getPhysicalSegment

Break a memory descriptor into its physically contiguous segments.

Declaration

#ifdef __LP64__
 virtual addr64_t getPhysicalSegment(
 IOByteCount offset, 
 IOByteCount *length, 
 IOOptionBits options = 0 ) = 0; 
#else /* !__LP64__ */
virtual addr64_t getPhysicalSegment(
 IOByteCount offset, 
 IOByteCount *length, 
 IOOptionBits options ); 
#endif 
/* !__LP64__ */

Parameters

offset: A byte offset into the memory whose physical address to return.
length: If non-zero, getPhysicalSegment will store here the length of the physically contiguous segement at the given offset.

Return Value

A physical address, or zero if the offset is beyond the length of the memory.

Discussion

This method returns the physical address of the byte at the given offset into the memory, and optionally the length of the physically contiguous segment from that offset.

See Also

Miscellaneous

Complete processing of the memory after an I/O transfer finishes.

- createMappingInTask

Maps a IOMemoryDescriptor into a task.

- getDirection

Accessor to get the direction the memory descriptor was created with.

Accessor to get the length of the memory descriptor (over all its ranges).

- getPageCounts

Retrieve the number of resident and/or dirty pages encompassed by an IOMemoryDescriptor.

- getPhysicalAddress

Return the physical address of the first byte in the memory.

Accessor to the retrieve the tag for the memory descriptor.

- initWithOptions

Master initialiser for all variants of memory descriptors. For a more complete description see IOMemoryDescriptor::withOptions.

Maps a IOMemoryDescriptor into the kernel map.

- performOperation

Perform an operation on the memory descriptor's memory.

Prepare the memory for an I/O transfer.

Copy data from the memory descriptor's buffer to the specified buffer.

Establishes an already existing mapping.

- setPurgeable

Control the purgeable status of a memory descriptors memory.

Set the tag for the memory descriptor.

- withAddress

Create an IOMemoryDescriptor to describe one virtual range of the kernel task.

- withAddressRange

Create an IOMemoryDescriptor to describe one virtual range of the specified map.

- withAddressRanges

Create an IOMemoryDescriptor to describe one or more virtual ranges.

- withOptions

Master initialiser for all variants of memory descriptors.

- withPersistentMemoryDescriptor

Copy constructor that generates a new memory descriptor if the backing memory for the same task's virtual address and length has changed.

- withPhysicalAddress

Create an IOMemoryDescriptor to describe one physical range.

Copy data to the memory descriptor's buffer from the specified buffer.