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Kernel: Let's say that IO::delay(N) delays for N microseconds

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Supposedly that's how much delay you get when doing I/O on port 0x80.
This commit is contained in:
Andreas Kling 2020-05-16 10:39:06 +02:00
parent 85aafe492d
commit 03eb0e5638
Notes: sideshowbarker 2024-07-19 06:37:13 +09:00 
Author: https://github.com/awesomekling
Commit: https://github.com/SerenityOS/serenity/commit/03eb0e5638b
3 changed files with 5 additions and 11 deletions
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2
Kernel/Devices/SB16.cpp
View file

@ -100,7 +100,7 @@ void SB16::initialize()
disable_irq();
IO::out8(0x226, 1);
IO::delay();
IO::delay(32);
IO::out8(0x226, 0);
auto data = dsp_read();

8
Kernel/Interrupts/APIC.cpp
View file

@ -215,20 +215,16 @@ void enable(u32 cpu)
write_register(APIC_REG_TPR, 0);
if (cpu != 0) {
static volatile u32 foo = 0;
// INIT
write_icr(ICRReg(0, ICRReg::INIT, ICRReg::Physical, ICRReg::Assert, ICRReg::TriggerMode::Edge, ICRReg::AllExcludingSelf));
for (foo = 0; foo < 0x800000; foo++)
; // TODO: 10 millisecond delay
IO::delay(10 * 1000);
for (int i = 0; i < 2; i++) {
// SIPI
write_icr(ICRReg(0x08, ICRReg::StartUp, ICRReg::Physical, ICRReg::Assert, ICRReg::TriggerMode::Edge, ICRReg::AllExcludingSelf)); // start execution at P8000
for (foo = 0; foo < 0x80000; foo++)
; // TODO: 200 microsecond delay
IO::delay(200);
}
}
}

6
Libraries/LibBareMetal/IO.h
View file

@ -94,12 +94,10 @@ inline void repeated_out16(u16 port, const u16* data, int data_size)
: "d"(port));
}
inline void delay()
inline void delay(size_t microseconds)
{
// ~3 microsecs
for (auto i = 0; i < 32; i++) {
for (size_t i = 0; i < microseconds; ++i)
IO::in8(0x80);
}
}
}