RASCSI/cpp/hal/systimer.cpp

141 lines
3.5 KiB
C++

//---------------------------------------------------------------------------
//
// SCSI Target Emulator RaSCSI Reloaded
// for Raspberry Pi
//
// Powered by XM6 TypeG Technology.
// Copyright (C) 2016-2020 GIMONS
// Copyright (C) 2022 akuker
//
// [ High resolution timer ]
//
//---------------------------------------------------------------------------
#include "hal/systimer.h"
#include "hal/gpiobus.h"
#include "shared/config.h"
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <array>
//---------------------------------------------------------------------------
//
// System timer address
//
//---------------------------------------------------------------------------
volatile uint32_t* SysTimer::systaddr;
//---------------------------------------------------------------------------
//
// ARM timer address
//
//---------------------------------------------------------------------------
volatile uint32_t* SysTimer::armtaddr;
//---------------------------------------------------------------------------
//
// Core frequency
//
//---------------------------------------------------------------------------
volatile uint32_t SysTimer::corefreq;
//---------------------------------------------------------------------------
//
// Initialize the system timer
//
//---------------------------------------------------------------------------
void SysTimer::Init(uint32_t *syst, uint32_t *armt)
{
// RPI Mailbox property interface
// Get max clock rate
// Tag: 0x00030004
//
// Request: Length: 4
// Value: u32: clock id
// Response: Length: 8
// Value: u32: clock id, u32: rate (in Hz)
//
// Clock id
// 0x000000004: CORE
array<uint32_t, 32> maxclock = { 32, 0, 0x00030004, 8, 0, 4, 0, 0 };
// Save the base address
systaddr = syst;
armtaddr = armt;
// Change the ARM timer to free run mode
armtaddr[ARMT_CTRL] = 0x00000282;
// Get the core frequency
corefreq = 0;
int fd = open("/dev/vcio", O_RDONLY);
if (fd >= 0) {
ioctl(fd, _IOWR(100, 0, char *), maxclock);
corefreq = maxclock[6] / 1000000;
}
close(fd);
}
//---------------------------------------------------------------------------
//
// Get system timer low byte
//
//---------------------------------------------------------------------------
uint32_t SysTimer::GetTimerLow() {
return systaddr[SYST_CLO];
}
//---------------------------------------------------------------------------
//
// Get system timer high byte
//
//---------------------------------------------------------------------------
uint32_t SysTimer::GetTimerHigh() {
return systaddr[SYST_CHI];
}
//---------------------------------------------------------------------------
//
// Sleep in nanoseconds
//
//---------------------------------------------------------------------------
void SysTimer::SleepNsec(uint32_t nsec)
{
// If time is 0, don't do anything
if (nsec == 0) {
return;
}
// Calculate the timer difference
uint32_t diff = corefreq * nsec / 1000;
// Return if the difference in time is too small
if (diff == 0) {
return;
}
// Start
uint32_t start = armtaddr[ARMT_FREERUN];
// Loop until timer has elapsed
while ((armtaddr[ARMT_FREERUN] - start) < diff);
}
//---------------------------------------------------------------------------
//
// Sleep in microseconds
//
//---------------------------------------------------------------------------
void SysTimer::SleepUsec(uint32_t usec)
{
// If time is 0, don't do anything
if (usec == 0) {
return;
}
uint32_t now = GetTimerLow();
while ((GetTimerLow() - now) < usec);
}