Demos/Host/LowLevel/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(1, &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(1, &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,
  74                                       DComp_NextCDCControlInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  75         {
  76                 /* Descriptor not found, error out */
  77                 return NoCDCInterfaceFound;
  78         }
  79
  80         /* Get the IN and OUT data endpoints for the CDC interface */
  81         while (FoundEndpoints != ((1 << CDC_NOTIFICATIONPIPE) | (1 << CDC_DATAPIPE_IN) | (1 << CDC_DATAPIPE_OUT)))
  82         {
  83                 /* Fetch the next bulk or interrupt endpoint from the current CDC interface */
  84                 if (USB_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData,
  85                                               DComp_NextInterfaceCDCDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
  86                 {
  87                         /* Check to see if the control interface's notification pipe has been found, if so search for the data interface */
  88                         if (FoundEndpoints & (1 << CDC_NOTIFICATIONPIPE))
  89                         {
  90                                 /* Get the next CDC data interface from the configuration descriptor (CDC class has two CDC interfaces) */
  91                                 if (USB_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData,
  92                                                               DComp_NextCDCDataInterface) != DESCRIPTOR_SEARCH_COMP_Found)
  93                                 {
  94                                         /* Descriptor not found, error out */
  95                                         return NoCDCInterfaceFound;
  96                                 }
  97                         }
  98                         else
  99                         {
 100                                 /* Clear the found endpoints mask, since any already processed endpoints aren't in the CDC interface we need */
 101                                 FoundEndpoints = 0;
 102
 103                                 /* Disable any already configured pipes from the invalid CDC interfaces */
 104                                 Pipe_SelectPipe(CDC_NOTIFICATIONPIPE);
 105                                 Pipe_DisablePipe();
 106                                 Pipe_SelectPipe(CDC_DATAPIPE_IN);
 107                                 Pipe_DisablePipe();
 108                                 Pipe_SelectPipe(CDC_DATAPIPE_OUT);
 109                                 Pipe_DisablePipe();
 110
 111                                 /* Get the next CDC control interface from the configuration descriptor (CDC class has two CDC interfaces) */
 112                                 if (USB_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData,
 113                                                               DComp_NextCDCControlInterface) != DESCRIPTOR_SEARCH_COMP_Found)
 114                                 {
 115                                         /* Descriptor not found, error out */
 116                                         return NoCDCInterfaceFound;
 117                                 }
 118                         }
 119
 120                         /* Fetch the next bulk or interrupt endpoint from the current CDC interface */
 121                         if (USB_GetNextDescriptorComp(&ConfigDescriptorSize, &ConfigDescriptorData,
 122                                                       DComp_NextInterfaceCDCDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
 123                         {
 124                                 /* Descriptor not found, error out */
 125                                 return NoEndpointFound;
 126                         }
 127                 }
 128
 129                 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(ConfigDescriptorData, USB_Descriptor_Endpoint_t);
 130
 131                 /* Check if the found endpoint is a interrupt or bulk type descriptor */
 132                 if ((EndpointData->Attributes & EP_TYPE_MASK) == EP_TYPE_INTERRUPT)
 133                 {
 134                         /* If the endpoint is a IN type interrupt endpoint */
 135                         if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 136                         {
 137                                 /* Configure the notification pipe */
 138                                 Pipe_ConfigurePipe(CDC_NOTIFICATIONPIPE, EP_TYPE_INTERRUPT, PIPE_TOKEN_IN,
 139                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 140
 141                                 Pipe_SetInterruptPeriod(EndpointData->PollingIntervalMS);
 142
 143                                 /* Set the flag indicating that the notification pipe has been found */
 144                                 FoundEndpoints |= (1 << CDC_NOTIFICATIONPIPE);
 145                         }
 146                 }
 147                 else
 148                 {
 149                         /* Check if the endpoint is a bulk IN or bulk OUT endpoint */
 150                         if (EndpointData->EndpointAddress & ENDPOINT_DESCRIPTOR_DIR_IN)
 151                         {
 152                                 /* Configure the data IN pipe */
 153                                 Pipe_ConfigurePipe(CDC_DATAPIPE_IN, EP_TYPE_BULK, PIPE_TOKEN_IN,
 154                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 155
 156                                 /* Set the flag indicating that the data IN pipe has been found */
 157                                 FoundEndpoints |= (1 << CDC_DATAPIPE_IN);
 158                         }
 159                         else
 160                         {
 161                                 /* Configure the data OUT pipe */
 162                                 Pipe_ConfigurePipe(CDC_DATAPIPE_OUT, EP_TYPE_BULK, PIPE_TOKEN_OUT,
 163                                                                    EndpointData->EndpointAddress, EndpointData->EndpointSize, PIPE_BANK_SINGLE);
 164
 165                                 /* Set the flag indicating that the data OUT pipe has been found */
 166                                 FoundEndpoints |= (1 << CDC_DATAPIPE_OUT);
 167                         }
 168                 }
 169         }
 170
 171         /* Valid data found, return success */
 172         return SuccessfulConfigRead;
 173 }
 174
 175 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 176  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 177  *  descriptor processing if an incompatible descriptor configuration is found.
 178  *
 179  *  This comparator searches for the next Interface descriptor of the correct CDC control Class, Subclass and Protocol values.
 180  *
 181  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 182  */
 183 uint8_t DComp_NextCDCControlInterface(void* CurrentDescriptor)
 184 {
 185         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 186         {
 187                 /* Check the CDC descriptor class, subclass and protocol, break out if correct control interface found */
 188                 if ((DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == CDC_CONTROL_CLASS)    &&
 189                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).SubClass == CDC_CONTROL_SUBCLASS) &&
 190                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Protocol == CDC_CONTROL_PROTOCOL))
 191                 {
 192                         return DESCRIPTOR_SEARCH_Found;
 193                 }
 194         }
 195
 196         return DESCRIPTOR_SEARCH_NotFound;
 197 }
 198
 199 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 200  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 201  *  descriptor processing if an incompatible descriptor configuration is found.
 202  *
 203  *  This comparator searches for the next Interface descriptor of the correct CDC data Class, Subclass and Protocol values.
 204  *
 205  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 206  */
 207 uint8_t DComp_NextCDCDataInterface(void* CurrentDescriptor)
 208 {
 209         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 210         {
 211                 /* Check the CDC descriptor class, subclass and protocol, break out if correct data interface found */
 212                 if ((DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Class    == CDC_DATA_CLASS)    &&
 213                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).SubClass == CDC_DATA_SUBCLASS) &&
 214                     (DESCRIPTOR_CAST(CurrentDescriptor, USB_Descriptor_Interface_t).Protocol == CDC_DATA_PROTOCOL))
 215                 {
 216                         return DESCRIPTOR_SEARCH_Found;
 217                 }
 218         }
 219
 220         return DESCRIPTOR_SEARCH_NotFound;
 221 }
 222
 223 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
 224  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
 225  *  descriptor processing if an incompatible descriptor configuration is found.
 226  *
 227  *  This comparator searches for the next bulk IN or OUT endpoint, or interrupt IN endpoint within the current interface,
 228  *  aborting the search if another interface descriptor is found before the required endpoint (so that it may be compared
 229  *  using a different comparator to determine if it is another CDC class interface).
 230  *
 231  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
 232  */
 233 uint8_t DComp_NextInterfaceCDCDataEndpoint(void* CurrentDescriptor)
 234 {
 235         if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Endpoint)
 236         {
 237                 uint8_t EndpointType = (DESCRIPTOR_CAST(CurrentDescriptor,
 238                                                         USB_Descriptor_Endpoint_t).Attributes & EP_TYPE_MASK);
 239
 240                 if ((EndpointType == EP_TYPE_BULK) || (EndpointType == EP_TYPE_INTERRUPT))
 241                   return DESCRIPTOR_SEARCH_Found;
 242         }
 243         else if (DESCRIPTOR_TYPE(CurrentDescriptor) == DTYPE_Interface)
 244         {
 245                 return DESCRIPTOR_SEARCH_Fail;
 246         }
 247
 248         return DESCRIPTOR_SEARCH_NotFound;
 249 }