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Update to the LPC43xx RIT/Tickless code. From Brandon Warhurst

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This commit is contained in:
Gregory Nutt 2014-10-23 07:14:37 -06:00
parent c10f826ae3
commit cc0a5d6004
4 changed files with 40 additions and 13 deletions
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5
arch/arm/src/lpc43xx/Kconfig
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@ -203,6 +203,11 @@ config LPC43_RIT
bool "Repetitive Interrupt Timer (RIT)"
default n
config LPC43_RIT_RES
int "Interrupt schedule resolution (nS)"
default 250
depends on LPC43_RIT
config LPC43_RTC
bool "Real Time Clock (RTC)"
default n

3
arch/arm/src/lpc43xx/chip/lpc43_rit.h
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@ -2,7 +2,8 @@
* arch/arm/src/lpc43xx/lpc43_rit.h
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
* Author: Brandon Warhurst <warhurst_002@yahoo.com>
* Original Author: Gregory Nutt
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions

43
arch/arm/src/lpc43xx/lpc43_rit.c
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@ -33,6 +33,16 @@
*
****************************************************************************/
/****************************************************************************
* WARNING -- This code is currently *NOT* thread safe. No checking is done
* that one alarm call might not override an already enabled one.
* You might be able to handle this with some kind of cascading
* scheme where alarm receives the next value in a list of alarms
* all in the future.
*
* Brandon Warhurst
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
@ -53,13 +63,15 @@
* Pre-processor Definitions
****************************************************************************/
/* set the timer resolution at 1uS
/* Set the timer resolution at 1uS
*
* This is a battery waster, but I need this kind of resolution for 1-wire
* protocols... Until I can find a better way to implement them.
*/
*
* This should probable be Kconfig material.
*/
#define RIT_TIMER_RESOLUTION 250
#define RIT_TIMER_RESOLUTION CONFIG_LPC43_RIT_RES
/****************************************************************************
* Private Data
@ -166,6 +178,7 @@ void up_timer_initialize(void)
* resolution, that would be 250ns resolution. The timer is an integer
* value, although maybe this should change, but that means
* 250/1000000000*0.00000000490 = 51.02 ticks or 51 ticks, roughly.
* We round up by 1 tick.
*/
ticks_per_int = RIT_TIMER_RESOLUTION/(1000000000*sec_per_tick)+1;
@ -176,10 +189,10 @@ void up_timer_initialize(void)
* 64 bit nanosecond timer than can "free-run" by being updated every
* RIT_TIMER_RESOLUTION cycles. I would have implemented the better
* approach, but I didn't have a good way to determine how to manage a
* 32 bit ns timer. Every 21 seconds the thing rolls over, so you'd have
* to set up the compare interrupt to handle the roll over. It WOULD be
* fewer interrupts, but it seemed to make things more complicated. When
* I have a better idea, I'll change this.
* 32 bit ns timer. Every 21 seconds the thing rolls over@ 204MHz, so
* you'd have to set up the compare interrupt to handle the roll over. It
* WOULD be fewer interrupts, but it seemed to make things more
* complicated. When I have a better idea, I'll change this.
*/
while(!((mask_test >> mask_bits) & ticks_per_int)) mask_bits++;
@ -221,6 +234,11 @@ int up_alarm_cancel(FAR struct timespec *ts)
int up_alarm_start(FAR const struct timespec *ts)
{
/* According to the docs, this version should expect to receive the time
* in the future when the alarm should expire. So that's the way it's
* coded.
*/
alarm = (uint64_t)ts->tv_sec * (uint64_t)1000000000 + (uint64_t)ts->tv_nsec;
return OK;
}
@ -230,6 +248,7 @@ int up_timer_cancel(FAR struct timespec *ts)
/* Currently this is just an alarm and both are implemented. This is *NOT*
* how it is supposed to be and will be corrected, but for now, this is a
* simple way to implement both.
* FIXME
*/
return up_alarm_cancel(ts);
@ -237,12 +256,14 @@ int up_timer_cancel(FAR struct timespec *ts)
int up_timer_start(FAR const struct timespec *ts)
{
/* Currently this is just an alarm and both are implemented. This is *NOT*
* how it is supposed to be and will be corrected, but for now, this is a
* simple way to implement both.
/* According to the docs, this version should basically compute the time
* in the future when an alarm should go off. That is the way it could
* potentially be implemented, so that's the way I did it.
*/
return up_alarm_start(ts);
alarm = internal_timer;
alarm += (uint64_t)ts->tv_sec * (uint64_t)1000000000 + (uint64_t)ts->tv_nsec;
return OK;
}
#endif /* CONFIG_LPC43_RIT */

2
arch/arm/src/lpc43xx/lpc43_rit.h
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@ -2,7 +2,7 @@
* arch/arm/src/lpc43xx/lpc43_rit.h
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
* Author: Brandon Warhurst <warhurst_002@yahoo.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions