Kernel: Introduce IRQ sharing support

The support is very basic - Each component that needs to handle IRQs
inherits from InterruptHandler class. When the InterruptHandler
constructor is called it registers itself in a SharedInterruptHandler.
When an IRQ is fired, the SharedInterruptHandler is invoked, then it
iterates through a list of the registered InterruptHandlers.

Also, InterruptEnabler class was created to provide a way to enable IRQ
handling temporarily, similar to InterruptDisabler (in CPU.h, which does
the opposite).

In addition to that a PCI::Device class has been added, that inherits
from InterruptHandler.

Kernel/InterruptHandler.cpp

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2020, Liav A. <[email protected]>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <Kernel/InterruptHandler.h>
+#include <Kernel/SharedInterruptHandler.h>
+
+InterruptHandler::InterruptHandler(u8 irq)
+ : m_irq_number(irq)
+{
+ SharedInterruptHandler::from(m_irq_number).register_handler(*this);
+ disable_interrupts();
+}
+
+InterruptHandler::~InterruptHandler()
+{
+ disable_interrupts();
+ SharedInterruptHandler::from(m_irq_number).unregister_handler(*this);
+}
+
+void InterruptHandler::enable_interrupts()
+{
+ m_enabled = true;
+}
+
+void InterruptHandler::change_irq_number(u8 irq_number)
+{
+ bool was_enabled = m_enabled;
+ disable_interrupts();
+ SharedInterruptHandler::from(m_irq_number).unregister_handler(*this);
+ m_irq_number = irq_number;
+ SharedInterruptHandler::from(m_irq_number).register_handler(*this);
+ if (was_enabled)
+ enable_interrupts();
+}
+
+void InterruptHandler::disable_interrupts()
+{
+ m_enabled = false;
+}
+
+InterruptHandler::Enabler::Enabler(InterruptHandler& handler)
+ : m_handler(handler)
+ , m_was_enabled(m_handler.is_enabled())
+{
+ m_handler.enable_interrupts();
+}
+InterruptHandler::Enabler::~Enabler()
+{
+ if (!m_was_enabled)
+ m_handler.disable_interrupts();
+}

Kernel/InterruptHandler.h

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2020, Liav A. <[email protected]>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+
+class InterruptHandler {
+public:
+ class Enabler {
+ public:
+ explicit Enabler(InterruptHandler&);
+ ~Enabler();
+
+ private:
+ InterruptHandler& m_handler;
+ bool m_was_enabled;
+ };
+ friend class Enabler;
+
+public:
+ virtual ~InterruptHandler();
+ virtual void handle_interrupt() = 0;
+
+ u8 irq_number() const { return m_irq_number; }
+ bool is_enabled() const { return m_enabled; }
+
+protected:
+ void enable_interrupts();
+ void change_irq_number(u8 irq_number);
+ void disable_interrupts();
+ explicit InterruptHandler(u8 irq);
+
+private:
+ bool m_enabled { false };
+ u8 m_irq_number { 0 };
+};

Kernel/PCI/Definitions.h

@@ -178,5 +178,6 @@ class Access;
 class MMIOAccess;
 class IOAccess;
 class MMIOSegment;
+class Device;
 
 }

Kernel/PCI/Device.cpp

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2020, Liav A. <[email protected]>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <Kernel/PCI/Device.h>
+
+PCI::Device::Device(PCI::Address address)
+ : InterruptHandler(PCI::get_interrupt_line(address))
+ , m_pci_address(address)
+{
+ // FIXME: Register PCI device somewhere...
+}
+
+PCI::Device::Device(PCI::Address address, u8 interrupt_vector)
+ : InterruptHandler(interrupt_vector)
+ , m_pci_address(address)
+{
+ // FIXME: Register PCI device somewhere...
+}
+
+PCI::Device::~Device()
+{
+ // FIXME: Unregister the device
+}

Kernel/PCI/Device.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2020, Liav A. <[email protected]>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Types.h>
+#include <Kernel/InterruptHandler.h>
+#include <Kernel/PCI/Definitions.h>
+
+class PCI::Device : public InterruptHandler {
+public:
+ Address get_pci_address() const { return m_pci_address; };
+
+protected:
+ Device(Address pci_address);
+ Device(Address pci_address, u8 interrupt_vector);
+ ~Device();
+
+private:
+ Address m_pci_address;
+};

Kernel/SharedInterruptHandler.cpp

@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2020, Liav A. <[email protected]>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <Kernel/Arch/i386/CPU.h>
+#include <Kernel/Arch/i386/PIC.h>
+#include <Kernel/InterruptHandler.h>
+#include <Kernel/SharedInterruptHandler.h>
+
+//#define INTERRUPT_DEBUG
+
+SharedInterruptHandler& SharedInterruptHandler::from(u8 interrupt_number)
+{
+ return get_interrupt_handler(interrupt_number);
+}
+
+void SharedInterruptHandler::initialize(u8 interrupt_number)
+{
+ new SharedInterruptHandler(interrupt_number);
+}
+
+void SharedInterruptHandler::register_handler(InterruptHandler& handler)
+{
+#ifdef INTERRUPT_DEBUG
+ kprintf("Interrupt Handler registered @ Shared Interrupt Handler %d\n", m_interrupt_number);
+#endif
+ m_handlers.set(&handler);
+ enable_interrupt_vector();
+}
+void SharedInterruptHandler::unregister_handler(InterruptHandler& handler)
+{
+#ifdef INTERRUPT_DEBUG
+ kprintf("Interrupt Handler unregistered @ Shared Interrupt Handler %d\n", m_interrupt_number);
+#endif
+ m_handlers.remove(&handler);
+ if (m_handlers.is_empty())
+ disable_interrupt_vector();
+}
+
+SharedInterruptHandler::SharedInterruptHandler(u8 interrupt_number)
+ : m_interrupt_number(interrupt_number)
+ , m_enabled(true)
+{
+#ifdef INTERRUPT_DEBUG
+ kprintf("Shared Interrupt Handler registered @ %d\n", m_interrupt_number);
+#endif
+ register_shared_interrupt_handler(m_interrupt_number, *this);
+ disable_interrupt_vector();
+}
+
+SharedInterruptHandler::~SharedInterruptHandler()
+{
+#ifdef INTERRUPT_DEBUG
+ kprintf("Shared Interrupt Handler unregistered @ %d\n", m_interrupt_number);
+#endif
+ disable_interrupt_vector();
+ unregister_shared_interrupt_handler(m_interrupt_number, *this);
+}
+
+void SharedInterruptHandler::handle_interrupt()
+{
+#ifdef INTERRUPT_DEBUG
+ kprintf("Interrupt @ %d\n", m_interrupt_number);
+ kprintf("Interrupt Handlers registered - %d\n", m_handlers.size());
+#endif
+ int i = 0;
+ for (auto* handler : m_handlers) {
+#ifdef INTERRUPT_DEBUG
+ kprintf("Going for Interrupt Handling @ %d, Shared Interrupt %d\n", i, m_interrupt_number);
+#endif
+ ASSERT(handler != nullptr);
+ if (handler->is_enabled())
+ handler->handle_interrupt();
+
+#ifdef INTERRUPT_DEBUG
+ kprintf("Going for Interrupt Handling @ %d, Shared Interrupt %d - End\n", i, m_interrupt_number);
+#endif
+ i++;
+ }
+ // FIXME: Determine if we use IRQs or MSIs (in the future) to send EOI...
+}
+
+void SharedInterruptHandler::enable_interrupt_vector()
+{
+ if (m_enabled)
+ return;
+ m_enabled = true;
+ // FIXME: Determine if we use IRQs or MSIs (in the future) to enable the interrupt vector...
+ PIC::enable(m_interrupt_number);
+}
+
+void SharedInterruptHandler::disable_interrupt_vector()
+{
+ if (!m_enabled)
+ return;
+ m_enabled = false;
+ // FIXME: Determine if we use IRQs or MSIs (in the future) to disable the interrupt vector...
+ PIC::disable(m_interrupt_number);
+}