Merge remote-tracking branch 'kraxel/usb.14.pull' into staging

18 files changed, 2263 insertions, 80 deletions

diff --git a/hw/bt-hid.c b/hw/bt-hid.c
index abdfd35..09120af 100644
--- a/hw/bt-hid.c
+++ b/hw/bt-hid.c
@@ -323,7 +323,7 @@ static void bt_hid_control_transaction(struct bt_hid_device_s *s,
             break;
         }
         s->proto = parameter;
-        s->usbdev->info->handle_control(s->usbdev, SET_PROTOCOL, s->proto, 0, 0,
+        s->usbdev->info->handle_control(s->usbdev, NULL, SET_PROTOCOL, s->proto, 0, 0,
                                         NULL);
         ret = BT_HS_SUCCESSFUL;
         break;
@@ -333,7 +333,7 @@ static void bt_hid_control_transaction(struct bt_hid_device_s *s,
             ret = BT_HS_ERR_INVALID_PARAMETER;
             break;
         }
-        s->usbdev->info->handle_control(s->usbdev, GET_IDLE, 0, 0, 1,
+        s->usbdev->info->handle_control(s->usbdev, NULL, GET_IDLE, 0, 0, 1,
                         s->control->sdu_out(s->control, 1));
         s->control->sdu_submit(s->control);
         break;
@@ -346,7 +346,7 @@ static void bt_hid_control_transaction(struct bt_hid_device_s *s,
 
         /* We don't need to know about the Idle Rate here really,
          * so just pass it on to the device.  */
-        ret = s->usbdev->info->handle_control(s->usbdev,
+        ret = s->usbdev->info->handle_control(s->usbdev, NULL,
                         SET_IDLE, data[1], 0, 0, NULL) ?
                 BT_HS_SUCCESSFUL : BT_HS_ERR_INVALID_PARAMETER;
         /* XXX: Does this generate a handshake? */
diff --git a/hw/pci_ids.h b/hw/pci_ids.h
index ea3418c..d9457ed 100644
--- a/hw/pci_ids.h
+++ b/hw/pci_ids.h
@@ -100,6 +100,7 @@
 #define PCI_VENDOR_ID_INTEL              0x8086
 #define PCI_DEVICE_ID_INTEL_82441        0x1237
 #define PCI_DEVICE_ID_INTEL_82801AA_5    0x2415
+#define PCI_DEVICE_ID_INTEL_82801D       0x24CD
 #define PCI_DEVICE_ID_INTEL_ESB_9        0x25ab
 #define PCI_DEVICE_ID_INTEL_82371SB_0    0x7000
 #define PCI_DEVICE_ID_INTEL_82371SB_1    0x7010
diff --git a/hw/usb-bt.c b/hw/usb-bt.c
index 22e6845..baae487 100644
--- a/hw/usb-bt.c
+++ b/hw/usb-bt.c
@@ -372,13 +372,13 @@ static void usb_bt_handle_reset(USBDevice *dev)
     s->altsetting = 0;
 }
 
-static int usb_bt_handle_control(USBDevice *dev, int request, int value,
-                int index, int length, uint8_t *data)
+static int usb_bt_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     struct USBBtState *s = (struct USBBtState *) dev->opaque;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         switch (request) {
         case DeviceRequest | USB_REQ_GET_CONFIGURATION:
diff --git a/hw/usb-ccid.c b/hw/usb-ccid.c
index 079b4a2..5b6878b 100644
--- a/hw/usb-ccid.c
+++ b/hw/usb-ccid.c
@@ -602,8 +602,8 @@ static void ccid_handle_reset(USBDevice *dev)
     ccid_reset(s);
 }
 
-static int ccid_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int ccid_handle_control(USBDevice *dev, USBPacket *p, int request,
+                               int value, int index, int length, uint8_t *data)
 {
     USBCCIDState *s = DO_UPCAST(USBCCIDState, dev, dev);
     int ret = 0;
diff --git a/hw/usb-desc.c b/hw/usb-desc.c
index 62591f2..e4a4680 100644
--- a/hw/usb-desc.c
+++ b/hw/usb-desc.c
@@ -76,7 +76,7 @@ int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len)
 {
     uint8_t  bLength = 0x09;
     uint16_t wTotalLength = 0;
-    int i, rc, count;
+    int i, rc;
 
     if (len < bLength) {
         return -1;
@@ -91,8 +91,19 @@ int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len)
     dest[0x08] = conf->bMaxPower;
     wTotalLength += bLength;
 
-    count = conf->nif ? conf->nif : conf->bNumInterfaces;
-    for (i = 0; i < count; i++) {
+    /* handle grouped interfaces if any*/
+    for (i = 0; i < conf->nif_groups; i++) {
+        rc = usb_desc_iface_group(&(conf->if_groups[i]),
+                                  dest + wTotalLength,
+                                  len - wTotalLength);
+        if (rc < 0) {
+            return rc;
+        }
+        wTotalLength += rc;
+    }
+
+    /* handle normal (ungrouped / no IAD) interfaces if any */
+    for (i = 0; i < conf->nif; i++) {
         rc = usb_desc_iface(conf->ifs + i, dest + wTotalLength, len - wTotalLength);
         if (rc < 0) {
             return rc;
@@ -105,6 +116,41 @@ int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len)
     return wTotalLength;
 }
 
+int usb_desc_iface_group(const USBDescIfaceAssoc *iad, uint8_t *dest,
+                         size_t len)
+{
+    int pos = 0;
+    int i = 0;
+
+    /* handle interface association descriptor */
+    uint8_t bLength = 0x08;
+
+    if (len < bLength) {
+        return -1;
+    }
+
+    dest[0x00] = bLength;
+    dest[0x01] = USB_DT_INTERFACE_ASSOC;
+    dest[0x02] = iad->bFirstInterface;
+    dest[0x03] = iad->bInterfaceCount;
+    dest[0x04] = iad->bFunctionClass;
+    dest[0x05] = iad->bFunctionSubClass;
+    dest[0x06] = iad->bFunctionProtocol;
+    dest[0x07] = iad->iFunction;
+    pos += bLength;
+
+    /* handle associated interfaces in this group */
+    for (i = 0; i < iad->nif; i++) {
+        int rc = usb_desc_iface(&(iad->ifs[i]), dest + pos, len - pos);
+        if (rc < 0) {
+            return rc;
+        }
+        pos += rc;
+    }
+
+    return pos;
+}
+
 int usb_desc_iface(const USBDescIface *iface, uint8_t *dest, size_t len)
 {
     uint8_t bLength = 0x09;
@@ -344,8 +390,8 @@ int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len
     return ret;
 }
 
-int usb_desc_handle_control(USBDevice *dev, int request, int value,
-                            int index, int length, uint8_t *data)
+int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
+        int request, int value, int index, int length, uint8_t *data)
 {
     const USBDesc *desc = dev->info->usb_desc;
     int i, ret = -1;
diff --git a/hw/usb-desc.h b/hw/usb-desc.h
index ac734ab..9d7ed59 100644
--- a/hw/usb-desc.h
+++ b/hw/usb-desc.h
@@ -30,6 +30,24 @@ struct USBDescConfig {
     uint8_t                   bmAttributes;
     uint8_t                   bMaxPower;
 
+    /* grouped interfaces */
+    uint8_t                   nif_groups;
+    const USBDescIfaceAssoc   *if_groups;
+
+    /* "normal" interfaces */
+    uint8_t                   nif;
+    const USBDescIface        *ifs;
+};
+
+/* conceptually an Interface Association Descriptor, and releated interfaces */
+struct USBDescIfaceAssoc {
+    uint8_t                   bFirstInterface;
+    uint8_t                   bInterfaceCount;
+    uint8_t                   bFunctionClass;
+    uint8_t                   bFunctionSubClass;
+    uint8_t                   bFunctionProtocol;
+    uint8_t                   iFunction;
+
     uint8_t                   nif;
     const USBDescIface        *ifs;
 };
@@ -75,6 +93,8 @@ int usb_desc_device(const USBDescID *id, const USBDescDevice *dev,
 int usb_desc_device_qualifier(const USBDescDevice *dev,
                               uint8_t *dest, size_t len);
 int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len);
+int usb_desc_iface_group(const USBDescIfaceAssoc *iad, uint8_t *dest,
+                         size_t len);
 int usb_desc_iface(const USBDescIface *iface, uint8_t *dest, size_t len);
 int usb_desc_endpoint(const USBDescEndpoint *ep, uint8_t *dest, size_t len);
 int usb_desc_other(const USBDescOther *desc, uint8_t *dest, size_t len);
@@ -86,7 +106,7 @@ void usb_desc_set_string(USBDevice *dev, uint8_t index, const char *str);
 const char *usb_desc_get_string(USBDevice *dev, uint8_t index);
 int usb_desc_string(USBDevice *dev, int index, uint8_t *dest, size_t len);
 int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len);
-int usb_desc_handle_control(USBDevice *dev, int request, int value,
-                            int index, int length, uint8_t *data);
+int usb_desc_handle_control(USBDevice *dev, USBPacket *p,
+        int request, int value, int index, int length, uint8_t *data);
 
 #endif /* QEMU_HW_USB_DESC_H */
diff --git a/hw/usb-ehci.c b/hw/usb-ehci.c
new file mode 100644
index 0000000..f63519e
--- /dev/null
+++ b/hw/usb-ehci.c
@@ -0,0 +1,2037 @@
+/*
+ * QEMU USB EHCI Emulation
+ *
+ * Copyright(c) 2008  Emutex Ltd. (address@hidden)
+ *
+ * EHCI project was started by Mark Burkley, with contributions by
+ * Niels de Vos.  David S. Ahern continued working on it.  Kevin Wolf,
+ * Jan Kiszka and Vincent Palatin contributed bugfixes.
+ *
+ *
+ * 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 General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * TODO:
+ *  o Downstream port handoff
+ */
+
+#include "hw.h"
+#include "qemu-timer.h"
+#include "usb.h"
+#include "pci.h"
+#include "monitor.h"
+
+#define EHCI_DEBUG   0
+#define STATE_DEBUG  0       /* state transitions  */
+
+#if EHCI_DEBUG || STATE_DEBUG
+#define DPRINTF printf
+#else
+#define DPRINTF(...)
+#endif
+
+#if STATE_DEBUG
+#define DPRINTF_ST DPRINTF
+#else
+#define DPRINTF_ST(...)
+#endif
+
+/* internal processing - reset HC to try and recover */
+#define USB_RET_PROCERR   (-99)
+
+#define MMIO_SIZE        0x1000
+
+/* Capability Registers Base Address - section 2.2 */
+#define CAPREGBASE       0x0000
+#define CAPLENGTH        CAPREGBASE + 0x0000  // 1-byte, 0x0001 reserved
+#define HCIVERSION       CAPREGBASE + 0x0002  // 2-bytes, i/f version #
+#define HCSPARAMS        CAPREGBASE + 0x0004  // 4-bytes, structural params
+#define HCCPARAMS        CAPREGBASE + 0x0008  // 4-bytes, capability params
+#define EECP             HCCPARAMS + 1
+#define HCSPPORTROUTE1   CAPREGBASE + 0x000c
+#define HCSPPORTROUTE2   CAPREGBASE + 0x0010
+
+#define OPREGBASE        0x0020        // Operational Registers Base Address
+
+#define USBCMD           OPREGBASE + 0x0000
+#define USBCMD_RUNSTOP   (1 << 0)      // run / Stop
+#define USBCMD_HCRESET   (1 << 1)      // HC Reset
+#define USBCMD_FLS       (3 << 2)      // Frame List Size
+#define USBCMD_FLS_SH    2             // Frame List Size Shift
+#define USBCMD_PSE       (1 << 4)      // Periodic Schedule Enable
+#define USBCMD_ASE       (1 << 5)      // Asynch Schedule Enable
+#define USBCMD_IAAD      (1 << 6)      // Int Asynch Advance Doorbell
+#define USBCMD_LHCR      (1 << 7)      // Light Host Controller Reset
+#define USBCMD_ASPMC     (3 << 8)      // Async Sched Park Mode Count
+#define USBCMD_ASPME     (1 << 11)     // Async Sched Park Mode Enable
+#define USBCMD_ITC       (0x7f << 16)  // Int Threshold Control
+#define USBCMD_ITC_SH    16            // Int Threshold Control Shift
+
+#define USBSTS           OPREGBASE + 0x0004
+#define USBSTS_RO_MASK   0x0000003f
+#define USBSTS_INT       (1 << 0)      // USB Interrupt
+#define USBSTS_ERRINT    (1 << 1)      // Error Interrupt
+#define USBSTS_PCD       (1 << 2)      // Port Change Detect
+#define USBSTS_FLR       (1 << 3)      // Frame List Rollover
+#define USBSTS_HSE       (1 << 4)      // Host System Error
+#define USBSTS_IAA       (1 << 5)      // Interrupt on Async Advance
+#define USBSTS_HALT      (1 << 12)     // HC Halted
+#define USBSTS_REC       (1 << 13)     // Reclamation
+#define USBSTS_PSS       (1 << 14)     // Periodic Schedule Status
+#define USBSTS_ASS       (1 << 15)     // Asynchronous Schedule Status
+
+/*
+ *  Interrupt enable bits correspond to the interrupt active bits in USBSTS
+ *  so no need to redefine here.
+ */
+#define USBINTR              OPREGBASE + 0x0008
+#define USBINTR_MASK         0x0000003f
+
+#define FRINDEX              OPREGBASE + 0x000c
+#define CTRLDSSEGMENT        OPREGBASE + 0x0010
+#define PERIODICLISTBASE     OPREGBASE + 0x0014
+#define ASYNCLISTADDR        OPREGBASE + 0x0018
+#define ASYNCLISTADDR_MASK   0xffffffe0
+
+#define CONFIGFLAG           OPREGBASE + 0x0040
+
+#define PORTSC               (OPREGBASE + 0x0044)
+#define PORTSC_BEGIN         PORTSC
+#define PORTSC_END           (PORTSC + 4 * NB_PORTS)
+/*
+ * Bits that are reserverd or are read-only are masked out of values
+ * written to us by software
+ */
+#define PORTSC_RO_MASK       0x007021c5
+#define PORTSC_RWC_MASK      0x0000002a
+#define PORTSC_WKOC_E        (1 << 22)    // Wake on Over Current Enable
+#define PORTSC_WKDS_E        (1 << 21)    // Wake on Disconnect Enable
+#define PORTSC_WKCN_E        (1 << 20)    // Wake on Connect Enable
+#define PORTSC_PTC           (15 << 16)   // Port Test Control
+#define PORTSC_PTC_SH        16           // Port Test Control shift
+#define PORTSC_PIC           (3 << 14)    // Port Indicator Control
+#define PORTSC_PIC_SH        14           // Port Indicator Control Shift
+#define PORTSC_POWNER        (1 << 13)    // Port Owner
+#define PORTSC_PPOWER        (1 << 12)    // Port Power
+#define PORTSC_LINESTAT      (3 << 10)    // Port Line Status
+#define PORTSC_LINESTAT_SH   10           // Port Line Status Shift
+#define PORTSC_PRESET        (1 << 8)     // Port Reset
+#define PORTSC_SUSPEND       (1 << 7)     // Port Suspend
+#define PORTSC_FPRES         (1 << 6)     // Force Port Resume
+#define PORTSC_OCC           (1 << 5)     // Over Current Change
+#define PORTSC_OCA           (1 << 4)     // Over Current Active
+#define PORTSC_PEDC          (1 << 3)     // Port Enable/Disable Change
+#define PORTSC_PED           (1 << 2)     // Port Enable/Disable
+#define PORTSC_CSC           (1 << 1)     // Connect Status Change
+#define PORTSC_CONNECT       (1 << 0)     // Current Connect Status
+
+#define FRAME_TIMER_FREQ 1000
+#define FRAME_TIMER_USEC (1000000 / FRAME_TIMER_FREQ)
+
+#define NB_MAXINTRATE    8        // Max rate at which controller issues ints
+#define NB_PORTS         4        // Number of downstream ports
+#define BUFF_SIZE        5*4096   // Max bytes to transfer per transaction
+#define MAX_ITERATIONS   20       // Max number of QH before we break the loop
+#define MAX_QH           100      // Max allowable queue heads in a chain
+
+/*  Internal periodic / asynchronous schedule state machine states
+ */
+typedef enum {
+    EST_INACTIVE = 1000,
+    EST_ACTIVE,
+    EST_EXECUTING,
+    EST_SLEEPING,
+    /*  The following states are internal to the state machine function
+    */
+    EST_WAITLISTHEAD,
+    EST_FETCHENTRY,
+    EST_FETCHQH,
+    EST_FETCHITD,
+    EST_ADVANCEQUEUE,
+    EST_FETCHQTD,
+    EST_EXECUTE,
+    EST_WRITEBACK,
+    EST_HORIZONTALQH
+} EHCI_STATES;
+
+/* macros for accessing fields within next link pointer entry */
+#define NLPTR_GET(x)             ((x) & 0xffffffe0)
+#define NLPTR_TYPE_GET(x)        (((x) >> 1) & 3)
+#define NLPTR_TBIT(x)            ((x) & 1)  // 1=invalid, 0=valid
+
+/* link pointer types */
+#define NLPTR_TYPE_ITD           0     // isoc xfer descriptor
+#define NLPTR_TYPE_QH            1     // queue head
+#define NLPTR_TYPE_STITD         2     // split xaction, isoc xfer descriptor
+#define NLPTR_TYPE_FSTN          3     // frame span traversal node
+
+
+/*  EHCI spec version 1.0 Section 3.3
+ */
+typedef struct EHCIitd {
+    uint32_t next;
+
+    uint32_t transact[8];
+#define ITD_XACT_ACTIVE          (1 << 31)
+#define ITD_XACT_DBERROR         (1 << 30)
+#define ITD_XACT_BABBLE          (1 << 29)
+#define ITD_XACT_XACTERR         (1 << 28)
+#define ITD_XACT_LENGTH_MASK     0x0fff0000
+#define ITD_XACT_LENGTH_SH       16
+#define ITD_XACT_IOC             (1 << 15)
+#define ITD_XACT_PGSEL_MASK      0x00007000
+#define ITD_XACT_PGSEL_SH        12
+#define ITD_XACT_OFFSET_MASK     0x00000fff
+
+    uint32_t bufptr[7];
+#define ITD_BUFPTR_MASK          0xfffff000
+#define ITD_BUFPTR_SH            12
+#define ITD_BUFPTR_EP_MASK       0x00000f00
+#define ITD_BUFPTR_EP_SH         8
+#define ITD_BUFPTR_DEVADDR_MASK  0x0000007f
+#define ITD_BUFPTR_DEVADDR_SH    0
+#define ITD_BUFPTR_DIRECTION     (1 << 11)
+#define ITD_BUFPTR_MAXPKT_MASK   0x000007ff
+#define ITD_BUFPTR_MAXPKT_SH     0
+#define ITD_BUFPTR_MULT_MASK     0x00000003
+} EHCIitd;
+
+/*  EHCI spec version 1.0 Section 3.4
+ */
+typedef struct EHCIsitd {
+    uint32_t next;                  // Standard next link pointer
+    uint32_t epchar;
+#define SITD_EPCHAR_IO              (1 << 31)
+#define SITD_EPCHAR_PORTNUM_MASK    0x7f000000
+#define SITD_EPCHAR_PORTNUM_SH      24
+#define SITD_EPCHAR_HUBADD_MASK     0x007f0000
+#define SITD_EPCHAR_HUBADDR_SH      16
+#define SITD_EPCHAR_EPNUM_MASK      0x00000f00
+#define SITD_EPCHAR_EPNUM_SH        8
+#define SITD_EPCHAR_DEVADDR_MASK    0x0000007f
+
+    uint32_t uframe;
+#define SITD_UFRAME_CMASK_MASK      0x0000ff00
+#define SITD_UFRAME_CMASK_SH        8
+#define SITD_UFRAME_SMASK_MASK      0x000000ff
+
+    uint32_t results;
+#define SITD_RESULTS_IOC              (1 << 31)
+#define SITD_RESULTS_PGSEL            (1 << 30)
+#define SITD_RESULTS_TBYTES_MASK      0x03ff0000
+#define SITD_RESULTS_TYBYTES_SH       16
+#define SITD_RESULTS_CPROGMASK_MASK   0x0000ff00
+#define SITD_RESULTS_CPROGMASK_SH     8
+#define SITD_RESULTS_ACTIVE           (1 << 7)
+#define SITD_RESULTS_ERR              (1 << 6)
+#define SITD_RESULTS_DBERR            (1 << 5)
+#define SITD_RESULTS_BABBLE           (1 << 4)
+#define SITD_RESULTS_XACTERR          (1 << 3)
+#define SITD_RESULTS_MISSEDUF         (1 << 2)
+#define SITD_RESULTS_SPLITXSTATE      (1 << 1)
+
+    uint32_t bufptr[2];
+#define SITD_BUFPTR_MASK              0xfffff000
+#define SITD_BUFPTR_CURROFF_MASK      0x00000fff
+#define SITD_BUFPTR_TPOS_MASK         0x00000018
+#define SITD_BUFPTR_TPOS_SH           3
+#define SITD_BUFPTR_TCNT_MASK         0x00000007
+
+    uint32_t backptr;                 // Standard next link pointer
+} EHCIsitd;
+
+/*  EHCI spec version 1.0 Section 3.5
+ */
+typedef struct EHCIqtd {
+    uint32_t next;                    // Standard next link pointer
+    uint32_t altnext;                 // Standard next link pointer
+    uint32_t token;
+#define QTD_TOKEN_DTOGGLE             (1 << 31)
+#define QTD_TOKEN_TBYTES_MASK         0x7fff0000
+#define QTD_TOKEN_TBYTES_SH           16
+#define QTD_TOKEN_IOC                 (1 << 15)
+#define QTD_TOKEN_CPAGE_MASK          0x00007000
+#define QTD_TOKEN_CPAGE_SH            12
+#define QTD_TOKEN_CERR_MASK           0x00000c00
+#define QTD_TOKEN_CERR_SH             10
+#define QTD_TOKEN_PID_MASK            0x00000300
+#define QTD_TOKEN_PID_SH              8
+#define QTD_TOKEN_ACTIVE              (1 << 7)
+#define QTD_TOKEN_HALT                (1 << 6)
+#define QTD_TOKEN_DBERR               (1 << 5)
+#define QTD_TOKEN_BABBLE              (1 << 4)
+#define QTD_TOKEN_XACTERR             (1 << 3)
+#define QTD_TOKEN_MISSEDUF            (1 << 2)
+#define QTD_TOKEN_SPLITXSTATE         (1 << 1)
+#define QTD_TOKEN_PING                (1 << 0)
+
+    uint32_t bufptr[5];               // Standard buffer pointer
+#define QTD_BUFPTR_MASK               0xfffff000
+} EHCIqtd;
+
+/*  EHCI spec version 1.0 Section 3.6
+ */
+typedef struct EHCIqh {
+    uint32_t next;                    // Standard next link pointer
+
+    /* endpoint characteristics */
+    uint32_t epchar;
+#define QH_EPCHAR_RL_MASK             0xf0000000
+#define QH_EPCHAR_RL_SH               28
+#define QH_EPCHAR_C                   (1 << 27)
+#define QH_EPCHAR_MPLEN_MASK          0x07FF0000
+#define QH_EPCHAR_MPLEN_SH            16
+#define QH_EPCHAR_H                   (1 << 15)
+#define QH_EPCHAR_DTC                 (1 << 14)
+#define QH_EPCHAR_EPS_MASK            0x00003000
+#define QH_EPCHAR_EPS_SH              12
+#define EHCI_QH_EPS_FULL              0
+#define EHCI_QH_EPS_LOW               1
+#define EHCI_QH_EPS_HIGH              2
+#define EHCI_QH_EPS_RESERVED          3
+
+#define QH_EPCHAR_EP_MASK             0x00000f00
+#define QH_EPCHAR_EP_SH               8
+#define QH_EPCHAR_I                   (1 << 7)
+#define QH_EPCHAR_DEVADDR_MASK        0x0000007f
+#define QH_EPCHAR_DEVADDR_SH          0
+
+    /* endpoint capabilities */
+    uint32_t epcap;
+#define QH_EPCAP_MULT_MASK            0xc0000000
+#define QH_EPCAP_MULT_SH              30
+#define QH_EPCAP_PORTNUM_MASK         0x3f800000
+#define QH_EPCAP_PORTNUM_SH           23
+#define QH_EPCAP_HUBADDR_MASK         0x007f0000
+#define QH_EPCAP_HUBADDR_SH           16
+#define QH_EPCAP_CMASK_MASK           0x0000ff00
+#define QH_EPCAP_CMASK_SH             8
+#define QH_EPCAP_SMASK_MASK           0x000000ff
+#define QH_EPCAP_SMASK_SH             0
+
+    uint32_t current_qtd;             // Standard next link pointer
+    uint32_t next_qtd;                // Standard next link pointer
+    uint32_t altnext_qtd;
+#define QH_ALTNEXT_NAKCNT_MASK        0x0000001e
+#define QH_ALTNEXT_NAKCNT_SH          1
+
+    uint32_t token;                   // Same as QTD token
+    uint32_t bufptr[5];               // Standard buffer pointer
+#define BUFPTR_CPROGMASK_MASK         0x000000ff
+#define BUFPTR_FRAMETAG_MASK          0x0000001f
+#define BUFPTR_SBYTES_MASK            0x00000fe0
+#define BUFPTR_SBYTES_SH              5
+} EHCIqh;
+
+/*  EHCI spec version 1.0 Section 3.7
+ */
+typedef struct EHCIfstn {
+    uint32_t next;                    // Standard next link pointer
+    uint32_t backptr;                 // Standard next link pointer
+} EHCIfstn;
+
+typedef struct {
+    PCIDevice dev;
+    qemu_irq irq;
+    target_phys_addr_t mem_base;
+    int mem;
+    int num_ports;
+    /*
+     *  EHCI spec version 1.0 Section 2.3
+     *  Host Controller Operational Registers
+     */
+    union {
+        uint8_t mmio[MMIO_SIZE];
+        struct {
+            uint8_t cap[OPREGBASE];
+            uint32_t usbcmd;
+            uint32_t usbsts;
+            uint32_t usbintr;
+            uint32_t frindex;
+            uint32_t ctrldssegment;
+            uint32_t periodiclistbase;
+            uint32_t asynclistaddr;
+            uint32_t notused[9];
+            uint32_t configflag;
+            uint32_t portsc[NB_PORTS];
+        };
+    };
+    /*
+     *  Internal states, shadow registers, etc
+     */
+    uint32_t sofv;
+    QEMUTimer *frame_timer;
+    int attach_poll_counter;
+    int astate;                        // Current state in asynchronous schedule
+    int pstate;                        // Current state in periodic schedule
+    USBPort ports[NB_PORTS];
+    uint8_t buffer[BUFF_SIZE];
+    uint32_t usbsts_pending;
+
+    /* cached data from guest - needs to be flushed
+     * when guest removes an entry (doorbell, handshake sequence)
+     */
+    EHCIqh qh;             // copy of current QH (being worked on)
+    uint32_t qhaddr;       // address QH read from
+
+    EHCIqtd qtd;           // copy of current QTD (being worked on)
+    uint32_t qtdaddr;      // address QTD read from
+
+    uint32_t itdaddr;      // current ITD
+
+    uint32_t fetch_addr;   // which address to look at next
+
+    USBBus bus;
+    USBPacket usb_packet;
+    int async_complete;
+    uint32_t tbytes;
+    int pid;
+    int exec_status;
+    int isoch_pause;
+    uint32_t last_run_usec;
+    uint32_t frame_end_usec;
+} EHCIState;
+
+#define SET_LAST_RUN_CLOCK(s) \
+    (s)->last_run_usec = qemu_get_clock_ns(vm_clock) / 1000;
+
+/* nifty macros from Arnon's EHCI version  */
+#define get_field(data, field) \
+    (((data) & field##_MASK) >> field##_SH)
+
+#define set_field(data, newval, field) do { \
+    uint32_t val = *data; \
+    val &= ~ field##_MASK; \
+    val |= ((newval) << field##_SH) & field##_MASK; \
+    *data = val; \
+    } while(0)
+
+
+#if EHCI_DEBUG
+static const char *addr2str(unsigned addr)
+{
+    const char *r            = "   unknown";
+    const char *n[] = {
+        [ CAPLENGTH ]        = " CAPLENGTH",
+        [ HCIVERSION ]       = "HCIVERSION",
+        [ HCSPARAMS ]        = " HCSPARAMS",
+        [ HCCPARAMS ]        = " HCCPARAMS",
+        [ USBCMD ]           = "   COMMAND",
+        [ USBSTS ]           = "    STATUS",
+        [ USBINTR ]          = " INTERRUPT",
+        [ FRINDEX ]          = " FRAME IDX",
+        [ PERIODICLISTBASE ] = "P-LIST BASE",
+        [ ASYNCLISTADDR ]    = "A-LIST ADDR",
+        [ PORTSC_BEGIN ...
+          PORTSC_END ]       = "PORT STATUS",
+        [ CONFIGFLAG ]       = "CONFIG FLAG",
+    };
+
+    if (addr < ARRAY_SIZE(n) && n[addr] != NULL) {
+        return n[addr];
+    } else {
+        return r;
+    }
+}
+#endif
+
+
+static inline void ehci_set_interrupt(EHCIState *s, int intr)
+{
+    int level = 0;
+
+    // TODO honour interrupt threshold requests
+
+    s->usbsts |= intr;
+
+    if ((s->usbsts & USBINTR_MASK) & s->usbintr) {
+        level = 1;
+    }
+
+    qemu_set_irq(s->irq, level);
+}
+
+static inline void ehci_record_interrupt(EHCIState *s, int intr)
+{
+    s->usbsts_pending |= intr;
+}
+
+static inline void ehci_commit_interrupt(EHCIState *s)
+{
+    if (!s->usbsts_pending) {
+        return;
+    }
+    ehci_set_interrupt(s, s->usbsts_pending);
+    s->usbsts_pending = 0;
+}
+
+/* Attach or detach a device on root hub */
+
+static void ehci_attach(USBPort *port)
+{
+    EHCIState *s = port->opaque;
+    uint32_t *portsc = &s->portsc[port->index];
+
+    DPRINTF("ehci_attach invoked for index %d, portsc 0x%x, desc %s\n",
+           port->index, *portsc, port->dev->product_desc);
+
+    *portsc |= PORTSC_CONNECT;
+    *portsc |= PORTSC_CSC;
+
+    /*
+     *  If a high speed device is attached then we own this port(indicated
+     *  by zero in the PORTSC_POWNER bit field) so set the status bit
+     *  and set an interrupt if enabled.
+     */
+    if ( !(*portsc & PORTSC_POWNER)) {
+        ehci_set_interrupt(s, USBSTS_PCD);
+    }
+}
+
+static void ehci_detach(USBPort *port)
+{
+    EHCIState *s = port->opaque;
+    uint32_t *portsc = &s->portsc[port->index];
+
+    DPRINTF("ehci_attach invoked for index %d, portsc 0x%x\n",
+           port->index, *portsc);
+
+    *portsc &= ~PORTSC_CONNECT;
+    *portsc |= PORTSC_CSC;
+
+    /*
+     *  If a high speed device is attached then we own this port(indicated
+     *  by zero in the PORTSC_POWNER bit field) so set the status bit
+     *  and set an interrupt if enabled.
+     */
+    if ( !(*portsc & PORTSC_POWNER)) {
+        ehci_set_interrupt(s, USBSTS_PCD);
+    }
+}
+
+/* 4.1 host controller initialization */
+static void ehci_reset(void *opaque)
+{
+    EHCIState *s = opaque;
+    uint8_t *pci_conf;
+    int i;
+
+    pci_conf = s->dev.config;
+
+    memset(&s->mmio[OPREGBASE], 0x00, MMIO_SIZE - OPREGBASE);
+
+    s->usbcmd = NB_MAXINTRATE << USBCMD_ITC_SH;
+    s->usbsts = USBSTS_HALT;
+
+    s->astate = EST_INACTIVE;
+    s->pstate = EST_INACTIVE;
+    s->async_complete = 0;
+    s->isoch_pause = -1;
+    s->attach_poll_counter = 0;
+
+    for(i = 0; i < NB_PORTS; i++) {
+        s->portsc[i] = PORTSC_POWNER | PORTSC_PPOWER;
+
+        if (s->ports[i].dev) {
+            usb_attach(&s->ports[i], s->ports[i].dev);
+        }
+    }
+}
+
+static uint32_t ehci_mem_readb(void *ptr, target_phys_addr_t addr)
+{
+    EHCIState *s = ptr;
+    uint32_t val;
+
+    val = s->mmio[addr];
+
+    return val;
+}
+
+static uint32_t ehci_mem_readw(void *ptr, target_phys_addr_t addr)
+{
+    EHCIState *s = ptr;
+    uint32_t val;
+
+    val = s->mmio[addr] | (s->mmio[addr+1] << 8);
+
+    return val;
+}
+
+static uint32_t ehci_mem_readl(void *ptr, target_phys_addr_t addr)
+{
+    EHCIState *s = ptr;
+    uint32_t val;
+
+    val = s->mmio[addr] | (s->mmio[addr+1] << 8) |
+          (s->mmio[addr+2] << 16) | (s->mmio[addr+3] << 24);
+
+    return val;
+}
+
+static void ehci_mem_writeb(void *ptr, target_phys_addr_t addr, uint32_t val)
+{
+    fprintf(stderr, "EHCI doesn't handle byte writes to MMIO\n");
+    exit(1);
+}
+
+static void ehci_mem_writew(void *ptr, target_phys_addr_t addr, uint32_t val)
+{
+    fprintf(stderr, "EHCI doesn't handle 16-bit writes to MMIO\n");
+    exit(1);
+}
+
+static void handle_port_status_write(EHCIState *s, int port, uint32_t val)
+{
+    uint32_t *portsc = &s->portsc[port];
+    int rwc;
+    USBDevice *dev = s->ports[port].dev;
+
+    DPRINTF("port_status_write: "
+            "PORTSC (port %d) curr %08X new %08X rw-clear %08X rw %08X\n",
+            port, *portsc, val, (val & PORTSC_RWC_MASK), val & PORTSC_RO_MASK);
+
+    rwc = val & PORTSC_RWC_MASK;
+    val &= PORTSC_RO_MASK;
+
+    // handle_read_write_clear(&val, portsc, PORTSC_PEDC | PORTSC_CSC);
+
+    *portsc &= ~rwc;
+
+    if ((val & PORTSC_PRESET) && !(*portsc & PORTSC_PRESET)) {
+        DPRINTF("port_status_write: USBTRAN Port %d reset begin\n", port);
+    }
+
+    if (!(val & PORTSC_PRESET) &&(*portsc & PORTSC_PRESET)) {
+        DPRINTF("port_status_write: USBTRAN Port %d reset done\n", port);
+        usb_attach(&s->ports[port], dev);
+
+        // TODO how to handle reset of ports with no device
+        if (dev) {
+            usb_send_msg(dev, USB_MSG_RESET);
+        }
+
+        if (s->ports[port].dev) {
+            DPRINTF("port_status_write: "
+                    "Device was connected before reset, clearing CSC bit\n");
+            *portsc &= ~PORTSC_CSC;
+        }
+
+        /*  Table 2.16 Set the enable bit(and enable bit change) to indicate
+         *  to SW that this port has a high speed device attached
+         *
+         *  TODO - when to disable?
+         */
+        val |= PORTSC_PED;
+        val |= PORTSC_PEDC;
+    }
+
+    *portsc &= ~PORTSC_RO_MASK;
+    *portsc |= val;
+    DPRINTF("port_status_write: Port %d status set to 0x%08x\n", port, *portsc);
+}
+
+static void ehci_mem_writel(void *ptr, target_phys_addr_t addr, uint32_t val)
+{
+    EHCIState *s = ptr;
+    int i;
+#if EHCI_DEBUG
+    const char *str;
+#endif
+
+    /* Only aligned reads are allowed on OHCI */
+    if (addr & 3) {
+        fprintf(stderr, "usb-ehci: Mis-aligned write to addr 0x"
+                TARGET_FMT_plx "\n", addr);
+        return;
+    }
+
+    if (addr >= PORTSC && addr < PORTSC + 4 * NB_PORTS) {
+        handle_port_status_write(s, (addr-PORTSC)/4, val);
+        return;
+    }
+
+    if (addr < OPREGBASE) {
+        fprintf(stderr, "usb-ehci: write attempt to read-only register"
+                TARGET_FMT_plx "\n", addr);
+        return;
+    }
+
+
+    /* Do any register specific pre-write processing here.  */
+#if EHCI_DEBUG
+    str = addr2str((unsigned) addr);
+#endif
+    switch(addr) {
+    case USBCMD:
+        DPRINTF("ehci_mem_writel: USBCMD val=0x%08X, current cmd=0x%08X\n",
+                val, s->usbcmd);
+
+        if ((val & USBCMD_RUNSTOP) && !(s->usbcmd & USBCMD_RUNSTOP)) {
+            DPRINTF("ehci_mem_writel: %s run, clear halt\n", str);
+            qemu_mod_timer(s->frame_timer, qemu_get_clock_ns(vm_clock));
+            SET_LAST_RUN_CLOCK(s);
+            s->usbsts &= ~USBSTS_HALT;
+        }
+
+        if (!(val & USBCMD_RUNSTOP) && (s->usbcmd & USBCMD_RUNSTOP)) {
+            DPRINTF("                         ** STOP **\n");
+            qemu_del_timer(s->frame_timer);
+            // TODO - should finish out some stuff before setting halt
+            s->usbsts |= USBSTS_HALT;
+        }
+
+        if (val & USBCMD_HCRESET) {
+            DPRINTF("ehci_mem_writel: %s run, resetting\n", str);
+            ehci_reset(s);
+            val &= ~USBCMD_HCRESET;
+        }
+
+        /* not supporting dynamic frame list size at the moment */
+        if ((val & USBCMD_FLS) && !(s->usbcmd & USBCMD_FLS)) {
+            fprintf(stderr, "attempt to set frame list size -- value %d\n",
+                    val & USBCMD_FLS);
+            val &= ~USBCMD_FLS;
+        }
+#if EHCI_DEBUG
+        if ((val & USBCMD_PSE) && !(s->usbcmd & USBCMD_PSE)) {
+            DPRINTF("periodic scheduling enabled\n");
+        }
+        if (!(val & USBCMD_PSE) && (s->usbcmd & USBCMD_PSE)) {
+            DPRINTF("periodic scheduling disabled\n");
+        }
+        if ((val & USBCMD_ASE) && !(s->usbcmd & USBCMD_ASE)) {
+            DPRINTF("asynchronous scheduling enabled\n");
+        }
+        if (!(val & USBCMD_ASE) && (s->usbcmd & USBCMD_ASE)) {
+            DPRINTF("asynchronous scheduling disabled\n");
+        }
+        if ((val & USBCMD_IAAD) && !(s->usbcmd & USBCMD_IAAD)) {
+            DPRINTF("doorbell request received\n");
+        }
+        if ((val & USBCMD_LHCR) && !(s->usbcmd & USBCMD_LHCR)) {
+            DPRINTF("light host controller reset received\n");
+        }
+        if ((val & USBCMD_ITC) != (s->usbcmd & USBCMD_ITC)) {
+            DPRINTF("interrupt threshold control set to %x\n",
+                    (val & USBCMD_ITC)>>USBCMD_ITC_SH);
+        }
+#endif
+        break;
+
+
+    case USBSTS:
+        val &= USBSTS_RO_MASK;              // bits 6 thru 31 are RO
+        DPRINTF("ehci_mem_writel: %s RWC set to 0x%08X\n", str, val);
+
+        val = (s->usbsts &= ~val);         // bits 0 thru 5 are R/WC
+
+        DPRINTF("ehci_mem_writel: %s updating interrupt condition\n", str);
+        ehci_set_interrupt(s, 0);
+        break;
+
+
+    case USBINTR:
+        val &= USBINTR_MASK;
+        DPRINTF("ehci_mem_writel: %s set to 0x%08X\n", str, val);
+        break;
+
+    case FRINDEX:
+        s->sofv = val >> 3;
+        DPRINTF("ehci_mem_writel: %s set to 0x%08X\n", str, val);
+        break;
+
+    case CONFIGFLAG:
+        DPRINTF("ehci_mem_writel: %s set to 0x%08X\n", str, val);
+        val &= 0x1;
+        if (val) {
+            for(i = 0; i < NB_PORTS; i++)
+                s->portsc[i] &= ~PORTSC_POWNER;
+        }
+        break;
+
+    case PERIODICLISTBASE:
+        if ((s->usbcmd & USBCMD_PSE) && (s->usbcmd & USBCMD_RUNSTOP)) {
+            fprintf(stderr,
+              "ehci: PERIODIC list base register set while periodic schedule\n"
+              "      is enabled and HC is enabled\n");
+        }
+        DPRINTF("ehci_mem_writel: P-LIST BASE set to 0x%08X\n", val);
+        break;
+
+    case ASYNCLISTADDR:
+        if ((s->usbcmd & USBCMD_ASE) && (s->usbcmd & USBCMD_RUNSTOP)) {
+            fprintf(stderr,
+              "ehci: ASYNC list address register set while async schedule\n"
+              "      is enabled and HC is enabled\n");
+        }
+        DPRINTF("ehci_mem_writel: A-LIST ADDR set to 0x%08X\n", val);
+        break;
+    }
+
+    *(uint32_t *)(&s->mmio[addr]) = val;
+}
+
+
+// TODO : Put in common header file, duplication from usb-ohci.c
+
+/* Get an array of dwords from main memory */
+static inline int get_dwords(uint32_t addr, uint32_t *buf, int num)
+{
+    int i;
+
+    for(i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
+        cpu_physical_memory_rw(addr,(uint8_t *)buf, sizeof(*buf), 0);
+        *buf = le32_to_cpu(*buf);
+    }
+
+    return 1;
+}
+
+/* Put an array of dwords in to main memory */
+static inline int put_dwords(uint32_t addr, uint32_t *buf, int num)
+{
+    int i;
+
+    for(i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
+        uint32_t tmp = cpu_to_le32(*buf);
+        cpu_physical_memory_rw(addr,(uint8_t *)&tmp, sizeof(tmp), 1);
+    }
+
+    return 1;
+}
+
+// 4.10.2
+
+static int ehci_qh_do_overlay(EHCIState *ehci, EHCIqh *qh, EHCIqtd *qtd)
+{
+    int i;
+    int dtoggle;
+    int ping;
+    int eps;
+    int reload;
+
+    // remember values in fields to preserve in qh after overlay
+
+    dtoggle = qh->token & QTD_TOKEN_DTOGGLE;
+    ping    = qh->token & QTD_TOKEN_PING;
+
+    DPRINTF("setting qh.current from %08X to 0x%08X\n", qh->current_qtd,
+            ehci->qtdaddr);
+    qh->current_qtd = ehci->qtdaddr;
+    qh->next_qtd    = qtd->next;
+    qh->altnext_qtd = qtd->altnext;
+    qh->token       = qtd->token;
+
+
+    eps = get_field(qh->epchar, QH_EPCHAR_EPS);
+    if (eps == EHCI_QH_EPS_HIGH) {
+        qh->token &= ~QTD_TOKEN_PING;
+        qh->token |= ping;
+    }
+
+    reload = get_field(qh->epchar, QH_EPCHAR_RL);
+    set_field(&qh->altnext_qtd, reload, QH_ALTNEXT_NAKCNT);
+
+    for (i = 0; i < 5; i++) {
+        qh->bufptr[i] = qtd->bufptr[i];
+    }
+
+    if (!(qh->epchar & QH_EPCHAR_DTC)) {
+        // preserve QH DT bit
+        qh->token &= ~QTD_TOKEN_DTOGGLE;
+        qh->token |= dtoggle;
+    }
+
+    qh->bufptr[1] &= ~BUFPTR_CPROGMASK_MASK;
+    qh->bufptr[2] &= ~BUFPTR_FRAMETAG_MASK;
+
+    put_dwords(NLPTR_GET(ehci->qhaddr), (uint32_t *) qh, sizeof(EHCIqh) >> 2);
+
+    return 0;
+}
+
+static int ehci_buffer_rw(uint8_t *buffer, EHCIqh *qh, int bytes, int rw)
+{
+    int bufpos = 0;
+    int cpage, offset;
+    uint32_t head;
+    uint32_t tail;
+
+
+    if (!bytes) {
+        return 0;
+    }
+
+    cpage = get_field(qh->token, QTD_TOKEN_CPAGE);
+    if (cpage > 4) {
+        fprintf(stderr, "cpage out of range (%d)\n", cpage);
+        return USB_RET_PROCERR;
+    }
+
+    offset = qh->bufptr[0] & ~QTD_BUFPTR_MASK;
+    DPRINTF("ehci_buffer_rw: %sing %d bytes %08x cpage %d offset %d\n",
+           rw ? "writ" : "read", bytes, qh->bufptr[0], cpage, offset);
+
+    do {
+        /* start and end of this page */
+        head = qh->bufptr[cpage] & QTD_BUFPTR_MASK;
+        tail = head + ~QTD_BUFPTR_MASK + 1;
+        /* add offset into page */
+        head |= offset;
+
+        if (bytes <= (tail - head)) {
+            tail = head + bytes;
+        }
+
+        DPRINTF("DATA %s cpage:%d head:%08X tail:%08X target:%08X\n",
+                rw ? "WRITE" : "READ ", cpage, head, tail, bufpos);
+
+        cpu_physical_memory_rw(head, &buffer[bufpos], tail - head, rw);
+
+        bufpos += (tail - head);
+        bytes -= (tail - head);
+
+        if (bytes > 0) {
+            cpage++;
+            offset = 0;
+        }
+    } while (bytes > 0);
+
+    /* save cpage */
+    set_field(&qh->token, cpage, QTD_TOKEN_CPAGE);
+
+    /* save offset into cpage */
+    offset = tail - head;
+    qh->bufptr[0] &= ~QTD_BUFPTR_MASK;
+    qh->bufptr[0] |= offset;
+
+    return 0;
+}
+
+static void ehci_async_complete_packet(USBDevice *dev, USBPacket *packet)
+{
+    EHCIState *ehci = container_of(packet, EHCIState, usb_packet);
+
+    DPRINTF("Async packet complete\n");
+    ehci->async_complete = 1;
+    ehci->exec_status = packet->len;
+}
+
+static int ehci_execute_complete(EHCIState *ehci, EHCIqh *qh, int ret)
+{
+    int c_err, reload;
+
+    if (ret == USB_RET_ASYNC && !ehci->async_complete) {
+        DPRINTF("not done yet\n");
+        return ret;
+    }
+
+    ehci->async_complete = 0;
+
+    DPRINTF("execute_complete: qhaddr 0x%x, next %x, qtdaddr 0x%x, status %d\n",
+            ehci->qhaddr, qh->next, ehci->qtdaddr, ret);
+
+    if (ret < 0) {
+err:
+        /* TO-DO: put this is in a function that can be invoked below as well */
+        c_err = get_field(qh->token, QTD_TOKEN_CERR);
+        c_err--;
+        set_field(&qh->token, c_err, QTD_TOKEN_CERR);
+
+        switch(ret) {
+        case USB_RET_NODEV:
+            fprintf(stderr, "USB no device\n");
+            break;
+        case USB_RET_STALL:
+            fprintf(stderr, "USB stall\n");
+            qh->token |= QTD_TOKEN_HALT;
+            ehci_record_interrupt(ehci, USBSTS_ERRINT);
+            break;
+        case USB_RET_NAK:
+            /* 4.10.3 */
+            reload = get_field(qh->epchar, QH_EPCHAR_RL);
+            if ((ehci->pid == USB_TOKEN_IN) && reload) {
+                int nakcnt = get_field(qh->altnext_qtd, QH_ALTNEXT_NAKCNT);
+                nakcnt--;
+                set_field(&qh->altnext_qtd, nakcnt, QH_ALTNEXT_NAKCNT);
+            } else if (!reload) {
+                return USB_RET_NAK;
+            }
+            break;
+        case USB_RET_BABBLE:
+            fprintf(stderr, "USB babble TODO\n");
+            qh->token |= QTD_TOKEN_BABBLE;
+            ehci_record_interrupt(ehci, USBSTS_ERRINT);
+            break;
+        default:
+            fprintf(stderr, "USB invalid response %d to handle\n", ret);
+            /* TO-DO: transaction error */
+            ret = USB_RET_PROCERR;
+            break;
+        }
+    } else {
+        // DPRINTF("Short packet condition\n");
+        // TODO check 4.12 for splits
+
+        if ((ret > ehci->tbytes) && (ehci->pid == USB_TOKEN_IN)) {
+            ret = USB_RET_BABBLE;
+            goto err;
+        }
+
+        if (ehci->tbytes && ehci->pid == USB_TOKEN_IN) {
+            if (ehci_buffer_rw(ehci->buffer, qh, ret, 1) != 0) {
+                return USB_RET_PROCERR;
+            }
+            ehci->tbytes -= ret;
+        } else {
+            ehci->tbytes = 0;
+        }
+
+        DPRINTF("updating tbytes to %d\n", ehci->tbytes);
+        set_field(&qh->token, ehci->tbytes, QTD_TOKEN_TBYTES);
+    }
+
+    qh->token ^= QTD_TOKEN_DTOGGLE;
+    qh->token &= ~QTD_TOKEN_ACTIVE;
+
+    if ((ret >= 0) && (qh->token & QTD_TOKEN_IOC)) {
+        ehci_record_interrupt(ehci, USBSTS_INT);
+    }
+
+    return ret;
+}
+
+// 4.10.3
+
+static int ehci_execute(EHCIState *ehci, EHCIqh *qh)
+{
+    USBPort *port;
+    USBDevice *dev;
+    int ret;
+    int i;
+    int endp;
+    int devadr;
+
+    if ( !(qh->token & QTD_TOKEN_ACTIVE)) {
+        fprintf(stderr, "Attempting to execute inactive QH\n");
+        return USB_RET_PROCERR;
+    }
+
+    ehci->tbytes = (qh->token & QTD_TOKEN_TBYTES_MASK) >> QTD_TOKEN_TBYTES_SH;
+    if (ehci->tbytes > BUFF_SIZE) {
+        fprintf(stderr, "Request for more bytes than allowed\n");
+        return USB_RET_PROCERR;
+    }
+
+    ehci->pid = (qh->token & QTD_TOKEN_PID_MASK) >> QTD_TOKEN_PID_SH;
+    switch(ehci->pid) {
+        case 0: ehci->pid = USB_TOKEN_OUT; break;
+        case 1: ehci->pid = USB_TOKEN_IN; break;
+        case 2: ehci->pid = USB_TOKEN_SETUP; break;
+        default: fprintf(stderr, "bad token\n"); break;
+    }
+
+    if ((ehci->tbytes && ehci->pid != USB_TOKEN_IN) &&
+        (ehci_buffer_rw(ehci->buffer, qh, ehci->tbytes, 0) != 0)) {
+        return USB_RET_PROCERR;
+    }
+
+    endp = get_field(qh->epchar, QH_EPCHAR_EP);
+    devadr = get_field(qh->epchar, QH_EPCHAR_DEVADDR);
+
+    ret = USB_RET_NODEV;
+
+    // TO-DO: associating device with ehci port
+    for(i = 0; i < NB_PORTS; i++) {
+        port = &ehci->ports[i];
+        dev = port->dev;
+
+        // TODO sometime we will also need to check if we are the port owner
+
+        if (!(ehci->portsc[i] &(PORTSC_CONNECT))) {
+            DPRINTF("Port %d, no exec, not connected(%08X)\n",
+                    i, ehci->portsc[i]);
+            continue;
+        }
+
+        ehci->usb_packet.pid = ehci->pid;
+        ehci->usb_packet.devaddr = devadr;
+        ehci->usb_packet.devep = endp;
+        ehci->usb_packet.data = ehci->buffer;
+        ehci->usb_packet.len = ehci->tbytes;
+
+        ret = usb_handle_packet(dev, &ehci->usb_packet);
+
+        DPRINTF("submit: qh %x next %x qtd %x pid %x len %d (total %d) endp %x ret %d\n",
+                ehci->qhaddr, qh->next, ehci->qtdaddr, ehci->pid,
+                ehci->usb_packet.len, ehci->tbytes, endp, ret);
+
+        if (ret != USB_RET_NODEV) {
+            break;
+        }
+    }
+
+    if (ret > BUFF_SIZE) {
+        fprintf(stderr, "ret from usb_handle_packet > BUFF_SIZE\n");
+        return USB_RET_PROCERR;
+    }
+
+    if (ret == USB_RET_ASYNC) {
+        ehci->async_complete = 0;
+    }
+
+    return ret;
+}
+
+/*  4.7.2
+ */
+
+static int ehci_process_itd(EHCIState *ehci,
+                            EHCIitd *itd)
+{
+    USBPort *port;
+    USBDevice *dev;
+    int ret;
+    int i, j;
+    int ptr;
+    int pid;
+    int pg;
+    int len;
+    int dir;
+    int devadr;
+    int endp;
+    int maxpkt;
+
+    dir =(itd->bufptr[1] & ITD_BUFPTR_DIRECTION);
+    devadr = get_field(itd->bufptr[0], ITD_BUFPTR_DEVADDR);
+    endp = get_field(itd->bufptr[0], ITD_BUFPTR_EP);
+    maxpkt = get_field(itd->bufptr[1], ITD_BUFPTR_MAXPKT);
+
+    for(i = 0; i < 8; i++) {
+        if (itd->transact[i] & ITD_XACT_ACTIVE) {
+            DPRINTF("ISOCHRONOUS active for frame %d, interval %d\n",
+                    ehci->frindex >> 3, i);
+
+            pg = get_field(itd->transact[i], ITD_XACT_PGSEL);
+            ptr = (itd->bufptr[pg] & ITD_BUFPTR_MASK) |
+                (itd->transact[i] & ITD_XACT_OFFSET_MASK);
+            len = get_field(itd->transact[i], ITD_XACT_LENGTH);
+
+            if (len > BUFF_SIZE) {
+                return USB_RET_PROCERR;
+            }
+
+            DPRINTF("ISOCH: buffer %08X len %d\n", ptr, len);
+
+            if (!dir) {
+                cpu_physical_memory_rw(ptr, &ehci->buffer[0], len, 0);
+                pid = USB_TOKEN_OUT;
+            } else
+                pid = USB_TOKEN_IN;
+
+            ret = USB_RET_NODEV;
+
+            for (j = 0; j < NB_PORTS; j++) {
+                port = &ehci->ports[j];
+                dev = port->dev;
+
+                // TODO sometime we will also need to check if we are the port owner
+
+                if (!(ehci->portsc[j] &(PORTSC_CONNECT))) {
+                    DPRINTF("Port %d, no exec, not connected(%08X)\n",
+                            j, ehci->portsc[j]);
+                    continue;
+                }
+
+                ehci->usb_packet.pid = ehci->pid;
+                ehci->usb_packet.devaddr = devadr;
+                ehci->usb_packet.devep = endp;
+                ehci->usb_packet.data = ehci->buffer;
+                ehci->usb_packet.len = len;
+
+                DPRINTF("calling usb_handle_packet\n");
+                ret = usb_handle_packet(dev, &ehci->usb_packet);
+
+                if (ret != USB_RET_NODEV) {
+                    break;
+                }
+            }
+
+            /*  In isoch, there is no facility to indicate a NAK so let's
+             *  instead just complete a zero-byte transaction.  Setting
+             *  DBERR seems too draconian.
+             */
+
+            if (ret == USB_RET_NAK) {
+                if (ehci->isoch_pause > 0) {
+                    DPRINTF("ISOCH: received a NAK but paused so returning\n");
+                    ehci->isoch_pause--;
+                    return 0;
+                } else if (ehci->isoch_pause == -1) {
+                    DPRINTF("ISOCH: recv NAK & isoch pause inactive, setting\n");
+                    // Pause frindex for up to 50 msec waiting for data from
+                    // remote
+                    ehci->isoch_pause = 50;
+                    return 0;
+                } else {
+                    DPRINTF("ISOCH: isoch pause timeout! return 0\n");
+                    ret = 0;
+                }
+            } else {
+                DPRINTF("ISOCH: received ACK, clearing pause\n");
+                ehci->isoch_pause = -1;
+            }
+
+            if (ret >= 0) {
+                itd->transact[i] &= ~ITD_XACT_ACTIVE;
+
+                if (itd->transact[i] & ITD_XACT_IOC) {
+                    ehci_record_interrupt(ehci, USBSTS_INT);
+                }
+            }
+
+            if (ret >= 0 && dir) {
+                cpu_physical_memory_rw(ptr, &ehci->buffer[0], len, 1);
+
+                if (ret != len) {
+                    DPRINTF("ISOCH IN expected %d, got %d\n",
+                            len, ret);
+                    set_field(&itd->transact[i], ret, ITD_XACT_LENGTH);
+                }
+            }
+        }
+    }
+    return 0;
+}
+
+/*  This state is the entry point for asynchronous schedule
+ *  processing.  Entry here consitutes a EHCI start event state (4.8.5)
+ */
+static int ehci_state_waitlisthead(EHCIState *ehci,  int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    int i = 0;
+    int again = 0;
+    uint32_t entry = ehci->asynclistaddr;
+
+    /* set reclamation flag at start event (4.8.6) */
+    if (async) {
+        ehci->usbsts |= USBSTS_REC;
+    }
+
+    /*  Find the head of the list (4.9.1.1) */
+    for(i = 0; i < MAX_QH; i++) {
+        get_dwords(NLPTR_GET(entry), (uint32_t *) qh, sizeof(EHCIqh) >> 2);
+
+        if (qh->epchar & QH_EPCHAR_H) {
+            DPRINTF_ST("WAITLISTHEAD: QH %08X is the HEAD of the list\n",
+                       entry);
+            if (async) {
+                entry |= (NLPTR_TYPE_QH << 1);
+            }
+
+            ehci->fetch_addr = entry;
+            *state = EST_FETCHENTRY;
+            again = 1;
+            goto out;
+        }
+
+        DPRINTF_ST("WAITLISTHEAD: QH %08X is NOT the HEAD of the list\n",
+                   entry);
+        entry = qh->next;
+        if (entry == ehci->asynclistaddr) {
+            DPRINTF("WAITLISTHEAD: reached beginning of QH list\n");
+            break;
+        }
+    }
+
+    /* no head found for list. */
+
+    *state = EST_ACTIVE;
+
+out:
+    return again;
+}
+
+
+/*  This state is the entry point for periodic schedule processing as
+ *  well as being a continuation state for async processing.
+ */
+static int ehci_state_fetchentry(EHCIState *ehci, int async, int *state)
+{
+    int again = 0;
+    uint32_t entry = ehci->fetch_addr;
+
+#if EHCI_DEBUG == 0
+    if (qemu_get_clock_ns(vm_clock) / 1000 >= ehci->frame_end_usec) {
+        if (async) {
+            DPRINTF("FETCHENTRY: FRAME timer elapsed, exit state machine\n");
+            goto out;
+        } else {
+            DPRINTF("FETCHENTRY: WARNING "
+                    "- frame timer elapsed during periodic\n");
+        }
+    }
+#endif
+    if (entry < 0x1000) {
+        DPRINTF("fetchentry: entry invalid (0x%08x)\n", entry);
+        *state = EST_ACTIVE;
+        goto out;
+    }
+
+    /* section 4.8, only QH in async schedule */
+    if (async && (NLPTR_TYPE_GET(entry) != NLPTR_TYPE_QH)) {
+        fprintf(stderr, "non queue head request in async schedule\n");
+        return -1;
+    }
+
+    switch (NLPTR_TYPE_GET(entry)) {
+    case NLPTR_TYPE_QH:
+        DPRINTF_ST("FETCHENTRY: entry %X is a Queue Head\n", entry);
+        *state = EST_FETCHQH;
+        ehci->qhaddr = entry;
+        again = 1;
+        break;
+
+    case NLPTR_TYPE_ITD:
+        DPRINTF_ST("FETCHENTRY: entry %X is an ITD\n", entry);
+        *state = EST_FETCHITD;
+        ehci->itdaddr = entry;
+        again = 1;
+        break;
+
+    default:
+        // TODO: handle siTD and FSTN types
+        fprintf(stderr, "FETCHENTRY: entry at %X is of type %d "
+                "which is not supported yet\n", entry, NLPTR_TYPE_GET(entry));
+        return -1;
+    }
+
+out:
+    return again;
+}
+
+static int ehci_state_fetchqh(EHCIState *ehci, int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    int reload;
+    int again = 0;
+
+    get_dwords(NLPTR_GET(ehci->qhaddr), (uint32_t *) qh, sizeof(EHCIqh) >> 2);
+
+    if (async && (qh->epchar & QH_EPCHAR_H)) {
+
+        /*  EHCI spec version 1.0 Section 4.8.3 & 4.10.1 */
+        if (ehci->usbsts & USBSTS_REC) {
+            ehci->usbsts &= ~USBSTS_REC;
+        } else {
+            DPRINTF("FETCHQH:  QH 0x%08x. H-bit set, reclamation status reset"
+                       " - done processing\n", ehci->qhaddr);
+            *state = EST_ACTIVE;
+            goto out;
+        }
+    }
+
+#if EHCI_DEBUG
+    if (ehci->qhaddr != qh->next) {
+    DPRINTF("FETCHQH:  QH 0x%08x (h %x halt %x active %x) next 0x%08x\n",
+               ehci->qhaddr,
+               qh->epchar & QH_EPCHAR_H,
+               qh->token & QTD_TOKEN_HALT,
+               qh->token & QTD_TOKEN_ACTIVE,
+               qh->next);
+    }
+#endif
+
+    reload = get_field(qh->epchar, QH_EPCHAR_RL);
+    if (reload) {
+        DPRINTF_ST("FETCHQH: reloading nakcnt to %d\n", reload);
+        set_field(&qh->altnext_qtd, reload, QH_ALTNEXT_NAKCNT);
+    }
+
+    if (qh->token & QTD_TOKEN_HALT) {
+        DPRINTF_ST("FETCHQH: QH Halted, go horizontal\n");
+        *state = EST_HORIZONTALQH;
+        again = 1;
+
+    } else if ((qh->token & QTD_TOKEN_ACTIVE) && (qh->current_qtd > 0x1000)) {
+        DPRINTF_ST("FETCHQH: Active, !Halt, execute - fetch qTD\n");
+        ehci->qtdaddr = qh->current_qtd;
+        *state = EST_FETCHQTD;
+        again = 1;
+
+    } else {
+        /*  EHCI spec version 1.0 Section 4.10.2 */
+        DPRINTF_ST("FETCHQH: !Active, !Halt, advance queue\n");
+        *state = EST_ADVANCEQUEUE;
+        again = 1;
+    }
+
+out:
+    return again;
+}
+
+static int ehci_state_fetchitd(EHCIState *ehci, int async, int *state)
+{
+    EHCIitd itd;
+
+    get_dwords(NLPTR_GET(ehci->itdaddr),(uint32_t *) &itd,
+               sizeof(EHCIitd) >> 2);
+    DPRINTF_ST("FETCHITD: Fetched ITD at address %08X " "(next is %08X)\n",
+               ehci->itdaddr, itd.next);
+
+    if (ehci_process_itd(ehci, &itd) != 0) {
+        return -1;
+    }
+
+    put_dwords(NLPTR_GET(ehci->itdaddr), (uint32_t *) &itd,
+                sizeof(EHCIitd) >> 2);
+    ehci->fetch_addr = itd.next;
+    *state = EST_FETCHENTRY;
+
+    return 1;
+}
+
+/* Section 4.10.2 - paragraph 3 */
+static int ehci_state_advqueue(EHCIState *ehci, int async, int *state)
+{
+#if 0
+    /* TO-DO: 4.10.2 - paragraph 2
+     * if I-bit is set to 1 and QH is not active
+     * go to horizontal QH
+     */
+    if (I-bit set) {
+        *state = EST_HORIZONTALQH;
+        goto out;
+    }
+#endif
+
+    /*
+     * want data and alt-next qTD is valid
+     */
+    if (((ehci->qh.token & QTD_TOKEN_TBYTES_MASK) != 0) &&
+        (ehci->qh.altnext_qtd > 0x1000) &&
+        (NLPTR_TBIT(ehci->qh.altnext_qtd) == 0)) {
+        DPRINTF_ST("ADVQUEUE: goto alt next qTD. "
+                   "curr 0x%08x next 0x%08x alt 0x%08x (next qh %x)\n",
+                   ehci->qh.current_qtd, ehci->qh.altnext_qtd,
+                   ehci->qh.next_qtd, ehci->qh.next);
+        ehci->qtdaddr = ehci->qh.altnext_qtd;
+        *state = EST_FETCHQTD;
+
+    /*
+     *  next qTD is valid
+     */
+    } else if ((ehci->qh.next_qtd > 0x1000) &&
+               (NLPTR_TBIT(ehci->qh.next_qtd) == 0)) {
+        DPRINTF_ST("ADVQUEUE: next qTD. "
+                   "curr 0x%08x next 0x%08x alt 0x%08x (next qh %x)\n",
+                   ehci->qh.current_qtd, ehci->qh.altnext_qtd,
+                   ehci->qh.next_qtd, ehci->qh.next);
+        ehci->qtdaddr = ehci->qh.next_qtd;
+        *state = EST_FETCHQTD;
+
+    /*
+     *  no valid qTD, try next QH
+     */
+    } else {
+        DPRINTF_ST("ADVQUEUE: go to horizontal QH\n");
+        *state = EST_HORIZONTALQH;
+    }
+
+    return 1;
+}
+
+/* Section 4.10.2 - paragraph 4 */
+static int ehci_state_fetchqtd(EHCIState *ehci, int async, int *state)
+{
+    EHCIqtd *qtd = &ehci->qtd;
+    int again = 0;
+
+    get_dwords(NLPTR_GET(ehci->qtdaddr),(uint32_t *) qtd, sizeof(EHCIqtd) >> 2);
+
+    if (qtd->token & QTD_TOKEN_ACTIVE) {
+        *state = EST_EXECUTE;
+        again = 1;
+    } else {
+        *state = EST_HORIZONTALQH;
+        again = 1;
+    }
+
+    return again;
+}
+
+static int ehci_state_horizqh(EHCIState *ehci, int async, int *state)
+{
+    int again = 0;
+
+    if (ehci->fetch_addr != ehci->qh.next) {
+        ehci->fetch_addr = ehci->qh.next;
+        *state = EST_FETCHENTRY;
+        again = 1;
+    } else {
+        *state = EST_ACTIVE;
+    }
+
+    return again;
+}
+
+static int ehci_state_execute(EHCIState *ehci, int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    EHCIqtd *qtd = &ehci->qtd;
+    int again = 0;
+    int reload, nakcnt;
+    int smask;
+
+    if (async) {
+        DPRINTF_ST(">>>>> ASYNC STATE MACHINE execute QH 0x%08x, QTD 0x%08x\n",
+                  ehci->qhaddr, ehci->qtdaddr);
+    } else {
+        DPRINTF_ST(">>>>> PERIODIC STATE MACHINE execute\n");
+    }
+
+    if (ehci_qh_do_overlay(ehci, qh, qtd) != 0) {
+        return -1;
+    }
+
+    smask = get_field(qh->epcap, QH_EPCAP_SMASK);
+
+    if (!smask) {
+        reload = get_field(qh->epchar, QH_EPCHAR_RL);
+        nakcnt = get_field(qh->altnext_qtd, QH_ALTNEXT_NAKCNT);
+        if (reload && !nakcnt) {
+            DPRINTF_ST("EXECUTE: RL != 0 but NakCnt == 0 -- no execute\n");
+            *state = EST_HORIZONTALQH;
+            again = 1;
+            goto out;
+        }
+    }
+
+    // TODO verify enough time remains in the uframe as in 4.4.1.1
+    // TODO write back ptr to async list when done or out of time
+    // TODO Windows does not seem to ever set the MULT field
+
+    if (!async) {
+        int transactCtr = get_field(qh->epcap, QH_EPCAP_MULT);
+        if (!transactCtr) {
+            DPRINTF("ZERO transactctr for int qh, go HORIZ\n");
+            *state = EST_HORIZONTALQH;
+            again = 1;
+            goto out;
+        }
+    }
+
+    if (async) {
+        ehci->usbsts |= USBSTS_REC;
+    }
+
+    ehci->exec_status = ehci_execute(ehci, qh);
+    if (ehci->exec_status == USB_RET_PROCERR) {
+        again = -1;
+        goto out;
+    }
+    *state = EST_EXECUTING;
+
+    if (ehci->exec_status != USB_RET_ASYNC) {
+        again = 1;
+    }
+
+out:
+    return again;
+}
+
+static int ehci_state_executing(EHCIState *ehci, int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    int again = 0;
+    int reload, nakcnt;
+
+    ehci->exec_status = ehci_execute_complete(ehci, qh, ehci->exec_status);
+    if (ehci->exec_status == USB_RET_ASYNC) {
+        goto out;
+    }
+    if (ehci->exec_status == USB_RET_PROCERR) {
+        again = -1;
+        goto out;
+    }
+
+    // 4.10.3
+    if (!async) {
+        int transactCtr = get_field(qh->epcap, QH_EPCAP_MULT);
+        transactCtr--;
+        set_field(&qh->epcap, transactCtr, QH_EPCAP_MULT);
+        // 4.10.3, bottom of page 82, should exit this state when transaction
+        // counter decrements to 0
+    }
+
+
+    reload = get_field(qh->epchar, QH_EPCHAR_RL);
+    if (reload) {
+        nakcnt = get_field(qh->altnext_qtd, QH_ALTNEXT_NAKCNT);
+        if (ehci->exec_status == USB_RET_NAK) {
+            if (nakcnt) {
+                nakcnt--;
+            }
+            DPRINTF_ST("EXECUTING: Nak occured and RL != 0, dec NakCnt to %d\n",
+                    nakcnt);
+        } else {
+            nakcnt = reload;
+            DPRINTF_ST("EXECUTING: Nak didn't occur, reloading to %d\n",
+                       nakcnt);
+        }
+        set_field(&qh->altnext_qtd, nakcnt, QH_ALTNEXT_NAKCNT);
+    }
+
+    /*
+     *  Write the qh back to guest physical memory.  This step isn't
+     *  in the EHCI spec but we need to do it since we don't share
+     *  physical memory with our guest VM.
+     */
+
+    DPRINTF("EXECUTING: write QH to VM memory: qhaddr 0x%x, next 0x%x\n",
+              ehci->qhaddr, qh->next);
+    put_dwords(NLPTR_GET(ehci->qhaddr), (uint32_t *) qh, sizeof(EHCIqh) >> 2);
+
+    /* 4.10.5 */
+    if ((ehci->exec_status == USB_RET_NAK) || (qh->token & QTD_TOKEN_ACTIVE)) {
+        *state = EST_HORIZONTALQH;
+    } else {
+        *state = EST_WRITEBACK;
+    }
+
+    again = 1;
+
+out:
+    return again;
+}
+
+
+static int ehci_state_writeback(EHCIState *ehci, int async, int *state)
+{
+    EHCIqh *qh = &ehci->qh;
+    int again = 0;
+
+    /*  Write back the QTD from the QH area */
+    DPRINTF_ST("WRITEBACK: write QTD to VM memory\n");
+    put_dwords(NLPTR_GET(ehci->qtdaddr),(uint32_t *) &qh->next_qtd,
+                sizeof(EHCIqtd) >> 2);
+
+    /* TODO confirm next state.  For now, keep going if async
+     * but stop after one qtd if periodic
+     */
+    //if (async) {
+        *state = EST_ADVANCEQUEUE;
+        again = 1;
+    //} else {
+    //    *state = EST_ACTIVE;
+    //}
+    return again;
+}
+
+/*
+ * This is the state machine that is common to both async and periodic
+ */
+
+static int ehci_advance_state(EHCIState *ehci,
+                              int async,
+                              int state)
+{
+    int again;
+    int iter = 0;
+
+    do {
+        if (state == EST_FETCHQH) {
+            iter++;
+            /* if we are roaming a lot of QH without executing a qTD
+             * something is wrong with the linked list. TO-DO: why is
+             * this hack needed?
+             */
+            if (iter > MAX_ITERATIONS) {
+                DPRINTF("\n*** advance_state: bailing on MAX ITERATIONS***\n");
+                state = EST_ACTIVE;
+                break;
+            }
+        }
+        switch(state) {
+        case EST_WAITLISTHEAD:
+            again = ehci_state_waitlisthead(ehci, async, &state);
+            break;
+
+        case EST_FETCHENTRY:
+            again = ehci_state_fetchentry(ehci, async, &state);
+            break;
+
+        case EST_FETCHQH:
+            again = ehci_state_fetchqh(ehci, async, &state);
+            break;
+
+        case EST_FETCHITD:
+            again = ehci_state_fetchitd(ehci, async, &state);
+            break;
+
+        case EST_ADVANCEQUEUE:
+            again = ehci_state_advqueue(ehci, async, &state);
+            break;
+
+        case EST_FETCHQTD:
+            again = ehci_state_fetchqtd(ehci, async, &state);
+            break;
+
+        case EST_HORIZONTALQH:
+            again = ehci_state_horizqh(ehci, async, &state);
+            break;
+
+        case EST_EXECUTE:
+            iter = 0;
+            again = ehci_state_execute(ehci, async, &state);
+            break;
+
+        case EST_EXECUTING:
+            again = ehci_state_executing(ehci, async, &state);
+            break;
+
+        case EST_WRITEBACK:
+            again = ehci_state_writeback(ehci, async, &state);
+            break;
+
+        default:
+            fprintf(stderr, "Bad state!\n");
+            again = -1;
+            break;
+        }
+
+        if (again < 0) {
+            fprintf(stderr, "processing error - resetting ehci HC\n");
+            ehci_reset(ehci);
+            again = 0;
+        }
+    }
+    while (again);
+
+    ehci_commit_interrupt(ehci);
+    return state;
+}
+
+static void ehci_advance_async_state(EHCIState *ehci)
+{
+    EHCIqh qh;
+    int state = ehci->astate;
+
+    switch(state) {
+    case EST_INACTIVE:
+        if (!(ehci->usbcmd & USBCMD_ASE)) {
+            break;
+        }
+        ehci->usbsts |= USBSTS_ASS;
+        ehci->astate = EST_ACTIVE;
+        // No break, fall through to ACTIVE
+
+    case EST_ACTIVE:
+        if ( !(ehci->usbcmd & USBCMD_ASE)) {
+            ehci->usbsts &= ~USBSTS_ASS;
+            ehci->astate = EST_INACTIVE;
+            break;
+        }
+
+        /* If the doorbell is set, the guest wants to make a change to the
+         * schedule. The host controller needs to release cached data.
+         * (section 4.8.2)
+         */
+        if (ehci->usbcmd & USBCMD_IAAD) {
+            DPRINTF("ASYNC: doorbell request acknowledged\n");
+            ehci->usbcmd &= ~USBCMD_IAAD;
+            ehci_set_interrupt(ehci, USBSTS_IAA);
+            break;
+        }
+
+        /* make sure guest has acknowledged */
+        /* TO-DO: is this really needed? */
+        if (ehci->usbsts & USBSTS_IAA) {
+            DPRINTF("IAA status bit still set.\n");
+            break;
+        }
+
+        DPRINTF_ST("ASYNC: waiting for listhead, starting at %08x\n",
+                ehci->asynclistaddr);
+        /* check that address register has been set */
+        if (ehci->asynclistaddr == 0) {
+            break;
+        }
+
+        state = EST_WAITLISTHEAD;
+        /* fall through */
+
+    case EST_FETCHENTRY:
+        /* fall through */
+
+    case EST_EXECUTING:
+        get_dwords(NLPTR_GET(ehci->qhaddr), (uint32_t *) &qh,
+                   sizeof(EHCIqh) >> 2);
+        ehci->astate = ehci_advance_state(ehci, 1, state);
+        break;
+
+    default:
+        /* this should only be due to a developer mistake */
+        fprintf(stderr, "ehci: Bad asynchronous state %d. "
+                "Resetting to active\n", ehci->astate);
+        ehci->astate = EST_ACTIVE;
+    }
+}
+
+static void ehci_advance_periodic_state(EHCIState *ehci)
+{
+    uint32_t entry;
+    uint32_t list;
+
+    // 4.6
+
+    switch(ehci->pstate) {
+    case EST_INACTIVE:
+        if ( !(ehci->frindex & 7) && (ehci->usbcmd & USBCMD_PSE)) {
+            DPRINTF("PERIODIC going active\n");
+            ehci->usbsts |= USBSTS_PSS;
+            ehci->pstate = EST_ACTIVE;
+            // No break, fall through to ACTIVE
+        } else
+            break;
+
+    case EST_ACTIVE:
+        if ( !(ehci->frindex & 7) && !(ehci->usbcmd & USBCMD_PSE)) {
+            DPRINTF("PERIODIC going inactive\n");
+            ehci->usbsts &= ~USBSTS_PSS;
+            ehci->pstate = EST_INACTIVE;
+            break;
+        }
+
+        list = ehci->periodiclistbase & 0xfffff000;
+        /* check that register has been set */
+        if (list == 0) {
+            break;
+        }
+        list |= ((ehci->frindex & 0x1ff8) >> 1);
+
+        cpu_physical_memory_rw(list, (uint8_t *) &entry, sizeof entry, 0);
+        entry = le32_to_cpu(entry);
+
+        DPRINTF("PERIODIC state adv fr=%d.  [%08X] -> %08X\n",
+                ehci->frindex / 8, list, entry);
+        ehci->fetch_addr = entry;
+        ehci->pstate = ehci_advance_state(ehci, 0, EST_FETCHENTRY);
+        break;
+
+    case EST_EXECUTING:
+        DPRINTF("PERIODIC state adv for executing\n");
+        ehci->pstate = ehci_advance_state(ehci, 0, EST_EXECUTING);
+        break;
+
+    default:
+        /* this should only be due to a developer mistake */
+        fprintf(stderr, "ehci: Bad periodic state %d. "
+                "Resetting to active\n", ehci->pstate);
+        ehci->pstate = EST_ACTIVE;
+    }
+}
+
+static void ehci_frame_timer(void *opaque)
+{
+    EHCIState *ehci = opaque;
+    int64_t expire_time, t_now;
+    int usec_elapsed;
+    int frames;
+    int usec_now;
+    int i;
+    int skipped_frames = 0;
+
+
+    t_now = qemu_get_clock_ns(vm_clock);
+    expire_time = t_now + (get_ticks_per_sec() / FRAME_TIMER_FREQ);
+    if (expire_time == t_now) {
+        expire_time++;
+    }
+
+    usec_now = t_now / 1000;
+    usec_elapsed = usec_now - ehci->last_run_usec;
+    frames = usec_elapsed / FRAME_TIMER_USEC;
+    ehci->frame_end_usec = usec_now + FRAME_TIMER_USEC - 10;
+
+    for (i = 0; i < frames; i++) {
+        if ( !(ehci->usbsts & USBSTS_HALT)) {
+            if (ehci->isoch_pause <= 0) {
+                ehci->frindex += 8;
+            }
+
+            if (ehci->frindex > 0x00001fff) {
+                ehci->frindex = 0;
+                ehci_set_interrupt(ehci, USBSTS_FLR);
+            }
+
+            ehci->sofv = (ehci->frindex - 1) >> 3;
+            ehci->sofv &= 0x000003ff;
+        }
+
+        if (frames - i > 10) {
+            skipped_frames++;
+        } else {
+            // TODO could this cause periodic frames to get skipped if async
+            // active?
+            if (ehci->astate != EST_EXECUTING) {
+                ehci_advance_periodic_state(ehci);
+            }
+        }
+
+        ehci->last_run_usec += FRAME_TIMER_USEC;
+    }
+
+#if 0
+    if (skipped_frames) {
+        DPRINTF("WARNING - EHCI skipped %d frames\n", skipped_frames);
+    }
+#endif
+
+    /*  Async is not inside loop since it executes everything it can once
+     *  called
+     */
+    if (ehci->pstate != EST_EXECUTING) {
+        ehci_advance_async_state(ehci);
+    }
+
+    qemu_mod_timer(ehci->frame_timer, expire_time);
+}
+
+static CPUReadMemoryFunc *ehci_readfn[3]={
+    ehci_mem_readb,
+    ehci_mem_readw,
+    ehci_mem_readl
+};
+
+static CPUWriteMemoryFunc *ehci_writefn[3]={
+    ehci_mem_writeb,
+    ehci_mem_writew,
+    ehci_mem_writel
+};
+
+static void ehci_map(PCIDevice *pci_dev, int region_num,
+                     pcibus_t addr, pcibus_t size, int type)
+{
+    EHCIState *s =(EHCIState *)pci_dev;
+
+    DPRINTF("ehci_map: region %d, addr %08" PRIx64 ", size %" PRId64 ", s->mem %08X\n",
+            region_num, addr, size, s->mem);
+    s->mem_base = addr;
+    cpu_register_physical_memory(addr, size, s->mem);
+}
+
+static int usb_ehci_initfn(PCIDevice *dev);
+
+static USBPortOps ehci_port_ops = {
+    .attach = ehci_attach,
+    .detach = ehci_detach,
+    .complete = ehci_async_complete_packet,
+};
+
+static PCIDeviceInfo ehci_info = {
+    .qdev.name    = "usb-ehci",
+    .qdev.size    = sizeof(EHCIState),
+    .init         = usb_ehci_initfn,
+};
+
+static int usb_ehci_initfn(PCIDevice *dev)
+{
+    EHCIState *s = DO_UPCAST(EHCIState, dev, dev);
+    uint8_t *pci_conf = s->dev.config;
+    int i;
+
+    pci_config_set_vendor_id(pci_conf, PCI_VENDOR_ID_INTEL);
+    pci_config_set_device_id(pci_conf, PCI_DEVICE_ID_INTEL_82801D);
+    pci_set_byte(&pci_conf[PCI_REVISION_ID], 0x10);
+    pci_set_byte(&pci_conf[PCI_CLASS_PROG], 0x20);
+    pci_config_set_class(pci_conf, PCI_CLASS_SERIAL_USB);
+    pci_set_byte(&pci_conf[PCI_HEADER_TYPE], PCI_HEADER_TYPE_NORMAL);
+
+    /* capabilities pointer */
+    pci_set_byte(&pci_conf[PCI_CAPABILITY_LIST], 0x00);
+    //pci_set_byte(&pci_conf[PCI_CAPABILITY_LIST], 0x50);
+
+    pci_set_byte(&pci_conf[PCI_INTERRUPT_PIN], 4); // interrupt pin 3
+    pci_set_byte(&pci_conf[PCI_MIN_GNT], 0);
+    pci_set_byte(&pci_conf[PCI_MAX_LAT], 0);
+
+    // pci_conf[0x50] = 0x01; // power management caps
+
+    pci_set_byte(&pci_conf[0x60], 0x20);  // spec release number (2.1.4)
+    pci_set_byte(&pci_conf[0x61], 0x20);  // frame length adjustment (2.1.5)
+    pci_set_word(&pci_conf[0x62], 0x00);  // port wake up capability (2.1.6)
+
+    pci_conf[0x64] = 0x00;
+    pci_conf[0x65] = 0x00;
+    pci_conf[0x66] = 0x00;
+    pci_conf[0x67] = 0x00;
+    pci_conf[0x68] = 0x01;
+    pci_conf[0x69] = 0x00;
+    pci_conf[0x6a] = 0x00;
+    pci_conf[0x6b] = 0x00;  // USBLEGSUP
+    pci_conf[0x6c] = 0x00;
+    pci_conf[0x6d] = 0x00;
+    pci_conf[0x6e] = 0x00;
+    pci_conf[0x6f] = 0xc0;  // USBLEFCTLSTS
+
+    // 2.2 host controller interface version
+    s->mmio[0x00] = (uint8_t) OPREGBASE;
+    s->mmio[0x01] = 0x00;
+    s->mmio[0x02] = 0x00;
+    s->mmio[0x03] = 0x01;        // HC version
+    s->mmio[0x04] = NB_PORTS;    // Number of downstream ports
+    s->mmio[0x05] = 0x00;        // No companion ports at present
+    s->mmio[0x06] = 0x00;
+    s->mmio[0x07] = 0x00;
+    s->mmio[0x08] = 0x80;        // We can cache whole frame, not 64-bit capable
+    s->mmio[0x09] = 0x68;        // EECP
+    s->mmio[0x0a] = 0x00;
+    s->mmio[0x0b] = 0x00;
+
+    s->irq = s->dev.irq[3];
+
+    usb_bus_new(&s->bus, &s->dev.qdev);
+    for(i = 0; i < NB_PORTS; i++) {
+        usb_register_port(&s->bus, &s->ports[i], s, i, &ehci_port_ops,
+                          USB_SPEED_MASK_HIGH);
+        usb_port_location(&s->ports[i], NULL, i+1);
+        s->ports[i].dev = 0;
+    }
+
+    s->frame_timer = qemu_new_timer_ns(vm_clock, ehci_frame_timer, s);
+
+    qemu_register_reset(ehci_reset, s);
+
+    s->mem = cpu_register_io_memory(ehci_readfn, ehci_writefn, s,
+                                    DEVICE_LITTLE_ENDIAN);
+
+    pci_register_bar(&s->dev, 0, MMIO_SIZE, PCI_BASE_ADDRESS_SPACE_MEMORY,
+                                                            ehci_map);
+
+    fprintf(stderr, "*** EHCI support is under development ***\n");
+
+    return 0;
+}
+
+static void ehci_register(void)
+{
+    pci_qdev_register(&ehci_info);
+}
+device_init(ehci_register);
+
+/*
+ * vim: expandtab ts=4
+ */
diff --git a/hw/usb-hid.c b/hw/usb-hid.c
index 89c293c..53b261c 100644
--- a/hw/usb-hid.c
+++ b/hw/usb-hid.c
@@ -211,6 +211,7 @@ static const USBDescDevice desc_device_mouse = {
             .iConfiguration        = STR_CONFIG_MOUSE,
             .bmAttributes          = 0xa0,
             .bMaxPower             = 50,
+            .nif = 1,
             .ifs = &desc_iface_mouse,
         },
     },
@@ -227,6 +228,7 @@ static const USBDescDevice desc_device_tablet = {
             .iConfiguration        = STR_CONFIG_TABLET,
             .bmAttributes          = 0xa0,
             .bMaxPower             = 50,
+            .nif = 1,
             .ifs = &desc_iface_tablet,
         },
     },
@@ -243,6 +245,7 @@ static const USBDescDevice desc_device_keyboard = {
             .iConfiguration        = STR_CONFIG_KEYBOARD,
             .bmAttributes          = 0xa0,
             .bMaxPower             = 50,
+            .nif = 1,
             .ifs = &desc_iface_keyboard,
         },
     },
@@ -724,13 +727,13 @@ static void usb_hid_set_next_idle(USBHIDState *s, int64_t curtime)
     s->next_idle_clock = curtime + (get_ticks_per_sec() * s->idle * 4) / 1000;
 }
 
-static int usb_hid_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int usb_hid_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBHIDState *s = (USBHIDState *)dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
diff --git a/hw/usb-hub.c b/hw/usb-hub.c
index e0588f8..6e2a358 100644
--- a/hw/usb-hub.c
+++ b/hw/usb-hub.c
@@ -119,6 +119,7 @@ static const USBDescDevice desc_device_hub = {
             .bNumInterfaces        = 1,
             .bConfigurationValue   = 1,
             .bmAttributes          = 0xe0,
+            .nif = 1,
             .ifs = &desc_iface_hub,
         },
     },
@@ -284,13 +285,13 @@ static void usb_hub_handle_reset(USBDevice *dev)
     /* XXX: do it */
 }
 
-static int usb_hub_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int usb_hub_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBHubState *s = (USBHubState *)dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
@@ -494,7 +495,7 @@ static int usb_hub_broadcast_packet(USBHubState *s, USBPacket *p)
         port = &s->ports[i];
         dev = port->port.dev;
         if (dev && (port->wPortStatus & PORT_STAT_ENABLE)) {
-            ret = dev->info->handle_packet(dev, p);
+            ret = usb_handle_packet(dev, p);
             if (ret != USB_RET_NODEV) {
                 return ret;
             }
diff --git a/hw/usb-msd.c b/hw/usb-msd.c
index bd1c3a4..141da2c 100644
--- a/hw/usb-msd.c
+++ b/hw/usb-msd.c
@@ -119,6 +119,7 @@ static const USBDescDevice desc_device_full = {
             .bConfigurationValue   = 1,
             .iConfiguration        = STR_CONFIG_FULL,
             .bmAttributes          = 0xc0,
+            .nif = 1,
             .ifs = &desc_iface_full,
         },
     },
@@ -153,6 +154,7 @@ static const USBDescDevice desc_device_high = {
             .bConfigurationValue   = 1,
             .iConfiguration        = STR_CONFIG_HIGH,
             .bmAttributes          = 0xc0,
+            .nif = 1,
             .ifs = &desc_iface_high,
         },
     },
@@ -251,7 +253,7 @@ static void usb_msd_command_complete(SCSIBus *bus, int reason, uint32_t tag,
     s->scsi_buf = s->scsi_dev->info->get_buf(s->scsi_dev, tag);
     if (p) {
         usb_msd_copy_data(s);
-        if (s->usb_len == 0) {
+        if (s->packet && s->usb_len == 0) {
             /* Set s->packet to NULL before calling usb_packet_complete
                because another request may be issued before
                usb_packet_complete returns.  */
@@ -270,13 +272,13 @@ static void usb_msd_handle_reset(USBDevice *dev)
     s->mode = USB_MSDM_CBW;
 }
 
-static int usb_msd_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int usb_msd_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     MSDState *s = (MSDState *)dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
@@ -313,9 +315,9 @@ static int usb_msd_handle_control(USBDevice *dev, int request, int value,
     return ret;
 }
 
-static void usb_msd_cancel_io(USBPacket *p, void *opaque)
+static void usb_msd_cancel_io(USBDevice *dev, USBPacket *p)
 {
-    MSDState *s = opaque;
+    MSDState *s = DO_UPCAST(MSDState, dev, dev);
     s->scsi_dev->info->cancel_io(s->scsi_dev, s->tag);
     s->packet = NULL;
     s->scsi_len = 0;
@@ -396,7 +398,6 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             }
             if (s->usb_len) {
                 DPRINTF("Deferring packet %p\n", p);
-                usb_defer_packet(p, usb_msd_cancel_io, s);
                 s->packet = p;
                 ret = USB_RET_ASYNC;
             } else {
@@ -419,7 +420,6 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             if (s->data_len != 0 || len < 13)
                 goto fail;
             /* Waiting for SCSI write to complete.  */
-            usb_defer_packet(p, usb_msd_cancel_io, s);
             s->packet = p;
             ret = USB_RET_ASYNC;
             break;
@@ -453,7 +453,6 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             }
             if (s->usb_len) {
                 DPRINTF("Deferring packet %p\n", p);
-                usb_defer_packet(p, usb_msd_cancel_io, s);
                 s->packet = p;
                 ret = USB_RET_ASYNC;
             } else {
@@ -602,6 +601,7 @@ static struct USBDeviceInfo msd_info = {
     .usb_desc       = &desc,
     .init           = usb_msd_initfn,
     .handle_packet  = usb_generic_handle_packet,
+    .cancel_packet  = usb_msd_cancel_io,
     .handle_attach  = usb_desc_attach,
     .handle_reset   = usb_msd_handle_reset,
     .handle_control = usb_msd_handle_control,
diff --git a/hw/usb-musb.c b/hw/usb-musb.c
index 38986d3..6037193 100644
--- a/hw/usb-musb.c
+++ b/hw/usb-musb.c
@@ -601,7 +601,7 @@ static void musb_packet(MUSBState *s, MUSBEndPoint *ep,
     ep->packey[dir].dir = dir;
 
     if (s->port.dev)
-        ret = s->port.dev->info->handle_packet(s->port.dev, &ep->packey[dir].p);
+        ret = usb_handle_packet(s->port.dev, &ep->packey[dir].p);
     else
         ret = USB_RET_NODEV;
 
diff --git a/hw/usb-net.c b/hw/usb-net.c
index bf51bb3..9be709f 100644
--- a/hw/usb-net.c
+++ b/hw/usb-net.c
@@ -1042,13 +1042,13 @@ static void usb_net_handle_reset(USBDevice *dev)
 {
 }
 
-static int usb_net_handle_control(USBDevice *dev, int request, int value,
-                int index, int length, uint8_t *data)
+static int usb_net_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBNetState *s = (USBNetState *) dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
diff --git a/hw/usb-ohci.c b/hw/usb-ohci.c
index 32913eb..8b966f7 100644
--- a/hw/usb-ohci.c
+++ b/hw/usb-ohci.c
@@ -748,7 +748,7 @@ static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed,
             ohci->usb_packet.devep = OHCI_BM(ed->flags, ED_EN);
             ohci->usb_packet.data = ohci->usb_buf;
             ohci->usb_packet.len = len;
-            ret = dev->info->handle_packet(dev, &ohci->usb_packet);
+            ret = usb_handle_packet(dev, &ohci->usb_packet);
             if (ret != USB_RET_NODEV)
                 break;
         }
@@ -944,7 +944,7 @@ static int ohci_service_td(OHCIState *ohci, struct ohci_ed *ed)
             ohci->usb_packet.devep = OHCI_BM(ed->flags, ED_EN);
             ohci->usb_packet.data = ohci->usb_buf;
             ohci->usb_packet.len = len;
-            ret = dev->info->handle_packet(dev, &ohci->usb_packet);
+            ret = usb_handle_packet(dev, &ohci->usb_packet);
             if (ret != USB_RET_NODEV)
                 break;
         }
diff --git a/hw/usb-serial.c b/hw/usb-serial.c
index 6763d52..59cb0fb 100644
--- a/hw/usb-serial.c
+++ b/hw/usb-serial.c
@@ -146,6 +146,7 @@ static const USBDescDevice desc_device = {
             .bConfigurationValue   = 1,
             .bmAttributes          = 0x80,
             .bMaxPower             = 50,
+            .nif = 1,
             .ifs = &desc_iface0,
         },
     },
@@ -218,14 +219,14 @@ static uint8_t usb_get_modem_lines(USBSerialState *s)
     return ret;
 }
 
-static int usb_serial_handle_control(USBDevice *dev, int request, int value,
-                                  int index, int length, uint8_t *data)
+static int usb_serial_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBSerialState *s = (USBSerialState *)dev;
     int ret;
 
     DPRINTF("got control %x, value %x\n",request, value);
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
diff --git a/hw/usb-uhci.c b/hw/usb-uhci.c
index a65e0b3..c0de05b 100644
--- a/hw/usb-uhci.c
+++ b/hw/usb-uhci.c
@@ -632,7 +632,7 @@ static int uhci_broadcast_packet(UHCIState *s, USBPacket *p)
         USBDevice *dev = port->port.dev;
 
         if (dev && (port->ctrl & UHCI_PORT_EN))
-            ret = dev->info->handle_packet(dev, p);
+            ret = usb_handle_packet(dev, p);
     }
 
     DPRINTF("uhci: packet exit. ret %d len %d\n", ret, p->len);
@@ -702,11 +702,15 @@ out:
     case USB_RET_STALL:
         td->ctrl |= TD_CTRL_STALL;
         td->ctrl &= ~TD_CTRL_ACTIVE;
+        s->status |= UHCI_STS_USBERR;
+        uhci_update_irq(s);
         return 1;
 
     case USB_RET_BABBLE:
         td->ctrl |= TD_CTRL_BABBLE | TD_CTRL_STALL;
         td->ctrl &= ~TD_CTRL_ACTIVE;
+        s->status |= UHCI_STS_USBERR;
+        uhci_update_irq(s);
         /* frame interrupted */
         return -1;
 
diff --git a/hw/usb-wacom.c b/hw/usb-wacom.c
index 16be7a2..9d348e1 100644
--- a/hw/usb-wacom.c
+++ b/hw/usb-wacom.c
@@ -108,6 +108,7 @@ static const USBDescDevice desc_device_wacom = {
             .bConfigurationValue   = 1,
             .bmAttributes          = 0x80,
             .bMaxPower             = 40,
+            .nif = 1,
             .ifs = &desc_iface_wacom,
         },
     },
@@ -249,13 +250,13 @@ static void usb_wacom_handle_reset(USBDevice *dev)
     s->mode = WACOM_MODE_HID;
 }
 
-static int usb_wacom_handle_control(USBDevice *dev, int request, int value,
-                                    int index, int length, uint8_t *data)
+static int usb_wacom_handle_control(USBDevice *dev, USBPacket *p,
+               int request, int value, int index, int length, uint8_t *data)
 {
     USBWacomState *s = (USBWacomState *) dev;
     int ret;
 
-    ret = usb_desc_handle_control(dev, request, value, index, length, data);
+    ret = usb_desc_handle_control(dev, p, request, value, index, length, data);
     if (ret >= 0) {
         return ret;
     }
diff --git a/hw/usb.c b/hw/usb.c
index d8c0a75..4a39cbc 100644
--- a/hw/usb.c
+++ b/hw/usb.c
@@ -63,9 +63,10 @@ void usb_wakeup(USBDevice *dev)
    protocol)
 */
 
-#define SETUP_STATE_IDLE 0
-#define SETUP_STATE_DATA 1
-#define SETUP_STATE_ACK  2
+#define SETUP_STATE_IDLE  0
+#define SETUP_STATE_SETUP 1
+#define SETUP_STATE_DATA  2
+#define SETUP_STATE_ACK   3
 
 static int do_token_setup(USBDevice *s, USBPacket *p)
 {
@@ -82,10 +83,14 @@ static int do_token_setup(USBDevice *s, USBPacket *p)
     request = (s->setup_buf[0] << 8) | s->setup_buf[1];
     value   = (s->setup_buf[3] << 8) | s->setup_buf[2];
     index   = (s->setup_buf[5] << 8) | s->setup_buf[4];
- 
+
     if (s->setup_buf[0] & USB_DIR_IN) {
-        ret = s->info->handle_control(s, request, value, index, 
+        ret = s->info->handle_control(s, p, request, value, index,
                                       s->setup_len, s->data_buf);
+        if (ret == USB_RET_ASYNC) {
+             s->setup_state = SETUP_STATE_SETUP;
+             return USB_RET_ASYNC;
+        }
         if (ret < 0)
             return ret;
 
@@ -123,9 +128,12 @@ static int do_token_in(USBDevice *s, USBPacket *p)
     switch(s->setup_state) {
     case SETUP_STATE_ACK:
         if (!(s->setup_buf[0] & USB_DIR_IN)) {
-            s->setup_state = SETUP_STATE_IDLE;
-            ret = s->info->handle_control(s, request, value, index,
+            ret = s->info->handle_control(s, p, request, value, index,
                                           s->setup_len, s->data_buf);
+            if (ret == USB_RET_ASYNC) {
+                return USB_RET_ASYNC;
+            }
+            s->setup_state = SETUP_STATE_IDLE;
             if (ret > 0)
                 return 0;
             return ret;
@@ -238,6 +246,36 @@ int usb_generic_handle_packet(USBDevice *s, USBPacket *p)
     }
 }
 
+/* ctrl complete function for devices which use usb_generic_handle_packet and
+   may return USB_RET_ASYNC from their handle_control callback. Device code
+   which does this *must* call this function instead of the normal
+   usb_packet_complete to complete their async control packets. */
+void usb_generic_async_ctrl_complete(USBDevice *s, USBPacket *p)
+{
+    if (p->len < 0) {
+        s->setup_state = SETUP_STATE_IDLE;
+    }
+
+    switch (s->setup_state) {
+    case SETUP_STATE_SETUP:
+        if (p->len < s->setup_len) {
+            s->setup_len = p->len;
+        }
+        s->setup_state = SETUP_STATE_DATA;
+        p->len = 8;
+        break;
+
+    case SETUP_STATE_ACK:
+        s->setup_state = SETUP_STATE_IDLE;
+        p->len = 0;
+        break;
+
+    default:
+        break;
+    }
+    usb_packet_complete(s, p);
+}
+
 /* XXX: fix overflow */
 int set_usb_string(uint8_t *buf, const char *str)
 {
@@ -259,9 +297,54 @@ int set_usb_string(uint8_t *buf, const char *str)
 void usb_send_msg(USBDevice *dev, int msg)
 {
     USBPacket p;
+    int ret;
+
     memset(&p, 0, sizeof(p));
     p.pid = msg;
-    dev->info->handle_packet(dev, &p);
-
+    ret = usb_handle_packet(dev, &p);
     /* This _must_ be synchronous */
+    assert(ret != USB_RET_ASYNC);
+}
+
+/* Hand over a packet to a device for processing.  Return value
+   USB_RET_ASYNC indicates the processing isn't finished yet, the
+   driver will call usb_packet_complete() when done processing it. */
+int usb_handle_packet(USBDevice *dev, USBPacket *p)
+{
+    int ret;
+
+    assert(p->owner == NULL);
+    ret = dev->info->handle_packet(dev, p);
+    if (ret == USB_RET_ASYNC) {
+        if (p->owner == NULL) {
+            p->owner = dev;
+        } else {
+            /* We'll end up here when usb_handle_packet is called
+             * recursively due to a hub being in the chain.  Nothing
+             * to do.  Leave p->owner pointing to the device, not the
+             * hub. */;
+        }
+    }
+    return ret;
+}
+
+/* Notify the controller that an async packet is complete.  This should only
+   be called for packets previously deferred by returning USB_RET_ASYNC from
+   handle_packet. */
+void usb_packet_complete(USBDevice *dev, USBPacket *p)
+{
+    /* Note: p->owner != dev is possible in case dev is a hub */
+    assert(p->owner != NULL);
+    dev->port->ops->complete(dev, p);
+    p->owner = NULL;
+}
+
+/* Cancel an active packet.  The packed must have been deferred by
+   returning USB_RET_ASYNC from handle_packet, and not yet
+   completed.  */
+void usb_cancel_packet(USBPacket * p)
+{
+    assert(p->owner != NULL);
+    p->owner->info->cancel_packet(p->owner, p);
+    p->owner = NULL;
 }
diff --git a/hw/usb.h b/hw/usb.h
index 7e46141..9882400 100644
--- a/hw/usb.h
+++ b/hw/usb.h
@@ -124,6 +124,7 @@
 #define USB_DT_ENDPOINT			0x05
 #define USB_DT_DEVICE_QUALIFIER         0x06
 #define USB_DT_OTHER_SPEED_CONFIG       0x07
+#define USB_DT_INTERFACE_ASSOC          0x0B
 
 #define USB_ENDPOINT_XFER_CONTROL	0
 #define USB_ENDPOINT_XFER_ISOC		1
@@ -140,6 +141,7 @@ typedef struct USBDesc USBDesc;
 typedef struct USBDescID USBDescID;
 typedef struct USBDescDevice USBDescDevice;
 typedef struct USBDescConfig USBDescConfig;
+typedef struct USBDescIfaceAssoc USBDescIfaceAssoc;
 typedef struct USBDescIface USBDescIface;
 typedef struct USBDescEndpoint USBDescEndpoint;
 typedef struct USBDescOther USBDescOther;
@@ -192,6 +194,11 @@ struct USBDeviceInfo {
     int (*handle_packet)(USBDevice *dev, USBPacket *p);
 
     /*
+     * Called when a packet is canceled.
+     */
+    void (*cancel_packet)(USBDevice *dev, USBPacket *p);
+
+    /*
      * Called when device is destroyed.
      */
     void (*handle_destroy)(USBDevice *dev);
@@ -212,7 +219,7 @@ struct USBDeviceInfo {
      *
      * Returns length or one of the USB_RET_ codes.
      */
-    int (*handle_control)(USBDevice *dev, int request, int value,
+    int (*handle_control)(USBDevice *dev, USBPacket *p, int request, int value,
                           int index, int length, uint8_t *data);
 
     /*
@@ -260,38 +267,17 @@ struct USBPacket {
     uint8_t *data;
     int len;
     /* Internal use by the USB layer.  */
-    USBCallback *cancel_cb;
-    void *cancel_opaque;
+    USBDevice *owner;
 };
 
-/* Defer completion of a USB packet.  The hadle_packet routine should then
-   return USB_RET_ASYNC.  Packets that complete immediately (before
-   handle_packet returns) should not call this method.  */
-static inline void usb_defer_packet(USBPacket *p, USBCallback *cancel,
-                                    void * opaque)
-{
-    p->cancel_cb = cancel;
-    p->cancel_opaque = opaque;
-}
-
-/* Notify the controller that an async packet is complete.  This should only
-   be called for packets previously deferred with usb_defer_packet, and
-   should never be called from within handle_packet.  */
-static inline void usb_packet_complete(USBDevice *dev, USBPacket *p)
-{
-    dev->port->ops->complete(dev, p);
-}
-
-/* Cancel an active packet.  The packed must have been deferred with
-   usb_defer_packet,  and not yet completed.  */
-static inline void usb_cancel_packet(USBPacket * p)
-{
-    p->cancel_cb(p, p->cancel_opaque);
-}
+int usb_handle_packet(USBDevice *dev, USBPacket *p);
+void usb_packet_complete(USBDevice *dev, USBPacket *p);
+void usb_cancel_packet(USBPacket * p);
 
 void usb_attach(USBPort *port, USBDevice *dev);
 void usb_wakeup(USBDevice *dev);
 int usb_generic_handle_packet(USBDevice *s, USBPacket *p);
+void usb_generic_async_ctrl_complete(USBDevice *s, USBPacket *p);
 int set_usb_string(uint8_t *buf, const char *str);
 void usb_send_msg(USBDevice *dev, int msg);