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 /** \ingroup Group_Descriptors
  39  *  @defgroup Group_ConfigDescriptorParser Configuration Descriptor Parser
  40  *
  41  *  Functions, macros, variables, enums and types related to the parsing of Configuration Descriptors.
  42  *
  43  *  @{
  44  */
  45
  46 #ifndef __CONFIGDESCRIPTOR_H__
  47 #define __CONFIGDESCRIPTOR_H__
  48
  49         /* Includes: */
  50                 #include <avr/io.h>
  51
  52                 #include "../../../Common/Common.h"
  53                 #include "../LowLevel/HostChapter9.h"
  54                 #include "../HighLevel/StdDescriptors.h"
  55
  56         /* Enable C linkage for C++ Compilers: */
  57                 #if defined(__cplusplus)
  58                         extern "C" {
  59                 #endif
  60
  61         /* Public Interface - May be used in end-application: */
  62                 /* Macros: */
  63                         /** Mask for determining the type of an endpoint from an endpoint descriptor. This should then be compared
  64                          *  with the EP_TYPE_* masks to determine the exact type of the endpoint.
  65                          */
  66                         #define EP_TYPE_MASK                       0x03
  67
  68                         /** Casts a pointer to a descriptor inside the configuration descriptor into a pointer to the given
  69                          *  descriptor type.
  70                          *
  71                          *  Usage Example:
  72                          *  \code
  73                          *  uint8_t* CurrDescriptor = &ConfigDescriptor[0]; // Pointing to the configuration header
  74                          *  USB_Descriptor_Configuration_Header_t* ConfigHeaderPtr = DESCRIPTOR_PCAST(CurrDescriptor,
  75                          *                                                           USB_Descriptor_Configuration_Header_t);
  76                          *
  77                          *  // Can now access elements of the configuration header struct using the -> indirection operator
  78                          *  \endcode
  79                          */
  80                         #define DESCRIPTOR_PCAST(DescriptorPtr, Type) ((Type*)DescriptorPtr)
  81
  82                         /** Casts a pointer to a descriptor inside the configuration descriptor into the given descriptor
  83                          *  type (as an actual struct instance rather than a pointer to a struct).
  84                          *
  85                          *  Usage Example:
  86                          *  \code
  87                          *  uint8_t* CurrDescriptor = &ConfigDescriptor[0]; // Pointing to the configuration header
  88                          *  USB_Descriptor_Configuration_Header_t ConfigHeader = DESCRIPTOR_CAST(CurrDescriptor,
  89                          *                                                       USB_Descriptor_Configuration_Header_t);
  90                          *
  91                          *  // Can now access elements of the configuration header struct using the . operator
  92                          *  \endcode
  93                          */
  94                         #define DESCRIPTOR_CAST(DescriptorPtr, Type)  (*DESCRIPTOR_PCAST(DescriptorPtr, Type))
  95
  96                         /** Returns the descriptor's type, expressed as the 8-bit type value in the header of the descriptor.
  97                          *  This value's meaning depends on the descriptor's placement in the descriptor, but standard type
  98                          *  values can be accessed in the DescriptorTypes_t enum located in USB/HighLevel/StdDescriptors.h.
  99                          */
 100                         #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES) || defined(__DOXYGEN__)
 101                                 #define DESCRIPTOR_TYPE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).Type
 102                         #else
 103                                 #define DESCRIPTOR_TYPE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).bDescriptorType
 104                         #endif
 105
 106                         /** Returns the descriptor's size, expressed as the 8-bit value indicating the number of bytes. */
 107                         #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES) || defined(__DOXYGEN__)
 108                                 #define DESCRIPTOR_SIZE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).Size
 109                         #else
 110                                 #define DESCRIPTOR_SIZE(DescriptorPtr)    DESCRIPTOR_CAST(DescriptorPtr, USB_Descriptor_Header_t).bLength
 111                         #endif
 112
 113                         /** Creates a prototype for or begins a descriptor comparator routine. Descriptor comparator routines are
 114                          *  small search routines which are passed a pointer to the current sub descriptor in the configuration
 115                          *  descriptor, and which analyse the sub descriptor to determine whether or not it matches the routine's
 116                          *  search parameters. Comparator routines provide a powerful way to scan through the config descriptor
 117                          *  for certain descriptors matching unique criteria.
 118                          *
 119                          *  Comparator routines are passed in a single pointer named CurrentDescriptor, and should return a value
 120                          *  of a member of the DSearch_Return_ErrorCodes_t enum.
 121                          */
 122                         #define DESCRIPTOR_COMPARATOR(name)           uint8_t DCOMP_##name (void* const CurrentDescriptor)
 123
 124                         /** Searches for the next descriptor in the given configuration descriptor using a premade comparator
 125                          *  function. The routine updates the position and remaining configuration descriptor bytes values
 126                          *  automatically. If a comparator routine fails a search, the descriptor pointer is retreated back
 127                          *  so that the next descriptor search invocation will start from the descriptor which first caused the
 128                          *  original search to fail. This behaviour allows for one comparator to be used immediately after another
 129                          *  has failed, starting the second search from the descriptor which failed the first.
 130                          *
 131                          *  \param DSize    Pointer to an int storing the remaining bytes in the configuration descriptor
 132                          *  \param DPos     Pointer to the current position in the configuration descriptor
 133                          *  \param DSearch  Name of the comparator search function to use on the configuration descriptor
 134                          *
 135                          *  \return Value of one of the members of the DSearch_Comp_Return_ErrorCodes_t enum
 136                          *
 137                          *  Usage Example:
 138                          *  \code
 139                          *  DESCRIPTOR_COMPARATOR(EndpointSearcher); // Comparator Prototype
 140                          *
 141                          *  DESCRIPTOR_COMPARATOR(EndpointSearcher)
 142                          *  {
 143                          *     if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 144                          *         return Descriptor_Search_Found;
 145                          *     else
 146                          *         return Descriptor_Search_NotFound;
 147                          *  }
 148                          *
 149                          *  //...
 150                          *  // After retrieving configuration descriptor:
 151                          *  if (USB_Host_GetNextDescriptorComp(&BytesRemaining, &ConfigDescriptorData, EndpointSearcher) ==
 152                          *      Descriptor_Search_Comp_Found)
 153                          *  {
 154                          *      // Do something with the endpoint descriptor
 155                          *  }
 156                          *  \endcode
 157                          */
 158                         #define USB_Host_GetNextDescriptorComp(DSize, DPos, DSearch) \
 159                                                                       USB_Host_GetNextDescriptorComp_P(DSize, DPos, DCOMP_##DSearch)
 160                 /* Enums: */
 161                         /** Enum for return values of a descriptor comparator made with DESCRIPTOR_COMPARATOR. */
 162                         enum DSearch_Return_ErrorCodes_t
 163                         {
 164                                 Descriptor_Search_Found                = 0, /**< Current descriptor matches comparator criteria. */
 165                                 Descriptor_Search_Fail                 = 1, /**< No further descriptor could possibly match criteria, fail the search. */
 166                                 Descriptor_Search_NotFound             = 2, /**< Current descriptor does not match comparator criteria. */
 167                         };
 168
 169                         /** Enum for return values of USB_Host_GetNextDescriptorComp() */
 170                         enum DSearch_Comp_Return_ErrorCodes_t
 171                         {
 172                                 Descriptor_Search_Comp_Found           = 0, /**< Configuration descriptor now points to descriptor which matches
 173                                                                              *   search criteria of the given comparator function. */
 174                                 Descriptor_Search_Comp_Fail            = 1, /**< Comparator function returned Descriptor_Search_Fail. */
 175                                 Descriptor_Search_Comp_EndOfDescriptor = 2, /**< End of configuration descriptor reached before match found. */
 176                         };
 177
 178                 /* Function Prototypes: */
 179                         /** Retrieves the configuration descriptor data or size from an attached device via a standard request.
 180                          *
 181                          *  \param ConfigSizePtr  Pointer to a uint16_t for either storing or retrieving the configuration
 182                          *         descriptor size
 183                          *
 184                          *  \param BufferPtr  Pointer to the buffer for storing the configuration descriptor data. If this is
 185                          *                    NULL, the size of the configuration descriptor will be retrieved instead and
 186                          *                    placed in the variable pointed to by ConfigSizePtr. If this is non-NULL, the number
 187                          *                    of bytes indicated by ConfigSizePtr of the configuration descriptor will be loaded
 188                          *                    into the buffer
 189                          */
 190                         uint8_t USB_Host_GetDeviceConfigDescriptor(uint16_t* const ConfigSizePtr, void* BufferPtr)
 191                                                                    ATTR_NON_NULL_PTR_ARG(1);
 192
 193                 /* Inline Functions: */
 194                         /** Skips over the current sub-descriptor inside the configuration descriptor, so that the pointer then
 195                             points to the next sub-descriptor. The bytes remaining value is automatically decremented.
 196                          *
 197                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 198                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 199                          */
 200                         static inline void USB_Host_GetNextDescriptor(uint16_t* const BytesRem,
 201                                                                       uint8_t** const CurrConfigLoc)
 202                                                                                                                   ATTR_NON_NULL_PTR_ARG(1, 2);
 203                         static inline void USB_Host_GetNextDescriptor(uint16_t* const BytesRem,
 204                                                                       uint8_t** const CurrConfigLoc)
 205                         {
 206                                 #if defined(USE_NONSTANDARD_DESCRIPTOR_NAMES)
 207                                 uint16_t CurrDescriptorSize = DESCRIPTOR_CAST(*CurrConfigLoc, USB_Descriptor_Header_t).Size;
 208                                 #else
 209                                 uint16_t CurrDescriptorSize = DESCRIPTOR_CAST(*CurrConfigLoc, USB_Descriptor_Header_t).bLength;
 210                                 #endif
 211
 212                                 *CurrConfigLoc += CurrDescriptorSize;
 213                                 *BytesRem      -= CurrDescriptorSize;
 214                         }
 215
 216                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value.
 217                          *  The bytes remaining value is automatically decremented.
 218                          *
 219                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 220                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 221                          * \param Type  Descriptor type value to search for
 222                          */
 223                         void USB_Host_GetNextDescriptorOfType(uint16_t* const BytesRem,
 224                                                               uint8_t** const CurrConfigLoc,
 225                                                               const uint8_t Type)
 226                                                               ATTR_NON_NULL_PTR_ARG(1, 2);
 227
 228                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value,
 229                          *  which must come before a descriptor of the second given type value. If the BeforeType type
 230                          *  descriptor is reached first, the number of bytes remaining to process is set to zero and the
 231                          *  function exits. The bytes remaining value is automatically decremented.
 232                          *
 233                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 234                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 235                          * \param Type  Descriptor type value to search for
 236                          * \param BeforeType  Descriptor type value which must not be reached before the given Type descriptor
 237                          */
 238                         void USB_Host_GetNextDescriptorOfTypeBefore(uint16_t* const BytesRem,
 239                                                                     uint8_t** const CurrConfigLoc,
 240                                                                     const uint8_t Type,
 241                                                                     const uint8_t BeforeType)
 242                                                                     ATTR_NON_NULL_PTR_ARG(1, 2);
 243
 244                         /** Skips to the next sub-descriptor inside the configuration descriptor of the specified type value,
 245                          *  which must come after a descriptor of the second given type value. The bytes remaining value is
 246                          *  automatically decremented.
 247                          *
 248                          * \param BytesRem  Pointer to the number of bytes remaining of the configuration descriptor
 249                          * \param CurrConfigLoc  Pointer to the current descriptor inside the configuration descriptor
 250                          * \param Type  Descriptor type value to search for
 251                          * \param AfterType  Descriptor type value which must be reached before the given Type descriptor
 252                          */
 253                         void USB_Host_GetNextDescriptorOfTypeAfter(uint16_t* const BytesRem,
 254                                                                    uint8_t** const CurrConfigLoc,
 255                                                                    const uint8_t Type,
 256                                                                    const uint8_t AfterType)
 257                                                                    ATTR_NON_NULL_PTR_ARG(1, 2);
 258
 259         /* Private Interface - For use in library only: */
 260         #if !defined(__DOXYGEN__)
 261                 /* Function Prototypes: */
 262                         uint8_t USB_Host_GetNextDescriptorComp_P(uint16_t* BytesRem, uint8_t** CurrConfigLoc,
 263                                                      uint8_t (* const ComparatorRoutine)(void* const));
 264         #endif
 265
 266         /* Disable C linkage for C++ Compilers: */
 267                 #if defined(__cplusplus)
 268                         }
 269                 #endif
 270
 271 #endif
 272
 273 /** @} */