl(struct file *file,
unsigned int cmd,
unsigned long arg)
{
void __user *argp = (void __user *)arg;
u32 __user *p = argp;
u32 new_margin;
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT
| WDIOF_KEEPALIVEPING,
.firmware_version = 0, /* @todo Get from SCU via
ipc_get_scu_fw_version()? */
.identity = "Intel_SCU IOH Watchdog" /* len < 32 */
};
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:
intel_scu_keepalive();
return 0;
case WDIOC_SETTIMEOUT:
if (get_user(new_margin, p))
return -EFAULT;
if (check_timer_margin(new_margin))
return -EINVAL;
if (intel_scu_set_heartbeat(new_margin))
return -EINVAL;
return 0;
case WDIOC_GETTIMEOUT:
return put_user(watchdog_device.soft_threshold, p);
default:
return -ENOTTY;
}
}
/*
* Notifier for system down
*/
static int intel_scu_notify_sys(struct notifier_block *this,
unsigned long code,
void *another_unused)
{
if (code == SYS_DOWN || code == SYS_HALT)
/* Turn off the watchdog timer. */
intel_scu_stop();
return NOTIFY_DONE;
}
/*
* Kernel Interfaces
*/
static const struct file_operations intel_scu_fops = {
.owner = THIS_MODULE,
.llseek = no_llseek,
.write = intel_scu_write,
.unlocked_ioctl = intel_scu_ioctl,
.open = intel_scu_open,
.release = intel_scu_release,
};
static int __init intel_scu_watchdog_init(void)
{
int ret;
u32 __iomem *tmp_addr;
/*
* We don't really need to check this as the SFI timer get will fail
* but if we do so we can exit with a clearer reason and no noise.
*
* If it isn't an intel MID device then it doesn't have this watchdog
*/
if (!intel_mid_identify_cpu())
return -ENODEV;
/* Check boot parameters to verify that their initial values */
/* are in range. */
/* Check value of timer_set boot parameter */
if ((timer_set < MIN_TIME_CYCLE) ||
(timer_set > MAX_TIME - MIN_TIME_CYCLE)) {
pr_err("value of timer_set %x (hex) is out of range from %x to %x (hex)\n",
timer_set, MIN_TIME_CYCLE, MAX_TIME - MIN_TIME_CYCLE);
return -EINVAL;
}
/* Check value of timer_margin boot parameter */
if (check_timer_margin(timer_margin))
return -EINVAL;
watchdog_device.timer_tbl_ptr = sfi_get_mtmr(sfi_mtimer_num-1);
if (watchdog_device.timer_tbl_ptr == NULL) {
pr_debug("timer is not available\n");
return -ENODEV;
}
/* make sure the timer exists */
if (watchdog_device.timer_tbl_ptr->phys_addr == 0) {
pr_debug("timer %d does not have valid physical memory\n",
sfi_mtimer_num);
return -ENODEV;
}
if (watchdog_device.timer_tbl_ptr->irq == 0) {
pr_debug("timer %d invalid irq\n", sfi_mtimer_num);
return -ENODEV;
}
tmp_addr = ioremap_nocache(watchdog_device.timer_tbl_ptr->phys_addr,
20);
if (tmp_addr == NULL) {
pr_debug("timer unable to ioremap\n");
return -ENOMEM;
}
watchdog_device.timer_load_count_addr = tmp_addr++;
watchdog_device.timer_current_value_addr = tmp_addr++;
watchdog_device.timer_control_addr = tmp_addr++;
watchdog_device.timer_clear_interrupt_addr = tmp_addr++;
watchdog_device.timer_interrupt_status_addr = tmp_addr++;
/* Set the default time values in device structure */
watchdog_device.timer_set = timer_set;
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;
watchdog_device.intel_scu_notifier.notifier_call =
intel_scu_notify_sys;
ret = register_reboot_notifier(&watchdog_device.intel_scu_notifier);
if (ret) {
pr_err("cannot register notifier %d)\n", ret);
goto register_reboot_error;
}
watchdog_device.miscdev.minor = WATCHDOG_MINOR;
watchdog_device.miscdev.name = "watchdog";
watchdog_device.miscdev.fops = &intel_scu_fops;
ret = misc_register(&watchdog_device.miscdev);
if (ret) {
pr_err("cannot register miscdev %d err =%d\n",
WATCHDOG_MINOR, ret);
goto misc_register_error;
}
ret = request_irq((unsigned int)watchdog_device.timer_tbl_ptr->irq,
watchdog_timer_interrupt,
IRQF_SHARED, "watchdog",
&watchdog_device.timer_load_count_addr);
if (ret) {
pr_err("error requesting irq %d\n", ret);
goto request_irq_error;
}
/* Make sure timer is disabled before returning */
intel_scu_stop();
return 0;
/* error cleanup */
request_irq_error:
misc_deregister(&watchdog_device.miscdev);
misc_register_error:
unregister_reboot_notifier(&watchdog_device.intel_scu_notifier);
register_reboot_error:
intel_scu_stop();
iounmap(watchdog_device.timer_load_count_addr);
return ret;
}
static void __exit intel_scu_watchdog_exit(void)
{
misc_deregister(&watchdog_device.miscdev);
unregister_reboot_notifier(&watchdog_device.intel_scu_notifier);
/* disable the timer */
iowrite32(0x00000002, watchdog_device.timer_control_addr);
iounmap(watchdog_device.timer_load_count_addr);
}
late_initcall(intel_scu_watchdog_init);
module_exit(intel_scu_watchdog_exit);
MODULE_AUTHOR("Intel Corporation");
MODULE_DESCRIPTION("Intel SCU Watchdog Device Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION(WDT_VER);