USB: xHCI: Add stack support for xHCI

This adds stack layer for eXtensible Host Controller Interface
which facilitates use of USB 3.0 in host mode.

Adapting xHCI host controller driver in linux-kernel
by Sarah Sharp to needs in u-boot.

Initial porting from Linux kernel version 3.4, with following
top commit history of drivers/usb/host/xhci* :
cf84055 xHCI: Cleanup isoc transfer ring when TD length mismatch found

This adds the basic xHCI host controller driver with bare minimum
features:
- Control/Bulk transfer support has been added with required
  infrastructure for necessary xHC data structures.
- Stream protocol hasn't been supported yet.
- No support for quirky devices has been added.

Signed-off-by: Vikas C Sajjan <vikas.sajjan@samsung.com>
Signed-off-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Marek Vasut <marex@denx.de>
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
new file mode 100644
index 0000000..ceb1573
--- /dev/null
+++ b/drivers/usb/host/xhci.h
@@ -0,0 +1,1255 @@
+/*
+ * USB HOST XHCI Controller
+ *
+ * Based on xHCI host controller driver in linux-kernel
+ * by Sarah Sharp.
+ *
+ * Copyright (C) 2008 Intel Corp.
+ * Author: Sarah Sharp
+ *
+ * Copyright (C) 2013 Samsung Electronics Co.Ltd
+ * Authors: Vivek Gautam <gautam.vivek@samsung.com>
+ *	    Vikas Sajjan <vikas.sajjan@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef HOST_XHCI_H_
+#define HOST_XHCI_H_
+
+#include <asm/cache.h>
+#include <asm/io.h>
+#include <linux/list.h>
+
+#define upper_32_bits(n) (u32)((n) >> 32)
+#define lower_32_bits(n) (u32)(n)
+
+#define MAX_EP_CTX_NUM		31
+#define XHCI_ALIGNMENT		64
+/* Generic timeout for XHCI events */
+#define XHCI_TIMEOUT		5000
+/* Max number of USB devices for any host controller - limit in section 6.1 */
+#define MAX_HC_SLOTS            256
+/* Section 5.3.3 - MaxPorts */
+#define MAX_HC_PORTS            127
+
+/* Up to 16 ms to halt an HC */
+#define XHCI_MAX_HALT_USEC	(16*1000)
+
+#define XHCI_MAX_RESET_USEC	(250*1000)
+
+/*
+ * These bits are Read Only (RO) and should be saved and written to the
+ * registers: 0, 3, 10:13, 30
+ * connect status, over-current status, port speed, and device removable.
+ * connect status and port speed are also sticky - meaning they're in
+ * the AUX well and they aren't changed by a hot, warm, or cold reset.
+ */
+#define XHCI_PORT_RO ((1 << 0) | (1 << 3) | (0xf << 10) | (1 << 30))
+/*
+ * These bits are RW; writing a 0 clears the bit, writing a 1 sets the bit:
+ * bits 5:8, 9, 14:15, 25:27
+ * link state, port power, port indicator state, "wake on" enable state
+ */
+#define XHCI_PORT_RWS ((0xf << 5) | (1 << 9) | (0x3 << 14) | (0x7 << 25))
+/*
+ * These bits are RW; writing a 1 sets the bit, writing a 0 has no effect:
+ * bit 4 (port reset)
+ */
+#define XHCI_PORT_RW1S ((1 << 4))
+/*
+ * These bits are RW; writing a 1 clears the bit, writing a 0 has no effect:
+ * bits 1, 17, 18, 19, 20, 21, 22, 23
+ * port enable/disable, and
+ * change bits: connect, PED,
+ * warm port reset changed (reserved zero for USB 2.0 ports),
+ * over-current, reset, link state, and L1 change
+ */
+#define XHCI_PORT_RW1CS ((1 << 1) | (0x7f << 17))
+/*
+ * Bit 16 is RW, and writing a '1' to it causes the link state control to be
+ * latched in
+ */
+#define XHCI_PORT_RW ((1 << 16))
+/*
+ * These bits are Reserved Zero (RsvdZ) and zero should be written to them:
+ * bits 2, 24, 28:31
+ */
+#define XHCI_PORT_RZ ((1 << 2) | (1 << 24) | (0xf << 28))
+
+/*
+ * XHCI Register Space.
+ */
+struct xhci_hccr {
+	uint32_t cr_capbase;
+	uint32_t cr_hcsparams1;
+	uint32_t cr_hcsparams2;
+	uint32_t cr_hcsparams3;
+	uint32_t cr_hccparams;
+	uint32_t cr_dboff;
+	uint32_t cr_rtsoff;
+
+/* hc_capbase bitmasks */
+/* bits 7:0 - how long is the Capabilities register */
+#define HC_LENGTH(p)		XHCI_HC_LENGTH(p)
+/* bits 31:16	*/
+#define HC_VERSION(p)		(((p) >> 16) & 0xffff)
+
+/* HCSPARAMS1 - hcs_params1 - bitmasks */
+/* bits 0:7, Max Device Slots */
+#define HCS_MAX_SLOTS(p)	(((p) >> 0) & 0xff)
+#define HCS_SLOTS_MASK		0xff
+/* bits 8:18, Max Interrupters */
+#define HCS_MAX_INTRS(p)	(((p) >> 8) & 0x7ff)
+/* bits 24:31, Max Ports - max value is 0x7F = 127 ports */
+#define HCS_MAX_PORTS_SHIFT	24
+#define HCS_MAX_PORTS_MASK	(0x7f << HCS_MAX_PORTS_SHIFT)
+#define HCS_MAX_PORTS(p)	(((p) >> 24) & 0x7f)
+
+/* HCSPARAMS2 - hcs_params2 - bitmasks */
+/* bits 0:3, frames or uframes that SW needs to queue transactions
+ * ahead of the HW to meet periodic deadlines */
+#define HCS_IST(p)		(((p) >> 0) & 0xf)
+/* bits 4:7, max number of Event Ring segments */
+#define HCS_ERST_MAX(p)		(((p) >> 4) & 0xf)
+/* bit 26 Scratchpad restore - for save/restore HW state - not used yet */
+/* bits 27:31 number of Scratchpad buffers SW must allocate for the HW */
+#define HCS_MAX_SCRATCHPAD(p)   (((p) >> 27) & 0x1f)
+
+/* HCSPARAMS3 - hcs_params3 - bitmasks */
+/* bits 0:7, Max U1 to U0 latency for the roothub ports */
+#define HCS_U1_LATENCY(p)	(((p) >> 0) & 0xff)
+/* bits 16:31, Max U2 to U0 latency for the roothub ports */
+#define HCS_U2_LATENCY(p)	(((p) >> 16) & 0xffff)
+
+/* HCCPARAMS - hcc_params - bitmasks */
+/* true: HC can use 64-bit address pointers */
+#define HCC_64BIT_ADDR(p)	((p) & (1 << 0))
+/* true: HC can do bandwidth negotiation */
+#define HCC_BANDWIDTH_NEG(p)	((p) & (1 << 1))
+/* true: HC uses 64-byte Device Context structures
+ * FIXME 64-byte context structures aren't supported yet.
+ */
+#define HCC_64BYTE_CONTEXT(p)	((p) & (1 << 2))
+/* true: HC has port power switches */
+#define HCC_PPC(p)		((p) & (1 << 3))
+/* true: HC has port indicators */
+#define HCS_INDICATOR(p)	((p) & (1 << 4))
+/* true: HC has Light HC Reset Capability */
+#define HCC_LIGHT_RESET(p)	((p) & (1 << 5))
+/* true: HC supports latency tolerance messaging */
+#define HCC_LTC(p)		((p) & (1 << 6))
+/* true: no secondary Stream ID Support */
+#define HCC_NSS(p)		((p) & (1 << 7))
+/* Max size for Primary Stream Arrays - 2^(n+1), where n is bits 12:15 */
+#define HCC_MAX_PSA(p)		(1 << ((((p) >> 12) & 0xf) + 1))
+/* Extended Capabilities pointer from PCI base - section 5.3.6 */
+#define HCC_EXT_CAPS(p)		XHCI_HCC_EXT_CAPS(p)
+
+/* db_off bitmask - bits 0:1 reserved */
+#define	DBOFF_MASK	(~0x3)
+
+/* run_regs_off bitmask - bits 0:4 reserved */
+#define	RTSOFF_MASK	(~0x1f)
+
+};
+
+struct xhci_hcor_port_regs {
+	volatile uint32_t or_portsc;
+	volatile uint32_t or_portpmsc;
+	volatile uint32_t or_portli;
+	volatile uint32_t reserved_3;
+};
+
+struct xhci_hcor {
+	volatile uint32_t or_usbcmd;
+	volatile uint32_t or_usbsts;
+	volatile uint32_t or_pagesize;
+	volatile uint32_t reserved_0[2];
+	volatile uint32_t or_dnctrl;
+	volatile uint64_t or_crcr;
+	volatile uint32_t reserved_1[4];
+	volatile uint64_t or_dcbaap;
+	volatile uint32_t or_config;
+	volatile uint32_t reserved_2[241];
+	struct xhci_hcor_port_regs portregs[CONFIG_SYS_USB_XHCI_MAX_ROOT_PORTS];
+
+	uint32_t reserved_4[CONFIG_SYS_USB_XHCI_MAX_ROOT_PORTS * 254];
+};
+
+/* USBCMD - USB command - command bitmasks */
+/* start/stop HC execution - do not write unless HC is halted*/
+#define CMD_RUN		XHCI_CMD_RUN
+/* Reset HC - resets internal HC state machine and all registers (except
+ * PCI config regs).  HC does NOT drive a USB reset on the downstream ports.
+ * The xHCI driver must reinitialize the xHC after setting this bit.
+ */
+#define CMD_RESET	(1 << 1)
+/* Event Interrupt Enable - a '1' allows interrupts from the host controller */
+#define CMD_EIE		XHCI_CMD_EIE
+/* Host System Error Interrupt Enable - get out-of-band signal for HC errors */
+#define CMD_HSEIE	XHCI_CMD_HSEIE
+/* bits 4:6 are reserved (and should be preserved on writes). */
+/* light reset (port status stays unchanged) - reset completed when this is 0 */
+#define CMD_LRESET	(1 << 7)
+/* host controller save/restore state. */
+#define CMD_CSS		(1 << 8)
+#define CMD_CRS		(1 << 9)
+/* Enable Wrap Event - '1' means xHC generates an event when MFINDEX wraps. */
+#define CMD_EWE		XHCI_CMD_EWE
+/* MFINDEX power management - '1' means xHC can stop MFINDEX counter if all root
+ * hubs are in U3 (selective suspend), disconnect, disabled, or powered-off.
+ * '0' means the xHC can power it off if all ports are in the disconnect,
+ * disabled, or powered-off state.
+ */
+#define CMD_PM_INDEX	(1 << 11)
+/* bits 12:31 are reserved (and should be preserved on writes). */
+
+/* USBSTS - USB status - status bitmasks */
+/* HC not running - set to 1 when run/stop bit is cleared. */
+#define STS_HALT	XHCI_STS_HALT
+/* serious error, e.g. PCI parity error.  The HC will clear the run/stop bit. */
+#define STS_FATAL	(1 << 2)
+/* event interrupt - clear this prior to clearing any IP flags in IR set*/
+#define STS_EINT	(1 << 3)
+/* port change detect */
+#define STS_PORT	(1 << 4)
+/* bits 5:7 reserved and zeroed */
+/* save state status - '1' means xHC is saving state */
+#define STS_SAVE	(1 << 8)
+/* restore state status - '1' means xHC is restoring state */
+#define STS_RESTORE	(1 << 9)
+/* true: save or restore error */
+#define STS_SRE		(1 << 10)
+/* true: Controller Not Ready to accept doorbell or op reg writes after reset */
+#define STS_CNR		XHCI_STS_CNR
+/* true: internal Host Controller Error - SW needs to reset and reinitialize */
+#define STS_HCE		(1 << 12)
+/* bits 13:31 reserved and should be preserved */
+
+/*
+ * DNCTRL - Device Notification Control Register - dev_notification bitmasks
+ * Generate a device notification event when the HC sees a transaction with a
+ * notification type that matches a bit set in this bit field.
+ */
+#define	DEV_NOTE_MASK		(0xffff)
+#define ENABLE_DEV_NOTE(x)	(1 << (x))
+/* Most of the device notification types should only be used for debug.
+ * SW does need to pay attention to function wake notifications.
+ */
+#define	DEV_NOTE_FWAKE		ENABLE_DEV_NOTE(1)
+
+/* CRCR - Command Ring Control Register - cmd_ring bitmasks */
+/* bit 0 is the command ring cycle state */
+/* stop ring operation after completion of the currently executing command */
+#define CMD_RING_PAUSE		(1 << 1)
+/* stop ring immediately - abort the currently executing command */
+#define CMD_RING_ABORT		(1 << 2)
+/* true: command ring is running */
+#define CMD_RING_RUNNING	(1 << 3)
+/* bits 4:5 reserved and should be preserved */
+/* Command Ring pointer - bit mask for the lower 32 bits. */
+#define CMD_RING_RSVD_BITS	(0x3f)
+
+/* CONFIG - Configure Register - config_reg bitmasks */
+/* bits 0:7 - maximum number of device slots enabled (NumSlotsEn) */
+#define MAX_DEVS(p)	((p) & 0xff)
+/* bits 8:31 - reserved and should be preserved */
+
+/* PORTSC - Port Status and Control Register - port_status_base bitmasks */
+/* true: device connected */
+#define PORT_CONNECT	(1 << 0)
+/* true: port enabled */
+#define PORT_PE		(1 << 1)
+/* bit 2 reserved and zeroed */
+/* true: port has an over-current condition */
+#define PORT_OC		(1 << 3)
+/* true: port reset signaling asserted */
+#define PORT_RESET	(1 << 4)
+/* Port Link State - bits 5:8
+ * A read gives the current link PM state of the port,
+ * a write with Link State Write Strobe set sets the link state.
+ */
+#define PORT_PLS_MASK	(0xf << 5)
+#define XDEV_U0		(0x0 << 5)
+#define XDEV_U2		(0x2 << 5)
+#define XDEV_U3		(0x3 << 5)
+#define XDEV_RESUME	(0xf << 5)
+/* true: port has power (see HCC_PPC) */
+#define PORT_POWER	(1 << 9)
+/* bits 10:13 indicate device speed:
+ * 0 - undefined speed - port hasn't be initialized by a reset yet
+ * 1 - full speed
+ * 2 - low speed
+ * 3 - high speed
+ * 4 - super speed
+ * 5-15 reserved
+ */
+#define DEV_SPEED_MASK		(0xf << 10)
+#define	XDEV_FS			(0x1 << 10)
+#define	XDEV_LS			(0x2 << 10)
+#define	XDEV_HS			(0x3 << 10)
+#define	XDEV_SS			(0x4 << 10)
+#define DEV_UNDEFSPEED(p)	(((p) & DEV_SPEED_MASK) == (0x0<<10))
+#define DEV_FULLSPEED(p)	(((p) & DEV_SPEED_MASK) == XDEV_FS)
+#define DEV_LOWSPEED(p)		(((p) & DEV_SPEED_MASK) == XDEV_LS)
+#define DEV_HIGHSPEED(p)	(((p) & DEV_SPEED_MASK) == XDEV_HS)
+#define DEV_SUPERSPEED(p)	(((p) & DEV_SPEED_MASK) == XDEV_SS)
+/* Bits 20:23 in the Slot Context are the speed for the device */
+#define	SLOT_SPEED_FS		(XDEV_FS << 10)
+#define	SLOT_SPEED_LS		(XDEV_LS << 10)
+#define	SLOT_SPEED_HS		(XDEV_HS << 10)
+#define	SLOT_SPEED_SS		(XDEV_SS << 10)
+/* Port Indicator Control */
+#define PORT_LED_OFF	(0 << 14)
+#define PORT_LED_AMBER	(1 << 14)
+#define PORT_LED_GREEN	(2 << 14)
+#define PORT_LED_MASK	(3 << 14)
+/* Port Link State Write Strobe - set this when changing link state */
+#define PORT_LINK_STROBE	(1 << 16)
+/* true: connect status change */
+#define PORT_CSC	(1 << 17)
+/* true: port enable change */
+#define PORT_PEC	(1 << 18)
+/* true: warm reset for a USB 3.0 device is done.  A "hot" reset puts the port
+ * into an enabled state, and the device into the default state.  A "warm" reset
+ * also resets the link, forcing the device through the link training sequence.
+ * SW can also look at the Port Reset register to see when warm reset is done.
+ */
+#define PORT_WRC	(1 << 19)
+/* true: over-current change */
+#define PORT_OCC	(1 << 20)
+/* true: reset change - 1 to 0 transition of PORT_RESET */
+#define PORT_RC		(1 << 21)
+/* port link status change - set on some port link state transitions:
+ *  Transition				Reason
+ *  --------------------------------------------------------------------------
+ *  - U3 to Resume		Wakeup signaling from a device
+ *  - Resume to Recovery to U0	USB 3.0 device resume
+ *  - Resume to U0		USB 2.0 device resume
+ *  - U3 to Recovery to U0	Software resume of USB 3.0 device complete
+ *  - U3 to U0			Software resume of USB 2.0 device complete
+ *  - U2 to U0			L1 resume of USB 2.1 device complete
+ *  - U0 to U0 (???)		L1 entry rejection by USB 2.1 device
+ *  - U0 to disabled		L1 entry error with USB 2.1 device
+ *  - Any state to inactive	Error on USB 3.0 port
+ */
+#define PORT_PLC	(1 << 22)
+/* port configure error change - port failed to configure its link partner */
+#define PORT_CEC	(1 << 23)
+/* bit 24 reserved */
+/* wake on connect (enable) */
+#define PORT_WKCONN_E	(1 << 25)
+/* wake on disconnect (enable) */
+#define PORT_WKDISC_E	(1 << 26)
+/* wake on over-current (enable) */
+#define PORT_WKOC_E	(1 << 27)
+/* bits 28:29 reserved */
+/* true: device is removable - for USB 3.0 roothub emulation */
+#define PORT_DEV_REMOVE	(1 << 30)
+/* Initiate a warm port reset - complete when PORT_WRC is '1' */
+#define PORT_WR		(1 << 31)
+
+/* We mark duplicate entries with -1 */
+#define DUPLICATE_ENTRY ((u8)(-1))
+
+/* Port Power Management Status and Control - port_power_base bitmasks */
+/* Inactivity timer value for transitions into U1, in microseconds.
+ * Timeout can be up to 127us.  0xFF means an infinite timeout.
+ */
+#define PORT_U1_TIMEOUT(p)	((p) & 0xff)
+/* Inactivity timer value for transitions into U2 */
+#define PORT_U2_TIMEOUT(p)	(((p) & 0xff) << 8)
+/* Bits 24:31 for port testing */
+
+/* USB2 Protocol PORTSPMSC */
+#define	PORT_L1S_MASK		7
+#define	PORT_L1S_SUCCESS	1
+#define	PORT_RWE		(1 << 3)
+#define	PORT_HIRD(p)		(((p) & 0xf) << 4)
+#define	PORT_HIRD_MASK		(0xf << 4)
+#define	PORT_L1DS(p)		(((p) & 0xff) << 8)
+#define	PORT_HLE		(1 << 16)
+
+/**
+* struct xhci_intr_reg - Interrupt Register Set
+* @irq_pending:	IMAN - Interrupt Management Register.  Used to enable
+*			interrupts and check for pending interrupts.
+* @irq_control:	IMOD - Interrupt Moderation Register.
+*			Used to throttle interrupts.
+* @erst_size:		Number of segments in the
+			Event Ring Segment Table (ERST).
+* @erst_base:		ERST base address.
+* @erst_dequeue:	Event ring dequeue pointer.
+*
+* Each interrupter (defined by a MSI-X vector) has an event ring and an Event
+* Ring Segment Table (ERST) associated with it.
+* The event ring is comprised of  multiple segments of the same size.
+* The HC places events on the ring and  "updates the Cycle bit in the TRBs to
+* indicate to software the current  position of the Enqueue Pointer."
+* The HCD (Linux) processes those events and  updates the dequeue pointer.
+*/
+struct xhci_intr_reg {
+	volatile __le32	irq_pending;
+	volatile __le32	irq_control;
+	volatile __le32	erst_size;
+	volatile __le32	rsvd;
+	volatile __le64	erst_base;
+	volatile __le64	erst_dequeue;
+};
+
+/* irq_pending bitmasks */
+#define	ER_IRQ_PENDING(p)	((p) & 0x1)
+/* bits 2:31 need to be preserved */
+/* THIS IS BUGGY - FIXME - IP IS WRITE 1 TO CLEAR */
+#define	ER_IRQ_CLEAR(p)		((p) & 0xfffffffe)
+#define	ER_IRQ_ENABLE(p)	((ER_IRQ_CLEAR(p)) | 0x2)
+#define	ER_IRQ_DISABLE(p)	((ER_IRQ_CLEAR(p)) & ~(0x2))
+
+/* irq_control bitmasks */
+/* Minimum interval between interrupts (in 250ns intervals).  The interval
+ * between interrupts will be longer if there are no events on the event ring.
+ * Default is 4000 (1 ms).
+ */
+#define ER_IRQ_INTERVAL_MASK	(0xffff)
+/* Counter used to count down the time to the next interrupt - HW use only */
+#define ER_IRQ_COUNTER_MASK	(0xffff << 16)
+
+/* erst_size bitmasks */
+/* Preserve bits 16:31 of erst_size */
+#define	ERST_SIZE_MASK		(0xffff << 16)
+
+/* erst_dequeue bitmasks */
+/* Dequeue ERST Segment Index (DESI) - Segment number (or alias)
+ * where the current dequeue pointer lies.  This is an optional HW hint.
+ */
+#define ERST_DESI_MASK		(0x7)
+/* Event Handler Busy (EHB) - is the event ring scheduled to be serviced by
+ * a work queue (or delayed service routine)?
+ */
+#define ERST_EHB		(1 << 3)
+#define ERST_PTR_MASK		(0xf)
+
+/**
+ * struct xhci_run_regs
+ * @microframe_index:	MFINDEX - current microframe number
+ *
+ * Section 5.5 Host Controller Runtime Registers:
+ * "Software should read and write these registers using only Dword (32 bit)
+ * or larger accesses"
+ */
+struct xhci_run_regs {
+	__le32			microframe_index;
+	__le32			rsvd[7];
+	struct xhci_intr_reg	ir_set[128];
+};
+
+/**
+ * struct doorbell_array
+ *
+ * Bits  0 -  7: Endpoint target
+ * Bits  8 - 15: RsvdZ
+ * Bits 16 - 31: Stream ID
+ *
+ * Section 5.6
+ */
+struct xhci_doorbell_array {
+	volatile __le32	doorbell[256];
+};
+
+#define DB_VALUE(ep, stream)	((((ep) + 1) & 0xff) | ((stream) << 16))
+#define DB_VALUE_HOST		0x00000000
+
+/**
+ * struct xhci_protocol_caps
+ * @revision:		major revision, minor revision, capability ID,
+ *			and next capability pointer.
+ * @name_string:	Four ASCII characters to say which spec this xHC
+ *			follows, typically "USB ".
+ * @port_info:		Port offset, count, and protocol-defined information.
+ */
+struct xhci_protocol_caps {
+	u32	revision;
+	u32	name_string;
+	u32	port_info;
+};
+
+#define	XHCI_EXT_PORT_MAJOR(x)	(((x) >> 24) & 0xff)
+#define	XHCI_EXT_PORT_OFF(x)	((x) & 0xff)
+#define	XHCI_EXT_PORT_COUNT(x)	(((x) >> 8) & 0xff)
+
+/**
+ * struct xhci_container_ctx
+ * @type: Type of context.  Used to calculated offsets to contained contexts.
+ * @size: Size of the context data
+ * @bytes: The raw context data given to HW
+ * @dma: dma address of the bytes
+ *
+ * Represents either a Device or Input context.  Holds a pointer to the raw
+ * memory used for the context (bytes) and dma address of it (dma).
+ */
+struct xhci_container_ctx {
+	unsigned type;
+#define XHCI_CTX_TYPE_DEVICE  0x1
+#define XHCI_CTX_TYPE_INPUT   0x2
+
+	int size;
+	u8 *bytes;
+};
+
+/**
+ * struct xhci_slot_ctx
+ * @dev_info:	Route string, device speed, hub info, and last valid endpoint
+ * @dev_info2:	Max exit latency for device number, root hub port number
+ * @tt_info:	tt_info is used to construct split transaction tokens
+ * @dev_state:	slot state and device address
+ *
+ * Slot Context - section 6.2.1.1.  This assumes the HC uses 32-byte context
+ * structures.  If the HC uses 64-byte contexts, there is an additional 32 bytes
+ * reserved at the end of the slot context for HC internal use.
+ */
+struct xhci_slot_ctx {
+	__le32	dev_info;
+	__le32	dev_info2;
+	__le32	tt_info;
+	__le32	dev_state;
+	/* offset 0x10 to 0x1f reserved for HC internal use */
+	__le32	reserved[4];
+};
+
+/* dev_info bitmasks */
+/* Route String - 0:19 */
+#define ROUTE_STRING_MASK	(0xfffff)
+/* Device speed - values defined by PORTSC Device Speed field - 20:23 */
+#define DEV_SPEED		(0xf << 20)
+/* bit 24 reserved */
+/* Is this LS/FS device connected through a HS hub? - bit 25 */
+#define DEV_MTT			(0x1 << 25)
+/* Set if the device is a hub - bit 26 */
+#define DEV_HUB			(0x1 << 26)
+/* Index of the last valid endpoint context in this device context - 27:31 */
+#define LAST_CTX_MASK		(0x1f << 27)
+#define LAST_CTX(p)		((p) << 27)
+#define LAST_CTX_TO_EP_NUM(p)	(((p) >> 27) - 1)
+#define SLOT_FLAG		(1 << 0)
+#define EP0_FLAG		(1 << 1)
+
+/* dev_info2 bitmasks */
+/* Max Exit Latency (ms) - worst case time to wake up all links in dev path */
+#define MAX_EXIT			(0xffff)
+/* Root hub port number that is needed to access the USB device */
+#define ROOT_HUB_PORT(p)		(((p) & 0xff) << 16)
+#define ROOT_HUB_PORT_MASK		(0xff)
+#define ROOT_HUB_PORT_SHIFT		(16)
+#define DEVINFO_TO_ROOT_HUB_PORT(p)	(((p) >> 16) & 0xff)
+/* Maximum number of ports under a hub device */
+#define XHCI_MAX_PORTS(p)		(((p) & 0xff) << 24)
+
+/* tt_info bitmasks */
+/*
+ * TT Hub Slot ID - for low or full speed devices attached to a high-speed hub
+ * The Slot ID of the hub that isolates the high speed signaling from
+ * this low or full-speed device.  '0' if attached to root hub port.
+ */
+#define TT_SLOT			(0xff)
+/*
+ * The number of the downstream facing port of the high-speed hub
+ * '0' if the device is not low or full speed.
+ */
+#define TT_PORT			(0xff << 8)
+#define TT_THINK_TIME(p)	(((p) & 0x3) << 16)
+
+/* dev_state bitmasks */
+/* USB device address - assigned by the HC */
+#define DEV_ADDR_MASK	(0xff)
+/* bits 8:26 reserved */
+/* Slot state */
+#define SLOT_STATE		(0x1f << 27)
+#define GET_SLOT_STATE(p)	(((p) & (0x1f << 27)) >> 27)
+
+#define SLOT_STATE_DISABLED	0
+#define SLOT_STATE_ENABLED	SLOT_STATE_DISABLED
+#define SLOT_STATE_DEFAULT	1
+#define SLOT_STATE_ADDRESSED	2
+#define SLOT_STATE_CONFIGURED	3
+
+/**
+ * struct xhci_ep_ctx
+ * @ep_info:	endpoint state, streams, mult, and interval information.
+ * @ep_info2:	information on endpoint type, max packet size, max burst size,
+ *		error count, and whether the HC will force an event for all
+ *		transactions.
+ * @deq:	64-bit ring dequeue pointer address.  If the endpoint only
+ *		defines one stream, this points to the endpoint transfer ring.
+ *		Otherwise, it points to a stream context array, which has a
+ *		ring pointer for each flow.
+ * @tx_info:
+ *		Average TRB lengths for the endpoint ring and
+ *		max payload within an Endpoint Service Interval Time (ESIT).
+ *
+ * Endpoint Context - section 6.2.1.2.This assumes the HC uses 32-byte context
+ * structures.If the HC uses 64-byte contexts, there is an additional 32 bytes
+ * reserved at the end of the endpoint context for HC internal use.
+ */
+struct xhci_ep_ctx {
+	__le32	ep_info;
+	__le32	ep_info2;
+	__le64	deq;
+	__le32	tx_info;
+	/* offset 0x14 - 0x1f reserved for HC internal use */
+	__le32	reserved[3];
+};
+
+/* ep_info bitmasks */
+/*
+ * Endpoint State - bits 0:2
+ * 0 - disabled
+ * 1 - running
+ * 2 - halted due to halt condition - ok to manipulate endpoint ring
+ * 3 - stopped
+ * 4 - TRB error
+ * 5-7 - reserved
+ */
+#define EP_STATE_MASK		(0xf)
+#define EP_STATE_DISABLED	0
+#define EP_STATE_RUNNING	1
+#define EP_STATE_HALTED		2
+#define EP_STATE_STOPPED	3
+#define EP_STATE_ERROR		4
+/* Mult - Max number of burtst within an interval, in EP companion desc. */
+#define EP_MULT(p)		(((p) & 0x3) << 8)
+#define CTX_TO_EP_MULT(p)	(((p) >> 8) & 0x3)
+/* bits 10:14 are Max Primary Streams */
+/* bit 15 is Linear Stream Array */
+/* Interval - period between requests to an endpoint - 125u increments. */
+#define EP_INTERVAL(p)			(((p) & 0xff) << 16)
+#define EP_INTERVAL_TO_UFRAMES(p)	(1 << (((p) >> 16) & 0xff))
+#define CTX_TO_EP_INTERVAL(p)		(((p) >> 16) & 0xff)
+#define EP_MAXPSTREAMS_MASK		(0x1f << 10)
+#define EP_MAXPSTREAMS(p)		(((p) << 10) & EP_MAXPSTREAMS_MASK)
+/* Endpoint is set up with a Linear Stream Array (vs. Secondary Stream Array) */
+#define	EP_HAS_LSA			(1 << 15)
+
+/* ep_info2 bitmasks */
+/*
+ * Force Event - generate transfer events for all TRBs for this endpoint
+ * This will tell the HC to ignore the IOC and ISP flags (for debugging only).
+ */
+#define	FORCE_EVENT		(0x1)
+#define ERROR_COUNT(p)		(((p) & 0x3) << 1)
+#define ERROR_COUNT_SHIFT	(1)
+#define ERROR_COUNT_MASK	(0x3)
+#define CTX_TO_EP_TYPE(p)	(((p) >> 3) & 0x7)
+#define EP_TYPE(p)		((p) << 3)
+#define EP_TYPE_SHIFT		(3)
+#define ISOC_OUT_EP		1
+#define BULK_OUT_EP		2
+#define INT_OUT_EP		3
+#define CTRL_EP			4
+#define ISOC_IN_EP		5
+#define BULK_IN_EP		6
+#define INT_IN_EP		7
+/* bit 6 reserved */
+/* bit 7 is Host Initiate Disable - for disabling stream selection */
+#define MAX_BURST(p)		(((p)&0xff) << 8)
+#define MAX_BURST_MASK		(0xff)
+#define MAX_BURST_SHIFT		(8)
+#define CTX_TO_MAX_BURST(p)	(((p) >> 8) & 0xff)
+#define MAX_PACKET(p)		(((p)&0xffff) << 16)
+#define MAX_PACKET_MASK		(0xffff)
+#define MAX_PACKET_DECODED(p)	(((p) >> 16) & 0xffff)
+#define MAX_PACKET_SHIFT	(16)
+
+/* Get max packet size from ep desc. Bit 10..0 specify the max packet size.
+ * USB2.0 spec 9.6.6.
+ */
+#define GET_MAX_PACKET(p)	((p) & 0x7ff)
+
+/* tx_info bitmasks */
+#define AVG_TRB_LENGTH_FOR_EP(p)	((p) & 0xffff)
+#define MAX_ESIT_PAYLOAD_FOR_EP(p)	(((p) & 0xffff) << 16)
+#define CTX_TO_MAX_ESIT_PAYLOAD(p)	(((p) >> 16) & 0xffff)
+
+/* deq bitmasks */
+#define EP_CTX_CYCLE_MASK		(1 << 0)
+
+
+/**
+ * struct xhci_input_control_context
+ * Input control context; see section 6.2.5.
+ *
+ * @drop_context:	set the bit of the endpoint context you want to disable
+ * @add_context:	set the bit of the endpoint context you want to enable
+ */
+struct xhci_input_control_ctx {
+	volatile __le32	drop_flags;
+	volatile __le32	add_flags;
+	__le32	rsvd2[6];
+};
+
+
+/**
+ * struct xhci_device_context_array
+ * @dev_context_ptr	array of 64-bit DMA addresses for device contexts
+ */
+struct xhci_device_context_array {
+	/* 64-bit device addresses; we only write 32-bit addresses */
+	__le64			dev_context_ptrs[MAX_HC_SLOTS];
+};
+/* TODO: write function to set the 64-bit device DMA address */
+/*
+ * TODO: change this to be dynamically sized at HC mem init time since the HC
+ * might not be able to handle the maximum number of devices possible.
+ */
+
+
+struct xhci_transfer_event {
+	/* 64-bit buffer address, or immediate data */
+	__le64	buffer;
+	__le32	transfer_len;
+	/* This field is interpreted differently based on the type of TRB */
+	volatile __le32	flags;
+};
+
+/* Transfer event TRB length bit mask */
+/* bits 0:23 */
+#define EVENT_TRB_LEN(p)	((p) & 0xffffff)
+
+/** Transfer Event bit fields **/
+#define	TRB_TO_EP_ID(p)		(((p) >> 16) & 0x1f)
+
+/* Completion Code - only applicable for some types of TRBs */
+#define	COMP_CODE_MASK		(0xff << 24)
+#define	COMP_CODE_SHIFT		(24)
+#define GET_COMP_CODE(p)	(((p) & COMP_CODE_MASK) >> 24)
+
+typedef enum {
+	COMP_SUCCESS = 1,
+	/* Data Buffer Error */
+	COMP_DB_ERR, /* 2 */
+	/* Babble Detected Error */
+	COMP_BABBLE, /* 3 */
+	/* USB Transaction Error */
+	COMP_TX_ERR, /* 4 */
+	/* TRB Error - some TRB field is invalid */
+	COMP_TRB_ERR, /* 5 */
+	/* Stall Error - USB device is stalled */
+	COMP_STALL, /* 6 */
+	/* Resource Error - HC doesn't have memory for that device configuration */
+	COMP_ENOMEM, /* 7 */
+	/* Bandwidth Error - not enough room in schedule for this dev config */
+	COMP_BW_ERR, /* 8 */
+	/* No Slots Available Error - HC ran out of device slots */
+	COMP_ENOSLOTS, /* 9 */
+	/* Invalid Stream Type Error */
+	COMP_STREAM_ERR, /* 10 */
+	/* Slot Not Enabled Error - doorbell rung for disabled device slot */
+	COMP_EBADSLT, /* 11 */
+	/* Endpoint Not Enabled Error */
+	COMP_EBADEP,/* 12 */
+	/* Short Packet */
+	COMP_SHORT_TX, /* 13 */
+	/* Ring Underrun - doorbell rung for an empty isoc OUT ep ring */
+	COMP_UNDERRUN, /* 14 */
+	/* Ring Overrun - isoc IN ep ring is empty when ep is scheduled to RX */
+	COMP_OVERRUN, /* 15 */
+	/* Virtual Function Event Ring Full Error */
+	COMP_VF_FULL, /* 16 */
+	/* Parameter Error - Context parameter is invalid */
+	COMP_EINVAL, /* 17 */
+	/* Bandwidth Overrun Error - isoc ep exceeded its allocated bandwidth */
+	COMP_BW_OVER,/* 18 */
+	/* Context State Error - illegal context state transition requested */
+	COMP_CTX_STATE,/* 19 */
+	/* No Ping Response Error - HC didn't get PING_RESPONSE in time to TX */
+	COMP_PING_ERR,/* 20 */
+	/* Event Ring is full */
+	COMP_ER_FULL,/* 21 */
+	/* Incompatible Device Error */
+	COMP_DEV_ERR,/* 22 */
+	/* Missed Service Error - HC couldn't service an isoc ep within interval */
+	COMP_MISSED_INT,/* 23 */
+	/* Successfully stopped command ring */
+	COMP_CMD_STOP, /* 24 */
+	/* Successfully aborted current command and stopped command ring */
+	COMP_CMD_ABORT, /* 25 */
+	/* Stopped - transfer was terminated by a stop endpoint command */
+	COMP_STOP,/* 26 */
+	/* Same as COMP_EP_STOPPED, but the transferred length in the event
+	 * is invalid */
+	COMP_STOP_INVAL, /* 27*/
+	/* Control Abort Error - Debug Capability - control pipe aborted */
+	COMP_DBG_ABORT, /* 28 */
+	/* Max Exit Latency Too Large Error */
+	COMP_MEL_ERR,/* 29 */
+	/* TRB type 30 reserved */
+	/* Isoc Buffer Overrun - an isoc IN ep sent more data than could fit in TD */
+	COMP_BUFF_OVER = 31,
+	/* Event Lost Error - xHC has an "internal event overrun condition" */
+	COMP_ISSUES, /* 32 */
+	/* Undefined Error - reported when other error codes don't apply */
+	COMP_UNKNOWN, /* 33 */
+	/* Invalid Stream ID Error */
+	COMP_STRID_ERR, /* 34 */
+	/* Secondary Bandwidth Error - may be returned by a Configure Endpoint cmd */
+	COMP_2ND_BW_ERR, /* 35 */
+	/* Split Transaction Error */
+	COMP_SPLIT_ERR /* 36 */
+
+} xhci_comp_code;
+
+struct xhci_link_trb {
+	/* 64-bit segment pointer*/
+	volatile __le64 segment_ptr;
+	volatile __le32 intr_target;
+	volatile __le32 control;
+};
+
+/* control bitfields */
+#define LINK_TOGGLE (0x1 << 1)
+
+/* Command completion event TRB */
+struct xhci_event_cmd {
+	/* Pointer to command TRB, or the value passed by the event data trb */
+	volatile __le64 cmd_trb;
+	volatile __le32 status;
+	volatile __le32 flags;
+};
+
+/* flags bitmasks */
+/* bits 16:23 are the virtual function ID */
+/* bits 24:31 are the slot ID */
+#define	TRB_TO_SLOT_ID(p)		(((p) & (0xff << 24)) >> 24)
+#define	TRB_TO_SLOT_ID_SHIFT		(24)
+#define	TRB_TO_SLOT_ID_MASK		(0xff << TRB_TO_SLOT_ID_SHIFT)
+#define	SLOT_ID_FOR_TRB(p)		(((p) & 0xff) << 24)
+#define	SLOT_ID_FOR_TRB_MASK		(0xff)
+#define	SLOT_ID_FOR_TRB_SHIFT		(24)
+
+/* Stop Endpoint TRB - ep_index to endpoint ID for this TRB */
+#define TRB_TO_EP_INDEX(p)		((((p) & (0x1f << 16)) >> 16) - 1)
+#define	EP_ID_FOR_TRB(p)		((((p) + 1) & 0x1f) << 16)
+
+#define SUSPEND_PORT_FOR_TRB(p)		(((p) & 1) << 23)
+#define TRB_TO_SUSPEND_PORT(p)		(((p) & (1 << 23)) >> 23)
+#define LAST_EP_INDEX			30
+
+/* Set TR Dequeue Pointer command TRB fields */
+#define TRB_TO_STREAM_ID(p)		((((p) & (0xffff << 16)) >> 16))
+#define STREAM_ID_FOR_TRB(p)		((((p)) & 0xffff) << 16)
+
+
+/* Port Status Change Event TRB fields */
+/* Port ID - bits 31:24 */
+#define GET_PORT_ID(p)			(((p) & (0xff << 24)) >> 24)
+#define	PORT_ID_SHIFT			(24)
+#define	PORT_ID_MASK			(0xff << PORT_ID_SHIFT)
+
+/* Normal TRB fields */
+/* transfer_len bitmasks - bits 0:16 */
+#define	TRB_LEN(p)			((p) & 0x1ffff)
+#define	TRB_LEN_MASK			(0x1ffff)
+/* Interrupter Target - which MSI-X vector to target the completion event at */
+#define	TRB_INTR_TARGET_SHIFT		(22)
+#define	TRB_INTR_TARGET_MASK		(0x3ff)
+#define TRB_INTR_TARGET(p)		(((p) & 0x3ff) << 22)
+#define GET_INTR_TARGET(p)		(((p) >> 22) & 0x3ff)
+#define TRB_TBC(p)			(((p) & 0x3) << 7)
+#define TRB_TLBPC(p)			(((p) & 0xf) << 16)
+
+/* Cycle bit - indicates TRB ownership by HC or HCD */
+#define TRB_CYCLE		(1<<0)
+/*
+ * Force next event data TRB to be evaluated before task switch.
+ * Used to pass OS data back after a TD completes.
+ */
+#define TRB_ENT			(1<<1)
+/* Interrupt on short packet */
+#define TRB_ISP			(1<<2)
+/* Set PCIe no snoop attribute */
+#define TRB_NO_SNOOP		(1<<3)
+/* Chain multiple TRBs into a TD */
+#define TRB_CHAIN		(1<<4)
+/* Interrupt on completion */
+#define TRB_IOC			(1<<5)
+/* The buffer pointer contains immediate data */
+#define TRB_IDT			(1<<6)
+
+/* Block Event Interrupt */
+#define	TRB_BEI			(1<<9)
+
+/* Control transfer TRB specific fields */
+#define TRB_DIR_IN		(1<<16)
+#define	TRB_TX_TYPE(p)		((p) << 16)
+#define	TRB_TX_TYPE_SHIFT	(16)
+#define	TRB_DATA_OUT		2
+#define	TRB_DATA_IN		3
+
+/* Isochronous TRB specific fields */
+#define TRB_SIA			(1 << 31)
+
+struct xhci_generic_trb {
+	volatile __le32 field[4];
+};
+
+union xhci_trb {
+	struct xhci_link_trb		link;
+	struct xhci_transfer_event	trans_event;
+	struct xhci_event_cmd		event_cmd;
+	struct xhci_generic_trb		generic;
+};
+
+/* TRB bit mask */
+#define	TRB_TYPE_BITMASK	(0xfc00)
+#define TRB_TYPE(p)		((p) << 10)
+#define TRB_TYPE_SHIFT		(10)
+#define TRB_FIELD_TO_TYPE(p)	(((p) & TRB_TYPE_BITMASK) >> 10)
+
+/* TRB type IDs */
+typedef enum {
+	/* bulk, interrupt, isoc scatter/gather, and control data stage */
+	TRB_NORMAL = 1,
+	/* setup stage for control transfers */
+	TRB_SETUP, /* 2 */
+	/* data stage for control transfers */
+	TRB_DATA, /* 3 */
+	/* status stage for control transfers */
+	TRB_STATUS, /* 4 */
+	/* isoc transfers */
+	TRB_ISOC, /* 5 */
+	/* TRB for linking ring segments */
+	TRB_LINK, /* 6 */
+	/* TRB for EVENT DATA */
+	TRB_EVENT_DATA, /* 7 */
+	/* Transfer Ring No-op (not for the command ring) */
+	TRB_TR_NOOP, /* 8 */
+	/* Command TRBs */
+	/* Enable Slot Command */
+	TRB_ENABLE_SLOT, /* 9 */
+	/* Disable Slot Command */
+	TRB_DISABLE_SLOT, /* 10 */
+	/* Address Device Command */
+	TRB_ADDR_DEV, /* 11 */
+	/* Configure Endpoint Command */
+	TRB_CONFIG_EP, /* 12 */
+	/* Evaluate Context Command */
+	TRB_EVAL_CONTEXT, /* 13 */
+	/* Reset Endpoint Command */
+	TRB_RESET_EP, /* 14 */
+	/* Stop Transfer Ring Command */
+	TRB_STOP_RING, /* 15 */
+	/* Set Transfer Ring Dequeue Pointer Command */
+	TRB_SET_DEQ, /* 16 */
+	/* Reset Device Command */
+	TRB_RESET_DEV, /* 17 */
+	/* Force Event Command (opt) */
+	TRB_FORCE_EVENT, /* 18 */
+	/* Negotiate Bandwidth Command (opt) */
+	TRB_NEG_BANDWIDTH, /* 19 */
+	/* Set Latency Tolerance Value Command (opt) */
+	TRB_SET_LT, /* 20 */
+	/* Get port bandwidth Command */
+	TRB_GET_BW, /* 21 */
+	/* Force Header Command - generate a transaction or link management packet */
+	TRB_FORCE_HEADER, /* 22 */
+	/* No-op Command - not for transfer rings */
+	TRB_CMD_NOOP, /* 23 */
+	/* TRB IDs 24-31 reserved */
+	/* Event TRBS */
+	/* Transfer Event */
+	TRB_TRANSFER = 32,
+	/* Command Completion Event */
+	TRB_COMPLETION, /* 33 */
+	/* Port Status Change Event */
+	TRB_PORT_STATUS, /* 34 */
+	/* Bandwidth Request Event (opt) */
+	TRB_BANDWIDTH_EVENT, /* 35 */
+	/* Doorbell Event (opt) */
+	TRB_DOORBELL, /* 36 */
+	/* Host Controller Event */
+	TRB_HC_EVENT, /* 37 */
+	/* Device Notification Event - device sent function wake notification */
+	TRB_DEV_NOTE, /* 38 */
+	/* MFINDEX Wrap Event - microframe counter wrapped */
+	TRB_MFINDEX_WRAP, /* 39 */
+	/* TRB IDs 40-47 reserved, 48-63 is vendor-defined */
+	/* Nec vendor-specific command completion event. */
+	TRB_NEC_CMD_COMP = 48, /* 48 */
+	/* Get NEC firmware revision. */
+	TRB_NEC_GET_FW, /* 49 */
+} trb_type;
+
+#define TRB_TYPE_LINK(x)	(((x) & TRB_TYPE_BITMASK) == TRB_TYPE(TRB_LINK))
+/* Above, but for __le32 types -- can avoid work by swapping constants: */
+#define TRB_TYPE_LINK_LE32(x)	(((x) & cpu_to_le32(TRB_TYPE_BITMASK)) == \
+				 cpu_to_le32(TRB_TYPE(TRB_LINK)))
+#define TRB_TYPE_NOOP_LE32(x)	(((x) & cpu_to_le32(TRB_TYPE_BITMASK)) == \
+				 cpu_to_le32(TRB_TYPE(TRB_TR_NOOP)))
+
+/*
+ * TRBS_PER_SEGMENT must be a multiple of 4,
+ * since the command ring is 64-byte aligned.
+ * It must also be greater than 16.
+ */
+#define TRBS_PER_SEGMENT	64
+/* Allow two commands + a link TRB, along with any reserved command TRBs */
+#define MAX_RSVD_CMD_TRBS	(TRBS_PER_SEGMENT - 3)
+#define SEGMENT_SIZE		(TRBS_PER_SEGMENT*16)
+/* SEGMENT_SHIFT should be log2(SEGMENT_SIZE).
+ * Change this if you change TRBS_PER_SEGMENT!
+ */
+#define SEGMENT_SHIFT		10
+/* TRB buffer pointers can't cross 64KB boundaries */
+#define TRB_MAX_BUFF_SHIFT	16
+#define TRB_MAX_BUFF_SIZE	(1 << TRB_MAX_BUFF_SHIFT)
+
+struct xhci_segment {
+	union xhci_trb		*trbs;
+	/* private to HCD */
+	struct xhci_segment	*next;
+};
+
+struct xhci_ring {
+	struct xhci_segment	*first_seg;
+	union  xhci_trb		*enqueue;
+	struct xhci_segment	*enq_seg;
+	union  xhci_trb		*dequeue;
+	struct xhci_segment	*deq_seg;
+	/*
+	 * Write the cycle state into the TRB cycle field to give ownership of
+	 * the TRB to the host controller (if we are the producer), or to check
+	 * if we own the TRB (if we are the consumer).  See section 4.9.1.
+	 */
+	volatile u32		cycle_state;
+	unsigned int		num_segs;
+};
+
+struct xhci_erst_entry {
+	/* 64-bit event ring segment address */
+	__le64	seg_addr;
+	__le32	seg_size;
+	/* Set to zero */
+	__le32	rsvd;
+};
+
+struct xhci_erst {
+	struct xhci_erst_entry	*entries;
+	unsigned int		num_entries;
+	/* Num entries the ERST can contain */
+	unsigned int		erst_size;
+};
+
+/*
+ * Each segment table entry is 4*32bits long.  1K seems like an ok size:
+ * (1K bytes * 8bytes/bit) / (4*32 bits) = 64 segment entries in the table,
+ * meaning 64 ring segments.
+ * Initial allocated size of the ERST, in number of entries */
+#define	ERST_NUM_SEGS	3
+/* Initial number of event segment rings allocated */
+#define	ERST_ENTRIES	3
+/* Initial allocated size of the ERST, in number of entries */
+#define	ERST_SIZE	64
+/* Poll every 60 seconds */
+#define	POLL_TIMEOUT	60
+/* Stop endpoint command timeout (secs) for URB cancellation watchdog timer */
+#define XHCI_STOP_EP_CMD_TIMEOUT	5
+/* XXX: Make these module parameters */
+
+struct xhci_virt_ep {
+	struct xhci_ring		*ring;
+	unsigned int			ep_state;
+#define SET_DEQ_PENDING		(1 << 0)
+#define EP_HALTED		(1 << 1)	/* For stall handling */
+#define EP_HALT_PENDING		(1 << 2)	/* For URB cancellation */
+/* Transitioning the endpoint to using streams, don't enqueue URBs */
+#define EP_GETTING_STREAMS	(1 << 3)
+#define EP_HAS_STREAMS		(1 << 4)
+/* Transitioning the endpoint to not using streams, don't enqueue URBs */
+#define EP_GETTING_NO_STREAMS	(1 << 5)
+};
+
+#define CTX_SIZE(_hcc) (HCC_64BYTE_CONTEXT(_hcc) ? 64 : 32)
+
+struct xhci_virt_device {
+	struct usb_device		*udev;
+	/*
+	 * Commands to the hardware are passed an "input context" that
+	 * tells the hardware what to change in its data structures.
+	 * The hardware will return changes in an "output context" that
+	 * software must allocate for the hardware.  We need to keep
+	 * track of input and output contexts separately because
+	 * these commands might fail and we don't trust the hardware.
+	 */
+	struct xhci_container_ctx       *out_ctx;
+	/* Used for addressing devices and configuration changes */
+	struct xhci_container_ctx       *in_ctx;
+	/* Rings saved to ensure old alt settings can be re-instated */
+#define	XHCI_MAX_RINGS_CACHED	31
+	struct xhci_virt_ep		eps[31];
+};
+
+/* TODO: copied from ehci.h - can be refactored? */
+/* xHCI spec says all registers are little endian */
+static inline unsigned int xhci_readl(uint32_t volatile *regs)
+{
+	return readl(regs);
+}
+
+static inline void xhci_writel(uint32_t volatile *regs, const unsigned int val)
+{
+	writel(val, regs);
+}
+
+/*
+ * Registers should always be accessed with double word or quad word accesses.
+ * Some xHCI implementations may support 64-bit address pointers.  Registers
+ * with 64-bit address pointers should be written to with dword accesses by
+ * writing the low dword first (ptr[0]), then the high dword (ptr[1]) second.
+ * xHCI implementations that do not support 64-bit address pointers will ignore
+ * the high dword, and write order is irrelevant.
+ */
+static inline u64 xhci_readq(__le64 volatile *regs)
+{
+	__u32 *ptr = (__u32 *)regs;
+	u64 val_lo = readl(ptr);
+	u64 val_hi = readl(ptr + 1);
+	return val_lo + (val_hi << 32);
+}
+
+static inline void xhci_writeq(__le64 volatile *regs, const u64 val)
+{
+	__u32 *ptr = (__u32 *)regs;
+	u32 val_lo = lower_32_bits(val);
+	/* FIXME */
+	u32 val_hi = 0;
+	writel(val_lo, ptr);
+	writel(val_hi, ptr + 1);
+}
+
+int xhci_hcd_init(int index, struct xhci_hccr **ret_hccr,
+					struct xhci_hcor **ret_hcor);
+void xhci_hcd_stop(int index);
+
+
+/*************************************************************
+	EXTENDED CAPABILITY DEFINITIONS
+*************************************************************/
+/* Up to 16 ms to halt an HC */
+#define XHCI_MAX_HALT_USEC	(16*1000)
+/* HC not running - set to 1 when run/stop bit is cleared. */
+#define XHCI_STS_HALT		(1 << 0)
+
+/* HCCPARAMS offset from PCI base address */
+#define XHCI_HCC_PARAMS_OFFSET	0x10
+/* HCCPARAMS contains the first extended capability pointer */
+#define XHCI_HCC_EXT_CAPS(p)	(((p)>>16)&0xffff)
+
+/* Command and Status registers offset from the Operational Registers address */
+#define XHCI_CMD_OFFSET		0x00
+#define XHCI_STS_OFFSET		0x04
+
+#define XHCI_MAX_EXT_CAPS		50
+
+/* Capability Register */
+/* bits 7:0 - how long is the Capabilities register */
+#define XHCI_HC_LENGTH(p)	(((p) >> 00) & 0x00ff)
+
+/* Extended capability register fields */
+#define XHCI_EXT_CAPS_ID(p)	(((p) >> 0) & 0xff)
+#define XHCI_EXT_CAPS_NEXT(p)	(((p) >> 8) & 0xff)
+#define	XHCI_EXT_CAPS_VAL(p)	((p) >> 16)
+/* Extended capability IDs - ID 0 reserved */
+#define XHCI_EXT_CAPS_LEGACY	1
+#define XHCI_EXT_CAPS_PROTOCOL	2
+#define XHCI_EXT_CAPS_PM	3
+#define XHCI_EXT_CAPS_VIRT	4
+#define XHCI_EXT_CAPS_ROUTE	5
+/* IDs 6-9 reserved */
+#define XHCI_EXT_CAPS_DEBUG	10
+/* USB Legacy Support Capability - section 7.1.1 */
+#define XHCI_HC_BIOS_OWNED	(1 << 16)
+#define XHCI_HC_OS_OWNED	(1 << 24)
+
+/* USB Legacy Support Capability - section 7.1.1 */
+/* Add this offset, plus the value of xECP in HCCPARAMS to the base address */
+#define XHCI_LEGACY_SUPPORT_OFFSET	(0x00)
+
+/* USB Legacy Support Control and Status Register  - section 7.1.2 */
+/* Add this offset, plus the value of xECP in HCCPARAMS to the base address */
+#define XHCI_LEGACY_CONTROL_OFFSET	(0x04)
+/* bits 1:2, 5:12, and 17:19 need to be preserved; bits 21:28 should be zero */
+#define	XHCI_LEGACY_DISABLE_SMI		((0x3 << 1) + (0xff << 5) + (0x7 << 17))
+
+/* USB 2.0 xHCI 0.96 L1C capability - section 7.2.2.1.3.2 */
+#define XHCI_L1C               (1 << 16)
+
+/* USB 2.0 xHCI 1.0 hardware LMP capability - section 7.2.2.1.3.2 */
+#define XHCI_HLC               (1 << 19)
+
+/* command register values to disable interrupts and halt the HC */
+/* start/stop HC execution - do not write unless HC is halted*/
+#define XHCI_CMD_RUN		(1 << 0)
+/* Event Interrupt Enable - get irq when EINT bit is set in USBSTS register */
+#define XHCI_CMD_EIE		(1 << 2)
+/* Host System Error Interrupt Enable - get irq when HSEIE bit set in USBSTS */
+#define XHCI_CMD_HSEIE		(1 << 3)
+/* Enable Wrap Event - '1' means xHC generates an event when MFINDEX wraps. */
+#define XHCI_CMD_EWE		(1 << 10)
+
+#define XHCI_IRQS		(XHCI_CMD_EIE | XHCI_CMD_HSEIE | XHCI_CMD_EWE)
+
+/* true: Controller Not Ready to accept doorbell or op reg writes after reset */
+#define XHCI_STS_CNR		(1 << 11)
+
+struct xhci_ctrl {
+	struct xhci_hccr *hccr;	/* R/O registers, not need for volatile */
+	struct xhci_hcor *hcor;
+	struct xhci_doorbell_array *dba;
+	struct xhci_run_regs *run_regs;
+	struct xhci_device_context_array *dcbaa		\
+			__attribute__ ((aligned(ARCH_DMA_MINALIGN)));
+	struct xhci_ring *event_ring;
+	struct xhci_ring *cmd_ring;
+	struct xhci_ring *transfer_ring;
+	struct xhci_segment *seg;
+	struct xhci_intr_reg *ir_set;
+	struct xhci_erst erst;
+	struct xhci_erst_entry entry[ERST_NUM_SEGS];
+	struct xhci_virt_device *devs[MAX_HC_SLOTS];
+	int rootdev;
+};
+
+unsigned long trb_addr(struct xhci_segment *seg, union xhci_trb *trb);
+struct xhci_input_control_ctx
+		*xhci_get_input_control_ctx(struct xhci_container_ctx *ctx);
+struct xhci_slot_ctx *xhci_get_slot_ctx(struct xhci_ctrl *ctrl,
+					struct xhci_container_ctx *ctx);
+struct xhci_ep_ctx *xhci_get_ep_ctx(struct xhci_ctrl *ctrl,
+				    struct xhci_container_ctx *ctx,
+				    unsigned int ep_index);
+void xhci_endpoint_copy(struct xhci_ctrl *ctrl,
+			struct xhci_container_ctx *in_ctx,
+			struct xhci_container_ctx *out_ctx,
+			unsigned int ep_index);
+void xhci_slot_copy(struct xhci_ctrl *ctrl,
+		    struct xhci_container_ctx *in_ctx,
+		    struct xhci_container_ctx *out_ctx);
+void xhci_setup_addressable_virt_dev(struct usb_device *udev);
+void xhci_queue_command(struct xhci_ctrl *ctrl, u8 *ptr,
+			u32 slot_id, u32 ep_index, trb_type cmd);
+void xhci_acknowledge_event(struct xhci_ctrl *ctrl);
+union xhci_trb *xhci_wait_for_event(struct xhci_ctrl *ctrl, trb_type expected);
+int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
+		 int length, void *buffer);
+int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
+		 struct devrequest *req, int length, void *buffer);
+int xhci_check_maxpacket(struct usb_device *udev);
+void xhci_flush_cache(uint32_t addr, u32 type_len);
+void xhci_inval_cache(uint32_t addr, u32 type_len);
+void xhci_cleanup(struct xhci_ctrl *ctrl);
+struct xhci_ring *xhci_ring_alloc(unsigned int num_segs, bool link_trbs);
+int xhci_alloc_virt_device(struct usb_device *udev);
+int xhci_mem_init(struct xhci_ctrl *ctrl, struct xhci_hccr *hccr,
+		  struct xhci_hcor *hcor);
+
+#endif /* HOST_XHCI_H_ */