87 lines
2.1 KiB
C
87 lines
2.1 KiB
C
/*
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* File : board.c
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* This file is part of RT-Thread RTOS
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* COPYRIGHT (C) 2012, RT-Thread Development Team
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*
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.rt-thread.org/license/LICENSE
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*
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* Change Logs:
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* Date Author Notes
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* 2012-11-20 Bernard the first version
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*/
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#include <rthw.h>
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#include <rtthread.h>
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#include <components.h>
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#include "board.h"
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#include <registers/regsarmglobaltimer.h>
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#include <registers/regsepit.h>
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#include <uart/imx_uart.h>
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#include <timer/epit.h>
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#include <core/cortex_a9.h>
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static void rt_hw_timer_isr(int vector, void *param)
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{
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rt_tick_increase();
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epit_get_compare_event(HW_EPIT1);
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}
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int rt_hw_timer_init(void)
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{
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uint32_t freq;
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// The ARM private peripheral clock is half the CPU clock.
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uint32_t periphClock = get_main_clock(CPU_CLK) / 2;
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uint32_t prescaler = (periphClock / 1000000) - 1;
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// Divide down the prescaler until it fits into 8 bits. We add up the number of ticks
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// it takes to equal a microsecond interval.
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while (prescaler > 0xff)
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{
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prescaler /= 2;
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}
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// Make sure the timer is off.
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HW_ARMGLOBALTIMER_CONTROL.B.TIMER_ENABLE = 0;
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// Clear counter.
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HW_ARMGLOBALTIMER_COUNTERn_WR(0, 0);
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HW_ARMGLOBALTIMER_COUNTERn_WR(1, 0);
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// Set prescaler and clear other flags.
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HW_ARMGLOBALTIMER_CONTROL_WR(BF_ARMGLOBALTIMER_CONTROL_PRESCALER(prescaler));
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// Now turn on the timer.
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HW_ARMGLOBALTIMER_CONTROL.B.TIMER_ENABLE = 1;
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freq = get_main_clock(IPG_CLK);
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epit_init(HW_EPIT1, CLKSRC_IPG_CLK, freq / 1000000,
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SET_AND_FORGET, 10000, WAIT_MODE_EN | STOP_MODE_EN);
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epit_counter_enable(HW_EPIT1, 10000, IRQ_MODE);
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rt_hw_interrupt_install(IMX_INT_EPIT1, rt_hw_timer_isr, RT_NULL, "tick");
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rt_hw_interrupt_umask(IMX_INT_EPIT1);
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return 0;
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}
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INIT_BOARD_EXPORT(rt_hw_timer_init);
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/**
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* This function will initialize beaglebone board
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*/
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void rt_hw_board_init(void)
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{
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enable_neon_fpu();
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disable_strict_align_check();
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rt_components_board_init();
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rt_console_set_device(RT_CONSOLE_DEVICE_NAME);
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}
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/*@}*/
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