Expand Minimize

MmMapIoSpace routine

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

Syntax


PVOID MmMapIoSpace(
  _In_  PHYSICAL_ADDRESS PhysicalAddress,
  _In_  SIZE_T NumberOfBytes,
  _In_  MEMORY_CACHING_TYPE CacheType
);

Parameters

PhysicalAddress [in]

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

NumberOfBytes [in]

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

CacheType [in]

Specifies a MEMORY_CACHING_TYPE value, which indicates the cache attribute to use to map 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.

Remarks

A driver must call this routine during device start-up if it receives translated resources of type CmResourceTypeMemory in a CM_PARTIAL_RESOURCE_DESCRIPTOR structure. 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 buffers accessible or to make device memory accessible.

For more information about using this routine, see Mapping Bus-Relative Addresses to Virtual Addresses.

Requirements

Version

Available starting with Windows 2000.

Header

Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)

Library

Ntoskrnl.lib

IRQL

<=DISPATCH_LEVEL

See also

MmAllocateContiguousMemory
MmAllocateNonCachedMemory
MmMapLockedPages
MmUnmapIoSpace

 

 

Send comments about this topic to Microsoft

Show:
© 2014 Microsoft