qemu/hw/usb/hcd-ohci.c

/*
 * QEMU USB OHCI Emulation
 * Copyright (c) 2004 Gianni Tedesco
 * Copyright (c) 2006 CodeSourcery
 * Copyright (c) 2006 Openedhand Ltd.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 *
 * TODO:
 *  o Isochronous transfers
 *  o Allocate bandwidth in frames properly
 *  o Disable timers when nothing needs to be done, or remove timer usage
 *    all together.
 *  o Handle unrecoverable errors properly
 *  o BIOS work to boot from USB storage
*/

#include "hw/hw.h"
#include "qemu/timer.h"
#include "hw/usb.h"
#include "hw/pci/pci.h"
#include "hw/sysbus.h"
#include "hw/qdev-dma.h"

//#define DEBUG_OHCI
/* Dump packet contents.  */
//#define DEBUG_PACKET
//#define DEBUG_ISOCH
/* This causes frames to occur 1000x slower */
//#define OHCI_TIME_WARP 1

#ifdef DEBUG_OHCI
#define DPRINTF printf
#else
#define DPRINTF(...)
#endif

/* Number of Downstream Ports on the root hub.  */

#define OHCI_MAX_PORTS 15

static int64_t usb_frame_time;
static int64_t usb_bit_time;

typedef struct OHCIPort {
    USBPort port;
    uint32_t ctrl;
} OHCIPort;

typedef struct {
    USBBus bus;
    qemu_irq irq;
    MemoryRegion mem;
    DMAContext *dma;
    int num_ports;
    const char *name;

    QEMUTimer *eof_timer;
    int64_t sof_time;

    /* OHCI state */
    /* Control partition */
    uint32_t ctl, status;
    uint32_t intr_status;
    uint32_t intr;

    /* memory pointer partition */
    uint32_t hcca;
    uint32_t ctrl_head, ctrl_cur;
    uint32_t bulk_head, bulk_cur;
    uint32_t per_cur;
    uint32_t done;
    int done_count;

    /* Frame counter partition */
    uint32_t fsmps:15;
    uint32_t fit:1;
    uint32_t fi:14;
    uint32_t frt:1;
    uint16_t frame_number;
    uint16_t padding;
    uint32_t pstart;
    uint32_t lst;

    /* Root Hub partition */
    uint32_t rhdesc_a, rhdesc_b;
    uint32_t rhstatus;
    OHCIPort rhport[OHCI_MAX_PORTS];

    /* PXA27x Non-OHCI events */
    uint32_t hstatus;
    uint32_t hmask;
    uint32_t hreset;
    uint32_t htest;

    /* SM501 local memory offset */
    dma_addr_t localmem_base;

    /* Active packets.  */
    uint32_t old_ctl;
    USBPacket usb_packet;
    uint8_t usb_buf[8192];
    uint32_t async_td;
    int async_complete;

} OHCIState;

/* Host Controller Communications Area */
struct ohci_hcca {
    uint32_t intr[32];
    uint16_t frame, pad;
    uint32_t done;
};
#define HCCA_WRITEBACK_OFFSET   offsetof(struct ohci_hcca, frame)
#define HCCA_WRITEBACK_SIZE     8 /* frame, pad, done */

#define ED_WBACK_OFFSET offsetof(struct ohci_ed, head)
#define ED_WBACK_SIZE   4

static void ohci_bus_stop(OHCIState *ohci);
static void ohci_async_cancel_device(OHCIState *ohci, USBDevice *dev);

/* Bitfields for the first word of an Endpoint Desciptor.  */
#define OHCI_ED_FA_SHIFT  0
#define OHCI_ED_FA_MASK   (0x7f<<OHCI_ED_FA_SHIFT)
#define OHCI_ED_EN_SHIFT  7
#define OHCI_ED_EN_MASK   (0xf<<OHCI_ED_EN_SHIFT)
#define OHCI_ED_D_SHIFT   11
#define OHCI_ED_D_MASK    (3<<OHCI_ED_D_SHIFT)
#define OHCI_ED_S         (1<<13)
#define OHCI_ED_K         (1<<14)
#define OHCI_ED_F         (1<<15)
#define OHCI_ED_MPS_SHIFT 16
#define OHCI_ED_MPS_MASK  (0x7ff<<OHCI_ED_MPS_SHIFT)

/* Flags in the head field of an Endpoint Desciptor.  */
#define OHCI_ED_H         1
#define OHCI_ED_C         2

/* Bitfields for the first word of a Transfer Desciptor.  */
#define OHCI_TD_R         (1<<18)
#define OHCI_TD_DP_SHIFT  19
#define OHCI_TD_DP_MASK   (3<<OHCI_TD_DP_SHIFT)
#define OHCI_TD_DI_SHIFT  21
#define OHCI_TD_DI_MASK   (7<<OHCI_TD_DI_SHIFT)
#define OHCI_TD_T0        (1<<24)
#define OHCI_TD_T1        (1<<25)
#define OHCI_TD_EC_SHIFT  26
#define OHCI_TD_EC_MASK   (3<<OHCI_TD_EC_SHIFT)
#define OHCI_TD_CC_SHIFT  28
#define OHCI_TD_CC_MASK   (0xf<<OHCI_TD_CC_SHIFT)

/* Bitfields for the first word of an Isochronous Transfer Desciptor.  */
/* CC & DI - same as in the General Transfer Desciptor */
#define OHCI_TD_SF_SHIFT  0
#define OHCI_TD_SF_MASK   (0xffff<<OHCI_TD_SF_SHIFT)
#define OHCI_TD_FC_SHIFT  24
#define OHCI_TD_FC_MASK   (7<<OHCI_TD_FC_SHIFT)

/* Isochronous Transfer Desciptor - Offset / PacketStatusWord */
#define OHCI_TD_PSW_CC_SHIFT 12
#define OHCI_TD_PSW_CC_MASK  (0xf<<OHCI_TD_PSW_CC_SHIFT)
#define OHCI_TD_PSW_SIZE_SHIFT 0
#define OHCI_TD_PSW_SIZE_MASK  (0xfff<<OHCI_TD_PSW_SIZE_SHIFT)

#define OHCI_PAGE_MASK    0xfffff000
#define OHCI_OFFSET_MASK  0xfff

#define OHCI_DPTR_MASK    0xfffffff0

#define OHCI_BM(val, field) \
  (((val) & OHCI_##field##_MASK) >> OHCI_##field##_SHIFT)

#define OHCI_SET_BM(val, field, newval) do { \
    val &= ~OHCI_##field##_MASK; \
    val |= ((newval) << OHCI_##field##_SHIFT) & OHCI_##field##_MASK; \
    } while(0)

/* endpoint descriptor */
struct ohci_ed {
    uint32_t flags;
    uint32_t tail;
    uint32_t head;
    uint32_t next;
};

/* General transfer descriptor */
struct ohci_td {
    uint32_t flags;
    uint32_t cbp;
    uint32_t next;
    uint32_t be;
};

/* Isochronous transfer descriptor */
struct ohci_iso_td {
    uint32_t flags;
    uint32_t bp;
    uint32_t next;
    uint32_t be;
    uint16_t offset[8];
};

#define USB_HZ                      12000000

/* OHCI Local stuff */
#define OHCI_CTL_CBSR         ((1<<0)|(1<<1))
#define OHCI_CTL_PLE          (1<<2)
#define OHCI_CTL_IE           (1<<3)
#define OHCI_CTL_CLE          (1<<4)
#define OHCI_CTL_BLE          (1<<5)
#define OHCI_CTL_HCFS         ((1<<6)|(1<<7))
#define  OHCI_USB_RESET       0x00
#define  OHCI_USB_RESUME      0x40
#define  OHCI_USB_OPERATIONAL 0x80
#define  OHCI_USB_SUSPEND     0xc0
#define OHCI_CTL_IR           (1<<8)
#define OHCI_CTL_RWC          (1<<9)
#define OHCI_CTL_RWE          (1<<10)

#define OHCI_STATUS_HCR       (1<<0)
#define OHCI_STATUS_CLF       (1<<1)
#define OHCI_STATUS_BLF       (1<<2)
#define OHCI_STATUS_OCR       (1<<3)
#define OHCI_STATUS_SOC       ((1<<6)|(1<<7))

#define OHCI_INTR_SO          (1<<0) /* Scheduling overrun */
#define OHCI_INTR_WD          (1<<1) /* HcDoneHead writeback */
#define OHCI_INTR_SF          (1<<2) /* Start of frame */
#define OHCI_INTR_RD          (1<<3) /* Resume detect */
#define OHCI_INTR_UE          (1<<4) /* Unrecoverable error */
#define OHCI_INTR_FNO         (1<<5) /* Frame number overflow */
#define OHCI_INTR_RHSC        (1<<6) /* Root hub status change */
#define OHCI_INTR_OC          (1<<30) /* Ownership change */
#define OHCI_INTR_MIE         (1<<31) /* Master Interrupt Enable */

#define OHCI_HCCA_SIZE        0x100
#define OHCI_HCCA_MASK        0xffffff00

#define OHCI_EDPTR_MASK       0xfffffff0

#define OHCI_FMI_FI           0x00003fff
#define OHCI_FMI_FSMPS        0xffff0000
#define OHCI_FMI_FIT          0x80000000

#define OHCI_FR_RT            (1<<31)

#define OHCI_LS_THRESH        0x628

#define OHCI_RHA_RW_MASK      0x00000000 /* Mask of supported features.  */
#define OHCI_RHA_PSM          (1<<8)
#define OHCI_RHA_NPS          (1<<9)
#define OHCI_RHA_DT           (1<<10)
#define OHCI_RHA_OCPM         (1<<11)
#define OHCI_RHA_NOCP         (1<<12)
#define OHCI_RHA_POTPGT_MASK  0xff000000

#define OHCI_RHS_LPS          (1<<0)
#define OHCI_RHS_OCI          (1<<1)
#define OHCI_RHS_DRWE         (1<<15)
#define OHCI_RHS_LPSC         (1<<16)
#define OHCI_RHS_OCIC         (1<<17)
#define OHCI_RHS_CRWE         (1<<31)

#define OHCI_PORT_CCS         (1<<0)
#define OHCI_PORT_PES         (1<<1)
#define OHCI_PORT_PSS         (1<<2)
#define OHCI_PORT_POCI        (1<<3)
#define OHCI_PORT_PRS         (1<<4)
#define OHCI_PORT_PPS         (1<<8)
#define OHCI_PORT_LSDA        (1<<9)
#define OHCI_PORT_CSC         (1<<16)
#define OHCI_PORT_PESC        (1<<17)
#define OHCI_PORT_PSSC        (1<<18)
#define OHCI_PORT_OCIC        (1<<19)
#define OHCI_PORT_PRSC        (1<<20)
#define OHCI_PORT_WTC         (OHCI_PORT_CSC|OHCI_PORT_PESC|OHCI_PORT_PSSC \
                               |OHCI_PORT_OCIC|OHCI_PORT_PRSC)

#define OHCI_TD_DIR_SETUP     0x0
#define OHCI_TD_DIR_OUT       0x1
#define OHCI_TD_DIR_IN        0x2
#define OHCI_TD_DIR_RESERVED  0x3

#define OHCI_CC_NOERROR             0x0
#define OHCI_CC_CRC                 0x1
#define OHCI_CC_BITSTUFFING         0x2
#define OHCI_CC_DATATOGGLEMISMATCH  0x3
#define OHCI_CC_STALL               0x4
#define OHCI_CC_DEVICENOTRESPONDING 0x5
#define OHCI_CC_PIDCHECKFAILURE     0x6
#define OHCI_CC_UNDEXPETEDPID       0x7
#define OHCI_CC_DATAOVERRUN         0x8
#define OHCI_CC_DATAUNDERRUN        0x9
#define OHCI_CC_BUFFEROVERRUN       0xc
#define OHCI_CC_BUFFERUNDERRUN      0xd

#define OHCI_HRESET_FSBIR       (1 << 0)

/* Update IRQ levels */
static inline void ohci_intr_update(OHCIState *ohci)
{
    int level = 0;

    if ((ohci->intr & OHCI_INTR_MIE) &&
        (ohci->intr_status & ohci->intr))
        level = 1;

    qemu_set_irq(ohci->irq, level);
}

/* Set an interrupt */
static inline void ohci_set_interrupt(OHCIState *ohci, uint32_t intr)
{
    ohci->intr_status |= intr;
    ohci_intr_update(ohci);
}

/* Attach or detach a device on a root hub port.  */
static void ohci_attach(USBPort *port1)
{
    OHCIState *s = port1->opaque;
    OHCIPort *port = &s->rhport[port1->index];
    uint32_t old_state = port->ctrl;

    /* set connect status */
    port->ctrl |= OHCI_PORT_CCS | OHCI_PORT_CSC;

    /* update speed */
    if (port->port.dev->speed == USB_SPEED_LOW) {
        port->ctrl |= OHCI_PORT_LSDA;
    } else {
        port->ctrl &= ~OHCI_PORT_LSDA;
    }

    /* notify of remote-wakeup */
    if ((s->ctl & OHCI_CTL_HCFS) == OHCI_USB_SUSPEND) {
        ohci_set_interrupt(s, OHCI_INTR_RD);
    }

    DPRINTF("usb-ohci: Attached port %d\n", port1->index);

    if (old_state != port->ctrl) {
        ohci_set_interrupt(s, OHCI_INTR_RHSC);
    }
}

static void ohci_detach(USBPort *port1)
{
    OHCIState *s = port1->opaque;
    OHCIPort *port = &s->rhport[port1->index];
    uint32_t old_state = port->ctrl;

    ohci_async_cancel_device(s, port1->dev);

    /* set connect status */
    if (port->ctrl & OHCI_PORT_CCS) {
        port->ctrl &= ~OHCI_PORT_CCS;
        port->ctrl |= OHCI_PORT_CSC;
    }
    /* disable port */
    if (port->ctrl & OHCI_PORT_PES) {
        port->ctrl &= ~OHCI_PORT_PES;
        port->ctrl |= OHCI_PORT_PESC;
    }
    DPRINTF("usb-ohci: Detached port %d\n", port1->index);

    if (old_state != port->ctrl) {
        ohci_set_interrupt(s, OHCI_INTR_RHSC);
    }
}

static void ohci_wakeup(USBPort *port1)
{
    OHCIState *s = port1->opaque;
    OHCIPort *port = &s->rhport[port1->index];
    uint32_t intr = 0;
    if (port->ctrl & OHCI_PORT_PSS) {
        DPRINTF("usb-ohci: port %d: wakeup\n", port1->index);
        port->ctrl |= OHCI_PORT_PSSC;
        port->ctrl &= ~OHCI_PORT_PSS;
        intr = OHCI_INTR_RHSC;
    }
    /* Note that the controller can be suspended even if this port is not */
    if ((s->ctl & OHCI_CTL_HCFS) == OHCI_USB_SUSPEND) {
        DPRINTF("usb-ohci: remote-wakeup: SUSPEND->RESUME\n");
        /* This is the one state transition the controller can do by itself */
        s->ctl &= ~OHCI_CTL_HCFS;
        s->ctl |= OHCI_USB_RESUME;
        /* In suspend mode only ResumeDetected is possible, not RHSC:
         * see the OHCI spec 5.1.2.3.
         */
        intr = OHCI_INTR_RD;
    }
    ohci_set_interrupt(s, intr);
}

static void ohci_child_detach(USBPort *port1, USBDevice *child)
{
    OHCIState *s = port1->opaque;

    ohci_async_cancel_device(s, child);
}

static USBDevice *ohci_find_device(OHCIState *ohci, uint8_t addr)
{
    USBDevice *dev;
    int i;

    for (i = 0; i < ohci->num_ports; i++) {
        if ((ohci->rhport[i].ctrl & OHCI_PORT_PES) == 0) {
            continue;
        }
        dev = usb_find_device(&ohci->rhport[i].port, addr);
        if (dev != NULL) {
            return dev;
        }
    }
    return NULL;
}

static void ohci_stop_endpoints(OHCIState *ohci)
{
    USBDevice *dev;
    int i, j;

    for (i = 0; i < ohci->num_ports; i++) {
        dev = ohci->rhport[i].port.dev;
        if (dev && dev->attached) {
            usb_device_ep_stopped(dev, &dev->ep_ctl);
            for (j = 0; j < USB_MAX_ENDPOINTS; j++) {
                usb_device_ep_stopped(dev, &dev->ep_in[j]);
                usb_device_ep_stopped(dev, &dev->ep_out[j]);
            }
        }
    }
}

/* Reset the controller */
static void ohci_reset(void *opaque)
{
    OHCIState *ohci = opaque;
    OHCIPort *port;
    int i;

    ohci_bus_stop(ohci);
    ohci->ctl = 0;
    ohci->old_ctl = 0;
    ohci->status = 0;
    ohci->intr_status = 0;
    ohci->intr = OHCI_INTR_MIE;

    ohci->hcca = 0;
    ohci->ctrl_head = ohci->ctrl_cur = 0;
    ohci->bulk_head = ohci->bulk_cur = 0;
    ohci->per_cur = 0;
    ohci->done = 0;
    ohci->done_count = 7;

    /* FSMPS is marked TBD in OCHI 1.0, what gives ffs?
     * I took the value linux sets ...
     */
    ohci->fsmps = 0x2778;
    ohci->fi = 0x2edf;
    ohci->fit = 0;
    ohci->frt = 0;
    ohci->frame_number = 0;
    ohci->pstart = 0;
    ohci->lst = OHCI_LS_THRESH;

    ohci->rhdesc_a = OHCI_RHA_NPS | ohci->num_ports;
    ohci->rhdesc_b = 0x0; /* Impl. specific */
    ohci->rhstatus = 0;

    for (i = 0; i < ohci->num_ports; i++)
      {
        port = &ohci->rhport[i];
        port->ctrl = 0;
        if (port->port.dev && port->port.dev->attached) {
            usb_port_reset(&port->port);
        }
      }
    if (ohci->async_td) {
        usb_cancel_packet(&ohci->usb_packet);
        ohci->async_td = 0;
    }
    ohci_stop_endpoints(ohci);
    DPRINTF("usb-ohci: Reset %s\n", ohci->name);
}

/* Get an array of dwords from main memory */
static inline int get_dwords(OHCIState *ohci,
                             dma_addr_t addr, uint32_t *buf, int num)
{
    int i;

    addr += ohci->localmem_base;

    for (i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
        dma_memory_read(ohci->dma, addr, buf, sizeof(*buf));
        *buf = le32_to_cpu(*buf);
    }

    return 1;
}

/* Put an array of dwords in to main memory */
static inline int put_dwords(OHCIState *ohci,
                             dma_addr_t addr, uint32_t *buf, int num)
{
    int i;

    addr += ohci->localmem_base;

    for (i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
        uint32_t tmp = cpu_to_le32(*buf);
        dma_memory_write(ohci->dma, addr, &tmp, sizeof(tmp));
    }

    return 1;
}

/* Get an array of words from main memory */
static inline int get_words(OHCIState *ohci,
                            dma_addr_t addr, uint16_t *buf, int num)
{
    int i;

    addr += ohci->localmem_base;

    for (i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
        dma_memory_read(ohci->dma, addr, buf, sizeof(*buf));
        *buf = le16_to_cpu(*buf);
    }

    return 1;
}

/* Put an array of words in to main memory */
static inline int put_words(OHCIState *ohci,
                            dma_addr_t addr, uint16_t *buf, int num)
{
    int i;

    addr += ohci->localmem_base;

    for (i = 0; i < num; i++, buf++, addr += sizeof(*buf)) {
        uint16_t tmp = cpu_to_le16(*buf);
        dma_memory_write(ohci->dma, addr, &tmp, sizeof(tmp));
    }

    return 1;
}

static inline int ohci_read_ed(OHCIState *ohci,
                               dma_addr_t addr, struct ohci_ed *ed)
{
    return get_dwords(ohci, addr, (uint32_t *)ed, sizeof(*ed) >> 2);
}

static inline int ohci_read_td(OHCIState *ohci,
                               dma_addr_t addr, struct ohci_td *td)
{
    return get_dwords(ohci, addr, (uint32_t *)td, sizeof(*td) >> 2);
}

static inline int ohci_read_iso_td(OHCIState *ohci,
                                   dma_addr_t addr, struct ohci_iso_td *td)
{
    return (get_dwords(ohci, addr, (uint32_t *)td, 4) &&
            get_words(ohci, addr + 16, td->offset, 8));
}

static inline int ohci_read_hcca(OHCIState *ohci,
                                 dma_addr_t addr, struct ohci_hcca *hcca)
{
    dma_memory_read(ohci->dma, addr + ohci->localmem_base, hcca, sizeof(*hcca));
    return 1;
}

static inline int ohci_put_ed(OHCIState *ohci,
                              dma_addr_t addr, struct ohci_ed *ed)
{
    /* ed->tail is under control of the HCD.
     * Since just ed->head is changed by HC, just write back this
     */

    return put_dwords(ohci, addr + ED_WBACK_OFFSET,
                      (uint32_t *)((char *)ed + ED_WBACK_OFFSET),
                      ED_WBACK_SIZE >> 2);
}

static inline int ohci_put_td(OHCIState *ohci,
                              dma_addr_t addr, struct ohci_td *td)
{
    return put_dwords(ohci, addr, (uint32_t *)td, sizeof(*td) >> 2);
}

static inline int ohci_put_iso_td(OHCIState *ohci,
                                  dma_addr_t addr, struct ohci_iso_td *td)
{
    return (put_dwords(ohci, addr, (uint32_t *)td, 4) &&
            put_words(ohci, addr + 16, td->offset, 8));
}

static inline int ohci_put_hcca(OHCIState *ohci,
                                dma_addr_t addr, struct ohci_hcca *hcca)
{
    dma_memory_write(ohci->dma,
                     addr + ohci->localmem_base + HCCA_WRITEBACK_OFFSET,
                     (char *)hcca + HCCA_WRITEBACK_OFFSET,
                     HCCA_WRITEBACK_SIZE);
    return 1;
}

/* Read/Write the contents of a TD from/to main memory.  */
static void ohci_copy_td(OHCIState *ohci, struct ohci_td *td,
                         uint8_t *buf, int len, DMADirection dir)
{
    dma_addr_t ptr, n;

    ptr = td->cbp;
    n = 0x1000 - (ptr & 0xfff);
    if (n > len)
        n = len;
    dma_memory_rw(ohci->dma, ptr + ohci->localmem_base, buf, n, dir);
    if (n == len)
        return;
    ptr = td->be & ~0xfffu;
    buf += n;
    dma_memory_rw(ohci->dma, ptr + ohci->localmem_base, buf, len - n, dir);
}

/* Read/Write the contents of an ISO TD from/to main memory.  */
static void ohci_copy_iso_td(OHCIState *ohci,
                             uint32_t start_addr, uint32_t end_addr,
                             uint8_t *buf, int len, DMADirection dir)
{
    dma_addr_t ptr, n;

    ptr = start_addr;
    n = 0x1000 - (ptr & 0xfff);
    if (n > len)
        n = len;
    dma_memory_rw(ohci->dma, ptr + ohci->localmem_base, buf, n, dir);
    if (n == len)
        return;
    ptr = end_addr & ~0xfffu;
    buf += n;
    dma_memory_rw(ohci->dma, ptr + ohci->localmem_base, buf, len - n, dir);
}

static void ohci_process_lists(OHCIState *ohci, int completion);

static void ohci_async_complete_packet(USBPort *port, USBPacket *packet)
{
    OHCIState *ohci = container_of(packet, OHCIState, usb_packet);
#ifdef DEBUG_PACKET
    DPRINTF("Async packet complete\n");
#endif
    ohci->async_complete = 1;
    ohci_process_lists(ohci, 1);
}

#define USUB(a, b) ((int16_t)((uint16_t)(a) - (uint16_t)(b)))

static int ohci_service_iso_td(OHCIState *ohci, struct ohci_ed *ed,
                               int completion)
{
    int dir;
    size_t len = 0;
#ifdef DEBUG_ISOCH
    const char *str = NULL;
#endif
    int pid;
    int ret;
    int i;
    USBDevice *dev;
    USBEndpoint *ep;
    struct ohci_iso_td iso_td;
    uint32_t addr;
    uint16_t starting_frame;
    int16_t relative_frame_number;
    int frame_count;
    uint32_t start_offset, next_offset, end_offset = 0;
    uint32_t start_addr, end_addr;

    addr = ed->head & OHCI_DPTR_MASK;

    if (!ohci_read_iso_td(ohci, addr, &iso_td)) {
        printf("usb-ohci: ISO_TD read error at %x\n", addr);
        return 0;
    }

    starting_frame = OHCI_BM(iso_td.flags, TD_SF);
    frame_count = OHCI_BM(iso_td.flags, TD_FC);
    relative_frame_number = USUB(ohci->frame_number, starting_frame); 

#ifdef DEBUG_ISOCH
    printf("--- ISO_TD ED head 0x%.8x tailp 0x%.8x\n"
           "0x%.8x 0x%.8x 0x%.8x 0x%.8x\n"
           "0x%.8x 0x%.8x 0x%.8x 0x%.8x\n"
           "0x%.8x 0x%.8x 0x%.8x 0x%.8x\n"
           "frame_number 0x%.8x starting_frame 0x%.8x\n"
           "frame_count  0x%.8x relative %d\n"
           "di 0x%.8x cc 0x%.8x\n",
           ed->head & OHCI_DPTR_MASK, ed->tail & OHCI_DPTR_MASK,
           iso_td.flags, iso_td.bp, iso_td.next, iso_td.be,
           iso_td.offset[0], iso_td.offset[1], iso_td.offset[2], iso_td.offset[3],
           iso_td.offset[4], iso_td.offset[5], iso_td.offset[6], iso_td.offset[7],
           ohci->frame_number, starting_frame, 
           frame_count, relative_frame_number,         
           OHCI_BM(iso_td.flags, TD_DI), OHCI_BM(iso_td.flags, TD_CC));
#endif

    if (relative_frame_number < 0) {
        DPRINTF("usb-ohci: ISO_TD R=%d < 0\n", relative_frame_number);
        return 1;
    } else if (relative_frame_number > frame_count) {
        /* ISO TD expired - retire the TD to the Done Queue and continue with
           the next ISO TD of the same ED */
        DPRINTF("usb-ohci: ISO_TD R=%d > FC=%d\n", relative_frame_number, 
               frame_count);
        OHCI_SET_BM(iso_td.flags, TD_CC, OHCI_CC_DATAOVERRUN);
        ed->head &= ~OHCI_DPTR_MASK;
        ed->head |= (iso_td.next & OHCI_DPTR_MASK);
        iso_td.next = ohci->done;
        ohci->done = addr;
        i = OHCI_BM(iso_td.flags, TD_DI);
        if (i < ohci->done_count)
            ohci->done_count = i;
        ohci_put_iso_td(ohci, addr, &iso_td);
        return 0;
    }

    dir = OHCI_BM(ed->flags, ED_D);
    switch (dir) {
    case OHCI_TD_DIR_IN:
#ifdef DEBUG_ISOCH
        str = "in";
#endif
        pid = USB_TOKEN_IN;
        break;
    case OHCI_TD_DIR_OUT:
#ifdef DEBUG_ISOCH
        str = "out";
#endif
        pid = USB_TOKEN_OUT;
        break;
    case OHCI_TD_DIR_SETUP:
#ifdef DEBUG_ISOCH
        str = "setup";
#endif
        pid = USB_TOKEN_SETUP;
        break;
    default:
        printf("usb-ohci: Bad direction %d\n", dir);
        return 1;
    }

    if (!iso_td.bp || !iso_td.be) {
        printf("usb-ohci: ISO_TD bp 0x%.8x be 0x%.8x\n", iso_td.bp, iso_td.be);
        return 1;
    }

    start_offset = iso_td.offset[relative_frame_number];
    next_offset = iso_td.offset[relative_frame_number + 1];

    if (!(OHCI_BM(start_offset, TD_PSW_CC) & 0xe) || 
        ((relative_frame_number < frame_count) && 
         !(OHCI_BM(next_offset, TD_PSW_CC) & 0xe))) {
        printf("usb-ohci: ISO_TD cc != not accessed 0x%.8x 0x%.8x\n",
               start_offset, next_offset);
        return 1;
    }

    if ((relative_frame_number < frame_count) && (start_offset > next_offset)) {
        printf("usb-ohci: ISO_TD start_offset=0x%.8x > next_offset=0x%.8x\n",
                start_offset, next_offset);
        return 1;
    }

    if ((start_offset & 0x1000) == 0) {
        start_addr = (iso_td.bp & OHCI_PAGE_MASK) |
            (start_offset & OHCI_OFFSET_MASK);
    } else {
        start_addr = (iso_td.be & OHCI_PAGE_MASK) |
            (start_offset & OHCI_OFFSET_MASK);
    }

    if (relative_frame_number < frame_count) {
        end_offset = next_offset - 1;
        if ((end_offset & 0x1000) == 0) {
            end_addr = (iso_td.bp & OHCI_PAGE_MASK) |
                (end_offset & OHCI_OFFSET_MASK);
        } else {
            end_addr = (iso_td.be & OHCI_PAGE_MASK) |
                (end_offset & OHCI_OFFSET_MASK);
        }
    } else {
        /* Last packet in the ISO TD */
        end_addr = iso_td.be;
    }

    if ((start_addr & OHCI_PAGE_MASK) != (end_addr & OHCI_PAGE_MASK)) {
        len = (end_addr & OHCI_OFFSET_MASK) + 0x1001
            - (start_addr & OHCI_OFFSET_MASK);
    } else {
        len = end_addr - start_addr + 1;
    }

    if (len && dir != OHCI_TD_DIR_IN) {
        ohci_copy_iso_td(ohci, start_addr, end_addr, ohci->usb_buf, len,
                         DMA_DIRECTION_TO_DEVICE);
    }

    if (!completion) {
        bool int_req = relative_frame_number == frame_count &&
                       OHCI_BM(iso_td.flags, TD_DI) == 0;
        dev = ohci_find_device(ohci, OHCI_BM(ed->flags, ED_FA));
        ep = usb_ep_get(dev, pid, OHCI_BM(ed->flags, ED_EN));
        usb_packet_setup(&ohci->usb_packet, pid, ep, 0, addr, false, int_req);
        usb_packet_addbuf(&ohci->usb_packet, ohci->usb_buf, len);
        usb_handle_packet(dev, &ohci->usb_packet);
        if (ohci->usb_packet.status == USB_RET_ASYNC) {
            usb_device_flush_ep_queue(dev, ep);
            return 1;
        }
    }
    if (ohci->usb_packet.status == USB_RET_SUCCESS) {
        ret = ohci->usb_packet.actual_length;
    } else {
        ret = ohci->usb_packet.status;
    }

#ifdef DEBUG_ISOCH
    printf("so 0x%.8x eo 0x%.8x\nsa 0x%.8x ea 0x%.8x\ndir %s len %zu ret %d\n",
           start_offset, end_offset, start_addr, end_addr, str, len, ret);
#endif

    /* Writeback */
    if (dir == OHCI_TD_DIR_IN && ret >= 0 && ret <= len) {
        /* IN transfer succeeded */
        ohci_copy_iso_td(ohci, start_addr, end_addr, ohci->usb_buf, ret,
                         DMA_DIRECTION_FROM_DEVICE);
        OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_CC,
                    OHCI_CC_NOERROR);
        OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_SIZE, ret);
    } else if (dir == OHCI_TD_DIR_OUT && ret == len) {
        /* OUT transfer succeeded */
        OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_CC,
                    OHCI_CC_NOERROR);
        OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_SIZE, 0);
    } else {
        if (ret > (ssize_t) len) {
            printf("usb-ohci: DataOverrun %d > %zu\n", ret, len);
            OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_CC,
                        OHCI_CC_DATAOVERRUN);
            OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_SIZE,
                        len);
        } else if (ret >= 0) {
            printf("usb-ohci: DataUnderrun %d\n", ret);
            OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_CC,
                        OHCI_CC_DATAUNDERRUN);
        } else {
            switch (ret) {
            case USB_RET_IOERROR:
            case USB_RET_NODEV:
                OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_CC,
                            OHCI_CC_DEVICENOTRESPONDING);
                OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_SIZE,
                            0);
                break;
            case USB_RET_NAK:
            case USB_RET_STALL:
                printf("usb-ohci: got NAK/STALL %d\n", ret);
                OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_CC,
                            OHCI_CC_STALL);
                OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_SIZE,
                            0);
                break;
            default:
                printf("usb-ohci: Bad device response %d\n", ret);
                OHCI_SET_BM(iso_td.offset[relative_frame_number], TD_PSW_CC,
                            OHCI_CC_UNDEXPETEDPID);
                break;
            }
        }
    }

    if (relative_frame_number == frame_count) {
        /* Last data packet of ISO TD - retire the TD to the Done Queue */
        OHCI_SET_BM(iso_td.flags, TD_CC, OHCI_CC_NOERROR);
        ed->head &= ~OHCI_DPTR_MASK;
        ed->head |= (iso_td.next & OHCI_DPTR_MASK);
        iso_td.next = ohci->done;
        ohci->done = addr;
        i = OHCI_BM(iso_td.flags, TD_DI);
        if (i < ohci->done_count)
            ohci->done_count = i;
    }
    ohci_put_iso_td(ohci, addr, &iso_td);
    return 1;
}

/* Service a transport descriptor.
   Returns nonzero to terminate processing of this endpoint.  */

static int ohci_service_td(OHCIState *ohci, struct ohci_ed *ed)
{
    int dir;
    size_t len = 0, pktlen = 0;
#ifdef DEBUG_PACKET
    const char *str = NULL;
#endif
    int pid;
    int ret;
    int i;
    USBDevice *dev;
    USBEndpoint *ep;
    struct ohci_td td;
    uint32_t addr;
    int flag_r;
    int completion;

    addr = ed->head & OHCI_DPTR_MASK;
    /* See if this TD has already been submitted to the device.  */
    completion = (addr == ohci->async_td);
    if (completion && !ohci->async_complete) {
#ifdef DEBUG_PACKET
        DPRINTF("Skipping async TD\n");
#endif
        return 1;
    }
    if (!ohci_read_td(ohci, addr, &td)) {
        fprintf(stderr, "usb-ohci: TD read error at %x\n", addr);
        return 0;
    }

    dir = OHCI_BM(ed->flags, ED_D);
    switch (dir) {
    case OHCI_TD_DIR_OUT:
    case OHCI_TD_DIR_IN:
        /* Same value.  */
        break;
    default:
        dir = OHCI_BM(td.flags, TD_DP);
        break;
    }

    switch (dir) {
    case OHCI_TD_DIR_IN:
#ifdef DEBUG_PACKET
        str = "in";
#endif
        pid = USB_TOKEN_IN;
        break;
    case OHCI_TD_DIR_OUT:
#ifdef DEBUG_PACKET
        str = "out";
#endif
        pid = USB_TOKEN_OUT;
        break;
    case OHCI_TD_DIR_SETUP:
#ifdef DEBUG_PACKET
        str = "setup";
#endif
        pid = USB_TOKEN_SETUP;
        break;
    default:
        fprintf(stderr, "usb-ohci: Bad direction\n");
        return 1;
    }
    if (td.cbp && td.be) {
        if ((td.cbp & 0xfffff000) != (td.be & 0xfffff000)) {
            len = (td.be & 0xfff) + 0x1001 - (td.cbp & 0xfff);
        } else {
            len = (td.be - td.cbp) + 1;
        }

        pktlen = len;
        if (len && dir != OHCI_TD_DIR_IN) {
            /* The endpoint may not allow us to transfer it all now */
            pktlen = (ed->flags & OHCI_ED_MPS_MASK) >> OHCI_ED_MPS_SHIFT;
            if (pktlen > len) {
                pktlen = len;
            }
            if (!completion) {
                ohci_copy_td(ohci, &td, ohci->usb_buf, pktlen,
                             DMA_DIRECTION_TO_DEVICE);
            }
        }
    }

    flag_r = (td.flags & OHCI_TD_R) != 0;
#ifdef DEBUG_PACKET
    DPRINTF(" TD @ 0x%.8x %" PRId64 " of %" PRId64
            " bytes %s r=%d cbp=0x%.8x be=0x%.8x\n",
            addr, (int64_t)pktlen, (int64_t)len, str, flag_r, td.cbp, td.be);

    if (pktlen > 0 && dir != OHCI_TD_DIR_IN) {
        DPRINTF("  data:");
        for (i = 0; i < pktlen; i++) {
            printf(" %.2x", ohci->usb_buf[i]);
        }
        DPRINTF("\n");
    }
#endif
    if (completion) {
        ohci->async_td = 0;
        ohci->async_complete = 0;
    } else {
        if (ohci->async_td) {
            /* ??? The hardware should allow one active packet per
               endpoint.  We only allow one active packet per controller.
               This should be sufficient as long as devices respond in a
               timely manner.
            */
#ifdef DEBUG_PACKET
            DPRINTF("Too many pending packets\n");
#endif
            return 1;
        }
        dev = ohci_find_device(ohci, OHCI_BM(ed->flags, ED_FA));
        ep = usb_ep_get(dev, pid, OHCI_BM(ed->flags, ED_EN));
        usb_packet_setup(&ohci->usb_packet, pid, ep, 0, addr, !flag_r,
                         OHCI_BM(td.flags, TD_DI) == 0);
        usb_packet_addbuf(&ohci->usb_packet, ohci->usb_buf, pktlen);
        usb_handle_packet(dev, &ohci->usb_packet);
#ifdef DEBUG_PACKET
        DPRINTF("status=%d\n", ohci->usb_packet.status);
#endif
        if (ohci->usb_packet.status == USB_RET_ASYNC) {
            usb_device_flush_ep_queue(dev, ep);
            ohci->async_td = addr;
            return 1;
        }
    }
    if (ohci->usb_packet.status == USB_RET_SUCCESS) {
        ret = ohci->usb_packet.actual_length;
    } else {
        ret = ohci->usb_packet.status;
    }

    if (ret >= 0) {
        if (dir == OHCI_TD_DIR_IN) {
            ohci_copy_td(ohci, &td, ohci->usb_buf, ret,
                         DMA_DIRECTION_FROM_DEVICE);
#ifdef DEBUG_PACKET
            DPRINTF("  data:");
            for (i = 0; i < ret; i++)
                printf(" %.2x", ohci->usb_buf[i]);
            DPRINTF("\n");
#endif
        } else {
            ret = pktlen;
        }
    }

    /* Writeback */
    if (ret == pktlen || (dir == OHCI_TD_DIR_IN && ret >= 0 && flag_r)) {
        /* Transmission succeeded.  */
        if (ret == len) {
            td.cbp = 0;
        } else {
            if ((td.cbp & 0xfff) + ret > 0xfff) {
                td.cbp = (td.be & ~0xfff) + ((td.cbp + ret) & 0xfff);
            } else {
                td.cbp += ret;
            }
        }
        td.flags |= OHCI_TD_T1;
        td.flags ^= OHCI_TD_T0;
        OHCI_SET_BM(td.flags, TD_CC, OHCI_CC_NOERROR);
        OHCI_SET_BM(td.flags, TD_EC, 0);

        if ((dir != OHCI_TD_DIR_IN) && (ret != len)) {
            /* Partial packet transfer: TD not ready to retire yet */
            goto exit_no_retire;
        }

        /* Setting ED_C is part of the TD retirement process */
        ed->head &= ~OHCI_ED_C;
        if (td.flags & OHCI_TD_T0)
            ed->head |= OHCI_ED_C;
    } else {
        if (ret >= 0) {
            DPRINTF("usb-ohci: Underrun\n");
            OHCI_SET_BM(td.flags, TD_CC, OHCI_CC_DATAUNDERRUN);
        } else {
            switch (ret) {
            case USB_RET_IOERROR:
            case USB_RET_NODEV:
                OHCI_SET_BM(td.flags, TD_CC, OHCI_CC_DEVICENOTRESPONDING);
            case USB_RET_NAK:
                DPRINTF("usb-ohci: got NAK\n");
                return 1;
            case USB_RET_STALL:
                DPRINTF("usb-ohci: got STALL\n");
                OHCI_SET_BM(td.flags, TD_CC, OHCI_CC_STALL);
                break;
            case USB_RET_BABBLE:
                DPRINTF("usb-ohci: got BABBLE\n");
                OHCI_SET_BM(td.flags, TD_CC, OHCI_CC_DATAOVERRUN);
                break;
            default:
                fprintf(stderr, "usb-ohci: Bad device response %d\n", ret);
                OHCI_SET_BM(td.flags, TD_CC, OHCI_CC_UNDEXPETEDPID);
                OHCI_SET_BM(td.flags, TD_EC, 3);
                break;
            }
        }
        ed->head |= OHCI_ED_H;
    }

    /* Retire this TD */
    ed->head &= ~OHCI_DPTR_MASK;
    ed->head |= td.next & OHCI_DPTR_MASK;
    td.next = ohci->done;
    ohci->done = addr;
    i = OHCI_BM(td.flags, TD_DI);
    if (i < ohci->done_count)
        ohci->done_count = i;
exit_no_retire:
    ohci_put_td(ohci, addr, &td);
    return OHCI_BM(td.flags, TD_CC) != OHCI_CC_NOERROR;
}

/* Service an endpoint list.  Returns nonzero if active TD were found.  */
static int ohci_service_ed_list(OHCIState *ohci, uint32_t head, int completion)
{
    struct ohci_ed ed;
    uint32_t next_ed;
    uint32_t cur;
    int active;

    active = 0;

    if (head == 0)
        return 0;

    for (cur = head; cur; cur = next_ed) {
        if (!ohci_read_ed(ohci, cur, &ed)) {
            fprintf(stderr, "usb-ohci: ED read error at %x\n", cur);
            return 0;
        }

        next_ed = ed.next & OHCI_DPTR_MASK;

        if ((ed.head & OHCI_ED_H) || (ed.flags & OHCI_ED_K)) {
            uint32_t addr;
            /* Cancel pending packets for ED that have been paused.  */
            addr = ed.head & OHCI_DPTR_MASK;
            if (ohci->async_td && addr == ohci->async_td) {
                usb_cancel_packet(&ohci->usb_packet);
                ohci->async_td = 0;
                usb_device_ep_stopped(ohci->usb_packet.ep->dev,
                                      ohci->usb_packet.ep);
            }
            continue;
        }

        while ((ed.head & OHCI_DPTR_MASK) != ed.tail) {
#ifdef DEBUG_PACKET
            DPRINTF("ED @ 0x%.8x fa=%u en=%u d=%u s=%u k=%u f=%u mps=%u "
                    "h=%u c=%u\n  head=0x%.8x tailp=0x%.8x next=0x%.8x\n", cur,
                    OHCI_BM(ed.flags, ED_FA), OHCI_BM(ed.flags, ED_EN),
                    OHCI_BM(ed.flags, ED_D), (ed.flags & OHCI_ED_S)!= 0,
                    (ed.flags & OHCI_ED_K) != 0, (ed.flags & OHCI_ED_F) != 0,
                    OHCI_BM(ed.flags, ED_MPS), (ed.head & OHCI_ED_H) != 0,
                    (ed.head & OHCI_ED_C) != 0, ed.head & OHCI_DPTR_MASK,
                    ed.tail & OHCI_DPTR_MASK, ed.next & OHCI_DPTR_MASK);
#endif
            active = 1;

            if ((ed.flags & OHCI_ED_F) == 0) {
                if (ohci_service_td(ohci, &ed))
                    break;
            } else {
                /* Handle isochronous endpoints */
                if (ohci_service_iso_td(ohci, &ed, completion))
                    break;
            }
        }

        ohci_put_ed(ohci, cur, &ed);
    }

    return active;
}

/* Generate a SOF event, and set a timer for EOF */
static void ohci_sof(OHCIState *ohci)
{
    ohci->sof_time = qemu_get_clock_ns(vm_clock);
    qemu_mod_timer(ohci->eof_timer, ohci->sof_time + usb_frame_time);
    ohci_set_interrupt(ohci, OHCI_INTR_SF);
}

/* Process Control and Bulk lists.  */
static void ohci_process_lists(OHCIState *ohci, int completion)
{
    if ((ohci->ctl & OHCI_CTL_CLE) && (ohci->status & OHCI_STATUS_CLF)) {
        if (ohci->ctrl_cur && ohci->ctrl_cur != ohci->ctrl_head) {
            DPRINTF("usb-ohci: head %x, cur %x\n",
                    ohci->ctrl_head, ohci->ctrl_cur);
        }
        if (!ohci_service_ed_list(ohci, ohci->ctrl_head, completion)) {
            ohci->ctrl_cur = 0;
            ohci->status &= ~OHCI_STATUS_CLF;
        }
    }

    if ((ohci->ctl & OHCI_CTL_BLE) && (ohci->status & OHCI_STATUS_BLF)) {
        if (!ohci_service_ed_list(ohci, ohci->bulk_head, completion)) {
            ohci->bulk_cur = 0;
            ohci->status &= ~OHCI_STATUS_BLF;
        }
    }
}

/* Do frame processing on frame boundary */
static void ohci_frame_boundary(void *opaque)
{
    OHCIState *ohci = opaque;
    struct ohci_hcca hcca;

    ohci_read_hcca(ohci, ohci->hcca, &hcca);

    /* Process all the lists at the end of the frame */
    if (ohci->ctl & OHCI_CTL_PLE) {
        int n;

        n = ohci->frame_number & 0x1f;
        ohci_service_ed_list(ohci, le32_to_cpu(hcca.intr[n]), 0);
    }

    /* Cancel all pending packets if either of the lists has been disabled.  */
    if (ohci->old_ctl & (~ohci->ctl) & (OHCI_CTL_BLE | OHCI_CTL_CLE)) {
        if (ohci->async_td) {
            usb_cancel_packet(&ohci->usb_packet);
            ohci->async_td = 0;
        }
        ohci_stop_endpoints(ohci);
    }
    ohci->old_ctl = ohci->ctl;
    ohci_process_lists(ohci, 0);

    /* Frame boundary, so do EOF stuf here */
    ohci->frt = ohci->fit;

    /* Increment frame number and take care of endianness. */
    ohci->frame_number = (ohci->frame_number + 1) & 0xffff;
    hcca.frame = cpu_to_le16(ohci->frame_number);

    if (ohci->done_count == 0 && !(ohci->intr_status & OHCI_INTR_WD)) {
        if (!ohci->done)
            abort();
        if (ohci->intr & ohci->intr_status)
            ohci->done |= 1;
        hcca.done = cpu_to_le32(ohci->done);
        ohci->done = 0;
        ohci->done_count = 7;
        ohci_set_interrupt(ohci, OHCI_INTR_WD);
    }

    if (ohci->done_count != 7 && ohci->done_count != 0)
        ohci->done_count--;

    /* Do SOF stuff here */
    ohci_sof(ohci);

    /* Writeback HCCA */
    ohci_put_hcca(ohci, ohci->hcca, &hcca);
}

/* Start sending SOF tokens across the USB bus, lists are processed in
 * next frame
 */
static int ohci_bus_start(OHCIState *ohci)
{
    ohci->eof_timer = qemu_new_timer_ns(vm_clock,
                    ohci_frame_boundary,
                    ohci);

    if (ohci->eof_timer == NULL) {
        fprintf(stderr, "usb-ohci: %s: qemu_new_timer_ns failed\n", ohci->name);
        /* TODO: Signal unrecoverable error */
        return 0;
    }

    DPRINTF("usb-ohci: %s: USB Operational\n", ohci->name);

    ohci_sof(ohci);

    return 1;
}

/* Stop sending SOF tokens on the bus */
static void ohci_bus_stop(OHCIState *ohci)
{
    if (ohci->eof_timer)
        qemu_del_timer(ohci->eof_timer);
    ohci->eof_timer = NULL;
}

/* Sets a flag in a port status register but only set it if the port is
 * connected, if not set ConnectStatusChange flag. If flag is enabled
 * return 1.
 */
static int ohci_port_set_if_connected(OHCIState *ohci, int i, uint32_t val)
{
    int ret = 1;

    /* writing a 0 has no effect */
    if (val == 0)
        return 0;

    /* If CurrentConnectStatus is cleared we set
     * ConnectStatusChange
     */
    if (!(ohci->rhport[i].ctrl & OHCI_PORT_CCS)) {
        ohci->rhport[i].ctrl |= OHCI_PORT_CSC;
        if (ohci->rhstatus & OHCI_RHS_DRWE) {
            /* TODO: CSC is a wakeup event */
        }
        return 0;
    }

    if (ohci->rhport[i].ctrl & val)
        ret = 0;

    /* set the bit */
    ohci->rhport[i].ctrl |= val;

    return ret;
}

/* Set the frame interval - frame interval toggle is manipulated by the hcd only */
static void ohci_set_frame_interval(OHCIState *ohci, uint16_t val)
{
    val &= OHCI_FMI_FI;

    if (val != ohci->fi) {
        DPRINTF("usb-ohci: %s: FrameInterval = 0x%x (%u)\n",
            ohci->name, ohci->fi, ohci->fi);
    }

    ohci->fi = val;
}

static void ohci_port_power(OHCIState *ohci, int i, int p)
{
    if (p) {
        ohci->rhport[i].ctrl |= OHCI_PORT_PPS;
    } else {
        ohci->rhport[i].ctrl &= ~(OHCI_PORT_PPS|
                    OHCI_PORT_CCS|
                    OHCI_PORT_PSS|
                    OHCI_PORT_PRS);
    }
}

/* Set HcControlRegister */
static void ohci_set_ctl(OHCIState *ohci, uint32_t val)
{
    uint32_t old_state;
    uint32_t new_state;

    old_state = ohci->ctl & OHCI_CTL_HCFS;
    ohci->ctl = val;
    new_state = ohci->ctl & OHCI_CTL_HCFS;

    /* no state change */
    if (old_state == new_state)
        return;

    switch (new_state) {
    case OHCI_USB_OPERATIONAL:
        ohci_bus_start(ohci);
        break;
    case OHCI_USB_SUSPEND:
        ohci_bus_stop(ohci);
        DPRINTF("usb-ohci: %s: USB Suspended\n", ohci->name);
        break;
    case OHCI_USB_RESUME:
        DPRINTF("usb-ohci: %s: USB Resume\n", ohci->name);
        break;
    case OHCI_USB_RESET:
        ohci_reset(ohci);
        DPRINTF("usb-ohci: %s: USB Reset\n", ohci->name);
        break;
    }
}

static uint32_t ohci_get_frame_remaining(OHCIState *ohci)
{
    uint16_t fr;
    int64_t tks;

    if ((ohci->ctl & OHCI_CTL_HCFS) != OHCI_USB_OPERATIONAL)
        return (ohci->frt << 31);

    /* Being in USB operational state guarnatees sof_time was
     * set already.
     */
    tks = qemu_get_clock_ns(vm_clock) - ohci->sof_time;

    /* avoid muldiv if possible */
    if (tks >= usb_frame_time)
        return (ohci->frt << 31);

    tks = muldiv64(1, tks, usb_bit_time);
    fr = (uint16_t)(ohci->fi - tks);

    return (ohci->frt << 31) | fr;
}


/* Set root hub status */
static void ohci_set_hub_status(OHCIState *ohci, uint32_t val)
{
    uint32_t old_state;

    old_state = ohci->rhstatus;

    /* write 1 to clear OCIC */
    if (val & OHCI_RHS_OCIC)
        ohci->rhstatus &= ~OHCI_RHS_OCIC;

    if (val & OHCI_RHS_LPS) {
        int i;

        for (i = 0; i < ohci->num_ports; i++)
            ohci_port_power(ohci, i, 0);
        DPRINTF("usb-ohci: powered down all ports\n");
    }

    if (val & OHCI_RHS_LPSC) {
        int i;

        for (i = 0; i < ohci->num_ports; i++)
            ohci_port_power(ohci, i, 1);
        DPRINTF("usb-ohci: powered up all ports\n");
    }

    if (val & OHCI_RHS_DRWE)
        ohci->rhstatus |= OHCI_RHS_DRWE;

    if (val & OHCI_RHS_CRWE)
        ohci->rhstatus &= ~OHCI_RHS_DRWE;

    if (old_state != ohci->rhstatus)
        ohci_set_interrupt(ohci, OHCI_INTR_RHSC);
}

/* Set root hub port status */
static void ohci_port_set_status(OHCIState *ohci, int portnum, uint32_t val)
{
    uint32_t old_state;
    OHCIPort *port;

    port = &ohci->rhport[portnum];
    old_state = port->ctrl;

    /* Write to clear CSC, PESC, PSSC, OCIC, PRSC */
    if (val & OHCI_PORT_WTC)
        port->ctrl &= ~(val & OHCI_PORT_WTC);

    if (val & OHCI_PORT_CCS)
        port->ctrl &= ~OHCI_PORT_PES;

    ohci_port_set_if_connected(ohci, portnum, val & OHCI_PORT_PES);

    if (ohci_port_set_if_connected(ohci, portnum, val & OHCI_PORT_PSS)) {
        DPRINTF("usb-ohci: port %d: SUSPEND\n", portnum);
    }

    if (ohci_port_set_if_connected(ohci, portnum, val & OHCI_PORT_PRS)) {
        DPRINTF("usb-ohci: port %d: RESET\n", portnum);
        usb_device_reset(port->port.dev);
        port->ctrl &= ~OHCI_PORT_PRS;
        /* ??? Should this also set OHCI_PORT_PESC.  */
        port->ctrl |= OHCI_PORT_PES | OHCI_PORT_PRSC;
    }

    /* Invert order here to ensure in ambiguous case, device is
     * powered up...
     */
    if (val & OHCI_PORT_LSDA)
        ohci_port_power(ohci, portnum, 0);
    if (val & OHCI_PORT_PPS)
        ohci_port_power(ohci, portnum, 1);

    if (old_state != port->ctrl)
        ohci_set_interrupt(ohci, OHCI_INTR_RHSC);
}

static uint64_t ohci_mem_read(void *opaque,
                              hwaddr addr,
                              unsigned size)
{
    OHCIState *ohci = opaque;
    uint32_t retval;

    /* Only aligned reads are allowed on OHCI */
    if (addr & 3) {
        fprintf(stderr, "usb-ohci: Mis-aligned read\n");
        return 0xffffffff;
    } else if (addr >= 0x54 && addr < 0x54 + ohci->num_ports * 4) {
        /* HcRhPortStatus */
        retval = ohci->rhport[(addr - 0x54) >> 2].ctrl | OHCI_PORT_PPS;
    } else {
        switch (addr >> 2) {
        case 0: /* HcRevision */
            retval = 0x10;
            break;

        case 1: /* HcControl */
            retval = ohci->ctl;
            break;

        case 2: /* HcCommandStatus */
            retval = ohci->status;
            break;

        case 3: /* HcInterruptStatus */
            retval = ohci->intr_status;
            break;

        case 4: /* HcInterruptEnable */
        case 5: /* HcInterruptDisable */
            retval = ohci->intr;
            break;

        case 6: /* HcHCCA */
            retval = ohci->hcca;
            break;

        case 7: /* HcPeriodCurrentED */
            retval = ohci->per_cur;
            break;

        case 8: /* HcControlHeadED */
            retval = ohci->ctrl_head;
            break;

        case 9: /* HcControlCurrentED */
            retval = ohci->ctrl_cur;
            break;

        case 10: /* HcBulkHeadED */
            retval = ohci->bulk_head;
            break;

        case 11: /* HcBulkCurrentED */
            retval = ohci->bulk_cur;
            break;

        case 12: /* HcDoneHead */
            retval = ohci->done;
            break;

        case 13: /* HcFmInterretval */
            retval = (ohci->fit << 31) | (ohci->fsmps << 16) | (ohci->fi);
            break;

        case 14: /* HcFmRemaining */
            retval = ohci_get_frame_remaining(ohci);
            break;

        case 15: /* HcFmNumber */
            retval = ohci->frame_number;
            break;

        case 16: /* HcPeriodicStart */
            retval = ohci->pstart;
            break;

        case 17: /* HcLSThreshold */
            retval = ohci->lst;
            break;

        case 18: /* HcRhDescriptorA */
            retval = ohci->rhdesc_a;
            break;

        case 19: /* HcRhDescriptorB */
            retval = ohci->rhdesc_b;
            break;

        case 20: /* HcRhStatus */
            retval = ohci->rhstatus;
            break;

        /* PXA27x specific registers */
        case 24: /* HcStatus */
            retval = ohci->hstatus & ohci->hmask;
            break;

        case 25: /* HcHReset */
            retval = ohci->hreset;
            break;

        case 26: /* HcHInterruptEnable */
            retval = ohci->hmask;
            break;

        case 27: /* HcHInterruptTest */
            retval = ohci->htest;
            break;

        default:
            fprintf(stderr, "ohci_read: Bad offset %x\n", (int)addr);
            retval = 0xffffffff;
        }
    }

    return retval;
}

static void ohci_mem_write(void *opaque,
                           hwaddr addr,
                           uint64_t val,
                           unsigned size)
{
    OHCIState *ohci = opaque;

    /* Only aligned reads are allowed on OHCI */
    if (addr & 3) {
        fprintf(stderr, "usb-ohci: Mis-aligned write\n");
        return;
    }

    if (addr >= 0x54 && addr < 0x54 + ohci->num_ports * 4) {
        /* HcRhPortStatus */
        ohci_port_set_status(ohci, (addr - 0x54) >> 2, val);
        return;
    }

    switch (addr >> 2) {
    case 1: /* HcControl */
        ohci_set_ctl(ohci, val);
        break;

    case 2: /* HcCommandStatus */
        /* SOC is read-only */
        val = (val & ~OHCI_STATUS_SOC);

        /* Bits written as '0' remain unchanged in the register */
        ohci->status |= val;

        if (ohci->status & OHCI_STATUS_HCR)
            ohci_reset(ohci);
        break;

    case 3: /* HcInterruptStatus */
        ohci->intr_status &= ~val;
        ohci_intr_update(ohci);
        break;

    case 4: /* HcInterruptEnable */
        ohci->intr |= val;
        ohci_intr_update(ohci);
        break;

    case 5: /* HcInterruptDisable */
        ohci->intr &= ~val;
        ohci_intr_update(ohci);
        break;

    case 6: /* HcHCCA */
        ohci->hcca = val & OHCI_HCCA_MASK;
        break;

    case 7: /* HcPeriodCurrentED */
        /* Ignore writes to this read-only register, Linux does them */
        break;

    case 8: /* HcControlHeadED */
        ohci->ctrl_head = val & OHCI_EDPTR_MASK;
        break;

    case 9: /* HcControlCurrentED */
        ohci->ctrl_cur = val & OHCI_EDPTR_MASK;
        break;

    case 10: /* HcBulkHeadED */
        ohci->bulk_head = val & OHCI_EDPTR_MASK;
        break;

    case 11: /* HcBulkCurrentED */
        ohci->bulk_cur = val & OHCI_EDPTR_MASK;
        break;

    case 13: /* HcFmInterval */
        ohci->fsmps = (val & OHCI_FMI_FSMPS) >> 16;
        ohci->fit = (val & OHCI_FMI_FIT) >> 31;
        ohci_set_frame_interval(ohci, val);
        break;

    case 15: /* HcFmNumber */
        break;

    case 16: /* HcPeriodicStart */
        ohci->pstart = val & 0xffff;
        break;

    case 17: /* HcLSThreshold */
        ohci->lst = val & 0xffff;
        break;

    case 18: /* HcRhDescriptorA */
        ohci->rhdesc_a &= ~OHCI_RHA_RW_MASK;
        ohci->rhdesc_a |= val & OHCI_RHA_RW_MASK;
        break;

    case 19: /* HcRhDescriptorB */
        break;

    case 20: /* HcRhStatus */
        ohci_set_hub_status(ohci, val);
        break;

    /* PXA27x specific registers */
    case 24: /* HcStatus */
        ohci->hstatus &= ~(val & ohci->hmask);
        break;

    case 25: /* HcHReset */
        ohci->hreset = val & ~OHCI_HRESET_FSBIR;
        if (val & OHCI_HRESET_FSBIR)
            ohci_reset(ohci);
        break;

    case 26: /* HcHInterruptEnable */
        ohci->hmask = val;
        break;

    case 27: /* HcHInterruptTest */
        ohci->htest = val;
        break;

    default:
        fprintf(stderr, "ohci_write: Bad offset %x\n", (int)addr);
        break;
    }
}

static void ohci_async_cancel_device(OHCIState *ohci, USBDevice *dev)
{
    if (ohci->async_td &&
        usb_packet_is_inflight(&ohci->usb_packet) &&
        ohci->usb_packet.ep->dev == dev) {
        usb_cancel_packet(&ohci->usb_packet);
        ohci->async_td = 0;
    }
}

static const MemoryRegionOps ohci_mem_ops = {
    .read = ohci_mem_read,
    .write = ohci_mem_write,
    .endianness = DEVICE_LITTLE_ENDIAN,
};

static USBPortOps ohci_port_ops = {
    .attach = ohci_attach,
    .detach = ohci_detach,
    .child_detach = ohci_child_detach,
    .wakeup = ohci_wakeup,
    .complete = ohci_async_complete_packet,
};

static USBBusOps ohci_bus_ops = {
};

static int usb_ohci_init(OHCIState *ohci, DeviceState *dev,
                         int num_ports, dma_addr_t localmem_base,
                         char *masterbus, uint32_t firstport,
                         DMAContext *dma)
{
    int i;

    ohci->dma = dma;

    if (usb_frame_time == 0) {
#ifdef OHCI_TIME_WARP
        usb_frame_time = get_ticks_per_sec();
        usb_bit_time = muldiv64(1, get_ticks_per_sec(), USB_HZ/1000);
#else
        usb_frame_time = muldiv64(1, get_ticks_per_sec(), 1000);
        if (get_ticks_per_sec() >= USB_HZ) {
            usb_bit_time = muldiv64(1, get_ticks_per_sec(), USB_HZ);
        } else {
            usb_bit_time = 1;
        }
#endif
        DPRINTF("usb-ohci: usb_bit_time=%" PRId64 " usb_frame_time=%" PRId64 "\n",
                usb_frame_time, usb_bit_time);
    }

    ohci->num_ports = num_ports;
    if (masterbus) {
        USBPort *ports[OHCI_MAX_PORTS];
        for(i = 0; i < num_ports; i++) {
            ports[i] = &ohci->rhport[i].port;
        }
        if (usb_register_companion(masterbus, ports, num_ports,
                firstport, ohci, &ohci_port_ops,
                USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL) != 0) {
            return -1;
        }
    } else {
        usb_bus_new(&ohci->bus, &ohci_bus_ops, dev);
        for (i = 0; i < num_ports; i++) {
            usb_register_port(&ohci->bus, &ohci->rhport[i].port,
                              ohci, i, &ohci_port_ops,
                              USB_SPEED_MASK_LOW | USB_SPEED_MASK_FULL);
        }
    }

    memory_region_init_io(&ohci->mem, &ohci_mem_ops, ohci, "ohci", 256);
    ohci->localmem_base = localmem_base;

    ohci->name = object_get_typename(OBJECT(dev));
    usb_packet_init(&ohci->usb_packet);

    ohci->async_td = 0;
    qemu_register_reset(ohci_reset, ohci);

    return 0;
}

typedef struct {
    PCIDevice pci_dev;
    OHCIState state;
    char *masterbus;
    uint32_t num_ports;
    uint32_t firstport;
} OHCIPCIState;

static int usb_ohci_initfn_pci(struct PCIDevice *dev)
{
    OHCIPCIState *ohci = DO_UPCAST(OHCIPCIState, pci_dev, dev);

    ohci->pci_dev.config[PCI_CLASS_PROG] = 0x10; /* OHCI */
    ohci->pci_dev.config[PCI_INTERRUPT_PIN] = 0x01; /* interrupt pin A */

    if (usb_ohci_init(&ohci->state, &dev->qdev, ohci->num_ports, 0,
                      ohci->masterbus, ohci->firstport,
                      pci_dma_context(dev)) != 0) {
        return -1;
    }
    ohci->state.irq = ohci->pci_dev.irq[0];

    /* TODO: avoid cast below by using dev */
    pci_register_bar(&ohci->pci_dev, 0, 0, &ohci->state.mem);
    return 0;
}

typedef struct {
    SysBusDevice busdev;
    OHCIState ohci;
    uint32_t num_ports;
    dma_addr_t dma_offset;
} OHCISysBusState;

static int ohci_init_pxa(SysBusDevice *dev)
{
    OHCISysBusState *s = FROM_SYSBUS(OHCISysBusState, dev);

    /* Cannot fail as we pass NULL for masterbus */
    usb_ohci_init(&s->ohci, &dev->qdev, s->num_ports, s->dma_offset, NULL, 0,
                  &dma_context_memory);
    sysbus_init_irq(dev, &s->ohci.irq);
    sysbus_init_mmio(dev, &s->ohci.mem);

    return 0;
}

static Property ohci_pci_properties[] = {
    DEFINE_PROP_STRING("masterbus", OHCIPCIState, masterbus),
    DEFINE_PROP_UINT32("num-ports", OHCIPCIState, num_ports, 3),
    DEFINE_PROP_UINT32("firstport", OHCIPCIState, firstport, 0),
    DEFINE_PROP_END_OF_LIST(),
};

static void ohci_pci_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);

    k->init = usb_ohci_initfn_pci;
    k->vendor_id = PCI_VENDOR_ID_APPLE;
    k->device_id = PCI_DEVICE_ID_APPLE_IPID_USB;
    k->class_id = PCI_CLASS_SERIAL_USB;
    k->no_hotplug = 1;
    dc->desc = "Apple USB Controller";
    dc->props = ohci_pci_properties;
}

static const TypeInfo ohci_pci_info = {
    .name          = "pci-ohci",
    .parent        = TYPE_PCI_DEVICE,
    .instance_size = sizeof(OHCIPCIState),
    .class_init    = ohci_pci_class_init,
};

static Property ohci_sysbus_properties[] = {
    DEFINE_PROP_UINT32("num-ports", OHCISysBusState, num_ports, 3),
    DEFINE_PROP_DMAADDR("dma-offset", OHCISysBusState, dma_offset, 3),
    DEFINE_PROP_END_OF_LIST(),
};

static void ohci_sysbus_class_init(ObjectClass *klass, void *data)
{
    DeviceClass *dc = DEVICE_CLASS(klass);
    SysBusDeviceClass *sbc = SYS_BUS_DEVICE_CLASS(klass);

    sbc->init = ohci_init_pxa;
    dc->desc = "OHCI USB Controller";
    dc->props = ohci_sysbus_properties;
}

static const TypeInfo ohci_sysbus_info = {
    .name          = "sysbus-ohci",
    .parent        = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(OHCISysBusState),
    .class_init    = ohci_sysbus_class_init,
};

static void ohci_register_types(void)
{
    type_register_static(&ohci_pci_info);
    type_register_static(&ohci_sysbus_info);
}

type_init(ohci_register_types)