tinyusb/src/host/ohci/ohci.c

/* 
 * The MIT License (MIT)
 *
 * Copyright (c) 2019 Ha Thach (tinyusb.org)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * This file is part of the TinyUSB stack.
 */

#include <common/tusb_common.h>

#if TUSB_OPT_HOST_ENABLED && (CFG_TUSB_MCU == OPT_MCU_LPC175X_6X || CFG_TUSB_MCU == OPT_MCU_LPC40XX)
//--------------------------------------------------------------------+
// INCLUDE
//--------------------------------------------------------------------+
#include "osal/osal.h"

#include "../hcd.h"
#include "../usbh_hcd.h"
#include "ohci.h"

// TODO remove
#include "chip.h"

//--------------------------------------------------------------------+
// MACRO CONSTANT TYPEDEF
//--------------------------------------------------------------------+
#define OHCI_REG               ((ohci_registers_t *) LPC_USB_BASE)

enum {
  OHCI_CONTROL_FUNCSTATE_RESET = 0,
  OHCI_CONTROL_FUNCSTATE_RESUME,
  OHCI_CONTROL_FUNCSTATE_OPERATIONAL,
  OHCI_CONTROL_FUNCSTATE_SUSPEND
};

enum {
  OHCI_CONTROL_CONTROL_BULK_RATIO           = 3, ///< This specifies the service ratio between Control and Bulk EDs. 0 = 1:1, 3 = 4:1
  OHCI_CONTROL_LIST_PERIODIC_ENABLE_MASK    = TU_BIT(2),
  OHCI_CONTROL_LIST_ISOCHRONOUS_ENABLE_MASK = TU_BIT(3),
  OHCI_CONTROL_LIST_CONTROL_ENABLE_MASK     = TU_BIT(4),
  OHCI_CONTROL_LIST_BULK_ENABLE_MASK        = TU_BIT(5),
};

enum {
  OHCI_FMINTERVAL_FI    = 0x2EDF, // 7.3.1 nominal (reset) value
  OHCI_FMINTERVAL_FSMPS = (6*(OHCI_FMINTERVAL_FI-210)) / 7, // 5.4 calculated based on maximum overhead + bit stuffing
};

enum {
  OHCI_PERIODIC_START = 0x3E67
};

enum {
  OHCI_INT_SCHEDULING_OVERUN_MASK    = TU_BIT(0),
  OHCI_INT_WRITEBACK_DONEHEAD_MASK   = TU_BIT(1),
  OHCI_INT_SOF_MASK                  = TU_BIT(2),
  OHCI_INT_RESUME_DETECTED_MASK      = TU_BIT(3),
  OHCI_INT_UNRECOVERABLE_ERROR_MASK  = TU_BIT(4),
  OHCI_INT_FRAME_OVERFLOW_MASK       = TU_BIT(5),
  OHCI_INT_RHPORT_STATUS_CHANGE_MASK = TU_BIT(6),

  OHCI_INT_OWNERSHIP_CHANGE_MASK     = TU_BIT(30),
  OHCI_INT_MASTER_ENABLE_MASK        = TU_BIT(31),
};

enum {
  OHCI_RHPORT_CURRENT_CONNECT_STATUS_MASK      = TU_BIT(0),
  OHCI_RHPORT_PORT_ENABLE_STATUS_MASK          = TU_BIT(1),
  OHCI_RHPORT_PORT_SUSPEND_STATUS_MASK         = TU_BIT(2),
  OHCI_RHPORT_PORT_OVER_CURRENT_INDICATOR_MASK = TU_BIT(3),
  OHCI_RHPORT_PORT_RESET_STATUS_MASK           = TU_BIT(4), ///< write '1' to reset port

  OHCI_RHPORT_PORT_POWER_STATUS_MASK           = TU_BIT(8),
  OHCI_RHPORT_LOW_SPEED_DEVICE_ATTACHED_MASK   = TU_BIT(9),

  OHCI_RHPORT_CONNECT_STATUS_CHANGE_MASK       = TU_BIT(16),
  OHCI_RHPORT_PORT_ENABLE_CHANGE_MASK          = TU_BIT(17),
  OHCI_RHPORT_PORT_SUSPEND_CHANGE_MASK         = TU_BIT(18),
  OHCI_RHPORT_OVER_CURRENT_CHANGE_MASK         = TU_BIT(19),
  OHCI_RHPORT_PORT_RESET_CHANGE_MASK           = TU_BIT(20),

  OHCI_RHPORT_ALL_CHANGE_MASK = OHCI_RHPORT_CONNECT_STATUS_CHANGE_MASK | OHCI_RHPORT_PORT_ENABLE_CHANGE_MASK |
    OHCI_RHPORT_PORT_SUSPEND_CHANGE_MASK | OHCI_RHPORT_OVER_CURRENT_CHANGE_MASK | OHCI_RHPORT_PORT_RESET_CHANGE_MASK
};

enum {
  OHCI_CCODE_NO_ERROR              = 0,
  OHCI_CCODE_CRC                   = 1,
	OHCI_CCODE_BIT_STUFFING          = 2,
	OHCI_CCODE_DATA_TOGGLE_MISMATCH  = 3,
	OHCI_CCODE_STALL                 = 4,
	OHCI_CCODE_DEVICE_NOT_RESPONDING = 5,
	OHCI_CCODE_PID_CHECK_FAILURE     = 6,
	OHCI_CCODE_UNEXPECTED_PID        = 7,
	OHCI_CCODE_DATA_OVERRUN          = 8,
	OHCI_CCODE_DATA_UNDERRUN         = 9,
	OHCI_CCODE_BUFFER_OVERRUN        = 12,
	OHCI_CCODE_BUFFER_UNDERRUN       = 13,
	OHCI_CCODE_NOT_ACCESSED          = 14,
};

enum {
  OHCI_INT_ON_COMPLETE_YES = 0,
  OHCI_INT_ON_COMPLETE_NO  = TU_BIN8(111)
};
//--------------------------------------------------------------------+
// INTERNAL OBJECT & FUNCTION DECLARATION
//--------------------------------------------------------------------+
CFG_TUSB_MEM_SECTION TU_ATTR_ALIGNED(256) static ohci_data_t ohci_data;

static ohci_ed_t * const p_ed_head[] =
{
    [TUSB_XFER_CONTROL]     = &ohci_data.control[0].ed,
    [TUSB_XFER_BULK   ]     = &ohci_data.bulk_head_ed,
    [TUSB_XFER_INTERRUPT]   = &ohci_data.period_head_ed,
    [TUSB_XFER_ISOCHRONOUS] = NULL // TODO Isochronous
};

static void ed_list_insert(ohci_ed_t * p_pre, ohci_ed_t * p_ed);
static void ed_list_remove_by_addr(ohci_ed_t * p_head, uint8_t dev_addr);

//--------------------------------------------------------------------+
// USBH-HCD API
//--------------------------------------------------------------------+
// Initialization according to 5.1.1.4
bool hcd_init(void)
{
  //------------- Data Structure init -------------//
  tu_memclr(&ohci_data, sizeof(ohci_data_t));
  for(uint8_t i=0; i<32; i++)
  { // assign all interrupt pointes to period head ed
    ohci_data.hcca.interrupt_table[i] = (uint32_t) &ohci_data.period_head_ed;
  }

  ohci_data.control[0].ed.skip  = 1;
  ohci_data.bulk_head_ed.skip   = 1;
  ohci_data.period_head_ed.skip = 1;

  // reset controller
  OHCI_REG->command_status_bit.controller_reset = 1;
  while( OHCI_REG->command_status_bit.controller_reset ) {} // should not take longer than 10 us

  //------------- init ohci registers -------------//
  OHCI_REG->control_head_ed = (uint32_t) &ohci_data.control[0].ed;
  OHCI_REG->bulk_head_ed    = (uint32_t) &ohci_data.bulk_head_ed;
  OHCI_REG->hcca            = (uint32_t) &ohci_data.hcca;

  OHCI_REG->interrupt_disable = OHCI_REG->interrupt_enable; // disable all interrupts
  OHCI_REG->interrupt_status  = OHCI_REG->interrupt_status; // clear current set bits
  OHCI_REG->interrupt_enable  = OHCI_INT_WRITEBACK_DONEHEAD_MASK | OHCI_INT_RESUME_DETECTED_MASK |
      OHCI_INT_UNRECOVERABLE_ERROR_MASK | OHCI_INT_FRAME_OVERFLOW_MASK | OHCI_INT_RHPORT_STATUS_CHANGE_MASK |
      OHCI_INT_MASTER_ENABLE_MASK;

  OHCI_REG->control |= OHCI_CONTROL_CONTROL_BULK_RATIO | OHCI_CONTROL_LIST_CONTROL_ENABLE_MASK |
       OHCI_CONTROL_LIST_BULK_ENABLE_MASK | OHCI_CONTROL_LIST_PERIODIC_ENABLE_MASK; // TODO Isochronous

  OHCI_REG->frame_interval = (OHCI_FMINTERVAL_FSMPS << 16) | OHCI_FMINTERVAL_FI;
  OHCI_REG->periodic_start = (OHCI_FMINTERVAL_FI * 9) / 10; // Periodic start is 90% of frame interval

  OHCI_REG->control_bit.hc_functional_state = OHCI_CONTROL_FUNCSTATE_OPERATIONAL; // make HC's state to operational state TODO use this to suspend (save power)
  OHCI_REG->rh_status_bit.local_power_status_change = 1; // set global power for ports

  return true;
}

uint32_t hcd_uframe_number(uint8_t rhport)
{
  (void) rhport;
  return (ohci_data.frame_number_hi << 16 | OHCI_REG->frame_number) << 3;
}


//--------------------------------------------------------------------+
// PORT API
//--------------------------------------------------------------------+
void hcd_port_reset(uint8_t hostid)
{
  (void) hostid;
  OHCI_REG->rhport_status[0] = OHCI_RHPORT_PORT_RESET_STATUS_MASK;
}

bool hcd_port_connect_status(uint8_t hostid)
{
  (void) hostid;
  return OHCI_REG->rhport_status_bit[0].current_connect_status;
}

tusb_speed_t hcd_port_speed_get(uint8_t hostid)
{
  (void) hostid;
  return OHCI_REG->rhport_status_bit[0].low_speed_device_attached ? TUSB_SPEED_LOW : TUSB_SPEED_FULL;
}

// endpoints are tied to an address, which only reclaim after a long delay when enumerating
// thus there is no need to make sure ED is not in HC's cahed as it will not for sure
void hcd_device_close(uint8_t rhport, uint8_t dev_addr)
{
  // TODO OHCI
  (void) rhport;

  // addr0 serves as static head --> only set skip bit
  if ( dev_addr == 0 )
  {
    ohci_data.control[0].ed.skip = 1;
  }else
  {
    // remove control
    ed_list_remove_by_addr( p_ed_head[TUSB_XFER_CONTROL], dev_addr);

    // remove bulk
    ed_list_remove_by_addr(p_ed_head[TUSB_XFER_BULK], dev_addr);

    // remove interrupt
    ed_list_remove_by_addr(p_ed_head[TUSB_XFER_INTERRUPT], dev_addr);

    // TODO remove ISO
  }
}

//--------------------------------------------------------------------+
// Controller API
//--------------------------------------------------------------------+

//--------------------------------------------------------------------+
// CONTROL PIPE API
//--------------------------------------------------------------------+
static inline tusb_xfer_type_t ed_get_xfer_type(ohci_ed_t const * const p_ed)
{
  return (p_ed->ep_number == 0 ) ? TUSB_XFER_CONTROL     :
         (p_ed->is_iso               ) ? TUSB_XFER_ISOCHRONOUS :
         (p_ed->is_interrupt_xfer    ) ? TUSB_XFER_INTERRUPT   : TUSB_XFER_BULK;
}

static void ed_init(ohci_ed_t *p_ed, uint8_t dev_addr, uint16_t max_packet_size, uint8_t endpoint_addr, uint8_t xfer_type, uint8_t interval)
{
  (void) interval;

  // address 0 is used as async head, which always on the list --> cannot be cleared
  if (dev_addr != 0)
  {
    tu_memclr(p_ed, sizeof(ohci_ed_t));
  }

  p_ed->dev_addr    = dev_addr;
  p_ed->ep_number   = endpoint_addr & 0x0F;
  p_ed->pid         = (xfer_type == TUSB_XFER_CONTROL) ? OHCI_PID_SETUP : ( (endpoint_addr & TUSB_DIR_IN_MASK) ? OHCI_PID_IN : OHCI_PID_OUT );
  p_ed->speed             = _usbh_devices[dev_addr].speed;
  p_ed->is_iso            = (xfer_type == TUSB_XFER_ISOCHRONOUS) ? 1 : 0;
  p_ed->max_packet_size  = max_packet_size;

  p_ed->used              = 1;
  p_ed->is_interrupt_xfer = (xfer_type == TUSB_XFER_INTERRUPT ? 1 : 0);
}

static void gtd_init(ohci_gtd_t* p_td, void* data_ptr, uint16_t total_bytes)
{
  tu_memclr(p_td, sizeof(ohci_gtd_t));

  p_td->used                   = 1;
  p_td->expected_bytes         = total_bytes;

  p_td->buffer_rounding        = 1; // less than queued length is not a error
  p_td->delay_interrupt        = OHCI_INT_ON_COMPLETE_NO;
  p_td->condition_code         = OHCI_CCODE_NOT_ACCESSED;

  p_td->current_buffer_pointer = data_ptr;
  p_td->buffer_end             = total_bytes ? (((uint8_t*) data_ptr) + total_bytes-1) : NULL;
}

bool hcd_setup_send(uint8_t rhport, uint8_t dev_addr, uint8_t const setup_packet[8])
{
  (void) rhport;

  ohci_ed_t* p_ed = &ohci_data.control[dev_addr].ed;
  ohci_gtd_t *p_setup  = &ohci_data.control[dev_addr].gtd;

  gtd_init(p_setup, (void*) setup_packet, 8);
  p_setup->index       = dev_addr;
  p_setup->pid         = OHCI_PID_SETUP;
  p_setup->data_toggle = TU_BIN8(10); // DATA0
  p_setup->delay_interrupt = OHCI_INT_ON_COMPLETE_YES;

  //------------- Attach TDs list to Control Endpoint -------------//
  p_ed->td_head.address = (uint32_t) p_setup;

  OHCI_REG->command_status_bit.control_list_filled = 1;

  return true;
}

bool hcd_edpt_xfer(uint8_t rhport, uint8_t dev_addr, uint8_t ep_addr, uint8_t * buffer, uint16_t buflen)
{
  (void) rhport;

  uint8_t const epnum = tu_edpt_number(ep_addr);
  uint8_t const dir   = tu_edpt_dir(ep_addr);

  // FIXME control only for now
  if ( epnum == 0 )
  {
    ohci_ed_t* const p_ed = &ohci_data.control[dev_addr].ed;
    ohci_gtd_t *p_data  = &ohci_data.control[dev_addr].gtd;

    gtd_init(p_data, buffer, buflen);

    p_data->index       = dev_addr;
    p_data->pid         = dir ? OHCI_PID_IN : OHCI_PID_OUT;
    p_data->data_toggle = TU_BIN8(11); // DATA1
    p_data->delay_interrupt = OHCI_INT_ON_COMPLETE_YES;

    p_ed->td_head.address = (uint32_t) p_data;

    OHCI_REG->command_status_bit.control_list_filled = 1;
  }

  return true;
}

//--------------------------------------------------------------------+
// BULK/INT/ISO PIPE API
//--------------------------------------------------------------------+
static inline ohci_ed_t * ed_from_addr(uint8_t dev_addr, uint8_t ep_addr)
{
  if ( tu_edpt_number(ep_addr) == 0 ) return &ohci_data.control[dev_addr].ed;

  ohci_ed_t* ed_pool = ohci_data.ed_pool;

  for(uint32_t i=0; i<HCD_MAX_ENDPOINT; i++)
  {
    if ( (ed_pool[i].dev_addr == dev_addr) &&
          ep_addr == tu_edpt_addr(ed_pool[i].ep_number, ed_pool[i].pid == OHCI_PID_IN) )
    {
      return &ed_pool[i];
    }
  }

  return NULL;
}

static inline ohci_ed_t * ed_find_free(void)
{
  ohci_ed_t* ed_pool = ohci_data.ed_pool;

  for(uint8_t i = 0; i < HCD_MAX_ENDPOINT; i++)
  {
    if ( !ed_pool[i].used ) return &ed_pool[i];
  }

  return NULL;
}

static void ed_list_insert(ohci_ed_t * p_pre, ohci_ed_t * p_ed)
{
  p_ed->next = p_pre->next;
  p_pre->next = (uint32_t) p_ed;
}

static void ed_list_remove_by_addr(ohci_ed_t * p_head, uint8_t dev_addr)
{
  ohci_ed_t* p_prev = p_head;

  while( p_prev->next )
  {
    ohci_ed_t* ed = (ohci_ed_t*) p_prev->next;

    if (ed->dev_addr == dev_addr)
    {
      // unlink ed
      p_prev->next = ed->next;

      // point the removed ED's next pointer to list head to make sure HC can always safely move away from this ED
      ed->next = (uint32_t) p_head;
      ed->used = 0;
    }

    // check next valid since we could remove it
    if (p_prev->next) p_prev = (ohci_ed_t*) p_prev->next;
  }
}

bool hcd_edpt_open(uint8_t rhport, uint8_t dev_addr, tusb_desc_endpoint_t const * ep_desc)
{
  (void) rhport; 

  // TODO iso support
  TU_ASSERT(ep_desc->bmAttributes.xfer != TUSB_XFER_ISOCHRONOUS);

  //------------- Prepare Queue Head -------------//
  ohci_ed_t * p_ed;

  if ( ep_desc->bEndpointAddress == 0 )
  {
    p_ed = &ohci_data.control[dev_addr].ed;
  }else
  {
    p_ed = ed_find_free();
  }
  TU_ASSERT(p_ed);

  ed_init( p_ed, dev_addr, ep_desc->wMaxPacketSize.size, ep_desc->bEndpointAddress,
            ep_desc->bmAttributes.xfer, ep_desc->bInterval );

  // control of dev0 is used as static async head
  if ( dev_addr == 0 )
  {
    p_ed->skip = 0; // only need to clear skip bit
    return true;
  }

  ed_list_insert( p_ed_head[ep_desc->bmAttributes.xfer], p_ed );

  return true;
}

static ohci_gtd_t * gtd_find_free(void)
{
  for(uint8_t i=0; i < HCD_MAX_XFER; i++)
  {
    if ( !ohci_data.gtd_pool[i].used ) return &ohci_data.gtd_pool[i];
  }

  return NULL;
}

static void td_insert_to_ed(ohci_ed_t* p_ed, ohci_gtd_t * p_gtd)
{
  // tail is always NULL
  if ( tu_align16(p_ed->td_head.address) == 0 )
  { // TD queue is empty --> head = TD
    p_ed->td_head.address |= (uint32_t) p_gtd;
  }
  else
  { // TODO currently only support queue up to 2 TD each endpoint at a time
    ((ohci_gtd_t*) tu_align16(p_ed->td_head.address))->next = (uint32_t) p_gtd;
  }
}

static bool pipe_queue_xfer(uint8_t dev_addr, uint8_t ep_addr, uint8_t buffer[], uint16_t total_bytes, bool int_on_complete)
{
  ohci_ed_t* const p_ed = ed_from_addr(dev_addr, ep_addr);

  // not support ISO yet
  TU_VERIFY ( !p_ed->is_iso );

  ohci_gtd_t * const p_gtd = gtd_find_free();
  TU_ASSERT(p_gtd); // not enough gtd

  gtd_init(p_gtd, buffer, total_bytes);
  p_gtd->index = p_ed-ohci_data.ed_pool;

  if ( int_on_complete )  p_gtd->delay_interrupt = OHCI_INT_ON_COMPLETE_YES;

  td_insert_to_ed(p_ed, p_gtd);

  return true;
}

bool hcd_pipe_queue_xfer(uint8_t dev_addr, uint8_t ep_addr, uint8_t buffer[], uint16_t total_bytes)
{
  return pipe_queue_xfer(dev_addr, ep_addr, buffer, total_bytes, false);
}

bool  hcd_pipe_xfer(uint8_t dev_addr, uint8_t ep_addr, uint8_t buffer[], uint16_t total_bytes, bool int_on_complete)
{
  (void) int_on_complete;
  TU_ASSERT( pipe_queue_xfer(dev_addr, ep_addr, buffer, total_bytes, true) );

  tusb_xfer_type_t xfer_type = ed_get_xfer_type( ed_from_addr(dev_addr, ep_addr) );

  if (TUSB_XFER_BULK == xfer_type) OHCI_REG->command_status_bit.bulk_list_filled = 1;

  return true;
}

bool hcd_edpt_busy(uint8_t dev_addr, uint8_t ep_addr)
{
  ohci_ed_t const * const p_ed = ed_from_addr(dev_addr, ep_addr);
  return tu_align16(p_ed->td_head.address) != tu_align16(p_ed->td_tail);
}

bool hcd_edpt_stalled(uint8_t dev_addr, uint8_t ep_addr)
{
  ohci_ed_t const * const p_ed = ed_from_addr(dev_addr, ep_addr);
  return p_ed->td_head.halted && p_ed->is_stalled;
}

bool hcd_edpt_clear_stall(uint8_t dev_addr, uint8_t ep_addr)
{
  ohci_ed_t * const p_ed = ed_from_addr(dev_addr, ep_addr);

  p_ed->is_stalled = 0;
  p_ed->td_tail    &= 0x0Ful; // set tail pointer back to NULL

  p_ed->td_head.toggle = 0; // reset data toggle
  p_ed->td_head.halted = 0;

  if ( TUSB_XFER_BULK == ed_get_xfer_type(p_ed) ) OHCI_REG->command_status_bit.bulk_list_filled = 1;

  return true;
}


//--------------------------------------------------------------------+
// OHCI Interrupt Handler
//--------------------------------------------------------------------+
static ohci_td_item_t* list_reverse(ohci_td_item_t* td_head)
{
  ohci_td_item_t* td_reverse_head = NULL;

  while(td_head != NULL)
  {
    uint32_t next = td_head->next;

    // make current's item become reverse's first item
    td_head->next = (uint32_t) td_reverse_head;
    td_reverse_head  = td_head;

    td_head = (ohci_td_item_t*) next; // advance to next item
  }

  return td_reverse_head;
}

static inline bool gtd_is_control(ohci_gtd_t const * const p_qtd)
{
  return ((uint32_t) p_qtd) < ((uint32_t) ohci_data.gtd_pool); // check ohci_data_t for memory layout
}

static inline ohci_ed_t* gtd_get_ed(ohci_gtd_t const * const p_qtd)
{
  if ( gtd_is_control(p_qtd) )
  {
    return &ohci_data.control[p_qtd->index].ed;
  }else
  {
    return &ohci_data.ed_pool[p_qtd->index];
  }
}

static inline uint32_t gtd_xfer_byte_left(uint32_t buffer_end, uint32_t current_buffer)
{ // 5.2.9 OHCI sample code
  return (tu_align4k(buffer_end ^ current_buffer) ? 0x1000 : 0) +
      tu_offset4k(buffer_end) - tu_offset4k(current_buffer) + 1;
}

static void done_queue_isr(uint8_t hostid)
{
  (void) hostid;

  // done head is written in reversed order of completion --> need to reverse the done queue first
  ohci_td_item_t* td_head = list_reverse ( (ohci_td_item_t*) tu_align16(ohci_data.hcca.done_head) );

  while( td_head != NULL )
  {
    // TODO check if td_head is iso td
    //------------- Non ISO transfer -------------//
    ohci_gtd_t * const p_qtd = (ohci_gtd_t *) td_head;
    xfer_result_t const event = (p_qtd->condition_code == OHCI_CCODE_NO_ERROR) ? XFER_RESULT_SUCCESS :
                                (p_qtd->condition_code == OHCI_CCODE_STALL) ? XFER_RESULT_STALLED : XFER_RESULT_FAILED;

    p_qtd->used = 0; // free TD
    if ( (p_qtd->delay_interrupt == OHCI_INT_ON_COMPLETE_YES) || (event != XFER_RESULT_SUCCESS) )
    {
      ohci_ed_t * const p_ed  = gtd_get_ed(p_qtd);

      uint32_t const xferred_bytes = p_qtd->expected_bytes - gtd_xfer_byte_left((uint32_t) p_qtd->buffer_end, (uint32_t) p_qtd->current_buffer_pointer);

      // NOTE Assuming the current list is BULK and there is no other EDs in the list has queued TDs.
      // When there is a error resulting this ED is halted, and this EP still has other queued TD
      // --> the Bulk list only has this halted EP queueing TDs (remaining)
      // --> Bulk list will be considered as not empty by HC !!! while there is no attempt transaction on this list
      // --> HC will not process Control list (due to service ratio when Bulk list not empty)
      // To walk-around this, the halted ED will have TailP = HeadP (empty list condition), when clearing halt
      // the TailP must be set back to NULL for processing remaining TDs
      if ((event != XFER_RESULT_SUCCESS))
      {
        p_ed->td_tail &= 0x0Ful;
        p_ed->td_tail |= tu_align16(p_ed->td_head.address); // mark halted EP as empty queue
        if ( event == XFER_RESULT_STALLED ) p_ed->is_stalled = 1;
      }

      hcd_event_xfer_complete(p_ed->dev_addr,
                              tu_edpt_addr(p_ed->ep_number, p_ed->pid == OHCI_PID_IN),
                              event, xferred_bytes);
    }

    td_head = (ohci_td_item_t*) td_head->next;
  }
}

void hcd_int_handler(uint8_t hostid)
{
  uint32_t const int_en     = OHCI_REG->interrupt_enable;
  uint32_t const int_status = OHCI_REG->interrupt_status & int_en;

  if (int_status == 0) return;

  // Frame number overflow
  if ( int_status & OHCI_INT_FRAME_OVERFLOW_MASK )
  {
    ohci_data.frame_number_hi++;
  }

  //------------- RootHub status -------------//
  if ( int_status & OHCI_INT_RHPORT_STATUS_CHANGE_MASK )
  {
    uint32_t const rhport_status = OHCI_REG->rhport_status[0] & OHCI_RHPORT_ALL_CHANGE_MASK;

    // TODO dual port is not yet supported
    if ( rhport_status & OHCI_RHPORT_CONNECT_STATUS_CHANGE_MASK )
    {
      // TODO check if remote wake-up
      if ( OHCI_REG->rhport_status_bit[0].current_connect_status )
      {
        // TODO reset port immediately, without this controller will got 2-3 (debouncing connection status change)
        OHCI_REG->rhport_status[0] = OHCI_RHPORT_PORT_RESET_STATUS_MASK;
        hcd_event_device_attach(0);
      }else
      {
        hcd_event_device_remove(0);
      }
    }

    if ( rhport_status & OHCI_RHPORT_PORT_SUSPEND_CHANGE_MASK)
    {

    }

    OHCI_REG->rhport_status[0] = rhport_status; // acknowledge all interrupt
  }

  //------------- Transfer Complete -------------//
  if ( int_status & OHCI_INT_WRITEBACK_DONEHEAD_MASK)
  {
    done_queue_isr(hostid);
  }

  OHCI_REG->interrupt_status = int_status; // Acknowledge handled interrupt
}
//--------------------------------------------------------------------+
// HELPER
//--------------------------------------------------------------------+


#endif