mirror of https://github.com/akuker/RASCSI.git
148 lines
3.9 KiB
C++
148 lines
3.9 KiB
C++
//---------------------------------------------------------------------------
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//
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// SCSI Target Emulator PiSCSI
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// for Raspberry Pi
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//
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// Powered by XM6 TypeG Technology.
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// Copyright (C) 2016-2020 GIMONS
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// Copyright (C) 2022 akuker
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//
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// [ High resolution timer ]
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//
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//---------------------------------------------------------------------------
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#include "hal/systimer_raspberry.h"
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#include <memory>
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#include <sys/ioctl.h>
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#include <sys/mman.h>
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#include "hal/gpiobus.h"
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#include "hal/sbc_version.h"
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#include "shared/log.h"
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// System timer address
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volatile uint32_t *SysTimer_Raspberry::systaddr = nullptr;
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// ARM timer address
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volatile uint32_t *SysTimer_Raspberry::armtaddr = nullptr;
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volatile uint32_t SysTimer_Raspberry::corefreq = 0;
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//---------------------------------------------------------------------------
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//
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// Initialize the system timer
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//
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//---------------------------------------------------------------------------
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void SysTimer_Raspberry::Init()
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{
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// Get the base address
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auto baseaddr = SBC_Version::GetPeripheralAddress();
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// Open /dev/mem
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int mem_fd = open("/dev/mem", O_RDWR | O_SYNC);
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if (mem_fd == -1) {
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LOGERROR("Error: Unable to open /dev/mem. Are you running as root?")
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return;
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}
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// Map peripheral region memory
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void *map = mmap(nullptr, 0x1000100, PROT_READ | PROT_WRITE, MAP_SHARED, mem_fd, baseaddr);
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if (map == MAP_FAILED) {
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LOGERROR("Error: Unable to map memory")
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close(mem_fd);
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return;
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}
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close(mem_fd);
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// RPI Mailbox property interface
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// Get max clock rate
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// Tag: 0x00030004
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//
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// Request: Length: 4
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// Value: u32: clock id
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// Response: Length: 8
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// Value: u32: clock id, u32: rate (in Hz)
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//
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// Clock id
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// 0x000000004: CORE
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std::array<uint32_t, 32> maxclock = {32, 0, 0x00030004, 8, 0, 4, 0, 0};
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// Save the base address
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systaddr = (uint32_t *)map + SYST_OFFSET / sizeof(uint32_t);
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armtaddr = (uint32_t *)map + ARMT_OFFSET / sizeof(uint32_t);
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// Change the ARM timer to free run mode
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armtaddr[ARMT_CTRL] = 0x00000282;
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// Get the core frequency
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if (int vcio_fd = open("/dev/vcio", O_RDONLY); vcio_fd >= 0) {
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ioctl(vcio_fd, _IOWR(100, 0, char *), maxclock.data());
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corefreq = maxclock[6] / 1000000;
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close(vcio_fd);
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}
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}
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//---------------------------------------------------------------------------
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//
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// Get system timer low byte
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//
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//---------------------------------------------------------------------------
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uint32_t SysTimer_Raspberry::GetTimerLow()
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{
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return systaddr[SYST_CLO];
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}
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//---------------------------------------------------------------------------
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//
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// Get system timer high byte
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//
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//---------------------------------------------------------------------------
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uint32_t SysTimer_Raspberry::GetTimerHigh()
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{
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return systaddr[SYST_CHI];
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}
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//---------------------------------------------------------------------------
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//
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// Sleep in nanoseconds
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//
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//---------------------------------------------------------------------------
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void SysTimer_Raspberry::SleepNsec(uint32_t nsec)
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{
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// If time is 0, don't do anything
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if (nsec == 0) {
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return;
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}
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// Calculate the timer difference
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uint32_t diff = corefreq * nsec / 1000;
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// Return if the difference in time is too small
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if (diff == 0) {
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return;
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}
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// Start
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uint32_t start = armtaddr[ARMT_FREERUN];
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// Loop until timer has elapsed
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while ((armtaddr[ARMT_FREERUN] - start) < diff)
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;
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}
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//---------------------------------------------------------------------------
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//
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// Sleep in microseconds
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//
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//---------------------------------------------------------------------------
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void SysTimer_Raspberry::SleepUsec(uint32_t usec)
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{
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// If time is 0, don't do anything
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if (usec == 0) {
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return;
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}
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uint32_t now = GetTimerLow();
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while ((GetTimerLow() - now) < usec)
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;
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}
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