LUFA/Drivers/USB/Class/ConfigDescriptor.h

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 /** \file
  32  *
  33  *  Configuration descriptor parser API. This section of the library gives a friendly API which can be used in
  34  *  host applications to easily parse an attached device's configuration descriptor so that endpoint, interface
  35  *  and other descriptor data can be extracted and used as needed.
  36  */
  37
  38 #ifndef __CONFIGDESCRIPTOR_H__
  39 #define __CONFIGDESCRIPTOR_H__
  40
  41         /* Includes: */
  42                 #include <avr/io.h>
  43
  44                 #include "../../../Common/Common.h"
  45                 #include "../LowLevel/HostChapter9.h"
  46                 #include "../HighLevel/StdDescriptors.h"
  47
  48         /* Enable C linkage for C++ Compilers: */
  49                 #if defined(__cplusplus)
  50                         extern "C" {
  51                 #endif
  52
  53         /* Public Interface - May be used in end-application: */
  54                 /* Macros: */
  55                         /** Casts a pointer to a descriptor inside the configuration descriptor into a pointer to the given
  56                          *  descriptor type.
  57                          *
  58                          *  Usage Example:
  59                          *  \code
  60                          *  uint8_t* CurrDescriptor = &ConfigDescriptor[0]; // Pointing to the configuration header
  61                          *  USB_Descriptor_Configuration_Header_t* ConfigHeaderPtr = DESCRIPTOR_PCAST(CurrDescriptor,
  62                          *                                                           USB_Descriptor_Configuration_Header_t);
  63                          *
  64                          *  // Can now access elements of the configuration header struct using the -> indirection operator
  65                          *  \endcode
  66                          */
  67                         #define DESCRIPTOR_PCAST(DescriptorPtr, Type) ((Type*)DescriptorPtr)
  68
  69                         /** Casts a pointer to a descriptor inside the configuration descriptor into the given descriptor
  70                          *  type (as an actual struct instance rather than a pointer to a struct).
  71                          *
  72                          *  Usage Example:
  73                          *  \code
  74                          *  uint8_t* CurrDescriptor = &ConfigDescriptor[0]; // Pointing to the configuration header
  75                          *  USB_Descriptor_Configuration_Header_t ConfigHeader = DESCRIPTOR_CAST(CurrDescriptor,
  76                          *                                                       USB_Descriptor_Configuration_Header_t);
  77                          *
  78                          *  // Can now access elements of the configuration header struct using the . operator
  79                          *  \endcode
  80                          */
  81                         #define DESCRIPTOR_CAST(DescriptorPtr, Type)  (*DESCRIPTOR_PCAST(DescriptorPtr, Type))
  82
  83                         /** Returns the descriptor's type, expressed as the 8-bit type value in the header of the descriptor.
  84                          *  This value's meaning depends on the descriptor's placement in the descriptor, but standard type
  85                          *  values can be accessed in the DescriptorTypes_t enum located in USB/HighLevel/StdDescriptors.h.
  86                          */
  87                         #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES) || defined(__DOXYGEN__)
  88                                 #define DESCRIPTOR_TYPE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).Type
  89                         #else
  90                                 #define DESCRIPTOR_TYPE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).bDescriptorType
  91                         #endif
  92
  93                         /** Returns the descriptor's size, expressed as the 8-bit value indicating the number of bytes. */
  94                         #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES) || defined(__DOXYGEN__)
  95                                 #define DESCRIPTOR_SIZE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).Size
  96                         #else
  97                                 #define DESCRIPTOR_SIZE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).bLength
  98                         #endif
  99
 100                         /** Creates a prototype for or begins a descriptor comparitor routine. Descriptor comparitor routines are
 101                          *  small search routines which are passed a pointer to the current sub descriptor in the configuration
 102                          *  descriptor, and which analyse the sub descriptor to determine whether or not it matches the routine's
 103                          *  search parameters. Comparitor routines provide a powerful way to scan through the config descriptor
 104                          *  for certain descriptors matching unique criteria.
 105                          *
 106                          *  Comparitor routines are passed in a single pointer named CurrentDescriptor, and should return a value
 107                          *  of a member of the DSEARCH_Return_ErrorCodes_t enum.
 108                          */
 109                         #define DESCRIPTOR_COMPARATOR(name)           uint8_t DCOMP_##name (void* const CurrentDescriptor)
 110
 111                         /** Searches for the next descriptor in the given configuration descriptor using a premade comparator
 112                          *  function. The routine updates the position and remaining configuration descriptor bytes values
 113                          *  automatically. If a comparator routine fails a search, the descriptor pointer is retreated back
 114                          *  so that the next descriptor search invocation will start from the descriptor which first caused the
 115                          *  original search to fail. This behaviour allows for one comparator to be used immediately after another
 116                          *  has failed, starting the second search from the descriptor which failed the first.
 117                          *
 118                          *  \param DSize    Pointer to an int storing the remaining bytes in the configuration descriptor
 119                          *  \param DPos     Pointer to the current position in the configuration descriptor
 120                          *  \param DSearch  Name of the comparitor search function to use on the configuration descriptor
 121                          *
 122                          *  \return Value of one of the members of the DSEARCH_Comp_Return_ErrorCodes_t enum
 123                          *
 124                          *  Usage Example:
 125                          *  \code
 126                          *  DESCRIPTOR_COMPARATOR(EndpointSearcher); // Comparator Prototype
 127                          *
 128                          *  DESCRIPTOR_COMPARATOR(EndpointSearcher)
 129                          *  {
 130                          *     if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 131                          *         return Descriptor_Search_Found;
 132                          *     else
 133                          *         return Descriptor_Search_NotFound;
 134                          *  }
 135                          *
 136                          *  //...
 137                          *  // After retrieving configuration descriptor:
 138                          *  if (USB_Host_GetNextDescriptorComp(&BytesRemaining, &ConfigDescriptorData, EndpointSearcher) ==
 139                          *      Descriptor_Search_Comp_Found)
 140                          *  {
 141                          *      // Do something with the endpoint descriptor
 142                          *  }
 143                          *  \endcode
 144                          */
 145                         #define USB_Host_GetNextDescriptorComp(DSize, DPos, DSearch) \
 146                                                                       USB_Host_GetNextDescriptorComp_P(DSize, DPos, DCOMP_##DSearch)
 147                 /* Enums: */
 148                         /** Enum for return values of a descriptor comparator made with DESCRIPTOR_COMPARATOR. */
 149                         enum DSEARCH_Return_ErrorCodes_t
 150                         {
 151                                 Descriptor_Search_Found                = 0, /**< Current descriptor matches comparator criteria. */
 152                                 Descriptor_Search_Fail                 = 1, /**< No further descriptor could possibly match criteria, fail the search. */
 153                                 Descriptor_Search_NotFound             = 2, /**< Current descriptor does not match comparator criteria. */
 154                         };
 155
 156                         /** Enum for return values of USB_Host_GetNextDescriptorComp() */
 157                         enum DSEARCH_Comp_Return_ErrorCodes_t
 158                         {
 159                                 Descriptor_Search_Comp_Found           = 0, /**< Configuration descriptor now points to decriptor which matches
 160                                                                              *   search criteria of the given comparator function. */
 161                                 Descriptor_Search_Comp_Fail            = 1, /**< Comparator function returned Descriptor_Search_Fail. */
 162                                 Descriptor_Search_Comp_EndOfDescriptor = 2, /**< End of configuration descriptor reached before match found. */
 163                         };
 164
 165                 /* Function Prototypes: */
 166                         /** Retrieves the configuration descriptor data or size from an attached device via a standard request.
 167                          *
 168                          *  \param ConfigSizePtr  Pointer to a uint16_t for either storing or retrieving the configuration
 169                          *         descriptor size
 170                          *
 171                          *  \param BufferPtr  Pointer to the buffer for storing the configuration descriptor data. If this is
 172                          *                    NULL, the size of the configuration descriptor will be retrieved instead and
 173                          *                    placed in the variable pointed to by ConfigSizePtr. If this is non-NULL, the number
 174                          *                    of bytes indicated by ConfigSizePtr of the configuration descriptor will be loaded
 175                          *                    into the buffer
 176                          */
 177                         uint8_t USB_Host_GetDeviceConfigDescriptor(uint16_t* const ConfigSizePtr, void* BufferPtr)
 178                                                                    ATTR_NON_NULL_PTR_ARG(1);
 179
 180                 /* Inline Functions: */
 181                         /** Skips over the current sub-descriptor inside the configuration descriptor, so that the pointer then
 182                             points to the next sub-descriptor. The bytes remaining value is automatically decremented.
 183                          *
 184                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 185                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 186                          */
 187                         static inline void USB_Host_GetNextDescriptor(uint16_t* const BytesRem,
 188                                                                       uint8_t** const CurrConfigLoc)
 189                                                                                                                   ATTR_NON_NULL_PTR_ARG(1, 2);
 190                         static inline void USB_Host_GetNextDescriptor(uint16_t* const BytesRem,
 191                                                                       uint8_t** const CurrConfigLoc)
 192                         {
 193                                 #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES)
 194                                 uint16_t CurrDescriptorSize = DESCRIPTOR_CAST(*CurrConfigLoc, USB_Descriptor_Header_t).Size;
 195                                 #else
 196                                 uint16_t CurrDescriptorSize = DESCRIPTOR_CAST(*CurrConfigLoc, USB_Descriptor_Header_t).bLength;
 197                                 #endif
 198
 199                                 *CurrConfigLoc += CurrDescriptorSize;
 200                                 *BytesRem      -= CurrDescriptorSize;
 201                         }
 202
 203                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value.
 204                          *  The bytes remaining value is automatically decremented.
 205                          *
 206                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 207                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 208                          * \param Type  Descriptor type value to search for
 209                          */
 210                         void USB_Host_GetNextDescriptorOfType(uint16_t* const BytesRem,
 211                                                               uint8_t** const CurrConfigLoc,
 212                                                               const uint8_t Type)
 213                                                               ATTR_NON_NULL_PTR_ARG(1, 2);
 214
 215                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value,
 216                          *  which must come before a descriptor of the second given type value. If the BeforeType type
 217                          *  descriptor is reached first, the number of bytes remaining to process is set to zero and the
 218                          *  function exits. The bytes remaining value is automatically decremented.
 219                          *
 220                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 221                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 222                          * \param Type  Descriptor type value to search for
 223                          * \param BeforeType  Descriptor type value which must not be reached before the given Type descriptor
 224                          */
 225                         void USB_Host_GetNextDescriptorOfTypeBefore(uint16_t* const BytesRem,
 226                                                                     uint8_t** const CurrConfigLoc,
 227                                                                     const uint8_t Type,
 228                                                                     const uint8_t BeforeType)
 229                                                                     ATTR_NON_NULL_PTR_ARG(1, 2);
 230
 231                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value,
 232                          *  which must come after a descriptor of the second given type value. The bytes remaining value is
 233                          *  automatically decremented.
 234                          *
 235                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 236                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 237                          * \param Type  Descriptor type value to search for
 238                          * \param AfterType  Descriptor type value which must be reached before the given Type descriptor
 239                          */
 240                         void USB_Host_GetNextDescriptorOfTypeAfter(uint16_t* const BytesRem,
 241                                                                    uint8_t** const CurrConfigLoc,
 242                                                                    const uint8_t Type,
 243                                                                    const uint8_t AfterType)
 244                                                                    ATTR_NON_NULL_PTR_ARG(1, 2);
 245
 246         /* Private Interface - For use in library only: */
 247         #if !defined(__DOXYGEN__)
 248                 /* Function Prototypes: */
 249                         uint8_t USB_Host_GetNextDescriptorComp_P(uint16_t* BytesRem, uint8_t** CurrConfigLoc,
 250                                                      uint8_t (* const ComparatorRoutine)(void* const));
 251         #endif
 252
 253         /* Disable C linkage for C++ Compilers: */
 254                 #if defined(__cplusplus)
 255                         }
 256                 #endif
 257
 258 #endif