Demos/Host/LowLevel/PrinterHost/ConfigDescriptor.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2010.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6            www.lufa-lib.org
   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 #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_DESCRIPTOR_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, PIPE_TOKEN_IN,
 112                            DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, PIPE_BANK_SINGLE);
 113
 114         /* Configure the Printer data OUT pipe */
 115         Pipe_ConfigurePipe(PRINTER_DATA_OUT_PIPE, EP_TYPE_BULK, PIPE_TOKEN_OUT,
 116                                            DataOUTEndpoint->EndpointAddress, DataOUTEndpoint->EndpointSize, PIPE_BANK_SINGLE);
 117
 118         /* Valid data found, return success */
 119         return SuccessfulConfigRead;
 120 }
 121
 122 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 123  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 124  *  descriptor processing if an incompatible descriptor configuration is found.
 125  *
 126  *  This comparator searches for the next Bidirectional Printer Interface descriptor of the current Printer interface,
 127  *  aborting the search if the end of the descriptors is found.
 128  *
 129  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 130  */
 131 uint8_t DComp_NextBidirectionalPrinterInterface(void* CurrentDescriptor)
 132 {
 133         USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
 134
 135         if (Header->Type == DTYPE_Interface)
 136         {
 137                 USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);
 138
 139                 /* Check the descriptor class, subclass and protocol, break out if correct value interface found */
 140                 if ((Interface->Class    == PRNT_CSCP_PrinterClass)    &&
 141                     (Interface->SubClass == PRNT_CSCP_PrinterSubclass) &&
 142                         (Interface->Protocol == PRNT_CSCP_BidirectionalProtocol))
 143                 {
 144                         return DESCRIPTOR_SEARCH_Found;
 145                 }
 146         }
 147
 148         return DESCRIPTOR_SEARCH_NotFound;
 149 }
 150
 151 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 152  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 153  *  descriptor processing if an incompatible descriptor configuration is found.
 154  *
 155  *  This comparator searches for the next Bulk Endpoint descriptor of the current Printer interface, aborting the
 156  *  search if another interface descriptor is found before the next endpoint.
 157  *
 158  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 159  */
 160 uint8_t DComp_NextPrinterInterfaceBulkDataEndpoint(void* CurrentDescriptor)
 161 {
 162         USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
 163
 164         if (Header->Type == DTYPE_Endpoint)
 165         {
 166                 USB_Descriptor_Endpoint_t* Endpoint = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Endpoint_t);
 167
 168                 /* Check the endpoint type, break out if correct BULK type endpoint found */
 169                 if ((Endpoint->Attributes & EP_TYPE_MASK) == EP_TYPE_BULK)
 170                   return DESCRIPTOR_SEARCH_Found;
 171         }
 172         else if (Header->Type == DTYPE_Interface)
 173         {
 174                 return DESCRIPTOR_SEARCH_Fail;
 175         }
 176
 177         return DESCRIPTOR_SEARCH_NotFound;
 178 }
 179