137 lines
4.6 KiB
C
137 lines
4.6 KiB
C
/****************************************************************************
|
|
* arch/sparc/src/bm3803/bm3803-timerisr.c
|
|
*
|
|
* Licensed to the Apache Software Foundation (ASF) under one or more
|
|
* contributor license agreements. See the NOTICE file distributed with
|
|
* this work for additional information regarding copyright ownership. The
|
|
* ASF licenses this file to you under the Apache License, Version 2.0 (the
|
|
* "License"); you may not use this file except in compliance with the
|
|
* License. You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
|
|
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
|
|
* License for the specific language governing permissions and limitations
|
|
* under the License.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <stdint.h>
|
|
#include <time.h>
|
|
#include <debug.h>
|
|
|
|
#include <nuttx/arch.h>
|
|
#include <arch/board/board.h>
|
|
|
|
#include "sparc_internal.h"
|
|
#include "bm3803.h"
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
/* The CPU frequency is given by BOARD_CPU_CLOCK (defined in board.h). The
|
|
* desired interrupt frequency is given by CONFIG_USEC_PER_TICK. An unscaled
|
|
* ideal match is given by:
|
|
*
|
|
* CLOCK = CPU_CLOCK / DIVISOR # CPU clocks/sec
|
|
* MATCH = CLOCK / CLOCKS_PER_SEC # CPU clocks/timer tick
|
|
* MATCH = CPU_CLOCK / DIVISOR / CLOCKS_PER_SEC # CPU clocks/timer tick
|
|
*
|
|
* But we only have 16-bits of accuracy so we need to pick the smallest
|
|
* divisor using the following brute force calculation:
|
|
*/
|
|
#define BM3803_TIMER_CLOCK 1000000
|
|
#define MATCH1 (( 1000000 / CLOCKS_PER_SEC) - 1)
|
|
|
|
/* Bit 0: enables the timer when set */
|
|
#define TIMCTR_ENABLE_COUNTER (1 << 0)
|
|
|
|
/* Bit 1: automatically reloaded with the reload value after each underflow */
|
|
#define TIMCTR_AUTO_RELOAD (1 << 1)
|
|
|
|
/* Bit 2: Set 1, will load the timer reload register into the timer counter
|
|
* register
|
|
*/
|
|
|
|
#define TIMCTR_LOAD_COUNTER (1 << 2)
|
|
|
|
/****************************************************************************
|
|
* Private Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Function: bm3803_timerisr
|
|
*
|
|
* Description:
|
|
* The timer ISR will perform a variety of services for various portions
|
|
* of the systems.
|
|
*
|
|
****************************************************************************/
|
|
|
|
static int bm3803_timerisr(int irq, uint32_t *regs, void *arg)
|
|
{
|
|
/* Clear the pending timer interrupt */
|
|
|
|
sparc_clrpend_irq(BM3803_IRQ_TIMER1);
|
|
|
|
/* Process timer interrupt */
|
|
|
|
nxsched_process_timer();
|
|
return 0;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Function: up_timer_initialize
|
|
*
|
|
* Description:
|
|
* This function is called during start-up to initialize the timer
|
|
* interrupt. NOTE: This function depends on setup of OSC32 by
|
|
* up_clkinitialize().
|
|
*
|
|
****************************************************************************/
|
|
|
|
void up_timer_initialize(void)
|
|
{
|
|
BM3803_REG.scaler_load = (BOARD_CPU_CLOCK / BM3803_TIMER_CLOCK) - 1;
|
|
BM3803_REG.scaler_cnt = (BOARD_CPU_CLOCK / BM3803_TIMER_CLOCK) - 1;
|
|
|
|
/* Setup timer 1 compare match A to generate a tick interrupt.
|
|
*
|
|
* First, setup the match value for compare match A.
|
|
*/
|
|
|
|
BM3803_REG.timer_cnt1 = (uint32_t)MATCH1;
|
|
BM3803_REG.timer_load1 = (uint32_t)MATCH1;
|
|
|
|
BM3803_REG.timer_ctrl1 = (TIMCTR_ENABLE_COUNTER | TIMCTR_AUTO_RELOAD |
|
|
TIMCTR_LOAD_COUNTER);
|
|
|
|
/* Configure the timer interrupt */
|
|
|
|
sparc_clrpend_irq(BM3803_IRQ_TIMER1);
|
|
#ifdef CONFIG_ARCH_IRQPRIO
|
|
up_prioritize_irq(BM3803_IRQ_TIMER1, CONFIG_BM3803_TIMER1PRIO);
|
|
#endif
|
|
|
|
/* Attach the timer interrupt vector */
|
|
|
|
irq_attach(BM3803_IRQ_TIMER1, (xcpt_t)bm3803_timerisr, NULL);
|
|
|
|
/* And enable the timer interrupt */
|
|
|
|
up_enable_irq(BM3803_IRQ_TIMER1);
|
|
}
|