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/ahci/driver.cpp

@@ -14,6 +14,15 @@ ahci_driver::register_device(pci_device *device)
 	log::info(logs::driver, "AHCI registering device %d:%d:%d:",
 			device->bus(), device->device(), device->function());
 
-	m_devices.emplace(device);
+	ahci::hba &hba = m_devices.emplace(device);
 }
 
+ahci::port *
+ahci_driver::find_disk()
+{
+	for (auto &hba : m_devices) {
+		ahci::port *d = hba.find_disk();
+		if (d) return d;
+	}
+	return nullptr;
+}

src/kernel/ahci/driver.h

@@ -22,6 +22,9 @@ public:
 	/// \arg device  The PCI device to remove
 	void unregister_device(pci_device *device);
 
+	/// Debug: find the first disk
+	ahci::port * find_disk();
+
 private:
 	kutil::vector<ahci::hba> m_devices;
 };

src/kernel/ahci/hba.cpp

@@ -1,6 +1,7 @@
 #include <stdint.h>
+#include "ahci/ata.h"
 #include "ahci/hba.h"
-#include "console.h"
+#include "device_manager.h"
 #include "log.h"
 #include "page_manager.h"
 #include "pci.h"
@@ -46,6 +47,13 @@ struct hba_data
 } __attribute__ ((packed));
 
 
+void irq_cb(void *data)
+{
+	hba *h = reinterpret_cast<hba *>(data);
+	h->handle_interrupt();
+}
+
+
 hba::hba(pci_device *device)
 {
 	page_manager *pm = page_manager::get();
@@ -54,6 +62,9 @@ hba::hba(pci_device *device)
 	m_data = reinterpret_cast<hba_data *>(bar5 & ~0xfffull);
 	pm->map_offset_pointer(reinterpret_cast<void **>(&m_data), 0x2000);
 
+	if (! bitfield_has(m_data->cap, hba_cap::ahci_only))
+		m_data->host_control |= 0x80000000; // Enable AHCI mode
+
 	uint32_t icap = static_cast<uint32_t>(m_data->cap);
 
 	unsigned ports = (icap & 0xf) + 1;
@@ -65,24 +76,42 @@ hba::hba(pci_device *device)
 	port_data *pd = reinterpret_cast<port_data *>(
 			kutil::offset_pointer(m_data, 0x100));
 
+	bool needs_interrupt = false;
 	m_ports.ensure_capacity(ports);
 	for (unsigned i = 0; i < ports; ++i) {
 		bool impl = ((m_data->port_impl & (1 << i)) != 0);
 		port &p = m_ports.emplace(i, kutil::offset_pointer(pd, 0x80 * i), impl);
-		if (p.get_state() == port::state::active) {
-			uint8_t buf[512];
-			p.read(1, sizeof(buf), buf);
+		if (p.get_state() == port::state::active)
+			needs_interrupt = true;
+	}
 
-			console *cons = console::get();
-			uint8_t *p = &buf[0];
-			for (int i = 0; i < 8; ++i) {
-				for (int j = 0; j < 16; ++j) {
-					cons->printf(" %02x", *p++);
-				}
-				cons->putc('\n');
+	if (needs_interrupt) {
+		device_manager::get().allocate_msi("AHCI Device", *device, irq_cb, this);
+		m_data->host_control |= 0x02; // enable interrupts
 	}
 }
+
+port *
+hba::find_disk()
+{
+	for (auto &port : m_ports) {
+		if (port.get_state() == port::state::active &&
+			port.get_type() == sata_signature::sata_drive)
+			return &port;
 	}
+
+	return nullptr;
+}
+
+void
+hba::handle_interrupt()
+{
+	for (auto &port : m_ports) {
+		if (m_data->int_status & (1 << port.index())) {
+			port.handle_interrupt();
+		}
+	}
+	m_data->int_status = 0;
 }
 
 } // namespace ahci

src/kernel/ahci/hba.h

@@ -22,6 +22,12 @@ public:
 	/// \arg device  The PCI device for this HBA
 	hba(pci_device *device);
 
+	/// Interrupt handler.
+	void handle_interrupt();
+
+	/// Debug: find the first disk
+	port * find_disk();
+
 private:
 	pci_device *m_device;
 	hba_data *m_data;

src/kernel/ahci/port.cpp

@@ -154,6 +154,7 @@ port::update()
 
 		rebase();
 		m_pending.set_size(32);
+		m_data->interrupt_enable = 1;
 	} else {
 		m_state = state::inactive;
 	}
@@ -290,25 +291,20 @@ port::issue_command(int slot)
 	// Set bit in CI. Note that only new bits should be written, not
 	// previous state.
 	m_data->cmd_issue = (1 << slot);
-
-	// TODO: interrupt-based
-	while (true) {
-		if ((m_data->cmd_issue & (1 << slot)) == 0) break;
-		if (m_data->interrupt_status & 0x40000000) {
-			log::error(logs::driver, "AHCI task file error");
-			// TODO: clean up!
-			return false;
-		}
-		io_wait();
+	return true;
 }
 
-	// This is where interrupt handler would begin
+void
+port::handle_interrupt()
+{
+	log::debug(logs::driver, "AHCI port %d got an interrupt");
+
 	// TODO: handle other states in interrupt_status
 
 	if (m_data->interrupt_status & 0x40000000) {
 		log::error(logs::driver, "AHCI task file error");
 		// TODO: clean up!
-		return false;
+		return;
 	}
 
 	log::debug(logs::driver, "AHCI interrupt status: %08lx  %08lx",
@@ -329,8 +325,7 @@ port::issue_command(int slot)
 		p.type = command_type::none;
 		p.data = nullptr;
 	}
-
-	return true;
+	m_data->interrupt_status = m_data->interrupt_status;
 }
 
 void

src/kernel/ahci/port.h

@@ -27,15 +27,19 @@ public:
 	/// Destructor
 	~port();
 
+	/// Get the index of this port on the HBA
+	/// \returns  The port index
+	inline uint8_t index() const { return m_index; }
+
 	enum class state : uint8_t { unimpl, inactive, active };
 
 	/// Get the current state of this device
 	/// \returns  An enum representing the state
-	state get_state() const { return m_state; }
+	inline state get_state() const { return m_state; }
 
 	/// Get the type signature of this device
 	/// \returns  An enum representing the type of device
-	sata_signature get_type() const { return m_type; }
+	inline sata_signature get_type() const { return m_type; }
 
 	/// Update the state of this object from the register data
 	void update();
@@ -56,6 +60,9 @@ public:
 	/// \returns     True if the command succeeded
 	bool read(uint64_t sector, size_t length, void *dest);
 
+	/// Handle an incoming interrupt
+	void handle_interrupt();
+
 private:
 	/// Rebase the port command structures to a new location in system
 	/// memory, to be allocated from the page manager.

src/kernel/device_manager.cpp

@@ -6,14 +6,17 @@
 #include "acpi_tables.h"
 #include "ahci/driver.h"
 #include "apic.h"
+#include "console.h"
 #include "device_manager.h"
 #include "interrupts.h"
 #include "log.h"
 #include "memory.h"
 #include "page_manager.h"
 
+
 static const char expected_signature[] = "RSD PTR ";
 
+device_manager device_manager::s_instance(nullptr);
 ahci_driver ahcid;
 
 struct acpi1_rsdp
@@ -56,6 +59,21 @@ acpi_table_header::validate(uint32_t expected_type) const
 }
 
 
+void irq2_callback(void *)
+{
+	console *cons = console::get();
+	cons->set_color(11);
+	cons->puts(".");
+	cons->set_color();
+}
+
+void irq4_callback(void *)
+{
+	// TODO: move this to a real serial driver
+	console *cons = console::get();
+	cons->echo();
+}
+
 
 device_manager::device_manager(const void *root_table) :
 	m_lapic(nullptr)
@@ -81,6 +99,11 @@ device_manager::device_manager(const void *root_table) :
 	kassert(sum == 0, "ACPI 2.0 RSDP checksum mismatch.");
 
 	load_xsdt(reinterpret_cast<const acpi_xsdt *>(acpi2->xsdt_address));
+
+	m_irqs.ensure_capacity(32);
+	m_irqs.set_size(16);
+	m_irqs[2] = {"Clock interrupt", irq2_callback, nullptr};
+	m_irqs[4] = {"Serial interrupt", irq4_callback, nullptr};
 }
 
 ioapic *
@@ -281,3 +304,19 @@ device_manager::init_drivers()
 		ahcid.register_device(&device);
 	}
 }
+
+bool
+device_manager::allocate_msi(const char *name, pci_device &device, irq_callback cb, void *data)
+{
+	// TODO: find gaps to fill
+	uint8_t irq = m_irqs.count();
+	isr vector = isr::irq00 + irq;
+	m_irqs.append({name, cb, data});
+
+	log::debug(logs::device, "Allocating IRQ %02x to %s.", irq, name);
+
+	device.write_msi_regs(
+			0xFEE00000,
+			static_cast<uint16_t>(vector));
+	return true;
+}

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;
 };

src/kernel/interrupts.cpp

@@ -4,10 +4,10 @@
 #include "kutil/enum_bitfields.h"
 #include "kutil/memory.h"
 #include "console.h"
+#include "device_manager.h"
 #include "interrupts.h"
 #include "io.h"
 #include "log.h"
-#include "page_manager.h"
 
 enum class gdt_flags : uint8_t
 {
@@ -319,22 +319,9 @@ irq_handler(registers regs)
 {
 	console *cons = console::get();
 	uint8_t irq = get_irq(regs.interrupt);
-
-	switch (irq) {
-	case 2:
+	if (! device_manager::get().dispatch_irq(irq)) {
 		cons->set_color(11);
-		cons->puts(".");
-		cons->set_color();
-		break;
-
-	case 4:
-		// TODO: move this to a real serial driver
-		cons->echo();
-		break;
-
-	default:
-		cons->set_color(11);
-		cons->printf("\nReceived IRQ interrupt: %d (vec %d)\n",
+		cons->printf("\nReceived unknown IRQ: %d (vec %d)\n",
 				irq, regs.interrupt);
 		cons->set_color();
 

src/kernel/main.cpp

@@ -3,6 +3,10 @@
 
 #include "kutil/assert.h"
 #include "kutil/memory.h"
+
+#include "ahci/driver.h"
+#include "ahci/port.h"
+
 #include "console.h"
 #include "cpu.h"
 #include "device_manager.h"
@@ -23,6 +27,8 @@ extern "C" {
 	void *__bss_start, *__bss_end;
 }
 
+extern ahci_driver ahcid;
+
 extern void __kernel_assert(const char *, unsigned, const char *);
 
 void
@@ -79,7 +85,10 @@ kernel_main(popcorn_data *header)
 	// pager->dump_blocks();
 
 	interrupts_init();
-	device_manager devices(header->acpi_table);
+
+	device_manager *devices =
+		new (&device_manager::get()) device_manager(header->acpi_table);
+
 	interrupts_enable();
 
 	cpu_id cpu;
@@ -87,7 +96,25 @@ kernel_main(popcorn_data *header)
 	log::info(logs::boot, "CPU Family %x Model %x Stepping %x",
 			cpu.family(), cpu.model(), cpu.stepping());
 
-	devices.init_drivers();
+	devices->init_drivers();
+
+	ahci::port *disk = ahcid.find_disk();
+	if (disk) {
+		uint8_t buf[512];
+		kutil::memset(buf, 0, 512);
+
+		disk->read(1, sizeof(buf), buf);
+		while (buf[0] == 0) io_wait();
+
+		console *cons = console::get();
+		uint8_t *p = &buf[0];
+		for (int i = 0; i < 8; ++i) {
+			for (int j = 0; j < 16; ++j) {
+				cons->printf(" %02x", *p++);
+			}
+			cons->putc('\n');
+		}
+	}
 
 	// do_error_1();
 	// __asm__ __volatile__("int $15");

src/kernel/pci.cpp

@@ -3,6 +3,28 @@
 #include "interrupts.h"
 #include "pci.h"
 
+struct pci_cap_msi :
+	public pci_cap
+{
+	uint16_t control;
+	uint64_t address;
+	uint16_t data;
+	uint16_t reserved;
+	uint32_t mask;
+	uint32_t pending;
+} __attribute__ ((packed));
+
+struct pci_cap_msix :
+	public pci_cap
+{
+	uint16_t control;
+	uint64_t address;
+	uint16_t data;
+	uint16_t reserved;
+	uint32_t mask;
+	uint32_t pending;
+} __attribute__ ((packed));
+
 
 pci_device::pci_device() :
 	m_base(nullptr),
@@ -20,6 +42,7 @@ pci_device::pci_device() :
 
 pci_device::pci_device(pci_group &group, uint8_t bus, uint8_t device, uint8_t func) :
 	m_base(group.base_for(bus, device, func)),
+	m_msi(nullptr),
 	m_bus_addr(bus_addr(bus, device, func)),
 	m_irq(isr::isrIgnoreF)
 {
@@ -34,8 +57,24 @@ pci_device::pci_device(pci_group &group, uint8_t bus, uint8_t device, uint8_t fu
 	m_header_type = (m_base[3] >> 16) & 0x7f;
 	m_multi = ((m_base[3] >> 16) & 0x80) == 0x80;
 
+	uint16_t *command = reinterpret_cast<uint16_t *>(&m_base[1]);
+	*command |= 0x400; // Mask old INTx style interrupts
+
 	log::info(logs::device, "Found PCIe device at %02d:%02d:%d of type %d.%d id %04x:%04x",
 			bus, device, func, m_class, m_subclass, m_vendor, m_device);
+
+	// Walk the extended capabilities list
+	uint8_t next = m_base[13] & 0xff;
+	while (next) {
+		pci_cap *cap = reinterpret_cast<pci_cap *>(kutil::offset_pointer(m_base, next));
+		next = cap->next;
+
+		if (cap->id == pci_cap::type::msi) {
+			m_msi = cap;
+			pci_cap_msi *mcap = reinterpret_cast<pci_cap_msi *>(cap);
+			mcap->control |= ~0x1; // Mask interrupts
+		}
+	}
 }
 
 uint32_t
@@ -66,6 +105,19 @@ pci_device::set_bar(unsigned i, uint32_t val)
 	m_base[4+i] = val;
 }
 
+void
+pci_device::write_msi_regs(addr_t address, uint16_t data)
+{
+	kassert(m_msi, "Tried to write MSI for a device without that cap");
+	if (m_msi->id == pci_cap::type::msi) {
+		pci_cap_msi *mcap = reinterpret_cast<pci_cap_msi *>(m_msi);
+		mcap->address = address;
+		mcap->data = data;
+		mcap->control |= 1;
+	} else {
+		kassert(0, "MIS-X is NYI");
+	}
+}
 
 bool
 pci_group::has_device(uint8_t bus, uint8_t device, uint8_t func)

src/kernel/pci.h

@@ -7,6 +7,18 @@
 struct pci_group;
 enum class isr : uint8_t;
 
+struct pci_cap
+{
+	enum class type : uint8_t
+	{
+		msi		= 0x05,
+		msix	= 0x11
+	};
+
+	type id;
+	uint8_t next;
+} __attribute__ ((packed));
+
 
 /// Information about a discovered PCIe device
 class pci_device
@@ -60,6 +72,11 @@ public:
 	/// \arg val The value to write
 	void set_bar(unsigned i, uint32_t val);
 
+	/// Write to the MSI registers
+	/// \arg addr  The address to write to the MSI address registers
+	/// \arg data  The value to write to the MSI data register
+	void write_msi_regs(addr_t addr, uint16_t data);
+
 	/// Get a bus address, given the bus/device/function numbers.
 	/// \arg bus    Number of the bus
 	/// \arg device Index of the device on the bus
@@ -72,6 +89,7 @@ public:
 
 private:
 	uint32_t *m_base;
+	pci_cap *m_msi;
 
 	/// Bus address: 15:8 bus, 7:3 device, 2:0 device
 	uint16_t m_bus_addr;