MouseHid.c

Go to the documentation of this file.

 
#include "UsbMouse.h"
 
UINT8 *
GetNextHidItem (
  IN  UINT8     *StartPos,
  IN  UINT8     *EndPos,
  OUT HID_ITEM  *HidItem
  )
{
  UINT8  Temp;
 
  if (EndPos <= StartPos) {
    return NULL;
  }
 
  Temp = *StartPos;
  StartPos++;
 
  //
  // Bit format of prefix byte:
  // Bits 0-1: Size
  // Bits 2-3: Type
  // Bits 4-7: Tag
  //
  HidItem->Type = BitFieldRead8 (Temp, 2, 3);
  HidItem->Tag  = BitFieldRead8 (Temp, 4, 7);
 
  if (HidItem->Tag == HID_ITEM_TAG_LONG) {
    //
    // Long Items are not supported, although we try to parse it.
    //
    HidItem->Format = HID_ITEM_FORMAT_LONG;
 
    if ((EndPos - StartPos) >= 2) {
      HidItem->Size = *StartPos++;
      HidItem->Tag  = *StartPos++;
 
      if ((EndPos - StartPos) >= HidItem->Size) {
        HidItem->Data.LongData = StartPos;
        StartPos              += HidItem->Size;
        return StartPos;
      }
    }
  } else {
    HidItem->Format = HID_ITEM_FORMAT_SHORT;
    HidItem->Size   = BitFieldRead8 (Temp, 0, 1);
 
    switch (HidItem->Size) {
      case 0:
        //
        // No data
        //
        return StartPos;
 
      case 1:
        //
        // 1-byte data
        //
        if ((EndPos - StartPos) >= 1) {
          HidItem->Data.Uint8 = *StartPos++;
          return StartPos;
        }
 
      case 2:
        //
        // 2-byte data
        //
        if ((EndPos - StartPos) >= 2) {
          CopyMem (&HidItem->Data.Uint16, StartPos, sizeof (UINT16));
          StartPos += 2;
          return StartPos;
        }
 
      case 3:
        //
        // 4-byte data, adjust size
        //
        HidItem->Size = 4;
        if ((EndPos - StartPos) >= 4) {
          CopyMem (&HidItem->Data.Uint32, StartPos, sizeof (UINT32));
          StartPos += 4;
          return StartPos;
        }
    }
  }
 
  return NULL;
}
 
UINT32
GetItemData (
  IN  HID_ITEM  *HidItem
  )
{
  //
  // Get data from HID item.
  //
  switch (HidItem->Size) {
    case 1:
      return HidItem->Data.Uint8;
    case 2:
      return HidItem->Data.Uint16;
    case 4:
      return HidItem->Data.Uint32;
  }
 
  return 0;
}
 
VOID
ParseHidItem (
  IN  USB_MOUSE_DEV  *UsbMouse,
  IN  HID_ITEM       *HidItem
  )
{
  UINT8  Data;
 
  switch (HidItem->Type) {
    case HID_ITEM_TYPE_MAIN:
      //
      // we don't care any main items, just skip
      //
      return;
 
    case HID_ITEM_TYPE_GLOBAL:
      //
      // For global items, we only care Usage Page tag for Button Page here
      //
      if (HidItem->Tag == HID_GLOBAL_ITEM_TAG_USAGE_PAGE) {
        Data = (UINT8)GetItemData (HidItem);
        if (Data == 0x09) {
          //
          // Button Page
          //
          UsbMouse->PrivateData.ButtonDetected = TRUE;
        }
      }
 
      return;
 
    case HID_ITEM_TYPE_LOCAL:
      if (HidItem->Size == 0) {
        //
        // No expected data for local item
        //
        return;
      }
 
      Data = (UINT8)GetItemData (HidItem);
 
      switch (HidItem->Tag) {
        case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
          if (UsbMouse->PrivateData.ButtonDetected) {
            UsbMouse->PrivateData.ButtonMinIndex = Data;
          }
 
          return;
 
        case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
        {
          if (UsbMouse->PrivateData.ButtonDetected) {
            UsbMouse->PrivateData.ButtonMaxIndex = Data;
          }
 
          return;
        }
 
        default:
          return;
      }
  }
}
 
EFI_STATUS
ParseMouseReportDescriptor (
  OUT USB_MOUSE_DEV  *UsbMouse,
  IN  UINT8          *ReportDescriptor,
  IN  UINTN          ReportSize
  )
{
  UINT8     *DescriptorEnd;
  UINT8     *Ptr;
  HID_ITEM  HidItem;
 
  DescriptorEnd = ReportDescriptor + ReportSize;
 
  Ptr = GetNextHidItem (ReportDescriptor, DescriptorEnd, &HidItem);
  while (Ptr != NULL) {
    if (HidItem.Format != HID_ITEM_FORMAT_SHORT) {
      //
      // Long Item is not supported at current HID revision
      //
      return EFI_UNSUPPORTED;
    }
 
    ParseHidItem (UsbMouse, &HidItem);
 
    Ptr = GetNextHidItem (Ptr, DescriptorEnd, &HidItem);
  }
 
  UsbMouse->NumberOfButtons = (UINT8)(UsbMouse->PrivateData.ButtonMaxIndex - UsbMouse->PrivateData.ButtonMinIndex + 1);
  UsbMouse->XLogicMax       = 127;
  UsbMouse->YLogicMax       = 127;
  UsbMouse->XLogicMin       = -127;
  UsbMouse->YLogicMin       = -127;
 
  return EFI_SUCCESS;
}