xhci: Initial xHCI implementation

Based on the implementation from Hector Martin <hector@marcansoft.com>

Hectors's implementation completely sidestepped the qemu usb system and
used libusb directly for usb device pass through.  So I've ripped out
the libusb bits (or left them in disabled, as reference for further
coding) and hooked up the qemu subsystem instead.  That work is not
complete yet though, partly due to limitations of the qemu usb
subsystem.  Nevertheless I think it is better to continue development
in-tree, especially as the qemu usb bits need a bunch of improvements
too for decent usb 3.0 support.

Current state:
  - usb-storage emulation should work ok.
  - Devices which need constant polling (HID emulation like usb-tablet)
    are known to not work.
  - ISO xfers are not implemented yet.
  - superspeed ports are not implemented yet.
  - usb pass-through is completely untested so far.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

4 files changed, 2754 insertions, 0 deletions

diff --git a/Makefile.objs b/Makefile.objs
index 8956cb974e..f94c881667 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -211,6 +211,7 @@ hw-obj-$(CONFIG_PCKBD) += pckbd.o
 hw-obj-$(CONFIG_USB_UHCI) += usb-uhci.o
 hw-obj-$(CONFIG_USB_OHCI) += usb-ohci.o
 hw-obj-$(CONFIG_USB_EHCI) += usb-ehci.o
+hw-obj-$(CONFIG_USB_XHCI) += usb-xhci.o
 hw-obj-$(CONFIG_FDC) += fdc.o
 hw-obj-$(CONFIG_ACPI) += acpi.o acpi_piix4.o
 hw-obj-$(CONFIG_APM) += pm_smbus.o apm.o
diff --git a/default-configs/pci.mak b/default-configs/pci.mak
index 22bd3502d4..9d3e1dbda1 100644
--- a/default-configs/pci.mak
+++ b/default-configs/pci.mak
@@ -4,6 +4,7 @@ CONFIG_VIRTIO=y
 CONFIG_USB_UHCI=y
 CONFIG_USB_OHCI=y
 CONFIG_USB_EHCI=y
+CONFIG_USB_XHCI=y
 CONFIG_NE2000_PCI=y
 CONFIG_EEPRO100_PCI=y
 CONFIG_PCNET_PCI=y
diff --git a/hw/pci_ids.h b/hw/pci_ids.h
index 83f38934ec..85e5372006 100644
--- a/hw/pci_ids.h
+++ b/hw/pci_ids.h
@@ -120,3 +120,6 @@
 
 #define PCI_VENDOR_ID_XEN               0x5853
 #define PCI_DEVICE_ID_XEN_PLATFORM      0x0001
+
+#define PCI_VENDOR_ID_NEC                0x1033
+#define PCI_DEVICE_ID_NEC_UPD720200      0x0194
diff --git a/hw/usb-xhci.c b/hw/usb-xhci.c
new file mode 100644
index 0000000000..28fe9de2a0
--- /dev/null
+++ b/hw/usb-xhci.c
@@ -0,0 +1,2749 @@
+/*
+ * USB xHCI controller emulation
+ *
+ * Copyright (c) 2011 Securiforest
+ * Date: 2011-05-11 ;  Author: Hector Martin <hector@marcansoft.com>
+ * Based on usb-ohci.c, emulates Renesas NEC USB 3.0
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+#include "hw.h"
+#include "qemu-timer.h"
+#include "usb.h"
+#include "pci.h"
+#include "qdev-addr.h"
+#include "msi.h"
+
+//#define DEBUG_XHCI
+//#define DEBUG_DATA
+
+#ifdef DEBUG_XHCI
+#define DPRINTF(...) fprintf(stderr, __VA_ARGS__)
+#else
+#define DPRINTF(...) do {} while (0)
+#endif
+#define FIXME() do { fprintf(stderr, "FIXME %s:%d\n", \
+                             __func__, __LINE__); abort(); } while (0)
+
+#define MAXSLOTS 8
+#define MAXINTRS 1
+
+#define USB2_PORTS 4
+#define USB3_PORTS 4
+
+#define MAXPORTS (USB2_PORTS+USB3_PORTS)
+
+#define TD_QUEUE 24
+#define BG_XFERS 8
+#define BG_PKTS 8
+
+/* Very pessimistic, let's hope it's enough for all cases */
+#define EV_QUEUE (((3*TD_QUEUE)+16)*MAXSLOTS)
+/* Do not deliver ER Full events. NEC's driver does some things not bound
+ * to the specs when it gets them */
+#define ER_FULL_HACK
+
+#define LEN_CAP         0x40
+#define OFF_OPER        LEN_CAP
+#define LEN_OPER        (0x400 + 0x10 * MAXPORTS)
+#define OFF_RUNTIME     ((OFF_OPER + LEN_OPER + 0x20) & ~0x1f)
+#define LEN_RUNTIME     (0x20 + MAXINTRS * 0x20)
+#define OFF_DOORBELL    (OFF_RUNTIME + LEN_RUNTIME)
+#define LEN_DOORBELL    ((MAXSLOTS + 1) * 0x20)
+
+/* must be power of 2 */
+#define LEN_REGS        0x2000
+
+#if (OFF_DOORBELL + LEN_DOORBELL) > LEN_REGS
+# error Increase LEN_REGS
+#endif
+
+#if MAXINTRS > 1
+# error TODO: only one interrupter supported
+#endif
+
+/* bit definitions */
+#define USBCMD_RS       (1<<0)
+#define USBCMD_HCRST    (1<<1)
+#define USBCMD_INTE     (1<<2)
+#define USBCMD_HSEE     (1<<3)
+#define USBCMD_LHCRST   (1<<7)
+#define USBCMD_CSS      (1<<8)
+#define USBCMD_CRS      (1<<9)
+#define USBCMD_EWE      (1<<10)
+#define USBCMD_EU3S     (1<<11)
+
+#define USBSTS_HCH      (1<<0)
+#define USBSTS_HSE      (1<<2)
+#define USBSTS_EINT     (1<<3)
+#define USBSTS_PCD      (1<<4)
+#define USBSTS_SSS      (1<<8)
+#define USBSTS_RSS      (1<<9)
+#define USBSTS_SRE      (1<<10)
+#define USBSTS_CNR      (1<<11)
+#define USBSTS_HCE      (1<<12)
+
+
+#define PORTSC_CCS          (1<<0)
+#define PORTSC_PED          (1<<1)
+#define PORTSC_OCA          (1<<3)
+#define PORTSC_PR           (1<<4)
+#define PORTSC_PLS_SHIFT        5
+#define PORTSC_PLS_MASK     0xf
+#define PORTSC_PP           (1<<9)
+#define PORTSC_SPEED_SHIFT      10
+#define PORTSC_SPEED_MASK   0xf
+#define PORTSC_SPEED_FULL   (1<<10)
+#define PORTSC_SPEED_LOW    (2<<10)
+#define PORTSC_SPEED_HIGH   (3<<10)
+#define PORTSC_SPEED_SUPER  (4<<10)
+#define PORTSC_PIC_SHIFT        14
+#define PORTSC_PIC_MASK     0x3
+#define PORTSC_LWS          (1<<16)
+#define PORTSC_CSC          (1<<17)
+#define PORTSC_PEC          (1<<18)
+#define PORTSC_WRC          (1<<19)
+#define PORTSC_OCC          (1<<20)
+#define PORTSC_PRC          (1<<21)
+#define PORTSC_PLC          (1<<22)
+#define PORTSC_CEC          (1<<23)
+#define PORTSC_CAS          (1<<24)
+#define PORTSC_WCE          (1<<25)
+#define PORTSC_WDE          (1<<26)
+#define PORTSC_WOE          (1<<27)
+#define PORTSC_DR           (1<<30)
+#define PORTSC_WPR          (1<<31)
+
+#define CRCR_RCS        (1<<0)
+#define CRCR_CS         (1<<1)
+#define CRCR_CA         (1<<2)
+#define CRCR_CRR        (1<<3)
+
+#define IMAN_IP         (1<<0)
+#define IMAN_IE         (1<<1)
+
+#define ERDP_EHB        (1<<3)
+
+#define TRB_SIZE 16
+typedef struct XHCITRB {
+    uint64_t parameter;
+    uint32_t status;
+    uint32_t control;
+    target_phys_addr_t addr;
+    bool ccs;
+} XHCITRB;
+
+
+typedef enum TRBType {
+    TRB_RESERVED = 0,
+    TR_NORMAL,
+    TR_SETUP,
+    TR_DATA,
+    TR_STATUS,
+    TR_ISOCH,
+    TR_LINK,
+    TR_EVDATA,
+    TR_NOOP,
+    CR_ENABLE_SLOT,
+    CR_DISABLE_SLOT,
+    CR_ADDRESS_DEVICE,
+    CR_CONFIGURE_ENDPOINT,
+    CR_EVALUATE_CONTEXT,
+    CR_RESET_ENDPOINT,
+    CR_STOP_ENDPOINT,
+    CR_SET_TR_DEQUEUE,
+    CR_RESET_DEVICE,
+    CR_FORCE_EVENT,
+    CR_NEGOTIATE_BW,
+    CR_SET_LATENCY_TOLERANCE,
+    CR_GET_PORT_BANDWIDTH,
+    CR_FORCE_HEADER,
+    CR_NOOP,
+    ER_TRANSFER = 32,
+    ER_COMMAND_COMPLETE,
+    ER_PORT_STATUS_CHANGE,
+    ER_BANDWIDTH_REQUEST,
+    ER_DOORBELL,
+    ER_HOST_CONTROLLER,
+    ER_DEVICE_NOTIFICATION,
+    ER_MFINDEX_WRAP,
+    /* vendor specific bits */
+    CR_VENDOR_VIA_CHALLENGE_RESPONSE = 48,
+    CR_VENDOR_NEC_FIRMWARE_REVISION  = 49,
+    CR_VENDOR_NEC_CHALLENGE_RESPONSE = 50,
+} TRBType;
+
+#define CR_LINK TR_LINK
+
+typedef enum TRBCCode {
+    CC_INVALID = 0,
+    CC_SUCCESS,
+    CC_DATA_BUFFER_ERROR,
+    CC_BABBLE_DETECTED,
+    CC_USB_TRANSACTION_ERROR,
+    CC_TRB_ERROR,
+    CC_STALL_ERROR,
+    CC_RESOURCE_ERROR,
+    CC_BANDWIDTH_ERROR,
+    CC_NO_SLOTS_ERROR,
+    CC_INVALID_STREAM_TYPE_ERROR,
+    CC_SLOT_NOT_ENABLED_ERROR,
+    CC_EP_NOT_ENABLED_ERROR,
+    CC_SHORT_PACKET,
+    CC_RING_UNDERRUN,
+    CC_RING_OVERRUN,
+    CC_VF_ER_FULL,
+    CC_PARAMETER_ERROR,
+    CC_BANDWIDTH_OVERRUN,
+    CC_CONTEXT_STATE_ERROR,
+    CC_NO_PING_RESPONSE_ERROR,
+    CC_EVENT_RING_FULL_ERROR,
+    CC_INCOMPATIBLE_DEVICE_ERROR,
+    CC_MISSED_SERVICE_ERROR,
+    CC_COMMAND_RING_STOPPED,
+    CC_COMMAND_ABORTED,
+    CC_STOPPED,
+    CC_STOPPED_LENGTH_INVALID,
+    CC_MAX_EXIT_LATENCY_TOO_LARGE_ERROR = 29,
+    CC_ISOCH_BUFFER_OVERRUN = 31,
+    CC_EVENT_LOST_ERROR,
+    CC_UNDEFINED_ERROR,
+    CC_INVALID_STREAM_ID_ERROR,
+    CC_SECONDARY_BANDWIDTH_ERROR,
+    CC_SPLIT_TRANSACTION_ERROR
+} TRBCCode;
+
+#define TRB_C               (1<<0)
+#define TRB_TYPE_SHIFT          10
+#define TRB_TYPE_MASK       0x3f
+#define TRB_TYPE(t)         (((t).control >> TRB_TYPE_SHIFT) & TRB_TYPE_MASK)
+
+#define TRB_EV_ED           (1<<2)
+
+#define TRB_TR_ENT          (1<<1)
+#define TRB_TR_ISP          (1<<2)
+#define TRB_TR_NS           (1<<3)
+#define TRB_TR_CH           (1<<4)
+#define TRB_TR_IOC          (1<<5)
+#define TRB_TR_IDT          (1<<6)
+#define TRB_TR_TBC_SHIFT        7
+#define TRB_TR_TBC_MASK     0x3
+#define TRB_TR_BEI          (1<<9)
+#define TRB_TR_TLBPC_SHIFT      16
+#define TRB_TR_TLBPC_MASK   0xf
+#define TRB_TR_FRAMEID_SHIFT    20
+#define TRB_TR_FRAMEID_MASK 0x7ff
+#define TRB_TR_SIA          (1<<31)
+
+#define TRB_TR_DIR          (1<<16)
+
+#define TRB_CR_SLOTID_SHIFT     24
+#define TRB_CR_SLOTID_MASK  0xff
+#define TRB_CR_EPID_SHIFT       16
+#define TRB_CR_EPID_MASK    0x1f
+
+#define TRB_CR_BSR          (1<<9)
+#define TRB_CR_DC           (1<<9)
+
+#define TRB_LK_TC           (1<<1)
+
+#define EP_TYPE_MASK        0x7
+#define EP_TYPE_SHIFT           3
+
+#define EP_STATE_MASK       0x7
+#define EP_DISABLED         (0<<0)
+#define EP_RUNNING          (1<<0)
+#define EP_HALTED           (2<<0)
+#define EP_STOPPED          (3<<0)
+#define EP_ERROR            (4<<0)
+
+#define SLOT_STATE_MASK     0x1f
+#define SLOT_STATE_SHIFT        27
+#define SLOT_STATE(s)       (((s)>>SLOT_STATE_SHIFT)&SLOT_STATE_MASK)
+#define SLOT_ENABLED        0
+#define SLOT_DEFAULT        1
+#define SLOT_ADDRESSED      2
+#define SLOT_CONFIGURED     3
+
+#define SLOT_CONTEXT_ENTRIES_MASK 0x1f
+#define SLOT_CONTEXT_ENTRIES_SHIFT 27
+
+typedef enum EPType {
+    ET_INVALID = 0,
+    ET_ISO_OUT,
+    ET_BULK_OUT,
+    ET_INTR_OUT,
+    ET_CONTROL,
+    ET_ISO_IN,
+    ET_BULK_IN,
+    ET_INTR_IN,
+} EPType;
+
+typedef struct XHCIRing {
+    target_phys_addr_t base;
+    target_phys_addr_t dequeue;
+    bool ccs;
+} XHCIRing;
+
+typedef struct XHCIPort {
+    USBPort port;
+    uint32_t portsc;
+} XHCIPort;
+
+struct XHCIState;
+typedef struct XHCIState XHCIState;
+
+typedef struct XHCITransfer {
+    XHCIState *xhci;
+    USBPacket packet;
+    bool running;
+    bool cancelled;
+    bool complete;
+    bool backgrounded;
+    unsigned int iso_pkts;
+    unsigned int slotid;
+    unsigned int epid;
+    bool in_xfer;
+    bool iso_xfer;
+    bool bg_xfer;
+
+    unsigned int trb_count;
+    unsigned int trb_alloced;
+    XHCITRB *trbs;
+
+    unsigned int data_length;
+    unsigned int data_alloced;
+    uint8_t *data;
+
+    TRBCCode status;
+
+    unsigned int pkts;
+    unsigned int pktsize;
+    unsigned int cur_pkt;
+} XHCITransfer;
+
+typedef struct XHCIEPContext {
+    XHCIRing ring;
+    unsigned int next_xfer;
+    unsigned int comp_xfer;
+    XHCITransfer transfers[TD_QUEUE];
+    bool bg_running;
+    bool bg_updating;
+    unsigned int next_bg;
+    XHCITransfer bg_transfers[BG_XFERS];
+    EPType type;
+    target_phys_addr_t pctx;
+    unsigned int max_psize;
+    bool has_bg;
+    uint32_t state;
+} XHCIEPContext;
+
+typedef struct XHCISlot {
+    bool enabled;
+    target_phys_addr_t ctx;
+    unsigned int port;
+    unsigned int devaddr;
+    XHCIEPContext * eps[31];
+} XHCISlot;
+
+typedef struct XHCIEvent {
+    TRBType type;
+    TRBCCode ccode;
+    uint64_t ptr;
+    uint32_t length;
+    uint32_t flags;
+    uint8_t slotid;
+    uint8_t epid;
+} XHCIEvent;
+
+struct XHCIState {
+    PCIDevice pci_dev;
+    USBBus bus;
+    qemu_irq irq;
+    MemoryRegion mem;
+    const char *name;
+    uint32_t msi;
+    unsigned int devaddr;
+
+    /* Operational Registers */
+    uint32_t usbcmd;
+    uint32_t usbsts;
+    uint32_t dnctrl;
+    uint32_t crcr_low;
+    uint32_t crcr_high;
+    uint32_t dcbaap_low;
+    uint32_t dcbaap_high;
+    uint32_t config;
+
+    XHCIPort ports[MAXPORTS];
+    XHCISlot slots[MAXSLOTS];
+
+    /* Runtime Registers */
+    uint32_t mfindex;
+    /* note: we only support one interrupter */
+    uint32_t iman;
+    uint32_t imod;
+    uint32_t erstsz;
+    uint32_t erstba_low;
+    uint32_t erstba_high;
+    uint32_t erdp_low;
+    uint32_t erdp_high;
+
+    target_phys_addr_t er_start;
+    uint32_t er_size;
+    bool er_pcs;
+    unsigned int er_ep_idx;
+    bool er_full;
+
+    XHCIEvent ev_buffer[EV_QUEUE];
+    unsigned int ev_buffer_put;
+    unsigned int ev_buffer_get;
+
+    XHCIRing cmd_ring;
+};
+
+typedef struct XHCIEvRingSeg {
+    uint32_t addr_low;
+    uint32_t addr_high;
+    uint32_t size;
+    uint32_t rsvd;
+} XHCIEvRingSeg;
+
+static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid,
+                         unsigned int epid);
+
+static inline target_phys_addr_t xhci_addr64(uint32_t low, uint32_t high)
+{
+#if TARGET_PHYS_ADDR_BITS > 32
+    return low | ((target_phys_addr_t)high << 32);
+#else
+    return low;
+#endif
+}
+
+static inline target_phys_addr_t xhci_mask64(uint64_t addr)
+{
+#if TARGET_PHYS_ADDR_BITS > 32
+    return addr;
+#else
+    return addr & 0xffffffff;
+#endif
+}
+
+static void xhci_irq_update(XHCIState *xhci)
+{
+    int level = 0;
+
+    if (xhci->iman & IMAN_IP && xhci->iman & IMAN_IE &&
+        xhci->usbcmd && USBCMD_INTE) {
+        level = 1;
+    }
+
+    DPRINTF("xhci_irq_update(): %d\n", level);
+
+    if (xhci->msi && msi_enabled(&xhci->pci_dev)) {
+        if (level) {
+            DPRINTF("xhci_irq_update(): MSI signal\n");
+            msi_notify(&xhci->pci_dev, 0);
+        }
+    } else {
+        qemu_set_irq(xhci->irq, level);
+    }
+}
+
+static inline int xhci_running(XHCIState *xhci)
+{
+    return !(xhci->usbsts & USBSTS_HCH) && !xhci->er_full;
+}
+
+static void xhci_die(XHCIState *xhci)
+{
+    xhci->usbsts |= USBSTS_HCE;
+    fprintf(stderr, "xhci: asserted controller error\n");
+}
+
+static void xhci_write_event(XHCIState *xhci, XHCIEvent *event)
+{
+    XHCITRB ev_trb;
+    target_phys_addr_t addr;
+
+    ev_trb.parameter = cpu_to_le64(event->ptr);
+    ev_trb.status = cpu_to_le32(event->length | (event->ccode << 24));
+    ev_trb.control = (event->slotid << 24) | (event->epid << 16) |
+                     event->flags | (event->type << TRB_TYPE_SHIFT);
+    if (xhci->er_pcs) {
+        ev_trb.control |= TRB_C;
+    }
+    ev_trb.control = cpu_to_le32(ev_trb.control);
+
+    DPRINTF("xhci_write_event(): [%d] %016"PRIx64" %08x %08x\n",
+            xhci->er_ep_idx, ev_trb.parameter, ev_trb.status, ev_trb.control);
+
+    addr = xhci->er_start + TRB_SIZE*xhci->er_ep_idx;
+    cpu_physical_memory_write(addr, (uint8_t *) &ev_trb, TRB_SIZE);
+
+    xhci->er_ep_idx++;
+    if (xhci->er_ep_idx >= xhci->er_size) {
+        xhci->er_ep_idx = 0;
+        xhci->er_pcs = !xhci->er_pcs;
+    }
+}
+
+static void xhci_events_update(XHCIState *xhci)
+{
+    target_phys_addr_t erdp;
+    unsigned int dp_idx;
+    bool do_irq = 0;
+
+    if (xhci->usbsts & USBSTS_HCH) {
+        return;
+    }
+
+    erdp = xhci_addr64(xhci->erdp_low, xhci->erdp_high);
+    if (erdp < xhci->er_start ||
+        erdp >= (xhci->er_start + TRB_SIZE*xhci->er_size)) {
+        fprintf(stderr, "xhci: ERDP out of bounds: "TARGET_FMT_plx"\n", erdp);
+        fprintf(stderr, "xhci: ER at "TARGET_FMT_plx" len %d\n",
+                xhci->er_start, xhci->er_size);
+        xhci_die(xhci);
+        return;
+    }
+    dp_idx = (erdp - xhci->er_start) / TRB_SIZE;
+    assert(dp_idx < xhci->er_size);
+
+    /* NEC didn't read section 4.9.4 of the spec (v1.0 p139 top Note) and thus
+     * deadlocks when the ER is full. Hack it by holding off events until
+     * the driver decides to free at least half of the ring */
+    if (xhci->er_full) {
+        int er_free = dp_idx - xhci->er_ep_idx;
+        if (er_free <= 0) {
+            er_free += xhci->er_size;
+        }
+        if (er_free < (xhci->er_size/2)) {
+            DPRINTF("xhci_events_update(): event ring still "
+                    "more than half full (hack)\n");
+            return;
+        }
+    }
+
+    while (xhci->ev_buffer_put != xhci->ev_buffer_get) {
+        assert(xhci->er_full);
+        if (((xhci->er_ep_idx+1) % xhci->er_size) == dp_idx) {
+            DPRINTF("xhci_events_update(): event ring full again\n");
+#ifndef ER_FULL_HACK
+            XHCIEvent full = {ER_HOST_CONTROLLER, CC_EVENT_RING_FULL_ERROR};
+            xhci_write_event(xhci, &full);
+#endif
+            do_irq = 1;
+            break;
+        }
+        XHCIEvent *event = &xhci->ev_buffer[xhci->ev_buffer_get];
+        xhci_write_event(xhci, event);
+        xhci->ev_buffer_get++;
+        do_irq = 1;
+        if (xhci->ev_buffer_get == EV_QUEUE) {
+            xhci->ev_buffer_get = 0;
+        }
+    }
+
+    if (do_irq) {
+        xhci->erdp_low |= ERDP_EHB;
+        xhci->iman |= IMAN_IP;
+        xhci->usbsts |= USBSTS_EINT;
+        xhci_irq_update(xhci);
+    }
+
+    if (xhci->er_full && xhci->ev_buffer_put == xhci->ev_buffer_get) {
+        DPRINTF("xhci_events_update(): event ring no longer full\n");
+        xhci->er_full = 0;
+    }
+    return;
+}
+
+static void xhci_event(XHCIState *xhci, XHCIEvent *event)
+{
+    target_phys_addr_t erdp;
+    unsigned int dp_idx;
+
+    if (xhci->er_full) {
+        DPRINTF("xhci_event(): ER full, queueing\n");
+        if (((xhci->ev_buffer_put+1) % EV_QUEUE) == xhci->ev_buffer_get) {
+            fprintf(stderr, "xhci: event queue full, dropping event!\n");
+            return;
+        }
+        xhci->ev_buffer[xhci->ev_buffer_put++] = *event;
+        if (xhci->ev_buffer_put == EV_QUEUE) {
+            xhci->ev_buffer_put = 0;
+        }
+        return;
+    }
+
+    erdp = xhci_addr64(xhci->erdp_low, xhci->erdp_high);
+    if (erdp < xhci->er_start ||
+        erdp >= (xhci->er_start + TRB_SIZE*xhci->er_size)) {
+        fprintf(stderr, "xhci: ERDP out of bounds: "TARGET_FMT_plx"\n", erdp);
+        fprintf(stderr, "xhci: ER at "TARGET_FMT_plx" len %d\n",
+                xhci->er_start, xhci->er_size);
+        xhci_die(xhci);
+        return;
+    }
+
+    dp_idx = (erdp - xhci->er_start) / TRB_SIZE;
+    assert(dp_idx < xhci->er_size);
+
+    if ((xhci->er_ep_idx+1) % xhci->er_size == dp_idx) {
+        DPRINTF("xhci_event(): ER full, queueing\n");
+#ifndef ER_FULL_HACK
+        XHCIEvent full = {ER_HOST_CONTROLLER, CC_EVENT_RING_FULL_ERROR};
+        xhci_write_event(xhci, &full);
+#endif
+        xhci->er_full = 1;
+        if (((xhci->ev_buffer_put+1) % EV_QUEUE) == xhci->ev_buffer_get) {
+            fprintf(stderr, "xhci: event queue full, dropping event!\n");
+            return;
+        }
+        xhci->ev_buffer[xhci->ev_buffer_put++] = *event;
+        if (xhci->ev_buffer_put == EV_QUEUE) {
+            xhci->ev_buffer_put = 0;
+        }
+    } else {
+        xhci_write_event(xhci, event);
+    }
+
+    xhci->erdp_low |= ERDP_EHB;
+    xhci->iman |= IMAN_IP;
+    xhci->usbsts |= USBSTS_EINT;
+
+    xhci_irq_update(xhci);
+}
+
+static void xhci_ring_init(XHCIState *xhci, XHCIRing *ring,
+                           target_phys_addr_t base)
+{
+    ring->base = base;
+    ring->dequeue = base;
+    ring->ccs = 1;
+}
+
+static TRBType xhci_ring_fetch(XHCIState *xhci, XHCIRing *ring, XHCITRB *trb,
+                               target_phys_addr_t *addr)
+{
+    while (1) {
+        TRBType type;
+        cpu_physical_memory_read(ring->dequeue, (uint8_t *) trb, TRB_SIZE);
+        trb->addr = ring->dequeue;
+        trb->ccs = ring->ccs;
+        le64_to_cpus(&trb->parameter);
+        le32_to_cpus(&trb->status);
+        le32_to_cpus(&trb->control);
+
+        DPRINTF("xhci: TRB fetched [" TARGET_FMT_plx "]: "
+                "%016" PRIx64 " %08x %08x\n",
+                ring->dequeue, trb->parameter, trb->status, trb->control);
+
+        if ((trb->control & TRB_C) != ring->ccs) {
+            return 0;
+        }
+
+        type = TRB_TYPE(*trb);
+
+        if (type != TR_LINK) {
+            if (addr) {
+                *addr = ring->dequeue;
+            }
+            ring->dequeue += TRB_SIZE;
+            return type;
+        } else {
+            ring->dequeue = xhci_mask64(trb->parameter);
+            if (trb->control & TRB_LK_TC) {
+                ring->ccs = !ring->ccs;
+            }
+        }
+    }
+}
+
+static int xhci_ring_chain_length(XHCIState *xhci, const XHCIRing *ring)
+{
+    XHCITRB trb;
+    int length = 0;
+    target_phys_addr_t dequeue = ring->dequeue;
+    bool ccs = ring->ccs;
+    /* hack to bundle together the two/three TDs that make a setup transfer */
+    bool control_td_set = 0;
+
+    while (1) {
+        TRBType type;
+        cpu_physical_memory_read(dequeue, (uint8_t *) &trb, TRB_SIZE);
+        le64_to_cpus(&trb.parameter);
+        le32_to_cpus(&trb.status);
+        le32_to_cpus(&trb.control);
+
+        DPRINTF("xhci: TRB peeked [" TARGET_FMT_plx "]: "
+                "%016" PRIx64 " %08x %08x\n",
+                dequeue, trb.parameter, trb.status, trb.control);
+
+        if ((trb.control & TRB_C) != ccs) {
+            return -length;
+        }
+
+        type = TRB_TYPE(trb);
+
+        if (type == TR_LINK) {
+            dequeue = xhci_mask64(trb.parameter);
+            if (trb.control & TRB_LK_TC) {
+                ccs = !ccs;
+            }
+            continue;
+        }
+
+        length += 1;
+        dequeue += TRB_SIZE;
+
+        if (type == TR_SETUP) {
+            control_td_set = 1;
+        } else if (type == TR_STATUS) {
+            control_td_set = 0;
+        }
+
+        if (!control_td_set && !(trb.control & TRB_TR_CH)) {
+            return length;
+        }
+    }
+}
+
+static void xhci_er_reset(XHCIState *xhci)
+{
+    XHCIEvRingSeg seg;
+
+    /* cache the (sole) event ring segment location */
+    if (xhci->erstsz != 1) {
+        fprintf(stderr, "xhci: invalid value for ERSTSZ: %d\n", xhci->erstsz);
+        xhci_die(xhci);
+        return;
+    }
+    target_phys_addr_t erstba = xhci_addr64(xhci->erstba_low, xhci->erstba_high);
+    cpu_physical_memory_read(erstba, (uint8_t *) &seg, sizeof(seg));
+    le32_to_cpus(&seg.addr_low);
+    le32_to_cpus(&seg.addr_high);
+    le32_to_cpus(&seg.size);
+    if (seg.size < 16 || seg.size > 4096) {
+        fprintf(stderr, "xhci: invalid value for segment size: %d\n", seg.size);
+        xhci_die(xhci);
+        return;
+    }
+    xhci->er_start = xhci_addr64(seg.addr_low, seg.addr_high);
+    xhci->er_size = seg.size;
+
+    xhci->er_ep_idx = 0;
+    xhci->er_pcs = 1;
+    xhci->er_full = 0;
+
+    DPRINTF("xhci: event ring:" TARGET_FMT_plx " [%d]\n",
+            xhci->er_start, xhci->er_size);
+}
+
+static void xhci_run(XHCIState *xhci)
+{
+    DPRINTF("xhci_run()\n");
+
+    xhci->usbsts &= ~USBSTS_HCH;
+}
+
+static void xhci_stop(XHCIState *xhci)
+{
+    DPRINTF("xhci_stop()\n");
+    xhci->usbsts |= USBSTS_HCH;
+    xhci->crcr_low &= ~CRCR_CRR;
+}
+
+static void xhci_set_ep_state(XHCIState *xhci, XHCIEPContext *epctx,
+                              uint32_t state)
+{
+    uint32_t ctx[5];
+    if (epctx->state == state) {
+        return;
+    }
+
+    cpu_physical_memory_read(epctx->pctx, (uint8_t *) ctx, sizeof(ctx));
+    ctx[0] &= ~EP_STATE_MASK;
+    ctx[0] |= state;
+    ctx[2] = epctx->ring.dequeue | epctx->ring.ccs;
+    ctx[3] = (epctx->ring.dequeue >> 16) >> 16;
+    DPRINTF("xhci: set epctx: " TARGET_FMT_plx " state=%d dequeue=%08x%08x\n",
+            epctx->pctx, state, ctx[3], ctx[2]);
+    cpu_physical_memory_write(epctx->pctx, (uint8_t *) ctx, sizeof(ctx));
+    epctx->state = state;
+}
+
+static TRBCCode xhci_enable_ep(XHCIState *xhci, unsigned int slotid,
+                               unsigned int epid, target_phys_addr_t pctx,
+                               uint32_t *ctx)
+{
+    XHCISlot *slot;
+    XHCIEPContext *epctx;
+    target_phys_addr_t dequeue;
+    int i;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    assert(epid >= 1 && epid <= 31);
+
+    DPRINTF("xhci_enable_ep(%d, %d)\n", slotid, epid);
+
+    slot = &xhci->slots[slotid-1];
+    if (slot->eps[epid-1]) {
+        fprintf(stderr, "xhci: slot %d ep %d already enabled!\n", slotid, epid);
+        return CC_TRB_ERROR;
+    }
+
+    epctx = g_malloc(sizeof(XHCIEPContext));
+    memset(epctx, 0, sizeof(XHCIEPContext));
+
+    slot->eps[epid-1] = epctx;
+
+    dequeue = xhci_addr64(ctx[2] & ~0xf, ctx[3]);
+    xhci_ring_init(xhci, &epctx->ring, dequeue);
+    epctx->ring.ccs = ctx[2] & 1;
+
+    epctx->type = (ctx[1] >> EP_TYPE_SHIFT) & EP_TYPE_MASK;
+    DPRINTF("xhci: endpoint %d.%d type is %d\n", epid/2, epid%2, epctx->type);
+    epctx->pctx = pctx;
+    epctx->max_psize = ctx[1]>>16;
+    epctx->max_psize *= 1+((ctx[1]>>8)&0xff);
+    epctx->has_bg = false;
+    if (epctx->type == ET_ISO_IN) {
+        epctx->has_bg = true;
+    }
+    DPRINTF("xhci: endpoint %d.%d max transaction (burst) size is %d\n",
+            epid/2, epid%2, epctx->max_psize);
+    for (i = 0; i < ARRAY_SIZE(epctx->transfers); i++) {
+        usb_packet_init(&epctx->transfers[i].packet);
+    }
+
+    epctx->state = EP_RUNNING;
+    ctx[0] &= ~EP_STATE_MASK;
+    ctx[0] |= EP_RUNNING;
+
+    return CC_SUCCESS;
+}
+
+static int xhci_ep_nuke_xfers(XHCIState *xhci, unsigned int slotid,
+                               unsigned int epid)
+{
+    XHCISlot *slot;
+    XHCIEPContext *epctx;
+    int i, xferi, killed = 0;
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    assert(epid >= 1 && epid <= 31);
+
+    DPRINTF("xhci_ep_nuke_xfers(%d, %d)\n", slotid, epid);
+
+    slot = &xhci->slots[slotid-1];
+
+    if (!slot->eps[epid-1]) {
+        return 0;
+    }
+
+    epctx = slot->eps[epid-1];
+
+    xferi = epctx->next_xfer;
+    for (i = 0; i < TD_QUEUE; i++) {
+        XHCITransfer *t = &epctx->transfers[xferi];
+        if (t->running) {
+            t->cancelled = 1;
+            /* libusb_cancel_transfer(t->usbxfer) */
+            DPRINTF("xhci: cancelling transfer %d, waiting for it to complete...\n", i);
+            killed++;
+        }
+        if (t->backgrounded) {
+            t->backgrounded = 0;
+        }
+        if (t->trbs) {
+            g_free(t->trbs);
+        }
+        if (t->data) {
+            g_free(t->data);
+        }
+
+        t->trbs = NULL;
+        t->data = NULL;
+        t->trb_count = t->trb_alloced = 0;
+        t->data_length = t->data_alloced = 0;
+        xferi = (xferi + 1) % TD_QUEUE;
+    }
+    if (epctx->has_bg) {
+        xferi = epctx->next_bg;
+        for (i = 0; i < BG_XFERS; i++) {
+            XHCITransfer *t = &epctx->bg_transfers[xferi];
+            if (t->running) {
+                t->cancelled = 1;
+                /* libusb_cancel_transfer(t->usbxfer); */
+                DPRINTF("xhci: cancelling bg transfer %d, waiting for it to complete...\n", i);
+                killed++;
+            }
+            if (t->data) {
+                g_free(t->data);
+            }
+
+            t->data = NULL;
+            xferi = (xferi + 1) % BG_XFERS;
+        }
+    }
+    return killed;
+}
+
+static TRBCCode xhci_disable_ep(XHCIState *xhci, unsigned int slotid,
+                               unsigned int epid)
+{
+    XHCISlot *slot;
+    XHCIEPContext *epctx;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    assert(epid >= 1 && epid <= 31);
+
+    DPRINTF("xhci_disable_ep(%d, %d)\n", slotid, epid);
+
+    slot = &xhci->slots[slotid-1];
+
+    if (!slot->eps[epid-1]) {
+        DPRINTF("xhci: slot %d ep %d already disabled\n", slotid, epid);
+        return CC_SUCCESS;
+    }
+
+    xhci_ep_nuke_xfers(xhci, slotid, epid);
+
+    epctx = slot->eps[epid-1];
+
+    xhci_set_ep_state(xhci, epctx, EP_DISABLED);
+
+    g_free(epctx);
+    slot->eps[epid-1] = NULL;
+
+    return CC_SUCCESS;
+}
+
+static TRBCCode xhci_stop_ep(XHCIState *xhci, unsigned int slotid,
+                             unsigned int epid)
+{
+    XHCISlot *slot;
+    XHCIEPContext *epctx;
+
+    DPRINTF("xhci_stop_ep(%d, %d)\n", slotid, epid);
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+
+    if (epid < 1 || epid > 31) {
+        fprintf(stderr, "xhci: bad ep %d\n", epid);
+        return CC_TRB_ERROR;
+    }
+
+    slot = &xhci->slots[slotid-1];
+
+    if (!slot->eps[epid-1]) {
+        DPRINTF("xhci: slot %d ep %d not enabled\n", slotid, epid);
+        return CC_EP_NOT_ENABLED_ERROR;
+    }
+
+    if (xhci_ep_nuke_xfers(xhci, slotid, epid) > 0) {
+        fprintf(stderr, "xhci: FIXME: endpoint stopped w/ xfers running, "
+                "data might be lost\n");
+    }
+
+    epctx = slot->eps[epid-1];
+
+    xhci_set_ep_state(xhci, epctx, EP_STOPPED);
+
+    return CC_SUCCESS;
+}
+
+static TRBCCode xhci_reset_ep(XHCIState *xhci, unsigned int slotid,
+                              unsigned int epid)
+{
+    XHCISlot *slot;
+    XHCIEPContext *epctx;
+    USBDevice *dev;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+
+    DPRINTF("xhci_reset_ep(%d, %d)\n", slotid, epid);
+
+    if (epid < 1 || epid > 31) {
+        fprintf(stderr, "xhci: bad ep %d\n", epid);
+        return CC_TRB_ERROR;
+    }
+
+    slot = &xhci->slots[slotid-1];
+
+    if (!slot->eps[epid-1]) {
+        DPRINTF("xhci: slot %d ep %d not enabled\n", slotid, epid);
+        return CC_EP_NOT_ENABLED_ERROR;
+    }
+
+    epctx = slot->eps[epid-1];
+
+    if (epctx->state != EP_HALTED) {
+        fprintf(stderr, "xhci: reset EP while EP %d not halted (%d)\n",
+                epid, epctx->state);
+        return CC_CONTEXT_STATE_ERROR;
+    }
+
+    if (xhci_ep_nuke_xfers(xhci, slotid, epid) > 0) {
+        fprintf(stderr, "xhci: FIXME: endpoint reset w/ xfers running, "
+                "data might be lost\n");
+    }
+
+    uint8_t ep = epid>>1;
+
+    if (epid & 1) {
+        ep |= 0x80;
+    }
+
+    dev = xhci->ports[xhci->slots[slotid-1].port-1].port.dev;
+    if (!dev) {
+        return CC_USB_TRANSACTION_ERROR;
+    }
+
+    xhci_set_ep_state(xhci, epctx, EP_STOPPED);
+
+    return CC_SUCCESS;
+}
+
+static TRBCCode xhci_set_ep_dequeue(XHCIState *xhci, unsigned int slotid,
+                                    unsigned int epid, uint64_t pdequeue)
+{
+    XHCISlot *slot;
+    XHCIEPContext *epctx;
+    target_phys_addr_t dequeue;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+
+    if (epid < 1 || epid > 31) {
+        fprintf(stderr, "xhci: bad ep %d\n", epid);
+        return CC_TRB_ERROR;
+    }
+
+    DPRINTF("xhci_set_ep_dequeue(%d, %d, %016"PRIx64")\n", slotid, epid, pdequeue);
+    dequeue = xhci_mask64(pdequeue);
+
+    slot = &xhci->slots[slotid-1];
+
+    if (!slot->eps[epid-1]) {
+        DPRINTF("xhci: slot %d ep %d not enabled\n", slotid, epid);
+        return CC_EP_NOT_ENABLED_ERROR;
+    }
+
+    epctx = slot->eps[epid-1];
+
+
+    if (epctx->state != EP_STOPPED) {
+        fprintf(stderr, "xhci: set EP dequeue pointer while EP %d not stopped\n", epid);
+        return CC_CONTEXT_STATE_ERROR;
+    }
+
+    xhci_ring_init(xhci, &epctx->ring, dequeue & ~0xF);
+    epctx->ring.ccs = dequeue & 1;
+
+    xhci_set_ep_state(xhci, epctx, EP_STOPPED);
+
+    return CC_SUCCESS;
+}
+
+static int xhci_xfer_data(XHCITransfer *xfer, uint8_t *data,
+                          unsigned int length, bool in_xfer, bool out_xfer,
+                          bool report)
+{
+    int i;
+    uint32_t edtla = 0;
+    unsigned int transferred = 0;
+    unsigned int left = length;
+    bool reported = 0;
+    bool shortpkt = 0;
+    XHCIEvent event = {ER_TRANSFER, CC_SUCCESS};
+    XHCIState *xhci = xfer->xhci;
+
+    DPRINTF("xhci_xfer_data(len=%d, in_xfer=%d, out_xfer=%d, report=%d)\n",
+            length, in_xfer, out_xfer, report);
+
+    assert(!(in_xfer && out_xfer));
+
+    for (i = 0; i < xfer->trb_count; i++) {
+        XHCITRB *trb = &xfer->trbs[i];
+        target_phys_addr_t addr;
+        unsigned int chunk = 0;
+
+        switch (TRB_TYPE(*trb)) {
+        case TR_DATA:
+            if ((!(trb->control & TRB_TR_DIR)) != (!in_xfer)) {
+                fprintf(stderr, "xhci: data direction mismatch for TR_DATA\n");
+                xhci_die(xhci);
+                return transferred;
+            }
+            /* fallthrough */
+        case TR_NORMAL:
+        case TR_ISOCH:
+            addr = xhci_mask64(trb->parameter);
+            chunk = trb->status & 0x1ffff;
+            if (chunk > left) {
+                chunk = left;
+                shortpkt = 1;
+            }
+            if (in_xfer || out_xfer) {
+                if (trb->control & TRB_TR_IDT) {
+                    uint64_t idata;
+                    if (chunk > 8 || in_xfer) {
+                        fprintf(stderr, "xhci: invalid immediate data TRB\n");
+                        xhci_die(xhci);
+                        return transferred;
+                    }
+                    idata = le64_to_cpu(trb->parameter);
+                    memcpy(data, &idata, chunk);
+                } else {
+                    DPRINTF("xhci_xfer_data: r/w(%d) %d bytes at "
+                            TARGET_FMT_plx "\n", in_xfer, chunk, addr);
+                    if (in_xfer) {
+                        cpu_physical_memory_write(addr, data, chunk);
+                    } else {
+                        cpu_physical_memory_read(addr, data, chunk);
+                    }
+#ifdef DEBUG_DATA
+                    unsigned int count = chunk;
+                    int i;
+                    if (count > 16) {
+                        count = 16;
+                    }
+                    DPRINTF(" ::");
+                    for (i = 0; i < count; i++) {
+                        DPRINTF(" %02x", data[i]);
+                    }
+                    DPRINTF("\n");
+#endif
+                }
+            }
+            left -= chunk;
+            data += chunk;
+            edtla += chunk;
+            transferred += chunk;
+            break;
+        case TR_STATUS:
+            reported = 0;
+            shortpkt = 0;
+            break;
+        }
+
+        if (report && !reported && (trb->control & TRB_TR_IOC ||
+            (shortpkt && (trb->control & TRB_TR_ISP)))) {
+            event.slotid = xfer->slotid;
+            event.epid = xfer->epid;
+            event.length = (trb->status & 0x1ffff) - chunk;
+            event.flags = 0;
+            event.ptr = trb->addr;
+            if (xfer->status == CC_SUCCESS) {
+                event.ccode = shortpkt ? CC_SHORT_PACKET : CC_SUCCESS;
+            } else {
+                event.ccode = xfer->status;
+            }
+            if (TRB_TYPE(*trb) == TR_EVDATA) {
+                event.ptr = trb->parameter;
+                event.flags |= TRB_EV_ED;
+                event.length = edtla & 0xffffff;
+                DPRINTF("xhci_xfer_data: EDTLA=%d\n", event.length);
+                edtla = 0;
+            }
+            xhci_event(xhci, &event);
+            reported = 1;
+        }
+    }
+    return transferred;
+}
+
+static void xhci_stall_ep(XHCITransfer *xfer)
+{
+    XHCIState *xhci = xfer->xhci;
+    XHCISlot *slot = &xhci->slots[xfer->slotid-1];
+    XHCIEPContext *epctx = slot->eps[xfer->epid-1];
+
+    epctx->ring.dequeue = xfer->trbs[0].addr;
+    epctx->ring.ccs = xfer->trbs[0].ccs;
+    xhci_set_ep_state(xhci, epctx, EP_HALTED);
+    DPRINTF("xhci: stalled slot %d ep %d\n", xfer->slotid, xfer->epid);
+    DPRINTF("xhci: will continue at "TARGET_FMT_plx"\n", epctx->ring.dequeue);
+}
+
+static int xhci_submit(XHCIState *xhci, XHCITransfer *xfer,
+                       XHCIEPContext *epctx);
+
+static void xhci_bg_update(XHCIState *xhci, XHCIEPContext *epctx)
+{
+    if (epctx->bg_updating) {
+        return;
+    }
+    DPRINTF("xhci_bg_update(%p, %p)\n", xhci, epctx);
+    assert(epctx->has_bg);
+    DPRINTF("xhci: fg=%d bg=%d\n", epctx->comp_xfer, epctx->next_bg);
+    epctx->bg_updating = 1;
+    while (epctx->transfers[epctx->comp_xfer].backgrounded &&
+           epctx->bg_transfers[epctx->next_bg].complete) {
+        XHCITransfer *fg = &epctx->transfers[epctx->comp_xfer];
+        XHCITransfer *bg = &epctx->bg_transfers[epctx->next_bg];
+#if 0
+        DPRINTF("xhci: completing fg %d from bg %d.%d (stat: %d)\n",
+                epctx->comp_xfer, epctx->next_bg, bg->cur_pkt,
+                bg->usbxfer->iso_packet_desc[bg->cur_pkt].status
+               );
+#endif
+        assert(epctx->type == ET_ISO_IN);
+        assert(bg->iso_xfer);
+        assert(bg->in_xfer);
+        uint8_t *p = bg->data + bg->cur_pkt * bg->pktsize;
+#if 0
+        int len = bg->usbxfer->iso_packet_desc[bg->cur_pkt].actual_length;
+        fg->status = libusb_to_ccode(bg->usbxfer->iso_packet_desc[bg->cur_pkt].status);
+#else
+        int len = 0;
+        FIXME();
+#endif
+        fg->complete = 1;
+        fg->backgrounded = 0;
+
+        if (fg->status == CC_STALL_ERROR) {
+            xhci_stall_ep(fg);
+        }
+
+        xhci_xfer_data(fg, p, len, 1, 0, 1);
+
+        epctx->comp_xfer++;
+        if (epctx->comp_xfer == TD_QUEUE) {
+            epctx->comp_xfer = 0;
+        }
+        DPRINTF("next fg xfer: %d\n", epctx->comp_xfer);
+        bg->cur_pkt++;
+        if (bg->cur_pkt == bg->pkts) {
+            bg->complete = 0;
+            if (xhci_submit(xhci, bg, epctx) < 0) {
+                fprintf(stderr, "xhci: bg resubmit failed\n");
+            }
+            epctx->next_bg++;
+            if (epctx->next_bg == BG_XFERS) {
+                epctx->next_bg = 0;
+            }
+            DPRINTF("next bg xfer: %d\n", epctx->next_bg);
+
+        xhci_kick_ep(xhci, fg->slotid, fg->epid);
+        }
+    }
+    epctx->bg_updating = 0;
+}
+
+#if 0
+static void xhci_xfer_cb(struct libusb_transfer *transfer)
+{
+    XHCIState *xhci;
+    XHCITransfer *xfer;
+
+    xfer = (XHCITransfer *)transfer->user_data;
+    xhci = xfer->xhci;
+
+    DPRINTF("xhci_xfer_cb(slot=%d, ep=%d, status=%d)\n", xfer->slotid,
+            xfer->epid, transfer->status);
+
+    assert(xfer->slotid >= 1 && xfer->slotid <= MAXSLOTS);
+    assert(xfer->epid >= 1 && xfer->epid <= 31);
+
+    if (xfer->cancelled) {
+        DPRINTF("xhci: transfer cancelled, not reporting anything\n");
+        xfer->running = 0;
+        return;
+    }
+
+    XHCIEPContext *epctx;
+    XHCISlot *slot;
+    slot = &xhci->slots[xfer->slotid-1];
+    assert(slot->eps[xfer->epid-1]);
+    epctx = slot->eps[xfer->epid-1];
+
+    if (xfer->bg_xfer) {
+        DPRINTF("xhci: background transfer, updating\n");
+        xfer->complete = 1;
+        xfer->running = 0;
+        xhci_bg_update(xhci, epctx);
+        return;
+    }
+
+    if (xfer->iso_xfer) {
+        transfer->status = transfer->iso_packet_desc[0].status;
+        transfer->actual_length = transfer->iso_packet_desc[0].actual_length;
+    }
+
+    xfer->status = libusb_to_ccode(transfer->status);
+
+    xfer->complete = 1;
+    xfer->running = 0;
+
+    if (transfer->status == LIBUSB_TRANSFER_STALL)
+        xhci_stall_ep(xhci, epctx, xfer);
+
+    DPRINTF("xhci: transfer actual length = %d\n", transfer->actual_length);
+
+    if (xfer->in_xfer) {
+        if (xfer->epid == 1) {
+            xhci_xfer_data(xhci, xfer, xfer->data + 8,
+                           transfer->actual_length, 1, 0, 1);
+        } else {
+            xhci_xfer_data(xhci, xfer, xfer->data,
+                           transfer->actual_length, 1, 0, 1);
+        }
+    } else {
+        xhci_xfer_data(xhci, xfer, NULL, transfer->actual_length, 0, 0, 1);
+    }
+
+    xhci_kick_ep(xhci, xfer->slotid, xfer->epid);
+}
+
+static int xhci_hle_control(XHCIState *xhci, XHCITransfer *xfer,
+                            uint8_t bmRequestType, uint8_t bRequest,
+                            uint16_t wValue, uint16_t wIndex, uint16_t wLength)
+{
+    uint16_t type_req = (bmRequestType << 8) | bRequest;
+
+    switch (type_req) {
+        case 0x0000 | USB_REQ_SET_CONFIGURATION:
+            DPRINTF("xhci: HLE switch configuration\n");
+            return xhci_switch_config(xhci, xfer->slotid, wValue) == 0;
+        case 0x0100 | USB_REQ_SET_INTERFACE:
+            DPRINTF("xhci: HLE set interface altsetting\n");
+            return xhci_set_iface_alt(xhci, xfer->slotid, wIndex, wValue) == 0;
+        case 0x0200 | USB_REQ_CLEAR_FEATURE:
+            if (wValue == 0) { // endpoint halt
+                DPRINTF("xhci: HLE clear halt\n");
+                return xhci_clear_halt(xhci, xfer->slotid, wIndex);
+            }
+        case 0x0000 | USB_REQ_SET_ADDRESS:
+            fprintf(stderr, "xhci: warn: illegal SET_ADDRESS request\n");
+            return 0;
+        default:
+            return 0;
+    }
+}
+#endif
+
+static int xhci_setup_packet(XHCITransfer *xfer, XHCIPort *port, int ep)
+{
+    usb_packet_setup(&xfer->packet,
+                     xfer->in_xfer ? USB_TOKEN_IN : USB_TOKEN_OUT,
+                     xfer->xhci->slots[xfer->slotid-1].devaddr,
+                     ep & 0x7f);
+    usb_packet_addbuf(&xfer->packet, xfer->data, xfer->data_length);
+    DPRINTF("xhci: setup packet pid 0x%x addr %d ep %d\n",
+            xfer->packet.pid, xfer->packet.devaddr, xfer->packet.devep);
+    return 0;
+}
+
+static int xhci_complete_packet(XHCITransfer *xfer, int ret)
+{
+    if (ret == USB_RET_ASYNC) {
+        xfer->running = 1;
+        xfer->complete = 0;
+        xfer->cancelled = 0;
+        return 0;
+    } else {
+        xfer->running = 0;
+        xfer->complete = 1;
+    }
+
+    if (ret >= 0) {
+        xfer->status = CC_SUCCESS;
+        xhci_xfer_data(xfer, xfer->data, ret, xfer->in_xfer, 0, 1);
+        return 0;
+    }
+
+    /* error */
+    switch (ret) {
+    case USB_RET_NODEV:
+        xfer->status = CC_USB_TRANSACTION_ERROR;
+        xhci_xfer_data(xfer, xfer->data, 0, xfer->in_xfer, 0, 1);
+        xhci_stall_ep(xfer);
+        break;
+    case USB_RET_STALL:
+        xfer->status = CC_STALL_ERROR;
+        xhci_xfer_data(xfer, xfer->data, 0, xfer->in_xfer, 0, 1);
+        xhci_stall_ep(xfer);
+        break;
+    default:
+        fprintf(stderr, "%s: FIXME: ret = %d\n", __FUNCTION__, ret);
+        FIXME();
+    }
+    return 0;
+}
+
+static int xhci_fire_ctl_transfer(XHCIState *xhci, XHCITransfer *xfer)
+{
+    XHCITRB *trb_setup, *trb_status;
+    uint8_t bmRequestType, bRequest;
+    uint16_t wValue, wLength, wIndex;
+    XHCIPort *port;
+    USBDevice *dev;
+    int ret;
+
+    DPRINTF("xhci_fire_ctl_transfer(slot=%d)\n", xfer->slotid);
+
+    trb_setup = &xfer->trbs[0];
+    trb_status = &xfer->trbs[xfer->trb_count-1];
+
+    /* at most one Event Data TRB allowed after STATUS */
+    if (TRB_TYPE(*trb_status) == TR_EVDATA && xfer->trb_count > 2) {
+        trb_status--;
+    }
+
+    /* do some sanity checks */
+    if (TRB_TYPE(*trb_setup) != TR_SETUP) {
+        fprintf(stderr, "xhci: ep0 first TD not SETUP: %d\n",
+                TRB_TYPE(*trb_setup));
+        return -1;
+    }
+    if (TRB_TYPE(*trb_status) != TR_STATUS) {
+        fprintf(stderr, "xhci: ep0 last TD not STATUS: %d\n",
+                TRB_TYPE(*trb_status));
+        return -1;
+    }
+    if (!(trb_setup->control & TRB_TR_IDT)) {
+        fprintf(stderr, "xhci: Setup TRB doesn't have IDT set\n");
+        return -1;
+    }
+    if ((trb_setup->status & 0x1ffff) != 8) {
+        fprintf(stderr, "xhci: Setup TRB has bad length (%d)\n",
+                (trb_setup->status & 0x1ffff));
+        return -1;
+    }
+
+    bmRequestType = trb_setup->parameter;
+    bRequest = trb_setup->parameter >> 8;
+    wValue = trb_setup->parameter >> 16;
+    wIndex = trb_setup->parameter >> 32;
+    wLength = trb_setup->parameter >> 48;
+
+    if (xfer->data && xfer->data_alloced < wLength) {
+        xfer->data_alloced = 0;
+        g_free(xfer->data);
+        xfer->data = NULL;
+    }
+    if (!xfer->data) {
+        DPRINTF("xhci: alloc %d bytes data\n", wLength);
+        xfer->data = g_malloc(wLength+1);
+        xfer->data_alloced = wLength;
+    }
+    xfer->data_length = wLength;
+
+    port = &xhci->ports[xhci->slots[xfer->slotid-1].port-1];
+    dev = port->port.dev;
+    if (!dev) {
+        fprintf(stderr, "xhci: slot %d port %d has no device\n", xfer->slotid,
+                xhci->slots[xfer->slotid-1].port);
+        return -1;
+    }
+
+    xfer->in_xfer = bmRequestType & USB_DIR_IN;
+    xfer->iso_xfer = false;
+
+    xhci_setup_packet(xfer, port, 0);
+    if (!xfer->in_xfer) {
+        xhci_xfer_data(xfer, xfer->data, wLength, 0, 1, 0);
+    }
+    ret = dev->info->handle_control(dev, &xfer->packet,
+                                    (bmRequestType << 8) | bRequest,
+                                    wValue, wIndex, wLength, xfer->data);
+
+    xhci_complete_packet(xfer, ret);
+    if (!xfer->running) {
+        xhci_kick_ep(xhci, xfer->slotid, xfer->epid);
+    }
+    return 0;
+}
+
+static int xhci_submit(XHCIState *xhci, XHCITransfer *xfer, XHCIEPContext *epctx)
+{
+    XHCIPort *port;
+    USBDevice *dev;
+    int ret;
+
+    DPRINTF("xhci_submit(slotid=%d,epid=%d)\n", xfer->slotid, xfer->epid);
+    uint8_t ep = xfer->epid>>1;
+
+    xfer->in_xfer = epctx->type>>2;
+    if (xfer->in_xfer) {
+        ep |= 0x80;
+    }
+
+    if (xfer->data && xfer->data_alloced < xfer->data_length) {
+        xfer->data_alloced = 0;
+        g_free(xfer->data);
+        xfer->data = NULL;
+    }
+    if (!xfer->data && xfer->data_length) {
+        DPRINTF("xhci: alloc %d bytes data\n", xfer->data_length);
+        xfer->data = g_malloc(xfer->data_length);
+        xfer->data_alloced = xfer->data_length;
+    }
+    if (epctx->type == ET_ISO_IN || epctx->type == ET_ISO_OUT) {
+        if (!xfer->bg_xfer) {
+            xfer->pkts = 1;
+        }
+    } else {
+        xfer->pkts = 0;
+    }
+
+    port = &xhci->ports[xhci->slots[xfer->slotid-1].port-1];
+    dev = port->port.dev;
+    if (!dev) {
+        fprintf(stderr, "xhci: slot %d port %d has no device\n", xfer->slotid,
+                xhci->slots[xfer->slotid-1].port);
+        return -1;
+    }
+
+    xhci_setup_packet(xfer, port, ep);
+
+    switch(epctx->type) {
+    case ET_INTR_OUT:
+    case ET_INTR_IN:
+    case ET_BULK_OUT:
+    case ET_BULK_IN:
+        break;
+    case ET_ISO_OUT:
+    case ET_ISO_IN:
+        FIXME();
+        break;
+    default:
+        fprintf(stderr, "xhci: unknown or unhandled EP type %d (ep %02x)\n",
+                epctx->type, ep);
+        return -1;
+    }
+
+    if (!xfer->in_xfer) {
+        xhci_xfer_data(xfer, xfer->data, xfer->data_length, 0, 1, 0);
+    }
+    ret = usb_handle_packet(dev, &xfer->packet);
+
+    xhci_complete_packet(xfer, ret);
+    if (!xfer->running) {
+        xhci_kick_ep(xhci, xfer->slotid, xfer->epid);
+    }
+    return 0;
+}
+
+static int xhci_fire_transfer(XHCIState *xhci, XHCITransfer *xfer, XHCIEPContext *epctx)
+{
+    int i;
+    unsigned int length = 0;
+    XHCITRB *trb;
+
+    DPRINTF("xhci_fire_transfer(slotid=%d,epid=%d)\n", xfer->slotid, xfer->epid);
+
+    for (i = 0; i < xfer->trb_count; i++) {
+        trb = &xfer->trbs[i];
+        if (TRB_TYPE(*trb) == TR_NORMAL || TRB_TYPE(*trb) == TR_ISOCH) {
+            length += trb->status & 0x1ffff;
+        }
+    }
+    DPRINTF("xhci: total TD length=%d\n", length);
+
+    if (!epctx->has_bg) {
+        xfer->data_length = length;
+        xfer->backgrounded = 0;
+        return xhci_submit(xhci, xfer, epctx);
+    } else {
+        if (!epctx->bg_running) {
+            for (i = 0; i < BG_XFERS; i++) {
+                XHCITransfer *t = &epctx->bg_transfers[i];
+                t->xhci = xhci;
+                t->epid = xfer->epid;
+                t->slotid = xfer->slotid;
+                t->pkts = BG_PKTS;
+                t->pktsize = epctx->max_psize;
+                t->data_length = t->pkts * t->pktsize;
+                t->bg_xfer = 1;
+                if (xhci_submit(xhci, t, epctx) < 0) {
+                    fprintf(stderr, "xhci: bg submit failed\n");
+                    return -1;
+                }
+            }
+            epctx->bg_running = 1;
+        }
+        xfer->backgrounded = 1;
+        xhci_bg_update(xhci, epctx);
+        return 0;
+    }
+}
+
+static void xhci_kick_ep(XHCIState *xhci, unsigned int slotid, unsigned int epid)
+{
+    XHCIEPContext *epctx;
+    int length;
+    int i;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    assert(epid >= 1 && epid <= 31);
+    DPRINTF("xhci_kick_ep(%d, %d)\n", slotid, epid);
+
+    if (!xhci->slots[slotid-1].enabled) {
+        fprintf(stderr, "xhci: xhci_kick_ep for disabled slot %d\n", slotid);
+        return;
+    }
+    epctx = xhci->slots[slotid-1].eps[epid-1];
+    if (!epctx) {
+        fprintf(stderr, "xhci: xhci_kick_ep for disabled endpoint %d,%d\n",
+                epid, slotid);
+        return;
+    }
+
+    if (epctx->state == EP_HALTED) {
+        DPRINTF("xhci: ep halted, not running schedule\n");
+        return;
+    }
+
+    xhci_set_ep_state(xhci, epctx, EP_RUNNING);
+
+    while (1) {
+        XHCITransfer *xfer = &epctx->transfers[epctx->next_xfer];
+        if (xfer->running || xfer->backgrounded) {
+            DPRINTF("xhci: ep is busy\n");
+            break;
+        }
+        length = xhci_ring_chain_length(xhci, &epctx->ring);
+        if (length < 0) {
+            DPRINTF("xhci: incomplete TD (%d TRBs)\n", -length);
+            break;
+        } else if (length == 0) {
+            break;
+        }
+        DPRINTF("xhci: fetching %d-TRB TD\n", length);
+        if (xfer->trbs && xfer->trb_alloced < length) {
+            xfer->trb_count = 0;
+            xfer->trb_alloced = 0;
+            g_free(xfer->trbs);
+            xfer->trbs = NULL;
+        }
+        if (!xfer->trbs) {
+            xfer->trbs = g_malloc(sizeof(XHCITRB) * length);
+            xfer->trb_alloced = length;
+        }
+        xfer->trb_count = length;
+
+        for (i = 0; i < length; i++) {
+            assert(xhci_ring_fetch(xhci, &epctx->ring, &xfer->trbs[i], NULL));
+        }
+        xfer->xhci = xhci;
+        xfer->epid = epid;
+        xfer->slotid = slotid;
+
+        if (epid == 1) {
+            if (xhci_fire_ctl_transfer(xhci, xfer) >= 0) {
+                epctx->next_xfer = (epctx->next_xfer + 1) % TD_QUEUE;
+            } else {
+                fprintf(stderr, "xhci: error firing CTL transfer\n");
+            }
+        } else {
+            if (xhci_fire_transfer(xhci, xfer, epctx) >= 0) {
+                epctx->next_xfer = (epctx->next_xfer + 1) % TD_QUEUE;
+            } else {
+                fprintf(stderr, "xhci: error firing data transfer\n");
+            }
+        }
+
+        /*
+         * Qemu usb can't handle multiple in-flight xfers.
+         * Also xfers might be finished here already,
+         * possibly with an error.  Stop here for now.
+         */
+        break;
+    }
+}
+
+static TRBCCode xhci_enable_slot(XHCIState *xhci, unsigned int slotid)
+{
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    DPRINTF("xhci_enable_slot(%d)\n", slotid);
+    xhci->slots[slotid-1].enabled = 1;
+    xhci->slots[slotid-1].port = 0;
+    memset(xhci->slots[slotid-1].eps, 0, sizeof(XHCIEPContext*)*31);
+
+    return CC_SUCCESS;
+}
+
+static TRBCCode xhci_disable_slot(XHCIState *xhci, unsigned int slotid)
+{
+    int i;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    DPRINTF("xhci_disable_slot(%d)\n", slotid);
+
+    for (i = 1; i <= 31; i++) {
+        if (xhci->slots[slotid-1].eps[i-1]) {
+            xhci_disable_ep(xhci, slotid, i);
+        }
+    }
+
+    xhci->slots[slotid-1].enabled = 0;
+    return CC_SUCCESS;
+}
+
+static TRBCCode xhci_address_slot(XHCIState *xhci, unsigned int slotid,
+                                  uint64_t pictx, bool bsr)
+{
+    XHCISlot *slot;
+    USBDevice *dev;
+    target_phys_addr_t ictx, octx, dcbaap;
+    uint64_t poctx;
+    uint32_t ictl_ctx[2];
+    uint32_t slot_ctx[4];
+    uint32_t ep0_ctx[5];
+    unsigned int port;
+    int i;
+    TRBCCode res;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    DPRINTF("xhci_address_slot(%d)\n", slotid);
+
+    dcbaap = xhci_addr64(xhci->dcbaap_low, xhci->dcbaap_high);
+    cpu_physical_memory_read(dcbaap + 8*slotid,
+                             (uint8_t *) &poctx, sizeof(poctx));
+    ictx = xhci_mask64(pictx);
+    octx = xhci_mask64(le64_to_cpu(poctx));
+
+    DPRINTF("xhci: input context at "TARGET_FMT_plx"\n", ictx);
+    DPRINTF("xhci: output context at "TARGET_FMT_plx"\n", octx);
+
+    cpu_physical_memory_read(ictx, (uint8_t *) ictl_ctx, sizeof(ictl_ctx));
+
+    if (ictl_ctx[0] != 0x0 || ictl_ctx[1] != 0x3) {
+        fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
+                ictl_ctx[0], ictl_ctx[1]);
+        return CC_TRB_ERROR;
+    }
+
+    cpu_physical_memory_read(ictx+32, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+    cpu_physical_memory_read(ictx+64, (uint8_t *) ep0_ctx, sizeof(ep0_ctx));
+
+    DPRINTF("xhci: input slot context: %08x %08x %08x %08x\n",
+            slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
+
+    DPRINTF("xhci: input ep0 context: %08x %08x %08x %08x %08x\n",
+            ep0_ctx[0], ep0_ctx[1], ep0_ctx[2], ep0_ctx[3], ep0_ctx[4]);
+
+    port = (slot_ctx[1]>>16) & 0xFF;
+    dev = xhci->ports[port-1].port.dev;
+
+    if (port < 1 || port > MAXPORTS) {
+        fprintf(stderr, "xhci: bad port %d\n", port);
+        return CC_TRB_ERROR;
+    } else if (!dev) {
+        fprintf(stderr, "xhci: port %d not connected\n", port);
+        return CC_USB_TRANSACTION_ERROR;
+    }
+
+    for (i = 0; i < MAXSLOTS; i++) {
+        if (xhci->slots[i].port == port) {
+            fprintf(stderr, "xhci: port %d already assigned to slot %d\n",
+                    port, i+1);
+            return CC_TRB_ERROR;
+        }
+    }
+
+    slot = &xhci->slots[slotid-1];
+    slot->port = port;
+    slot->ctx = octx;
+
+    if (bsr) {
+        slot_ctx[3] = SLOT_DEFAULT << SLOT_STATE_SHIFT;
+    } else {
+        slot->devaddr = xhci->devaddr++;
+        slot_ctx[3] = (SLOT_ADDRESSED << SLOT_STATE_SHIFT) | slot->devaddr;
+        DPRINTF("xhci: device address is %d\n", slot->devaddr);
+        dev->info->handle_control(dev, NULL,
+                                  DeviceOutRequest | USB_REQ_SET_ADDRESS,
+                                  slot->devaddr, 0, 0, NULL);
+    }
+
+    res = xhci_enable_ep(xhci, slotid, 1, octx+32, ep0_ctx);
+
+    DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
+            slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
+    DPRINTF("xhci: output ep0 context: %08x %08x %08x %08x %08x\n",
+            ep0_ctx[0], ep0_ctx[1], ep0_ctx[2], ep0_ctx[3], ep0_ctx[4]);
+
+    cpu_physical_memory_write(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+    cpu_physical_memory_write(octx+32, (uint8_t *) ep0_ctx, sizeof(ep0_ctx));
+
+    return res;
+}
+
+
+static TRBCCode xhci_configure_slot(XHCIState *xhci, unsigned int slotid,
+                                  uint64_t pictx, bool dc)
+{
+    target_phys_addr_t ictx, octx;
+    uint32_t ictl_ctx[2];
+    uint32_t slot_ctx[4];
+    uint32_t islot_ctx[4];
+    uint32_t ep_ctx[5];
+    int i;
+    TRBCCode res;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    DPRINTF("xhci_configure_slot(%d)\n", slotid);
+
+    ictx = xhci_mask64(pictx);
+    octx = xhci->slots[slotid-1].ctx;
+
+    DPRINTF("xhci: input context at "TARGET_FMT_plx"\n", ictx);
+    DPRINTF("xhci: output context at "TARGET_FMT_plx"\n", octx);
+
+    if (dc) {
+        for (i = 2; i <= 31; i++) {
+            if (xhci->slots[slotid-1].eps[i-1]) {
+                xhci_disable_ep(xhci, slotid, i);
+            }
+        }
+
+        cpu_physical_memory_read(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+        slot_ctx[3] &= ~(SLOT_STATE_MASK << SLOT_STATE_SHIFT);
+        slot_ctx[3] |= SLOT_ADDRESSED << SLOT_STATE_SHIFT;
+        DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
+                slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
+        cpu_physical_memory_write(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+
+        return CC_SUCCESS;
+    }
+
+    cpu_physical_memory_read(ictx, (uint8_t *) ictl_ctx, sizeof(ictl_ctx));
+
+    if ((ictl_ctx[0] & 0x3) != 0x0 || (ictl_ctx[1] & 0x3) != 0x1) {
+        fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
+                ictl_ctx[0], ictl_ctx[1]);
+        return CC_TRB_ERROR;
+    }
+
+    cpu_physical_memory_read(ictx+32, (uint8_t *) islot_ctx, sizeof(islot_ctx));
+    cpu_physical_memory_read(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+
+    if (SLOT_STATE(slot_ctx[3]) < SLOT_ADDRESSED) {
+        fprintf(stderr, "xhci: invalid slot state %08x\n", slot_ctx[3]);
+        return CC_CONTEXT_STATE_ERROR;
+    }
+
+    for (i = 2; i <= 31; i++) {
+        if (ictl_ctx[0] & (1<<i)) {
+            xhci_disable_ep(xhci, slotid, i);
+        }
+        if (ictl_ctx[1] & (1<<i)) {
+            cpu_physical_memory_read(ictx+32+(32*i),
+                                     (uint8_t *) ep_ctx, sizeof(ep_ctx));
+            DPRINTF("xhci: input ep%d.%d context: %08x %08x %08x %08x %08x\n",
+                    i/2, i%2, ep_ctx[0], ep_ctx[1], ep_ctx[2],
+                    ep_ctx[3], ep_ctx[4]);
+            xhci_disable_ep(xhci, slotid, i);
+            res = xhci_enable_ep(xhci, slotid, i, octx+(32*i), ep_ctx);
+            if (res != CC_SUCCESS) {
+                return res;
+            }
+            DPRINTF("xhci: output ep%d.%d context: %08x %08x %08x %08x %08x\n",
+                    i/2, i%2, ep_ctx[0], ep_ctx[1], ep_ctx[2],
+                    ep_ctx[3], ep_ctx[4]);
+            cpu_physical_memory_write(octx+(32*i),
+                                      (uint8_t *) ep_ctx, sizeof(ep_ctx));
+        }
+    }
+
+    slot_ctx[3] &= ~(SLOT_STATE_MASK << SLOT_STATE_SHIFT);
+    slot_ctx[3] |= SLOT_CONFIGURED << SLOT_STATE_SHIFT;
+    slot_ctx[0] &= ~(SLOT_CONTEXT_ENTRIES_MASK << SLOT_CONTEXT_ENTRIES_SHIFT);
+    slot_ctx[0] |= islot_ctx[0] & (SLOT_CONTEXT_ENTRIES_MASK <<
+                                   SLOT_CONTEXT_ENTRIES_SHIFT);
+    DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
+            slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
+
+    cpu_physical_memory_write(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+
+    return CC_SUCCESS;
+}
+
+
+static TRBCCode xhci_evaluate_slot(XHCIState *xhci, unsigned int slotid,
+                                   uint64_t pictx)
+{
+    target_phys_addr_t ictx, octx;
+    uint32_t ictl_ctx[2];
+    uint32_t iep0_ctx[5];
+    uint32_t ep0_ctx[5];
+    uint32_t islot_ctx[4];
+    uint32_t slot_ctx[4];
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    DPRINTF("xhci_evaluate_slot(%d)\n", slotid);
+
+    ictx = xhci_mask64(pictx);
+    octx = xhci->slots[slotid-1].ctx;
+
+    DPRINTF("xhci: input context at "TARGET_FMT_plx"\n", ictx);
+    DPRINTF("xhci: output context at "TARGET_FMT_plx"\n", octx);
+
+    cpu_physical_memory_read(ictx, (uint8_t *) ictl_ctx, sizeof(ictl_ctx));
+
+    if (ictl_ctx[0] != 0x0 || ictl_ctx[1] & ~0x3) {
+        fprintf(stderr, "xhci: invalid input context control %08x %08x\n",
+                ictl_ctx[0], ictl_ctx[1]);
+        return CC_TRB_ERROR;
+    }
+
+    if (ictl_ctx[1] & 0x1) {
+        cpu_physical_memory_read(ictx+32,
+                                 (uint8_t *) islot_ctx, sizeof(islot_ctx));
+
+        DPRINTF("xhci: input slot context: %08x %08x %08x %08x\n",
+                islot_ctx[0], islot_ctx[1], islot_ctx[2], islot_ctx[3]);
+
+        cpu_physical_memory_read(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+
+        slot_ctx[1] &= ~0xFFFF; /* max exit latency */
+        slot_ctx[1] |= islot_ctx[1] & 0xFFFF;
+        slot_ctx[2] &= ~0xFF00000; /* interrupter target */
+        slot_ctx[2] |= islot_ctx[2] & 0xFF000000;
+
+        DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
+                slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
+
+        cpu_physical_memory_write(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+    }
+
+    if (ictl_ctx[1] & 0x2) {
+        cpu_physical_memory_read(ictx+64,
+                                 (uint8_t *) iep0_ctx, sizeof(iep0_ctx));
+
+        DPRINTF("xhci: input ep0 context: %08x %08x %08x %08x %08x\n",
+                iep0_ctx[0], iep0_ctx[1], iep0_ctx[2],
+                iep0_ctx[3], iep0_ctx[4]);
+
+        cpu_physical_memory_read(octx+32, (uint8_t *) ep0_ctx, sizeof(ep0_ctx));
+
+        ep0_ctx[1] &= ~0xFFFF0000; /* max packet size*/
+        ep0_ctx[1] |= iep0_ctx[1] & 0xFFFF0000;
+
+        DPRINTF("xhci: output ep0 context: %08x %08x %08x %08x %08x\n",
+                ep0_ctx[0], ep0_ctx[1], ep0_ctx[2], ep0_ctx[3], ep0_ctx[4]);
+
+        cpu_physical_memory_write(octx+32,
+                                  (uint8_t *) ep0_ctx, sizeof(ep0_ctx));
+    }
+
+    return CC_SUCCESS;
+}
+
+static TRBCCode xhci_reset_slot(XHCIState *xhci, unsigned int slotid)
+{
+    uint32_t slot_ctx[4];
+    target_phys_addr_t octx;
+    int i;
+
+    assert(slotid >= 1 && slotid <= MAXSLOTS);
+    DPRINTF("xhci_reset_slot(%d)\n", slotid);
+
+    octx = xhci->slots[slotid-1].ctx;
+
+    DPRINTF("xhci: output context at "TARGET_FMT_plx"\n", octx);
+
+    for (i = 2; i <= 31; i++) {
+        if (xhci->slots[slotid-1].eps[i-1]) {
+            xhci_disable_ep(xhci, slotid, i);
+        }
+    }
+
+    cpu_physical_memory_read(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+    slot_ctx[3] &= ~(SLOT_STATE_MASK << SLOT_STATE_SHIFT);
+    slot_ctx[3] |= SLOT_DEFAULT << SLOT_STATE_SHIFT;
+    DPRINTF("xhci: output slot context: %08x %08x %08x %08x\n",
+            slot_ctx[0], slot_ctx[1], slot_ctx[2], slot_ctx[3]);
+    cpu_physical_memory_write(octx, (uint8_t *) slot_ctx, sizeof(slot_ctx));
+
+    return CC_SUCCESS;
+}
+
+static unsigned int xhci_get_slot(XHCIState *xhci, XHCIEvent *event, XHCITRB *trb)
+{
+    unsigned int slotid;
+    slotid = (trb->control >> TRB_CR_SLOTID_SHIFT) & TRB_CR_SLOTID_MASK;
+    if (slotid < 1 || slotid > MAXSLOTS) {
+        fprintf(stderr, "xhci: bad slot id %d\n", slotid);
+        event->ccode = CC_TRB_ERROR;
+        return 0;
+    } else if (!xhci->slots[slotid-1].enabled) {
+        fprintf(stderr, "xhci: slot id %d not enabled\n", slotid);
+        event->ccode = CC_SLOT_NOT_ENABLED_ERROR;
+        return 0;
+    }
+    return slotid;
+}
+
+static TRBCCode xhci_get_port_bandwidth(XHCIState *xhci, uint64_t pctx)
+{
+    target_phys_addr_t ctx;
+    uint8_t bw_ctx[MAXPORTS+1];
+
+    DPRINTF("xhci_get_port_bandwidth()\n");
+
+    ctx = xhci_mask64(pctx);
+
+    DPRINTF("xhci: bandwidth context at "TARGET_FMT_plx"\n", ctx);
+
+    /* TODO: actually implement real values here */
+    bw_ctx[0] = 0;
+    memset(&bw_ctx[1], 80, MAXPORTS); /* 80% */
+    cpu_physical_memory_write(ctx, bw_ctx, sizeof(bw_ctx));
+
+    return CC_SUCCESS;
+}
+
+static uint32_t rotl(uint32_t v, unsigned count)
+{
+    count &= 31;
+    return (v << count) | (v >> (32 - count));
+}
+
+
+static uint32_t xhci_nec_challenge(uint32_t hi, uint32_t lo)
+{
+    uint32_t val;
+    val = rotl(lo - 0x49434878, 32 - ((hi>>8) & 0x1F));
+    val += rotl(lo + 0x49434878, hi & 0x1F);
+    val -= rotl(hi ^ 0x49434878, (lo >> 16) & 0x1F);
+    return ~val;
+}
+
+static void xhci_via_challenge(uint64_t addr)
+{
+    uint32_t buf[8];
+    uint32_t obuf[8];
+    target_phys_addr_t paddr = xhci_mask64(addr);
+
+    cpu_physical_memory_read(paddr, (uint8_t *) &buf, 32);
+
+    memcpy(obuf, buf, sizeof(obuf));
+
+    if ((buf[0] & 0xff) == 2) {
+        obuf[0] = 0x49932000 + 0x54dc200 * buf[2] + 0x7429b578 * buf[3];
+        obuf[0] |=  (buf[2] * buf[3]) & 0xff;
+        obuf[1] = 0x0132bb37 + 0xe89 * buf[2] + 0xf09 * buf[3];
+        obuf[2] = 0x0066c2e9 + 0x2091 * buf[2] + 0x19bd * buf[3];
+        obuf[3] = 0xd5281342 + 0x2cc9691 * buf[2] + 0x2367662 * buf[3];
+        obuf[4] = 0x0123c75c + 0x1595 * buf[2] + 0x19ec * buf[3];
+        obuf[5] = 0x00f695de + 0x26fd * buf[2] + 0x3e9 * buf[3];
+        obuf[6] = obuf[2] ^ obuf[3] ^ 0x29472956;
+        obuf[7] = obuf[2] ^ obuf[3] ^ 0x65866593;
+    }
+
+    cpu_physical_memory_write(paddr, (uint8_t *) &obuf, 32);
+}
+
+static void xhci_process_commands(XHCIState *xhci)
+{
+    XHCITRB trb;
+    TRBType type;
+    XHCIEvent event = {ER_COMMAND_COMPLETE, CC_SUCCESS};
+    target_phys_addr_t addr;
+    unsigned int i, slotid = 0;
+
+    DPRINTF("xhci_process_commands()\n");
+    if (!xhci_running(xhci)) {
+        DPRINTF("xhci_process_commands() called while xHC stopped or paused\n");
+        return;
+    }
+
+    xhci->crcr_low |= CRCR_CRR;
+
+    while ((type = xhci_ring_fetch(xhci, &xhci->cmd_ring, &trb, &addr))) {
+        event.ptr = addr;
+        switch (type) {
+        case CR_ENABLE_SLOT:
+            for (i = 0; i < MAXSLOTS; i++) {
+                if (!xhci->slots[i].enabled) {
+                    break;
+                }
+            }
+            if (i >= MAXSLOTS) {
+                fprintf(stderr, "xhci: no device slots available\n");
+                event.ccode = CC_NO_SLOTS_ERROR;
+            } else {
+                slotid = i+1;
+                event.ccode = xhci_enable_slot(xhci, slotid);
+            }
+            break;
+        case CR_DISABLE_SLOT:
+            slotid = xhci_get_slot(xhci, &event, &trb);
+            if (slotid) {
+                event.ccode = xhci_disable_slot(xhci, slotid);
+            }
+            break;
+        case CR_ADDRESS_DEVICE:
+            slotid = xhci_get_slot(xhci, &event, &trb);
+            if (slotid) {
+                event.ccode = xhci_address_slot(xhci, slotid, trb.parameter,
+                                                trb.control & TRB_CR_BSR);
+            }
+            break;
+        case CR_CONFIGURE_ENDPOINT:
+            slotid = xhci_get_slot(xhci, &event, &trb);
+            if (slotid) {
+                event.ccode = xhci_configure_slot(xhci, slotid, trb.parameter,
+                                                  trb.control & TRB_CR_DC);
+            }
+            break;
+        case CR_EVALUATE_CONTEXT:
+            slotid = xhci_get_slot(xhci, &event, &trb);
+            if (slotid) {
+                event.ccode = xhci_evaluate_slot(xhci, slotid, trb.parameter);
+            }
+            break;
+        case CR_STOP_ENDPOINT:
+            slotid = xhci_get_slot(xhci, &event, &trb);
+            if (slotid) {
+                unsigned int epid = (trb.control >> TRB_CR_EPID_SHIFT)
+                    & TRB_CR_EPID_MASK;
+                event.ccode = xhci_stop_ep(xhci, slotid, epid);
+            }
+            break;
+        case CR_RESET_ENDPOINT:
+            slotid = xhci_get_slot(xhci, &event, &trb);
+            if (slotid) {
+                unsigned int epid = (trb.control >> TRB_CR_EPID_SHIFT)
+                    & TRB_CR_EPID_MASK;
+                event.ccode = xhci_reset_ep(xhci, slotid, epid);
+            }
+            break;
+        case CR_SET_TR_DEQUEUE:
+            slotid = xhci_get_slot(xhci, &event, &trb);
+            if (slotid) {
+                unsigned int epid = (trb.control >> TRB_CR_EPID_SHIFT)
+                    & TRB_CR_EPID_MASK;
+                event.ccode = xhci_set_ep_dequeue(xhci, slotid, epid,
+                                                  trb.parameter);
+            }
+            break;
+        case CR_RESET_DEVICE:
+            slotid = xhci_get_slot(xhci, &event, &trb);
+            if (slotid) {
+                event.ccode = xhci_reset_slot(xhci, slotid);
+            }
+            break;
+        case CR_GET_PORT_BANDWIDTH:
+            event.ccode = xhci_get_port_bandwidth(xhci, trb.parameter);
+            break;
+        case CR_VENDOR_VIA_CHALLENGE_RESPONSE:
+            xhci_via_challenge(trb.parameter);
+            break;
+        case CR_VENDOR_NEC_FIRMWARE_REVISION:
+            event.type = 48; /* NEC reply */
+            event.length = 0x3025;
+            break;
+        case CR_VENDOR_NEC_CHALLENGE_RESPONSE:
+        {
+            uint32_t chi = trb.parameter >> 32;
+            uint32_t clo = trb.parameter;
+            uint32_t val = xhci_nec_challenge(chi, clo);
+            event.length = val & 0xFFFF;
+            event.epid = val >> 16;
+            slotid = val >> 24;
+            event.type = 48; /* NEC reply */
+        }
+        break;
+        default:
+            fprintf(stderr, "xhci: unimplemented command %d\n", type);
+            event.ccode = CC_TRB_ERROR;
+            break;
+        }
+        event.slotid = slotid;
+        xhci_event(xhci, &event);
+    }
+}
+
+static void xhci_update_port(XHCIState *xhci, XHCIPort *port, int is_detach)
+{
+    int nr = port->port.index + 1;
+
+    port->portsc = PORTSC_PP;
+    if (port->port.dev && !is_detach) {
+        port->portsc |= PORTSC_CCS;
+        switch (port->port.dev->speed) {
+        case USB_SPEED_LOW:
+            port->portsc |= PORTSC_SPEED_LOW;
+            break;
+        case USB_SPEED_FULL:
+            port->portsc |= PORTSC_SPEED_FULL;
+            break;
+        case USB_SPEED_HIGH:
+            port->portsc |= PORTSC_SPEED_HIGH;
+            break;
+        }
+    }
+
+    if (xhci_running(xhci)) {
+        port->portsc |= PORTSC_CSC;
+        XHCIEvent ev = { ER_PORT_STATUS_CHANGE, CC_SUCCESS, nr << 24};
+        xhci_event(xhci, &ev);
+        DPRINTF("xhci: port change event for port %d\n", nr);
+    }
+}
+
+static void xhci_reset(void *opaque)
+{
+    XHCIState *xhci = opaque;
+    int i;
+
+    DPRINTF("xhci: full reset\n");
+    if (!(xhci->usbsts & USBSTS_HCH)) {
+        fprintf(stderr, "xhci: reset while running!\n");
+    }
+
+    xhci->usbcmd = 0;
+    xhci->usbsts = USBSTS_HCH;
+    xhci->dnctrl = 0;
+    xhci->crcr_low = 0;
+    xhci->crcr_high = 0;
+    xhci->dcbaap_low = 0;
+    xhci->dcbaap_high = 0;
+    xhci->config = 0;
+    xhci->devaddr = 2;
+
+    for (i = 0; i < MAXSLOTS; i++) {
+        xhci_disable_slot(xhci, i+1);
+    }
+
+    for (i = 0; i < MAXPORTS; i++) {
+        xhci_update_port(xhci, xhci->ports + i, 0);
+    }
+
+    xhci->mfindex = 0;
+    xhci->iman = 0;
+    xhci->imod = 0;
+    xhci->erstsz = 0;
+    xhci->erstba_low = 0;
+    xhci->erstba_high = 0;
+    xhci->erdp_low = 0;
+    xhci->erdp_high = 0;
+
+    xhci->er_ep_idx = 0;
+    xhci->er_pcs = 1;
+    xhci->er_full = 0;
+    xhci->ev_buffer_put = 0;
+    xhci->ev_buffer_get = 0;
+}
+
+static uint32_t xhci_cap_read(XHCIState *xhci, uint32_t reg)
+{
+    DPRINTF("xhci_cap_read(0x%x)\n", reg);
+
+    switch (reg) {
+    case 0x00: /* HCIVERSION, CAPLENGTH */
+        return 0x01000000 | LEN_CAP;
+    case 0x04: /* HCSPARAMS 1 */
+        return (MAXPORTS<<24) | (MAXINTRS<<8) | MAXSLOTS;
+    case 0x08: /* HCSPARAMS 2 */
+        return 0x0000000f;
+    case 0x0c: /* HCSPARAMS 3 */
+        return 0x00000000;
+    case 0x10: /* HCCPARAMS */
+#if TARGET_PHYS_ADDR_BITS > 32
+        return 0x00081001;
+#else
+        return 0x00081000;
+#endif
+    case 0x14: /* DBOFF */
+        return OFF_DOORBELL;
+    case 0x18: /* RTSOFF */
+        return OFF_RUNTIME;
+
+    /* extended capabilities */
+    case 0x20: /* Supported Protocol:00 */
+#if USB3_PORTS > 0
+        return 0x02000402; /* USB 2.0 */
+#else
+        return 0x02000002; /* USB 2.0 */
+#endif
+    case 0x24: /* Supported Protocol:04 */
+        return 0x20425455; /* "USB " */
+    case 0x28: /* Supported Protocol:08 */
+        return 0x00000001 | (USB2_PORTS<<8);
+    case 0x2c: /* Supported Protocol:0c */
+        return 0x00000000; /* reserved */
+#if USB3_PORTS > 0
+    case 0x30: /* Supported Protocol:00 */
+        return 0x03000002; /* USB 3.0 */
+    case 0x34: /* Supported Protocol:04 */
+        return 0x20425455; /* "USB " */
+    case 0x38: /* Supported Protocol:08 */
+        return 0x00000000 | (USB2_PORTS+1) | (USB3_PORTS<<8);
+    case 0x3c: /* Supported Protocol:0c */
+        return 0x00000000; /* reserved */
+#endif
+    default:
+        fprintf(stderr, "xhci_cap_read: reg %d unimplemented\n", reg);
+    }
+    return 0;
+}
+
+static uint32_t xhci_port_read(XHCIState *xhci, uint32_t reg)
+{
+    uint32_t port = reg >> 4;
+    if (port >= MAXPORTS) {
+        fprintf(stderr, "xhci_port_read: port %d out of bounds\n", port);
+        return 0;
+    }
+
+    switch (reg & 0xf) {
+    case 0x00: /* PORTSC */
+        return xhci->ports[port].portsc;
+    case 0x04: /* PORTPMSC */
+    case 0x08: /* PORTLI */
+        return 0;
+    case 0x0c: /* reserved */
+    default:
+        fprintf(stderr, "xhci_port_read (port %d): reg 0x%x unimplemented\n",
+                port, reg);
+        return 0;
+    }
+}
+
+static void xhci_port_write(XHCIState *xhci, uint32_t reg, uint32_t val)
+{
+    uint32_t port = reg >> 4;
+    uint32_t portsc;
+
+    if (port >= MAXPORTS) {
+        fprintf(stderr, "xhci_port_read: port %d out of bounds\n", port);
+        return;
+    }
+
+    switch (reg & 0xf) {
+    case 0x00: /* PORTSC */
+        portsc = xhci->ports[port].portsc;
+        /* write-1-to-clear bits*/
+        portsc &= ~(val & (PORTSC_CSC|PORTSC_PEC|PORTSC_WRC|PORTSC_OCC|
+                           PORTSC_PRC|PORTSC_PLC|PORTSC_CEC));
+        if (val & PORTSC_LWS) {
+            /* overwrite PLS only when LWS=1 */
+            portsc &= ~(PORTSC_PLS_MASK << PORTSC_PLS_SHIFT);
+            portsc |= val & (PORTSC_PLS_MASK << PORTSC_PLS_SHIFT);
+        }
+        /* read/write bits */
+        portsc &= ~(PORTSC_PP|PORTSC_WCE|PORTSC_WDE|PORTSC_WOE);
+        portsc |= (val & (PORTSC_PP|PORTSC_WCE|PORTSC_WDE|PORTSC_WOE));
+        /* write-1-to-start bits */
+        if (val & PORTSC_PR) {
+            DPRINTF("xhci: port %d reset\n", port);
+            if (xhci->ports[port].port.dev) {
+                usb_send_msg(xhci->ports[port].port.dev, USB_MSG_RESET);
+            }
+            portsc |= PORTSC_PRC | PORTSC_PED;
+        }
+        xhci->ports[port].portsc = portsc;
+        break;
+    case 0x04: /* PORTPMSC */
+    case 0x08: /* PORTLI */
+    default:
+        fprintf(stderr, "xhci_port_write (port %d): reg 0x%x unimplemented\n",
+                port, reg);
+    }
+}
+
+static uint32_t xhci_oper_read(XHCIState *xhci, uint32_t reg)
+{
+    DPRINTF("xhci_oper_read(0x%x)\n", reg);
+
+    if (reg >= 0x400) {
+        return xhci_port_read(xhci, reg - 0x400);
+    }
+
+    switch (reg) {
+    case 0x00: /* USBCMD */
+        return xhci->usbcmd;
+    case 0x04: /* USBSTS */
+        return xhci->usbsts;
+    case 0x08: /* PAGESIZE */
+        return 1; /* 4KiB */
+    case 0x14: /* DNCTRL */
+        return xhci->dnctrl;
+    case 0x18: /* CRCR low */
+        return xhci->crcr_low & ~0xe;
+    case 0x1c: /* CRCR high */
+        return xhci->crcr_high;
+    case 0x30: /* DCBAAP low */
+        return xhci->dcbaap_low;
+    case 0x34: /* DCBAAP high */
+        return xhci->dcbaap_high;
+    case 0x38: /* CONFIG */
+        return xhci->config;
+    default:
+        fprintf(stderr, "xhci_oper_read: reg 0x%x unimplemented\n", reg);
+    }
+    return 0;
+}
+
+static void xhci_oper_write(XHCIState *xhci, uint32_t reg, uint32_t val)
+{
+    DPRINTF("xhci_oper_write(0x%x, 0x%08x)\n", reg, val);
+
+    if (reg >= 0x400) {
+        xhci_port_write(xhci, reg - 0x400, val);
+        return;
+    }
+
+    switch (reg) {
+    case 0x00: /* USBCMD */
+        if ((val & USBCMD_RS) && !(xhci->usbcmd & USBCMD_RS)) {
+            xhci_run(xhci);
+        } else if (!(val & USBCMD_RS) && (xhci->usbcmd & USBCMD_RS)) {
+            xhci_stop(xhci);
+        }
+        xhci->usbcmd = val & 0xc0f;
+        if (val & USBCMD_HCRST) {
+            xhci_reset(xhci);
+        }
+        xhci_irq_update(xhci);
+        break;
+
+    case 0x04: /* USBSTS */
+        /* these bits are write-1-to-clear */
+        xhci->usbsts &= ~(val & (USBSTS_HSE|USBSTS_EINT|USBSTS_PCD|USBSTS_SRE));
+        xhci_irq_update(xhci);
+        break;
+
+    case 0x14: /* DNCTRL */
+        xhci->dnctrl = val & 0xffff;
+        break;
+    case 0x18: /* CRCR low */
+        xhci->crcr_low = (val & 0xffffffcf) | (xhci->crcr_low & CRCR_CRR);
+        break;
+    case 0x1c: /* CRCR high */
+        xhci->crcr_high = val;
+        if (xhci->crcr_low & (CRCR_CA|CRCR_CS) && (xhci->crcr_low & CRCR_CRR)) {
+            XHCIEvent event = {ER_COMMAND_COMPLETE, CC_COMMAND_RING_STOPPED};
+            xhci->crcr_low &= ~CRCR_CRR;
+            xhci_event(xhci, &event);
+            DPRINTF("xhci: command ring stopped (CRCR=%08x)\n", xhci->crcr_low);
+        } else {
+            target_phys_addr_t base = xhci_addr64(xhci->crcr_low & ~0x3f, val);
+            xhci_ring_init(xhci, &xhci->cmd_ring, base);
+        }
+        xhci->crcr_low &= ~(CRCR_CA | CRCR_CS);
+        break;
+    case 0x30: /* DCBAAP low */
+        xhci->dcbaap_low = val & 0xffffffc0;
+        break;
+    case 0x34: /* DCBAAP high */
+        xhci->dcbaap_high = val;
+        break;
+    case 0x38: /* CONFIG */
+        xhci->config = val & 0xff;
+        break;
+    default:
+        fprintf(stderr, "xhci_oper_write: reg 0x%x unimplemented\n", reg);
+    }
+}
+
+static uint32_t xhci_runtime_read(XHCIState *xhci, uint32_t reg)
+{
+    DPRINTF("xhci_runtime_read(0x%x)\n", reg);
+
+    switch (reg) {
+    case 0x00: /* MFINDEX */
+        fprintf(stderr, "xhci_runtime_read: MFINDEX not yet implemented\n");
+        return xhci->mfindex;
+    case 0x20: /* IMAN */
+        return xhci->iman;
+    case 0x24: /* IMOD */
+        return xhci->imod;
+    case 0x28: /* ERSTSZ */
+        return xhci->erstsz;
+    case 0x30: /* ERSTBA low */
+        return xhci->erstba_low;
+    case 0x34: /* ERSTBA high */
+        return xhci->erstba_high;
+    case 0x38: /* ERDP low */
+        return xhci->erdp_low;
+    case 0x3c: /* ERDP high */
+        return xhci->erdp_high;
+    default:
+        fprintf(stderr, "xhci_runtime_read: reg 0x%x unimplemented\n", reg);
+    }
+    return 0;
+}
+
+static void xhci_runtime_write(XHCIState *xhci, uint32_t reg, uint32_t val)
+{
+    DPRINTF("xhci_runtime_write(0x%x, 0x%08x)\n", reg, val);
+
+    switch (reg) {
+    case 0x20: /* IMAN */
+        if (val & IMAN_IP) {
+            xhci->iman &= ~IMAN_IP;
+        }
+        xhci->iman &= ~IMAN_IE;
+        xhci->iman |= val & IMAN_IE;
+        xhci_irq_update(xhci);
+        break;
+    case 0x24: /* IMOD */
+        xhci->imod = val;
+        break;
+    case 0x28: /* ERSTSZ */
+        xhci->erstsz = val & 0xffff;
+        break;
+    case 0x30: /* ERSTBA low */
+        /* XXX NEC driver bug: it doesn't align this to 64 bytes
+        xhci->erstba_low = val & 0xffffffc0; */
+        xhci->erstba_low = val & 0xfffffff0;
+        break;
+    case 0x34: /* ERSTBA high */
+        xhci->erstba_high = val;
+        xhci_er_reset(xhci);
+        break;
+    case 0x38: /* ERDP low */
+        if (val & ERDP_EHB) {
+            xhci->erdp_low &= ~ERDP_EHB;
+        }
+        xhci->erdp_low = (val & ~ERDP_EHB) | (xhci->erdp_low & ERDP_EHB);
+        break;
+    case 0x3c: /* ERDP high */
+        xhci->erdp_high = val;
+        xhci_events_update(xhci);
+        break;
+    default:
+        fprintf(stderr, "xhci_oper_write: reg 0x%x unimplemented\n", reg);
+    }
+}
+
+static uint32_t xhci_doorbell_read(XHCIState *xhci, uint32_t reg)
+{
+    DPRINTF("xhci_doorbell_read(0x%x)\n", reg);
+    /* doorbells always read as 0 */
+    return 0;
+}
+
+static void xhci_doorbell_write(XHCIState *xhci, uint32_t reg, uint32_t val)
+{
+    DPRINTF("xhci_doorbell_write(0x%x, 0x%08x)\n", reg, val);
+
+    if (!xhci_running(xhci)) {
+        fprintf(stderr, "xhci: wrote doorbell while xHC stopped or paused\n");
+        return;
+    }
+
+    reg >>= 2;
+
+    if (reg == 0) {
+        if (val == 0) {
+            xhci_process_commands(xhci);
+        } else {
+            fprintf(stderr, "xhci: bad doorbell 0 write: 0x%x\n", val);
+        }
+    } else {
+        if (reg > MAXSLOTS) {
+            fprintf(stderr, "xhci: bad doorbell %d\n", reg);
+        } else if (val > 31) {
+            fprintf(stderr, "xhci: bad doorbell %d write: 0x%x\n", reg, val);
+        } else {
+            xhci_kick_ep(xhci, reg, val);
+        }
+    }
+}
+
+static uint64_t xhci_mem_read(void *ptr, target_phys_addr_t addr,
+                              unsigned size)
+{
+    XHCIState *xhci = ptr;
+
+    /* Only aligned reads are allowed on xHCI */
+    if (addr & 3) {
+        fprintf(stderr, "xhci_mem_read: Mis-aligned read\n");
+        return 0;
+    }
+
+    if (addr < LEN_CAP) {
+        return xhci_cap_read(xhci, addr);
+    } else if (addr >= OFF_OPER && addr < (OFF_OPER + LEN_OPER)) {
+        return xhci_oper_read(xhci, addr - OFF_OPER);
+    } else if (addr >= OFF_RUNTIME && addr < (OFF_RUNTIME + LEN_RUNTIME)) {
+        return xhci_runtime_read(xhci, addr - OFF_RUNTIME);
+    } else if (addr >= OFF_DOORBELL && addr < (OFF_DOORBELL + LEN_DOORBELL)) {
+        return xhci_doorbell_read(xhci, addr - OFF_DOORBELL);
+    } else {
+        fprintf(stderr, "xhci_mem_read: Bad offset %x\n", (int)addr);
+        return 0;
+    }
+}
+
+static void xhci_mem_write(void *ptr, target_phys_addr_t addr,
+                           uint64_t val, unsigned size)
+{
+    XHCIState *xhci = ptr;
+
+    /* Only aligned writes are allowed on xHCI */
+    if (addr & 3) {
+        fprintf(stderr, "xhci_mem_write: Mis-aligned write\n");
+        return;
+    }
+
+    if (addr >= OFF_OPER && addr < (OFF_OPER + LEN_OPER)) {
+        xhci_oper_write(xhci, addr - OFF_OPER, val);
+    } else if (addr >= OFF_RUNTIME && addr < (OFF_RUNTIME + LEN_RUNTIME)) {
+        xhci_runtime_write(xhci, addr - OFF_RUNTIME, val);
+    } else if (addr >= OFF_DOORBELL && addr < (OFF_DOORBELL + LEN_DOORBELL)) {
+        xhci_doorbell_write(xhci, addr - OFF_DOORBELL, val);
+    } else {
+        fprintf(stderr, "xhci_mem_write: Bad offset %x\n", (int)addr);
+    }
+}
+
+static const MemoryRegionOps xhci_mem_ops = {
+    .read = xhci_mem_read,
+    .write = xhci_mem_write,
+    .valid.min_access_size = 4,
+    .valid.max_access_size = 4,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void xhci_attach(USBPort *usbport)
+{
+    XHCIState *xhci = usbport->opaque;
+    XHCIPort *port = &xhci->ports[usbport->index];
+
+    xhci_update_port(xhci, port, 0);
+}
+
+static void xhci_detach(USBPort *usbport)
+{
+    XHCIState *xhci = usbport->opaque;
+    XHCIPort *port = &xhci->ports[usbport->index];
+
+    xhci_update_port(xhci, port, 1);
+}
+
+static void xhci_complete(USBPort *port, USBPacket *packet)
+{
+    XHCITransfer *xfer = container_of(packet, XHCITransfer, packet);
+
+    xhci_complete_packet(xfer, packet->result);
+    xhci_kick_ep(xfer->xhci, xfer->slotid, xfer->epid);
+}
+
+static void xhci_child_detach(USBPort *port, USBDevice *child)
+{
+    FIXME();
+}
+
+static USBPortOps xhci_port_ops = {
+    .attach   = xhci_attach,
+    .detach   = xhci_detach,
+    .complete = xhci_complete,
+    .child_detach = xhci_child_detach,
+};
+
+static USBBusOps xhci_bus_ops = {
+};
+
+static void usb_xhci_init(XHCIState *xhci, DeviceState *dev)
+{
+    int i;
+
+    xhci->usbsts = USBSTS_HCH;
+
+    usb_bus_new(&xhci->bus, &xhci_bus_ops, &xhci->pci_dev.qdev);
+
+    for (i = 0; i < MAXPORTS; i++) {
+        memset(&xhci->ports[i], 0, sizeof(xhci->ports[i]));
+        usb_register_port(&xhci->bus, &xhci->ports[i].port, xhci, i,
+                          &xhci_port_ops, USB_SPEED_MASK_HIGH);
+    }
+    for (i = 0; i < MAXSLOTS; i++) {
+        xhci->slots[i].enabled = 0;
+    }
+
+    qemu_register_reset(xhci_reset, xhci);
+}
+
+static int usb_xhci_initfn(struct PCIDevice *dev)
+{
+    int ret;
+
+    XHCIState *xhci = DO_UPCAST(XHCIState, pci_dev, dev);
+
+    xhci->pci_dev.config[PCI_CLASS_PROG] = 0x30;    /* xHCI */
+    xhci->pci_dev.config[PCI_INTERRUPT_PIN] = 0x01; /* interrupt pin 1 */
+    xhci->pci_dev.config[PCI_CACHE_LINE_SIZE] = 0x10;
+    xhci->pci_dev.config[0x60] = 0x30; /* release number */
+
+    usb_xhci_init(xhci, &dev->qdev);
+
+    xhci->irq = xhci->pci_dev.irq[0];
+
+    memory_region_init_io(&xhci->mem, &xhci_mem_ops, xhci,
+                          "xhci", LEN_REGS);
+    pci_register_bar(&xhci->pci_dev, 0,
+                     PCI_BASE_ADDRESS_SPACE_MEMORY|PCI_BASE_ADDRESS_MEM_TYPE_64,
+                     &xhci->mem);
+
+    ret = pcie_cap_init(&xhci->pci_dev, 0xa0, PCI_EXP_TYPE_ENDPOINT, 0);
+    assert(ret >= 0);
+
+    if (xhci->msi) {
+        ret = msi_init(&xhci->pci_dev, 0x70, 1, true, false);
+        assert(ret >= 0);
+    }
+
+    return 0;
+}
+
+static void xhci_write_config(PCIDevice *dev, uint32_t addr, uint32_t val,
+                              int len)
+{
+    XHCIState *xhci = DO_UPCAST(XHCIState, pci_dev, dev);
+
+    pci_default_write_config(dev, addr, val, len);
+    if (xhci->msi) {
+        msi_write_config(dev, addr, val, len);
+    }
+}
+
+static const VMStateDescription vmstate_xhci = {
+    .name = "xhci",
+    .unmigratable = 1,
+};
+
+static PCIDeviceInfo xhci_info = {
+    .qdev.name    = "nec-usb-xhci",
+    .qdev.alias   = "xhci",
+    .qdev.size    = sizeof(XHCIState),
+    .qdev.vmsd    = &vmstate_xhci,
+    .init         = usb_xhci_initfn,
+    .vendor_id    = PCI_VENDOR_ID_NEC,
+    .device_id    = PCI_DEVICE_ID_NEC_UPD720200,
+    .class_id     = PCI_CLASS_SERIAL_USB,
+    .revision     = 0x03,
+    .is_express   = 1,
+    .config_write = xhci_write_config,
+    .qdev.props   = (Property[]) {
+        DEFINE_PROP_UINT32("msi", XHCIState, msi, 0),
+        DEFINE_PROP_END_OF_LIST(),
+    }
+};
+
+static void xhci_register(void)
+{
+    pci_qdev_register(&xhci_info);
+}
+device_init(xhci_register);