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/*
* Copyright (c) 2011-2012, Freescale Semiconductor, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* o Redistributions of source code must retain the above copyright notice, this list
* of conditions and the following disclaimer.
*
* o 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.
*
* o Neither the name of Freescale Semiconductor, Inc. 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 HOLDER 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.
*/
/*!
* @file timer.c
* @brief Basic timer functions
*
* @ingroup diag_timer
*/
#include <assert.h>
#include "imx_timer.h"
#include "sdk.h"
#include "epit.h"
#include "registers/regsarmglobaltimer.h"
#include "ccm_pll.h"
////////////////////////////////////////////////////////////////////////////////
// Prototypes
////////////////////////////////////////////////////////////////////////////////
static void time_init_global_timer();
////////////////////////////////////////////////////////////////////////////////
// Variables
////////////////////////////////////////////////////////////////////////////////
uint32_t g_microsecondTimerMultiple=8;
////////////////////////////////////////////////////////////////////////////////
// Code
////////////////////////////////////////////////////////////////////////////////
void hal_delay_us(uint32_t usecs)
{
uint32_t instance = g_system_timer_port;
if (usecs == 0) {
return;
}
/* enable the counter first */
epit_counter_enable(instance, usecs, POLLING_MODE);
/* wait for the compare event */
while (!epit_get_compare_event(instance)) ;
/* disable the counter to save power */
epit_counter_disable(instance);
}
void system_time_init(void)
{
uint32_t freq;
// Init microsecond tick counter.
time_init_global_timer();
/* EPIT1 is used for the delay function */
/* Initialize the EPIT timer used for system time functions */
/* typical IPG_CLK is in MHz, so divide it to get a reference
clock of 1MHz => 1us per count */
freq = get_main_clock(IPG_CLK);
epit_init(g_system_timer_port, CLKSRC_IPG_CLK, freq / 1000000,
SET_AND_FORGET, 1000, WAIT_MODE_EN | STOP_MODE_EN);
}
#if defined(CHIP_MX6UL)
//! Init the ARM global timer to a microsecond-frequency clock.
void time_init_global_timer()
{
// Make sure the timer is off.
HW_ARMGLOBALTIMER_CONTROL.B.TIMER_ENABLE = 0;
HW_ARMGLOBALTIMER_CONTROL.B.FCR0 =1;
HW_ARMGLOBALTIMER_CONTROL.B.FCR1 =0;
HW_ARMGLOBALTIMER_CONTROL.B.DBG_ENABLE =0;
// Clear counter.
HW_ARMGLOBALTIMER_COUNTER_HI_WR(0);
HW_ARMGLOBALTIMER_COUNTER_LO_WR(0);
// Now turn on the timer.
HW_ARMGLOBALTIMER_CONTROL.B.TIMER_ENABLE = 1;
}
uint64_t time_get_microseconds()
{
// First read upper.
uint32_t upper = HW_ARMGLOBALTIMER_COUNTER_HI_RD();
uint32_t lower = HW_ARMGLOBALTIMER_COUNTER_LO_RD();
return (((uint64_t)upper << 32) | (uint64_t)lower)/8;
}
#else
//! Init the ARM global timer to a microsecond-frequency clock.
void time_init_global_timer()
{
// The ARM private peripheral clock is half the CPU clock.
uint32_t periphClock = get_main_clock(CPU_CLK) / 2;
uint32_t prescaler = (periphClock / 1000000) - 1;
// Divide down the prescaler until it fits into 8 bits. We add up the number of ticks
// it takes to equal a microsecond interval.
g_microsecondTimerMultiple = 1;
while (prescaler > 0xff)
{
prescaler /= 2;
++g_microsecondTimerMultiple;
}
// Make sure the timer is off.
HW_ARMGLOBALTIMER_CONTROL.B.TIMER_ENABLE = 0;
// Clear counter.
HW_ARMGLOBALTIMER_COUNTERn_WR(0, 0);
HW_ARMGLOBALTIMER_COUNTERn_WR(1, 0);
// Set prescaler and clear other flags.
HW_ARMGLOBALTIMER_CONTROL_WR(BF_ARMGLOBALTIMER_CONTROL_PRESCALER(prescaler));
// Now turn on the timer.
HW_ARMGLOBALTIMER_CONTROL.B.TIMER_ENABLE = 1;
}
uint64_t time_get_microseconds()
{
// First read upper.
uint32_t upper = HW_ARMGLOBALTIMER_COUNTERn_RD(1);
uint32_t lower;
while (true)
{
// Read lower.
lower = HW_ARMGLOBALTIMER_COUNTERn_RD(0);
// Read upper again.
uint32_t newUpper = HW_ARMGLOBALTIMER_COUNTERn_RD(1);
// If the first and second read of the upper bits are the same, then return.
if (newUpper == upper)
{
return (((uint64_t)upper << 32) | (uint64_t)lower) / g_microsecondTimerMultiple;
}
// Otherwise, start over again.
upper = newUpper;
}
return 0;
}
#endif
////////////////////////////////////////////////////////////////////////////////
// EOF
////////////////////////////////////////////////////////////////////////////////
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