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                         /** Mask for determining the type of an endpoint from an endpoint descriptor. This should then be compared
  56                          *  with the EP_TYPE_* masks to determine the exact type of the endpoint.
  57                          */
  58                         #define EP_TYPE_MASK                       0x03
  59
  60                         /** Casts a pointer to a descriptor inside the configuration descriptor into a pointer to the given
  61                          *  descriptor type.
  62                          *
  63                          *  Usage Example:
  64                          *  \code
  65                          *  uint8_t* CurrDescriptor = &ConfigDescriptor[0]; // Pointing to the configuration header
  66                          *  USB_Descriptor_Configuration_Header_t* ConfigHeaderPtr = DESCRIPTOR_PCAST(CurrDescriptor,
  67                          *                                                           USB_Descriptor_Configuration_Header_t);
  68                          *
  69                          *  // Can now access elements of the configuration header struct using the -> indirection operator
  70                          *  \endcode
  71                          */
  72                         #define DESCRIPTOR_PCAST(DescriptorPtr, Type) ((Type*)DescriptorPtr)
  73
  74                         /** Casts a pointer to a descriptor inside the configuration descriptor into the given descriptor
  75                          *  type (as an actual struct instance rather than a pointer to a struct).
  76                          *
  77                          *  Usage Example:
  78                          *  \code
  79                          *  uint8_t* CurrDescriptor = &ConfigDescriptor[0]; // Pointing to the configuration header
  80                          *  USB_Descriptor_Configuration_Header_t ConfigHeader = DESCRIPTOR_CAST(CurrDescriptor,
  81                          *                                                       USB_Descriptor_Configuration_Header_t);
  82                          *
  83                          *  // Can now access elements of the configuration header struct using the . operator
  84                          *  \endcode
  85                          */
  86                         #define DESCRIPTOR_CAST(DescriptorPtr, Type)  (*DESCRIPTOR_PCAST(DescriptorPtr, Type))
  87
  88                         /** Returns the descriptor's type, expressed as the 8-bit type value in the header of the descriptor.
  89                          *  This value's meaning depends on the descriptor's placement in the descriptor, but standard type
  90                          *  values can be accessed in the DescriptorTypes_t enum located in USB/HighLevel/StdDescriptors.h.
  91                          */
  92                         #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES) || defined(__DOXYGEN__)
  93                                 #define DESCRIPTOR_TYPE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).Type
  94                         #else
  95                                 #define DESCRIPTOR_TYPE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).bDescriptorType
  96                         #endif
  97
  98                         /** Returns the descriptor's size, expressed as the 8-bit value indicating the number of bytes. */
  99                         #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES) || defined(__DOXYGEN__)
 100                                 #define DESCRIPTOR_SIZE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).Size
 101                         #else
 102                                 #define DESCRIPTOR_SIZE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).bLength
 103                         #endif
 104
 105                         /** Creates a prototype for or begins a descriptor comparator routine. Descriptor comparator routines are
 106                          *  small search routines which are passed a pointer to the current sub descriptor in the configuration
 107                          *  descriptor, and which analyse the sub descriptor to determine whether or not it matches the routine's
 108                          *  search parameters. Comparator routines provide a powerful way to scan through the config descriptor
 109                          *  for certain descriptors matching unique criteria.
 110                          *
 111                          *  Comparator routines are passed in a single pointer named CurrentDescriptor, and should return a value
 112                          *  of a member of the DSEARCH_Return_ErrorCodes_t enum.
 113                          */
 114                         #define DESCRIPTOR_COMPARATOR(name)           uint8_t DCOMP_##name (void* const CurrentDescriptor)
 115
 116                         /** Searches for the next descriptor in the given configuration descriptor using a premade comparator
 117                          *  function. The routine updates the position and remaining configuration descriptor bytes values
 118                          *  automatically. If a comparator routine fails a search, the descriptor pointer is retreated back
 119                          *  so that the next descriptor search invocation will start from the descriptor which first caused the
 120                          *  original search to fail. This behaviour allows for one comparator to be used immediately after another
 121                          *  has failed, starting the second search from the descriptor which failed the first.
 122                          *
 123                          *  \param DSize    Pointer to an int storing the remaining bytes in the configuration descriptor
 124                          *  \param DPos     Pointer to the current position in the configuration descriptor
 125                          *  \param DSearch  Name of the comparator search function to use on the configuration descriptor
 126                          *
 127                          *  \return Value of one of the members of the DSEARCH_Comp_Return_ErrorCodes_t enum
 128                          *
 129                          *  Usage Example:
 130                          *  \code
 131                          *  DESCRIPTOR_COMPARATOR(EndpointSearcher); // Comparator Prototype
 132                          *
 133                          *  DESCRIPTOR_COMPARATOR(EndpointSearcher)
 134                          *  {
 135                          *     if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 136                          *         return Descriptor_Search_Found;
 137                          *     else
 138                          *         return Descriptor_Search_NotFound;
 139                          *  }
 140                          *
 141                          *  //...
 142                          *  // After retrieving configuration descriptor:
 143                          *  if (USB_Host_GetNextDescriptorComp(&BytesRemaining, &ConfigDescriptorData, EndpointSearcher) ==
 144                          *      Descriptor_Search_Comp_Found)
 145                          *  {
 146                          *      // Do something with the endpoint descriptor
 147                          *  }
 148                          *  \endcode
 149                          */
 150                         #define USB_Host_GetNextDescriptorComp(DSize, DPos, DSearch) \
 151                                                                       USB_Host_GetNextDescriptorComp_P(DSize, DPos, DCOMP_##DSearch)
 152                 /* Enums: */
 153                         /** Enum for return values of a descriptor comparator made with DESCRIPTOR_COMPARATOR. */
 154                         enum DSEARCH_Return_ErrorCodes_t
 155                         {
 156                                 Descriptor_Search_Found                = 0, /**< Current descriptor matches comparator criteria. */
 157                                 Descriptor_Search_Fail                 = 1, /**< No further descriptor could possibly match criteria, fail the search. */
 158                                 Descriptor_Search_NotFound             = 2, /**< Current descriptor does not match comparator criteria. */
 159                         };
 160
 161                         /** Enum for return values of USB_Host_GetNextDescriptorComp() */
 162                         enum DSEARCH_Comp_Return_ErrorCodes_t
 163                         {
 164                                 Descriptor_Search_Comp_Found           = 0, /**< Configuration descriptor now points to descriptor which matches
 165                                                                              *   search criteria of the given comparator function. */
 166                                 Descriptor_Search_Comp_Fail            = 1, /**< Comparator function returned Descriptor_Search_Fail. */
 167                                 Descriptor_Search_Comp_EndOfDescriptor = 2, /**< End of configuration descriptor reached before match found. */
 168                         };
 169
 170                 /* Function Prototypes: */
 171                         /** Retrieves the configuration descriptor data or size from an attached device via a standard request.
 172                          *
 173                          *  \param ConfigSizePtr  Pointer to a uint16_t for either storing or retrieving the configuration
 174                          *         descriptor size
 175                          *
 176                          *  \param BufferPtr  Pointer to the buffer for storing the configuration descriptor data. If this is
 177                          *                    NULL, the size of the configuration descriptor will be retrieved instead and
 178                          *                    placed in the variable pointed to by ConfigSizePtr. If this is non-NULL, the number
 179                          *                    of bytes indicated by ConfigSizePtr of the configuration descriptor will be loaded
 180                          *                    into the buffer
 181                          */
 182                         uint8_t USB_Host_GetDeviceConfigDescriptor(uint16_t* const ConfigSizePtr, void* BufferPtr)
 183                                                                    ATTR_NON_NULL_PTR_ARG(1);
 184
 185                 /* Inline Functions: */
 186                         /** Skips over the current sub-descriptor inside the configuration descriptor, so that the pointer then
 187                             points to the next sub-descriptor. The bytes remaining value is automatically decremented.
 188                          *
 189                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 190                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 191                          */
 192                         static inline void USB_Host_GetNextDescriptor(uint16_t* const BytesRem,
 193                                                                       uint8_t** const CurrConfigLoc)
 194                                                                                                                   ATTR_NON_NULL_PTR_ARG(1, 2);
 195                         static inline void USB_Host_GetNextDescriptor(uint16_t* const BytesRem,
 196                                                                       uint8_t** const CurrConfigLoc)
 197                         {
 198                                 #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES)
 199                                 uint16_t CurrDescriptorSize = DESCRIPTOR_CAST(*CurrConfigLoc, USB_Descriptor_Header_t).Size;
 200                                 #else
 201                                 uint16_t CurrDescriptorSize = DESCRIPTOR_CAST(*CurrConfigLoc, USB_Descriptor_Header_t).bLength;
 202                                 #endif
 203
 204                                 *CurrConfigLoc += CurrDescriptorSize;
 205                                 *BytesRem      -= CurrDescriptorSize;
 206                         }
 207
 208                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value.
 209                          *  The bytes remaining value is automatically decremented.
 210                          *
 211                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 212                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 213                          * \param Type  Descriptor type value to search for
 214                          */
 215                         void USB_Host_GetNextDescriptorOfType(uint16_t* const BytesRem,
 216                                                               uint8_t** const CurrConfigLoc,
 217                                                               const uint8_t Type)
 218                                                               ATTR_NON_NULL_PTR_ARG(1, 2);
 219
 220                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value,
 221                          *  which must come before a descriptor of the second given type value. If the BeforeType type
 222                          *  descriptor is reached first, the number of bytes remaining to process is set to zero and the
 223                          *  function exits. The bytes remaining value is automatically decremented.
 224                          *
 225                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 226                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 227                          * \param Type  Descriptor type value to search for
 228                          * \param BeforeType  Descriptor type value which must not be reached before the given Type descriptor
 229                          */
 230                         void USB_Host_GetNextDescriptorOfTypeBefore(uint16_t* const BytesRem,
 231                                                                     uint8_t** const CurrConfigLoc,
 232                                                                     const uint8_t Type,
 233                                                                     const uint8_t BeforeType)
 234                                                                     ATTR_NON_NULL_PTR_ARG(1, 2);
 235
 236                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value,
 237                          *  which must come after a descriptor of the second given type value. The bytes remaining value is
 238                          *  automatically decremented.
 239                          *
 240                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 241                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 242                          * \param Type  Descriptor type value to search for
 243                          * \param AfterType  Descriptor type value which must be reached before the given Type descriptor
 244                          */
 245                         void USB_Host_GetNextDescriptorOfTypeAfter(uint16_t* const BytesRem,
 246                                                                    uint8_t** const CurrConfigLoc,
 247                                                                    const uint8_t Type,
 248                                                                    const uint8_t AfterType)
 249                                                                    ATTR_NON_NULL_PTR_ARG(1, 2);
 250
 251         /* Private Interface - For use in library only: */
 252         #if !defined(__DOXYGEN__)
 253                 /* Function Prototypes: */
 254                         uint8_t USB_Host_GetNextDescriptorComp_P(uint16_t* BytesRem, uint8_t** CurrConfigLoc,
 255                                                      uint8_t (* const ComparatorRoutine)(void* const));
 256         #endif
 257
 258         /* Disable C linkage for C++ Compilers: */
 259                 #if defined(__cplusplus)
 260                         }
 261                 #endif
 262
 263 #endif