Demos/Host/LowLevel/StillImageHost/ConfigDescriptor.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2011.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2011  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 SI interface descriptor containing bulk IN and OUT data endpoints.
  45  *
  46  *  \return An error code from the \ref StillImageHost_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* StillImageInterface = NULL;
  55         USB_Descriptor_Endpoint_t*  DataINEndpoint      = NULL;
  56         USB_Descriptor_Endpoint_t*  DataOUTEndpoint     = NULL;
  57         USB_Descriptor_Endpoint_t*  EventsEndpoint      = NULL;
  58
  59         /* Retrieve the entire configuration descriptor into the allocated buffer */
  60         switch (USB_Host_GetDeviceConfigDescriptor(1, &CurrConfigBytesRem, ConfigDescriptorData, sizeof(ConfigDescriptorData)))
  61         {
  62                 case HOST_GETCONFIG_Successful:
  63                         break;
  64                 case HOST_GETCONFIG_InvalidData:
  65                         return InvalidConfigDataReturned;
  66                 case HOST_GETCONFIG_BuffOverflow:
  67                         return DescriptorTooLarge;
  68                 default:
  69                         return ControlError;
  70         }
  71
  72         while (!(DataINEndpoint) || !(DataOUTEndpoint))
  73         {
  74                 /* See if we've found a likely compatible interface, and if there is an endpoint within that interface */
  75                 if (!(StillImageInterface) ||
  76                     USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  77                                               DComp_NextStillImageInterfaceDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
  78                 {
  79                         /* Get the next Still Image interface from the configuration descriptor */
  80                         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  81                                                                                   DComp_NextStillImageInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  82                         {
  83                                 /* Descriptor not found, error out */
  84                                 return NoCompatibleInterfaceFound;
  85                         }
  86
  87                         /* Save the interface in case we need to refer back to it later */
  88                         StillImageInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);
  89
  90                         /* Clear any found endpoints */
  91                         DataINEndpoint  = NULL;
  92                         DataOUTEndpoint = NULL;
  93                         EventsEndpoint  = NULL;
  94
  95                         /* Skip the remainder of the loop as we have not found an endpoint yet */
  96                         continue;
  97                 }
  98
  99                 /* Retrieve the endpoint address from the endpoint descriptor */
 100                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Endpoint_t);
 101
 102                 /* If the endpoint is a IN type endpoint */
 103                 if ((EndpointData->EndpointAddress & ENDPOINT_DIR_MASK) == ENDPOINT_DIR_IN)
 104                 {
 105                         /* Check if the found endpoint is a interrupt or bulk type descriptor */
 106                         if ((EndpointData->Attributes & EP_TYPE_MASK) == EP_TYPE_INTERRUPT)
 107                           EventsEndpoint = EndpointData;
 108                         else
 109                           DataINEndpoint = EndpointData;
 110                 }
 111                 else
 112                 {
 113                         DataOUTEndpoint = EndpointData;
 114                 }
 115         }
 116
 117         /* Configure the Still Image data IN pipe */
 118         Pipe_ConfigurePipe(SIMAGE_DATA_IN_PIPE, EP_TYPE_BULK, PIPE_TOKEN_IN,
 119                            DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, PIPE_BANK_SINGLE);
 120
 121         /* Configure the Still Image data OUT pipe */
 122         Pipe_ConfigurePipe(SIMAGE_DATA_OUT_PIPE, EP_TYPE_BULK, PIPE_TOKEN_OUT,
 123                                            DataOUTEndpoint->EndpointAddress, DataOUTEndpoint->EndpointSize, PIPE_BANK_SINGLE);
 124
 125         /* Configure the Still Image events pipe */
 126         Pipe_ConfigurePipe(SIMAGE_EVENTS_PIPE, EP_TYPE_INTERRUPT, PIPE_TOKEN_IN,
 127                                            EventsEndpoint->EndpointAddress, EventsEndpoint->EndpointSize, PIPE_BANK_SINGLE);
 128         Pipe_SetInterruptPeriod(EventsEndpoint->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 Still Image Class, Subclass and Protocol values.
 139  *
 140  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 141  */
 142 uint8_t DComp_NextStillImageInterface(void* CurrentDescriptor)
 143 {
 144         USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
 145
 146         if (Header->Type == DTYPE_Interface)
 147         {
 148                 USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);
 149
 150                 /* Check the descriptor class, subclass and protocol, break out if correct interface found */
 151                 if ((Interface->Class    == SI_CSCP_StillImageClass)    &&
 152                     (Interface->SubClass == SI_CSCP_StillImageSubclass) &&
 153                     (Interface->Protocol == SI_CSCP_BulkOnlyProtocol))
 154                 {
 155                         return DESCRIPTOR_SEARCH_Found;
 156                 }
 157         }
 158
 159         return DESCRIPTOR_SEARCH_NotFound;
 160 }
 161
 162 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 163  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 164  *  descriptor processing if an incompatible descriptor configuration is found.
 165  *
 166  *  This comparator searches for the next Interrupt or Bulk Endpoint descriptor of the current SI interface, aborting the
 167  *  search if another interface descriptor is found before the next endpoint.
 168  *
 169  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 170  */
 171 uint8_t DComp_NextStillImageInterfaceDataEndpoint(void* CurrentDescriptor)
 172 {
 173         USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
 174
 175         if (Header->Type == DTYPE_Endpoint)
 176         {
 177                 USB_Descriptor_Endpoint_t* Endpoint = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Endpoint_t);
 178
 179                 /* Check the endpoint type, break out if correct BULK or INTERRUPT type endpoint found */
 180                 if (((Endpoint->Attributes & EP_TYPE_MASK) == EP_TYPE_BULK) ||
 181                     ((Endpoint->Attributes & EP_TYPE_MASK) == EP_TYPE_INTERRUPT))
 182                 {
 183                         return DESCRIPTOR_SEARCH_Found;
 184                 }
 185         }
 186         else if (Header->Type == DTYPE_Interface)
 187         {
 188                 return DESCRIPTOR_SEARCH_Fail;
 189         }
 190
 191         return DESCRIPTOR_SEARCH_NotFound;
 192 }
 193