Commit 7e6628e4 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'timers-clockevents-for-linus' of...

Merge branch 'timers-clockevents-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-clockevents-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: hpet: Cleanup the clockevents init and register code
  x86: Convert PIT to clockevents_config_and_register()
  clockevents: Provide interface to reconfigure an active clock event device
  clockevents: Provide combined configure and register function
  clockevents: Restructure clock_event_device members
  clocksource: Get rid of the hardcoded 5 seconds sleep time limit
  clocksource: Restructure clocksource struct members
parents 0f1bdc18 ab0e08f1
......@@ -217,7 +217,7 @@ static void hpet_reserve_platform_timers(unsigned int id) { }
/*
* Common hpet info
*/
static unsigned long hpet_period;
static unsigned long hpet_freq;
static void hpet_legacy_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt);
......@@ -232,7 +232,6 @@ static struct clock_event_device hpet_clockevent = {
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_mode = hpet_legacy_set_mode,
.set_next_event = hpet_legacy_next_event,
.shift = 32,
.irq = 0,
.rating = 50,
};
......@@ -289,29 +288,13 @@ static void hpet_legacy_clockevent_register(void)
/* Start HPET legacy interrupts */
hpet_enable_legacy_int();
/*
* The mult factor is defined as (include/linux/clockchips.h)
* mult/2^shift = cyc/ns (in contrast to ns/cyc in clocksource.h)
* hpet_period is in units of femtoseconds (per cycle), so
* mult/2^shift = cyc/ns = 10^6/hpet_period
* mult = (10^6 * 2^shift)/hpet_period
* mult = (FSEC_PER_NSEC << hpet_clockevent.shift)/hpet_period
*/
hpet_clockevent.mult = div_sc((unsigned long) FSEC_PER_NSEC,
hpet_period, hpet_clockevent.shift);
/* Calculate the min / max delta */
hpet_clockevent.max_delta_ns = clockevent_delta2ns(0x7FFFFFFF,
&hpet_clockevent);
/* Setup minimum reprogramming delta. */
hpet_clockevent.min_delta_ns = clockevent_delta2ns(HPET_MIN_PROG_DELTA,
&hpet_clockevent);
/*
* Start hpet with the boot cpu mask and make it
* global after the IO_APIC has been initialized.
*/
hpet_clockevent.cpumask = cpumask_of(smp_processor_id());
clockevents_register_device(&hpet_clockevent);
clockevents_config_and_register(&hpet_clockevent, hpet_freq,
HPET_MIN_PROG_DELTA, 0x7FFFFFFF);
global_clock_event = &hpet_clockevent;
printk(KERN_DEBUG "hpet clockevent registered\n");
}
......@@ -549,7 +532,6 @@ static int hpet_setup_irq(struct hpet_dev *dev)
static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu)
{
struct clock_event_device *evt = &hdev->evt;
uint64_t hpet_freq;
WARN_ON(cpu != smp_processor_id());
if (!(hdev->flags & HPET_DEV_VALID))
......@@ -571,24 +553,10 @@ static void init_one_hpet_msi_clockevent(struct hpet_dev *hdev, int cpu)
evt->set_mode = hpet_msi_set_mode;
evt->set_next_event = hpet_msi_next_event;
evt->shift = 32;
/*
* The period is a femto seconds value. We need to calculate the
* scaled math multiplication factor for nanosecond to hpet tick
* conversion.
*/
hpet_freq = FSEC_PER_SEC;
do_div(hpet_freq, hpet_period);
evt->mult = div_sc((unsigned long) hpet_freq,
NSEC_PER_SEC, evt->shift);
/* Calculate the max delta */
evt->max_delta_ns = clockevent_delta2ns(0x7FFFFFFF, evt);
/* 5 usec minimum reprogramming delta. */
evt->min_delta_ns = 5000;
evt->cpumask = cpumask_of(hdev->cpu);
clockevents_register_device(evt);
clockevents_config_and_register(evt, hpet_freq, HPET_MIN_PROG_DELTA,
0x7FFFFFFF);
}
#ifdef CONFIG_HPET
......@@ -792,7 +760,6 @@ static struct clocksource clocksource_hpet = {
static int hpet_clocksource_register(void)
{
u64 start, now;
u64 hpet_freq;
cycle_t t1;
/* Start the counter */
......@@ -819,24 +786,7 @@ static int hpet_clocksource_register(void)
return -ENODEV;
}
/*
* The definition of mult is (include/linux/clocksource.h)
* mult/2^shift = ns/cyc and hpet_period is in units of fsec/cyc
* so we first need to convert hpet_period to ns/cyc units:
* mult/2^shift = ns/cyc = hpet_period/10^6
* mult = (hpet_period * 2^shift)/10^6
* mult = (hpet_period << shift)/FSEC_PER_NSEC
*/
/* Need to convert hpet_period (fsec/cyc) to cyc/sec:
*
* cyc/sec = FSEC_PER_SEC/hpet_period(fsec/cyc)
* cyc/sec = (FSEC_PER_NSEC * NSEC_PER_SEC)/hpet_period
*/
hpet_freq = FSEC_PER_SEC;
do_div(hpet_freq, hpet_period);
clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq);
return 0;
}
......@@ -845,7 +795,9 @@ static int hpet_clocksource_register(void)
*/
int __init hpet_enable(void)
{
unsigned long hpet_period;
unsigned int id;
u64 freq;
int i;
if (!is_hpet_capable())
......@@ -883,6 +835,14 @@ int __init hpet_enable(void)
if (hpet_period < HPET_MIN_PERIOD || hpet_period > HPET_MAX_PERIOD)
goto out_nohpet;
/*
* The period is a femto seconds value. Convert it to a
* frequency.
*/
freq = FSEC_PER_SEC;
do_div(freq, hpet_period);
hpet_freq = freq;
/*
* Read the HPET ID register to retrieve the IRQ routing
* information and the number of channels
......
......@@ -93,7 +93,6 @@ static struct clock_event_device pit_ce = {
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.set_mode = init_pit_timer,
.set_next_event = pit_next_event,
.shift = 32,
.irq = 0,
};
......@@ -108,11 +107,8 @@ void __init setup_pit_timer(void)
* IO_APIC has been initialized.
*/
pit_ce.cpumask = cpumask_of(smp_processor_id());
pit_ce.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, pit_ce.shift);
pit_ce.max_delta_ns = clockevent_delta2ns(0x7FFF, &pit_ce);
pit_ce.min_delta_ns = clockevent_delta2ns(0xF, &pit_ce);
clockevents_register_device(&pit_ce);
clockevents_config_and_register(&pit_ce, CLOCK_TICK_RATE, 0xF, 0x7FFF);
global_clock_event = &pit_ce;
}
......
......@@ -56,46 +56,52 @@ enum clock_event_nofitiers {
/**
* struct clock_event_device - clock event device descriptor
* @name: ptr to clock event name
* @features: features
* @event_handler: Assigned by the framework to be called by the low
* level handler of the event source
* @set_next_event: set next event function
* @next_event: local storage for the next event in oneshot mode
* @max_delta_ns: maximum delta value in ns
* @min_delta_ns: minimum delta value in ns
* @mult: nanosecond to cycles multiplier
* @shift: nanoseconds to cycles divisor (power of two)
* @mode: operating mode assigned by the management code
* @features: features
* @retries: number of forced programming retries
* @set_mode: set mode function
* @broadcast: function to broadcast events
* @min_delta_ticks: minimum delta value in ticks stored for reconfiguration
* @max_delta_ticks: maximum delta value in ticks stored for reconfiguration
* @name: ptr to clock event name
* @rating: variable to rate clock event devices
* @irq: IRQ number (only for non CPU local devices)
* @cpumask: cpumask to indicate for which CPUs this device works
* @set_next_event: set next event function
* @set_mode: set mode function
* @event_handler: Assigned by the framework to be called by the low
* level handler of the event source
* @broadcast: function to broadcast events
* @list: list head for the management code
* @mode: operating mode assigned by the management code
* @next_event: local storage for the next event in oneshot mode
* @retries: number of forced programming retries
*/
struct clock_event_device {
const char *name;
unsigned int features;
void (*event_handler)(struct clock_event_device *);
int (*set_next_event)(unsigned long evt,
struct clock_event_device *);
ktime_t next_event;
u64 max_delta_ns;
u64 min_delta_ns;
u32 mult;
u32 shift;
enum clock_event_mode mode;
unsigned int features;
unsigned long retries;
void (*broadcast)(const struct cpumask *mask);
void (*set_mode)(enum clock_event_mode mode,
struct clock_event_device *);
unsigned long min_delta_ticks;
unsigned long max_delta_ticks;
const char *name;
int rating;
int irq;
const struct cpumask *cpumask;
int (*set_next_event)(unsigned long evt,
struct clock_event_device *);
void (*set_mode)(enum clock_event_mode mode,
struct clock_event_device *);
void (*event_handler)(struct clock_event_device *);
void (*broadcast)(const struct cpumask *mask);
struct list_head list;
enum clock_event_mode mode;
ktime_t next_event;
unsigned long retries;
};
} ____cacheline_aligned;
/*
* Calculate a multiplication factor for scaled math, which is used to convert
......@@ -122,6 +128,12 @@ extern u64 clockevent_delta2ns(unsigned long latch,
struct clock_event_device *evt);
extern void clockevents_register_device(struct clock_event_device *dev);
extern void clockevents_config_and_register(struct clock_event_device *dev,
u32 freq, unsigned long min_delta,
unsigned long max_delta);
extern int clockevents_update_freq(struct clock_event_device *ce, u32 freq);
extern void clockevents_exchange_device(struct clock_event_device *old,
struct clock_event_device *new);
extern void clockevents_set_mode(struct clock_event_device *dev,
......
......@@ -159,42 +159,38 @@ extern u64 timecounter_cyc2time(struct timecounter *tc,
*/
struct clocksource {
/*
* First part of structure is read mostly
* Hotpath data, fits in a single cache line when the
* clocksource itself is cacheline aligned.
*/
const char *name;
struct list_head list;
int rating;
cycle_t (*read)(struct clocksource *cs);
int (*enable)(struct clocksource *cs);
void (*disable)(struct clocksource *cs);
cycle_t cycle_last;
cycle_t mask;
u32 mult;
u32 shift;
u64 max_idle_ns;
unsigned long flags;
cycle_t (*vread)(void);
void (*suspend)(struct clocksource *cs);
void (*resume)(struct clocksource *cs);
#ifdef CONFIG_IA64
void *fsys_mmio; /* used by fsyscall asm code */
#define CLKSRC_FSYS_MMIO_SET(mmio, addr) ((mmio) = (addr))
#else
#define CLKSRC_FSYS_MMIO_SET(mmio, addr) do { } while (0)
#endif
/*
* Second part is written at each timer interrupt
* Keep it in a different cache line to dirty no
* more than one cache line.
*/
cycle_t cycle_last ____cacheline_aligned_in_smp;
const char *name;
struct list_head list;
int rating;
cycle_t (*vread)(void);
int (*enable)(struct clocksource *cs);
void (*disable)(struct clocksource *cs);
unsigned long flags;
void (*suspend)(struct clocksource *cs);
void (*resume)(struct clocksource *cs);
#ifdef CONFIG_CLOCKSOURCE_WATCHDOG
/* Watchdog related data, used by the framework */
struct list_head wd_list;
cycle_t wd_last;
#endif
};
} ____cacheline_aligned;
/*
* Clock source flags bits::
......
......@@ -194,6 +194,70 @@ void clockevents_register_device(struct clock_event_device *dev)
}
EXPORT_SYMBOL_GPL(clockevents_register_device);
static void clockevents_config(struct clock_event_device *dev,
u32 freq)
{
unsigned long sec;
if (!(dev->features & CLOCK_EVT_FEAT_ONESHOT))
return;
/*
* Calculate the maximum number of seconds we can sleep. Limit
* to 10 minutes for hardware which can program more than
* 32bit ticks so we still get reasonable conversion values.
*/
sec = dev->max_delta_ticks;
do_div(sec, freq);
if (!sec)
sec = 1;
else if (sec > 600 && dev->max_delta_ticks > UINT_MAX)
sec = 600;
clockevents_calc_mult_shift(dev, freq, sec);
dev->min_delta_ns = clockevent_delta2ns(dev->min_delta_ticks, dev);
dev->max_delta_ns = clockevent_delta2ns(dev->max_delta_ticks, dev);
}
/**
* clockevents_config_and_register - Configure and register a clock event device
* @dev: device to register
* @freq: The clock frequency
* @min_delta: The minimum clock ticks to program in oneshot mode
* @max_delta: The maximum clock ticks to program in oneshot mode
*
* min/max_delta can be 0 for devices which do not support oneshot mode.
*/
void clockevents_config_and_register(struct clock_event_device *dev,
u32 freq, unsigned long min_delta,
unsigned long max_delta)
{
dev->min_delta_ticks = min_delta;
dev->max_delta_ticks = max_delta;
clockevents_config(dev, freq);
clockevents_register_device(dev);
}
/**
* clockevents_update_freq - Update frequency and reprogram a clock event device.
* @dev: device to modify
* @freq: new device frequency
*
* Reconfigure and reprogram a clock event device in oneshot
* mode. Must be called on the cpu for which the device delivers per
* cpu timer events with interrupts disabled! Returns 0 on success,
* -ETIME when the event is in the past.
*/
int clockevents_update_freq(struct clock_event_device *dev, u32 freq)
{
clockevents_config(dev, freq);
if (dev->mode != CLOCK_EVT_MODE_ONESHOT)
return 0;
return clockevents_program_event(dev, dev->next_event, ktime_get());
}
/*
* Noop handler when we shut down an event device
*/
......
......@@ -626,19 +626,6 @@ static void clocksource_enqueue(struct clocksource *cs)
list_add(&cs->list, entry);
}
/*
* Maximum time we expect to go between ticks. This includes idle
* tickless time. It provides the trade off between selecting a
* mult/shift pair that is very precise but can only handle a short
* period of time, vs. a mult/shift pair that can handle long periods
* of time but isn't as precise.
*
* This is a subsystem constant, and actual hardware limitations
* may override it (ie: clocksources that wrap every 3 seconds).
*/
#define MAX_UPDATE_LENGTH 5 /* Seconds */
/**
* __clocksource_updatefreq_scale - Used update clocksource with new freq
* @t: clocksource to be registered
......@@ -652,15 +639,28 @@ static void clocksource_enqueue(struct clocksource *cs)
*/
void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq)
{
unsigned long sec;
/*
* Ideally we want to use some of the limits used in
* clocksource_max_deferment, to provide a more informed
* MAX_UPDATE_LENGTH. But for now this just gets the
* register interface working properly.
* Calc the maximum number of seconds which we can run before
* wrapping around. For clocksources which have a mask > 32bit
* we need to limit the max sleep time to have a good
* conversion precision. 10 minutes is still a reasonable
* amount. That results in a shift value of 24 for a
* clocksource with mask >= 40bit and f >= 4GHz. That maps to
* ~ 0.06ppm granularity for NTP. We apply the same 12.5%
* margin as we do in clocksource_max_deferment()
*/
sec = (cs->mask - (cs->mask >> 5));
do_div(sec, freq);
do_div(sec, scale);
if (!sec)
sec = 1;
else if (sec > 600 && cs->mask > UINT_MAX)
sec = 600;
clocks_calc_mult_shift(&cs->mult, &cs->shift, freq,
NSEC_PER_SEC/scale,
MAX_UPDATE_LENGTH*scale);
NSEC_PER_SEC / scale, sec * scale);
cs->max_idle_ns = clocksource_max_deferment(cs);
}
EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale);
......
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