GITS_TYPER, ITS Type Register
The GITS_TYPER characteristics are:
Purpose
Specifies the features that an ITS supports.
Configuration
Attributes
GITS_TYPER is a 64-bit register.
Field descriptions
The GITS_TYPER bit assignments are:
| 63 | 62 | 61 | 60 | 59 | 58 | 57 | 56 | 55 | 54 | 53 | 52 | 51 | 50 | 49 | 48 | 47 | 46 | 45 | 44 | 43 | 42 | 41 | 40 | 39 | 38 | 37 | 36 | 35 | 34 | 33 | 32 |
| RES0 | nID | SVPET | VMAPP | VSGI | MPAM | VMOVP | CIL | CIDbits | |||||||||||||||||||||||
| HCC | RES0 | PTA | SEIS | Devbits | ID_bits | ITT_entry_size | IMPLEMENTATION DEFINED | CCT | Virtual | Physical | |||||||||||||||||||||
| 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
Bits [63:44]
Reserved, RES0.
nID, bit [43]
When GICv4.1 is implemented:
When GICv4.1 is implemented:
nID
| nID | Meaning |
|---|---|
| 0b0 |
Individual doorbell interrupt supported. |
| 0b1 |
Individual doorbell interrupt not supported. |
Otherwise:
Otherwise:
Reserved, RES0.
SVPET, bits [42:41]
When GICv4.1 is implemented:
When GICv4.1 is implemented:
SVPET
| SVPET | Meaning |
|---|---|
| 0b00 |
vPE Table is not shared with Redistributors. |
| 0b01 |
vPE Table is shared with the groups of Redistributors indicated by GITS_MPIDR.Aff3. |
| 0b10 |
vPE Table is shared with the groups of Redistributors indicated by GITS_MPIDR fields Aff3 and Aff2. |
| 0b11 |
vPE Table is shared with the groups of Redistributors indicated by GITS_MPIDR fields Aff3, Aff2 and Aff1. |
Otherwise:
Otherwise:
Reserved, RES0.
VMAPP, bit [40]
When GICv4.1 is implemented:
When GICv4.1 is implemented:
VMAPP
| VMAPP | Meaning |
|---|---|
| 0b0 |
GICv4.0 VMAPP command layout. |
| 0b1 |
GICv4.1 VMAPP command layout. |
Otherwise:
Otherwise:
Reserved, RES0.
VSGI, bit [39]
When GICv4.1 is implemented:
When GICv4.1 is implemented:
VSGI
| VSGI | Meaning |
|---|---|
| 0b0 |
Direct injection of SGIs is not supported. |
| 0b1 |
Direct injection of SGIs is supported. |
Otherwise:
Otherwise:
Reserved, RES0.
MPAM, bit [38]
When GIC, >=3.1 is implemented:
When GIC, >=3.1 is implemented:
MPAM
| MPAM | Meaning |
|---|---|
| 0b0 |
MPAM is not supported. |
| 0b1 |
MPAM is supported. |
Otherwise:
Otherwise:
Reserved, RES0.
VMOVP, bit [37]
Indicates the form of the VMOVP command.
| VMOVP | Meaning |
|---|---|
| 0b0 |
When moving a vPE, software must issue a VMOVP on all ITSs that have mappings for that vPE. The ITSList and Sequence Number fields in the VMOVP command must ensure synchronization, otherwise behavior is UNPREDICTABLE. |
| 0b1 |
When moving a vPE, software must only issue a VMOVP on one of the ITSs that has a mapping for that vPE. The ITSList and Sequence Number fields in the VMOVP command are RES0. |
CIL, bit [36]
Collection ID Limit.
| CIL | Meaning |
|---|---|
| 0b0 |
ITS supports 16-bit Collection ID, GITS_TYPER.CIDbits is RES0. |
| 0b1 |
GITS_TYPER.CIDbits indicates supported Collection ID size |
In implementations that do not support Collections in external memory, this bit is RES0 and the number of Collections supported is reported by GITS_TYPER.HCC.
CIDbits, bits [35:32]
Number of Collection ID bits.
- The number of bits of Collection ID minus one.
- When GITS_TYPER.CIL == 0, this field is RES0.
HCC, bits [31:24]
Hardware Collection Count. The number of interrupt collections supported by the ITS without provisioning of external memory.
Collections held in hardware are unmapped at reset.
Bits [23:20]
Reserved, RES0.
PTA, bit [19]
Physical Target Addresses. Indicates the format of the target address:
| PTA | Meaning |
|---|---|
| 0b0 |
The target address corresponds to the PE number specified by GICR_TYPER.Processor_Number. |
| 0b1 |
The target address corresponds to the base physical address of the required Redistributor. |
For more information, see 'RDbase' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).
SEIS, bit [18]
SEI support. Indicates whether the virtual CPU interface supports generation of SEIs:
| SEIS | Meaning |
|---|---|
| 0b0 |
The ITS does not support local generation of SEIs. |
| 0b1 |
The ITS supports local generation of SEIs. |
Devbits, bits [17:13]
The number of DeviceID bits implemented, minus one.
ID_bits, bits [12:8]
The number of EventID bits implemented, minus one.
ITT_entry_size, bits [7:4]
Read-only. Indicates the number of bytes per translation table entry, minus one.
For more information about the ITS command 'MAPD', see MAPD.
IMPLEMENTATION DEFINED, bit [3]
IMPLEMENTATION DEFINED.
CCT, bit [2]
Cumulative Collection Tables.
| CCT | Meaning |
|---|---|
| 0b0 |
The total number of supported collections is determined by the number of collections held in memory only. |
| 0b1 |
The total number of supported collections is determined by number of collections that are held in memory and the number indicated by GITS_TYPER.HCC. |
If GITS_TYPER.HCC == 0, or if memory backed collections are not supported (all GITS_BASER<n>.Type != 100), this bit is RES0.
Virtual, bit [1]
When GICv3 is not implemented:
When GICv3 is not implemented:
Indicates whether the ITS supports virtual LPIs and direct injection of virtual LPIs:
| Virtual | Meaning |
|---|---|
| 0b0 |
The ITS does not support virtual LPIs or direct injection of virtual LPIs. |
| 0b1 |
The ITS supports virtual LPIs and direct injection of virtual LPIs. |
Otherwise:
Otherwise:
Reserved, RES0.
Physical, bit [0]
Indicates whether the ITS supports physical LPIs:
| Physical | Meaning |
|---|---|
| 0b0 |
The ITS does not support physical LPIs. |
| 0b1 |
The ITS supports physical LPIs. |
This field is RES1, indicating that the ITS supports physical LPIs.
Accessing the GITS_TYPER
GITS_TYPER can be accessed through the memory-mapped interfaces:
| Component | Offset | Instance |
|---|---|---|
| GIC ITS control | 0x0008 | GITS_TYPER |
This interface is accessible as follows:
- When GICD_CTLR.DS == 0b0 accesses to this register are RO.
- When IsAccessSecure() accesses to this register are RO.
- When !IsAccessSecure() accesses to this register are RO.