Demos/Host/LowLevel/PrinterHost/ConfigDescriptor.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2012.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   7 */
   8
   9 /*
  10   Copyright 2012  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 #include "ConfigDescriptor.h"
  32
  33 /** Interface number for the bidirectional Printer interface found within the device. */
  34 uint8_t PrinterInterfaceNumber;
  35
  36 /** Interface Alternate Setting number for the bidirectional Printer interface found within the device. */
  37 uint8_t PrinterAltSetting;
  38
  39 /** Reads and processes an attached device's descriptors, to determine compatibility and pipe configurations. This
  40  *  routine will read in the entire configuration descriptor, and configure the hosts pipes to correctly communicate
  41  *  with compatible devices.
  42  *
  43  *  This routine searches for a bidirectional Printer interface descriptor containing bulk IN and OUT data endpoints.
  44  *
  45  *  \return An error code from the \ref PrinterHost_GetConfigDescriptorDataCodes_t enum.
  46  */
  47 uint8_t ProcessConfigurationDescriptor(void)
  48 {
  49         uint8_t  ConfigDescriptorData[512];
  50         void*    CurrConfigLocation = ConfigDescriptorData;
  51         uint16_t CurrConfigBytesRem;
  52
  53         USB_Descriptor_Interface_t* PrinterInterface = NULL;
  54         USB_Descriptor_Endpoint_t*  DataINEndpoint   = NULL;
  55         USB_Descriptor_Endpoint_t*  DataOUTEndpoint  = NULL;
  56
  57         /* Retrieve the entire configuration descriptor into the allocated buffer */
  58         switch (USB_Host_GetDeviceConfigDescriptor(1, &CurrConfigBytesRem, ConfigDescriptorData, sizeof(ConfigDescriptorData)))
  59         {
  60                 case HOST_GETCONFIG_Successful:
  61                         break;
  62                 case HOST_GETCONFIG_InvalidData:
  63                         return InvalidConfigDataReturned;
  64                 case HOST_GETCONFIG_BuffOverflow:
  65                         return DescriptorTooLarge;
  66                 default:
  67                         return ControlError;
  68         }
  69
  70         while (!(DataINEndpoint) || !(DataOUTEndpoint))
  71         {
  72                 /* See if we've found a likely compatible interface, and if there is an endpoint within that interface */
  73                 if (!(PrinterInterface) ||
  74                     USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  75                                               DComp_NextPrinterInterfaceBulkDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
  76                 {
  77                         /* Get the next Printer interface from the configuration descriptor */
  78                         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  79                                                                                   DComp_NextBidirectionalPrinterInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  80                         {
  81                                 /* Descriptor not found, error out */
  82                                 return NoCompatibleInterfaceFound;
  83                         }
  84
  85                         /* Save the interface in case we need to refer back to it later */
  86                         PrinterInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);
  87
  88                         /* Clear any found endpoints */
  89                         DataINEndpoint  = NULL;
  90                         DataOUTEndpoint = NULL;
  91
  92                         /* Skip the remainder of the loop as we have not found an endpoint yet */
  93                         continue;
  94                 }
  95
  96                 /* Retrieve the endpoint address from the endpoint descriptor */
  97                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Endpoint_t);
  98
  99                 /* If the endpoint is a IN type endpoint */
 100                 if ((EndpointData->EndpointAddress & ENDPOINT_DIR_MASK) == ENDPOINT_DIR_IN)
 101                   DataINEndpoint  = EndpointData;
 102                 else
 103                   DataOUTEndpoint = EndpointData;
 104         }
 105
 106         /* Save Printer interface details for later use */
 107         PrinterInterfaceNumber = PrinterInterface->InterfaceNumber;
 108         PrinterAltSetting      = PrinterInterface->AlternateSetting;
 109
 110         /* Configure the Printer data IN pipe */
 111         Pipe_ConfigurePipe(PRINTER_DATA_IN_PIPE, EP_TYPE_BULK, DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, 1);
 112
 113         /* Configure the Printer data OUT pipe */
 114         Pipe_ConfigurePipe(PRINTER_DATA_OUT_PIPE, EP_TYPE_BULK, DataOUTEndpoint->EndpointAddress, DataOUTEndpoint->EndpointSize, 1);
 115
 116         /* Valid data found, return success */
 117         return SuccessfulConfigRead;
 118 }
 119
 120 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 121  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 122  *  descriptor processing if an incompatible descriptor configuration is found.
 123  *
 124  *  This comparator searches for the next Bidirectional Printer Interface descriptor of the current Printer interface,
 125  *  aborting the search if the end of the descriptors is found.
 126  *
 127  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 128  */
 129 uint8_t DComp_NextBidirectionalPrinterInterface(void* CurrentDescriptor)
 130 {
 131         USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
 132
 133         if (Header->Type == DTYPE_Interface)
 134         {
 135                 USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);
 136
 137                 /* Check the descriptor class, subclass and protocol, break out if correct value interface found */
 138                 if ((Interface->Class    == PRNT_CSCP_PrinterClass)    &&
 139                     (Interface->SubClass == PRNT_CSCP_PrinterSubclass) &&
 140                         (Interface->Protocol == PRNT_CSCP_BidirectionalProtocol))
 141                 {
 142                         return DESCRIPTOR_SEARCH_Found;
 143                 }
 144         }
 145
 146         return DESCRIPTOR_SEARCH_NotFound;
 147 }
 148
 149 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 150  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 151  *  descriptor processing if an incompatible descriptor configuration is found.
 152  *
 153  *  This comparator searches for the next Bulk Endpoint descriptor of the current Printer interface, aborting the
 154  *  search if another interface descriptor is found before the next endpoint.
 155  *
 156  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 157  */
 158 uint8_t DComp_NextPrinterInterfaceBulkDataEndpoint(void* CurrentDescriptor)
 159 {
 160         USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
 161
 162         if (Header->Type == DTYPE_Endpoint)
 163         {
 164                 USB_Descriptor_Endpoint_t* Endpoint = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Endpoint_t);
 165
 166                 /* Check the endpoint type, break out if correct BULK type endpoint found */
 167                 if ((Endpoint->Attributes & EP_TYPE_MASK) == EP_TYPE_BULK)
 168                   return DESCRIPTOR_SEARCH_Found;
 169         }
 170         else if (Header->Type == DTYPE_Interface)
 171         {
 172                 return DESCRIPTOR_SEARCH_Fail;
 173         }
 174
 175         return DESCRIPTOR_SEARCH_NotFound;
 176 }
 177