Projects/MissileLauncher/ConfigDescriptor.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2013.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2013  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 disclaims 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.
  45  *
  46  *  \return An error code from the GenericHIDHost_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_Descriptor_Endpoint_t*  DataINEndpoint  = NULL;
  56         USB_Descriptor_Endpoint_t*  DataOUTEndpoint = 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) || !(DataOUTEndpoint))
  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_NextHIDInterfaceDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
  77                 {
  78                         /* Not all HID devices have an OUT endpoint - if we've reached the end of the HID descriptor
  79                          * but only found the mandatory IN endpoint, it's safe to continue with the device enumeration */
  80                         if (DataINEndpoint)
  81                           break;
  82
  83                         /* Get the next HID interface from the configuration descriptor */
  84                         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  85                                                                                   DComp_NextHIDInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  86                         {
  87                                 /* Descriptor not found, error out */
  88                                 return NoCompatibleInterfaceFound;
  89                         }
  90
  91                         /* Save the interface in case we need to refer back to it later */
  92                         HIDInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);
  93
  94                         /* Clear any found endpoints */
  95                         DataOUTEndpoint = NULL;
  96
  97                         /* Skip the remainder of the loop as we have not found an endpoint yet */
  98                         continue;
  99                 }
 100
 101                 /* Retrieve the endpoint address from the endpoint descriptor */
 102                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Endpoint_t);
 103
 104                 /* If the endpoint is a IN type endpoint */
 105                 if ((EndpointData->EndpointAddress & ENDPOINT_DIR_MASK) == ENDPOINT_DIR_IN)
 106                   DataINEndpoint  = EndpointData;
 107                 else
 108                   DataOUTEndpoint = EndpointData;
 109         }
 110
 111         /* Configure the HID data IN pipe */
 112         Pipe_ConfigurePipe(HID_DATA_IN_PIPE, EP_TYPE_INTERRUPT, DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, 1);
 113         Pipe_SetInterruptPeriod(DataINEndpoint->PollingIntervalMS);
 114
 115         /* Check if the HID interface contained an optional OUT data endpoint */
 116         if (DataOUTEndpoint)
 117         {
 118                 /* Configure the HID data OUT pipe */
 119                 Pipe_ConfigurePipe(HID_DATA_OUT_PIPE, EP_TYPE_INTERRUPT, DataOUTEndpoint->EndpointAddress, DataOUTEndpoint->EndpointSize, 1);
 120         }
 121
 122         /* Valid data found, return success */
 123         return SuccessfulConfigRead;
 124 }
 125
 126 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 127  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 128  *  descriptor processing if an incompatible descriptor configuration is found.
 129  *
 130  *  This comparator searches for the next Interface descriptor of the correct HID Class value.
 131  *
 132  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 133  */
 134 uint8_t DComp_NextHIDInterface(void* CurrentDescriptor)
 135 {
 136         USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
 137
 138         /* Determine if the current descriptor is an interface descriptor */
 139         if (Header->Type == DTYPE_Interface)
 140         {
 141                 USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);
 142
 143                 /* Check the HID descriptor class and protocol, break out if correct class/protocol interface found */
 144                 if (Interface->Class == HID_CLASS)
 145                 {
 146                         /* Indicate that the descriptor being searched for has been found */
 147                         return DESCRIPTOR_SEARCH_Found;
 148                 }
 149         }
 150
 151         /* Current descriptor does not match what this comparator is looking for */
 152         return DESCRIPTOR_SEARCH_NotFound;
 153 }
 154
 155 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 156  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 157  *  descriptor processing if an incompatible descriptor configuration is found.
 158  *
 159  *  This comparator searches for the next Endpoint descriptor inside the current interface descriptor,
 160  *  aborting the search if another interface descriptor is found before the required endpoint.
 161  *
 162  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 163  */
 164 uint8_t DComp_NextHIDInterfaceDataEndpoint(void* CurrentDescriptor)
 165 {
 166         USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
 167
 168         /* Determine the type of the current descriptor */
 169         if (Header->Type == DTYPE_Endpoint)
 170         {
 171                 /* Indicate that the descriptor being searched for has been found */
 172                 return DESCRIPTOR_SEARCH_Found;
 173         }
 174         else if (Header->Type == DTYPE_Interface)
 175         {
 176                 /* Indicate that the search has failed prematurely and should be aborted */
 177                 return DESCRIPTOR_SEARCH_Fail;
 178         }
 179         else
 180         {
 181                 /* Current descriptor does not match what this comparator is looking for */
 182                 return DESCRIPTOR_SEARCH_NotFound;
 183         }
 184 }
 185