C++ IOBufferMemoryDescriptor::prepare方法代码示例

void *pci_alloc_consistent(void *pdev, size_t size, dma_addr_t *dma_handle)
{
	IOBufferMemoryDescriptor    *memDesc;
	IOVirtualAddress            virt_address;
	IOPhysicalAddress           phys_address;

	// construct a memory descriptor for a buffer below the 4Gb line,
	// addressable by 32 bit DMA and page aligned.
	memDesc = IOBufferMemoryDescriptor::inTaskWithOptions(kernel_task,
		kIOMemoryPhysicallyContiguous, size, PAGE_SIZE);
	if (memDesc) {
		IOByteCount		offset = 0;
		IOByteCount		length;

		memDesc->prepare();
		virt_address = (IOVirtualAddress)memDesc->getBytesNoCopy();
		phys_address = memDesc->getPhysicalSegment(offset, &length);

		g_bcm_dma_info->setObject(memDesc);
	} else {
		virt_address = NULL;
		phys_address = NULL;
		IOLog("pci_alloc_consistent:IOBufferMemoryDescriptor::inTaskWithOptions failed\n");
	}

	//IOLog("pci_alloc_consistent paddr(0x%X), size(0x%X)\n", (unsigned int)phys_address, size);
	*dma_handle = phys_address;
	return (void*)virt_address;
}

IOBufferMemoryDescriptor *kXAudioEngine::my_alloc_contiguous(mach_vm_size_t size, void **addr, dword *phys)
{
    if(size<PAGE_SIZE)
		size=PAGE_SIZE;
    
#ifdef DEBUGGING
    size += 2 * PAGE_SIZE;
#endif	
		//void *addr=IOMallocContiguous(size+PAGE_SIZE+PAGE_SIZE,alignment,phys);	
    
    mach_vm_address_t mask = 0x000000007FFFFFFFULL & ~(PAGE_SIZE - 1);
    
    IOBufferMemoryDescriptor *desc =
    IOBufferMemoryDescriptor::inTaskWithPhysicalMask(
													 kernel_task,
													 kIODirectionInOut | kIOMemoryPhysicallyContiguous,
													 size,
													 mask);
    
    if(desc)
    {
		desc->prepare();
		
		IOPhysicalAddress pa = desc->getPhysicalAddress();
		
		if (pa & ~mask)
			debug("kXAudioEngine[%p]::my_alloc_contiguous() - memory misaligned or beyond 2GB limit (%p)\n", this, (void *)pa);
		
		*phys = (dword)pa;
		*addr = desc->getBytesNoCopy();
		
#ifdef DEBUGGING
		memset(addr,0x11,PAGE_SIZE);
		memset((UInt8 *)addr+PAGE_SIZE+size,0x22,PAGE_SIZE);
		
		*((UInt8 *)addr) += PAGE_SIZE;
		*phys += PAGE_SIZE;
#endif
    }
    else
		debug("kXAudioEngine[%p]::my_alloc_contiguous() - allocation failed\n",this);
    
    return desc;
}

IOReturn
IOUSBController::CheckForDisjointDescriptor(IOUSBCommand *command, UInt16 maxPacketSize)
{
    IOMemoryDescriptor			*buf = command->GetBuffer();
    IOBufferMemoryDescriptor	*newBuf = NULL;
    IOByteCount					length = command->GetReqCount();
	IODMACommand				*dmaCommand = command->GetDMACommand();
    IOByteCount					segLength = 0;
    IOByteCount					offset = 0;
    IOReturn					err;
	UInt64						offset64;
	IODMACommand::Segment64		segment64;
	UInt32						numSegments;
	
	// USBTrace_Start( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this );
	
    // Zero length buffers are valid, but they are surely not disjoint, so just return success.  
    //
    if ( length == 0 )
        return kIOReturnSuccess;
	
	if (!dmaCommand)
	{
		USBLog(1, "%s[%p]::CheckForDisjointDescriptor - no dmaCommand", getName(), this);
		USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, kIOReturnBadArgument, 0, 1 );
		return kIOReturnBadArgument;
	}
	
	if (dmaCommand->getMemoryDescriptor() != buf)
	{
		USBLog(1, "%s[%p]::CheckForDisjointDescriptor - mismatched memory descriptor (%p) and dmaCommand memory descriptor (%p)", getName(), this, buf, dmaCommand->getMemoryDescriptor());
		USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, kIOReturnBadArgument, (uintptr_t)buf, (uintptr_t)dmaCommand->getMemoryDescriptor(), 2 );
		return kIOReturnBadArgument;
	}
	
    while (length)
    {
		offset64 = offset;
		numSegments = 1;
		
		err = dmaCommand->gen64IOVMSegments(&offset64, &segment64, &numSegments);
        if (err || (numSegments != 1))
        {
            USBLog(1, "%s[%p]::CheckForDisjointDescriptor - err (%p) trying to generate segments at offset (%qd), length (%d), segLength (%d), total length (%d), buf (%p), numSegments (%d)", getName(), this, (void*)err, offset64, (int)length, (int)segLength, (int)command->GetReqCount(), buf, (int)numSegments);
			USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, offset64, length, segLength, 3 );
			USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, segLength, command->GetReqCount(), numSegments, 4 );
            return kIOReturnBadArgument;
        }

		
		// 3036056 since length might be less than the length of the descriptor, we are OK if the physical
		// segment is longer than we need
        if (segment64.fLength >= length)
            return kIOReturnSuccess;		// this is the last segment, so we are OK
		
		// since length is a 32 bit quantity, then we know from the above statement that if we are here we are 32 bit only
		segLength = (IOByteCount)segment64.fLength;

        // so the segment is less than the rest of the length - we need to check against maxPacketSize
        if (segLength % maxPacketSize)
        {
            // this is the error case. I need to copy the descriptor to a new descriptor and remember that I did it
            USBLog(6, "%s[%p]::CheckForDisjointDescriptor - found a disjoint segment of length (%d) MPS (%d)", getName(), this, (int)segLength, maxPacketSize);
			length = command->GetReqCount();		// we will not return to the while loop, so don't worry about changing the value of length
													// allocate a new descriptor which is the same total length as the old one
			newBuf = IOBufferMemoryDescriptor::withOptions((command->GetDirection() == kUSBIn) ? kIODirectionIn : kIODirectionOut, length);
			if (!newBuf)
			{
				USBLog(1, "%s[%p]::CheckForDisjointDescriptor - could not allocate new buffer", getName(), this);
				USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, kIOReturnNoMemory, 0, 5 );
				return kIOReturnNoMemory;
			}
			USBLog(7, "%s[%p]::CheckForDisjointDescriptor, obtained buffer %p of length %d", getName(), this, newBuf, (int)length);
			
			// first close out (and complete) the original dma command descriptor
			USBLog(7, "%s[%p]::CheckForDisjointDescriptor, clearing memDec (%p) from dmaCommand (%p)", getName(), this, dmaCommand->getMemoryDescriptor(), dmaCommand);
			dmaCommand->clearMemoryDescriptor();
			
			// copy the bytes to the buffer if necessary
			if (command->GetDirection() == kUSBOut)
			{
				USBLog(7, "%s[%p]::CheckForDisjointDescriptor, copying %d bytes from desc %p to buffer %p", getName(), this, (int)length, buf, newBuf->getBytesNoCopy());
				if (buf->readBytes(0, newBuf->getBytesNoCopy(), length) != length)
				{
					USBLog(1, "%s[%p]::CheckForDisjointDescriptor - bad copy on a write", getName(), this);
					USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, 0, 0, 6 );
					newBuf->release();
					return kIOReturnNoMemory;
				}
			}
			err = newBuf->prepare();
			if (err)
			{
				USBLog(1, "%s[%p]::CheckForDisjointDescriptor - err 0x%x in prepare", getName(), this, err);
				USBTrace( kUSBTController, kTPControllerCheckForDisjointDescriptor, (uintptr_t)this, err, 0, 7 );
				newBuf->release();
				return err;
			}
			err = dmaCommand->setMemoryDescriptor(newBuf);
			if (err)
//.........这里部分代码省略.........