190 lines
5.7 KiB
C
190 lines
5.7 KiB
C
/****************************************************************************
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* arch/arm/src/tms570/tms570_timerisr.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <nuttx/arch.h>
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#include "arm_internal.h"
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#include "arm_arch.h"
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#include "hardware/tms570_rti.h"
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#include <arch/board/board.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* The input clock to the RTI is the RTICLK. The RTI source is always VCLK
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* which may be divided down by 2. The correct RTICLK frequency must be
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* provided by board.h file as BOARD_RTICLK_FREQUENCY.
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*/
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#ifndef BOARD_RTICLK_FREQUENCY
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# error BOARD_RTICLK_FREQUENCY not defined
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#endif
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/* Timing Calculations:
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*
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* FRC0CLK = RTICLK / (CPUC0 + 1) Hz
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* Tcount = 1 / FRC0CLK Seconds
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* = 1,000,000 / FRC0CLK Microseconds
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* CMP0 = Period / Tcount
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* = CONFIG_USEC_PER_TICK * FRC0CLK / 1,000,000
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* = CONFIG_USEC_PER_TICK * RTICLK / (CPUC0 + 1) / 1,000,000
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*
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* For Example:
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* VCLK = 80,000,000 Hz
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* RTICLK = VCLK / 2 Hz
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* = 40,000,000 Hz
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* CPUC0 = 39
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* FR0CLK = 1,000,000 Hz
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* Tcount = 1 Microsecond
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* CONFIG_USEC_PER_TICK = 10,000 Microseconds
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* CMP0 = 10,000 * 40,000,000 / 40 / 1,000,000
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* = 10, 000 = CONFIG_USEC_PER_TICK
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*/
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#if BOARD_RTICLK_FREQUENCY > 10000000
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/* Use FR0CLK = 1MHz with CPUC0 at least 9 */
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# define RTI_FRC0CLK (1000000)
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#elif BOARD_RTICLK_FREQUENCY > 5000000
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/* Use FR0CLK = 500KHz with CPUC0 at least 9 */
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# define RTI_FRC0CLK (500000)
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#elif BOARD_RTICLK_FREQUENCY > 1000000
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/* Use FR0CLK = 100KHz with CPUC0 at least 9 */
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# define RTI_FRC0CLK (100000)
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#else
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# error No logic for this value of RTICLK
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#endif
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/* CPUC0 = RTICLK / FRC0CLK - 1
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*
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* NOTES:
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* - The following calculation performs rounding.
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*/
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#define RTI_CPUC0 (((BOARD_RTICLK_FREQUENCY ) / RTI_FRC0CLK) - 1)
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/* CMP0 = CONFIG_USEC_PER_TICK * FRC0CLK / 1,000,000
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*
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* NOTES:
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* - The following calculation performs rounding.
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* - The following calculation avoids integer overflow by depending on
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* FRCLK being a multiple of 100,000
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*/
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#define RTI_CMP0 ((CONFIG_USEC_PER_TICK * (RTI_FRC0CLK / 100000) + 50) / 10)
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: tms570_timerisr
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*
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* Description:
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* The timer ISR will perform a variety of services for various portions
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* of the systems.
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*
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****************************************************************************/
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static int tms570_timerisr(int irq, uint32_t *regs, void *arg)
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{
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/* Clear the RTI Compare 0 interrupts */
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putreg32(RTI_INT0, TMS570_RTI_INTFLAG);
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/* Process timer interrupt */
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nxsched_process_timer();
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return 0;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: up_timer_initialize
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*
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* Description:
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* This function is called during start-up to initialize the timer
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* interrupt.
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*
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****************************************************************************/
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void up_timer_initialize(void)
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{
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/* Disable all RTI interrupts */
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up_disable_irq(TMS570_REQ_RTICMP0);
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putreg32(0x0, TMS570_RTI_GCTRL);
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putreg32(RTI_ALLINTS, TMS570_RTI_CLEARINTENA);
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/* Configure RTICOMP0 register and the RTIUDCP0 Register to initialize with
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* the calculated compare value.
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*/
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putreg32(RTI_CMP0, TMS570_RTI_COMP0);
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putreg32(RTI_CMP0, TMS570_RTI_UDCP0);
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/* Configure the FRC0CLK clock by setting the RTICPUC0 register to the
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* calculated value.
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*/
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putreg32(RTI_CPUC0, TMS570_RTI_CPUC0);
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/* Initialize the free-running counter and the RTI up-counter */
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putreg32(0, TMS570_RTI_FRC0);
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putreg32(0, TMS570_RTI_UC0);
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/* Clear any pending interrupts */
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putreg32(RTI_ALLINTS, TMS570_RTI_INTFLAG);
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/* Enable the RTI Compare 0 interrupts (still disabled at the VIM) */
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putreg32(RTI_INT0, TMS570_RTI_SETINTENA);
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/* Enable counter 0 */
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putreg32(RTI_GCTRL_CNT0EN, TMS570_RTI_GCTRL);
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/* Attach the interrupt handler to the RTI Compare 0 interrupt */
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DEBUGVERIFY(irq_attach(TMS570_REQ_RTICMP0, (xcpt_t)tms570_timerisr, NULL));
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/* Enable RTI compare 0 interrupts at the VIM */
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up_enable_irq(TMS570_REQ_RTICMP0);
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}
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