Demos/Host/LowLevel/MassStorageHost/ConfigDescriptor.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   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 MSD interface descriptor containing bulk IN and OUT data endpoints.
  45  *
  46  *  \return An error code from the MassStorageHost_GetConfigDescriptorDataCodes_t enum.
  47  */
  48 uint8_t ProcessConfigurationDescriptor(void)
  49 {
  50         uint8_t  ConfigDescriptorData[512];
  51         uint8_t* CurrConfigLocation = ConfigDescriptorData;
  52         uint16_t CurrConfigBytesRem;
  53         uint8_t  FoundEndpoints     = 0;
  54
  55         /* Retrieve the entire configuration descriptor into the allocated buffer */
  56         switch (USB_GetDeviceConfigDescriptor(1, &CurrConfigBytesRem, ConfigDescriptorData, sizeof(ConfigDescriptorData)))
  57         {
  58                 case HOST_GETCONFIG_Successful:
  59                         break;
  60                 case HOST_GETCONFIG_InvalidData:
  61                         return InvalidConfigDataReturned;
  62                 case HOST_GETCONFIG_BuffOverflow:
  63                         return DescriptorTooLarge;
  64                 default:
  65                         return ControlError;
  66         }
  67
  68         /* Get the mass storage interface from the configuration descriptor */
  69         if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  70                                       DComp_NextMassStorageInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  71         {
  72                 /* Descriptor not found, error out */
  73                 return NoInterfaceFound;
  74         }
  75
  76         /* Get the IN and OUT data endpoints for the mass storage interface */
  77         while (FoundEndpoints != ((1 << MASS_STORE_DATA_IN_PIPE) | (1 << MASS_STORE_DATA_OUT_PIPE)))
  78         {
  79                 /* Fetch the next bulk endpoint from the current mass storage interface */
  80                 if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
  81                                               DComp_NextInterfaceBulkDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
  82                 {
  83                         /* Descriptor not found, error out */
  84                         return NoEndpointFound;
  85                 }
  86
  87                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(ConfigDescriptorData, USB_Descriptor_Endpoint_t);
  88
  89                 /* Check if the endpoint is a bulk IN or bulk OUT endpoint, set appropriate globals */
  90                 if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
  91                 {
  92                         /* Configure the data IN pipe */
  93                         Pipe_ConfigurePipe(MASS_STORE_DATA_IN_PIPE, EP_TYPE_BULK, PIPE_TOKEN_IN,
  94                                            EndpointData->EndpointAddress, EndpointData->EndpointSize,
  95                                            PIPE_BANK_DOUBLE);
  96
  97                         /* Set the flag indicating that the data IN pipe has been found */
  98                         FoundEndpoints |= (1 << MASS_STORE_DATA_IN_PIPE);
  99                 }
 100                 else
 101                 {
 102                         /* Configure the data OUT pipe */
 103                         Pipe_ConfigurePipe(MASS_STORE_DATA_OUT_PIPE, EP_TYPE_BULK, PIPE_TOKEN_OUT,
 104                                            EndpointData->EndpointAddress, EndpointData->EndpointSize,
 105                                            PIPE_BANK_DOUBLE);
 106
 107                         /* Set the flag indicating that the data OUT pipe has been found */
 108                         FoundEndpoints |= (1 << MASS_STORE_DATA_OUT_PIPE);
 109                 }
 110         }
 111
 112         /* Valid data found, return success */
 113         return SuccessfulConfigRead;
 114 }
 115
 116 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 117  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 118  *  descriptor processing if an incompatible descriptor configuration is found.
 119  *
 120  *  This comparator searches for the next Interface descriptor of the correct Mass Storage Class, Subclass and Protocol values.
 121  *
 122  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 123  */
 124 uint8_t DComp_NextMassStorageInterface(void* CurrentDescriptor)
 125 {
 126         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 127         {
 128                 /* Check the descriptor class and protocol, break out if correct class/protocol interface found */
 129                 if ((DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == MASS_STORE_CLASS)    &&
 130                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).SubClass == MASS_STORE_SUBCLASS) &&
 131                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Protocol == MASS_STORE_PROTOCOL))
 132                 {
 133                         return DESCRIPTOR_SEARCH_Found;
 134                 }
 135         }
 136
 137         return DESCRIPTOR_SEARCH_NotFound;
 138 }
 139
 140 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 141  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 142  *  descriptor processing if an incompatible descriptor configuration is found.
 143  *
 144  *  This comparator searches for the next Bulk Endpoint descriptor of the correct MSD interface, aborting the search if
 145  *  another interface descriptor is found before the next endpoint.
 146  *
 147  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 148  */
 149 uint8_t DComp_NextInterfaceBulkDataEndpoint(void* CurrentDescriptor)
 150 {
 151         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 152         {
 153                 uint8_t EndpointType = (DESCRIPTOR_CAST(CurrentDescriptor,
 154                                                         USB_Descriptor_Endpoint_t).Attributes & EP_TYPE_MASK);
 155
 156                 /* Check the endpoint type, break out if correct BULK type endpoint found */
 157                 if (EndpointType == EP_TYPE_BULK)
 158                   return DESCRIPTOR_SEARCH_Found;
 159         }
 160         else if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 161         {
 162                 return DESCRIPTOR_SEARCH_Fail;
 163         }
 164
 165         return DESCRIPTOR_SEARCH_NotFound;
 166 }