Archipelago » qemu

/*

 * QEMU USB EHCI Emulation

 *

 * Copyright(c) 2008  Emutex Ltd. (address@hidden)

 * Copyright(c) 2011-2012 Red Hat, Inc.

 *

 * Red Hat Authors:

 * Gerd Hoffmann <kraxel@redhat.com>

 * Hans de Goede <hdegoede@redhat.com>

 *

 * 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/>.

 */

#include "hw/hw.h"

#include "qemu-timer.h"

#include "hw/usb.h"

#include "hw/pci.h"

#include "monitor.h"

#include "trace.h"

#include "dma.h"

#include "sysemu.h"

#define EHCI_DEBUG   0

#if EHCI_DEBUG

#define DPRINTF printf

#else

#define DPRINTF(...)

#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 reserved or are read-only are masked out of values

 * written to us by software

 */

#define PORTSC_RO_MASK       0x007001c0

#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_NS   (1000000000 / FRAME_TIMER_FREQ)

#define NB_MAXINTRATE    8        // Max rate at which controller issues ints

#define NB_PORTS         6        // Number of downstream ports

#define BUFF_SIZE        5*4096   // Max bytes to transfer per transaction

#define MAX_QH           100      // Max allowable queue heads in a chain

#define MIN_FR_PER_TICK  3        // Min frames to process when catching up

/*  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_FETCHSITD,

    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

#define ITD_BUFPTR_MULT_SH       0

} 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

#define QTD_BUFPTR_SH                 12

} 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 EHCIPacket EHCIPacket;

typedef struct EHCIQueue EHCIQueue;

typedef struct EHCIState EHCIState;

enum async_state {

    EHCI_ASYNC_NONE = 0,

    EHCI_ASYNC_INITIALIZED,

    EHCI_ASYNC_INFLIGHT,

    EHCI_ASYNC_FINISHED,

};

struct EHCIPacket {

    EHCIQueue *queue;

    QTAILQ_ENTRY(EHCIPacket) next;

    EHCIqtd qtd;           /* copy of current QTD (being worked on) */

    uint32_t qtdaddr;      /* address QTD read from                 */

    USBPacket packet;

    QEMUSGList sgl;

    int pid;

    enum async_state async;

    int usb_status;

};

struct EHCIQueue {

    EHCIState *ehci;

    QTAILQ_ENTRY(EHCIQueue) next;

    uint32_t seen;

    uint64_t ts;

    int async;

    int transact_ctr;

    /* 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                 */

    uint32_t qtdaddr;      /* address QTD read from                */

    USBDevice *dev;

    QTAILQ_HEAD(pkts_head, EHCIPacket) packets;

};

typedef QTAILQ_HEAD(EHCIQueueHead, EHCIQueue) EHCIQueueHead;

struct EHCIState {

    PCIDevice dev;

    USBBus bus;

    qemu_irq irq;

    MemoryRegion mem;

    MemoryRegion mem_caps;

    MemoryRegion mem_opreg;

    MemoryRegion mem_ports;

    int companion_count;

    /* properties */

    uint32_t maxframes;

    /*

     *  EHCI spec version 1.0 Section 2.3

     *  Host Controller Operational Registers

     */

    uint8_t caps[OPREGBASE];

    union {

        uint32_t opreg[(PORTSC_BEGIN-OPREGBASE)/sizeof(uint32_t)];

        struct {

            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

     */

    QEMUTimer *frame_timer;

    QEMUBH *async_bh;

    uint32_t astate;         /* Current state in asynchronous schedule */

    uint32_t pstate;         /* Current state in periodic schedule     */

    USBPort ports[NB_PORTS];

    USBPort *companion_ports[NB_PORTS];

    uint32_t usbsts_pending;

    uint32_t usbsts_frindex;

    EHCIQueueHead aqueues;

    EHCIQueueHead pqueues;

    /* which address to look at next */

    uint32_t a_fetch_addr;

    uint32_t p_fetch_addr;

    USBPacket ipacket;

    QEMUSGList isgl;

    uint64_t last_run_ns;

    uint32_t async_stepdown;

    bool int_req_by_async;

};

#define SET_LAST_RUN_CLOCK(s) \

    (s)->last_run_ns = qemu_get_clock_ns(vm_clock);

/* 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)

static const char *ehci_state_names[] = {

    [EST_INACTIVE]     = "INACTIVE",

    [EST_ACTIVE]       = "ACTIVE",

    [EST_EXECUTING]    = "EXECUTING",

    [EST_SLEEPING]     = "SLEEPING",

    [EST_WAITLISTHEAD] = "WAITLISTHEAD",

    [EST_FETCHENTRY]   = "FETCH ENTRY",

    [EST_FETCHQH]      = "FETCH QH",

    [EST_FETCHITD]     = "FETCH ITD",

    [EST_ADVANCEQUEUE] = "ADVANCEQUEUE",

    [EST_FETCHQTD]     = "FETCH QTD",

    [EST_EXECUTE]      = "EXECUTE",

    [EST_WRITEBACK]    = "WRITEBACK",

    [EST_HORIZONTALQH] = "HORIZONTALQH",

};

static const char *ehci_mmio_names[] = {

    [USBCMD]            = "USBCMD",

    [USBSTS]            = "USBSTS",

    [USBINTR]           = "USBINTR",

    [FRINDEX]           = "FRINDEX",

    [PERIODICLISTBASE]  = "P-LIST BASE",

    [ASYNCLISTADDR]     = "A-LIST ADDR",

    [CONFIGFLAG]        = "CONFIGFLAG",

};

static int ehci_state_executing(EHCIQueue *q);

static int ehci_state_writeback(EHCIQueue *q);

static int ehci_fill_queue(EHCIPacket *p);

static const char *nr2str(const char **n, size_t len, uint32_t nr)

{

    if (nr < len && n[nr] != NULL) {

        return n[nr];

    } else {

        return "unknown";

    }

}

static const char *state2str(uint32_t state)

{

    return nr2str(ehci_state_names, ARRAY_SIZE(ehci_state_names), state);

}

static const char *addr2str(hwaddr addr)

{

    return nr2str(ehci_mmio_names, ARRAY_SIZE(ehci_mmio_names),

                  addr + OPREGBASE);

}

static void ehci_trace_usbsts(uint32_t mask, int state)

{

    /* interrupts */

    if (mask & USBSTS_INT) {

        trace_usb_ehci_usbsts("INT", state);

    }

    if (mask & USBSTS_ERRINT) {

        trace_usb_ehci_usbsts("ERRINT", state);

    }

    if (mask & USBSTS_PCD) {

        trace_usb_ehci_usbsts("PCD", state);

    }

    if (mask & USBSTS_FLR) {

        trace_usb_ehci_usbsts("FLR", state);

    }

    if (mask & USBSTS_HSE) {

        trace_usb_ehci_usbsts("HSE", state);

    }

    if (mask & USBSTS_IAA) {

        trace_usb_ehci_usbsts("IAA", state);

    }

    /* status */

    if (mask & USBSTS_HALT) {

        trace_usb_ehci_usbsts("HALT", state);

    }

    if (mask & USBSTS_REC) {

        trace_usb_ehci_usbsts("REC", state);

    }

    if (mask & USBSTS_PSS) {

        trace_usb_ehci_usbsts("PSS", state);

    }

    if (mask & USBSTS_ASS) {

        trace_usb_ehci_usbsts("ASS", state);

    }

}

static inline void ehci_set_usbsts(EHCIState *s, int mask)

{

    if ((s->usbsts & mask) == mask) {

        return;

    }

    ehci_trace_usbsts(mask, 1);

    s->usbsts |= mask;

}

static inline void ehci_clear_usbsts(EHCIState *s, int mask)

{

    if ((s->usbsts & mask) == 0) {

        return;

    }

    ehci_trace_usbsts(mask, 0);

    s->usbsts &= ~mask;

}

/* update irq line */

static inline void ehci_update_irq(EHCIState *s)

{

    int level = 0;

    if ((s->usbsts & USBINTR_MASK) & s->usbintr) {

        level = 1;

    }

    trace_usb_ehci_irq(level, s->frindex, s->usbsts, s->usbintr);

    qemu_set_irq(s->irq, level);

}

/* flag interrupt condition */

static inline void ehci_raise_irq(EHCIState *s, int intr)

{

    if (intr & (USBSTS_PCD | USBSTS_FLR | USBSTS_HSE)) {

        s->usbsts |= intr;

        ehci_update_irq(s);

    } else {

        s->usbsts_pending |= intr;

    }

}

/*

 * Commit pending interrupts (added via ehci_raise_irq),

 * at the rate allowed by "Interrupt Threshold Control".

 */

static inline void ehci_commit_irq(EHCIState *s)

{

    uint32_t itc;

    if (!s->usbsts_pending) {

        return;

    }

    if (s->usbsts_frindex > s->frindex) {

        return;

    }

    itc = (s->usbcmd >> 16) & 0xff;

    s->usbsts |= s->usbsts_pending;

    s->usbsts_pending = 0;

    s->usbsts_frindex = s->frindex + itc;

    ehci_update_irq(s);

}

static void ehci_update_halt(EHCIState *s)

{

    if (s->usbcmd & USBCMD_RUNSTOP) {

        ehci_clear_usbsts(s, USBSTS_HALT);

    } else {

        if (s->astate == EST_INACTIVE && s->pstate == EST_INACTIVE) {

            ehci_set_usbsts(s, USBSTS_HALT);

        }

    }

}

static void ehci_set_state(EHCIState *s, int async, int state)

{

    if (async) {

        trace_usb_ehci_state("async", state2str(state));

        s->astate = state;

        if (s->astate == EST_INACTIVE) {

            ehci_clear_usbsts(s, USBSTS_ASS);

            ehci_update_halt(s);

        } else {

            ehci_set_usbsts(s, USBSTS_ASS);

        }

    } else {

        trace_usb_ehci_state("periodic", state2str(state));

        s->pstate = state;

        if (s->pstate == EST_INACTIVE) {

            ehci_clear_usbsts(s, USBSTS_PSS);

            ehci_update_halt(s);

        } else {

            ehci_set_usbsts(s, USBSTS_PSS);

        }

    }

}

static int ehci_get_state(EHCIState *s, int async)

{

    return async ? s->astate : s->pstate;

}

static void ehci_set_fetch_addr(EHCIState *s, int async, uint32_t addr)

{

    if (async) {

        s->a_fetch_addr = addr;

    } else {

        s->p_fetch_addr = addr;

    }

}

static int ehci_get_fetch_addr(EHCIState *s, int async)

{

    return async ? s->a_fetch_addr : s->p_fetch_addr;

}

static void ehci_trace_qh(EHCIQueue *q, hwaddr addr, EHCIqh *qh)

{

    /* need three here due to argument count limits */

    trace_usb_ehci_qh_ptrs(q, addr, qh->next,

                           qh->current_qtd, qh->next_qtd, qh->altnext_qtd);

    trace_usb_ehci_qh_fields(addr,

                             get_field(qh->epchar, QH_EPCHAR_RL),

                             get_field(qh->epchar, QH_EPCHAR_MPLEN),

                             get_field(qh->epchar, QH_EPCHAR_EPS),

                             get_field(qh->epchar, QH_EPCHAR_EP),

                             get_field(qh->epchar, QH_EPCHAR_DEVADDR));

    trace_usb_ehci_qh_bits(addr,

                           (bool)(qh->epchar & QH_EPCHAR_C),

                           (bool)(qh->epchar & QH_EPCHAR_H),

                           (bool)(qh->epchar & QH_EPCHAR_DTC),

                           (bool)(qh->epchar & QH_EPCHAR_I));

}

static void ehci_trace_qtd(EHCIQueue *q, hwaddr addr, EHCIqtd *qtd)

{

    /* need three here due to argument count limits */

    trace_usb_ehci_qtd_ptrs(q, addr, qtd->next, qtd->altnext);

    trace_usb_ehci_qtd_fields(addr,

                              get_field(qtd->token, QTD_TOKEN_TBYTES),

                              get_field(qtd->token, QTD_TOKEN_CPAGE),

                              get_field(qtd->token, QTD_TOKEN_CERR),

                              get_field(qtd->token, QTD_TOKEN_PID));

    trace_usb_ehci_qtd_bits(addr,

                            (bool)(qtd->token & QTD_TOKEN_IOC),

                            (bool)(qtd->token & QTD_TOKEN_ACTIVE),

                            (bool)(qtd->token & QTD_TOKEN_HALT),

                            (bool)(qtd->token & QTD_TOKEN_BABBLE),

                            (bool)(qtd->token & QTD_TOKEN_XACTERR));

}

static void ehci_trace_itd(EHCIState *s, hwaddr addr, EHCIitd *itd)

{

    trace_usb_ehci_itd(addr, itd->next,

                       get_field(itd->bufptr[1], ITD_BUFPTR_MAXPKT),

                       get_field(itd->bufptr[2], ITD_BUFPTR_MULT),

                       get_field(itd->bufptr[0], ITD_BUFPTR_EP),

                       get_field(itd->bufptr[0], ITD_BUFPTR_DEVADDR));

}

static void ehci_trace_sitd(EHCIState *s, hwaddr addr,

                            EHCIsitd *sitd)

{

    trace_usb_ehci_sitd(addr, sitd->next,

                        (bool)(sitd->results & SITD_RESULTS_ACTIVE));

}

static void ehci_trace_guest_bug(EHCIState *s, const char *message)

{

    trace_usb_ehci_guest_bug(message);

    fprintf(stderr, "ehci warning: %s\n", message);

}

static inline bool ehci_enabled(EHCIState *s)

{

    return s->usbcmd & USBCMD_RUNSTOP;

}

static inline bool ehci_async_enabled(EHCIState *s)

{

    return ehci_enabled(s) && (s->usbcmd & USBCMD_ASE);

}

static inline bool ehci_periodic_enabled(EHCIState *s)

{

    return ehci_enabled(s) && (s->usbcmd & USBCMD_PSE);

}

/* packet management */

static EHCIPacket *ehci_alloc_packet(EHCIQueue *q)

{

    EHCIPacket *p;

    p = g_new0(EHCIPacket, 1);

    p->queue = q;

    usb_packet_init(&p->packet);

    QTAILQ_INSERT_TAIL(&q->packets, p, next);

    trace_usb_ehci_packet_action(p->queue, p, "alloc");

    return p;

}

static void ehci_free_packet(EHCIPacket *p)

{

    if (p->async == EHCI_ASYNC_FINISHED) {

        int state = ehci_get_state(p->queue->ehci, p->queue->async);

        /* This is a normal, but rare condition (cancel racing completion) */

        fprintf(stderr, "EHCI: Warning packet completed but not processed\n");

        ehci_state_executing(p->queue);

        ehci_state_writeback(p->queue);

        ehci_set_state(p->queue->ehci, p->queue->async, state);

        /* state_writeback recurses into us with async == EHCI_ASYNC_NONE!! */

        return;

    }

    trace_usb_ehci_packet_action(p->queue, p, "free");

    if (p->async == EHCI_ASYNC_INITIALIZED) {

        usb_packet_unmap(&p->packet, &p->sgl);

        qemu_sglist_destroy(&p->sgl);

    }

    if (p->async == EHCI_ASYNC_INFLIGHT) {

        usb_cancel_packet(&p->packet);

        usb_packet_unmap(&p->packet, &p->sgl);

        qemu_sglist_destroy(&p->sgl);

    }

    QTAILQ_REMOVE(&p->queue->packets, p, next);

    usb_packet_cleanup(&p->packet);

    g_free(p);

}

/* queue management */

static EHCIQueue *ehci_alloc_queue(EHCIState *ehci, uint32_t addr, int async)

{

    EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;

    EHCIQueue *q;

    q = g_malloc0(sizeof(*q));

    q->ehci = ehci;

    q->qhaddr = addr;

    q->async = async;

    QTAILQ_INIT(&q->packets);

    QTAILQ_INSERT_HEAD(head, q, next);

    trace_usb_ehci_queue_action(q, "alloc");

    return q;

}

static int ehci_cancel_queue(EHCIQueue *q)

{

    EHCIPacket *p;

    int packets = 0;

    p = QTAILQ_FIRST(&q->packets);

    if (p == NULL) {

        return 0;

    }

    trace_usb_ehci_queue_action(q, "cancel");

    do {

        ehci_free_packet(p);

        packets++;

    } while ((p = QTAILQ_FIRST(&q->packets)) != NULL);

    return packets;

}

static int ehci_reset_queue(EHCIQueue *q)

{

    int packets;

    trace_usb_ehci_queue_action(q, "reset");

    packets = ehci_cancel_queue(q);

    q->dev = NULL;

    q->qtdaddr = 0;

    return packets;

}

static void ehci_free_queue(EHCIQueue *q, const char *warn)

{

    EHCIQueueHead *head = q->async ? &q->ehci->aqueues : &q->ehci->pqueues;

    int cancelled;

    trace_usb_ehci_queue_action(q, "free");

    cancelled = ehci_cancel_queue(q);

    if (warn && cancelled > 0) {

        ehci_trace_guest_bug(q->ehci, warn);

    }

    QTAILQ_REMOVE(head, q, next);

    g_free(q);

}

static EHCIQueue *ehci_find_queue_by_qh(EHCIState *ehci, uint32_t addr,

                                        int async)

{

    EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;

    EHCIQueue *q;

    QTAILQ_FOREACH(q, head, next) {

        if (addr == q->qhaddr) {

            return q;

        }

    }

    return NULL;

}

static void ehci_queues_rip_unused(EHCIState *ehci, int async)

{

    EHCIQueueHead *head = async ? &ehci->aqueues : &ehci->pqueues;

    const char *warn = async ? "guest unlinked busy QH" : NULL;

    uint64_t maxage = FRAME_TIMER_NS * ehci->maxframes * 4;

    EHCIQueue *q, *tmp;