Replace blind interface descriptor search in the incomplete AndroidAccessoryHost...

[pub/USBasp.git] / Demos / Host / Incomplete / AndroidAccessoryHost / ConfigDescriptor.c

diff --git a/Demos/Host/Incomplete/AndroidAccessoryHost/ConfigDescriptor.c b/Demos/Host/Incomplete/AndroidAccessoryHost/ConfigDescriptor.c
index 664e065..0dc19e9 100644 (file)
--- a/Demos/Host/Incomplete/AndroidAccessoryHost/ConfigDescriptor.c
+++ b/Demos/Host/Incomplete/AndroidAccessoryHost/ConfigDescriptor.c
@@ -66,18 +66,17 @@ uint8_t ProcessConfigurationDescriptor(void)
                default:
                        return DevControlError;
        }
-
-       /* The Android Accessory Mode specification mandates that the accessory communications endpoints
-          be in the first interface descriptor (interface 0) */
-       USB_GetNextDescriptorOfType(&CurrConfigBytesRem, &CurrConfigLocation, DTYPE_Interface);
-
-       /* Ensure that an interface was found, and the end of the descriptor was not reached */
-       if (!(CurrConfigBytesRem))
-         return NoCompatibleInterfaceFound;
+       
+       /* There should be only one compatible Android Accessory Mode interface in the device, attempt to find it */
+       if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
+                                     DCOMP_NextAndroidAccessoryInterface) != DESCRIPTOR_SEARCH_COMP_Found)
+       {
+               return NoCompatibleInterfaceFound;
+       }
 
        while (!(DataINEndpoint) || !(DataOUTEndpoint))
        {
-               /* Get the next Still Image interface's data endpoint descriptor */
+               /* Get the next Android Accessory Mode interface's data endpoint descriptor */
                if (USB_GetNextDescriptorComp(&CurrConfigBytesRem, &CurrConfigLocation,
                                              DCOMP_NextInterfaceBulkEndpoint) != DESCRIPTOR_SEARCH_COMP_Found)
                {
@@ -111,7 +110,35 @@ uint8_t ProcessConfigurationDescriptor(void)
  *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
  *  descriptor processing if an incompatible descriptor configuration is found.
  *
- *  This comparator searches for the next Endpoint descriptor inside the current interface descriptor, aborting the
+ *  This comparator searches for the next Interface descriptor containing the correct Android Accessory Mode Class, Subclass
+ *  and Protocol values.
+ *
+ *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
+ */
+uint8_t DCOMP_NextAndroidAccessoryInterface(void* const CurrentDescriptor)
+{
+       USB_Descriptor_Header_t* Header = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Header_t);
+
+       if (Header->Type == DTYPE_Interface)
+       {
+               USB_Descriptor_Interface_t* Interface = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Interface_t);
+
+               if ((Interface->Class    == ANDROID_INTERFACE_CLASS)    &&
+                   (Interface->SubClass == ANDROID_INTERFACE_SUBCLASS) &&
+                   (Interface->Protocol == ANDROID_INTERFACE_PROTOCOL))
+               {
+                       return DESCRIPTOR_SEARCH_Found;
+               }
+       }
+
+       return DESCRIPTOR_SEARCH_NotFound;
+}
+
+/** Descriptor comparator function. This comparator function is can be called while processing an attached USB device's
+ *  configuration descriptor, to search for a specific sub descriptor. It can also be used to abort the configuration
+ *  descriptor processing if an incompatible descriptor configuration is found.
+ *
+ *  This comparator searches for the next bulk Endpoint descriptor inside the current interface descriptor, aborting the
  *  search if another interface descriptor is found before the required endpoint.
  *
  *  \return A value from the DSEARCH_Return_ErrorCodes_t enum
@@ -125,6 +152,7 @@ uint8_t DCOMP_NextInterfaceBulkEndpoint(void* const CurrentDescriptor)
                USB_Descriptor_Endpoint_t* Endpoint = DESCRIPTOR_PCAST(CurrentDescriptor, USB_Descriptor_Endpoint_t);
 
                uint8_t EndpointType = (Endpoint->Attributes & EP_TYPE_MASK);
+
                if ((EndpointType == EP_TYPE_BULK) && (!(Pipe_IsEndpointBound(Endpoint->EndpointAddress))))
                  return DESCRIPTOR_SEARCH_Found;
        }