haiku.git

/*
 * Copyright 2011-2021, Haiku, Inc. All rights reserved.
 * Distributed under the terms of the MIT License.
 *
 * Authors:
 *		Augustin Cavalier <waddlesplash>
 *		Jian Chiang <j.jian.chiang@gmail.com>
 *		Jérôme Duval <jerome.duval@gmail.com>
 *		Akshay Jaggi <akshay1994.leo@gmail.com>
 *		Michael Lotz <mmlr@mlotz.ch>
 *		Alexander von Gluck <kallisti5@unixzen.com>
 */


#include <stdio.h>

#include <bus/PCI.h>
#include <USB3.h>
#include <KernelExport.h>

#include <ByteOrder.h>
#include <util/AutoLock.h>

#include "xhci.h"


#define CALLED(x...)	TRACE_MODULE("CALLED %s\n", __PRETTY_FUNCTION__)


#define USB_MODULE_NAME	"xhci"

device_manager_info* gDeviceManager;
static usb_for_controller_interface* gUSB;


#define XHCI_PCI_DEVICE_MODULE_NAME "busses/usb/xhci/pci/driver_v1"
#define XHCI_PCI_USB_BUS_MODULE_NAME "busses/usb/xhci/device_v1"


typedef struct {
	XHCI* xhci;
	pci_device_module_info* pci;
	pci_device* device;

	pci_info pciinfo;

	device_node* node;
	device_node* driver_node;
} xhci_pci_sim_info;


//	#pragma mark -


static status_t
init_bus(device_node* node, void** bus_cookie)
{
	CALLED();

	driver_module_info* driver;
	xhci_pci_sim_info* bus;
	device_node* parent = gDeviceManager->get_parent_node(node);
	gDeviceManager->get_driver(parent, &driver, (void**)&bus);
	gDeviceManager->put_node(parent);

	Stack *stack;
	if (gUSB->get_stack((void**)&stack) != B_OK)
		return B_ERROR;

	XHCI *xhci = new(std::nothrow) XHCI(&bus->pciinfo, bus->pci, bus->device, stack, node);
	if (xhci == NULL) {
		return B_NO_MEMORY;
	}

	if (xhci->InitCheck() < B_OK) {
		TRACE_MODULE_ERROR("bus failed init check\n");
		delete xhci;
		return B_ERROR;
	}

	if (xhci->Start() != B_OK) {
		delete xhci;
		return B_ERROR;
	}

	*bus_cookie = xhci;

	return B_OK;
}


static void
uninit_bus(void* bus_cookie)
{
	CALLED();
	XHCI* xhci = (XHCI*)bus_cookie;
	delete xhci;
}


static status_t
register_child_devices(void* cookie)
{
	CALLED();
	xhci_pci_sim_info* bus = (xhci_pci_sim_info*)cookie;
	device_node* node = bus->driver_node;

	char prettyName[25];
	sprintf(prettyName, "XHCI Controller %" B_PRIu16, 0);

	device_attr attrs[] = {
		// properties of this controller for the usb bus manager
		{ B_DEVICE_PRETTY_NAME, B_STRING_TYPE,
			{ .string = prettyName }},
		{ B_DEVICE_FIXED_CHILD, B_STRING_TYPE,
			{ .string = USB_FOR_CONTROLLER_MODULE_NAME }},

		// private data to identify the device
		{ NULL }
	};

	return gDeviceManager->register_node(node, XHCI_PCI_USB_BUS_MODULE_NAME,
		attrs, NULL, NULL);
}


static status_t
init_device(device_node* node, void** device_cookie)
{
	CALLED();
	xhci_pci_sim_info* bus = (xhci_pci_sim_info*)calloc(1,
		sizeof(xhci_pci_sim_info));
	if (bus == NULL)
		return B_NO_MEMORY;

	pci_device_module_info* pci;
	pci_device* device;
	{
		device_node* pciParent = gDeviceManager->get_parent_node(node);
		gDeviceManager->get_driver(pciParent, (driver_module_info**)&pci,
			(void**)&device);
		gDeviceManager->put_node(pciParent);
	}

	bus->pci = pci;
	bus->device = device;
	bus->driver_node = node;

	pci_info *pciInfo = &bus->pciinfo;
	pci->get_pci_info(device, pciInfo);

	*device_cookie = bus;
	return B_OK;
}


static void
uninit_device(void* device_cookie)
{
	CALLED();
	xhci_pci_sim_info* bus = (xhci_pci_sim_info*)device_cookie;
	free(bus);
}


static status_t
register_device(device_node* parent)
{
	CALLED();
	device_attr attrs[] = {
		{B_DEVICE_PRETTY_NAME, B_STRING_TYPE, {.string = "XHCI PCI"}},
		{}
	};

	return gDeviceManager->register_node(parent,
		XHCI_PCI_DEVICE_MODULE_NAME, attrs, NULL, NULL);
}


static float
supports_device(device_node* parent)
{
	CALLED();
	const char* bus;
	uint16 type, subType, api;

	// make sure parent is a XHCI PCI device node
	if (gDeviceManager->get_attr_string(parent, B_DEVICE_BUS, &bus, false)
		< B_OK) {
		return -1;
	}

	if (strcmp(bus, "pci") != 0)
		return 0.0f;

	if (gDeviceManager->get_attr_uint16(parent, B_DEVICE_SUB_TYPE, &subType,
			false) < B_OK
		|| gDeviceManager->get_attr_uint16(parent, B_DEVICE_TYPE, &type,
			false) < B_OK
		|| gDeviceManager->get_attr_uint16(parent, B_DEVICE_INTERFACE, &api,
			false) < B_OK) {
		TRACE_MODULE("Could not find type/subtype/interface attributes\n");
		return -1;
	}

	if (type == PCI_serial_bus && subType == PCI_usb && api == PCI_usb_xhci) {
		pci_device_module_info* pci;
		pci_device* device;
		gDeviceManager->get_driver(parent, (driver_module_info**)&pci,
			(void**)&device);
		TRACE_MODULE("XHCI Device found!\n");

		return 0.8f;
	}

	return 0.0f;
}


static const char*
xhci_error_string(uint32 error)
{
	switch (error) {
		case COMP_INVALID: return "Invalid";
		case COMP_SUCCESS: return "Success";
		case COMP_DATA_BUFFER: return "Data buffer";
		case COMP_BABBLE: return "Babble detected";
		case COMP_USB_TRANSACTION: return "USB transaction";
		case COMP_TRB: return "TRB";
		case COMP_STALL: return "Stall";
		case COMP_RESOURCE: return "Resource";
		case COMP_BANDWIDTH: return "Bandwidth";
		case COMP_NO_SLOTS: return "No slots";
		case COMP_INVALID_STREAM: return "Invalid stream";
		case COMP_SLOT_NOT_ENABLED: return "Slot not enabled";
		case COMP_ENDPOINT_NOT_ENABLED: return "Endpoint not enabled";
		case COMP_SHORT_PACKET: return "Short packet";
		case COMP_RING_UNDERRUN: return "Ring underrun";
		case COMP_RING_OVERRUN: return "Ring overrun";
		case COMP_VF_RING_FULL: return "VF Event Ring Full";
		case COMP_PARAMETER: return "Parameter";
		case COMP_BANDWIDTH_OVERRUN: return "Bandwidth overrun";
		case COMP_CONTEXT_STATE: return "Context state";
		case COMP_NO_PING_RESPONSE: return "No ping response";
		case COMP_EVENT_RING_FULL: return "Event ring full";
		case COMP_INCOMPATIBLE_DEVICE: return "Incompatible device";
		case COMP_MISSED_SERVICE: return "Missed service";
		case COMP_COMMAND_RING_STOPPED: return "Command ring stopped";
		case COMP_COMMAND_ABORTED: return "Command aborted";
		case COMP_STOPPED: return "Stopped";
		case COMP_STOPPED_LENGTH_INVALID: return "Stopped (length invalid)";
		case COMP_MAX_EXIT_LATENCY: return "Max exit latency too large";
		case COMP_ISOC_OVERRUN: return "Isoch buffer overrun";
		case COMP_EVENT_LOST: return "Event lost";
		case COMP_UNDEFINED: return "Undefined";
		case COMP_INVALID_STREAM_ID: return "Invalid stream ID";
		case COMP_SECONDARY_BANDWIDTH: return "Secondary bandwidth";
		case COMP_SPLIT_TRANSACTION: return "Split transaction";

		default: return "Undefined";
	}
}


static status_t
xhci_error_status(uint32 error, bool directionIn)
{
	switch (error) {
		case COMP_SHORT_PACKET:
		case COMP_SUCCESS:
			return B_OK;
		case COMP_DATA_BUFFER:
			return directionIn ? B_DEV_WRITE_ERROR : B_DEV_READ_ERROR;
		case COMP_BABBLE:
			return directionIn ? B_DEV_DATA_OVERRUN : B_DEV_DATA_UNDERRUN;
		case COMP_RING_UNDERRUN:
			return B_DEV_FIFO_UNDERRUN;
		case COMP_RING_OVERRUN:
			return B_DEV_FIFO_OVERRUN;
		case COMP_MISSED_SERVICE:
			return B_DEV_TOO_LATE;
		case COMP_USB_TRANSACTION:
			return B_DEV_CRC_ERROR;
		case COMP_STALL:
			return B_DEV_STALLED;
		default:
			return B_DEV_STALLED;
	}
}


module_dependency module_dependencies[] = {
	{ USB_FOR_CONTROLLER_MODULE_NAME, (module_info**)&gUSB },
	{ B_DEVICE_MANAGER_MODULE_NAME, (module_info**)&gDeviceManager },
	{}
};


static usb_bus_interface gXHCIPCIDeviceModule = {
	{
		{
			XHCI_PCI_USB_BUS_MODULE_NAME,
			0,
			NULL
		},
		NULL,  // supports device
		NULL,  // register device
		init_bus,
		uninit_bus,
		NULL,  // register child devices
		NULL,  // rescan
		NULL,  // device removed
	},
};

// Root device that binds to the PCI bus. It will register an usb_bus_interface
// node for each device.
static driver_module_info sXHCIDevice = {
	{
		XHCI_PCI_DEVICE_MODULE_NAME,
		0,
		NULL
	},
	supports_device,
	register_device,
	init_device,
	uninit_device,
	register_child_devices,
	NULL, // rescan
	NULL, // device removed
};

module_info* modules[] = {
	(module_info* )&sXHCIDevice,
	(module_info* )&gXHCIPCIDeviceModule,
	NULL
};


XHCI::XHCI(pci_info *info, 	pci_device_module_info* pci, pci_device* device, Stack *stack,
	device_node* node)
	:	BusManager(stack, node),
		fRegisterArea(-1),
		fRegisters(NULL),
		fPCIInfo(info),
		fPci(pci),
		fDevice(device),
		fStack(stack),
		fIRQ(0),
		fUseMSI(false),
		fErstArea(-1),
		fDcbaArea(-1),
		fCmdCompSem(-1),
		fStopThreads(false),
		fRootHub(NULL),
		fPortCount(0),
		fSlotCount(0),
		fScratchpadCount(0),
		fContextSizeShift(0),
		fFinishedHead(NULL),
		fFinishTransfersSem(-1),
		fFinishThread(-1),
		fEventSem(-1),
		fEventThread(-1),
		fEventIdx(0),
		fCmdIdx(0),
		fEventCcs(1),
		fCmdCcs(1)
{
	B_INITIALIZE_SPINLOCK(&fSpinlock);
	mutex_init(&fFinishedLock, "XHCI finished transfers");
	mutex_init(&fEventLock, "XHCI event handler");

	if (BusManager::InitCheck() < B_OK) {
		TRACE_ERROR("bus manager failed to init\n");
		return;
	}

	TRACE("constructing new XHCI host controller driver\n");
	fInitOK = false;

	// enable busmaster and memory mapped access
	uint16 command = fPci->read_pci_config(fDevice, PCI_command, 2);
	command &= ~(PCI_command_io | PCI_command_int_disable);
	command |= PCI_command_master | PCI_command_memory;

	fPci->write_pci_config(fDevice, PCI_command, 2, command);

	// map the registers (low + high for 64-bit when requested)
	phys_addr_t physicalAddress = fPCIInfo->u.h0.base_registers[0];
	if ((fPCIInfo->u.h0.base_register_flags[0] & PCI_address_type)
			== PCI_address_type_64) {
		physicalAddress |= (uint64)fPCIInfo->u.h0.base_registers[1] << 32;
	}

	size_t mapSize = fPCIInfo->u.h0.base_register_sizes[0];

	TRACE("map registers %08" B_PRIxPHYSADDR ", size: %" B_PRIuSIZE "\n",
		physicalAddress, mapSize);

	fRegisterArea = map_physical_memory("XHCI memory mapped registers",
		physicalAddress, mapSize, B_ANY_KERNEL_BLOCK_ADDRESS,
		B_KERNEL_READ_AREA | B_KERNEL_WRITE_AREA,
		(void **)&fRegisters);
	if (fRegisterArea < B_OK) {
		TRACE_ERROR("failed to map register memory\n");
		return;
	}

	// determine the register offsets
	fCapabilityRegisterOffset = 0;
	fOperationalRegisterOffset = HCI_CAPLENGTH(ReadCapReg32(XHCI_HCI_CAPLENGTH));
	fRuntimeRegisterOffset = ReadCapReg32(XHCI_RTSOFF) & ~0x1F;
	fDoorbellRegisterOffset = ReadCapReg32(XHCI_DBOFF) & ~0x3;

	TRACE("mapped registers: %p\n", fRegisters);
	TRACE("operational register offset: %" B_PRId32 "\n", fOperationalRegisterOffset);
	TRACE("runtime register offset: %" B_PRId32 "\n", fRuntimeRegisterOffset);
	TRACE("doorbell register offset: %" B_PRId32 "\n", fDoorbellRegisterOffset);

	int32 interfaceVersion = HCI_VERSION(ReadCapReg32(XHCI_HCI_VERSION));
	if (interfaceVersion < 0x0090 || interfaceVersion > 0x0120) {
		TRACE_ERROR("unsupported interface version: 0x%04" B_PRIx32 "\n",
			interfaceVersion);
		return;
	}
	TRACE_ALWAYS("interface version: 0x%04" B_PRIx32 "\n", interfaceVersion);

	TRACE_ALWAYS("structural parameters: 1:0x%08" B_PRIx32 " 2:0x%08"
		B_PRIx32 " 3:0x%08" B_PRIx32 "\n", ReadCapReg32(XHCI_HCSPARAMS1),
		ReadCapReg32(XHCI_HCSPARAMS2), ReadCapReg32(XHCI_HCSPARAMS3));

	uint32 cparams = ReadCapReg32(XHCI_HCCPARAMS);
	if (cparams == 0xffffffff)
		return;
	TRACE_ALWAYS("capability parameters: 0x%08" B_PRIx32 "\n", cparams);

	// if 64 bytes context structures, then 1
	fContextSizeShift = HCC_CSZ(cparams);

	// Assume ownership of the controller from the BIOS.
	uint32 eec = 0xffffffff;
	uint32 eecp = HCS0_XECP(cparams) << 2;
	for (; eecp != 0 && XECP_NEXT(eec) != 0; eecp += XECP_NEXT(eec) << 2) {
		TRACE("eecp register: 0x%08" B_PRIx32 "\n", eecp);

		eec = ReadCapReg32(eecp);
		if (eec == 0xffffffff)
			break;
		if (XECP_ID(eec) != XHCI_LEGSUP_CAPID)
			continue;

		if (eec & XHCI_LEGSUP_BIOSOWNED) {
			TRACE_ALWAYS("the host controller is bios owned, claiming"
				" ownership\n");
			WriteCapReg32(eecp, eec | XHCI_LEGSUP_OSOWNED);

			for (int32 i = 0; i < 20; i++) {
				eec = ReadCapReg32(eecp);

				if ((eec & XHCI_LEGSUP_BIOSOWNED) == 0)
					break;

				TRACE_ALWAYS("controller is still bios owned, waiting\n");
				snooze(50000);
			}

			if (eec & XHCI_LEGSUP_BIOSOWNED) {
				TRACE_ERROR("bios won't give up control over the host "
					"controller (ignoring)\n");
			} else if (eec & XHCI_LEGSUP_OSOWNED) {
				TRACE_ALWAYS("successfully took ownership of the host "
					"controller\n");
			}

			// Force off the BIOS owned flag, and clear all SMIs. Some BIOSes
			// do indicate a successful handover but do not remove their SMIs
			// and then freeze the system when interrupts are generated.
			WriteCapReg32(eecp, eec & ~XHCI_LEGSUP_BIOSOWNED);
		}

		uint32 legctlsts = ReadCapReg32(eecp + XHCI_LEGCTLSTS);
		legctlsts &= (XHCI_LEGCTLSTS_RESERVED_BITS | XHCI_LEGCTLSTS_READONLY_BITS);
		WriteCapReg32(eecp + XHCI_LEGCTLSTS, legctlsts);
		break;
	}

	// We need to explicitly take ownership of EHCI ports on earlier Intel chipsets.
	if (fPCIInfo->vendor_id == PCI_VENDOR_INTEL) {
		switch (fPCIInfo->device_id) {
			case PCI_DEVICE_INTEL_PANTHER_POINT_XHCI:
			case PCI_DEVICE_INTEL_LYNX_POINT_XHCI:
			case PCI_DEVICE_INTEL_LYNX_POINT_LP_XHCI:
			case PCI_DEVICE_INTEL_BAYTRAIL_XHCI:
			case PCI_DEVICE_INTEL_WILDCAT_POINT_XHCI:
			case PCI_DEVICE_INTEL_WILDCAT_POINT_LP_XHCI:
				_SwitchIntelPorts();
				break;
		}
	}

	// halt the host controller
	if (ControllerHalt() < B_OK) {
		return;
	}

	// reset the host controller
	if (ControllerReset() < B_OK) {
		TRACE_ERROR("host controller failed to reset\n");
		return;
	}

	fCmdCompSem = create_sem(0, "XHCI Command Complete");
	fFinishTransfersSem = create_sem(0, "XHCI Finish Transfers");
	fEventSem = create_sem(0, "XHCI Event");
	if (fFinishTransfersSem < B_OK || fCmdCompSem < B_OK || fEventSem < B_OK) {
		TRACE_ERROR("failed to create semaphores\n");
		return;
	}

	// create event handler thread
	fEventThread = spawn_kernel_thread(EventThread, "xhci event thread",
		B_URGENT_PRIORITY, (void *)this);
	resume_thread(fEventThread);

	// create finisher service thread
	fFinishThread = spawn_kernel_thread(FinishThread, "xhci finish thread",
		B_URGENT_PRIORITY - 1, (void *)this);
	resume_thread(fFinishThread);

	// Find the right interrupt vector, using MSIs if available.
	fIRQ = fPCIInfo->u.h0.interrupt_line;
	if (fIRQ == 0xFF)
		fIRQ = 0;

#if 0
	if (fPci->get_msix_count(fDevice) >= 1) {
		uint8 msiVector = 0;
		if (fPci->configure_msix(fDevice, 1, &msiVector) == B_OK
			&& fPci->enable_msix(fDevice) == B_OK) {
			TRACE_ALWAYS("using MSI-X\n");
			fIRQ = msiVector;
			fUseMSI = true;
		}
	} else
#endif
	if (fPci->get_msi_count(fDevice) >= 1) {
		uint32 msiVector = 0;
		if (fPci->configure_msi(fDevice, 1, &msiVector) == B_OK
			&& fPci->enable_msi(fDevice) == B_OK) {
			TRACE_ALWAYS("using message signaled interrupts\n");
			fIRQ = msiVector;
			fUseMSI = true;
		}
	}

	if (fIRQ == 0) {
		TRACE_MODULE_ERROR("device PCI:%d:%d:%d was assigned an invalid IRQ\n",
			fPCIInfo->bus, fPCIInfo->device, fPCIInfo->function);
		return;
	}

	// Install the interrupt handler
	TRACE("installing interrupt handler\n");
	install_io_interrupt_handler(fIRQ, InterruptHandler, (void *)this, 0);

	memset(fPortSpeeds, 0, sizeof(fPortSpeeds));
	memset(fDevices, 0, sizeof(fDevices));

	fInitOK = true;
	TRACE("driver construction successful\n");
}


XHCI::~XHCI()
{
	TRACE("tear down XHCI host controller driver\n");

	WriteOpReg(XHCI_CMD, 0);

	int32 result = 0;
	fStopThreads = true;
	delete_sem(fCmdCompSem);
	delete_sem(fFinishTransfersSem);
	delete_sem(fEventSem);
	wait_for_thread(fFinishThread, &result);
	wait_for_thread(fEventThread, &result);

	mutex_destroy(&fFinishedLock);
	mutex_destroy(&fEventLock);

	remove_io_interrupt_handler(fIRQ, InterruptHandler, (void *)this);

	delete_area(fRegisterArea);
	delete_area(fErstArea);
	for (uint32 i = 0; i < fScratchpadCount; i++)
		delete_area(fScratchpadArea[i]);
	delete_area(fDcbaArea);

	if (fUseMSI) {
		fPci->disable_msi(fDevice);
		fPci->unconfigure_msi(fDevice);
	}
}


void
XHCI::_SwitchIntelPorts()
{
	TRACE("Looking for EHCI owned ports\n");
	uint32 ports = fPci->read_pci_config(fDevice, XHCI_INTEL_USB3PRM, 4);
	TRACE("Superspeed Ports: 0x%" B_PRIx32 "\n", ports);
	fPci->write_pci_config(fDevice, XHCI_INTEL_USB3_PSSEN, 4, ports);
	ports = fPci->read_pci_config(fDevice, XHCI_INTEL_USB3_PSSEN, 4);
	TRACE("Superspeed ports now under XHCI : 0x%" B_PRIx32 "\n", ports);
	ports = fPci->read_pci_config(fDevice, XHCI_INTEL_USB2PRM, 4);
	TRACE("USB 2.0 Ports : 0x%" B_PRIx32 "\n", ports);
	fPci->write_pci_config(fDevice, XHCI_INTEL_XUSB2PR, 4, ports);
	ports = fPci->read_pci_config(fDevice, XHCI_INTEL_XUSB2PR, 4);
	TRACE("USB 2.0 ports now under XHCI: 0x%" B_PRIx32 "\n", ports);
}


status_t
XHCI::Start()
{
	TRACE_ALWAYS("starting XHCI host controller\n");
	TRACE("usbcmd: 0x%08" B_PRIx32 "; usbsts: 0x%08" B_PRIx32 "\n",
		ReadOpReg(XHCI_CMD), ReadOpReg(XHCI_STS));

	if (WaitOpBits(XHCI_STS, STS_CNR, 0) != B_OK) {
		TRACE("Start() failed STS_CNR\n");
	}

	if ((ReadOpReg(XHCI_CMD) & CMD_RUN) != 0) {
		TRACE_ERROR("Start() warning, starting running XHCI controller!\n");
	}

	if ((ReadOpReg(XHCI_PAGESIZE) & (1 << 0)) == 0) {
		TRACE_ERROR("controller does not support 4K page size\n");
		return B_ERROR;
	}

	// read port count from capability register
	uint32 capabilities = ReadCapReg32(XHCI_HCSPARAMS1);
	fPortCount = HCS_MAX_PORTS(capabilities);
	if (fPortCount == 0) {
		TRACE_ERROR("invalid number of ports: %u\n", fPortCount);
		return B_ERROR;
	}

	fSlotCount = HCS_MAX_SLOTS(capabilities);
	if (fSlotCount > XHCI_MAX_DEVICES)
		fSlotCount = XHCI_MAX_DEVICES;
	WriteOpReg(XHCI_CONFIG, fSlotCount);

	// find out which protocol is used for each port
	uint8 portFound = 0;
	uint32 cparams = ReadCapReg32(XHCI_HCCPARAMS);
	uint32 eec = 0xffffffff;
	uint32 eecp = HCS0_XECP(cparams) << 2;
	for (; eecp != 0 && XECP_NEXT(eec) && portFound < fPortCount;
		eecp += XECP_NEXT(eec) << 2) {
		eec = ReadCapReg32(eecp);
		if (XECP_ID(eec) != XHCI_SUPPORTED_PROTOCOLS_CAPID)
			continue;
		if (XHCI_SUPPORTED_PROTOCOLS_0_MAJOR(eec) > 3)
			continue;
		uint32 temp = ReadCapReg32(eecp + 8);
		uint32 offset = XHCI_SUPPORTED_PROTOCOLS_1_OFFSET(temp);
		uint32 count = XHCI_SUPPORTED_PROTOCOLS_1_COUNT(temp);
		if (offset == 0 || count == 0)
			continue;
		offset--;
		for (uint32 i = offset; i < offset + count; i++) {
			if (XHCI_SUPPORTED_PROTOCOLS_0_MAJOR(eec) == 0x3)
				fPortSpeeds[i] = USB_SPEED_SUPERSPEED;
			else
				fPortSpeeds[i] = USB_SPEED_HIGHSPEED;

			TRACE("speed for port %" B_PRId32 " is %s\n", i,
				fPortSpeeds[i] == USB_SPEED_SUPERSPEED ? "super" : "high");
		}
		portFound += count;
	}

	uint32 params2 = ReadCapReg32(XHCI_HCSPARAMS2);
	fScratchpadCount = HCS_MAX_SC_BUFFERS(params2);
	if (fScratchpadCount > XHCI_MAX_SCRATCHPADS) {
		TRACE_ERROR("invalid number of scratchpads: %" B_PRIu32 "\n",
			fScratchpadCount);
		return B_ERROR;
	}

	uint32 params3 = ReadCapReg32(XHCI_HCSPARAMS3);
	fExitLatMax = HCS_U1_DEVICE_LATENCY(params3)
		+ HCS_U2_DEVICE_LATENCY(params3);

	// clear interrupts & disable device notifications
	WriteOpReg(XHCI_STS, ReadOpReg(XHCI_STS));
	WriteOpReg(XHCI_DNCTRL, 0);

	// allocate Device Context Base Address array
	phys_addr_t dmaAddress;
	fDcbaArea = fStack->AllocateArea((void **)&fDcba, &dmaAddress,
		sizeof(*fDcba), "DCBA Area");
	if (fDcbaArea < B_OK) {
		TRACE_ERROR("unable to create the DCBA area\n");
		return B_ERROR;
	}
	memset(fDcba, 0, sizeof(*fDcba));
	memset(fScratchpadArea, 0, sizeof(fScratchpadArea));
	memset(fScratchpad, 0, sizeof(fScratchpad));

	// setting the first address to the scratchpad array address
	fDcba->baseAddress[0] = dmaAddress
		+ offsetof(struct xhci_device_context_array, scratchpad);

	// fill up the scratchpad array with scratchpad pages
	for (uint32 i = 0; i < fScratchpadCount; i++) {
		phys_addr_t scratchDmaAddress;
		fScratchpadArea[i] = fStack->AllocateArea((void **)&fScratchpad[i],
			&scratchDmaAddress, B_PAGE_SIZE, "Scratchpad Area");
		if (fScratchpadArea[i] < B_OK) {
			TRACE_ERROR("unable to create the scratchpad area\n");
			return B_ERROR;
		}
		fDcba->scratchpad[i] = scratchDmaAddress;
	}

	TRACE("setting DCBAAP %" B_PRIxPHYSADDR "\n", dmaAddress);
	WriteOpReg(XHCI_DCBAAP_LO, (uint32)dmaAddress);
	WriteOpReg(XHCI_DCBAAP_HI, (uint32)(dmaAddress >> 32));

	// allocate Event Ring Segment Table
	uint8 *addr;
	fErstArea = fStack->AllocateArea((void **)&addr, &dmaAddress,
		(XHCI_MAX_COMMANDS + XHCI_MAX_EVENTS) * sizeof(xhci_trb)
		+ sizeof(xhci_erst_element),
		"USB XHCI ERST CMD_RING and EVENT_RING Area");

	if (fErstArea < B_OK) {
		TRACE_ERROR("unable to create the ERST AND RING area\n");
		delete_area(fDcbaArea);
		return B_ERROR;
	}
	fErst = (xhci_erst_element *)addr;
	memset(fErst, 0, (XHCI_MAX_COMMANDS + XHCI_MAX_EVENTS) * sizeof(xhci_trb)
		+ sizeof(xhci_erst_element));

	// fill with Event Ring Segment Base Address and Event Ring Segment Size
	fErst->rs_addr = dmaAddress + sizeof(xhci_erst_element);
	fErst->rs_size = XHCI_MAX_EVENTS;
	fErst->rsvdz = 0;

	addr += sizeof(xhci_erst_element);
	fEventRing = (xhci_trb *)addr;
	addr += XHCI_MAX_EVENTS * sizeof(xhci_trb);
	fCmdRing = (xhci_trb *)addr;

	TRACE("setting ERST size\n");
	WriteRunReg32(XHCI_ERSTSZ(0), XHCI_ERSTS_SET(1));

	TRACE("setting ERDP addr = 0x%" B_PRIx64 "\n", fErst->rs_addr);
	WriteRunReg32(XHCI_ERDP_LO(0), (uint32)fErst->rs_addr);
	WriteRunReg32(XHCI_ERDP_HI(0), (uint32)(fErst->rs_addr >> 32));

	TRACE("setting ERST base addr = 0x%" B_PRIxPHYSADDR "\n", dmaAddress);
	WriteRunReg32(XHCI_ERSTBA_LO(0), (uint32)dmaAddress);
	WriteRunReg32(XHCI_ERSTBA_HI(0), (uint32)(dmaAddress >> 32));

	dmaAddress += sizeof(xhci_erst_element) + XHCI_MAX_EVENTS
		* sizeof(xhci_trb);

	// Make sure the Command Ring is stopped
	if ((ReadOpReg(XHCI_CRCR_LO) & CRCR_CRR) != 0) {
		TRACE_ALWAYS("Command Ring is running, send stop/cancel\n");
		WriteOpReg(XHCI_CRCR_LO, CRCR_CS);
		WriteOpReg(XHCI_CRCR_HI, 0);
		WriteOpReg(XHCI_CRCR_LO, CRCR_CA);
		WriteOpReg(XHCI_CRCR_HI, 0);
		snooze(1000);
		if ((ReadOpReg(XHCI_CRCR_LO) & CRCR_CRR) != 0) {
			TRACE_ERROR("Command Ring still running after stop/cancel\n");
		}
	}
	TRACE("setting CRCR addr = 0x%" B_PRIxPHYSADDR "\n", dmaAddress);
	WriteOpReg(XHCI_CRCR_LO, (uint32)dmaAddress | CRCR_RCS);
	WriteOpReg(XHCI_CRCR_HI, (uint32)(dmaAddress >> 32));
	// link trb
	fCmdRing[XHCI_MAX_COMMANDS - 1].address = dmaAddress;

	TRACE("setting interrupt rate\n");

	// Setting IMOD below 0x3F8 on Intel Lynx Point can cause IRQ lockups
	if (fPCIInfo->vendor_id == PCI_VENDOR_INTEL
		&& (fPCIInfo->device_id == PCI_DEVICE_INTEL_PANTHER_POINT_XHCI
			|| fPCIInfo->device_id == PCI_DEVICE_INTEL_LYNX_POINT_XHCI
			|| fPCIInfo->device_id == PCI_DEVICE_INTEL_LYNX_POINT_LP_XHCI
			|| fPCIInfo->device_id == PCI_DEVICE_INTEL_BAYTRAIL_XHCI
			|| fPCIInfo->device_id == PCI_DEVICE_INTEL_WILDCAT_POINT_XHCI)) {
		WriteRunReg32(XHCI_IMOD(0), 0x000003f8); // 4000 irq/s
	} else {
		WriteRunReg32(XHCI_IMOD(0), 0x000001f4); // 8000 irq/s
	}

	TRACE("enabling interrupt\n");
	WriteRunReg32(XHCI_IMAN(0), ReadRunReg32(XHCI_IMAN(0)) | IMAN_INTR_ENA);

	WriteOpReg(XHCI_CMD, CMD_RUN | CMD_INTE | CMD_HSEE);

	// wait for start up state
	if (WaitOpBits(XHCI_STS, STS_HCH, 0) != B_OK) {
		TRACE_ERROR("HCH start up timeout\n");
	}

	fRootHub = new(std::nothrow) XHCIRootHub(RootObject(), 1);
	if (!fRootHub) {
		TRACE_ERROR("no memory to allocate root hub\n");
		return B_NO_MEMORY;
	}

	if (fRootHub->InitCheck() < B_OK) {
		TRACE_ERROR("root hub failed init check\n");
		return fRootHub->InitCheck();
	}

	SetRootHub(fRootHub);

	fRootHub->RegisterNode(Node());

	TRACE_ALWAYS("successfully started the controller\n");

#ifdef TRACE_USB
	TRACE("No-Op test...\n");
	Noop();
#endif

	return BusManager::Start();
}


status_t
XHCI::SubmitTransfer(Transfer *transfer)
{
	// short circuit the root hub
	if (transfer->TransferPipe()->DeviceAddress() == 1)
		return fRootHub->ProcessTransfer(this, transfer);

	TRACE("SubmitTransfer(%p)\n", transfer);
	Pipe *pipe = transfer->TransferPipe();
	if ((pipe->Type() & USB_OBJECT_CONTROL_PIPE) != 0)
		return SubmitControlRequest(transfer);
	return SubmitNormalRequest(transfer);
}


status_t
XHCI::SubmitControlRequest(Transfer *transfer)
{
	Pipe *pipe = transfer->TransferPipe();
	usb_request_data *requestData = transfer->RequestData();
	bool directionIn = (requestData->RequestType & USB_REQTYPE_DEVICE_IN) != 0;

	TRACE("SubmitControlRequest() length %d\n", requestData->Length);

	xhci_endpoint *endpoint = (xhci_endpoint *)pipe->ControllerCookie();
	if (endpoint == NULL) {
		TRACE_ERROR("control pipe has no endpoint!\n");
		return B_BAD_VALUE;
	}
	if (endpoint->device == NULL) {
		panic("endpoint is not initialized!");
		return B_NO_INIT;
	}

	if (transfer->IsPhysical()) {
		// We don't handle this case.
		return B_NOT_SUPPORTED;
	}

	status_t status = transfer->InitKernelAccess();
	if (status != B_OK)
		return status;

	xhci_td *descriptor = CreateDescriptor(3, 1, requestData->Length);
	if (descriptor == NULL)
		return B_NO_MEMORY;
	descriptor->transfer = transfer;

	// Setup Stage
	uint8 index = 0;
	memcpy(&descriptor->trbs[index].address, requestData,
		sizeof(usb_request_data));
	descriptor->trbs[index].status = TRB_2_IRQ(0) | TRB_2_BYTES(8);
	descriptor->trbs[index].flags
		= TRB_3_TYPE(TRB_TYPE_SETUP_STAGE) | TRB_3_IDT_BIT | TRB_3_CYCLE_BIT;
	if (requestData->Length > 0) {
		descriptor->trbs[index].flags |=
			directionIn ? TRB_3_TRT_IN : TRB_3_TRT_OUT;
	}

	index++;

	// Data Stage (if any)
	if (requestData->Length > 0) {
		descriptor->trbs[index].address = descriptor->buffer_addrs[0];
		descriptor->trbs[index].status = TRB_2_IRQ(0)
			| TRB_2_BYTES(requestData->Length)
			| TRB_2_TD_SIZE(0);
		descriptor->trbs[index].flags = TRB_3_TYPE(TRB_TYPE_DATA_STAGE)
			| (directionIn ? TRB_3_DIR_IN : 0)
			| TRB_3_CYCLE_BIT;

		if (!directionIn) {
			transfer->PrepareKernelAccess();
			memcpy(descriptor->buffers[0],
				(uint8 *)transfer->Vector()[0].base, requestData->Length);
		}

		index++;
	}

	// Status Stage
	descriptor->trbs[index].address = 0;
	descriptor->trbs[index].status = TRB_2_IRQ(0);
	descriptor->trbs[index].flags = TRB_3_TYPE(TRB_TYPE_STATUS_STAGE)
			| TRB_3_CHAIN_BIT | TRB_3_ENT_BIT | TRB_3_CYCLE_BIT;
		// The CHAIN bit must be set when using an Event Data TRB
		// (XHCI 1.2 § 6.4.1.2.3 Table 6-31 p472).

	// Status Stage is an OUT transfer when the device is sending data
	// (XHCI 1.2 § 4.11.2.2 Table 4-7 p213), otherwise set the IN bit.
	if (requestData->Length == 0 || !directionIn)
		descriptor->trbs[index].flags |= TRB_3_DIR_IN;

	descriptor->trb_used = index + 1;

	status = _LinkDescriptorForPipe(descriptor, endpoint);
	if (status != B_OK) {
		FreeDescriptor(descriptor);
		return status;
	}

	return B_OK;
}


status_t
XHCI::SubmitNormalRequest(Transfer *transfer)
{
	TRACE("SubmitNormalRequest() length %" B_PRIuSIZE "\n", transfer->FragmentLength());

	Pipe *pipe = transfer->TransferPipe();
	usb_isochronous_data *isochronousData = transfer->IsochronousData();
	bool directionIn = (pipe->Direction() == Pipe::In);

	xhci_endpoint *endpoint = (xhci_endpoint *)pipe->ControllerCookie();
	if (endpoint == NULL) {
		TRACE_ERROR("pipe has no endpoint!\n");
		return B_BAD_VALUE;
	}
	if (endpoint->device == NULL) {
		panic("endpoint is not initialized!");
		return B_NO_INIT;
	}

	status_t status = transfer->InitKernelAccess();
	if (status != B_OK)
		return status;

	// TRBs within a TD must be "grouped" into TD Fragments, which mostly means
	// that a max_burst_payload boundary cannot be crossed within a TRB, but
	// only between TRBs. More than one TRB can be in a TD Fragment, but we keep
	// things simple by setting trbSize to the MBP. (XHCI 1.2 § 4.11.7.1 p235.)
	size_t trbSize = endpoint->max_burst_payload;

	if (isochronousData != NULL) {
		if (isochronousData->packet_count == 0)
			return B_BAD_VALUE;

		// Isochronous transfers use more specifically sized packets.
		trbSize = transfer->DataLength() / isochronousData->packet_count;
		if (trbSize == 0 || trbSize > pipe->MaxPacketSize() || trbSize
				!= (size_t)isochronousData->packet_descriptors[0].request_length)
			return B_BAD_VALUE;
	}

	// Now that we know trbSize, compute the count.
	int32 trbCount = (transfer->FragmentLength() + trbSize - 1) / trbSize;

	generic_io_vec* transferVec = transfer->Vector();
	generic_size_t transferVecOffset = 0;
	if (transfer->IsPhysical()) {
		trbSize = 0;
		trbCount = 0;

		for (size_t i = 0; i < transfer->VectorCount(); i++) {
			// There's an XHCI context parameter to indicate if the controller is
			// 64-bit capable, but for consistency we require 32-bit DMA.
			if ((transferVec[i].base + transferVec[i].length) > UINT32_MAX)
				return B_BAD_VALUE;

			trbCount += (transferVec[i].length + endpoint->max_burst_payload - 1)
				/ endpoint->max_burst_payload;
		}
	}

	xhci_td *td = CreateDescriptor(trbCount, trbCount, trbSize);
	if (td == NULL)
		return B_NO_MEMORY;

	// Normal Stage
	const size_t maxPacketSize = pipe->MaxPacketSize();
	size_t remaining = transfer->FragmentLength();
	for (int32 i = 0; i < trbCount; i++) {
		phys_addr_t address;
		generic_size_t trbLength;
		if (!transfer->IsPhysical()) {
			 address = td->buffer_addrs[i];
			 trbLength = (remaining < trbSize) ? remaining : trbSize;
		} else {
			address = transferVec->base + transferVecOffset;
			trbLength = transferVec->length - transferVecOffset;
			if (trbLength > endpoint->max_burst_payload)
				trbLength = endpoint->max_burst_payload;

			transferVecOffset += trbLength;
			if (transferVecOffset == transferVec->length) {
				transferVec++;
				transferVecOffset = 0;
			}
		}

		remaining -= trbLength;

		// The "TD Size" field of a transfer TRB indicates the number of
		// remaining maximum-size *packets* in this TD, *not* including the
		// packets in the current TRB, and capped at 31 if there are more
		// than 31 packets remaining in the TD. (XHCI 1.2 § 4.11.2.4 p218.)
		int32 tdSize = (remaining + maxPacketSize - 1) / maxPacketSize;
		if (tdSize > 31)
			tdSize = 31;

		td->trbs[i].address = address;
		td->trbs[i].status = TRB_2_IRQ(0)
			| TRB_2_BYTES(trbLength)
			| TRB_2_TD_SIZE(tdSize);
		td->trbs[i].flags = TRB_3_TYPE(TRB_TYPE_NORMAL)
			| TRB_3_CYCLE_BIT | TRB_3_CHAIN_BIT;

		td->trb_used++;
	}

	// Isochronous-specific.
	if (isochronousData != NULL) {
		// This is an isochronous transfer; it should have one TD per packet.
		for (uint32 i = 0; i < isochronousData->packet_count; i++) {
			td->trbs[i].flags &= ~(TRB_3_TYPE(TRB_TYPE_NORMAL));
			td->trbs[i].flags |= TRB_3_TYPE(TRB_TYPE_ISOCH);

			if (i != (isochronousData->packet_count - 1)) {
				// For all but the last TD, generate events (but not interrupts) on short packets.
				// (The last TD uses the regular Event Data TRB.)
				td->trbs[i].flags |= TRB_3_ISP_BIT | TRB_3_BEI_BIT;
				td->trbs[i].flags &= ~TRB_3_CHAIN_BIT;
			}
		}

		// TODO: We do not currently take Mult into account at all!
		// How are we supposed to do that here?

		// Determine the (starting) frame number: if ISO_ASAP is set,
		// we are queueing this "right away", and so want to reset
		// the starting_frame_number. Otherwise we use the passed one.
		uint32 frame;
		if ((isochronousData->flags & USB_ISO_ASAP) != 0
				|| isochronousData->starting_frame_number == NULL) {
			// All reads from the microframe index register must be
			// incremented by 1. (XHCI 1.2 § 4.14.2.1.4 p265.)
			frame = (ReadRunReg32(XHCI_MFINDEX) + 1) >> 3;
			td->trbs[0].flags |= TRB_3_ISO_SIA_BIT;
		} else {
			frame = *isochronousData->starting_frame_number;
			td->trbs[0].flags |= TRB_3_FRID(frame);
		}
		if (isochronousData->starting_frame_number != NULL)
			*isochronousData->starting_frame_number = frame;
	}

	// Set the ENT (Evaluate Next TRB) bit, so that the HC will not switch
	// contexts before evaluating the Link TRB that _LinkDescriptorForPipe
	// will insert, as otherwise there would be a race between us freeing
	// and unlinking the descriptor, and the controller evaluating the Link TRB
	// and thus getting back onto the main ring and executing the Event Data
	// TRB that generates the interrupt for this transfer.
	//
	// Note that we *do not* unset the CHAIN bit in this TRB, thus including
	// the Link TRB in this TD formally, which is required when using the
	// ENT bit. (XHCI 1.2 § 4.12.3 p250.)
	td->trbs[td->trb_used - 1].flags |= TRB_3_ENT_BIT;

	if (!directionIn && !transfer->IsPhysical()) {
		TRACE("copying out iov count %ld\n", transfer->VectorCount());
		status_t status = transfer->PrepareKernelAccess();
		if (status != B_OK) {
			FreeDescriptor(td);
			return status;
		}
		WriteDescriptor(td, transfer->Vector(),
			transfer->VectorCount(), transfer->IsPhysical());
	}

	td->transfer = transfer;
	status = _LinkDescriptorForPipe(td, endpoint);
	if (status != B_OK) {
		FreeDescriptor(td);
		return status;
	}

	return B_OK;
}


status_t
XHCI::CancelQueuedTransfers(Pipe *pipe, bool force)
{
	xhci_endpoint* endpoint = (xhci_endpoint*)pipe->ControllerCookie();
	if (endpoint == NULL || endpoint->trbs == NULL) {
		// Someone's de-allocated this pipe or endpoint in the meantime.
		// (Possibly AllocateDevice failed, and we were the temporary pipe.)
		return B_NO_INIT;
	}

#ifndef TRACE_USB
	if (force)
#endif
	{
		TRACE_ALWAYS("cancel queued transfers (%" B_PRId8 ") for pipe %p (%d)\n",
			endpoint->used, pipe, pipe->EndpointAddress());
	}

	MutexLocker endpointLocker(endpoint->lock);

	if (endpoint->td_head == NULL) {
		// There aren't any currently pending transfers to cancel.
		return B_OK;
	}

	// Calling the callbacks while holding the endpoint lock could potentially
	// cause deadlocks, so we instead store them in a pointer array. We need
	// to do this separately from freeing the TDs, for in the case we fail
	// to stop the endpoint, we cancel the transfers but do not free the TDs.
	Transfer* transfers[XHCI_MAX_TRANSFERS];
	int32 transfersCount = 0;

	for (xhci_td* td = endpoint->td_head; td != NULL; td = td->next) {
		if (td->transfer == NULL)
			continue;

		transfers[transfersCount] = td->transfer;
		transfersCount++;
		td->transfer = NULL;
	}

	// It is possible that while waiting for the stop-endpoint command to
	// complete, one of the queued transfers posts a completion event, so in
	// order to avoid a deadlock, we must unlock the endpoint.
	endpointLocker.Unlock();
	status_t status = StopEndpoint(false, endpoint);
	if (status != B_OK && status != B_DEV_STALLED) {
		// It is possible that the endpoint was stopped by the controller at the
		// same time our STOP command was in progress, causing a "Context State"
		// error. In that case, try again; if the endpoint is already stopped,
		// StopEndpoint will notice this. (XHCI 1.2 § 4.6.9 p137.)
		status = StopEndpoint(false, endpoint);
	}
	if (status == B_DEV_STALLED) {
		// Only exit from a Halted state is a RESET. (XHCI 1.2 § 4.8.3 p163.)
		TRACE_ERROR("cancel queued transfers: halted endpoint, reset!\n");
		status = ResetEndpoint(false, endpoint);
	}
	endpointLocker.Lock();

	// Detach the head TD from the endpoint.
	xhci_td* td_head = endpoint->td_head;
	endpoint->td_head = NULL;

	if (status == B_OK) {
		// Clear the endpoint's TRBs.
		memset(endpoint->trbs, 0, sizeof(xhci_trb) * XHCI_ENDPOINT_RING_SIZE);
		endpoint->used = 0;
		endpoint->next = 0;

		// Set dequeue pointer location to the beginning of the ring.
		SetTRDequeue(endpoint->trb_addr, 0, endpoint->id + 1,
			endpoint->device->slot);

		// We don't need to do anything else to restart the ring, as it will resume
		// operation as normal upon the next doorbell. (XHCI 1.2 § 4.6.9 p136.)
	} else {
		// We couldn't stop the endpoint. Most likely the device has been
		// removed and the endpoint was stopped by the hardware, or is
		// for some reason busy and cannot be stopped.
		TRACE_ERROR("cancel queued transfers: could not stop endpoint: %s!\n",
			strerror(status));

		// Instead of freeing the TDs, we want to leave them in the endpoint
		// so that when/if the hardware returns, they can be properly unlinked,
		// as otherwise the endpoint could get "stuck" by having the "used"
		// slowly accumulate due to "dead" transfers.
		endpoint->td_head = td_head;
		td_head = NULL;
	}

	endpointLocker.Unlock();

	for (int32 i = 0; i < transfersCount; i++) {
		// If the transfer is canceled by force, the one causing the
		// cancel is possibly not the one who initiated the transfer
		// and the callback is likely not safe anymore.
		if (!force)
			transfers[i]->Finished(B_CANCELED, 0);

		delete transfers[i];
	}

	// This loop looks a bit strange because we need to store the "next"
	// pointer before freeing the descriptor.
	xhci_td* td;
	while ((td = td_head) != NULL) {
		td_head = td_head->next;
		FreeDescriptor(td);
	}

	return B_OK;
}


status_t
XHCI::StartDebugTransfer(Transfer *transfer)
{
	Pipe *pipe = transfer->TransferPipe();
	xhci_endpoint *endpoint = (xhci_endpoint *)pipe->ControllerCookie();
	if (endpoint == NULL)
		return B_BAD_VALUE;

	// Check all locks that we are going to hit when running transfers.
	if (mutex_trylock(&endpoint->lock) != B_OK)
		return B_WOULD_BLOCK;
	if (mutex_trylock(&fFinishedLock) != B_OK) {
		mutex_unlock(&endpoint->lock);
		return B_WOULD_BLOCK;
	}
	if (mutex_trylock(&fEventLock) != B_OK) {
		mutex_unlock(&endpoint->lock);
		mutex_unlock(&fFinishedLock);
		return B_WOULD_BLOCK;
	}
	mutex_unlock(&endpoint->lock);
	mutex_unlock(&fFinishedLock);
	mutex_unlock(&fEventLock);

	status_t status = SubmitTransfer(transfer);
	if (status != B_OK)
		return status;

	// The endpoint's head TD is the TD of the just-submitted transfer.
	// Just like EHCI, abuse the callback cookie to hold the TD pointer.
	transfer->SetCallback(NULL, endpoint->td_head);

	return B_OK;
}


status_t
XHCI::CheckDebugTransfer(Transfer *transfer)
{
	xhci_td *transfer_td = (xhci_td *)transfer->CallbackCookie();
	if (transfer_td == NULL)
		return B_NO_INIT;

	// Process events once, and then look for it in the finished list.
	ProcessEvents();
	xhci_td *previous = NULL;
	for (xhci_td *td = fFinishedHead; td != NULL; td = td->next) {
		if (td != transfer_td) {
			previous = td;
			continue;
		}

		// We've found it!
		if (previous == NULL) {
			fFinishedHead = fFinishedHead->next;
		} else {
			previous->next = td->next;
		}

		bool directionIn = (transfer->TransferPipe()->Direction() != Pipe::Out);
		status_t status = (td->trb_completion_code == COMP_SUCCESS
			|| td->trb_completion_code == COMP_SHORT_PACKET) ? B_OK : B_ERROR;

		if (status == B_OK && directionIn && !transfer->IsPhysical()) {
			ReadDescriptor(td, transfer->Vector(), transfer->VectorCount(),
				transfer->IsPhysical());
		}

		FreeDescriptor(td);
		transfer->SetCallback(NULL, NULL);
		return status;
	}

	// We didn't find it.
	spin(75);
	return B_DEV_PENDING;
}


void
XHCI::CancelDebugTransfer(Transfer *transfer)
{
	while (CheckDebugTransfer(transfer) == B_DEV_PENDING)
		spin(100);
}


status_t
XHCI::NotifyPipeChange(Pipe *pipe, usb_change change)
{
	TRACE("pipe change %d for pipe %p (%d)\n", change, pipe,
		pipe->EndpointAddress());

	switch (change) {
	case USB_CHANGE_CREATED:
		return _InsertEndpointForPipe(pipe);
	case USB_CHANGE_DESTROYED:
		return _RemoveEndpointForPipe(pipe);

	case USB_CHANGE_PIPE_POLICY_CHANGED:
		// We don't care about these, at least for now.
		return B_OK;
	}

	TRACE_ERROR("unknown pipe change!\n");
	return B_UNSUPPORTED;
}


xhci_td *
XHCI::CreateDescriptor(uint32 trbCount, uint32 bufferCount, size_t bufferSize)
{
	const bool inKDL = debug_debugger_running();

	xhci_td *result;
	if (!inKDL) {
		result = (xhci_td*)calloc(1, sizeof(xhci_td));
	} else {
		// Just use the physical memory allocator while in KDL; it's less
		// secure than using the regular heap, but it's easier to deal with.
		phys_addr_t dummy;
		fStack->AllocateChunk((void **)&result, &dummy, sizeof(xhci_td));
	}

	if (result == NULL) {
		TRACE_ERROR("failed to allocate a transfer descriptor\n");
		return NULL;
	}

	// We always allocate 1 more TRB than requested, so that
	// _LinkDescriptorForPipe() has room to insert a link TRB.
	trbCount++;
	if (fStack->AllocateChunk((void **)&result->trbs, &result->trb_addr,
			(trbCount * sizeof(xhci_trb))) < B_OK) {
		TRACE_ERROR("failed to allocate TRBs\n");
		FreeDescriptor(result);
		return NULL;
	}
	result->trb_count = trbCount;
	result->trb_used = 0;

	if (bufferSize > 0) {
		// Due to how the USB stack allocates physical memory, we can't just
		// request one large chunk the size of the transfer, and so instead we
		// create a series of buffers as requested by our caller.

		// We store the buffer pointers and addresses in one memory block.
		if (!inKDL) {
			result->buffers = (void**)calloc(bufferCount,
				(sizeof(void*) + sizeof(phys_addr_t)));
		} else {
			phys_addr_t dummy;
			fStack->AllocateChunk((void **)&result->buffers, &dummy,
				bufferCount * (sizeof(void*) + sizeof(phys_addr_t)));
		}
		if (result->buffers == NULL) {
			TRACE_ERROR("unable to allocate space for buffer infos\n");
			FreeDescriptor(result);
			return NULL;
		}
		result->buffer_addrs = (phys_addr_t*)&result->buffers[bufferCount];
		result->buffer_size = bufferSize;
		result->buffer_count = bufferCount;

		// Optimization: If the requested total size of all buffers is less
		// than 32*B_PAGE_SIZE (the maximum size that the physical memory
		// allocator can handle), we allocate only one buffer and segment it.
		size_t totalSize = bufferSize * bufferCount;
		if (totalSize < (32 * B_PAGE_SIZE)) {
			if (fStack->AllocateChunk(&result->buffers[0],
					&result->buffer_addrs[0], totalSize) < B_OK) {
				TRACE_ERROR("unable to allocate space for large buffer (size %ld)\n",
					totalSize);
				FreeDescriptor(result);
				return NULL;
			}
			for (uint32 i = 1; i < bufferCount; i++) {
				result->buffers[i] = (void*)((addr_t)(result->buffers[i - 1])
					+ bufferSize);
				result->buffer_addrs[i] = result->buffer_addrs[i - 1]
					+ bufferSize;
			}
		} else {
			// Otherwise, we allocate each buffer individually.
			for (uint32 i = 0; i < bufferCount; i++) {
				if (fStack->AllocateChunk(&result->buffers[i],
						&result->buffer_addrs[i], bufferSize) < B_OK) {
					TRACE_ERROR("unable to allocate space for a buffer (size "
						"%" B_PRIuSIZE ", count %" B_PRIu32 ")\n",
						bufferSize, bufferCount);
					FreeDescriptor(result);
					return NULL;
				}
			}
		}
	} else {
		result->buffers = NULL;
		result->buffer_addrs = NULL;
	}

	// Initialize all other fields.
	result->transfer = NULL;
	result->trb_completion_code = 0;
	result->trb_left = 0;
	result->next = NULL;

	TRACE("CreateDescriptor allocated %p, buffer_size %ld, buffer_count %" B_PRIu32 "\n",
		result, result->buffer_size, result->buffer_count);

	return result;
}


void
XHCI::FreeDescriptor(xhci_td *descriptor)
{
	if (descriptor == NULL)
		return;

	const bool inKDL = debug_debugger_running();

	if (descriptor->trbs != NULL) {
		fStack->FreeChunk(descriptor->trbs, descriptor->trb_addr,
			(descriptor->trb_count * sizeof(xhci_trb)));
	}
	if (descriptor->buffers != NULL) {
		size_t totalSize = descriptor->buffer_size * descriptor->buffer_count;
		if (totalSize < (32 * B_PAGE_SIZE)) {
			// This was allocated as one contiguous buffer.
			fStack->FreeChunk(descriptor->buffers[0], descriptor->buffer_addrs[0],
				totalSize);
		} else {
			for (uint32 i = 0; i < descriptor->buffer_count; i++) {
				if (descriptor->buffers[i] == NULL)
					continue;
				fStack->FreeChunk(descriptor->buffers[i], descriptor->buffer_addrs[i],
					descriptor->buffer_size);
			}
		}

		if (!inKDL) {
			free(descriptor->buffers);
		} else {
			fStack->FreeChunk(descriptor->buffers, 0,
				descriptor->buffer_count * (sizeof(void*) + sizeof(phys_addr_t)));
		}
	}

	if (!inKDL)
		free(descriptor);
	else
		fStack->FreeChunk(descriptor, 0, sizeof(xhci_td));
}


size_t
XHCI::WriteDescriptor(xhci_td *descriptor, generic_io_vec *vector, size_t vectorCount, bool physical)
{
	size_t written = 0;

	size_t bufIdx = 0, bufUsed = 0;
	for (size_t vecIdx = 0; vecIdx < vectorCount; vecIdx++) {
		size_t length = vector[vecIdx].length;

		while (length > 0 && bufIdx < descriptor->buffer_count) {
			size_t toCopy = min_c(length, descriptor->buffer_size - bufUsed);
			status_t status = generic_memcpy(
				(generic_addr_t)descriptor->buffers[bufIdx] + bufUsed, false,
				vector[vecIdx].base + (vector[vecIdx].length - length), physical,
				toCopy);
			ASSERT_ALWAYS(status == B_OK);

			written += toCopy;
			bufUsed += toCopy;
			length -= toCopy;
			if (bufUsed == descriptor->buffer_size) {
				bufIdx++;
				bufUsed = 0;
			}
		}
	}

	TRACE("wrote descriptor (%" B_PRIuSIZE " bytes)\n", written);
	return written;
}


size_t
XHCI::ReadDescriptor(xhci_td *descriptor, generic_io_vec *vector, size_t vectorCount, bool physical)
{
	size_t read = 0;

	size_t bufIdx = 0, bufUsed = 0;
	for (size_t vecIdx = 0; vecIdx < vectorCount; vecIdx++) {
		size_t length = vector[vecIdx].length;

		while (length > 0 && bufIdx < descriptor->buffer_count) {
			size_t toCopy = min_c(length, descriptor->buffer_size - bufUsed);
			status_t status = generic_memcpy(
				vector[vecIdx].base + (vector[vecIdx].length - length), physical,
				(generic_addr_t)descriptor->buffers[bufIdx] + bufUsed, false, toCopy);
			ASSERT_ALWAYS(status == B_OK);

			read += toCopy;
			bufUsed += toCopy;
			length -= toCopy;
			if (bufUsed == descriptor->buffer_size) {
				bufIdx++;
				bufUsed = 0;
			}
		}
	}

	TRACE("read descriptor (%" B_PRIuSIZE " bytes)\n", read);
	return read;
}


Device *
XHCI::AllocateDevice(Hub *parent, int8 hubAddress, uint8 hubPort,
	usb_speed speed)
{
	TRACE("AllocateDevice hubAddress %d hubPort %d speed %d\n", hubAddress,
		hubPort, speed);

	uint8 slot = XHCI_MAX_SLOTS;
	status_t status = EnableSlot(&slot);
	if (status != B_OK) {
		TRACE_ERROR("failed to enable slot: %s\n", strerror(status));
		return NULL;
	}

	if (slot == 0 || slot > fSlotCount) {
		TRACE_ERROR("AllocateDevice: bad slot\n");
		return NULL;
	}

	if (fDevices[slot].slot != 0) {
		TRACE_ERROR("AllocateDevice: slot already used\n");
		return NULL;
	}

	struct xhci_device *device = &fDevices[slot];
	device->slot = slot;

	device->input_ctx_area = fStack->AllocateArea((void **)&device->input_ctx,
		&device->input_ctx_addr, sizeof(*device->input_ctx) << fContextSizeShift,
		"XHCI input context");
	if (device->input_ctx_area < B_OK) {
		TRACE_ERROR("unable to create a input context area\n");
		CleanupDevice(device);
		return NULL;
	}
	if (fContextSizeShift == 1) {
		// 64-byte contexts have to be page-aligned in order for
		// _OffsetContextAddr to function properly.
		ASSERT((((addr_t)device->input_ctx) % B_PAGE_SIZE) == 0);
	}

	memset(device->input_ctx, 0, sizeof(*device->input_ctx) << fContextSizeShift);
	_WriteContext(&device->input_ctx->input.dropFlags, 0);
	_WriteContext(&device->input_ctx->input.addFlags, 3);

	uint8 rhPort = hubPort;
	uint32 route = 0;
	for (Device *hubDevice = parent; hubDevice != RootObject();
			hubDevice = (Device *)hubDevice->Parent()) {
		if (hubDevice->Parent() == RootObject())
			break;

		if (rhPort > 15)
			rhPort = 15;
		route = route << 4;
		route |= rhPort;

		rhPort = hubDevice->HubPort();
	}

	uint32 dwslot0 = SLOT_0_NUM_ENTRIES(1) | SLOT_0_ROUTE(route);

	// Get speed of port, only if device connected to root hub port
	// else we have to rely on value reported by the Hub Explore thread
	if (route == 0) {
		GetPortSpeed(hubPort - 1, &speed);
		TRACE("speed updated %d\n", speed);
	}

	// add the speed
	switch (speed) {
	case USB_SPEED_LOWSPEED:
		dwslot0 |= SLOT_0_SPEED(2);
		break;
	case USB_SPEED_FULLSPEED:
		dwslot0 |= SLOT_0_SPEED(1);
		break;
	case USB_SPEED_HIGHSPEED:
		dwslot0 |= SLOT_0_SPEED(3);
		break;
	case USB_SPEED_SUPERSPEED:
		dwslot0 |= SLOT_0_SPEED(4);
		break;
	case USB_SPEED_SUPERSPEEDPLUS:
		dwslot0 |= SLOT_0_SPEED(5);
		break;
	default:
		TRACE_ERROR("unknown usb speed\n");
		break;
	}

	_WriteContext(&device->input_ctx->slot.dwslot0, dwslot0);
	// TODO enable power save
	_WriteContext(&device->input_ctx->slot.dwslot1, SLOT_1_RH_PORT(rhPort));
	uint32 dwslot2 = SLOT_2_IRQ_TARGET(0);

	// If LS/FS device connected to non-root HS device
	if (route != 0 && parent->Speed() == USB_SPEED_HIGHSPEED
		&& (speed == USB_SPEED_LOWSPEED || speed == USB_SPEED_FULLSPEED)) {
		struct xhci_device *parenthub = (struct xhci_device *)
			parent->ControllerCookie();
		dwslot2 |= SLOT_2_PORT_NUM(hubPort);
		dwslot2 |= SLOT_2_TT_HUB_SLOT(parenthub->slot);
	}

	_WriteContext(&device->input_ctx->slot.dwslot2, dwslot2);

	_WriteContext(&device->input_ctx->slot.dwslot3, SLOT_3_SLOT_STATE(0)
		| SLOT_3_DEVICE_ADDRESS(0));

	TRACE("slot 0x%08" B_PRIx32 " 0x%08" B_PRIx32 " 0x%08" B_PRIx32 " 0x%08" B_PRIx32
		"\n", _ReadContext(&device->input_ctx->slot.dwslot0),
		_ReadContext(&device->input_ctx->slot.dwslot1),
		_ReadContext(&device->input_ctx->slot.dwslot2),
		_ReadContext(&device->input_ctx->slot.dwslot3));

	device->device_ctx_area = fStack->AllocateArea((void **)&device->device_ctx,
		&device->device_ctx_addr, sizeof(*device->device_ctx) << fContextSizeShift,
		"XHCI device context");
	if (device->device_ctx_area < B_OK) {
		TRACE_ERROR("unable to create a device context area\n");
		CleanupDevice(device);
		return NULL;
	}
	memset(device->device_ctx, 0, sizeof(*device->device_ctx) << fContextSizeShift);

	device->trb_area = fStack->AllocateArea((void **)&device->trbs,
		&device->trb_addr, sizeof(xhci_trb) * (XHCI_MAX_ENDPOINTS - 1)
			* XHCI_ENDPOINT_RING_SIZE, "XHCI endpoint trbs");
	if (device->trb_area < B_OK) {
		TRACE_ERROR("unable to create a device trbs area\n");
		CleanupDevice(device);
		return NULL;
	}

	// set up slot pointer to device context
	fDcba->baseAddress[slot] = device->device_ctx_addr;

	size_t maxPacketSize;
	switch (speed) {
	case USB_SPEED_LOWSPEED:
	case USB_SPEED_FULLSPEED:
		maxPacketSize = 8;
		break;
	case USB_SPEED_HIGHSPEED:
		maxPacketSize = 64;
		break;
	default:
		maxPacketSize = 512;
		break;
	}

	xhci_endpoint* endpoint0 = &device->endpoints[0];
	mutex_init(&endpoint0->lock, "xhci endpoint lock");
	endpoint0->device = device;
	endpoint0->id = 0;
	endpoint0->status = 0;
	endpoint0->td_head = NULL;
	endpoint0->used = 0;
	endpoint0->next = 0;
	endpoint0->trbs = device->trbs;
	endpoint0->trb_addr = device->trb_addr;

	// configure the Control endpoint 0
	if (ConfigureEndpoint(endpoint0, slot, 0, USB_OBJECT_CONTROL_PIPE, false,
			0, maxPacketSize, speed, 0, 0) != B_OK) {
		TRACE_ERROR("unable to configure default control endpoint\n");
		CleanupDevice(device);
		return NULL;
	}

	// device should get to addressed state (bsr = 0)
	status = SetAddress(device->input_ctx_addr, false, slot);
	if (status != B_OK) {
		TRACE_ERROR("unable to set address: %s\n", strerror(status));
		CleanupDevice(device);
		return NULL;
	}

	device->address = SLOT_3_DEVICE_ADDRESS_GET(_ReadContext(
		&device->device_ctx->slot.dwslot3));

	TRACE("device: address 0x%x state 0x%08" B_PRIx32 "\n", device->address,
		SLOT_3_SLOT_STATE_GET(_ReadContext(
			&device->device_ctx->slot.dwslot3)));
	TRACE("endpoint0 state 0x%08" B_PRIx32 "\n",
		ENDPOINT_0_STATE_GET(_ReadContext(
			&device->device_ctx->endpoints[0].dwendpoint0)));

	// Wait a bit for the device to complete addressing
	snooze(USB_DELAY_SET_ADDRESS);

	// Create a temporary pipe with the new address
	ControlPipe pipe(parent);
	pipe.SetControllerCookie(endpoint0);
	pipe.InitCommon(device->address + 1, 0, speed, Pipe::Default, maxPacketSize, 0,
		hubAddress, hubPort);

	// Get the device descriptor
	// Just retrieve the first 8 bytes of the descriptor -> minimum supported
	// size of any device. It is enough because it includes the device type.

	size_t actualLength = 0;
	usb_device_descriptor deviceDescriptor;

	TRACE("getting the device descriptor\n");
	status = pipe.SendRequest(
		USB_REQTYPE_DEVICE_IN | USB_REQTYPE_STANDARD,		// type
		USB_REQUEST_GET_DESCRIPTOR,							// request
		USB_DESCRIPTOR_DEVICE << 8,							// value
		0,													// index
		8,													// length
		(void *)&deviceDescriptor,							// buffer
		8,													// buffer length
		&actualLength);										// actual length

	if (actualLength != 8) {
		TRACE_ERROR("failed to get the device descriptor: %s\n",
			strerror(status));
		CleanupDevice(device);
		return NULL;
	}

	TRACE("device_class: %d device_subclass %d device_protocol %d\n",
		deviceDescriptor.device_class, deviceDescriptor.device_subclass,
		deviceDescriptor.device_protocol);

	if (speed == USB_SPEED_FULLSPEED && deviceDescriptor.max_packet_size_0 != 8) {
		TRACE("Full speed device with different max packet size for Endpoint 0\n");
		uint32 dwendpoint1 = _ReadContext(
			&device->input_ctx->endpoints[0].dwendpoint1);
		dwendpoint1 &= ~ENDPOINT_1_MAXPACKETSIZE(0xffff);
		dwendpoint1 |= ENDPOINT_1_MAXPACKETSIZE(
			deviceDescriptor.max_packet_size_0);
		_WriteContext(&device->input_ctx->endpoints[0].dwendpoint1,
			dwendpoint1);
		_WriteContext(&device->input_ctx->input.dropFlags, 0);
		_WriteContext(&device->input_ctx->input.addFlags, (1 << 1));
		EvaluateContext(device->input_ctx_addr, device->slot);
	}

	Device *deviceObject = NULL;
	if (deviceDescriptor.device_class == 0x09) {
		TRACE("creating new Hub\n");
		TRACE("getting the hub descriptor\n");
		size_t actualLength = 0;
		usb_hub_descriptor hubDescriptor;
		status = pipe.SendRequest(
			USB_REQTYPE_DEVICE_IN | USB_REQTYPE_CLASS,			// type
			USB_REQUEST_GET_DESCRIPTOR,							// request
			USB_DESCRIPTOR_HUB << 8,							// value
			0,													// index
			sizeof(usb_hub_descriptor),							// length
			(void *)&hubDescriptor,								// buffer
			sizeof(usb_hub_descriptor),							// buffer length
			&actualLength);

		if (actualLength != sizeof(usb_hub_descriptor)) {
			TRACE_ERROR("error while getting the hub descriptor: %s\n",
				strerror(status));
			CleanupDevice(device);
			return NULL;
		}

		uint32 dwslot0 = _ReadContext(&device->input_ctx->slot.dwslot0);
		dwslot0 |= SLOT_0_HUB_BIT;
		_WriteContext(&device->input_ctx->slot.dwslot0, dwslot0);
		uint32 dwslot1 = _ReadContext(&device->input_ctx->slot.dwslot1);
		dwslot1 |= SLOT_1_NUM_PORTS(hubDescriptor.num_ports);
		_WriteContext(&device->input_ctx->slot.dwslot1, dwslot1);
		if (speed == USB_SPEED_HIGHSPEED) {
			uint32 dwslot2 = _ReadContext(&device->input_ctx->slot.dwslot2);
			dwslot2 |= SLOT_2_TT_TIME(HUB_TTT_GET(hubDescriptor.characteristics));
			_WriteContext(&device->input_ctx->slot.dwslot2, dwslot2);
		}

		deviceObject = new(std::nothrow) Hub(parent, hubAddress, hubPort,
			deviceDescriptor, device->address + 1, speed, false, device);
	} else {
		TRACE("creating new device\n");
		deviceObject = new(std::nothrow) Device(parent, hubAddress, hubPort,
			deviceDescriptor, device->address + 1, speed, false, device);
	}
	if (deviceObject == NULL || deviceObject->InitCheck() != B_OK) {
		if (deviceObject == NULL) {
			TRACE_ERROR("no memory to allocate device\n");
		} else {
			TRACE_ERROR("device object failed to initialize\n");
		}
		CleanupDevice(device);
		return NULL;
	}

	// We don't want to disable the default endpoint, naturally, which would
	// otherwise happen when this Pipe object is destroyed.
	pipe.SetControllerCookie(NULL);

	deviceObject->RegisterNode();

	TRACE("AllocateDevice() port %d slot %d\n", hubPort, slot);
	return deviceObject;
}


void
XHCI::FreeDevice(Device *usbDevice)
{
	xhci_device* device = (xhci_device*)usbDevice->ControllerCookie();
	TRACE("FreeDevice() slot %d\n", device->slot);

	// Delete the device first, so it cleans up its pipes and tells us
	// what we need to destroy before we tear down our internal state.
	delete usbDevice;

	CleanupDevice(device);
}


void
XHCI::CleanupDevice(xhci_device *device)
{
	if (device->slot != 0) {
		DisableSlot(device->slot);
		fDcba->baseAddress[device->slot] = 0;
	}

	if (device->trb_addr != 0)
		delete_area(device->trb_area);
	if (device->input_ctx_addr != 0)
		delete_area(device->input_ctx_area);
	if (device->device_ctx_addr != 0)
		delete_area(device->device_ctx_area);

	memset(device, 0, sizeof(xhci_device));
}


uint8
XHCI::_GetEndpointState(xhci_endpoint* endpoint)
{
	struct xhci_device_ctx* device_ctx = endpoint->device->device_ctx;
	return ENDPOINT_0_STATE_GET(
		_ReadContext(&device_ctx->endpoints[endpoint->id].dwendpoint0));
}


status_t
XHCI::_InsertEndpointForPipe(Pipe *pipe)
{
	TRACE("insert endpoint for pipe %p (%d)\n", pipe, pipe->EndpointAddress());

	if (pipe->ControllerCookie() != NULL
			|| pipe->Parent()->Type() != USB_OBJECT_DEVICE) {
		// default pipe is already referenced
		return B_OK;
	}

	Device* usbDevice = (Device *)pipe->Parent();
	if (usbDevice->Parent() == RootObject()) {
		// root hub needs no initialization
		return B_OK;
	}

	struct xhci_device *device = (struct xhci_device *)
		usbDevice->ControllerCookie();
	if (device == NULL) {
		panic("device is NULL\n");
		return B_NO_INIT;
	}

	const uint8 id = (2 * pipe->EndpointAddress()
		+ (pipe->Direction() != Pipe::Out ? 1 : 0)) - 1;
	if (id >= XHCI_MAX_ENDPOINTS - 1)
		return B_BAD_VALUE;

	if (id > 0) {
		uint32 devicedwslot0 = _ReadContext(&device->device_ctx->slot.dwslot0);
		if (SLOT_0_NUM_ENTRIES_GET(devicedwslot0) == 1) {
			uint32 inputdwslot0 = _ReadContext(&device->input_ctx->slot.dwslot0);
			inputdwslot0 &= ~(SLOT_0_NUM_ENTRIES(0x1f));
			inputdwslot0 |= SLOT_0_NUM_ENTRIES(XHCI_MAX_ENDPOINTS - 1);
			_WriteContext(&device->input_ctx->slot.dwslot0, inputdwslot0);
			EvaluateContext(device->input_ctx_addr, device->slot);
		}

		xhci_endpoint* endpoint = &device->endpoints[id];
		mutex_init(&endpoint->lock, "xhci endpoint lock");
		MutexLocker endpointLocker(endpoint->lock);

		endpoint->device = device;
		endpoint->id = id;
		endpoint->td_head = NULL;
		endpoint->used = 0;
		endpoint->next = 0;

		endpoint->trbs = device->trbs + id * XHCI_ENDPOINT_RING_SIZE;
		endpoint->trb_addr = device->trb_addr
			+ id * XHCI_ENDPOINT_RING_SIZE * sizeof(xhci_trb);
		memset(endpoint->trbs, 0,
			sizeof(xhci_trb) * XHCI_ENDPOINT_RING_SIZE);

		TRACE("insert endpoint for pipe: trbs, device %p endpoint %p\n",
			device->trbs, endpoint->trbs);
		TRACE("insert endpoint for pipe: trb_addr, device 0x%" B_PRIxPHYSADDR
			" endpoint 0x%" B_PRIxPHYSADDR "\n", device->trb_addr,
			endpoint->trb_addr);

		const uint8 endpointNum = id + 1;

		status_t status = ConfigureEndpoint(endpoint, device->slot, id, pipe->Type(),
			pipe->Direction() == Pipe::In, pipe->Interval(), pipe->MaxPacketSize(),
			usbDevice->Speed(), pipe->MaxBurst(), pipe->BytesPerInterval());
		if (status != B_OK) {
			TRACE_ERROR("unable to configure endpoint: %s\n", strerror(status));
			return status;
		}

		_WriteContext(&device->input_ctx->input.dropFlags, 0);
		_WriteContext(&device->input_ctx->input.addFlags,
			(1 << endpointNum) | (1 << 0));

		ConfigureEndpoint(device->input_ctx_addr, false, device->slot);

		TRACE("device: address 0x%x state 0x%08" B_PRIx32 "\n",
			device->address, SLOT_3_SLOT_STATE_GET(_ReadContext(
				&device->device_ctx->slot.dwslot3)));
		TRACE("endpoint[0] state 0x%08" B_PRIx32 "\n",
			ENDPOINT_0_STATE_GET(_ReadContext(
				&device->device_ctx->endpoints[0].dwendpoint0)));
		TRACE("endpoint[%d] state 0x%08" B_PRIx32 "\n", id,
			ENDPOINT_0_STATE_GET(_ReadContext(
				&device->device_ctx->endpoints[id].dwendpoint0)));
	}
	pipe->SetControllerCookie(&device->endpoints[id]);

	return B_OK;
}


status_t
XHCI::_RemoveEndpointForPipe(Pipe *pipe)
{
	TRACE("remove endpoint for pipe %p (%d)\n", pipe, pipe->EndpointAddress());

	if (pipe->Parent()->Type() != USB_OBJECT_DEVICE)
		return B_OK;
	Device* usbDevice = (Device *)pipe->Parent();
	if (usbDevice->Parent() == RootObject())
		return B_BAD_VALUE;

	xhci_endpoint *endpoint = (xhci_endpoint *)pipe->ControllerCookie();
	if (endpoint == NULL || endpoint->trbs == NULL)
		return B_NO_INIT;

	pipe->SetControllerCookie(NULL);

	if (endpoint->id > 0) {
		xhci_device *device = endpoint->device;
		uint8 epNumber = endpoint->id + 1;
		StopEndpoint(true, endpoint);

		mutex_lock(&endpoint->lock);

		// See comment in CancelQueuedTransfers.
		xhci_td* td;
		while ((td = endpoint->td_head) != NULL) {
			endpoint->td_head = endpoint->td_head->next;
			FreeDescriptor(td);
		}

		mutex_destroy(&endpoint->lock);
		memset(endpoint, 0, sizeof(xhci_endpoint));

		_WriteContext(&device->input_ctx->input.dropFlags, (1 << epNumber));
		_WriteContext(&device->input_ctx->input.addFlags, (1 << 0));

		// The Deconfigure bit in the Configure Endpoint command indicates
		// that *all* endpoints are to be deconfigured, and not just the ones
		// specified in the context flags. (XHCI 1.2 § 4.6.6 p115.)
		ConfigureEndpoint(device->input_ctx_addr, false, device->slot);
	}

	return B_OK;
}


status_t
XHCI::_LinkDescriptorForPipe(xhci_td *descriptor, xhci_endpoint *endpoint)
{
	TRACE("link descriptor for pipe\n");

	// Use mutex_trylock first, in case we are in KDL.
	MutexLocker endpointLocker(&endpoint->lock, mutex_trylock(&endpoint->lock) == B_OK);

	// "used" refers to the number of currently linked TDs, not the number of
	// used TRBs on the ring (we use 2 TRBs on the ring per transfer.)
	// Furthermore, we have to leave an empty item between the head and tail.
	if (endpoint->used >= (XHCI_MAX_TRANSFERS - 1)) {
		TRACE_ERROR("link descriptor for pipe: max transfers count exceeded\n");
		return B_BAD_VALUE;
	}

	// We do not support queuing other transfers in tandem with a fragmented one.
	if (endpoint->td_head != NULL && endpoint->td_head->transfer != NULL
			&& endpoint->td_head->transfer->IsFragmented()) {
		TRACE_ERROR("cannot submit transfer: a fragmented transfer is queued\n");
		return B_DEV_RESOURCE_CONFLICT;
	}

	endpoint->used++;
	descriptor->next = endpoint->td_head;
	endpoint->td_head = descriptor;

	uint32 link = endpoint->next, eventdata = link + 1, next = eventdata + 1;
	if (eventdata == XHCI_ENDPOINT_RING_SIZE || next == XHCI_ENDPOINT_RING_SIZE) {
		// If it's "next" not "eventdata" that got us here, we will be leaving
		// one TRB at the end of the ring unused.
		eventdata = 0;
		next = 1;
	}

	TRACE("link descriptor for pipe: link %d, next %d\n", link, next);

	// Add a Link TRB to the end of the descriptor.
	phys_addr_t addr = endpoint->trb_addr + (eventdata * sizeof(xhci_trb));
	descriptor->trbs[descriptor->trb_used].address = addr;
	descriptor->trbs[descriptor->trb_used].status = TRB_2_IRQ(0);
	descriptor->trbs[descriptor->trb_used].flags = TRB_3_TYPE(TRB_TYPE_LINK)
		| TRB_3_CHAIN_BIT | TRB_3_CYCLE_BIT;
		// It is specified that (XHCI 1.2 § 4.12.3 Note 2 p251) if the TRB
		// following one with the ENT bit set is a Link TRB, the Link TRB
		// shall be evaluated *and* the subsequent TRB shall be. Thus a
		// TRB_3_ENT_BIT is unnecessary here; and from testing seems to
		// break all transfers on a (very) small number of controllers.

#if !B_HOST_IS_LENDIAN
	// Convert endianness.
	for (uint32 i = 0; i <= descriptor->trb_used; i++) {
		descriptor->trbs[i].address =
			B_HOST_TO_LENDIAN_INT64(descriptor->trbs[i].address);
		descriptor->trbs[i].status =
			B_HOST_TO_LENDIAN_INT32(descriptor->trbs[i].status);
		descriptor->trbs[i].flags =
			B_HOST_TO_LENDIAN_INT32(descriptor->trbs[i].flags);
	}
#endif

	// Link the descriptor.
	endpoint->trbs[link].address =
		B_HOST_TO_LENDIAN_INT64(descriptor->trb_addr);
	endpoint->trbs[link].status =
		B_HOST_TO_LENDIAN_INT32(TRB_2_IRQ(0));
	endpoint->trbs[link].flags =
		B_HOST_TO_LENDIAN_INT32(TRB_3_TYPE(TRB_TYPE_LINK));

	// Set up the Event Data TRB (XHCI 1.2 § 4.11.5.2 p230.)
	//
	// We do this on the main ring for two reasons: first, to avoid a small
	// potential race between the interrupt and the controller evaluating
	// the link TRB to get back onto the ring; and second, because many
	// controllers throw errors if the target of a Link TRB is not valid
	// (i.e. does not have its Cycle Bit set.)
	//
	// We also set the "address" field, which the controller will copy
	// verbatim into the TRB it posts to the event ring, to be the last
	// "real" TRB in the TD; this will allow us to determine what transfer
	// the resulting Transfer Event TRB refers to.
	endpoint->trbs[eventdata].address =
		B_HOST_TO_LENDIAN_INT64(descriptor->trb_addr
			+ (descriptor->trb_used - 1) * sizeof(xhci_trb));
	endpoint->trbs[eventdata].status =
		B_HOST_TO_LENDIAN_INT32(TRB_2_IRQ(0));
	endpoint->trbs[eventdata].flags =
		B_HOST_TO_LENDIAN_INT32(TRB_3_TYPE(TRB_TYPE_EVENT_DATA)
			| TRB_3_IOC_BIT | TRB_3_CYCLE_BIT);

	endpoint->trbs[next].address = 0;
	endpoint->trbs[next].status = 0;
	endpoint->trbs[next].flags = 0;

	memory_write_barrier();

	// Everything is ready, so write the cycle bit.
	endpoint->trbs[link].flags |= B_HOST_TO_LENDIAN_INT32(TRB_3_CYCLE_BIT);

	TRACE("_LinkDescriptorForPipe pLink %p phys 0x%" B_PRIxPHYSADDR
		" 0x%" B_PRIxPHYSADDR " 0x%08" B_PRIx32 "\n", &endpoint->trbs[link],
		endpoint->trb_addr + link * sizeof(struct xhci_trb),
		endpoint->trbs[link].address,
		B_LENDIAN_TO_HOST_INT32(endpoint->trbs[link].flags));

	endpoint->next = next;
	endpointLocker.Unlock();

	TRACE("Endpoint status 0x%08" B_PRIx32 " 0x%08" B_PRIx32 " 0x%016" B_PRIx64 "\n",
		_ReadContext(&endpoint->device->device_ctx->endpoints[endpoint->id].dwendpoint0),
		_ReadContext(&endpoint->device->device_ctx->endpoints[endpoint->id].dwendpoint1),
		_ReadContext(&endpoint->device->device_ctx->endpoints[endpoint->id].qwendpoint2));

	Ring(endpoint->device->slot, endpoint->id + 1);

	TRACE("Endpoint status 0x%08" B_PRIx32 " 0x%08" B_PRIx32 " 0x%016" B_PRIx64 "\n",
		_ReadContext(&endpoint->device->device_ctx->endpoints[endpoint->id].dwendpoint0),
		_ReadContext(&endpoint->device->device_ctx->endpoints[endpoint->id].dwendpoint1),
		_ReadContext(&endpoint->device->device_ctx->endpoints[endpoint->id].qwendpoint2));

	return B_OK;
}


status_t
XHCI::_UnlinkDescriptorForPipe(xhci_td *descriptor, xhci_endpoint *endpoint)
{
	TRACE("unlink descriptor for pipe\n");
	// We presume that the caller has already locked or owns the endpoint.

	endpoint->used--;
	if (descriptor == endpoint->td_head) {
		endpoint->td_head = descriptor->next;
		descriptor->next = NULL;
		return B_OK;
	} else {
		for (xhci_td *td = endpoint->td_head; td->next != NULL; td = td->next) {
			if (td->next == descriptor) {
				td->next = descriptor->next;
				descriptor->next = NULL;
				return B_OK;
			}
		}
	}

	endpoint->used++;
	return B_ERROR;
}


status_t
XHCI::ConfigureEndpoint(xhci_endpoint* ep, uint8 slot, uint8 number, uint8 type,
	bool directionIn, uint16 interval, uint16 maxPacketSize, usb_speed speed,
	uint8 maxBurst, uint16 bytesPerInterval)
{
	struct xhci_device* device = &fDevices[slot];

	uint32 dwendpoint0 = 0;
	uint32 dwendpoint1 = 0;
	uint64 qwendpoint2 = 0;
	uint32 dwendpoint4 = 0;

	// Compute and assign the endpoint type. (XHCI 1.2 § 6.2.3 Table 6-9 p452.)
	uint8 xhciType = 4;
	if ((type & USB_OBJECT_INTERRUPT_PIPE) != 0)
		xhciType = 3;
	if ((type & USB_OBJECT_BULK_PIPE) != 0)
		xhciType = 2;
	if ((type & USB_OBJECT_ISO_PIPE) != 0)
		xhciType = 1;
	xhciType |= directionIn ? (1 << 2) : 0;
	dwendpoint1 |= ENDPOINT_1_EPTYPE(xhciType);

	// Compute and assign interval. (XHCI 1.2 § 6.2.3.6 p456.)
	uint16 calcInterval;
	if ((type & USB_OBJECT_BULK_PIPE) != 0
			|| (type & USB_OBJECT_CONTROL_PIPE) != 0) {
		// Bulk and Control endpoints never issue NAKs.
		calcInterval = 0;
	} else {
		switch (speed) {
		case USB_SPEED_FULLSPEED:
			if ((type & USB_OBJECT_ISO_PIPE) != 0) {
				// Convert 1-16 into 3-18.
				calcInterval = min_c(max_c(interval, 1), 16) + 2;
				break;
			}

			// fall through
		case USB_SPEED_LOWSPEED: {
			// Convert 1ms-255ms into 3-10.

			// Find the index of the highest set bit in "interval".
			uint32 temp = min_c(max_c(interval, 1), 255);
			for (calcInterval = 0; temp != 1; calcInterval++)
				temp = temp >> 1;
			calcInterval += 3;
			break;
		}

		case USB_SPEED_HIGHSPEED:
		case USB_SPEED_SUPERSPEED:
		case USB_SPEED_SUPERSPEEDPLUS:
		default:
			// Convert 1-16 into 0-15.
			calcInterval = min_c(max_c(interval, 1), 16) - 1;
			break;
		}
	}
	dwendpoint0 |= ENDPOINT_0_INTERVAL(calcInterval);

	// For non-isochronous endpoints, we want the controller to retry failed
	// transfers, if possible. (XHCI 1.2 § 4.10.2.3 p197.)
	if ((type & USB_OBJECT_ISO_PIPE) == 0)
		dwendpoint1 |= ENDPOINT_1_CERR(3);

	// Assign maximum burst size. For USB3 devices this is passed in; for
	// all other devices we compute it. (XHCI 1.2 § 4.8.2 p161.)
	if (speed == USB_SPEED_HIGHSPEED && (type & (USB_OBJECT_INTERRUPT_PIPE
			| USB_OBJECT_ISO_PIPE)) != 0) {
		maxBurst = (maxPacketSize & 0x1800) >> 11;
	} else if (speed < USB_SPEED_SUPERSPEED) {
		maxBurst = 0;
	}
	dwendpoint1 |= ENDPOINT_1_MAXBURST(maxBurst);

	// Assign maximum packet size, set the ring address, and set the
	// "Dequeue Cycle State" bit. (XHCI 1.2 § 6.2.3 Table 6-10 p453.)
	dwendpoint1 |= ENDPOINT_1_MAXPACKETSIZE(maxPacketSize);
	qwendpoint2 |= ENDPOINT_2_DCS_BIT | ep->trb_addr;

	// The Max Burst Payload is the number of bytes moved by a
	// maximum sized burst. (XHCI 1.2 § 4.11.7.1 p236.)
	ep->max_burst_payload = (maxBurst + 1) * maxPacketSize;
	if (ep->max_burst_payload == 0) {
		TRACE_ERROR("ConfigureEndpoint() failed invalid max_burst_payload\n");
		return B_BAD_VALUE;
	}

	// Assign average TRB length.
	if ((type & USB_OBJECT_CONTROL_PIPE) != 0) {
		// Control pipes are a special case, as they rarely have
		// outbound transfers of any substantial size.
		dwendpoint4 |= ENDPOINT_4_AVGTRBLENGTH(8);
	} else if ((type & USB_OBJECT_ISO_PIPE) != 0) {
		// Isochronous pipes are another special case: the TRB size will be
		// one packet (which is normally smaller than the max packet size,
		// but we don't know what it is here.)
		dwendpoint4 |= ENDPOINT_4_AVGTRBLENGTH(maxPacketSize);
	} else {
		// Under all other circumstances, we put max_burst_payload in a TRB.
		dwendpoint4 |= ENDPOINT_4_AVGTRBLENGTH(ep->max_burst_payload);
	}

	// Assign maximum ESIT payload. (XHCI 1.2 § 4.14.2 p259.)
	if ((type & (USB_OBJECT_INTERRUPT_PIPE | USB_OBJECT_ISO_PIPE)) != 0) {
		// TODO: For SuperSpeedPlus endpoints, there is yet another descriptor
		// for isochronous endpoints that specifies the maximum ESIT payload.
		// We don't fetch this yet, so just fall back to the USB2 computation
		// method if bytesPerInterval is 0.
		if (speed >= USB_SPEED_SUPERSPEED && bytesPerInterval != 0)
			dwendpoint4 |= ENDPOINT_4_MAXESITPAYLOAD(bytesPerInterval);
		else if (speed >= USB_SPEED_HIGHSPEED)
			dwendpoint4 |= ENDPOINT_4_MAXESITPAYLOAD((maxBurst + 1) * maxPacketSize);
	}

	_WriteContext(&device->input_ctx->endpoints[number].dwendpoint0,
		dwendpoint0);
	_WriteContext(&device->input_ctx->endpoints[number].dwendpoint1,
		dwendpoint1);
	_WriteContext(&device->input_ctx->endpoints[number].qwendpoint2,
		qwendpoint2);
	_WriteContext(&device->input_ctx->endpoints[number].dwendpoint4,
		dwendpoint4);

	TRACE("endpoint 0x%" B_PRIx32 " 0x%" B_PRIx32 " 0x%" B_PRIx64 " 0x%"
		B_PRIx32 "\n",
		_ReadContext(&device->input_ctx->endpoints[number].dwendpoint0),
		_ReadContext(&device->input_ctx->endpoints[number].dwendpoint1),
		_ReadContext(&device->input_ctx->endpoints[number].qwendpoint2),
		_ReadContext(&device->input_ctx->endpoints[number].dwendpoint4));

	return B_OK;
}


status_t
XHCI::GetPortSpeed(uint8 index, usb_speed* speed)
{
	if (index >= fPortCount)
		return B_BAD_INDEX;

	uint32 portStatus = ReadOpReg(XHCI_PORTSC(index));

	switch (PS_SPEED_GET(portStatus)) {
	case 2:
		*speed = USB_SPEED_LOWSPEED;
		break;
	case 1:
		*speed = USB_SPEED_FULLSPEED;
		break;
	case 3:
		*speed = USB_SPEED_HIGHSPEED;
		break;
	case 4:
		*speed = USB_SPEED_SUPERSPEED;
		break;
	case 5:
		*speed = USB_SPEED_SUPERSPEEDPLUS;
		break;
	default:
		TRACE_ALWAYS("nonstandard port speed %" B_PRId32 ", assuming SuperSpeed\n",
			PS_SPEED_GET(portStatus));
		*speed = USB_SPEED_SUPERSPEED;
		break;
	}

	return B_OK;
}


status_t
XHCI::GetPortStatus(uint8 index, usb_port_status* status)
{
	if (index >= fPortCount)
		return B_BAD_INDEX;

	status->status = status->change = 0;
	uint32 portStatus = ReadOpReg(XHCI_PORTSC(index));
	TRACE("port %" B_PRId8 " status=0x%08" B_PRIx32 "\n", index, portStatus);

	// build the status
	switch (PS_SPEED_GET(portStatus)) {
	case 3:
		status->status |= PORT_STATUS_HIGH_SPEED;
		break;
	case 2:
		status->status |= PORT_STATUS_LOW_SPEED;
		break;
	default:
		break;
	}

	if (portStatus & PS_CCS)
		status->status |= PORT_STATUS_CONNECTION;
	if (portStatus & PS_PED)
		status->status |= PORT_STATUS_ENABLE;
	if (portStatus & PS_OCA)
		status->status |= PORT_STATUS_OVER_CURRENT;
	if (portStatus & PS_PR)
		status->status |= PORT_STATUS_RESET;
	if (portStatus & PS_PP) {
		if (fPortSpeeds[index] >= USB_SPEED_SUPERSPEED)
			status->status |= PORT_STATUS_SS_POWER;
		else
			status->status |= PORT_STATUS_POWER;
	}
	if (fPortSpeeds[index] >= USB_SPEED_SUPERSPEED)
		status->status |= portStatus & PS_PLS_MASK;

	// build the change
	if (portStatus & PS_CSC)
		status->change |= PORT_STATUS_CONNECTION;
	if (portStatus & PS_PEC)
		status->change |= PORT_STATUS_ENABLE;
	if (portStatus & PS_OCC)
		status->change |= PORT_STATUS_OVER_CURRENT;
	if (portStatus & PS_PRC)
		status->change |= PORT_STATUS_RESET;

	if (fPortSpeeds[index] >= USB_SPEED_SUPERSPEED) {
		if (portStatus & PS_PLC)
			status->change |= PORT_CHANGE_LINK_STATE;
		if (portStatus & PS_WRC)
			status->change |= PORT_CHANGE_BH_PORT_RESET;
	}

	return B_OK;
}


status_t
XHCI::SetPortFeature(uint8 index, uint16 feature)
{
	TRACE("set port feature index %u feature %u\n", index, feature);
	if (index >= fPortCount)
		return B_BAD_INDEX;

	uint32 portRegister = XHCI_PORTSC(index);
	uint32 portStatus = ReadOpReg(portRegister) & ~PS_CLEAR;

	switch (feature) {
	case PORT_SUSPEND:
		if ((portStatus & PS_PED) == 0 || (portStatus & PS_PR)
			|| (portStatus & PS_PLS_MASK) >= PS_XDEV_U3) {
			TRACE_ERROR("USB core suspending device not in U0/U1/U2.\n");
			return B_BAD_VALUE;
		}
		portStatus &= ~PS_PLS_MASK;
		WriteOpReg(portRegister, portStatus | PS_LWS | PS_XDEV_U3);
		break;

	case PORT_RESET:
		WriteOpReg(portRegister, portStatus | PS_PR);
		break;

	case PORT_POWER:
		WriteOpReg(portRegister, portStatus | PS_PP);
		break;
	default:
		return B_BAD_VALUE;
	}
	ReadOpReg(portRegister);
	return B_OK;
}


status_t
XHCI::ClearPortFeature(uint8 index, uint16 feature)
{
	TRACE("clear port feature index %u feature %u\n", index, feature);
	if (index >= fPortCount)
		return B_BAD_INDEX;

	uint32 portRegister = XHCI_PORTSC(index);
	uint32 portStatus = ReadOpReg(portRegister) & ~PS_CLEAR;

	switch (feature) {
	case PORT_SUSPEND:
		portStatus = ReadOpReg(portRegister);
		if (portStatus & PS_PR)
			return B_BAD_VALUE;
		if (portStatus & PS_XDEV_U3) {
			if ((portStatus & PS_PED) == 0)
				return B_BAD_VALUE;
			portStatus &= ~PS_PLS_MASK;
			WriteOpReg(portRegister, portStatus | PS_XDEV_U0 | PS_LWS);
		}
		break;
	case PORT_ENABLE:
		WriteOpReg(portRegister, portStatus | PS_PED);
		break;
	case PORT_POWER:
		WriteOpReg(portRegister, portStatus & ~PS_PP);
		break;
	case C_PORT_CONNECTION:
		WriteOpReg(portRegister, portStatus | PS_CSC);
		break;
	case C_PORT_ENABLE:
		WriteOpReg(portRegister, portStatus | PS_PEC);
		break;
	case C_PORT_OVER_CURRENT:
		WriteOpReg(portRegister, portStatus | PS_OCC);
		break;
	case C_PORT_RESET:
		WriteOpReg(portRegister, portStatus | PS_PRC);
		break;
	case C_PORT_BH_PORT_RESET:
		WriteOpReg(portRegister, portStatus | PS_WRC);
		break;
	case C_PORT_LINK_STATE:
		WriteOpReg(portRegister, portStatus | PS_PLC);
		break;
	default:
		return B_BAD_VALUE;
	}

	ReadOpReg(portRegister);
	return B_OK;
}


status_t
XHCI::ControllerHalt()
{
	// Mask off run state
	WriteOpReg(XHCI_CMD, ReadOpReg(XHCI_CMD) & ~CMD_RUN);

	// wait for shutdown state
	if (WaitOpBits(XHCI_STS, STS_HCH, STS_HCH) != B_OK) {
		TRACE_ERROR("HCH shutdown timeout\n");
		return B_ERROR;
	}
	return B_OK;
}


status_t
XHCI::ControllerReset()
{
	TRACE("ControllerReset() cmd: 0x%" B_PRIx32 " sts: 0x%" B_PRIx32 "\n",
		ReadOpReg(XHCI_CMD), ReadOpReg(XHCI_STS));
	WriteOpReg(XHCI_CMD, ReadOpReg(XHCI_CMD) | CMD_HCRST);

	if (WaitOpBits(XHCI_CMD, CMD_HCRST, 0) != B_OK) {
		TRACE_ERROR("ControllerReset() failed CMD_HCRST\n");
		return B_ERROR;
	}

	if (WaitOpBits(XHCI_STS, STS_CNR, 0) != B_OK) {
		TRACE_ERROR("ControllerReset() failed STS_CNR\n");
		return B_ERROR;
	}

	return B_OK;
}


int32
XHCI::InterruptHandler(void* data)
{
	return ((XHCI*)data)->Interrupt();
}


int32
XHCI::Interrupt()
{
	SpinLocker _(&fSpinlock);

	uint32 status = ReadOpReg(XHCI_STS);
	uint32 temp = ReadRunReg32(XHCI_IMAN(0));
	WriteOpReg(XHCI_STS, status);
	WriteRunReg32(XHCI_IMAN(0), temp);

	int32 result = B_HANDLED_INTERRUPT;

	if ((status & STS_HCH) != 0) {
		TRACE_ERROR("Host Controller halted\n");
		return result;
	}
	if ((status & STS_HSE) != 0) {
		TRACE_ERROR("Host System Error\n");
		return result;
	}
	if ((status & STS_HCE) != 0) {
		TRACE_ERROR("Host Controller Error\n");
		return result;
	}

	if ((status & STS_EINT) == 0) {
		TRACE("STS: 0x%" B_PRIx32 " IRQ_PENDING: 0x%" B_PRIx32 "\n",
			status, temp);
		return B_UNHANDLED_INTERRUPT;
	}

	TRACE("Event Interrupt\n");
	release_sem_etc(fEventSem, 1, B_DO_NOT_RESCHEDULE);
	return B_INVOKE_SCHEDULER;
}


void
XHCI::Ring(uint8 slot, uint8 endpoint)
{
	TRACE("Ding Dong! slot:%d endpoint %d\n", slot, endpoint)
	if ((slot == 0 && endpoint > 0) || (slot > 0 && endpoint == 0))
		panic("Ring() invalid slot/endpoint combination\n");
	if (slot > fSlotCount || endpoint >= XHCI_MAX_ENDPOINTS)
		panic("Ring() invalid slot or endpoint\n");

	WriteDoorReg32(XHCI_DOORBELL(slot), XHCI_DOORBELL_TARGET(endpoint)
		| XHCI_DOORBELL_STREAMID(0));
	ReadDoorReg32(XHCI_DOORBELL(slot));
		// Flush PCI writes
}


void
XHCI::QueueCommand(xhci_trb* trb)
{
	uint8 i, j;
	uint32 temp;

	i = fCmdIdx;
	j = fCmdCcs;

	TRACE("command[%u] = %" B_PRId32 " (0x%016" B_PRIx64 ", 0x%08" B_PRIx32
		", 0x%08" B_PRIx32 ")\n", i, TRB_3_TYPE_GET(trb->flags), trb->address,
		trb->status, trb->flags);

	fCmdRing[i].address = trb->address;
	fCmdRing[i].status = trb->status;
	temp = trb->flags;

	if (j)
		temp |= TRB_3_CYCLE_BIT;
	else
		temp &= ~TRB_3_CYCLE_BIT;
	temp &= ~TRB_3_TC_BIT;
	fCmdRing[i].flags = B_HOST_TO_LENDIAN_INT32(temp);

	fCmdAddr = fErst->rs_addr + (XHCI_MAX_EVENTS + i) * sizeof(xhci_trb);

	i++;

	if (i == (XHCI_MAX_COMMANDS - 1)) {
		temp = TRB_3_TYPE(TRB_TYPE_LINK) | TRB_3_TC_BIT;
		if (j)
			temp |= TRB_3_CYCLE_BIT;
		fCmdRing[i].flags = B_HOST_TO_LENDIAN_INT32(temp);

		i = 0;
		j ^= 1;
	}

	fCmdIdx = i;
	fCmdCcs = j;
}


void
XHCI::HandleCmdComplete(xhci_trb* trb)
{
	if (fCmdAddr == trb->address) {
		TRACE("Received command event\n");
		fCmdResult[0] = trb->status;
		fCmdResult[1] = B_LENDIAN_TO_HOST_INT32(trb->flags);
		release_sem_etc(fCmdCompSem, 1, B_DO_NOT_RESCHEDULE);
	} else
		TRACE_ERROR("received command event for unknown command!\n")
}


void
XHCI::HandleTransferComplete(xhci_trb* trb)
{
	const uint32 flags = B_LENDIAN_TO_HOST_INT32(trb->flags);
	const uint8 endpointNumber = TRB_3_ENDPOINT_GET(flags),
		slot = TRB_3_SLOT_GET(flags);

	if (slot > fSlotCount)
		TRACE_ERROR("invalid slot\n");
	if (endpointNumber == 0 || endpointNumber >= XHCI_MAX_ENDPOINTS) {
		TRACE_ERROR("invalid endpoint\n");
		return;
	}

	xhci_device *device = &fDevices[slot];
	xhci_endpoint *endpoint = &device->endpoints[endpointNumber - 1];

	if (endpoint->trbs == NULL) {
		TRACE_ERROR("got TRB but endpoint is not allocated!\n");
		return;
	}

	// Use mutex_trylock first, in case we are in KDL.
	MutexLocker endpointLocker(endpoint->lock, mutex_trylock(&endpoint->lock) == B_OK);
	if (!endpointLocker.IsLocked()) {
		// We failed to get the lock. Most likely it was destroyed
		// while we were waiting for it.
		return;
	}

	TRACE("HandleTransferComplete: ed %" B_PRIu32 ", status %" B_PRId32 "\n",
		  (flags & TRB_3_EVENT_DATA_BIT), trb->status);

	uint8 completionCode = TRB_2_COMP_CODE_GET(trb->status);

	if (completionCode == COMP_RING_OVERRUN || completionCode == COMP_RING_UNDERRUN) {
		// These occur on isochronous endpoints when there is no TRB ready to be
		// executed at the appropriate time. (XHCI 1.2 § 4.10.3.1 p204.)
		endpoint->status = completionCode;
		return;
	}

	int32 remainder = TRB_2_REM_GET(trb->status), transferred = -1;
	if ((flags & TRB_3_EVENT_DATA_BIT) != 0) {
		// In the case of an Event Data TRB, value in the status field refers
		// to the actual number of bytes transferred across the whole TD.
		// (XHCI 1.2 § 6.4.2.1 Table 6-38 p478.)
		transferred = remainder;
		remainder = -1;
	} else {
		// This should only occur under error conditions, or for isochronous transfers.
		TRACE("got transfer event for a non-Event Data TRB!\n");

		if (completionCode == COMP_STOPPED_LENGTH_INVALID)
			remainder = -1;
	}

	if (completionCode != COMP_SUCCESS && completionCode != COMP_SHORT_PACKET
			&& completionCode != COMP_STOPPED && completionCode != COMP_STOPPED_LENGTH_INVALID) {
		TRACE_ALWAYS("transfer error on slot %" B_PRId8 " endpoint %" B_PRId8
			": %s\n", slot, endpointNumber, xhci_error_string(completionCode));
	}

	phys_addr_t source = B_LENDIAN_TO_HOST_INT64(trb->address);
	if (source >= endpoint->trb_addr
			&& (source - endpoint->trb_addr) < (XHCI_ENDPOINT_RING_SIZE * sizeof(xhci_trb))) {
		// The "source" address points to a TRB on the ring.
		// See if we can figure out what it really corresponds to.
		const int64 offset = (source - endpoint->trb_addr) / sizeof(xhci_trb);
		const int32 type = TRB_3_TYPE_GET(endpoint->trbs[offset].flags);
		if (type == TRB_TYPE_EVENT_DATA || type == TRB_TYPE_LINK)
			source = B_LENDIAN_TO_HOST_INT64(endpoint->trbs[offset].address);
	}

	for (xhci_td *td = endpoint->td_head; td != NULL; td = td->next) {
		int64 offset = (source - td->trb_addr) / sizeof(xhci_trb);
		if (offset < 0 || offset >= td->trb_count)
			continue;

		TRACE("HandleTransferComplete td %p trb %" B_PRId64 " found\n",
			td, offset);

		if (td->transfer != NULL && td->transfer->IsochronousData() != NULL) {
			usb_isochronous_data* isochronousData = td->transfer->IsochronousData();
			usb_iso_packet_descriptor& descriptor = isochronousData->packet_descriptors[offset];
			if (transferred < 0)
				transferred = (TRB_2_BYTES_GET(td->trbs[offset].status) - remainder);
			descriptor.actual_length = transferred;
			descriptor.status = xhci_error_status(completionCode,
				(td->transfer->TransferPipe()->Direction() != Pipe::Out));

			// Don't double-report completion status.
			completionCode = COMP_SUCCESS;

			if (offset != (td->trb_used - 1)) {
				// We'll be sent here again.
				return;
			}

			// Compute the real transferred length.
			transferred = 0;
			for (int32 i = 0; i < offset; i++) {
				usb_iso_packet_descriptor& descriptor = isochronousData->packet_descriptors[i];
				if (descriptor.status == B_NO_INIT) {
					// Assume success.
					descriptor.actual_length = descriptor.request_length;
					descriptor.status = B_OK;
				}
				transferred += descriptor.actual_length;
			}

			// Report the endpoint status (if any.)
			if (endpoint->status != 0) {
				completionCode = endpoint->status;
				endpoint->status = 0;
			}
		} else if (completionCode == COMP_STOPPED_LENGTH_INVALID) {
			// To determine transferred length, sum up the lengths of all TRBs
			// prior to the referenced one. (XHCI 1.2 § 4.6.9 p136.)
			transferred = 0;
			for (int32 i = 0; i < offset; i++)
				transferred += TRB_2_BYTES_GET(td->trbs[i].status);
		}

		// The TRB at offset trb_used will be the link TRB, which we do not
		// care about (and should not generate an interrupt at all.) We really
		// care about the properly last TRB, at index "count - 1", which the
		// Event Data TRB that _LinkDescriptorForPipe creates points to.
		//
		// But if we have an unsuccessful completion code, the transfer
		// likely failed midway; so just accept it anyway.
		if (offset == (td->trb_used - 1) || completionCode != COMP_SUCCESS) {
			_UnlinkDescriptorForPipe(td, endpoint);
			endpointLocker.Unlock();

			td->trb_completion_code = completionCode;
			td->td_transferred = transferred;
			td->trb_left = remainder;

			// add descriptor to finished list
			if (mutex_trylock(&fFinishedLock) != B_OK)
				mutex_lock(&fFinishedLock);
			td->next = fFinishedHead;
			fFinishedHead = td;
			mutex_unlock(&fFinishedLock);

			release_sem_etc(fFinishTransfersSem, 1, B_DO_NOT_RESCHEDULE);
			TRACE("HandleTransferComplete td %p done\n", td);
		} else {
			TRACE_ERROR("successful TRB 0x%" B_PRIxPHYSADDR " was found, but it wasn't "
				"the last in the TD!\n", source);
		}
		return;
	}
	TRACE_ERROR("TRB 0x%" B_PRIxPHYSADDR " was not found in the endpoint!\n", source);
}


void
XHCI::DumpRing(xhci_trb *trbs, uint32 size)
{
	if (!Lock()) {
		TRACE("Unable to get lock!\n");
		return;
	}

	for (uint32 i = 0; i < size; i++) {
		TRACE("command[%" B_PRId32 "] = %" B_PRId32 " (0x%016" B_PRIx64 ","
			" 0x%08" B_PRIx32 ", 0x%08" B_PRIx32 ")\n", i,
			TRB_3_TYPE_GET(B_LENDIAN_TO_HOST_INT32(trbs[i].flags)),
			trbs[i].address, trbs[i].status, trbs[i].flags);
	}

	Unlock();
}


status_t
XHCI::DoCommand(xhci_trb* trb)
{
	if (!Lock()) {
		TRACE("Unable to get lock!\n");
		return B_ERROR;
	}

	QueueCommand(trb);
	Ring(0, 0);

	// Begin with a 50ms timeout.
	if (acquire_sem_etc(fCmdCompSem, 1, B_RELATIVE_TIMEOUT, 50 * 1000) != B_OK) {
		// We've hit the timeout. In some error cases, interrupts are not
		// generated; so here we force the event ring to be polled once.
		release_sem(fEventSem);

		// Now try again, this time with a 750ms timeout.
		if (acquire_sem_etc(fCmdCompSem, 1, B_RELATIVE_TIMEOUT,
				750 * 1000) != B_OK) {
			TRACE("Unable to obtain fCmdCompSem!\n");
			fCmdAddr = 0;
			Unlock();
			return B_TIMED_OUT;
		}
	}

	// eat up sems that have been released by multiple interrupts
	int32 semCount = 0;
	get_sem_count(fCmdCompSem, &semCount);
	if (semCount > 0)
		acquire_sem_etc(fCmdCompSem, semCount, B_RELATIVE_TIMEOUT, 0);

	status_t status = B_OK;
	uint32 completionCode = TRB_2_COMP_CODE_GET(fCmdResult[0]);
	TRACE("command complete\n");
	if (completionCode != COMP_SUCCESS) {
		TRACE_ERROR("unsuccessful command %" B_PRId32 ", error %s (%" B_PRId32 ")\n",
			TRB_3_TYPE_GET(trb->flags), xhci_error_string(completionCode),
			completionCode);
		status = B_IO_ERROR;
	}

	trb->status = fCmdResult[0];
	trb->flags = fCmdResult[1];

	fCmdAddr = 0;
	Unlock();
	return status;
}


status_t
XHCI::Noop()
{
	TRACE("Issue No-Op\n");
	xhci_trb trb;
	trb.address = 0;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_CMD_NOOP);

	return DoCommand(&trb);
}


status_t
XHCI::EnableSlot(uint8* slot)
{
	TRACE("Enable Slot\n");
	xhci_trb trb;
	trb.address = 0;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_ENABLE_SLOT);

	status_t status = DoCommand(&trb);
	if (status != B_OK)
		return status;

	*slot = TRB_3_SLOT_GET(trb.flags);
	return *slot != 0 ? B_OK : B_BAD_VALUE;
}


status_t
XHCI::DisableSlot(uint8 slot)
{
	TRACE("Disable Slot\n");
	xhci_trb trb;
	trb.address = 0;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_DISABLE_SLOT) | TRB_3_SLOT(slot);

	return DoCommand(&trb);
}


status_t
XHCI::SetAddress(uint64 inputContext, bool bsr, uint8 slot)
{
	TRACE("Set Address\n");
	xhci_trb trb;
	trb.address = inputContext;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_ADDRESS_DEVICE) | TRB_3_SLOT(slot);

	if (bsr)
		trb.flags |= TRB_3_BSR_BIT;

	return DoCommand(&trb);
}


status_t
XHCI::ConfigureEndpoint(uint64 inputContext, bool deconfigure, uint8 slot)
{
	TRACE("Configure Endpoint\n");
	xhci_trb trb;
	trb.address = inputContext;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_CONFIGURE_ENDPOINT) | TRB_3_SLOT(slot);

	if (deconfigure)
		trb.flags |= TRB_3_DCEP_BIT;

	return DoCommand(&trb);
}


status_t
XHCI::EvaluateContext(uint64 inputContext, uint8 slot)
{
	TRACE("Evaluate Context\n");
	xhci_trb trb;
	trb.address = inputContext;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_EVALUATE_CONTEXT) | TRB_3_SLOT(slot);

	return DoCommand(&trb);
}


status_t
XHCI::ResetEndpoint(bool preserve, xhci_endpoint* endpoint)
{
	TRACE("Reset Endpoint\n");

	switch (_GetEndpointState(endpoint)) {
		case ENDPOINT_STATE_STOPPED:
			TRACE("Reset Endpoint: already stopped");
			return B_OK;
		case ENDPOINT_STATE_HALTED:
			TRACE("Reset Endpoint: warning, weird state!");
		default:
			break;
	}

	xhci_trb trb;
	trb.address = 0;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_RESET_ENDPOINT)
		| TRB_3_SLOT(endpoint->device->slot) | TRB_3_ENDPOINT(endpoint->id + 1);
	if (preserve)
		trb.flags |= TRB_3_PRSV_BIT;

	return DoCommand(&trb);
}


status_t
XHCI::StopEndpoint(bool suspend, xhci_endpoint* endpoint)
{
	TRACE("Stop Endpoint\n");

	switch (_GetEndpointState(endpoint)) {
		case ENDPOINT_STATE_HALTED:
			TRACE("Stop Endpoint: error, halted");
			return B_DEV_STALLED;
		case ENDPOINT_STATE_STOPPED:
			TRACE("Stop Endpoint: already stopped");
			return B_OK;
		default:
			break;
	}

	xhci_trb trb;
	trb.address = 0;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_STOP_ENDPOINT)
		| TRB_3_SLOT(endpoint->device->slot) | TRB_3_ENDPOINT(endpoint->id + 1);
	if (suspend)
		trb.flags |= TRB_3_SUSPEND_ENDPOINT_BIT;

	return DoCommand(&trb);
}


status_t
XHCI::SetTRDequeue(uint64 dequeue, uint16 stream, uint8 endpoint, uint8 slot)
{
	TRACE("Set TR Dequeue\n");
	xhci_trb trb;
	trb.address = dequeue | ENDPOINT_2_DCS_BIT;
		// The DCS bit is copied from the address field as in ConfigureEndpoint.
		// (XHCI 1.2 § 4.6.10 p142.)
	trb.status = TRB_2_STREAM(stream);
	trb.flags = TRB_3_TYPE(TRB_TYPE_SET_TR_DEQUEUE)
		| TRB_3_SLOT(slot) | TRB_3_ENDPOINT(endpoint);

	return DoCommand(&trb);
}


status_t
XHCI::ResetDevice(uint8 slot)
{
	TRACE("Reset Device\n");
	xhci_trb trb;
	trb.address = 0;
	trb.status = 0;
	trb.flags = TRB_3_TYPE(TRB_TYPE_RESET_DEVICE) | TRB_3_SLOT(slot);

	return DoCommand(&trb);
}


int32
XHCI::EventThread(void* data)
{
	((XHCI *)data)->CompleteEvents();
	return B_OK;
}


void
XHCI::CompleteEvents()
{
	while (!fStopThreads) {
		if (acquire_sem(fEventSem) < B_OK)
			continue;

		// eat up sems that have been released by multiple interrupts
		int32 semCount = 0;
		get_sem_count(fEventSem, &semCount);
		if (semCount > 0)
			acquire_sem_etc(fEventSem, semCount, B_RELATIVE_TIMEOUT, 0);

		ProcessEvents();
	}
}


void
XHCI::ProcessEvents()
{
	// Use mutex_trylock first, in case we are in KDL.
	MutexLocker locker(fEventLock, mutex_trylock(&fEventLock) == B_OK);
	if (!locker.IsLocked()) {
		// We failed to get the lock. This really should not happen.
		TRACE_ERROR("failed to acquire event lock!\n");
		return;
	}

	uint16 i = fEventIdx;
	uint8 j = fEventCcs;
	uint8 t = 2;

	while (1) {
		uint32 temp = B_LENDIAN_TO_HOST_INT32(fEventRing[i].flags);
		uint8 event = TRB_3_TYPE_GET(temp);
		TRACE("event[%u] = %u (0x%016" B_PRIx64 " 0x%08" B_PRIx32 " 0x%08"
			B_PRIx32 ")\n", i, event, fEventRing[i].address,
			fEventRing[i].status, B_LENDIAN_TO_HOST_INT32(fEventRing[i].flags));
		uint8 k = (temp & TRB_3_CYCLE_BIT) ? 1 : 0;
		if (j != k)
			break;

		switch (event) {
		case TRB_TYPE_COMMAND_COMPLETION:
			HandleCmdComplete(&fEventRing[i]);
			break;
		case TRB_TYPE_TRANSFER:
			HandleTransferComplete(&fEventRing[i]);
			break;
		case TRB_TYPE_PORT_STATUS_CHANGE:
			TRACE("port change detected\n");
			break;
		default:
			TRACE_ERROR("Unhandled event = %u\n", event);
			break;
		}

		i++;
		if (i == XHCI_MAX_EVENTS) {
			i = 0;
			j ^= 1;
			if (!--t)
				break;
		}
	}

	fEventIdx = i;
	fEventCcs = j;

	uint64 addr = fErst->rs_addr + i * sizeof(xhci_trb);
	WriteRunReg32(XHCI_ERDP_LO(0), (uint32)addr | ERDP_BUSY);
	WriteRunReg32(XHCI_ERDP_HI(0), (uint32)(addr >> 32));
}


int32
XHCI::FinishThread(void* data)
{
	((XHCI *)data)->FinishTransfers();
	return B_OK;
}


void
XHCI::FinishTransfers()
{
	while (!fStopThreads) {
		if (acquire_sem(fFinishTransfersSem) < B_OK)
			continue;

		// eat up sems that have been released by multiple interrupts
		int32 semCount = 0;
		get_sem_count(fFinishTransfersSem, &semCount);
		if (semCount > 0)
			acquire_sem_etc(fFinishTransfersSem, semCount, B_RELATIVE_TIMEOUT, 0);

		mutex_lock(&fFinishedLock);
		TRACE("finishing transfers\n");
		while (fFinishedHead != NULL) {
			xhci_td* td = fFinishedHead;
			fFinishedHead = td->next;
			td->next = NULL;
			mutex_unlock(&fFinishedLock);

			TRACE("finishing transfer td %p\n", td);

			Transfer* transfer = td->transfer;
			if (transfer == NULL) {
				// No transfer? Quick way out.
				FreeDescriptor(td);
				mutex_lock(&fFinishedLock);
				continue;
			}

			bool directionIn = (transfer->TransferPipe()->Direction() != Pipe::Out);

			const uint8 completionCode = td->trb_completion_code;
			status_t callbackStatus = xhci_error_status(completionCode, directionIn);

			size_t actualLength = transfer->FragmentLength();
			if (completionCode != COMP_SUCCESS) {
				actualLength = td->td_transferred;
				if (td->td_transferred == -1)
					actualLength = transfer->FragmentLength() - td->trb_left;
				TRACE("transfer not successful, actualLength=%" B_PRIuSIZE "\n",
					actualLength);
			}

			if (directionIn && actualLength > 0 && !transfer->IsPhysical()) {
				TRACE("copying in iov count %ld\n", transfer->VectorCount());
				status_t status = transfer->PrepareKernelAccess();
				if (status == B_OK) {
					ReadDescriptor(td, transfer->Vector(),
						transfer->VectorCount(), transfer->IsPhysical());
				} else {
					callbackStatus = status;
				}
			}

			FreeDescriptor(td);

			// this transfer may still have data left
			bool finished = true;
			transfer->AdvanceByFragment(actualLength);
			if (completionCode == COMP_SUCCESS
					&& transfer->FragmentLength() > 0) {
				TRACE("still %" B_PRIuSIZE " bytes left on transfer\n",
					transfer->FragmentLength());
				callbackStatus = SubmitTransfer(transfer);
				finished = (callbackStatus != B_OK);
			}
			if (finished) {
				// The actualLength was already handled in AdvanceByFragment.
				transfer->Finished(callbackStatus, 0);
				delete transfer;
			}

			mutex_lock(&fFinishedLock);
		}
		mutex_unlock(&fFinishedLock);
	}
}


inline void
XHCI::WriteOpReg(uint32 reg, uint32 value)
{
	*(volatile uint32 *)(fRegisters + fOperationalRegisterOffset + reg) = value;
}


inline uint32
XHCI::ReadOpReg(uint32 reg)
{
	return *(volatile uint32 *)(fRegisters + fOperationalRegisterOffset + reg);
}


inline status_t
XHCI::WaitOpBits(uint32 reg, uint32 mask, uint32 expected)
{
	int loops = 0;
	uint32 value = ReadOpReg(reg);
	while ((value & mask) != expected) {
		snooze(1000);
		value = ReadOpReg(reg);
		if (loops == 100) {
			TRACE("delay waiting on reg 0x%" B_PRIX32 " match 0x%" B_PRIX32
				" (0x%" B_PRIX32 ")\n",	reg, expected, mask);
		} else if (loops > 250) {
			TRACE_ERROR("timeout waiting on reg 0x%" B_PRIX32
				" match 0x%" B_PRIX32 " (0x%" B_PRIX32 ")\n", reg, expected,
				mask);
			return B_ERROR;
		}
		loops++;
	}
	return B_OK;
}


inline uint32
XHCI::ReadCapReg32(uint32 reg)
{
	return *(volatile uint32 *)(fRegisters + fCapabilityRegisterOffset + reg);
}


inline void
XHCI::WriteCapReg32(uint32 reg, uint32 value)
{
	*(volatile uint32 *)(fRegisters + fCapabilityRegisterOffset + reg) = value;
}


inline uint32
XHCI::ReadRunReg32(uint32 reg)
{
	return *(volatile uint32 *)(fRegisters + fRuntimeRegisterOffset + reg);
}


inline void
XHCI::WriteRunReg32(uint32 reg, uint32 value)
{
	*(volatile uint32 *)(fRegisters + fRuntimeRegisterOffset + reg) = value;
}


inline uint32
XHCI::ReadDoorReg32(uint32 reg)
{
	return *(volatile uint32 *)(fRegisters + fDoorbellRegisterOffset + reg);
}


inline void
XHCI::WriteDoorReg32(uint32 reg, uint32 value)
{
	*(volatile uint32 *)(fRegisters + fDoorbellRegisterOffset + reg) = value;
}


inline addr_t
XHCI::_OffsetContextAddr(addr_t p)
{
	if (fContextSizeShift == 1) {
		// each structure is page aligned, each pointer is 32 bits aligned
		uint32 offset = p & ((B_PAGE_SIZE - 1) & ~31U);
		p += offset;
	}
	return p;
}

inline uint32
XHCI::_ReadContext(uint32* p)
{
	p = (uint32*)_OffsetContextAddr((addr_t)p);
	return *p;
}


inline void
XHCI::_WriteContext(uint32* p, uint32 value)
{
	p = (uint32*)_OffsetContextAddr((addr_t)p);
	*p = value;
}


inline uint64
XHCI::_ReadContext(uint64* p)
{
	p = (uint64*)_OffsetContextAddr((addr_t)p);
	return *p;
}


inline void
XHCI::_WriteContext(uint64* p, uint64 value)
{
	p = (uint64*)_OffsetContextAddr((addr_t)p);
	*p = value;
}