97 lines
2.8 KiB
C
97 lines
2.8 KiB
C
/******************************************************************************
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*
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* Copyright (c) 2017-2019 by Löwenware Ltd
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* Please, refer LICENSE file for legal information
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*
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******************************************************************************/
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/**
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* @file timer.c
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* @author Ilja Kartašov <ik@lowenware.com>
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* @brief
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*
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* @see https://lowenware.com/
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*/
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#include <aarch64/aarch64.h>
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#include <drivers/soc/bcm2837/bcm2837.h>
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#include <leos/log.h>
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#include "timer.h"
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const unsigned int m_interval = 2000000;
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unsigned int m_current = 0;
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#ifndef CONFIG_ARM_TIMER
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#define CONFIG_ARM_TIMER 1
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#endif
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#define TIMER_ENABLE ((1 << 31) | (1 << 29) | (1 << 28))
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#define TIMER_RELOAD 1
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/*
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* https://www.raspberrypi.org/forums/viewtopic.php?t=213393
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* The sequence on a real PI3 is
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* 1.) Route the local timer to a core register 0x40000024 (bits 0..2)
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* QA7_rev3.4.pdf page 18 ... say write 0 which is core 0
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*
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* 2.) Setup timer status control register 0x40000034 (all 32 bits)
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* QA7_rev3.4.pdf page 17 ... reload value 5000000 = like half sec, enable clock, enable interrupt
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* You can play with clock prescalers etc later.
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* 3.) Hit timer interrupt clear and reload register 0x40000038 (bits 30 & 31)
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* QA7_rev3.4.pdf page 18 ... write 1 to both bits which clears irq signal and loads value from above
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*
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* 4.) Setup timer interrupt control register 0x40000040 (all bits ... zero all but the one bit set)
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* QA7_rev3.4.pdf page 13 ... now this depends what mode Core0 leaves your bootstub in.
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* If you did no EL changes in stub the core0 will still be in Hyp mode if like me you dropped it to SVC mode it is Non Secure
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*
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* If Core0 enters in Hyp mode ... set nCNTHPIRQ_IRQ bit 1
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* If Core0 enters in Svc mode ... set nCNTPNSIRQ_IRQ bit 2
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*
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* 5.) Now you need to enable global interupts
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* asm(" cpsie i")
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* */
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void
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Timer_init(void)
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{
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#if CONFIG_ARM_TIMER == 1
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/* Route local timer to a core0 */
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AARCH64_LOCAL_INT_ROUTING &= ~0x03;
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/* Set up timer status control register */
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AARCH64_LOCAL_TIMER_STATCTL = TIMER_ENABLE | TIMER_RELOAD;
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/* clear interrupt flag and reload timer */
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AARCH64_LOCAL_TIMER_RECLR |= (1 << 31) | (1 << 30);
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/* Set timer interrupt control register */
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AARCH64_CORE0_TIMER_IRQCTL = (1 << 1); /* nCNTPNSIR1 - Non Secure*/
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#else
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m_current = aarch64_get32r(TIMER_CLO);
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m_current += m_interval;
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aarch64_set32r(TIMER_C1, m_current);
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#endif
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}
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void
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Timer_incFromISR(void)
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{
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m_current++; /*= m_interval;*/
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#if CONFIG_ARM_TIMER == 1
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/* clear interrupt flag and reload timer */
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AARCH64_LOCAL_TIMER_RECLR |= (1 << 31) | (1 << 30);
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#else
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aarch64_set32r(TIMER_C1, m_current);
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aarch64_set32r(TIMER_CS, TIMER_CS_M1);
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#endif
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/*
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Log_putS("--- tick --- ");
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Log_putI(m_current, 10);
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Log_putS(" ---\r\n");
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*/
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}
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uint32_t
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Timer_getTicks(void)
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{
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return m_current;
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}
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