Enable AHCI interrupts.

* Implement MSI style interrupts
* Move interrupt handling to device_manager for IRQs
* Give device_manager the ability to allocate IRQs
* Move achi::port to an interrupt-based scheme

src/kernel/device_manager.h

@@ -10,6 +10,8 @@ struct acpi_mcfg;
 class lapic;
 class ioapic;
 
+using irq_callback = void (*)(void *);
+
 
 /// Manager for all system hardware devices
 class device_manager
@@ -19,6 +21,10 @@ public:
 	/// \arg root_table   Pointer to the ACPI RSDP
 	device_manager(const void *root_table);
 
+	/// Get the system global device manager.
+	/// \returns  A reference to the system device manager
+	static device_manager & get() { return s_instance; }
+
 	/// Get the LAPIC
 	/// \returns An object representing the local APIC
 	lapic * get_lapic() { return m_lapic; }
@@ -32,6 +38,33 @@ public:
 	/// Intialize drivers for the current device list.
 	void init_drivers();
 
+	/// Allocate an MSI IRQ for a device
+	/// \arg name    Name of the interrupt, for display to user
+	/// \arg device  Device this MSI is being allocated for
+	/// \arg cb      Callback to call when the interrupt is received
+	/// \arg data    Data to pass to the callback
+	/// \returns     True if an interrupt was allocated successfully
+	bool allocate_msi(
+			const char *name,
+			pci_device &device,
+			irq_callback cb,
+			void *data);
+
+	/// Dispatch an IRQ interrupt
+	/// \arg irq  The irq number of the interrupt
+	/// \returns  True if the interrupt was handled
+	inline bool dispatch_irq(uint8_t irq)
+	{
+		if (irq < m_irqs.count()) {
+			irq_allocation &cba = m_irqs[irq];
+			if (cba.callback) {
+				cba.callback(cba.data);
+				return true;
+			}
+		}
+		return false;
+	}
+
 private:
 	/// Parse the ACPI XSDT and load relevant sub-tables.
 	/// \arg xsdt  Pointer to the XSDT from the firmware
@@ -49,12 +82,27 @@ private:
 	/// device list. The device list is destroyed and rebuilt.
 	void probe_pci();
 
+	/// Handle a bad IRQ. Called when an interrupt is dispatched
+	/// that has no callback.
+	void bad_irq(uint8_t irq);
+
 	lapic *m_lapic;
 	kutil::vector<ioapic *> m_ioapics;
 
 	kutil::vector<pci_group> m_pci;
 	kutil::vector<pci_device> m_devices;
 
+	struct irq_allocation
+	{
+		const char *name;
+		irq_callback callback;
+		void *data;
+	};
+	kutil::vector<irq_allocation> m_irqs;
+
+	static device_manager s_instance;
+
 	device_manager() = delete;
 	device_manager(const device_manager &) = delete;
+	device_manager operator=(const device_manager &) = delete;
 };