Demos/Host/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_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_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 control interface from the configuration descriptor */
  73         if (USB_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData, NextCDCControlInterface))
  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_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData,
  84                                                    NextInterfaceCDCDataEndpoint))
  85                 {
  86                         /* Check to see if the control interface's notification pipe has been found, if so search for the data interface */
  87                         if (FoundEndpoints & (1 << CDC_NOTIFICATIONPIPE))
  88                         {
  89                                 /* Get the next CDC data interface from the configuration descriptor (CDC class has two CDC interfaces) */
  90                                 if (USB_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData, NextCDCDataInterface))
  91                                 {
  92                                         /* Descriptor not found, error out */
  93                                         return NoCDCInterfaceFound;
  94                                 }
  95                         }
  96                         else
  97                         {
  98                                 /* Get the next CDC control interface from the configuration descriptor (CDC class has two CDC interfaces) */
  99                                 if (USB_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData, NextCDCControlInterface))
 100                                 {
 101                                         /* Descriptor not found, error out */
 102                                         return NoCDCInterfaceFound;
 103                                 }
 104                         }
 105
 106                         /* Fetch the next bulk or interrupt endpoint from the current CDC interface */
 107                         if (USB_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData,
 108                                                                                            NextInterfaceCDCDataEndpoint))
 109                         {
 110                                 /* Descriptor not found, error out */
 111                                 return NoEndpointFound;
 112                         }
 113                 }
 114
 115                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(ConfigDescriptorData, USB_Descriptor_Endpoint_t);
 116
 117                 /* Check if the found endpoint is a interrupt or bulk type descriptor */
 118                 if ((EndpointData->Attributes & EP_TYPE_MASK) == EP_TYPE_INTERRUPT)
 119                 {
 120                         /* If the endpoint is a IN type interrupt endpoint */
 121                         if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 122                         {
 123                                 /* Configure the notification pipe */
 124                                 Pipe_ConfigurePipe(CDC_NOTIFICATIONPIPE, EP_TYPE_INTERRUPT, PIPE_TOKEN_IN,
 125                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 126
 127                                 Pipe_SetInfiniteINRequests();
 128                                 Pipe_SetInterruptPeriod(EndpointData->PollingIntervalMS);
 129
 130                                 /* Set the flag indicating that the notification pipe has been found */
 131                                 FoundEndpoints |= (1 << CDC_NOTIFICATIONPIPE);
 132                         }
 133                 }
 134                 else
 135                 {
 136                         /* Check if the endpoint is a bulk IN or bulk OUT endpoint */
 137                         if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 138                         {
 139                                 /* Configure the data IN pipe */
 140                                 Pipe_ConfigurePipe(CDC_DATAPIPE_IN, EP_TYPE_BULK, PIPE_TOKEN_IN,
 141                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 142
 143                                 Pipe_SetInfiniteINRequests();
 144                                 Pipe_Unfreeze();
 145
 146                                 /* Set the flag indicating that the data IN pipe has been found */
 147                                 FoundEndpoints |= (1 << CDC_DATAPIPE_IN);
 148                         }
 149                         else
 150                         {
 151                                 /* Configure the data OUT pipe */
 152                                 Pipe_ConfigurePipe(CDC_DATAPIPE_OUT, EP_TYPE_BULK, PIPE_TOKEN_OUT,
 153                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 154
 155                                 Pipe_Unfreeze();
 156
 157                                 /* Set the flag indicating that the data OUT pipe has been found */
 158                                 FoundEndpoints |= (1 << CDC_DATAPIPE_OUT);
 159                         }
 160                 }
 161         }
 162
 163         /* Valid data found, return success */
 164         return SuccessfulConfigRead;
 165 }
 166
 167 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 168  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 169  *  descriptor processing if an incompatible descriptor configuration is found.
 170  *
 171  *  This comparator searches for the next Interface descriptor of the correct CDC control Class, Subclass and Protocol values.
 172  *
 173  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 174  */
 175 DESCRIPTOR_COMPARATOR(NextCDCControlInterface)
 176 {
 177         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 178         {
 179                 /* Check the CDC descriptor class, subclass and protocol, break out if correct control interface found */
 180                 if ((DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == CDC_CONTROL_CLASS)    &&
 181                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).SubClass == CDC_CONTROL_SUBCLASS) &&
 182                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Protocol == CDC_CONTROL_PROTOCOL))
 183                 {
 184                         return DESCRIPTOR_SEARCH_Found;
 185                 }
 186         }
 187
 188         return DESCRIPTOR_SEARCH_NotFound;
 189 }
 190
 191 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 192  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 193  *  descriptor processing if an incompatible descriptor configuration is found.
 194  *
 195  *  This comparator searches for the next Interface descriptor of the correct CDC data Class, Subclass and Protocol values.
 196  *
 197  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 198  */
 199 DESCRIPTOR_COMPARATOR(NextCDCDataInterface)
 200 {
 201         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 202         {
 203                 /* Check the CDC descriptor class, subclass and protocol, break out if correct data interface found */
 204                 if ((DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == CDC_DATA_CLASS)    &&
 205                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).SubClass == CDC_DATA_SUBCLASS) &&
 206                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Protocol == CDC_DATA_PROTOCOL))
 207                 {
 208                         return DESCRIPTOR_SEARCH_Found;
 209                 }
 210         }
 211
 212         return DESCRIPTOR_SEARCH_NotFound;
 213 }
 214
 215 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 216  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 217  *  descriptor processing if an incompatible descriptor configuration is found.
 218  *
 219  *  This comparator searches for the next bulk IN or OUT endpoint, or interrupt IN endpoint within the current interface,
 220  *  aborting the search if another interface descriptor is found before the required endpoint (so that it may be compared
 221  *  using a different comparator to determine if it is another CDC class interface).
 222  *
 223  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 224  */
 225 DESCRIPTOR_COMPARATOR(NextInterfaceCDCDataEndpoint)
 226 {
 227         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 228         {
 229                 uint8_t EndpointType = (DESCRIPTOR_CAST(CurrentDescriptor,
 230                                                         USB_Descriptor_Endpoint_t).Attributes & EP_TYPE_MASK);
 231
 232                 if ((EndpointType == EP_TYPE_BULK) || (EndpointType == EP_TYPE_INTERRUPT))
 233                   return DESCRIPTOR_SEARCH_Found;
 234         }
 235         else if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 236         {
 237                 return DESCRIPTOR_SEARCH_Fail;
 238         }
 239
 240         return DESCRIPTOR_SEARCH_NotFound;
 241 }