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time: move the timecounter/cyclecounter code into its own file.

Browse Source 
The timecounter code has almost nothing to do with the clocksource
code. Let it live in its own file. This will help isolate the
timecounter users from the clocksource users in the source tree.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Richard Cochran 2014-12-21 19:46:56 +01:00 committed by David S. Miller
parent 2c90331cf5
commit 74d23cc704
16 changed files with 231 additions and 187 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/ethernet/amd/xgbe/xgbe.h
View File

@ -124,7 +124,7 @@
#include <linux/if_vlan.h>
#include <linux/bitops.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/clocksource.h>
#include <linux/timecounter.h>
#include <linux/net_tstamp.h>
#include <net/dcbnl.h>

2
drivers/net/ethernet/broadcom/bnx2x/bnx2x.h
View File

@ -22,7 +22,7 @@
#include <linux/ptp_clock_kernel.h>
#include <linux/net_tstamp.h>
#include <linux/clocksource.h>
#include <linux/timecounter.h>
/* compilation time flags */

1
drivers/net/ethernet/freescale/fec.h
View File

@ -16,6 +16,7 @@
#include <linux/clocksource.h>
#include <linux/net_tstamp.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/timecounter.h>
#if defined(CONFIG_M523x) || defined(CONFIG_M527x) || defined(CONFIG_M528x) || \
defined(CONFIG_M520x) || defined(CONFIG_M532x) || \

2
drivers/net/ethernet/intel/e1000e/e1000.h
View File

@ -34,7 +34,7 @@
#include <linux/pci-aspm.h>
#include <linux/crc32.h>
#include <linux/if_vlan.h>
#include <linux/clocksource.h>
#include <linux/timecounter.h>
#include <linux/net_tstamp.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/ptp_classify.h>

2
drivers/net/ethernet/intel/igb/igb.h
View File

@ -29,7 +29,7 @@
#include "e1000_mac.h"
#include "e1000_82575.h"
#include <linux/clocksource.h>
#include <linux/timecounter.h>
#include <linux/net_tstamp.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/bitops.h>

2
drivers/net/ethernet/intel/ixgbe/ixgbe.h
View File

@ -38,7 +38,7 @@
#include <linux/if_vlan.h>
#include <linux/jiffies.h>
#include <linux/clocksource.h>
#include <linux/timecounter.h>
#include <linux/net_tstamp.h>
#include <linux/ptp_clock_kernel.h>

1
drivers/net/ethernet/ti/cpts.h
View File

@ -27,6 +27,7 @@
#include <linux/list.h>
#include <linux/ptp_clock_kernel.h>
#include <linux/skbuff.h>
#include <linux/timecounter.h>
struct cpsw_cpts {
u32 idver; /* Identification and version */

2
include/clocksource/arm_arch_timer.h
View File

@ -16,7 +16,7 @@
#ifndef __CLKSOURCE_ARM_ARCH_TIMER_H
#define __CLKSOURCE_ARM_ARCH_TIMER_H
#include <linux/clocksource.h>
#include <linux/timecounter.h>
#include <linux/types.h>
#define ARCH_TIMER_CTRL_ENABLE (1 << 0)

102
include/linux/clocksource.h
View File

@ -18,8 +18,6 @@
#include <asm/div64.h>
#include <asm/io.h>
/* clocksource cycle base type */
typedef u64 cycle_t;
struct clocksource;
struct module;
@ -27,106 +25,6 @@ struct module;
#include <asm/clocksource.h>
#endif
/**
* struct cyclecounter - hardware abstraction for a free running counter
* Provides completely state-free accessors to the underlying hardware.
* Depending on which hardware it reads, the cycle counter may wrap
* around quickly. Locking rules (if necessary) have to be defined
* by the implementor and user of specific instances of this API.
*
* @read: returns the current cycle value
* @mask: bitmask for two's complement
* subtraction of non 64 bit counters,
* see CLOCKSOURCE_MASK() helper macro
* @mult: cycle to nanosecond multiplier
* @shift: cycle to nanosecond divisor (power of two)
*/
struct cyclecounter {
cycle_t (*read)(const struct cyclecounter *cc);
cycle_t mask;
u32 mult;
u32 shift;
};
/**
* struct timecounter - layer above a %struct cyclecounter which counts nanoseconds
* Contains the state needed by timecounter_read() to detect
* cycle counter wrap around. Initialize with
* timecounter_init(). Also used to convert cycle counts into the
* corresponding nanosecond counts with timecounter_cyc2time(). Users
* of this code are responsible for initializing the underlying
* cycle counter hardware, locking issues and reading the time
* more often than the cycle counter wraps around. The nanosecond
* counter will only wrap around after ~585 years.
*
* @cc: the cycle counter used by this instance
* @cycle_last: most recent cycle counter value seen by
* timecounter_read()
* @nsec: continuously increasing count
*/
struct timecounter {
const struct cyclecounter *cc;
cycle_t cycle_last;
u64 nsec;
};
/**
* cyclecounter_cyc2ns - converts cycle counter cycles to nanoseconds
* @cc: Pointer to cycle counter.
* @cycles: Cycles
*
* XXX - This could use some mult_lxl_ll() asm optimization. Same code
* as in cyc2ns, but with unsigned result.
*/
static inline u64 cyclecounter_cyc2ns(const struct cyclecounter *cc,
cycle_t cycles)
{
u64 ret = (u64)cycles;
ret = (ret * cc->mult) >> cc->shift;
return ret;
}
/**
* timecounter_init - initialize a time counter
* @tc: Pointer to time counter which is to be initialized/reset
* @cc: A cycle counter, ready to be used.
* @start_tstamp: Arbitrary initial time stamp.
*
* After this call the current cycle register (roughly) corresponds to
* the initial time stamp. Every call to timecounter_read() increments
* the time stamp counter by the number of elapsed nanoseconds.
*/
extern void timecounter_init(struct timecounter *tc,
const struct cyclecounter *cc,
u64 start_tstamp);
/**
* timecounter_read - return nanoseconds elapsed since timecounter_init()
* plus the initial time stamp
* @tc: Pointer to time counter.
*
* In other words, keeps track of time since the same epoch as
* the function which generated the initial time stamp.
*/
extern u64 timecounter_read(struct timecounter *tc);
/**
* timecounter_cyc2time - convert a cycle counter to same
* time base as values returned by
* timecounter_read()
* @tc: Pointer to time counter.
* @cycle_tstamp: a value returned by tc->cc->read()
*
* Cycle counts that are converted correctly as long as they
* fall into the interval [-1/2 max cycle count, +1/2 max cycle count],
* with "max cycle count" == cs->mask+1.
*
* This allows conversion of cycle counter values which were generated
* in the past.
*/
extern u64 timecounter_cyc2time(struct timecounter *tc,
cycle_t cycle_tstamp);
/**
* struct clocksource - hardware abstraction for a free running counter
* Provides mostly state-free accessors to the underlying hardware.

2
include/linux/mlx4/device.h
View File

@ -42,7 +42,7 @@
#include <linux/atomic.h>
#include <linux/clocksource.h>
#include <linux/timecounter.h>
#define MAX_MSIX_P_PORT 17
#define MAX_MSIX 64

122
include/linux/timecounter.h Normal file
View File

@ -0,0 +1,122 @@
/*
* linux/include/linux/timecounter.h
*
* based on code that migrated away from
* linux/include/linux/clocksource.h
*
* 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.
*/
#ifndef _LINUX_TIMECOUNTER_H
#define _LINUX_TIMECOUNTER_H
#include <linux/types.h>
/**
* struct cyclecounter - hardware abstraction for a free running counter
* Provides completely state-free accessors to the underlying hardware.
* Depending on which hardware it reads, the cycle counter may wrap
* around quickly. Locking rules (if necessary) have to be defined
* by the implementor and user of specific instances of this API.
*
* @read: returns the current cycle value
* @mask: bitmask for two's complement
* subtraction of non 64 bit counters,
* see CLOCKSOURCE_MASK() helper macro
* @mult: cycle to nanosecond multiplier
* @shift: cycle to nanosecond divisor (power of two)
*/
struct cyclecounter {
cycle_t (*read)(const struct cyclecounter *cc);
cycle_t mask;
u32 mult;
u32 shift;
};
/**
* struct timecounter - layer above a %struct cyclecounter which counts nanoseconds
* Contains the state needed by timecounter_read() to detect
* cycle counter wrap around. Initialize with
* timecounter_init(). Also used to convert cycle counts into the
* corresponding nanosecond counts with timecounter_cyc2time(). Users
* of this code are responsible for initializing the underlying
* cycle counter hardware, locking issues and reading the time
* more often than the cycle counter wraps around. The nanosecond
* counter will only wrap around after ~585 years.
*
* @cc: the cycle counter used by this instance
* @cycle_last: most recent cycle counter value seen by
* timecounter_read()
* @nsec: continuously increasing count
*/
struct timecounter {
const struct cyclecounter *cc;
cycle_t cycle_last;
u64 nsec;
};
/**
* cyclecounter_cyc2ns - converts cycle counter cycles to nanoseconds
* @cc: Pointer to cycle counter.
* @cycles: Cycles
*
* XXX - This could use some mult_lxl_ll() asm optimization. Same code
* as in cyc2ns, but with unsigned result.
*/
static inline u64 cyclecounter_cyc2ns(const struct cyclecounter *cc,
cycle_t cycles)
{
u64 ret = (u64)cycles;
ret = (ret * cc->mult) >> cc->shift;
return ret;
}
/**
* timecounter_init - initialize a time counter
* @tc: Pointer to time counter which is to be initialized/reset
* @cc: A cycle counter, ready to be used.
* @start_tstamp: Arbitrary initial time stamp.
*
* After this call the current cycle register (roughly) corresponds to
* the initial time stamp. Every call to timecounter_read() increments
* the time stamp counter by the number of elapsed nanoseconds.
*/
extern void timecounter_init(struct timecounter *tc,
const struct cyclecounter *cc,
u64 start_tstamp);
/**
* timecounter_read - return nanoseconds elapsed since timecounter_init()
* plus the initial time stamp
* @tc: Pointer to time counter.
*
* In other words, keeps track of time since the same epoch as
* the function which generated the initial time stamp.
*/
extern u64 timecounter_read(struct timecounter *tc);
/**
* timecounter_cyc2time - convert a cycle counter to same
* time base as values returned by
* timecounter_read()
* @tc: Pointer to time counter.
* @cycle_tstamp: a value returned by tc->cc->read()
*
* Cycle counts that are converted correctly as long as they
* fall into the interval [-1/2 max cycle count, +1/2 max cycle count],
* with "max cycle count" == cs->mask+1.
*
* This allows conversion of cycle counter values which were generated
* in the past.
*/
extern u64 timecounter_cyc2time(struct timecounter *tc,
cycle_t cycle_tstamp);
#endif

3
include/linux/types.h
View File

@ -213,5 +213,8 @@ struct callback_head {
};
#define rcu_head callback_head
/* clocksource cycle base type */
typedef u64 cycle_t;
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_TYPES_H */

2
kernel/time/Makefile
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@ -1,6 +1,6 @@
obj-y += time.o timer.o hrtimer.o itimer.o posix-timers.o posix-cpu-timers.o
obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o
obj-y += timeconv.o posix-clock.o alarmtimer.o
obj-y += timeconv.o timecounter.o posix-clock.o alarmtimer.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD) += clockevents.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS) += tick-common.o

76
kernel/time/clocksource.c
View File

@ -34,82 +34,6 @@
#include "tick-internal.h"
#include "timekeeping_internal.h"
void timecounter_init(struct timecounter *tc,
const struct cyclecounter *cc,
u64 start_tstamp)
{
tc->cc = cc;
tc->cycle_last = cc->read(cc);
tc->nsec = start_tstamp;
}
EXPORT_SYMBOL_GPL(timecounter_init);
/**
* timecounter_read_delta - get nanoseconds since last call of this function
* @tc: Pointer to time counter
*
* When the underlying cycle counter runs over, this will be handled
* correctly as long as it does not run over more than once between
* calls.
*
* The first call to this function for a new time counter initializes
* the time tracking and returns an undefined result.
*/
static u64 timecounter_read_delta(struct timecounter *tc)
{
cycle_t cycle_now, cycle_delta;
u64 ns_offset;
/* read cycle counter: */
cycle_now = tc->cc->read(tc->cc);
/* calculate the delta since the last timecounter_read_delta(): */
cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask;
/* convert to nanoseconds: */
ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta);
/* update time stamp of timecounter_read_delta() call: */
tc->cycle_last = cycle_now;
return ns_offset;
}
u64 timecounter_read(struct timecounter *tc)
{
u64 nsec;
/* increment time by nanoseconds since last call */
nsec = timecounter_read_delta(tc);
nsec += tc->nsec;
tc->nsec = nsec;
return nsec;
}
EXPORT_SYMBOL_GPL(timecounter_read);
u64 timecounter_cyc2time(struct timecounter *tc,
cycle_t cycle_tstamp)
{
u64 cycle_delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask;
u64 nsec;
/*
* Instead of always treating cycle_tstamp as more recent
* than tc->cycle_last, detect when it is too far in the
* future and treat it as old time stamp instead.
*/
if (cycle_delta > tc->cc->mask / 2) {
cycle_delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask;
nsec = tc->nsec - cyclecounter_cyc2ns(tc->cc, cycle_delta);
} else {
nsec = cyclecounter_cyc2ns(tc->cc, cycle_delta) + tc->nsec;
}
return nsec;
}
EXPORT_SYMBOL_GPL(timecounter_cyc2time);
/**
* clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks
* @mult: pointer to mult variable

95
kernel/time/timecounter.c Normal file
View File

@ -0,0 +1,95 @@
/*
* linux/kernel/time/timecounter.c
*
* based on code that migrated away from
* linux/kernel/time/clocksource.c
*
* 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.
*/
#include <linux/export.h>
#include <linux/timecounter.h>
void timecounter_init(struct timecounter *tc,
const struct cyclecounter *cc,
u64 start_tstamp)
{
tc->cc = cc;
tc->cycle_last = cc->read(cc);
tc->nsec = start_tstamp;
}
EXPORT_SYMBOL_GPL(timecounter_init);
/**
* timecounter_read_delta - get nanoseconds since last call of this function
* @tc: Pointer to time counter
*
* When the underlying cycle counter runs over, this will be handled
* correctly as long as it does not run over more than once between
* calls.
*
* The first call to this function for a new time counter initializes
* the time tracking and returns an undefined result.
*/
static u64 timecounter_read_delta(struct timecounter *tc)
{
cycle_t cycle_now, cycle_delta;
u64 ns_offset;
/* read cycle counter: */
cycle_now = tc->cc->read(tc->cc);
/* calculate the delta since the last timecounter_read_delta(): */
cycle_delta = (cycle_now - tc->cycle_last) & tc->cc->mask;
/* convert to nanoseconds: */
ns_offset = cyclecounter_cyc2ns(tc->cc, cycle_delta);
/* update time stamp of timecounter_read_delta() call: */
tc->cycle_last = cycle_now;
return ns_offset;
}
u64 timecounter_read(struct timecounter *tc)
{
u64 nsec;
/* increment time by nanoseconds since last call */
nsec = timecounter_read_delta(tc);
nsec += tc->nsec;
tc->nsec = nsec;
return nsec;
}
EXPORT_SYMBOL_GPL(timecounter_read);
u64 timecounter_cyc2time(struct timecounter *tc,
cycle_t cycle_tstamp)
{
u64 cycle_delta = (cycle_tstamp - tc->cycle_last) & tc->cc->mask;
u64 nsec;
/*
* Instead of always treating cycle_tstamp as more recent
* than tc->cycle_last, detect when it is too far in the
* future and treat it as old time stamp instead.
*/
if (cycle_delta > tc->cc->mask / 2) {
cycle_delta = (tc->cycle_last - cycle_tstamp) & tc->cc->mask;
nsec = tc->nsec - cyclecounter_cyc2ns(tc->cc, cycle_delta);
} else {
nsec = cyclecounter_cyc2ns(tc->cc, cycle_delta) + tc->nsec;
}
return nsec;
}
EXPORT_SYMBOL_GPL(timecounter_cyc2time);

2
sound/pci/hda/hda_priv.h
View File

@ -15,7 +15,7 @@
#ifndef __SOUND_HDA_PRIV_H
#define __SOUND_HDA_PRIV_H
#include <linux/clocksource.h>
#include <linux/timecounter.h>
#include <sound/core.h>
#include <sound/pcm.h>