MmMapIoSpace

The MmMapIoSpace routine maps the given physical address range to nonpaged system space.

PVOID 
  MmMapIoSpace(
    IN PHYSICAL_ADDRESS  PhysicalAddress,
    IN ULONG  NumberOfBytes,
    IN MEMORY_CACHING_TYPE  CacheType
    );

Parameters

PhysicalAddress

Specifies the starting physical address of the I/O range to be mapped.

NumberOfBytes

Specifies a value greater than zero, indicating the number of bytes to be mapped.

CacheType

Specifies a MEMORY_CACHING_TYPE value, which indicates the permitted caching behavior when mapping the physical address range.

Return Value

MmMapIoSpace returns the base virtual address that maps the base physical address for the range. If space for mapping the range is insufficient, it returns NULL.

Headers

Declared in wdm.h and ntddk.h. Include wdm.h or ntddk.h.

Comments

A driver must call this routine during device start-up if it receives translated resources of type CmResourceTypeMemory. MmMapIoSpace maps the physical address returned in the resource list to a logical address through which the driver can access device registers.

For example, drivers of PIO devices that allocate long-term I/O buffers can call this routine to make such a buffer accessible or to make device memory accessible.

Callers of MmMapIoSpace must be running at IRQL = PASSIVE_LEVEL.

See Also

HalAllocateCommonBuffer, HalTranslateBusAddress, MmAllocateContiguousMemory, MmAllocateNonCachedMemory, MmMapLockedPages, MmUnmapIoSpace