Specification Sheet

Datasheet, Volume 2 of 2 339
VC0PREMAP Registers
Bit
Range
Default &
Access
Field Name (ID): Description
63
0h
RW_V
IVT: Software requests IOTLB invalidation by setting this field. Software should also
set the requested invalidation granularity by programming the IIRG field.
Hardware clears the IVT field to indicate the invalidation request is complete.
Hardware also indicates the granularity at which the invalidation operation was
performed through the IAIG field. Software should not submit another invalidation
request through this register while the IVT field is Set, nor update the associated
Invalidate Address register.
Software should not submit IOTLB invalidation requests when there is a context-cache
invalidation request pending at this remapping hardware unit.
Hardware implementations reporting write-buffer flushing requirement (RWBF=1 in
Capability register) should implicitly perform a write buffer flushing before invalidating
the IOTLB.
62
0h
RO
Reserved (RSVD): Reserved.
61:60
0h
RW
IIRG: When requesting hardware to invalidate the IOTLB (by setting the IVT field),
software writes the requested invalidation granularity through this field. The following
are the encodings for the field.
00: Reserved.
01: Global invalidation request.
10: Domain-selective invalidation request. The target domain-id should be specified in
the DID field.
11: Page-selective invalidation request. The target address, mask and invalidation hint
should be specified in the Invalidate Address register, and the domain-id should be
provided in the DID field.
Hardware implementations may process an invalidation request by performing
invalidation at a coarser granularity than requested. Hardware indicates completion of
the invalidation request by clearing the IVT field. At this time, the granularity at which
actual invalidation was performed is reported through the IAIG field
59
0h
RO
Reserved (RSVD): Reserved.
58:57
0h
ROV
IAIG: Hardware reports the granularity at which an invalidation request was
processed through this field when reporting invalidation completion (by clearing the
IVT field).
The following are the encodings for this field.
00: Reserved. This indicates hardware detected an incorrect invalidation request and
ignored the request. Examples of incorrect invalidation requests include detecting an
unsupported address mask value in Invalidate Address register for page-selective
invalidation requests.
01: Global Invalidation performed. This could be in response to a global, domain-
selective, or page-selective invalidation request.
10: Domain-selective invalidation performed using the domain-id specified by software
in the DID field. This could be in response to a domain-selective or a page-selective
invalidation request.
11: Domain-page-selective invalidation performed using the address, mask and hint
specified by software in the Invalidate Address register and domain-id specified in DID
field. This can be in response to a page-selective invalidation request.
56:50
0h
RO
Reserved (RSVD): Reserved.
49
0h
RW
DR: This field is ignored by hardware if the DRD field is reported as clear in the
Capability register. When the DRD field is reported as Set in the Capability register, the
following encodings are supported for this field:
0: Hardware may complete the IOTLB invalidation without draining any translated
DMA read requests.
1: Hardware should drain DMA read requests.
48
0h
RW
DW: This field is ignored by hardware if the DWD field is reported as Clear in the
Capability register. When the DWD field is reported as Set in the Capability register,
the following encodings are supported for this field:
0: Hardware may complete the IOTLB invalidation without draining DMA write
requests.
1: Hardware should drain relevant translated DMA write requests.