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# GICR_PROPBASER, Redistributor Properties Base Address Register

The GICR_PROPBASER characteristics are:

## Purpose

Specifies the base address of the LPI Configuration table, and the Shareability and Cacheability of accesses to the LPI Configuration table.

## Configuration

A copy of this register is provided for each Redistributor.

An implementation might make this register RO, for example to correspond to an LPI Configuration table in read-only memory.

## Attributes

GICR_PROPBASER is a 64-bit register.

## Field descriptions

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
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
RES0 | OuterCache | RES0 | Physical_Address
Physical_Address | Shareability | InnerCache | RES0 | IDbits

#### Bits [63:59]

Reserved, RES0.

#### OuterCache, bits [58:56]

Indicates the Outer Cacheability attributes of accesses to the LPI Configuration table.

OuterCache | Meaning
--- | ---
0b000 | Memory type defined in InnerCache field. For Normal memory, Outer Cacheability is the same as Inner Cacheability.
0b001 | Normal Outer Non-cacheable.
0b010 | Normal Outer Cacheable Read-allocate, Write-through.
0b011 | Normal Outer Cacheable Read-allocate, Write-back.
0b100 | Normal Outer Cacheable Write-allocate, Write-through.
0b101 | Normal Outer Cacheable Write-allocate, Write-back.
0b110 | Normal Outer Cacheable Read-allocate, Write-allocate, Write-through.
0b111 | Normal Outer Cacheable Read-allocate, Write-allocate, Write-back.

It is IMPLEMENTATION DEFINED whether this field has a fixed value or can be programmed by software. Implementing this field with a fixed value is deprecated.

The reset behavior of this field is:

- On a GIC reset, this field resets to an architecturally UNKNOWN value.

#### Bits [55:52]

Reserved, RES0.

#### Physical_Address, bits [51:12]

Bits [51:12] of the physical address containing the LPI Configuration table.

In implementations supporting fewer than 52 bits of physical address, unimplemented upper bits are RES0.

The reset behavior of this field is:

- On a GIC reset, this field resets to an architecturally UNKNOWN value.

#### Shareability, bits [11:10]

Indicates the Shareability attributes of accesses to the LPI Configuration table.

Shareability | Meaning
--- | ---
0b00 | Non-shareable.
0b01 | Inner Shareable.
0b10 | Outer Shareable.
0b11 | Reserved. Treated as 0b00.

It is IMPLEMENTATION DEFINED whether this field has a fixed value or can be programmed by software. Implementing this field with a fixed value is deprecated.

The reset behavior of this field is:

- On a GIC reset, this field resets to an architecturally UNKNOWN value.

#### InnerCache, bits [9:7]

Indicates the Inner Cacheability attributes of accesses to the LPI Configuration table.

InnerCache | Meaning
--- | ---
0b000 | Device-nGnRnE.
0b001 | Normal Inner Non-cacheable.
0b010 | Normal Inner Cacheable Read-allocate, Write-through.
0b011 | Normal Inner Cacheable Read-allocate, Write-back.
0b100 | Normal Inner Cacheable Write-allocate, Write-through.
0b101 | Normal Inner Cacheable Write-allocate, Write-back.
0b110 | Normal Inner Cacheable Read-allocate, Write-allocate, Write-through.
0b111 | Normal Inner Cacheable Read-allocate, Write-allocate, Write-back.

The reset behavior of this field is:

- On a GIC reset, this field resets to an architecturally UNKNOWN value.

#### Bits [6:5]

Reserved, RES0.

#### IDbits, bits [4:0]

The number of bits of LPI INTID supported, minus one, by the LPI Configuration table starting at Physical_Address.

If the value of this field is larger than the value of GICD_TYPER.IDbits, the GICD_TYPER.IDbits value applies.

If the value of this field is less than 0b1101, indicating that the largest INTID is less than 8192 (the smallest LPI interrupt ID), the GIC will behave as if all physical LPIs are out of range.

The reset behavior of this field is:

- On a GIC reset, this field resets to an architecturally UNKNOWN value.

## Accessing GICR_PROPBASER

It is IMPLEMENTATION DEFINED whether GICR_PROPBASER can be set to different values on different Redistributors. GICR_TYPER.CommonLPIAff identifies the Redistributors that must have GICR_PROPBASER set to the same values whenever GICR_CTLR.EnableLPIs == 1.

Setting different values in different copies of GICR_PROPBASER on Redistributors that are required to use a common LPI Configuration table when GICR_CTLR.EnableLPIs == 1 leads to UNPREDICTABLE behavior.

Other restrictions apply when a Redistributor caches information from GICR_PROPBASER. For more information, see 'LPI Configuration tables' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

#### GICR_PROPBASER can be accessed through the memory-mapped interfaces:

Component | Frame | Offset | Instance
--- | --- | --- | ---
GIC Redistributor | RD_base | 0x0070 | GICR_PROPBASER

Accesses on this interface are RW.

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26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

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