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_Interface_t* HIDInterface   = NULL;
  55         USB_HID_Descriptor_HID_t*   HIDDescriptor  = NULL;
  56         USB_Descriptor_Endpoint_t*  DataINEndpoint = NULL;
  57
  58         /* Retrieve the entire configuration descriptor into the allocated buffer */
  59         switch (USB_Host_GetDeviceConfigDescriptor(1, &CurrConfigBytesRem, ConfigDescriptorData, sizeof(ConfigDescriptorData)))
  60         {
  61                 case HOST_GETCONFIG_Successful:
  62                         break;
  63                 case HOST_GETCONFIG_InvalidData:
  64                         return InvalidConfigDataReturned;
  65                 case HOST_GETCONFIG_BuffOverflow:
  66                         return DescriptorTooLarge;
  67                 default:
  68                         return ControlError;
  69         }
  70
  71         while (!(DataINEndpoint))
  72         {
  73                 /* See if we've found a likely compatible interface, and if there is an endpoint within that interface */
  74                 if (!(HIDInterface) ||
  75                     USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  76                                               DComp_NextKeyboardInterfaceDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
  77                 {
  78                         /* Get the next HID interface from the configuration descriptor */
  79                         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  80                                                                                   DComp_NextKeyboardInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  81                         {
  82                                 /* Descriptor not found, error out */
  83                                 return NoCompatibleInterfaceFound;
  84                         }
  85
  86                         /* Save the interface in case we need to refer back to it later */
  87                         HIDInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);
  88
  89                         /* Get the HID descriptor from the configuration descriptor */
  90                         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  91                                                                                   DComp_NextHID) != DESCRIPTOR_SEARCH_COMP_Found)
  92                         {
  93                                 /* Descriptor not found, error out */
  94                                 return NoCompatibleInterfaceFound;
  95                         }
  96
  97                         /* Save the HID descriptor for later use */
  98                         HIDDescriptor = DESCRIPTOR_PCAST(CurrConfigLocation, USB_HID_Descriptor_HID_t);
  99
 100                         /* Skip the remainder of the loop as we have not found an endpoint yet */
 101                         continue;
 102                 }
 103
 104                 /* Retrieve the endpoint address from the endpoint descriptor */
 105                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Endpoint_t);
 106
 107                 /* If the endpoint is a IN type endpoint */
 108                 if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 109                   DataINEndpoint = EndpointData;
 110         }
 111
 112         /* Configure the HID data IN pipe */
 113         Pipe_ConfigurePipe(KEYBOARD_DATA_IN_PIPE, EP_TYPE_INTERRUPT, PIPE_TOKEN_IN,
 114                            DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, PIPE_BANK_SINGLE);
 115         Pipe_SetInterruptPeriod(DataINEndpoint->PollingIntervalMS);
 116
 117         /* Get the HID report size from the HID report descriptor */
 118         HIDReportSize = HIDDescriptor->HIDReportLength;
 119
 120         /* Valid data found, return success */
 121         return SuccessfulConfigRead;
 122 }
 123
 124 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 125  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 126  *  descriptor processing if an incompatible descriptor configuration is found.
 127  *
 128  *  This comparator searches for the next Interface descriptor of the correct Keyboard HID Class and Protocol values.
 129  *
 130  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 131  */
 132 uint8_t DComp_NextKeyboardInterface(void* CurrentDescriptor)
 133 {
 134         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 135         {
 136                 /* Check the HID descriptor class, break out if correct class interface found */
 137                 if (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == HID_CSCP_HIDClass)
 138                 {
 139                         return DESCRIPTOR_SEARCH_Found;
 140                 }
 141         }
 142
 143         return DESCRIPTOR_SEARCH_NotFound;
 144 }
 145
 146 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 147  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 148  *  descriptor processing if an incompatible descriptor configuration is found.
 149  *
 150  *  This comparator searches for the next IN Endpoint descriptor inside the current interface descriptor,
 151  *  aborting the search if another interface descriptor is found before the required endpoint.
 152  *
 153  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 154  */
 155 uint8_t DComp_NextKeyboardInterfaceDataEndpoint(void* CurrentDescriptor)
 156 {
 157         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 158         {
 159                 if (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Endpoint_t).EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 160                   return DESCRIPTOR_SEARCH_Found;
 161         }
 162         else if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 163         {
 164                 return DESCRIPTOR_SEARCH_Fail;
 165         }
 166
 167         return DESCRIPTOR_SEARCH_NotFound;
 168 }
 169
 170 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 171  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 172  *  descriptor processing if an incompatible descriptor configuration is found.
 173  *
 174  *  This comparator searches for the next HID descriptor within the current HID interface descriptor.
 175  *
 176  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 177  */
 178 uint8_t DComp_NextHID(void* CurrentDescriptor)
 179 {
 180         if (DESCRIPTOR_TYPE(CurrentDescriptor) == HID_DTYPE_HID)
 181           return DESCRIPTOR_SEARCH_Found;
 182         else if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 183           return DESCRIPTOR_SEARCH_Fail;
 184         else
 185           return DESCRIPTOR_SEARCH_NotFound;
 186 }
 187