157 lines
5.1 KiB
C
157 lines
5.1 KiB
C
/****************************************************************************
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* arch/sparc/src/s698pm/s698pm-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 <time.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include <arch/board/board.h>
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#include "sparc_internal.h"
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#include "s698pm.h"
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#include "s698pm_tim.h"
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#include "s698pm_irq.h"
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* The CPU frequency is given by BOARD_CPU_CLOCK (defined in board.h). The
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* desired interrupt frequency is given by CONFIG_USEC_PER_TICK. An unscaled
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* ideal match is given by:
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*
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* CLOCK = CPU_CLOCK / DIVISOR # CPU clocks/sec
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* MATCH = CLOCK / CLOCKS_PER_SEC # CPU clocks/timer tick
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* MATCH = CPU_CLOCK / DIVISOR / CLOCKS_PER_SEC # CPU clocks/timer tick
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*
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* But we only have 16-bits of accuracy so we need to pick the smallest
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* divisor using the following brute force calculation:
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*/
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#define S698PM_TIMER_CLOCK 1000000
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#define MATCH1 (( 1000000 / CLOCKS_PER_SEC) - 1)
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/* Bit 0: enables the timer when set */
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#define TIMCTR_ENABLE_COUNTER (1 << 0)
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/* Bit 1: automatically reloaded with the reload value after each underflow */
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#define TIMCTR_AUTO_RELOAD (1 << 1)
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/* Bit 2: Set 1, will load the timer reload register into the timer counter
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* register
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*/
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#define TIMCTR_LOAD_COUNTER (1 << 2)
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/* Bit 3: Set 1, will triger underflow interrupt each underflow */
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#define TIMCTR_ENABLE_INT (1 << 3)
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Function: s698pm_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 s698pm_timerisr(int irq, uint32_t *regs, void *arg)
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{
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/* Clear the pending timer interrupt */
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sparc_clrpend_irq(S698PM_IRQ_TIMER1);
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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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* Function: 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. NOTE: This function depends on setup of OSC32 by
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* up_clkinitialize().
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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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uint32_t regval;
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regval = (BOARD_CPU_CLOCK / S698PM_TIMER_CLOCK) - 1;
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putreg16(regval, S698PM_TIMPRE_BASE + S698PM_TIM_PSCLOAD_OFFSET);
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putreg16(regval, S698PM_TIMPRE_BASE + S698PM_TIM_PSCCONT_OFFSET);
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/* Setup timer 1 compare match A to generate a tick interrupt.
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*
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* First, setup the match value for compare match A.
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*/
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putreg32(MATCH1, S698PM_TIM1_BASE + S698PM_TIM_CNT_OFFSET);
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putreg32(MATCH1, S698PM_TIM1_BASE + S698PM_TIM_ARR_OFFSET);
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regval = (TIMCTR_ENABLE_COUNTER | TIMCTR_AUTO_RELOAD |
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TIMCTR_LOAD_COUNTER | TIMCTR_ENABLE_INT);
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putreg32(regval, S698PM_TIM1_BASE + S698PM_TIM_CR_OFFSET);
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/* Configure the timer interrupt */
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sparc_clrpend_irq(S698PM_IRQ_TIMER1);
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/* Attach the timer interrupt vector */
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irq_attach(S698PM_IRQ_TIMER1, (xcpt_t)s698pm_timerisr, NULL);
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/* Set up to timer1 interrupts on the current CPU */
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#ifdef CONFIG_ARCH_IRQPRIO
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(void)s698pm_setup_irq(0, S698PM_IRQ_TIMER1, CONFIG_S698PM_TIMER1PRIO);
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#else
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(void)s698pm_setup_irq(0, S698PM_IRQ_TIMER1, 0);
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#endif
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/* And enable the timer interrupt */
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up_enable_irq(S698PM_IRQ_TIMER1);
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}
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