Problem with system time in lpc176x bsp
Joel Sherrill
joel at rtems.org
Mon Jan 11 19:40:11 UTC 2016
On Mon, Jan 11, 2016 at 1:25 PM, Marcos Díaz <
marcos.diaz at tallertechnologies.com> wrote:
> Well, we could still use the patch you sent with the protection in is
> pending, but I think this will break the BSPs I mentioned, since you
> changed timecounter functions signatures. Am I right?
>
>
Let's just fix it right. The timecounters are new so getting them right in
the first release with
them is important.
> On Mon, Jan 11, 2016 at 4:18 PM, Sebastian Huber <
> sebastian.huber at embedded-brains.de> wrote:
>
>> Hello,
>>
>> I already created a ticket which blocks the 4.11 release for this bug:
>>
>> https://devel.rtems.org/ticket/2502
>>
>> I sent a new version of the patch to one of your previous threads some
>> days ago:
>>
>> https://lists.rtems.org/pipermail/devel/2016-January/013289.html
>>
>> There is still a bug in it, since we must disable interrupts in the is
>> pending function, but the general approach should work.
>>
>> ----- Am 11. Jan 2016 um 20:05 schrieb Marcos Díaz
>> marcos.diaz at tallertechnologies.com:
>>
>> > I made a fast search:
>> > These BSPs use *rtems_timecounter_simple_downcounter*:
>> > arm/shared/armv7m
>> > m68k/mcf52235
>> > m68k/mcf5225x
>> > m68k/mcf5329
>> > m68k/uC5282
>> > powerpc/mpc55xxevb
>> > sparc/erc32
>> > sparc/leon2
>> > sparc/leon3
>> > sparc/shared
>> >
>> > These use *rtems_timecounter_simple_upcounter*:
>> > powerpc/mpc55xxevb
>> > arm/lpc22xx
>> >
>> > We should search a little more for the other changes but at least these
>> > BSPs will be affected. Maybe we should wait Sebastian's opinion, since
>> he
>> > suggested the change in timecounter's signatures.
>> >
>> > On Mon, Jan 11, 2016 at 3:44 PM, Joel Sherrill <joel at rtems.org> wrote:
>> >
>> >>
>> >>
>> >> On Mon, Jan 11, 2016 at 12:28 PM, Marcos Díaz <
>> >> marcos.diaz at tallertechnologies.com> wrote:
>> >>
>> >>> I will issue a ticket. But I noticed that in my patch I include
>> changes
>> >>> to common code that Sebastian suggested, and this will break any
>> other BSP
>> >>> that uses rtems timecounter simple downcounter or upcounter, since
>> these
>> >>> function's signatures changed. Should we update all BSPs? Or make
>> changes
>> >>> more locally to our BSP? Meanwhile please do not apply the patch I
>> sent.
>> >>>
>> >>>
>> >> I would prefer not to ship BSPs with bugs but fixing them comes with
>> risks.
>> >> So I would lean to the same fix on the master and 4.11 branch fixing it
>> >> where it needs to be fixed.
>> >>
>> >> What BSPs does this change impact?
>> >>
>> >> --joel
>> >>
>> >>
>> >>>
>> >>> On Mon, Jan 11, 2016 at 3:16 PM, Joel Sherrill <joel at rtems.org>
>> wrote:
>> >>>
>> >>>> At this point, a ticket is needed for anything applied to 4.11 that
>> is
>> >>>> not release
>> >>>> mechanics related.
>> >>>>
>> >>>> --joel
>> >>>>
>> >>>> On Mon, Jan 11, 2016 at 11:47 AM, Marcos Diaz <
>> >>>> marcos.diaz at tallertechnologies.com> wrote:
>> >>>>
>> >>>>> Hi Sebastian,
>> >>>>>
>> >>>>> we did some more testing and found out what's causing the problem.
>> >>>>> Based on what
>> >>>>> I posted at
>> >>>>> https://lists.rtems.org/pipermail/devel/2015-December/013235.html,
>> >>>>> the problem arises when the ticker interrupt occurs while a task is
>> >>>>> executing
>> >>>>> one of the instructions that make up the following line:
>> >>>>>
>> >>>>> is_count_pending = (systick->csr & ARMV7M_SYSTICK_CSR_COUNTFLAG) !=
>> 0;
>> >>>>>
>> >>>>> which compiling with -O3 are:
>> >>>>>
>> >>>>> ldr.w r3, [r9]
>> >>>>> ubfx r5, r3, #16, #1
>> >>>>> strb.w r5, [r8, #64]
>> >>>>>
>> >>>>> If the SysTick counts to 0 and the ldr executes before the interrupt
>> >>>>> occurs,
>> >>>>> R3 will have the CSR.COUNTFLAG bit set. Even though
>> _ARMV7M_TC_at_tick
>> >>>>> will
>> >>>>> clear the is_count_pending boolean, the task will still see it as
>> true.
>> >>>>>
>> >>>>> The solution we found is to simply disable interrupts while reading
>> >>>>> that flag.
>> >>>>> We also use a local variable inside _ARMV7M_TC_is_pending instead of
>> >>>>> directly
>> >>>>> returning the current value of the is_count_pending global, just in
>> >>>>> case.
>> >>>>>
>> >>>>> Here's the patch that fixes it; this applies to the 4.11 branch.
>> >>>>> Do we have to open a new thread for it to be applied to the
>> mainline,
>> >>>>> or will
>> >>>>> this suffice? Should we open a ticket for 4.11?
>> >>>>>
>> >>>>> ---
>> >>>>> .../arm/shared/armv7m/clock/armv7m-clock-config.c | 38
>> >>>>> +++++++++++++++-------
>> >>>>> c/src/lib/libbsp/shared/clockdrv_shell.h | 16 ++++++++-
>> >>>>> cpukit/rtems/src/clocktick.c | 6 +++-
>> >>>>> cpukit/sapi/include/rtems/timecounter.h | 35
>> >>>>> ++++++++++++++++----
>> >>>>> cpukit/score/include/rtems/score/timecounter.h | 37
>> >>>>> +++++++++++++++++++--
>> >>>>> cpukit/score/src/kern_tc.c | 16 ++++-----
>> >>>>> doc/bsp_howto/clock.t | 13 +++++++-
>> >>>>> 7 files changed, 130 insertions(+), 31 deletions(-)
>> >>>>>
>> >>>>> diff --git
>> >>>>> a/c/src/lib/libbsp/arm/shared/armv7m/clock/armv7m-clock-config.c
>> >>>>> b/c/src/lib/libbsp/arm/shared/armv7m/clock/armv7m-clock-config.c
>> >>>>> index e78684c..53bd7cf 100644
>> >>>>> --- a/c/src/lib/libbsp/arm/shared/armv7m/clock/armv7m-clock-config.c
>> >>>>> +++ b/c/src/lib/libbsp/arm/shared/armv7m/clock/armv7m-clock-config.c
>> >>>>> @@ -25,6 +25,8 @@ static void Clock_isr(void *arg);
>> >>>>>
>> >>>>> static rtems_timecounter_simple _ARMV7M_TC;
>> >>>>>
>> >>>>> +static bool is_count_pending = false;
>> >>>>> +
>> >>>>> static uint32_t _ARMV7M_TC_get(rtems_timecounter_simple *tc)
>> >>>>> {
>> >>>>> volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
>> >>>>> @@ -34,9 +36,20 @@ static uint32_t
>> >>>>> _ARMV7M_TC_get(rtems_timecounter_simple *tc)
>> >>>>>
>> >>>>> static bool _ARMV7M_TC_is_pending(rtems_timecounter_simple *tc)
>> >>>>> {
>> >>>>> - volatile ARMV7M_SCB *scb = _ARMV7M_SCB;
>> >>>>> + volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
>> >>>>> + ISR_lock_Context lock_context;
>> >>>>> +
>> >>>>> + _Timecounter_Acquire( &lock_context );
>> >>>>> + /* We use this bool since the hardware flag is reset each time
>> it is
>> >>>>> read. */
>> >>>>> + if (!is_count_pending)
>> >>>>> + {
>> >>>>> + is_count_pending = ((systick->csr &
>> ARMV7M_SYSTICK_CSR_COUNTFLAG)
>> >>>>> != 0 );
>> >>>>> + }
>> >>>>>
>> >>>>> - return ((scb->icsr & ARMV7M_SCB_ICSR_PENDSTSET) != 0);
>> >>>>> + const bool is_pending_local = is_count_pending;
>> >>>>> +
>> >>>>> + _Timecounter_Release( &lock_context );
>> >>>>> + return is_pending_local;
>> >>>>> }
>> >>>>>
>> >>>>> static uint32_t _ARMV7M_TC_get_timecount(struct timecounter *tc)
>> >>>>> @@ -48,19 +61,23 @@ static uint32_t _ARMV7M_TC_get_timecount(struct
>> >>>>> timecounter *tc)
>> >>>>> );
>> >>>>> }
>> >>>>>
>> >>>>> -static void _ARMV7M_TC_tick(void)
>> >>>>> -{
>> >>>>> - rtems_timecounter_simple_downcounter_tick(&_ARMV7M_TC,
>> >>>>> _ARMV7M_TC_get);
>> >>>>> -}
>> >>>>> -
>> >>>>> -static void _ARMV7M_Systick_at_tick(void)
>> >>>>> +static void _ARMV7M_TC_at_tick(rtems_timecounter_simple *tc)
>> >>>>> {
>> >>>>> volatile ARMV7M_Systick *systick = _ARMV7M_Systick;
>> >>>>> -
>> >>>>> + is_count_pending = false;
>> >>>>> /* Clear COUNTFLAG */
>> >>>>> systick->csr;
>> >>>>> }
>> >>>>>
>> >>>>> +static void _ARMV7M_TC_tick(void)
>> >>>>> +{
>> >>>>> + rtems_timecounter_simple_downcounter_tick(
>> >>>>> + &_ARMV7M_TC,
>> >>>>> + _ARMV7M_TC_get,
>> >>>>> + _ARMV7M_TC_at_tick
>> >>>>> + );
>> >>>>> +}
>> >>>>> +
>> >>>>> static void _ARMV7M_Systick_handler(void)
>> >>>>> {
>> >>>>> _ARMV7M_Interrupt_service_enter();
>> >>>>> @@ -111,9 +128,6 @@ static void _ARMV7M_Systick_cleanup(void)
>> >>>>>
>> >>>>> #define Clock_driver_timecounter_tick() _ARMV7M_TC_tick()
>> >>>>>
>> >>>>> -#define Clock_driver_support_at_tick() \
>> >>>>> - _ARMV7M_Systick_at_tick()
>> >>>>> -
>> >>>>> #define Clock_driver_support_initialize_hardware() \
>> >>>>> _ARMV7M_Systick_initialize()
>> >>>>>
>> >>>>> diff --git a/c/src/lib/libbsp/shared/clockdrv_shell.h
>> >>>>> b/c/src/lib/libbsp/shared/clockdrv_shell.h
>> >>>>> index d546fb8..96b962f 100644
>> >>>>> --- a/c/src/lib/libbsp/shared/clockdrv_shell.h
>> >>>>> +++ b/c/src/lib/libbsp/shared/clockdrv_shell.h
>> >>>>> @@ -44,6 +44,13 @@
>> >>>>> #define Clock_driver_support_find_timer()
>> >>>>> #endif
>> >>>>>
>> >>>>> +/**
>> >>>>> + * @brief Do nothing by default.
>> >>>>> + */
>> >>>>> +#ifndef Clock_driver_support_at_tick
>> >>>>> + #define Clock_driver_support_at_tick()
>> >>>>> +#endif
>> >>>>> +
>> >>>>> /*
>> >>>>> * A specialized clock driver may use for example
>> >>>>> rtems_timecounter_tick_simple()
>> >>>>> * instead of the default.
>> >>>>> @@ -108,7 +115,14 @@ rtems_isr Clock_isr(
>> >>>>> && _Thread_Executing->Start.entry_point
>> >>>>> == (Thread_Entry) rtems_configuration_get_idle_task()
>> >>>>> ) {
>> >>>>> - _Timecounter_Tick_simple(interval,
>> >>>>> (*tc->tc_get_timecount)(tc));
>> >>>>> + ISR_lock_Context lock_context;
>> >>>>> +
>> >>>>> + _Timecounter_Acquire(&lock_context);
>> >>>>> + _Timecounter_Tick_simple(
>> >>>>> + interval,
>> >>>>> + (*tc->tc_get_timecount)(tc),
>> >>>>> + &lock_context
>> >>>>> + );
>> >>>>> }
>> >>>>>
>> >>>>> Clock_driver_support_at_tick();
>> >>>>> diff --git a/cpukit/rtems/src/clocktick.c
>> b/cpukit/rtems/src/clocktick.c
>> >>>>> index e2cd35f..a6bf26d 100644
>> >>>>> --- a/cpukit/rtems/src/clocktick.c
>> >>>>> +++ b/cpukit/rtems/src/clocktick.c
>> >>>>> @@ -23,9 +23,13 @@
>> >>>>>
>> >>>>> rtems_status_code rtems_clock_tick( void )
>> >>>>> {
>> >>>>> + ISR_lock_Context lock_context;
>> >>>>> +
>> >>>>> + _Timecounter_Acquire( &lock_context );
>> >>>>> _Timecounter_Tick_simple(
>> >>>>> rtems_configuration_get_microseconds_per_tick(),
>> >>>>> - 0
>> >>>>> + 0,
>> >>>>> + &lock_context
>> >>>>> );
>> >>>>>
>> >>>>> return RTEMS_SUCCESSFUL;
>> >>>>> diff --git a/cpukit/sapi/include/rtems/timecounter.h
>> >>>>> b/cpukit/sapi/include/rtems/timecounter.h
>> >>>>> index 04bc534..06b3973 100644
>> >>>>> --- a/cpukit/sapi/include/rtems/timecounter.h
>> >>>>> +++ b/cpukit/sapi/include/rtems/timecounter.h
>> >>>>> @@ -94,6 +94,13 @@ typedef struct {
>> >>>>> } rtems_timecounter_simple;
>> >>>>>
>> >>>>> /**
>> >>>>> + * @brief At tick handling done under protection of the timecounter
>> >>>>> lock.
>> >>>>> + */
>> >>>>> +typedef uint32_t rtems_timecounter_simple_at_tick(
>> >>>>> + rtems_timecounter_simple *tc
>> >>>>> +);
>> >>>>> +
>> >>>>> +/**
>> >>>>> * @brief Returns the current value of a simple timecounter.
>> >>>>> */
>> >>>>> typedef uint32_t rtems_timecounter_simple_get(
>> >>>>> @@ -199,20 +206,28 @@ RTEMS_INLINE_ROUTINE uint32_t
>> >>>>> rtems_timecounter_simple_scale(
>> >>>>> *
>> >>>>> * @param[in] tc The simple timecounter.
>> >>>>> * @param[in] get The method to get the value of the simple
>> >>>>> timecounter.
>> >>>>> + * @param[in] at_tick The method to perform work under timecounter
>> lock
>> >>>>> + * protection at this tick, e.g. clear a pending flag.
>> >>>>> */
>> >>>>> RTEMS_INLINE_ROUTINE void
>> rtems_timecounter_simple_downcounter_tick(
>> >>>>> - rtems_timecounter_simple *tc,
>> >>>>> - rtems_timecounter_simple_get get
>> >>>>> + rtems_timecounter_simple *tc,
>> >>>>> + rtems_timecounter_simple_get get,
>> >>>>> + rtems_timecounter_simple_at_tick at_tick
>> >>>>> )
>> >>>>> {
>> >>>>> + ISR_lock_Context lock_context;
>> >>>>> uint32_t current;
>> >>>>>
>> >>>>> + _Timecounter_Acquire( &lock_context );
>> >>>>> +
>> >>>>> + ( *at_tick )( tc );
>> >>>>> +
>> >>>>> current = rtems_timecounter_simple_scale(
>> >>>>> tc,
>> >>>>> tc->real_interval - ( *get )( tc )
>> >>>>> );
>> >>>>>
>> >>>>> - _Timecounter_Tick_simple( tc->binary_interval, current );
>> >>>>> + _Timecounter_Tick_simple( tc->binary_interval, current,
>> >>>>> &lock_context );
>> >>>>> }
>> >>>>>
>> >>>>> /**
>> >>>>> @@ -220,17 +235,25 @@ RTEMS_INLINE_ROUTINE void
>> >>>>> rtems_timecounter_simple_downcounter_tick(
>> >>>>> *
>> >>>>> * @param[in] tc The simple timecounter.
>> >>>>> * @param[in] get The method to get the value of the simple
>> >>>>> timecounter.
>> >>>>> + * @param[in] at_tick The method to perform work under timecounter
>> lock
>> >>>>> + * protection at this tick, e.g. clear a pending flag.
>> >>>>> */
>> >>>>> RTEMS_INLINE_ROUTINE void rtems_timecounter_simple_upcounter_tick(
>> >>>>> - rtems_timecounter_simple *tc,
>> >>>>> - rtems_timecounter_simple_get get
>> >>>>> + rtems_timecounter_simple *tc,
>> >>>>> + rtems_timecounter_simple_get get,
>> >>>>> + rtems_timecounter_simple_at_tick at_tick
>> >>>>> )
>> >>>>> {
>> >>>>> + ISR_lock_Context lock_context;
>> >>>>> uint32_t current;
>> >>>>>
>> >>>>> + _Timecounter_Acquire( &lock_context );
>> >>>>> +
>> >>>>> + ( *at_tick )( tc );
>> >>>>> +
>> >>>>> current = rtems_timecounter_simple_scale( tc, ( *get )( tc ) );
>> >>>>>
>> >>>>> - _Timecounter_Tick_simple( tc->binary_interval, current );
>> >>>>> + _Timecounter_Tick_simple( tc->binary_interval, current,
>> >>>>> &lock_context );
>> >>>>> }
>> >>>>>
>> >>>>> /**
>> >>>>> diff --git a/cpukit/score/include/rtems/score/timecounter.h
>> >>>>> b/cpukit/score/include/rtems/score/timecounter.h
>> >>>>> index 0d17cc7..0e611b5 100644
>> >>>>> --- a/cpukit/score/include/rtems/score/timecounter.h
>> >>>>> +++ b/cpukit/score/include/rtems/score/timecounter.h
>> >>>>> @@ -26,6 +26,8 @@
>> >>>>> #include <sys/time.h>
>> >>>>> #include <sys/timetc.h>
>> >>>>>
>> >>>>> +#include <rtems/score/isrlock.h>
>> >>>>> +
>> >>>>> #ifdef __cplusplus
>> >>>>> extern "C" {
>> >>>>> #endif /* __cplusplus */
>> >>>>> @@ -161,6 +163,31 @@ void _Timecounter_Install( struct timecounter
>> *tc
>> >>>>> );
>> >>>>> void _Timecounter_Tick( void );
>> >>>>>
>> >>>>> /**
>> >>>>> + * @brief Lock to protect the timecounter mechanic.
>> >>>>> + */
>> >>>>> +ISR_LOCK_DECLARE( extern, _Timecounter_Lock )
>> >>>>> +
>> >>>>> +/**
>> >>>>> + * @brief Acquires the timecounter lock.
>> >>>>> + *
>> >>>>> + * @param[in] lock_context The lock context.
>> >>>>> + *
>> >>>>> + * See _Timecounter_Tick_simple().
>> >>>>> + */
>> >>>>> +#define _Timecounter_Acquire( lock_context ) \
>> >>>>> + _ISR_lock_ISR_disable_and_acquire( &_Timecounter_Lock,
>> lock_context )
>> >>>>> +
>> >>>>> +/**
>> >>>>> + * @brief Releases the timecounter lock.
>> >>>>> + *
>> >>>>> + * @param[in] lock_context The lock context.
>> >>>>> + *
>> >>>>> + * See _Timecounter_Tick_simple().
>> >>>>> + */
>> >>>>> +#define _Timecounter_Release(lock_context) \
>> >>>>> + _ISR_lock_Release_and_ISR_enable(&_Timecounter_Lock,
>> lock_context)
>> >>>>> +
>> >>>>> +/**
>> >>>>> * @brief Performs a simple timecounter tick.
>> >>>>> *
>> >>>>> * This is a special purpose tick function for simple timecounter
>> to
>> >>>>> support
>> >>>>> @@ -169,8 +196,14 @@ void _Timecounter_Tick( void );
>> >>>>> * @param[in] delta The time in timecounter ticks elapsed since the
>> >>>>> last call
>> >>>>> * to _Timecounter_Tick_simple().
>> >>>>> * @param[in] offset The current value of the timecounter.
>> >>>>> - */
>> >>>>> -void _Timecounter_Tick_simple( uint32_t delta, uint32_t offset );
>> >>>>> + * @param[in] lock_context The lock context of the corresponding
>> >>>>> + * _Timecounter_Acquire().
>> >>>>> + */
>> >>>>> +void _Timecounter_Tick_simple(
>> >>>>> + uint32_t delta,
>> >>>>> + uint32_t offset,
>> >>>>> + ISR_lock_Context *lock_context
>> >>>>> +);
>> >>>>>
>> >>>>> /**
>> >>>>> * @brief The wall clock time in seconds.
>> >>>>> diff --git a/cpukit/score/src/kern_tc.c b/cpukit/score/src/kern_tc.c
>> >>>>> index f6a1136..4257533 100644
>> >>>>> --- a/cpukit/score/src/kern_tc.c
>> >>>>> +++ b/cpukit/score/src/kern_tc.c
>> >>>>> @@ -64,7 +64,9 @@ __FBSDID("$FreeBSD r284178
>> 2015-06-09T11:49:56Z$");
>> >>>>> #ifdef __rtems__
>> >>>>> #include <limits.h>
>> >>>>> #include <rtems.h>
>> >>>>> -ISR_LOCK_DEFINE(static, _Timecounter_Lock, "Timecounter");
>> >>>>> +ISR_LOCK_DEFINE(, _Timecounter_Lock, "Timecounter")
>> >>>>> +#define _Timecounter_Release(lock_context) \
>> >>>>> + _ISR_lock_Release_and_ISR_enable(&_Timecounter_Lock,
>> lock_context)
>> >>>>> #define hz rtems_clock_get_ticks_per_second()
>> >>>>> #define printf(...)
>> >>>>> #define log(...)
>> >>>>> @@ -1383,7 +1385,7 @@ tc_windup(void)
>> >>>>> #ifdef __rtems__
>> >>>>> ISR_lock_Context lock_context;
>> >>>>>
>> >>>>> - _ISR_lock_ISR_disable_and_acquire(&_Timecounter_Lock,
>> >>>>> &lock_context);
>> >>>>> + _Timecounter_Acquire(&lock_context);
>> >>>>> #endif /* __rtems__ */
>> >>>>>
>> >>>>> /*
>> >>>>> @@ -1538,7 +1540,7 @@ tc_windup(void)
>> >>>>> timekeep_push_vdso();
>> >>>>> #endif /* __rtems__ */
>> >>>>> #ifdef __rtems__
>> >>>>> - _ISR_lock_Release_and_ISR_enable(&_Timecounter_Lock,
>> >>>>> &lock_context);
>> >>>>> + _Timecounter_Release(&lock_context);
>> >>>>> #endif /* __rtems__ */
>> >>>>> }
>> >>>>>
>> >>>>> @@ -1963,14 +1965,12 @@ _Timecounter_Tick(void)
>> >>>>> }
>> >>>>> #ifdef __rtems__
>> >>>>> void
>> >>>>> -_Timecounter_Tick_simple(uint32_t delta, uint32_t offset)
>> >>>>> +_Timecounter_Tick_simple(uint32_t delta, uint32_t offset,
>> >>>>> + ISR_lock_Context *lock_context)
>> >>>>> {
>> >>>>> struct bintime bt;
>> >>>>> struct timehands *th;
>> >>>>> uint32_t ogen;
>> >>>>> - ISR_lock_Context lock_context;
>> >>>>> -
>> >>>>> - _ISR_lock_ISR_disable_and_acquire(&_Timecounter_Lock,
>> >>>>> &lock_context);
>> >>>>>
>> >>>>> th = timehands;
>> >>>>> ogen = th->th_generation;
>> >>>>> @@ -1997,7 +1997,7 @@ _Timecounter_Tick_simple(uint32_t delta,
>> uint32_t
>> >>>>> offset)
>> >>>>> time_second = th->th_microtime.tv_sec;
>> >>>>> time_uptime = th->th_offset.sec;
>> >>>>>
>> >>>>> - _ISR_lock_Release_and_ISR_enable(&_Timecounter_Lock,
>> >>>>> &lock_context);
>> >>>>> + _Timecounter_Release(lock_context);
>> >>>>>
>> >>>>> _Watchdog_Tick();
>> >>>>> }
>> >>>>> diff --git a/doc/bsp_howto/clock.t b/doc/bsp_howto/clock.t
>> >>>>> index f58b898..2891bb2 100644
>> >>>>> --- a/doc/bsp_howto/clock.t
>> >>>>> +++ b/doc/bsp_howto/clock.t
>> >>>>> @@ -89,6 +89,13 @@ static uint32_t some_tc_get(
>> >>>>> rtems_timecounter_simple *tc )
>> >>>>> return some.counter;
>> >>>>> @}
>> >>>>>
>> >>>>> +static void some_tc_at_tick( rtems_timecounter_simple *tc )
>> >>>>> +@{
>> >>>>> + /*
>> >>>>> + * Do work necessary at the clock tick interrupt, e.g. clear a
>> >>>>> pending flag.
>> >>>>> + */
>> >>>>> +@}
>> >>>>> +
>> >>>>> static bool some_tc_is_pending( rtems_timecounter_simple *tc )
>> >>>>> @{
>> >>>>> return some.is_pending;
>> >>>>> @@ -105,7 +112,11 @@ static uint32_t some_tc_get_timecount( struct
>> >>>>> timecounter *tc )
>> >>>>>
>> >>>>> static void some_tc_tick( void )
>> >>>>> @{
>> >>>>> - rtems_timecounter_simple_downcounter_tick( &some_tc, some_tc_get
>> );
>> >>>>> + rtems_timecounter_simple_downcounter_tick(
>> >>>>> + &some_tc,
>> >>>>> + some_tc_get,
>> >>>>> + some_tc_at_tick
>> >>>>> + );
>> >>>>> @}
>> >>>>>
>> >>>>> static void some_support_initialize_hardware( void )
>> >>>>> --
>> >>>>> 2.7.0
>> >>>>>
>> >>>>> _______________________________________________
>> >>>>> devel mailing list
>> >>>>> devel at rtems.org
>> >>>>> http://lists.rtems.org/mailman/listinfo/devel
>> >>>>>
>> >>>>
>> >>>>
>> >>>
>> >>>
>> >>> --
>> >>>
>> >>> ______________________________
>> >>>
>> >>> <http://www.tallertechnologies.com>
>> >>>
>> >>>
>> >>> Marcos Díaz
>> >>>
>> >>> Software Engineer
>> >>>
>> >>>
>> >>> San Lorenzo 47, 3rd Floor, Office 5
>> >>>
>> >>> Córdoba, Argentina
>> >>>
>> >>>
>> >>> Phone: +54 351 4217888 / +54 351 4218211/ +54 351 7617452
>> >>>
>> >>> Skype: markdiaz22
>> >>>
>> >>>
>> >>
>> >
>> >
>> > --
>> >
>> > ______________________________
>> >
>> > <http://www.tallertechnologies.com>
>> >
>> >
>> > Marcos Díaz
>> >
>> > Software Engineer
>> >
>> >
>> > San Lorenzo 47, 3rd Floor, Office 5
>> >
>> > Córdoba, Argentina
>> >
>> >
>> > Phone: +54 351 4217888 / +54 351 4218211/ +54 351 7617452
>> >
>> > Skype: markdiaz22
>>
>
>
>
> --
>
> ______________________________
>
> <http://www.tallertechnologies.com>
>
>
> Marcos Díaz
>
> Software Engineer
>
>
> San Lorenzo 47, 3rd Floor, Office 5
>
> Córdoba, Argentina
>
>
> Phone: +54 351 4217888 / +54 351 4218211/ +54 351 7617452
>
> Skype: markdiaz22
>
>
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