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Add support for tickless operation using the NXP LPC43xx

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This commit is contained in:
Gregory Nutt 2014-10-23 06:54:24 -06:00
parent a7a5c8cff3
commit b5fc30f1e8
5 changed files with 327 additions and 0 deletions
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6
arch/arm/src/lpc43xx/Kconfig
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@ -66,26 +66,32 @@ endchoice
config ARCH_FAMILY_LPC4310
bool
default y if ARCH_CHIP_LPC4310FBD144 || ARCH_CHIP_LPC4310FET100
select ARCH_HAVE_TICKLESS
config ARCH_FAMILY_LPC4320
bool
default y if ARCH_CHIP_LPC4320FBD144 || ARCH_CHIP_LPC4320FET100
select ARCH_HAVE_TICKLESS
config ARCH_FAMILY_LPC4330
bool
default y if ARCH_CHIP_LPC4330FBD144 || ARCH_CHIP_LPC4330FET100 || ARCH_CHIP_LPC4330FET180 || ARCH_CHIP_LPC4330FET256
select ARCH_HAVE_TICKLESS
config ARCH_FAMILY_LPC4350
bool
default y if ARCH_CHIP_LPC4350FBD208 || ARCH_CHIP_LPC4350FET180 || ARCH_CHIP_LPC4350FET256
select ARCH_HAVE_TICKLESS
config ARCH_FAMILY_LPC4353
bool
default y if ARCH_CHIP_LPC4353FBD208 || ARCH_CHIP_LPC4353FET180 || ARCH_CHIP_LPC4353FET256
select ARCH_HAVE_TICKLESS
config ARCH_FAMILY_LPC4357
bool
default y if ARCH_CHIP_LPC4357FET180 || ARCH_CHIP_LPC4357FBD208 || ARCH_CHIP_LPC4357FET256
select ARCH_HAVE_TICKLESS
choice
prompt "LPC43XX Boot Configuration"

4
arch/arm/src/lpc43xx/Make.defs
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@ -128,6 +128,10 @@ CHIP_CSRCS += lpc43_ssp.c
endif
endif
ifeq ($(CONFIG_LPC43_RIT),y)
CHIP_CSRCS += lpc43_rit.c
endif
ifeq ($(CONFIG_LPC43_I2C0),y)
CHIP_CSRCS += lpc43_i2c.c
else

1
arch/arm/src/lpc43xx/chip/lpc43_rit.h
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@ -41,6 +41,7 @@
************************************************************************************/
#include <nuttx/config.h>
#include "chip/lpc4310203050_memorymap.h"
/************************************************************************************
* Pre-processor Definitions

248
arch/arm/src/lpc43xx/lpc43_rit.c Normal file
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@ -0,0 +1,248 @@
/****************************************************************************
* arch/arm/src/lpc43/lpc43_rit.c
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* 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
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <arch/board/board.h>
#include <nuttx/config.h>
#include <nuttx/arch.h>
#include <errno.h>
#include "up_arch.h"
#include "chip/lpc43_rit.h"
#include "lpc43_rit.h"
#ifdef CONFIG_LPC43_RIT
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* 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.
*/
#define RIT_TIMER_RESOLUTION 250
/****************************************************************************
* Private Data
****************************************************************************/
static double sec_per_tick;
static uint64_t internal_timer, alarm;
struct timespec g_ts;
/****************************************************************************
* Private Functions
****************************************************************************/
static int lpc43_RIT_isr(int irq, FAR void *context)
{
irqstate_t flags;
flags = irqsave();
putreg32(RIT_CTRL_INT,LPC43_RIT_CTRL);
internal_timer += (uint64_t)RIT_TIMER_RESOLUTION;
if (alarm > 0 && internal_timer >= alarm)
{
/* handle expired alarm */
g_ts.tv_sec = (uint32_t)(internal_timer / 1000000000);
g_ts.tv_nsec = (uint32_t)(internal_timer % 1000000000);
sched_alarm_expiration(&g_ts);
}
irqrestore(flags);
return OK;
}
static inline void lpc43_load_RIT_timer(uint32_t value)
{
putreg32(value, LPC43_RIT_COUNTER);
}
static inline void lpc43_load_RIT_compare(uint32_t value)
{
putreg32(value, LPC43_RIT_COMPVAL);
}
static inline void lpc43_set_RIT_timer_mask(uint32_t value)
{
putreg32(value, LPC43_RIT_MASK);
}
static inline uint32_t lpc43_read_RIT_timer(void)
{
return getreg32(LPC43_RIT_COUNTER);
}
static inline void lpc43_RIT_timer_start(void)
{
uint32_t regval;
regval = getreg32(LPC43_RIT_CTRL);
/* Since a cycle timer is in use here, the timer clear is enabled. If
* using the timer directly, this likely should not be used. Also, clear
* the interrupt flag.
*/
regval |= RIT_CTRL_INT | RIT_CTRL_EN | RIT_CTRL_ENCLR;
putreg32(regval, LPC43_RIT_CTRL);
}
static inline void lpc43_RIT_timer_stop(void)
{
uint32_t regval;
regval = getreg32(LPC43_RIT_CTRL);
regval &= ~RIT_CTRL_EN;
putreg32(regval, LPC43_RIT_CTRL);
}
/****************************************************************************
* Public Functions
****************************************************************************/
void up_timer_initialize(void)
{
uint32_t ticks_per_int;
uint32_t mask_bits = 0;
uint32_t mask_test = 0x80000000;
lpc43_RIT_timer_stop();
lpc43_load_RIT_timer(0);
internal_timer = 0;
/* Set up the IRQ here */
irq_attach(LPC43M4_IRQ_RITIMER, lpc43_RIT_isr);
/* Compute how many seconds per tick we have on the main clock. If it is
* 204MHz for example, then there should be about 4.90ns per tick
*/
sec_per_tick = (double)1.0/(double)LPC43_CCLK;
/* Given an RIT_TIMER_RESOLUTION, compute how many ticks it will take to
* reach that resolution. For example, if we wanted a 1/4uS timer
* 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.
*/
ticks_per_int = RIT_TIMER_RESOLUTION/(1000000000*sec_per_tick)+1;
/* Now we need to compute the mask that will let us set up to generate an
* interrupt every 1/4uS. This isn't "tickless" per-se, and probably
* should be implemented differently, however it allows me to create a
* 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.
*/
while(!((mask_test >> mask_bits) & ticks_per_int)) mask_bits++;
lldbg("mask_bits = %d, mask = %X, ticks_per_int = %d\r\n",
mask_bits, (0xFFFFFFFF<<(32 - mask_bits)), ticks_per_int);
/* Set the mask and compare value so we get interrupts every
* RIT_TIMER_RESOLUTION cycles.
*/
lpc43_set_RIT_timer_mask((0xFFFFFFFF << (32 - mask_bits)));
lpc43_load_RIT_compare(ticks_per_int);
/* Turn on the IRQ */
up_enable_irq(LPC43M4_IRQ_RITIMER);
/* Start the timer */
lpc43_RIT_timer_start();
}
int up_timer_gettime(FAR struct timespec *ts)
{
ts->tv_sec = (uint32_t)(internal_timer / 1000000000);
ts->tv_nsec = (uint32_t)(internal_timer % 1000000000);
return OK;
}
int up_alarm_cancel(FAR struct timespec *ts)
{
ts->tv_sec = (uint32_t)(internal_timer / 1000000000);
ts->tv_nsec = (uint32_t)(internal_timer % 1000000000);
alarm = 0;
return OK;
}
int up_alarm_start(FAR const struct timespec *ts)
{
alarm = (uint64_t)ts->tv_sec * (uint64_t)1000000000 + (uint64_t)ts->tv_nsec;
return OK;
}
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.
*/
return up_alarm_cancel(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.
*/
return up_alarm_start(ts);
}
#endif /* CONFIG_LPC43_RIT */

68
arch/arm/src/lpc43xx/lpc43_rit.h Normal file
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@ -0,0 +1,68 @@
/*****************************************************************************
* arch/arm/src/lpc43xx/lpc43_rit.h
*
* Copyright (C) 2012 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*****************************************************************************/
#ifndef __ARCH_ARM_SRC_LPC43XX_LPC43_RIT_H
#define __ARCH_ARM_SRC_LPC43XX_LPC43_RIT_H
/*****************************************************************************
* Included Files
*****************************************************************************/
#include <nuttx/config.h>
/*****************************************************************************
* Pre-processor Definitions
*****************************************************************************/
/*****************************************************************************
* Public Types
*****************************************************************************/
/*****************************************************************************
* Public Data
*****************************************************************************/
/************************************************************************************
* Public Functions
*****************************************************************************/
void up_timer_initialize(void);
int up_timer_gettime(FAR struct timespec *ts);
int up_alarm_cancel(FAR struct timespec *ts);
int up_alarm_start(FAR const struct timespec *ts);
int up_timer_cancel(FAR struct timespec *ts);
int up_timer_start(FAR const struct timespec *ts);
#endif /* __ARCH_ARM_SRC_LPC43XX_LPC43_RIT_H */