Demos/CDCHost/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 CDC interface descriptor containing bulk data IN and OUT endpoints, and an interrupt event endpoint.
  45  *
  46  *  \return An error code from the CDCHost_GetConfigDescriptorDataCodes_t enum.
  47  */
  48 uint8_t ProcessConfigurationDescriptor(void)
  49 {
  50         uint8_t* ConfigDescriptorData;
  51         uint16_t ConfigDescriptorSize;
  52         uint8_t  FoundEndpoints = 0;
  53
  54         /* Get Configuration Descriptor size from the device */
  55         if (USB_Host_GetDeviceConfigDescriptor(&ConfigDescriptorSize, NULL) != HOST_SENDCONTROL_Successful)
  56           return ControlError;
  57
  58         /* Ensure that the Configuration Descriptor isn't too large */
  59         if (ConfigDescriptorSize > MAX_CONFIG_DESCRIPTOR_SIZE)
  60           return DescriptorTooLarge;
  61
  62         /* Allocate enough memory for the entire config descriptor */
  63         ConfigDescriptorData = alloca(ConfigDescriptorSize);
  64
  65         /* Retrieve the entire configuration descriptor into the allocated buffer */
  66         USB_Host_GetDeviceConfigDescriptor(&ConfigDescriptorSize, ConfigDescriptorData);
  67
  68         /* Validate returned data - ensure first entry is a configuration header descriptor */
  69         if (DESCRIPTOR_TYPE(ConfigDescriptorData) != DTYPE_Configuration)
  70           return InvalidConfigDataReturned;
  71
  72         /* Get the CDC interface from the configuration descriptor */
  73         if (USB_Host_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData, NextCDCInterface))
  74         {
  75                 /* Descriptor not found, error out */
  76                 return NoCDCInterfaceFound;
  77         }
  78
  79         /* Get the IN and OUT data endpoints for the CDC interface */
  80         while (FoundEndpoints != ((1 << CDC_NOTIFICATIONPIPE) | (1 << CDC_DATAPIPE_IN) | (1 << CDC_DATAPIPE_OUT)))
  81         {
  82                 /* Fetch the next bulk or interrupt endpoint from the current CDC interface */
  83                 if (USB_Host_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData,
  84                                                    NextInterfaceCDCDataEndpoint))
  85                 {
  86                         /* Get the next CDC interface from the configuration descriptor (CDC class has two CDC interfaces) */
  87                         if (USB_Host_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData, NextCDCInterface))
  88                         {
  89                                 /* Descriptor not found, error out */
  90                                 return NoCDCInterfaceFound;
  91                         }
  92
  93                         /* Fetch the next bulk or interrupt endpoint from the current CDC interface */
  94                         if (USB_Host_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData,
  95                                                                                            NextInterfaceCDCDataEndpoint))
  96                         {
  97                                 /* Descriptor not found, error out */
  98                                 return NoEndpointFound;
  99                         }
 100                 }
 101
 102                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(ConfigDescriptorData, USB_Descriptor_Endpoint_t);
 103
 104                 /* Check if the found endpoint is a interrupt or bulk type descriptor */
 105                 if ((EndpointData->Attributes & EP_TYPE_MASK) == EP_TYPE_INTERRUPT)
 106                 {
 107                         /* If the endpoint is a IN type interrupt endpoint */
 108                         if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 109                         {
 110                                 /* Configure the notification pipe */
 111                                 Pipe_ConfigurePipe(CDC_NOTIFICATIONPIPE, EP_TYPE_INTERRUPT, PIPE_TOKEN_IN,
 112                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 113
 114                                 Pipe_SetInfiniteINRequests();
 115                                 Pipe_SetInterruptPeriod(EndpointData->PollingIntervalMS);
 116
 117                                 /* Set the flag indicating that the notification pipe has been found */
 118                                 FoundEndpoints |= (1 << CDC_NOTIFICATIONPIPE);
 119                         }
 120                 }
 121                 else
 122                 {
 123                         /* Check if the endpoint is a bulk IN or bulk OUT endpoint */
 124                         if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 125                         {
 126                                 /* Configure the data IN pipe */
 127                                 Pipe_ConfigurePipe(CDC_DATAPIPE_IN, EP_TYPE_BULK, PIPE_TOKEN_IN,
 128                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 129
 130                                 Pipe_SetInfiniteINRequests();
 131                                 Pipe_Unfreeze();
 132
 133                                 /* Set the flag indicating that the data IN pipe has been found */
 134                                 FoundEndpoints |= (1 << CDC_DATAPIPE_IN);
 135                         }
 136                         else
 137                         {
 138                                 /* Configure the data OUT pipe */
 139                                 Pipe_ConfigurePipe(CDC_DATAPIPE_OUT, EP_TYPE_BULK, PIPE_TOKEN_OUT,
 140                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 141
 142                                 Pipe_Unfreeze();
 143
 144                                 /* Set the flag indicating that the data OUT pipe has been found */
 145                                 FoundEndpoints |= (1 << CDC_DATAPIPE_OUT);
 146                         }
 147                 }
 148         }
 149
 150         /* Valid data found, return success */
 151         return SuccessfulConfigRead;
 152 }
 153
 154 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 155  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 156  *  descriptor processing if an incompatible descriptor configuration is found.
 157  *
 158  *  This comparator searches for the next Interface descriptor of the correct CDC Class, Subclass and Protocol values.
 159  *
 160  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 161  */
 162 DESCRIPTOR_COMPARATOR(NextCDCInterface)
 163 {
 164         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 165         {
 166                 /* Check the CDC descriptor class, subclass and protocol, break out if correct control interface found */
 167                 if ((DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == CDC_CONTROL_CLASS)    &&
 168                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).SubClass == CDC_CONTROL_SUBCLASS) &&
 169                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Protocol == CDC_CONTROL_PROTOCOL))
 170                 {
 171                         return Descriptor_Search_Found;
 172                 }
 173
 174                 /* Check the CDC descriptor class, subclass and protocol, break out if correct data interface found */
 175                 if ((DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == CDC_DATA_CLASS)    &&
 176                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).SubClass == CDC_DATA_SUBCLASS) &&
 177                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Protocol == CDC_DATA_PROTOCOL))
 178                 {
 179                         return Descriptor_Search_Found;
 180                 }
 181         }
 182
 183         return Descriptor_Search_NotFound;
 184 }
 185
 186 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 187  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 188  *  descriptor processing if an incompatible descriptor configuration is found.
 189  *
 190  *  This comparator searches for the next bulk IN or OUT endpoint, or interrupt IN endpoint within the current interface,
 191  *  aborting the search if another interface descriptor is found before the required endpoint (so that it may be compared
 192  *  using a different comparator to determine if it is another CDC class interface).
 193  *
 194  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 195  */
 196 DESCRIPTOR_COMPARATOR(NextInterfaceCDCDataEndpoint)
 197 {
 198         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 199         {
 200                 uint8_t EndpointType = (DESCRIPTOR_CAST(CurrentDescriptor,
 201                                                         USB_Descriptor_Endpoint_t).Attributes & EP_TYPE_MASK);
 202
 203                 if ((EndpointType == EP_TYPE_BULK) || (EndpointType == EP_TYPE_INTERRUPT))
 204                   return Descriptor_Search_Found;
 205         }
 206         else if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 207         {
 208                 return Descriptor_Search_Fail;
 209         }
 210
 211         return Descriptor_Search_NotFound;
 212 }