4.4.5 Power Register, GICR_PWRR

This register controls the power up sequence of the Redistributors. Software must write to this register during the power up sequence.

The GICR_PWRR characteristics are:

Usage constraintsThere are no usage constraints.
ConfigurationsAvailable in all GIC-600 configurations.
AttributesSee 4.4 Redistributor registers for control and physical LPIs summary.

The following figure shows the bit assignments.

Figure 4-21 GICR_PWRR bit assignments
To view this graphic, your browser must support the SVG format. Either install a browser with native support, or install an appropriate plugin such as Adobe SVG Viewer.

The following table shows the bit assignments.

Table 4-26 GICR_PWRR bit assignments

Bits Name Function
[31:24] - Reserved, RAZ.


RDGroup. This read-only field indicates the number of the current Redistributor. Must be packed from 0.



RDGroupOffset. This read-only field indicates the offset of the current core that is connected to the current Redistributor. Must be packed from 0 but does not necessarily map to a single cluster because the AXI4-Stream bus can be subdivided.

[7:4] - Reserved, RAZ.


RDGroupPoweredOff. This read-only bit indicates:

0 = Redistributor is powered up and can be accessed.

1 = It is safe to power down the Redistributor.



RDGroupPowerDown. This read-only bit indicates the intentional power state of the Redistributor:

0 = Intend to power up.

1 = Intend to power down.

The Redistributor has reached its intentional power state when RDGPD = RDGPO.

[1] RDAG

RDApplyGroup. This write-only bit applies the RDPD value to all Redistributors in the group.

If the RDPD value cannot be applied to all cores in the group, then the GIC ignores this request.

[0] RDPD


0 = Redistributor is powered up and can be accessed.

1 = The core permits the Redistributor to be powered down.

Writes to 1 ignored if GICR_WAKER.ProcessorSleep ! = 1.

Writes ignored if RDGPD ! = RDGPO and changing to not match RDGPD.

If all other cores in the Redistributor group have RDPD == 1, then setting this bit to 1 also sets RDGPD = 1.

Non-ConfidentialPDF file icon PDF version100336_0104_00_en
Copyright © 2016–2018 Arm Limited or its affiliates. All rights reserved.