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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/Types.h>
#include <Kernel/Arch/x86/InterruptDisabler.h>
#include <Kernel/IO.h>
#include <Kernel/Interrupts/GenericInterruptHandler.h>
#include <Kernel/Interrupts/PIC.h>
#include <Kernel/Sections.h>
namespace Kernel {
// The slave 8259 is connected to the master's IRQ2 line.
// This is really only to enhance clarity.
#define SLAVE_INDEX 2
#define PIC0_CTL 0x20
#define PIC0_CMD 0x21
#define PIC1_CTL 0xA0
#define PIC1_CMD 0xA1
#define ICW1_ICW4 0x01 // ICW4 (not) needed
#define ICW1_SINGLE 0x02 // Single (cascade) mode
#define ICW1_INTERVAL4 0x04 // Call address interval 4 (8)
#define ICW1_LEVEL 0x08 // Level triggered (edge) mode
#define ICW1_INIT 0x10 // Initialization - required
#define ICW4_8086 0x01 // 8086/88 (MCS-80/85) mode
#define ICW4_AUTO 0x02 // Auto (normal) EOI
#define ICW4_BUF_SLAVE 0x08 // Buffered mode/slave
#define ICW4_BUF_MASTER 0x0C // Buffered mode/master
#define ICW4_SFNM 0x10 // Special fully nested (not)
bool inline static is_all_masked(u16 reg)
{
return reg == 0xFFFF;
}
bool PIC::is_enabled() const
{
return !is_all_masked(m_cached_irq_mask) && !is_hard_disabled();
}
void PIC::disable(const GenericInterruptHandler& handler)
{
InterruptDisabler disabler;
VERIFY(!is_hard_disabled());
VERIFY(handler.interrupt_number() >= gsi_base() && handler.interrupt_number() < interrupt_vectors_count());
u8 irq = handler.interrupt_number();
if (m_cached_irq_mask & (1 << irq))
return;
u8 imr;
if (irq & 8) {
imr = IO::in8(PIC1_CMD);
imr |= 1 << (irq & 7);
IO::out8(PIC1_CMD, imr);
} else {
imr = IO::in8(PIC0_CMD);
imr |= 1 << irq;
IO::out8(PIC0_CMD, imr);
}
m_cached_irq_mask |= 1 << irq;
}
UNMAP_AFTER_INIT PIC::PIC()
{
initialize();
}
void PIC::spurious_eoi(const GenericInterruptHandler& handler) const
{
VERIFY(handler.type() == HandlerType::SpuriousInterruptHandler);
if (handler.interrupt_number() == 7)
return;
if (handler.interrupt_number() == 15) {
IO::in8(PIC1_CMD); /* dummy read */
IO::out8(PIC0_CTL, 0x60 | (2));
}
}
bool PIC::is_vector_enabled(u8 irq) const
{
return m_cached_irq_mask & (1 << irq);
}
void PIC::enable(const GenericInterruptHandler& handler)
{
InterruptDisabler disabler;
VERIFY(!is_hard_disabled());
VERIFY(handler.interrupt_number() >= gsi_base() && handler.interrupt_number() < interrupt_vectors_count());
enable_vector(handler.interrupt_number());
}
void PIC::enable_vector(u8 irq)
{
InterruptDisabler disabler;
VERIFY(!is_hard_disabled());
if (!(m_cached_irq_mask & (1 << irq)))
return;
u8 imr;
if (irq & 8) {
imr = IO::in8(PIC1_CMD);
imr &= ~(1 << (irq & 7));
IO::out8(PIC1_CMD, imr);
} else {
imr = IO::in8(PIC0_CMD);
imr &= ~(1 << irq);
IO::out8(PIC0_CMD, imr);
}
m_cached_irq_mask &= ~(1 << irq);
}
void PIC::eoi(const GenericInterruptHandler& handler) const
{
InterruptDisabler disabler;
VERIFY(!is_hard_disabled());
u8 irq = handler.interrupt_number();
VERIFY(irq >= gsi_base() && irq < interrupt_vectors_count());
if ((1 << irq) & m_cached_irq_mask) {
spurious_eoi(handler);
return;
}
eoi_interrupt(irq);
}
void PIC::eoi_interrupt(u8 irq) const
{
if (irq & 8) {
IO::in8(PIC1_CMD); /* dummy read */
IO::out8(PIC1_CTL, 0x60 | (irq & 7));
IO::out8(PIC0_CTL, 0x60 | (2));
return;
}
IO::in8(PIC0_CMD); /* dummy read */
IO::out8(PIC0_CTL, 0x60 | irq);
}
void PIC::complete_eoi() const
{
IO::out8(PIC1_CTL, 0x20);
IO::out8(PIC0_CTL, 0x20);
}
void PIC::hard_disable()
{
InterruptDisabler disabler;
remap(0x20);
IO::out8(PIC0_CMD, 0xff);
IO::out8(PIC1_CMD, 0xff);
m_cached_irq_mask = 0xffff;
IRQController::hard_disable();
}
void PIC::remap(u8 offset)
{
/* ICW1 (edge triggered mode, cascading controllers, expect ICW4) */
IO::out8(PIC0_CTL, ICW1_INIT | ICW1_ICW4);
IO::out8(PIC1_CTL, ICW1_INIT | ICW1_ICW4);
/* ICW2 (upper 5 bits specify ISR indices, lower 3 idunno) */
IO::out8(PIC0_CMD, offset);
IO::out8(PIC1_CMD, offset + 0x08);
/* ICW3 (configure master/slave relationship) */
IO::out8(PIC0_CMD, 1 << SLAVE_INDEX);
IO::out8(PIC1_CMD, SLAVE_INDEX);
/* ICW4 (set x86 mode) */
IO::out8(PIC0_CMD, ICW4_8086);
IO::out8(PIC1_CMD, ICW4_8086);
// Mask -- start out with all IRQs disabled.
IO::out8(PIC0_CMD, 0xff);
IO::out8(PIC1_CMD, 0xff);
m_cached_irq_mask = 0xffff;
// ...except IRQ2, since that's needed for the master to let through slave interrupts.
enable_vector(2);
}
UNMAP_AFTER_INIT void PIC::initialize()
{
/* ICW1 (edge triggered mode, cascading controllers, expect ICW4) */
IO::out8(PIC0_CTL, ICW1_INIT | ICW1_ICW4);
IO::out8(PIC1_CTL, ICW1_INIT | ICW1_ICW4);
/* ICW2 (upper 5 bits specify ISR indices, lower 3 idunno) */
IO::out8(PIC0_CMD, IRQ_VECTOR_BASE);
IO::out8(PIC1_CMD, IRQ_VECTOR_BASE + 0x08);
/* ICW3 (configure master/slave relationship) */
IO::out8(PIC0_CMD, 1 << SLAVE_INDEX);
IO::out8(PIC1_CMD, SLAVE_INDEX);
/* ICW4 (set x86 mode) */
IO::out8(PIC0_CMD, ICW4_8086);
IO::out8(PIC1_CMD, ICW4_8086);
// Mask -- start out with all IRQs disabled.
IO::out8(PIC0_CMD, 0xff);
IO::out8(PIC1_CMD, 0xff);
// ...except IRQ2, since that's needed for the master to let through slave interrupts.
enable_vector(2);
dmesgln("PIC: Cascading mode, vectors {:#02x}-{:#02x}", IRQ_VECTOR_BASE, IRQ_VECTOR_BASE + 0xf);
}
u16 PIC::get_isr() const
{
IO::out8(PIC0_CTL, 0x0b);
IO::out8(PIC1_CTL, 0x0b);
u8 isr0 = IO::in8(PIC0_CTL);
u8 isr1 = IO::in8(PIC1_CTL);
return (isr1 << 8) | isr0;
}
u16 PIC::get_irr() const
{
IO::out8(PIC0_CTL, 0x0a);
IO::out8(PIC1_CTL, 0x0a);
u8 irr0 = IO::in8(PIC0_CTL);
u8 irr1 = IO::in8(PIC1_CTL);
return (irr1 << 8) | irr0;
}
}
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