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arch/arm/src/armv7-m: Implement SYSTICK timer driver

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This commit is contained in:
Xiang Xiao 2018-08-23 10:08:11 -06:00 • committed by Gregory Nutt
parent 2c93467436
commit 22a44465e4
3 changed files with 428 additions and 0 deletions
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6
arch/arm/src/armv7-m/Kconfig
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@ -255,3 +255,9 @@ config ARMV7M_ITMSYSLOG_SWODIV
range 1 8192
endif # ARMV7M_ITMSYSLOG
config ARMV7M_SYSTICK
bool "SysTick timer driver"
depends on TIMER
---help---
Enable SysTick timer driver.

91
arch/arm/src/armv7-m/systick.h Normal file
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@ -0,0 +1,91 @@
/****************************************************************************
* arch/arm/src/armv7-m/systick.h
*
* Copyright (C) 2018 Pinecone Inc. All rights reserved.
* Author: Xiang Xiao <xiaoxiang@pinecone.net>
*
* 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_ARMV7_M_SYSTICK_H
#define __ARCH_ARM_SRC_ARMV7_M_SYSTICK_H
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/timers/timer.h>
/****************************************************************************
* Public Function Prototypes
****************************************************************************/
#ifdef __cplusplus
#define EXTERN extern "C"
extern "C"
{
#else
#define EXTERN extern
#endif
/****************************************************************************
* Name: systick_initialize
*
* Description:
* This function initialize SYSTICK hardware module which is part of NVIC
* and return an instance of a "lower half" timer interface.
*
* Input parameters:
* coreclk - false if SYSTICK working clock come from the external
* reference clock, otherwise true.
* freq - The clock frequency in Hz. If freq is zero, calculate the value
* from NVIC_SYSTICK_CALIB register.
* minor - The timer driver minor number, skip the registration if minor
* < 0.
*
* Returned Value:
* On success, a non-NULL timer_lowerhalf_s is returned to the caller.
* In the event of any failure, a NULL value is returned.
*
****************************************************************************/
#ifdef CONFIG_ARMV7M_SYSTICK
struct timer_lowerhalf_s *systick_initialize(bool coreclk, unsigned int freq,
int minor);
#else
# define systick_initialize(coreclk, freq, minor) NULL
#endif /* CONFIG_ARMV7M_SYSTICK */
#undef EXTERN
#ifdef __cplusplus
}
#endif
#endif /* __ARCH_ARM_SRC_ARMV7_M_SYSTICK_H */

331
arch/arm/src/armv7-m/up_systick.c Normal file
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@ -0,0 +1,331 @@
/****************************************************************************
* arch/arm/src/armv7-m/up_systick.c
*
* Copyright (C) 2018 Pinecone Inc. All rights reserved.
* Author: Xiang Xiao <xiaoxiang@pinecone.net>
*
* 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 <nuttx/config.h>
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <stdio.h>
#include "nvic.h"
#include "systick.h"
#include "up_arch.h"
#ifdef CONFIG_ARMV7M_SYSTICK
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define NVIC_IRQ_SYSTICK 15 /* Vector 15: System tick */
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure provides the private representation of the "lower-half"
* driver state structure. This structure must be cast-compatible with the
* timer_lowerhalf_s structure.
*/
struct systick_lowerhalf_s
{
const struct timer_ops_s *ops; /* Lower half operations */
uint32_t freq; /* Timer working clock frequency(Hz) */
tccb_t callback; /* Current user interrupt callback */
void *arg; /* Argument passed to upper half callback */
uint32_t *next_interval;
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
static int systick_start(FAR struct timer_lowerhalf_s *lower_);
static int systick_stop(FAR struct timer_lowerhalf_s *lower_);
static int systick_getstatus(FAR struct timer_lowerhalf_s *lower_,
FAR struct timer_status_s *status);
static int systick_settimeout(FAR struct timer_lowerhalf_s *lower_,
uint32_t timeout);
static void systick_setcallback(FAR struct timer_lowerhalf_s *lower_,
tccb_t callback, FAR void *arg);
static int systick_maxtimeout(FAR struct timer_lowerhalf_s *lower_,
uint32_t *maxtimeout);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct timer_ops_s g_systick_ops =
{
.start = systick_start,
.stop = systick_stop,
.getstatus = systick_getstatus,
.settimeout = systick_settimeout,
.setcallback = systick_setcallback,
.maxtimeout = systick_maxtimeout,
};
static struct systick_lowerhalf_s g_systick_lower =
{
.ops = &g_systick_ops,
};
/****************************************************************************
* Private Functions
****************************************************************************/
static inline uint64_t usec_from_count(uint32_t count, uint32_t freq)
{
return (uint64_t)count * USEC_PER_SEC / freq;
}
static inline uint64_t usec_to_count(uint32_t usec, uint32_t freq)
{
return (uint64_t)usec * freq / USEC_PER_SEC;
}
static bool systick_is_running(void)
{
return !!(getreg32(NVIC_SYSTICK_CTRL) & NVIC_SYSTICK_CTRL_ENABLE);
}
static bool systick_irq_pending(struct systick_lowerhalf_s *lower)
{
if (lower->next_interval)
{
return false; /* Interrupt is in process */
}
else
{
return !!(getreg32(NVIC_INTCTRL) & NVIC_INTCTRL_PENDSTSET);
}
}
static int systick_start(FAR struct timer_lowerhalf_s *lower_)
{
putreg32(0, NVIC_SYSTICK_CURRENT);
modifyreg32(NVIC_SYSTICK_CTRL, 0, NVIC_SYSTICK_CTRL_ENABLE);
return 0;
}
static int systick_stop(FAR struct timer_lowerhalf_s *lower_)
{
modifyreg32(NVIC_SYSTICK_CTRL, NVIC_SYSTICK_CTRL_ENABLE, 0);
return 0;
}
static int systick_getstatus(FAR struct timer_lowerhalf_s *lower_,
FAR struct timer_status_s *status)
{
struct systick_lowerhalf_s *lower = (struct systick_lowerhalf_s *)lower_;
irqstate_t flags = enter_critical_section();
status->flags = lower->callback ? TCFLAGS_HANDLER : 0;
status->flags |= systick_is_running() ? TCFLAGS_ACTIVE : 0;
status->timeout = usec_from_count(getreg32(NVIC_SYSTICK_RELOAD),
lower->freq);
status->timeleft = usec_from_count(getreg32(NVIC_SYSTICK_CURRENT),
lower->freq);
if (systick_irq_pending(lower))
{
/* Interrupt is pending and the timer wrap happen? */
if (status->timeleft)
{
/* Make timeout-timeleft equal the real elapsed time */
status->timeout += status->timeout - status->timeleft;
status->timeleft = 0;
}
}
else if (status->timeleft == 0)
{
status->timeleft = status->timeout;
}
leave_critical_section(flags);
return 0;
}
static int systick_settimeout(FAR struct timer_lowerhalf_s *lower_,
uint32_t timeout)
{
struct systick_lowerhalf_s *lower = (struct systick_lowerhalf_s *)lower_;
irqstate_t flags = enter_critical_section();
if (lower->next_interval)
{
/* If the timer callback is in the process,
* delay the update to timer interrupt handler.
*/
*lower->next_interval = timeout;
}
else
{
uint32_t reload;
reload = usec_to_count(timeout, lower->freq);
putreg32(reload, NVIC_SYSTICK_RELOAD);
if (systick_is_running())
{
if (reload != getreg32(NVIC_SYSTICK_CURRENT))
{
putreg32(0, NVIC_SYSTICK_CURRENT);
}
}
}
leave_critical_section(flags);
return 0;
}
static void systick_setcallback(FAR struct timer_lowerhalf_s *lower_,
CODE tccb_t callback, FAR void *arg)
{
struct systick_lowerhalf_s *lower = (struct systick_lowerhalf_s *)lower_;
irqstate_t flags = enter_critical_section();
lower->callback = callback;
lower->arg = arg;
leave_critical_section(flags);
}
static int systick_maxtimeout(FAR struct timer_lowerhalf_s *lower_,
uint32_t *maxtimeout)
{
uint64_t maxtimeout64 = usec_from_count(
NVIC_SYSTICK_RELOAD_MASK, g_systick_lower.freq);
if (maxtimeout64 > UINT32_MAX)
{
*maxtimeout = UINT32_MAX;
}
else
{
*maxtimeout = maxtimeout64;
}
return 0;
}
static int systick_interrupt(int irq, FAR void *context, FAR void *arg)
{
struct systick_lowerhalf_s *lower = arg;
if (lower->callback && systick_is_running())
{
uint32_t reload = getreg32(NVIC_SYSTICK_RELOAD);
uint32_t interval = usec_from_count(reload, lower->freq);
uint32_t next_interval = interval;
lower->next_interval = &next_interval;
if (lower->callback(&next_interval, lower->arg))
{
if (next_interval && next_interval != interval)
{
reload = usec_to_count(next_interval, lower->freq);
putreg32(reload, NVIC_SYSTICK_RELOAD);
putreg32(0, NVIC_SYSTICK_CURRENT);
}
}
else
{
modifyreg32(NVIC_SYSTICK_CTRL, NVIC_SYSTICK_CTRL_ENABLE, 0);
}
lower->next_interval = NULL;
}
return 0;
}
/****************************************************************************
* Public Functions
****************************************************************************/
struct timer_lowerhalf_s *systick_initialize(bool coreclk,
unsigned int freq, int minor)
{
struct systick_lowerhalf_s *lower = (struct systick_lowerhalf_s *)&g_systick_lower;
/* Calculate the working clock frequency if need */
if (freq == 0)
{
uint32_t calib = getreg32(NVIC_SYSTICK_CALIB);
uint32_t tenms = calib & NVIC_SYSTICK_CALIB_TENMS_MASK;
lower->freq = 100 * (tenms + 1);
}
else
{
lower->freq = freq;
}
/* Disable SYSTICK, but enable interrupt */
if (coreclk)
{
putreg32(NVIC_SYSTICK_CTRL_CLKSOURCE | NVIC_SYSTICK_CTRL_TICKINT, NVIC_SYSTICK_CTRL);
}
else
{
putreg32(NVIC_SYSTICK_CTRL_TICKINT, NVIC_SYSTICK_CTRL);
}
irq_attach(NVIC_IRQ_SYSTICK, systick_interrupt, lower);
up_enable_irq(NVIC_IRQ_SYSTICK);
/* Register the timer driver if need */
if (minor >= 0)
{
char devname[32];
sprintf(devname, "/dev/timer%d", minor);
timer_register(devname, (struct timer_lowerhalf_s *)lower);
}
return (struct timer_lowerhalf_s *)lower;
}
#endif /* CONFIG_ARMV7M_SYSTICK */