![Kay Sievers](/assets/img/avatar_default.png)
All kobjects require a dynamically allocated name now. We no longer need to keep track if the name is statically assigned, we can just unconditionally free() all kobject names on cleanup. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
511 lines
13 KiB
C
511 lines
13 KiB
C
/*
|
|
* linux/kernel/time/clocksource.c
|
|
*
|
|
* This file contains the functions which manage clocksource drivers.
|
|
*
|
|
* Copyright (C) 2004, 2005 IBM, John Stultz (johnstul@us.ibm.com)
|
|
*
|
|
* 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.
|
|
*
|
|
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*
|
|
* TODO WishList:
|
|
* o Allow clocksource drivers to be unregistered
|
|
* o get rid of clocksource_jiffies extern
|
|
*/
|
|
|
|
#include <linux/clocksource.h>
|
|
#include <linux/sysdev.h>
|
|
#include <linux/init.h>
|
|
#include <linux/module.h>
|
|
#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
|
|
#include <linux/tick.h>
|
|
|
|
/* XXX - Would like a better way for initializing curr_clocksource */
|
|
extern struct clocksource clocksource_jiffies;
|
|
|
|
/*[Clocksource internal variables]---------
|
|
* curr_clocksource:
|
|
* currently selected clocksource. Initialized to clocksource_jiffies.
|
|
* next_clocksource:
|
|
* pending next selected clocksource.
|
|
* clocksource_list:
|
|
* linked list with the registered clocksources
|
|
* clocksource_lock:
|
|
* protects manipulations to curr_clocksource and next_clocksource
|
|
* and the clocksource_list
|
|
* override_name:
|
|
* Name of the user-specified clocksource.
|
|
*/
|
|
static struct clocksource *curr_clocksource = &clocksource_jiffies;
|
|
static struct clocksource *next_clocksource;
|
|
static struct clocksource *clocksource_override;
|
|
static LIST_HEAD(clocksource_list);
|
|
static DEFINE_SPINLOCK(clocksource_lock);
|
|
static char override_name[32];
|
|
static int finished_booting;
|
|
|
|
/* clocksource_done_booting - Called near the end of core bootup
|
|
*
|
|
* Hack to avoid lots of clocksource churn at boot time.
|
|
* We use fs_initcall because we want this to start before
|
|
* device_initcall but after subsys_initcall.
|
|
*/
|
|
static int __init clocksource_done_booting(void)
|
|
{
|
|
finished_booting = 1;
|
|
return 0;
|
|
}
|
|
fs_initcall(clocksource_done_booting);
|
|
|
|
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
|
|
static LIST_HEAD(watchdog_list);
|
|
static struct clocksource *watchdog;
|
|
static struct timer_list watchdog_timer;
|
|
static DEFINE_SPINLOCK(watchdog_lock);
|
|
static cycle_t watchdog_last;
|
|
static unsigned long watchdog_resumed;
|
|
|
|
/*
|
|
* Interval: 0.5sec Threshold: 0.0625s
|
|
*/
|
|
#define WATCHDOG_INTERVAL (HZ >> 1)
|
|
#define WATCHDOG_THRESHOLD (NSEC_PER_SEC >> 4)
|
|
|
|
static void clocksource_ratewd(struct clocksource *cs, int64_t delta)
|
|
{
|
|
if (delta > -WATCHDOG_THRESHOLD && delta < WATCHDOG_THRESHOLD)
|
|
return;
|
|
|
|
printk(KERN_WARNING "Clocksource %s unstable (delta = %Ld ns)\n",
|
|
cs->name, delta);
|
|
cs->flags &= ~(CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_WATCHDOG);
|
|
clocksource_change_rating(cs, 0);
|
|
cs->flags &= ~CLOCK_SOURCE_WATCHDOG;
|
|
list_del(&cs->wd_list);
|
|
}
|
|
|
|
static void clocksource_watchdog(unsigned long data)
|
|
{
|
|
struct clocksource *cs, *tmp;
|
|
cycle_t csnow, wdnow;
|
|
int64_t wd_nsec, cs_nsec;
|
|
int resumed;
|
|
|
|
spin_lock(&watchdog_lock);
|
|
|
|
resumed = test_and_clear_bit(0, &watchdog_resumed);
|
|
|
|
wdnow = watchdog->read();
|
|
wd_nsec = cyc2ns(watchdog, (wdnow - watchdog_last) & watchdog->mask);
|
|
watchdog_last = wdnow;
|
|
|
|
list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list) {
|
|
csnow = cs->read();
|
|
|
|
if (unlikely(resumed)) {
|
|
cs->wd_last = csnow;
|
|
continue;
|
|
}
|
|
|
|
/* Initialized ? */
|
|
if (!(cs->flags & CLOCK_SOURCE_WATCHDOG)) {
|
|
if ((cs->flags & CLOCK_SOURCE_IS_CONTINUOUS) &&
|
|
(watchdog->flags & CLOCK_SOURCE_IS_CONTINUOUS)) {
|
|
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
|
|
/*
|
|
* We just marked the clocksource as
|
|
* highres-capable, notify the rest of the
|
|
* system as well so that we transition
|
|
* into high-res mode:
|
|
*/
|
|
tick_clock_notify();
|
|
}
|
|
cs->flags |= CLOCK_SOURCE_WATCHDOG;
|
|
cs->wd_last = csnow;
|
|
} else {
|
|
cs_nsec = cyc2ns(cs, (csnow - cs->wd_last) & cs->mask);
|
|
cs->wd_last = csnow;
|
|
/* Check the delta. Might remove from the list ! */
|
|
clocksource_ratewd(cs, cs_nsec - wd_nsec);
|
|
}
|
|
}
|
|
|
|
if (!list_empty(&watchdog_list)) {
|
|
__mod_timer(&watchdog_timer,
|
|
watchdog_timer.expires + WATCHDOG_INTERVAL);
|
|
}
|
|
spin_unlock(&watchdog_lock);
|
|
}
|
|
static void clocksource_resume_watchdog(void)
|
|
{
|
|
set_bit(0, &watchdog_resumed);
|
|
}
|
|
|
|
static void clocksource_check_watchdog(struct clocksource *cs)
|
|
{
|
|
struct clocksource *cse;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&watchdog_lock, flags);
|
|
if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
|
|
int started = !list_empty(&watchdog_list);
|
|
|
|
list_add(&cs->wd_list, &watchdog_list);
|
|
if (!started && watchdog) {
|
|
watchdog_last = watchdog->read();
|
|
watchdog_timer.expires = jiffies + WATCHDOG_INTERVAL;
|
|
add_timer(&watchdog_timer);
|
|
}
|
|
} else {
|
|
if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
|
|
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
|
|
|
|
if (!watchdog || cs->rating > watchdog->rating) {
|
|
if (watchdog)
|
|
del_timer(&watchdog_timer);
|
|
watchdog = cs;
|
|
init_timer(&watchdog_timer);
|
|
watchdog_timer.function = clocksource_watchdog;
|
|
|
|
/* Reset watchdog cycles */
|
|
list_for_each_entry(cse, &watchdog_list, wd_list)
|
|
cse->flags &= ~CLOCK_SOURCE_WATCHDOG;
|
|
/* Start if list is not empty */
|
|
if (!list_empty(&watchdog_list)) {
|
|
watchdog_last = watchdog->read();
|
|
watchdog_timer.expires =
|
|
jiffies + WATCHDOG_INTERVAL;
|
|
add_timer(&watchdog_timer);
|
|
}
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&watchdog_lock, flags);
|
|
}
|
|
#else
|
|
static void clocksource_check_watchdog(struct clocksource *cs)
|
|
{
|
|
if (cs->flags & CLOCK_SOURCE_IS_CONTINUOUS)
|
|
cs->flags |= CLOCK_SOURCE_VALID_FOR_HRES;
|
|
}
|
|
|
|
static inline void clocksource_resume_watchdog(void) { }
|
|
#endif
|
|
|
|
/**
|
|
* clocksource_resume - resume the clocksource(s)
|
|
*/
|
|
void clocksource_resume(void)
|
|
{
|
|
struct clocksource *cs;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&clocksource_lock, flags);
|
|
|
|
list_for_each_entry(cs, &clocksource_list, list) {
|
|
if (cs->resume)
|
|
cs->resume();
|
|
}
|
|
|
|
clocksource_resume_watchdog();
|
|
|
|
spin_unlock_irqrestore(&clocksource_lock, flags);
|
|
}
|
|
|
|
/**
|
|
* clocksource_get_next - Returns the selected clocksource
|
|
*
|
|
*/
|
|
struct clocksource *clocksource_get_next(void)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&clocksource_lock, flags);
|
|
if (next_clocksource && finished_booting) {
|
|
curr_clocksource = next_clocksource;
|
|
next_clocksource = NULL;
|
|
}
|
|
spin_unlock_irqrestore(&clocksource_lock, flags);
|
|
|
|
return curr_clocksource;
|
|
}
|
|
|
|
/**
|
|
* select_clocksource - Selects the best registered clocksource.
|
|
*
|
|
* Private function. Must hold clocksource_lock when called.
|
|
*
|
|
* Select the clocksource with the best rating, or the clocksource,
|
|
* which is selected by userspace override.
|
|
*/
|
|
static struct clocksource *select_clocksource(void)
|
|
{
|
|
struct clocksource *next;
|
|
|
|
if (list_empty(&clocksource_list))
|
|
return NULL;
|
|
|
|
if (clocksource_override)
|
|
next = clocksource_override;
|
|
else
|
|
next = list_entry(clocksource_list.next, struct clocksource,
|
|
list);
|
|
|
|
if (next == curr_clocksource)
|
|
return NULL;
|
|
|
|
return next;
|
|
}
|
|
|
|
/*
|
|
* Enqueue the clocksource sorted by rating
|
|
*/
|
|
static int clocksource_enqueue(struct clocksource *c)
|
|
{
|
|
struct list_head *tmp, *entry = &clocksource_list;
|
|
|
|
list_for_each(tmp, &clocksource_list) {
|
|
struct clocksource *cs;
|
|
|
|
cs = list_entry(tmp, struct clocksource, list);
|
|
if (cs == c)
|
|
return -EBUSY;
|
|
/* Keep track of the place, where to insert */
|
|
if (cs->rating >= c->rating)
|
|
entry = tmp;
|
|
}
|
|
list_add(&c->list, entry);
|
|
|
|
if (strlen(c->name) == strlen(override_name) &&
|
|
!strcmp(c->name, override_name))
|
|
clocksource_override = c;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* clocksource_register - Used to install new clocksources
|
|
* @t: clocksource to be registered
|
|
*
|
|
* Returns -EBUSY if registration fails, zero otherwise.
|
|
*/
|
|
int clocksource_register(struct clocksource *c)
|
|
{
|
|
unsigned long flags;
|
|
int ret;
|
|
|
|
spin_lock_irqsave(&clocksource_lock, flags);
|
|
ret = clocksource_enqueue(c);
|
|
if (!ret)
|
|
next_clocksource = select_clocksource();
|
|
spin_unlock_irqrestore(&clocksource_lock, flags);
|
|
if (!ret)
|
|
clocksource_check_watchdog(c);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(clocksource_register);
|
|
|
|
/**
|
|
* clocksource_change_rating - Change the rating of a registered clocksource
|
|
*
|
|
*/
|
|
void clocksource_change_rating(struct clocksource *cs, int rating)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&clocksource_lock, flags);
|
|
list_del(&cs->list);
|
|
cs->rating = rating;
|
|
clocksource_enqueue(cs);
|
|
next_clocksource = select_clocksource();
|
|
spin_unlock_irqrestore(&clocksource_lock, flags);
|
|
}
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
/**
|
|
* sysfs_show_current_clocksources - sysfs interface for current clocksource
|
|
* @dev: unused
|
|
* @buf: char buffer to be filled with clocksource list
|
|
*
|
|
* Provides sysfs interface for listing current clocksource.
|
|
*/
|
|
static ssize_t
|
|
sysfs_show_current_clocksources(struct sys_device *dev, char *buf)
|
|
{
|
|
char *curr = buf;
|
|
|
|
spin_lock_irq(&clocksource_lock);
|
|
curr += sprintf(curr, "%s ", curr_clocksource->name);
|
|
spin_unlock_irq(&clocksource_lock);
|
|
|
|
curr += sprintf(curr, "\n");
|
|
|
|
return curr - buf;
|
|
}
|
|
|
|
/**
|
|
* sysfs_override_clocksource - interface for manually overriding clocksource
|
|
* @dev: unused
|
|
* @buf: name of override clocksource
|
|
* @count: length of buffer
|
|
*
|
|
* Takes input from sysfs interface for manually overriding the default
|
|
* clocksource selction.
|
|
*/
|
|
static ssize_t sysfs_override_clocksource(struct sys_device *dev,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct clocksource *ovr = NULL;
|
|
size_t ret = count;
|
|
int len;
|
|
|
|
/* strings from sysfs write are not 0 terminated! */
|
|
if (count >= sizeof(override_name))
|
|
return -EINVAL;
|
|
|
|
/* strip of \n: */
|
|
if (buf[count-1] == '\n')
|
|
count--;
|
|
|
|
spin_lock_irq(&clocksource_lock);
|
|
|
|
if (count > 0)
|
|
memcpy(override_name, buf, count);
|
|
override_name[count] = 0;
|
|
|
|
len = strlen(override_name);
|
|
if (len) {
|
|
struct clocksource *cs;
|
|
|
|
ovr = clocksource_override;
|
|
/* try to select it: */
|
|
list_for_each_entry(cs, &clocksource_list, list) {
|
|
if (strlen(cs->name) == len &&
|
|
!strcmp(cs->name, override_name))
|
|
ovr = cs;
|
|
}
|
|
}
|
|
|
|
/* Reselect, when the override name has changed */
|
|
if (ovr != clocksource_override) {
|
|
clocksource_override = ovr;
|
|
next_clocksource = select_clocksource();
|
|
}
|
|
|
|
spin_unlock_irq(&clocksource_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* sysfs_show_available_clocksources - sysfs interface for listing clocksource
|
|
* @dev: unused
|
|
* @buf: char buffer to be filled with clocksource list
|
|
*
|
|
* Provides sysfs interface for listing registered clocksources
|
|
*/
|
|
static ssize_t
|
|
sysfs_show_available_clocksources(struct sys_device *dev, char *buf)
|
|
{
|
|
struct clocksource *src;
|
|
char *curr = buf;
|
|
|
|
spin_lock_irq(&clocksource_lock);
|
|
list_for_each_entry(src, &clocksource_list, list) {
|
|
curr += sprintf(curr, "%s ", src->name);
|
|
}
|
|
spin_unlock_irq(&clocksource_lock);
|
|
|
|
curr += sprintf(curr, "\n");
|
|
|
|
return curr - buf;
|
|
}
|
|
|
|
/*
|
|
* Sysfs setup bits:
|
|
*/
|
|
static SYSDEV_ATTR(current_clocksource, 0600, sysfs_show_current_clocksources,
|
|
sysfs_override_clocksource);
|
|
|
|
static SYSDEV_ATTR(available_clocksource, 0600,
|
|
sysfs_show_available_clocksources, NULL);
|
|
|
|
static struct sysdev_class clocksource_sysclass = {
|
|
.name = "clocksource",
|
|
};
|
|
|
|
static struct sys_device device_clocksource = {
|
|
.id = 0,
|
|
.cls = &clocksource_sysclass,
|
|
};
|
|
|
|
static int __init init_clocksource_sysfs(void)
|
|
{
|
|
int error = sysdev_class_register(&clocksource_sysclass);
|
|
|
|
if (!error)
|
|
error = sysdev_register(&device_clocksource);
|
|
if (!error)
|
|
error = sysdev_create_file(
|
|
&device_clocksource,
|
|
&attr_current_clocksource);
|
|
if (!error)
|
|
error = sysdev_create_file(
|
|
&device_clocksource,
|
|
&attr_available_clocksource);
|
|
return error;
|
|
}
|
|
|
|
device_initcall(init_clocksource_sysfs);
|
|
#endif /* CONFIG_SYSFS */
|
|
|
|
/**
|
|
* boot_override_clocksource - boot clock override
|
|
* @str: override name
|
|
*
|
|
* Takes a clocksource= boot argument and uses it
|
|
* as the clocksource override name.
|
|
*/
|
|
static int __init boot_override_clocksource(char* str)
|
|
{
|
|
unsigned long flags;
|
|
spin_lock_irqsave(&clocksource_lock, flags);
|
|
if (str)
|
|
strlcpy(override_name, str, sizeof(override_name));
|
|
spin_unlock_irqrestore(&clocksource_lock, flags);
|
|
return 1;
|
|
}
|
|
|
|
__setup("clocksource=", boot_override_clocksource);
|
|
|
|
/**
|
|
* boot_override_clock - Compatibility layer for deprecated boot option
|
|
* @str: override name
|
|
*
|
|
* DEPRECATED! Takes a clock= boot argument and uses it
|
|
* as the clocksource override name
|
|
*/
|
|
static int __init boot_override_clock(char* str)
|
|
{
|
|
if (!strcmp(str, "pmtmr")) {
|
|
printk("Warning: clock=pmtmr is deprecated. "
|
|
"Use clocksource=acpi_pm.\n");
|
|
return boot_override_clocksource("acpi_pm");
|
|
}
|
|
printk("Warning! clock= boot option is deprecated. "
|
|
"Use clocksource=xyz\n");
|
|
return boot_override_clocksource(str);
|
|
}
|
|
|
|
__setup("clock=", boot_override_clock);
|