Demos/Host/LowLevel/KeyboardHostWithParser/ConfigDescriptor.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2010  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, distribute, and sell this
  13   software and its documentation for any purpose is hereby granted
  14   without fee, provided that the above copyright notice appear in
  15   all 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  *  USB Device Configuration Descriptor processing routines, to determine the correct pipe configurations
  34  *  needed to communication with an attached USB device. Descriptors are special  computer-readable structures
  35  *  which the host requests upon device enumeration, to determine the device's capabilities and functions.
  36  */
  37
  38 #include "ConfigDescriptor.h"
  39
  40 /** Reads and processes an attached device's descriptors, to determine compatibility and pipe configurations. This
  41  *  routine will read in the entire configuration descriptor, and configure the hosts pipes to correctly communicate
  42  *  with compatible devices.
  43  *
  44  *  This routine searches for a HID interface descriptor containing at least one Interrupt type IN endpoint and HID descriptor.
  45  *
  46  *  \return An error code from the \ref KeyboardHostWithParser_GetConfigDescriptorDataCodes_t enum.
  47  */
  48 uint8_t ProcessConfigurationDescriptor(void)
  49 {
  50         uint8_t  ConfigDescriptorData[512];
  51         void*    CurrConfigLocation = ConfigDescriptorData;
  52         uint16_t CurrConfigBytesRem;
  53
  54         USB_Descriptor_Endpoint_t* DataINEndpoint = NULL;
  55
  56         /* Retrieve the entire configuration descriptor into the allocated buffer */
  57         switch (USB_Host_GetDeviceConfigDescriptor(1, &CurrConfigBytesRem, ConfigDescriptorData, sizeof(ConfigDescriptorData)))
  58         {
  59                 case HOST_GETCONFIG_Successful:
  60                         break;
  61                 case HOST_GETCONFIG_InvalidData:
  62                         return InvalidConfigDataReturned;
  63                 case HOST_GETCONFIG_BuffOverflow:
  64                         return DescriptorTooLarge;
  65                 default:
  66                         return ControlError;
  67         }
  68
  69         /* Get the first HID interface from the configuration descriptor */
  70         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  71                                       DComp_NextKeyboardInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  72         {
  73                 /* Descriptor not found, error out */
  74                 return NoCompatibleInterfaceFound;
  75         }
  76
  77         /* Get the HID descriptor from the configuration descriptor */
  78         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  79                                       DComp_NextHID) != DESCRIPTOR_SEARCH_COMP_Found)
  80         {
  81                 /* Descriptor not found, error out */
  82                 return NoCompatibleInterfaceFound;
  83         }
  84
  85         /* Save the HID report size for later use */
  86         HIDReportSize = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_HID_t)->HIDReportLength;
  87
  88         while (!(DataINEndpoint))
  89         {
  90                 /* Get the next HID interface's data endpoint descriptor */
  91                 if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  92                                               DComp_NextKeyboardInterfaceDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
  93                 {
  94                         /* Get the next HID interface from the configuration descriptor */
  95                         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  96                                                                                   DComp_NextKeyboardInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  97                         {
  98                                 /* Descriptor not found, error out */
  99                                 return NoCompatibleInterfaceFound;
 100                         }
 101
 102                         /* Get the HID descriptor from the configuration descriptor */
 103                         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
 104                                                                                   DComp_NextHID) != DESCRIPTOR_SEARCH_COMP_Found)
 105                         {
 106                                 /* Descriptor not found, error out */
 107                                 return NoCompatibleInterfaceFound;
 108                         }
 109
 110                         /* Save the HID report size for later use */
 111                         HIDReportSize = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_HID_t)->HIDReportLength;
 112
 113                         /* Skip the remainder of the loop as we have not found an endpoint yet */
 114                         continue;
 115                 }
 116
 117                 /* Retrieve the endpoint address from the endpoint descriptor */
 118                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Endpoint_t);
 119
 120                 /* If the endpoint is a IN type endpoint */
 121                 if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 122                   DataINEndpoint = EndpointData;
 123         }
 124
 125         /* Configure the HID data IN pipe */
 126         Pipe_ConfigurePipe(KEYBOARD_DATA_IN_PIPE, EP_TYPE_INTERRUPT, PIPE_TOKEN_IN,
 127                            DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, PIPE_BANK_SINGLE);
 128         Pipe_SetInterruptPeriod(DataINEndpoint->PollingIntervalMS);
 129
 130         /* Valid data found, return success */
 131         return SuccessfulConfigRead;
 132 }
 133
 134 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 135  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 136  *  descriptor processing if an incompatible descriptor configuration is found.
 137  *
 138  *  This comparator searches for the next Interface descriptor of the correct Keyboard HID Class and Protocol values.
 139  *
 140  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 141  */
 142 uint8_t DComp_NextKeyboardInterface(void* CurrentDescriptor)
 143 {
 144         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 145         {
 146                 /* Check the HID descriptor class and protocol, break out if correct class/protocol interface found */
 147                 if ((DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == KEYBOARD_CLASS) &&
 148                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Protocol == KEYBOARD_PROTOCOL))
 149                 {
 150                         return DESCRIPTOR_SEARCH_Found;
 151                 }
 152         }
 153
 154         return DESCRIPTOR_SEARCH_NotFound;
 155 }
 156
 157 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 158  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 159  *  descriptor processing if an incompatible descriptor configuration is found.
 160  *
 161  *  This comparator searches for the next IN Endpoint descriptor inside the current interface descriptor,
 162  *  aborting the search if another interface descriptor is found before the required endpoint.
 163  *
 164  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 165  */
 166 uint8_t DComp_NextKeyboardInterfaceDataEndpoint(void* CurrentDescriptor)
 167 {
 168         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 169         {
 170                 if (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Endpoint_t).EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 171                   return DESCRIPTOR_SEARCH_Found;
 172         }
 173         else if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 174         {
 175                 return DESCRIPTOR_SEARCH_Fail;
 176         }
 177
 178         return DESCRIPTOR_SEARCH_NotFound;
 179 }
 180
 181 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 182  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 183  *  descriptor processing if an incompatible descriptor configuration is found.
 184  *
 185  *  This comparator searches for the next HID descriptor within the current HID interface descriptor.
 186  *
 187  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 188  */
 189 uint8_t DComp_NextHID(void* CurrentDescriptor)
 190 {
 191         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_HID)
 192           return DESCRIPTOR_SEARCH_Found;
 193         else if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 194           return DESCRIPTOR_SEARCH_Fail;
 195         else
 196           return DESCRIPTOR_SEARCH_NotFound;
 197 }