3 Copyright (C) Dean Camera, 2014.
5 dean [at] fourwalledcubicle [dot] com
10 Copyright 2014 Dean Camera (dean [at] fourwalledcubicle [dot] com)
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.
21 The author disclaims 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
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.
38 #include "ConfigDescriptor.h"
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.
44 * This routine searches for a HID interface descriptor containing at least one Interrupt type IN endpoint and HID descriptor.
46 * \return An error code from the \ref KeyboardHostWithParser_GetConfigDescriptorDataCodes_t enum.
48 uint8_t ProcessConfigurationDescriptor(void)
50 uint8_t ConfigDescriptorData[512];
51 void* CurrConfigLocation = ConfigDescriptorData;
52 uint16_t CurrConfigBytesRem;
54 USB_Descriptor_Interface_t* HIDInterface = NULL;
55 USB_HID_Descriptor_HID_t* HIDDescriptor = NULL;
56 USB_Descriptor_Endpoint_t* DataINEndpoint = NULL;
58 /* Retrieve the entire configuration descriptor into the allocated buffer */
59 switch (USB_Host_GetDeviceConfigDescriptor(1, &CurrConfigBytesRem, ConfigDescriptorData, sizeof(ConfigDescriptorData)))
61 case HOST_GETCONFIG_Successful:
63 case HOST_GETCONFIG_InvalidData:
64 return InvalidConfigDataReturned;
65 case HOST_GETCONFIG_BuffOverflow:
66 return DescriptorTooLarge;
71 while (!(DataINEndpoint))
73 /* See if we've found a likely compatible interface, and if there is an endpoint within that interface */
74 if (!(HIDInterface) ||
75 USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
76 DComp_NextKeyboardInterfaceDataEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
78 /* Get the next HID interface from the configuration descriptor */
79 if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
80 DComp_NextKeyboardInterface) != DESCRIPTOR_SEARCH_COMP_Found)
82 /* Descriptor not found, error out */
83 return NoCompatibleInterfaceFound;
86 /* Save the interface in case we need to refer back to it later */
87 HIDInterface = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Interface_t);
89 /* Get the HID descriptor from the configuration descriptor */
90 if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
91 DComp_NextHID) != DESCRIPTOR_SEARCH_COMP_Found)
93 /* Descriptor not found, error out */
94 return NoCompatibleInterfaceFound;
97 /* Save the HID descriptor for later use */
98 HIDDescriptor = DESCRIPTOR_PCAST(CurrConfigLocation, USB_HID_Descriptor_HID_t);
100 /* Skip the remainder of the loop as we have not found an endpoint yet */
104 /* Retrieve the endpoint address from the endpoint descriptor */
105 USB_Descriptor_Endpoint_t* EndpointData = DESCRIPTOR_PCAST(CurrConfigLocation, USB_Descriptor_Endpoint_t);
107 /* If the endpoint is a IN type endpoint */
108 if ((EndpointData->EndpointAddress & ENDPOINT_DIR_MASK) == ENDPOINT_DIR_IN)
109 DataINEndpoint = EndpointData;
112 /* Configure the HID data IN pipe */
113 Pipe_ConfigurePipe(KEYBOARD_DATA_IN_PIPE, EP_TYPE_INTERRUPT, DataINEndpoint->EndpointAddress, DataINEndpoint->EndpointSize, 1);
114 Pipe_SetInterruptPeriod(DataINEndpoint->PollingIntervalMS);
116 /* Get the HID report size from the HID report descriptor */
117 HIDReportSize = HIDDescriptor->HIDReportLength;
119 /* Valid data found, return success */
120 return SuccessfulConfigRead;
123 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
124 * configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
125 * descriptor processing if an incompatible descriptor configuration is found.
127 * This comparator searches for the next Interface descriptor of the correct Keyboard HID Class and Protocol values.
129 * \return A value from the DSEARCH_Return_ErrorCodes_t enum
131 uint8_t DComp_NextKeyboardInterface(void* CurrentDescriptor)
133 USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
135 if (Header->Type == DTYPE_Interface)
137 USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);
139 /* Check the HID descriptor class, break out if correct class interface found */
140 if (Interface->Class == HID_CSCP_HIDClass)
142 return DESCRIPTOR_SEARCH_Found;
146 return DESCRIPTOR_SEARCH_NotFound;
149 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
150 * configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
151 * descriptor processing if an incompatible descriptor configuration is found.
153 * This comparator searches for the next Endpoint descriptor inside the current interface descriptor, aborting the
154 * search if another interface descriptor is found before the required endpoint.
156 * \return A value from the DSEARCH_Return_ErrorCodes_t enum
158 uint8_t DComp_NextKeyboardInterfaceDataEndpoint(void* CurrentDescriptor)
160 USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
162 if (Header->Type == DTYPE_Endpoint)
163 return DESCRIPTOR_SEARCH_Found;
164 else if (Header->Type == DTYPE_Interface)
165 return DESCRIPTOR_SEARCH_Fail;
167 return DESCRIPTOR_SEARCH_NotFound;
170 /** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
171 * configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
172 * descriptor processing if an incompatible descriptor configuration is found.
174 * This comparator searches for the next HID descriptor within the current HID interface descriptor.
176 * \return A value from the DSEARCH_Return_ErrorCodes_t enum
178 uint8_t DComp_NextHID(void* CurrentDescriptor)
180 USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
182 if (Header->Type == HID_DTYPE_HID)
183 return DESCRIPTOR_SEARCH_Found;
184 else if (Header->Type == DTYPE_Interface)
185 return DESCRIPTOR_SEARCH_Fail;
187 return DESCRIPTOR_SEARCH_NotFound;