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BCM2708: Add system timer register definitions and a partial implementation of the tickless mode timer.

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This commit is contained in:
Gregory Nutt 2017-10-17 13:42:52 -06:00
parent d101fad026
commit ea23268f34
5 changed files with 548 additions and 2 deletions
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1
arch/arm/Kconfig
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@ -29,6 +29,7 @@ config ARCH_CHIP_BCM2708
select ARCH_HAVE_LOWVECTORS
select ARCH_HAVE_MMU
select ARCH_USE_MMU
select ARCH_HAVE_TICKLESS
config ARCH_CHIP_C5471
bool "TMS320 C5471"

2
arch/arm/src/bcm2708/Make.defs
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@ -72,7 +72,7 @@ endif
# BCM2708-specific source files.
CHIP_CSRCS = bcm_boot.c bcm_memorymap.c bcm_clockconfig.c bcm_irq.c
CHIP_CSRCS += bcm_gpio.c
CHIP_CSRCS += bcm_tickless.c bcm_gpio.c
ifeq ($(CONFIG_BCM2708_GPIO_IRQ),y)
CHIP_CSRCS += bcm_gpioint.c

456
arch/arm/src/bcm2708/bcm_tickless.c Normal file
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@ -0,0 +1,456 @@
/****************************************************************************
* arch/arm/src/bcm2708/bcm_tickless.c
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Authors: 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.
*
****************************************************************************/
/****************************************************************************
* Tickless OS Support.
*
* When CONFIG_SCHED_TICKLESS is enabled, all support for timer interrupts
* is suppressed and the platform specific code is expected to provide the
* following custom functions.
*
* void arm_timer_initialize(void): Initializes the timer facilities.
* Called early in the initialization sequence (by up_intialize()).
* int up_timer_gettime(FAR struct timespec *ts): Returns the current
* time from the platform specific time source.
* int up_timer_cancel(void): Cancels the interval timer.
* int up_timer_start(FAR const struct timespec *ts): Start (or re-starts)
* the interval timer.
*
* The RTOS will provide the following interfaces for use by the platform-
* specific interval timer implementation:
*
* void sched_timer_expiration(void): Called by the platform-specific
* logic when the interval timer expires.
*
****************************************************************************/
/****************************************************************************
* BCM2708 Timer Usage
*
* This implementation uses the BCM2708 64-bit system timer. The 64-bit
* timer provides the running time; comparison registers are used to
* generate interval interrupt.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
#include <stdbool.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/clock.h>
#include <nuttx/irq.h>
#include "up_arch.h"
#include "chip/bcm2708_systimr.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifndef CONFIG_SCHED_TICKLESS
# error CONFIG_SCHED_TICKLESS is required
#endif
#if CONFIG_USEC_PER_TICK != 1
# error CONFIG_USEC_PER_TICK=1 is required
#endif
/****************************************************************************
* Private Data
****************************************************************************/
static volatile uint64_t g_systimr_start; /* Timer interval timer started */
static volatile uint64_t g_systimr_interval; /* Duration of the interval timer */
static volatile bool g_systimr_running; /* True if the interval timer is running */
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: bcm_read_systimr
*
* Description:
* Read the 64-bit system timer
*
* Input Parameters:
* None
*
* Returned Value:
* The 64-bit system timer
*
* Assumptions:
* Called from a critical section.
*
****************************************************************************/
static uint64_t bcm_read_systimr(void)
{
uint32_t check;
uint32_t chi;
uint32_t clo;
/* Loop to handle overflow from CLO to CHI (should be a rare event) */
do
{
chi = getreg32(BCM_SYSTIMR_CHI);
clo = getreg32(BCM_SYSTIMR_CLO);
check = getreg32(BCM_SYSTIMR_CHI);
}
while (chi != check);
/* Then return the full 64-bit value */
return ((uint64_t)chi << 32) | (uint64_t)clo;
}
/****************************************************************************
* Name: bcm_convert_systimr
*
* Description:
* Convert the 64-bit system timer value to a standard struct ts
*
* Input Parameters:
* ts = Location to return the converted system timer value
*
* Returned Value:
* None
*
****************************************************************************/
static void bcm_convert_systimr(uint64_t usec, FAR struct timespec *ts)
{
uint32_t sec;
/* Convert and return the timer value */
sec = (uint32_t)(usec / USEC_PER_SEC);
ts->tv_sec = sec;
ts->tv_nsec = (usec - (sec * USEC_PER_SEC)) * NSEC_PER_USEC;
}
/****************************************************************************
* Name: bcm_systimr_interrupt
*
* Description:
* System tmer compare interrupt
*
* Input Parameters:
* Standard interrupt input parameters
*
* Returned Value:
* Always returns OK
*
* Assumptions:
* Interrupts ar disabled
*
****************************************************************************/
static int bcm_systimr_interrupt(int irq, FAR void *context, FAR void *arg)
{
#warning Missing logic
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: arm_timer_initialize
*
* Description:
* Initializes all platform-specific timer facilities. This function is
* called early in the initialization sequence by up_intialize().
* On return, the current up-time should be available from
* up_timer_gettime() and the interval timer is ready for use (but not
* actively timing.
*
* Provided by platform-specific code and called from the architecture-
* specific logic.
*
* Input Parameters:
* None
*
* Returned Value:
* None
*
* Assumptions:
* Called early in the initialization sequence before any special
* concurrency protections are required.
*
****************************************************************************/
void arm_timer_initialize(void)
{
/* Nothing needs to be done... we inherit the 1MHz timer from the
* bootloader.
*/
}
/****************************************************************************
* Name: up_timer_gettime
*
* Description:
* Return the elapsed time since power-up (or, more correctly, since
* arm_timer_initialize() was called). This function is functionally
* equivalent to:
*
* int clock_gettime(clockid_t clockid, FAR struct timespec *ts);
*
* when clockid is CLOCK_MONOTONIC.
*
* This function provides the basis for reporting the current time and
* also is used to eliminate error build-up from small errors in interval
* time calculations.
*
* Provided by platform-specific code and called from the RTOS base code.
*
* Input Parameters:
* ts - Provides the location in which to return the up-time.
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned on
* any failure.
*
* Assumptions:
* Called from the normal tasking context. The implementation must
* provide whatever mutual exclusion is necessary for correct operation.
* This can include disabling interrupts in order to assure atomic register
* operations.
*
****************************************************************************/
#ifndef CONFIG_CLOCK_TIMEKEEPING
int up_timer_gettime(FAR struct timespec *ts)
{
uint64_t now;
irqstate_t flags;
DEBUGASSERT(ts != NULL);
/* Read the 64-bit system timer */
flags = enter_critical_section();
now = bcm_read_systimr();
leave_critical_section(flags);
/* Return the value of the timer */
bcm_convert_systimr(now, ts);
return OK;
}
#else
int up_timer_getcounter(FAR uint64_t *cycles)
{
irqstate_t flags;
DEBUGASSERT(cycles != NULL);
flags = enter_critical_section();
*cycles = bcm_read_systimr();
leave_critical_section(flags);
return OK;
}
#endif /* CONFIG_CLOCK_TIMEKEEPING */
/****************************************************************************
* Name: up_timer_getmask
*
* Description:
* To be provided
*
* Input Parameters:
* mask - Location to return the 64-bit mask
*
* Returned Value:
* None
*
****************************************************************************/
#ifdef CONFIG_CLOCK_TIMEKEEPING
void up_timer_getmask(FAR uint64_t *mask)
{
DEBUGASSERT(mask != NULL);
*mask = 0xffffffffull;
}
#endif /* CONFIG_CLOCK_TIMEKEEPING */
/****************************************************************************
* Name: up_timer_cancel
*
* Description:
* Cancel the interval timer and return the time remaining on the timer.
* These two steps need to be as nearly atomic as possible.
* sched_timer_expiration() will not be called unless the timer is
* restarted with up_timer_start().
*
* If, as a race condition, the timer has already expired when this
* function is called, then that pending interrupt must be cleared so
* that up_timer_start() and the remaining time of zero should be
* returned.
*
* NOTE: This function may execute at a high rate with no timer running (as
* when pre-emption is enabled and disabled).
*
* Provided by platform-specific code and called from the RTOS base code.
*
* Input Parameters:
* ts - Location to return the remaining time. Zero should be returned
* if the timer is not active. ts may be zero in which case the
* time remaining is not returned.
*
* Returned Value:
* Zero (OK) is returned on success. A call to up_timer_cancel() when
* the timer is not active should also return success; a negated errno
* value is returned on any failure.
*
* Assumptions:
* May be called from interrupt level handling or from the normal tasking
* level. Interrupts may need to be disabled internally to assure
* non-reentrancy.
*
****************************************************************************/
int up_timer_cancel(FAR struct timespec *ts)
{
uint64_t elapsed = 0;
irqstate_t flags;
DEBUGASSERT(ts != NULL);
/* Disable the comparison interrupt */
flags = enter_critical_section();
#warning Missing logic
/* Check if the timer was actually running */
if (!g_systimr_running)
{
goto errout;
}
g_systimr_running = false;
/* Get the time elapsed time since the interval timer was started */
elapsed = bcm_read_systimr() - g_systimr_start;
if (elapsed >= g_systimr_interval)
{
goto errout;
}
g_systimr_interval = 0;
/* Return the value remaining on the timer */
leave_critical_section(flags);
bcm_convert_systimr(g_systimr_interval - elapsed, ts);
return OK;
errout:
g_systimr_running = false;
g_systimr_interval = 0;
leave_critical_section(flags);
ts->tv_sec = 0;
ts->tv_nsec = 0;
return -ENODATA;
}
/****************************************************************************
* Name: up_timer_start
*
* Description:
* Start the interval timer. sched_timer_expiration() will be
* called at the completion of the timeout (unless up_timer_cancel
* is called to stop the timing.
*
* Provided by platform-specific code and called from the RTOS base code.
*
* Input Parameters:
* ts - Provides the time interval until sched_timer_expiration() is
* called.
*
* Returned Value:
* Zero (OK) is returned on success; a negated errno value is returned on
* any failure.
*
* Assumptions:
* May be called from interrupt level handling or from the normal tasking
* level. Interrupts may need to be disabled internally to assure
* non-reentrancy.
*
****************************************************************************/
int up_timer_start(FAR const struct timespec *ts)
{
irqstate_t flags;
uint64_t interval;
uint64_t now;
uint32_t cmp;
DEBUGASSERT(ts != NULL);
/* Convert the time to microseconds */
interval = (uint64_t)ts->tv_sec * USEC_PER_SEC +
(uint64_t)(ts->tv_nsec / NSEC_PER_USEC);
flags = enter_critical_section();
/* Configure and enable the comparison interrupt */
now = bcm_read_systimr();
cmp = (uint32_t)(now + interval);
#warning Missing logic
g_systimr_start = now;
g_systimr_interval = interval;
g_systimr_running = true;
leave_critical_section(flags);
return OK;
}

88
arch/arm/src/bcm2708/chip/bcm2708_systimr.h Normal file
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@ -0,0 +1,88 @@
/************************************************************************************
* arch/arm/src/bcm2708/chip/bcm2708_systimr.h
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Author: Alan Carvalho de Assis <acassis@gmail.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.
*
************************************************************************************/
#ifndef __ARCH_ARM_SRC_BCM2708_CHIP_BCM2780_SYSTIMR_H
#define __ARCH_ARM_SRC_BCM2708_CHIP_BCM2780_SYSTIMR_H
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include "chip/bcm2708_memorymap.h"
/************************************************************************************
* Pre-processor Definitions
************************************************************************************/
/* System Tmer Register Offsets *****************************************************/
#define BCM_SYSTIMR_C_OFFSET 0x0000 /* System Timer Control/Status */
#define BCM_SYSTIMR_CLO_OFFSET 0x0004 /* System Timer Counter Lower 32 bits */
#define BCM_SYSTIMR_CHI_OFFSET 0x0008 /* System Timer Counter Higher 32 bits */
#define BCM_SYSTIMR_C0_OFFSET 0x000c /* System Timer Compare 0 */
#define BCM_SYSTIMR_C1_OFFSET 0x0010 /* System Timer Compare 1 */
#define BCM_SYSTIMR_C2_OFFSET 0x0014 /* System Timer Compare 2 */
#define BCM_SYSTIMR_C3_OFFSET 0x0018 /* System Timer Compare 3 */
/* System Tmer Register Addresses ***************************************************/
#define BCM_SYSTIMR_C (BCM_SYSTMR_VBASE+BCM_SYSTIMR_C_OFFSET)
#define BCM_SYSTIMR_CLO (BCM_SYSTMR_VBASE+BCM_SYSTIMR_CLO_OFFSET)
#define BCM_SYSTIMR_CHI (BCM_SYSTMR_VBASE+BCM_SYSTIMR_CHI_OFFSET)
#define BCM_SYSTIMR_C0 (BCM_SYSTMR_VBASE+BCM_SYSTIMR_C0_OFFSET)
#define BCM_SYSTIMR_C1 (BCM_SYSTMR_VBASE+BCM_SYSTIMR_C1_OFFSET)
#define BCM_SYSTIMR_C2 (BCM_SYSTMR_VBASE+BCM_SYSTIMR_C2_OFFSET)
#define BCM_SYSTIMR_C3 (BCM_SYSTMR_VBASE+BCM_SYSTIMR_C3_OFFSET)
/* System Tmer Register Bit Definitions ****************************************************/
/* System Timer Control/Status */
#define SYSTIMR_C_M0 (1 << 0) /* Bit nn: System Timer Match 0 */
#define SYSTIMR_C_M1 (1 << 1) /* Bit nn: System Timer Match 1 */
#define SYSTIMR_C_M2 (1 << 2) /* Bit nn: System Timer Match 2 */
#define SYSTIMR_C_M3 (1 << 3) /* Bit nn: System Timer Match 3 */
/* System Timer Counter Lower 32 bits (32 bit counter value) */
/* System Timer Counter Higher 32 bits (32 bit counter value) */
/* System Timer Compare 0 (32 bit compare value) */
/* System Timer Compare 1 (32 bit compare value) */
/* System Timer Compare 2 (32 bit compare value) */
/* System Timer Compare 3 (32 bit compare value) */
#endif /* __ARCH_ARM_SRC_BCM2708_CHIP_BCM2780_SYSTIMR_H */

3
configs/pizero/nsh/defconfig
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@ -21,7 +21,6 @@ CONFIG_HOST_WINDOWS=y
CONFIG_INTELHEX_BINARY=y
CONFIG_MAX_TASKS=16
CONFIG_MAX_WDOGPARMS=2
CONFIG_MM_REGIONS=1
CONFIG_NFILE_DESCRIPTORS=8
CONFIG_NFILE_STREAMS=8
CONFIG_NSH_BUILTIN_APPS=y
@ -35,9 +34,11 @@ CONFIG_RAM_SIZE=369098752
CONFIG_RAM_START=0x00000000
CONFIG_RAW_BINARY=y
CONFIG_RR_INTERVAL=200
CONFIG_SCHED_TICKLESS=y
CONFIG_SCHED_WAITPID=y
CONFIG_SDCLONE_DISABLE=y
CONFIG_START_DAY=6
CONFIG_START_MONTH=12
CONFIG_START_YEAR=2011
CONFIG_USEC_PER_TICK=1
CONFIG_USER_ENTRYPOINT="nsh_main"