usbconfigurationdescriptor.c

本代bootloader通过usb下载代码首先存放在sdram中

/* ----------------------------------------------------------------------------
 *         ATMEL Microcontroller Software Support 
 * ----------------------------------------------------------------------------
 * Copyright (c) 2008, Atmel Corporation
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the disclaimer below.
 *
 * Atmel's name may not be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
 * DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
 * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ----------------------------------------------------------------------------
 */

/*
    Title: USBConfigurationDescriptor implementation

    About: Purpose
        Implementation of the USBConfigurationDescriptor class.
*/

//-----------------------------------------------------------------------------
//         Headers
//-----------------------------------------------------------------------------

#include "USBConfigurationDescriptor.h"

//-----------------------------------------------------------------------------
//         Exported functions
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
/// Returns the total length of a configuration, i.e. including the 
/// descriptors following it.
/// \param configuration Pointer to a USBConfigurationDescriptor instance.
/// \return Total length (in bytes) of the configuration.
//-----------------------------------------------------------------------------
unsigned int USBConfigurationDescriptor_GetTotalLength(
    const USBConfigurationDescriptor *configuration)
{
    return configuration->wTotalLength;
}

//-----------------------------------------------------------------------------
/// Returns the number of interfaces in a configuration.
/// \param configuration Pointer to a USBConfigurationDescriptor instance.
/// \return Number of interfaces in configuration.
//-----------------------------------------------------------------------------
unsigned char USBConfigurationDescriptor_GetNumInterfaces(
    const USBConfigurationDescriptor *configuration)
{
    return configuration->bNumInterfaces;
}

//-----------------------------------------------------------------------------
/// Indicates if the device is self-powered when in a given configuration.
/// \param configuration Pointer to a USBConfigurationDescriptor instance.
/// \return 1 if the device is self-powered when in the given configuration;
///         otherwise 0.
//-----------------------------------------------------------------------------
unsigned char USBConfigurationDescriptor_IsSelfPowered(
    const USBConfigurationDescriptor *configuration)
{
    if ((configuration->bmAttributes & (1 << 6)) != 0) {

        return 1;
    }
    else {

        return 0;
    }
}

//-----------------------------------------------------------------------------
/// Parses the given Configuration descriptor (followed by relevant
/// interface, endpoint and class-specific descriptors) into three arrays.
/// *Each array must have its size equal or greater to the number of
/// descriptors it stores plus one*. A null-value is inserted after the last
/// descriptor of each type to indicate the array end.
///
/// Note that if the pointer to an array is null (0), nothing is stored in
/// it.
/// \param configuration Pointer to the start of the whole Configuration 
///                      descriptor.
/// \param interfaces    Pointer to the Interface descriptor array.
/// \param endpoints     Pointer to the Endpoint descriptor array.
/// \param others        Pointer to the class-specific descriptor array.
//-----------------------------------------------------------------------------
void USBConfigurationDescriptor_Parse(
    const USBConfigurationDescriptor *configuration,
    USBInterfaceDescriptor **interfaces,
    USBEndpointDescriptor **endpoints,
    USBGenericDescriptor **others)
{
    // Get size of configuration to parse
    int size = USBConfigurationDescriptor_GetTotalLength(configuration);
    size -= sizeof(USBConfigurationDescriptor);

    // Start parsing descriptors
    USBGenericDescriptor *descriptor = (USBGenericDescriptor *) configuration;
    while (size > 0) {

        // Get next descriptor
        descriptor = USBGenericDescriptor_GetNextDescriptor(descriptor);
        size -= USBGenericDescriptor_GetLength(descriptor);

        // Store descriptor in correponding array
        if (USBGenericDescriptor_GetType(descriptor)
             == USBGenericDescriptor_INTERFACE) {

            if (interfaces) {
            
                *interfaces = (USBInterfaceDescriptor *) descriptor;
                interfaces++;
            }
        }
        else if (USBGenericDescriptor_GetType(descriptor)
                  == USBGenericDescriptor_ENDPOINT) {

            if (endpoints) {
                
                *endpoints = (USBEndpointDescriptor *) descriptor;
                endpoints++;
            }
        }
        else if (others) {

            *others = descriptor;
            others++;
        }
    }

    // Null-terminate arrays
    if (interfaces) {

        *interfaces = 0;
    }
    if (endpoints) {

        *endpoints = 0;
    }
    if (others) {

        *others = 0;
    }
}