129 lines
4.2 KiB
C
129 lines
4.2 KiB
C
/************************************************************
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* c5471/c5471_timerisr.c
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*
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* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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************************************************************/
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/************************************************************
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* Included Files
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************************************************************/
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#include <nuttx/config.h>
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#include <stdint.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include "chip.h"
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#include "up_arch.h"
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#include "clock_internal.h"
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#include "up_internal.h"
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/************************************************************
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* Pre-processor Definitions
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************************************************************/
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/* We want the general purpose timer running at the rate
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* MSEC_PER_TICK. The C5471 clock is 47.5MHz and we're using
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* a timer PTV value of 3 (3 == divide incoming frequency by
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* 16) which then yields a 16 bitCLKS_PER_INT value
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* of 29687.
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*
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* 47500000 / 16 = 2968750 clocks/sec
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* 2968750 / 100 = 29687 clocks/ 100Hz interrupt
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*
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*/
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#define CLKS_PER_INT 29687
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#define CLKS_PER_INT_SHIFT 5
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#define AR 0x00000010
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#define ST 0x00000008
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#define PTV 0x00000003
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/************************************************************
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* Private Types
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************************************************************/
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/************************************************************
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* Private Function Prototypes
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************************************************************/
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/************************************************************
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* Global Functions
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************************************************************/
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/************************************************************
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* Function: up_timerisr
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*
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* Description:
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* The timer ISR will perform a variety of services for
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* various portions of the systems.
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*
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************************************************************/
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int up_timerisr(int irq, uint32_t *regs)
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{
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/* Process timer interrupt */
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sched_process_timer();
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return 0;
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}
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/************************************************************
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* Function: up_timerinit
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*
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* Description:
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* This function is called during start-up to initialize
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* the timer interrupt.
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*
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************************************************************/
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void up_timerinit(void)
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{
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uint32_t val;
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up_disable_irq(C5471_IRQ_SYSTIMER);
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/* Start the general purpose timer running in auto-reload mode
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* so that an interrupt is generated at the rate MSEC_PER_TICK.
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*/
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val = ((CLKS_PER_INT-1) << CLKS_PER_INT_SHIFT) | AR | ST | PTV;
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putreg32(val, C5471_TIMER2_CTRL);
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/* Attach and enable the timer interrupt */
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irq_attach(C5471_IRQ_SYSTIMER, (xcpt_t)up_timerisr);
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up_enable_irq(C5471_IRQ_SYSTIMER);
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}
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