GICR_IGROUPR0, Interrupt Group Register 0
The GICR_IGROUPR0 characteristics are:
Purpose
Controls whether the corresponding SGI or PPI is in Group 0 or Group 1.
Configuration
This register is available in all GIC configurations. If the GIC implementation supports two Security states, this register is Secure.
A copy of this register is provided for each Redistributor.
Attributes
GICR_IGROUPR0 is a 32-bit register.
Field descriptions
The GICR_IGROUPR0 bit assignments are:
| 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 |
| Redistributor_group_status_bit<x>, bit [x], for x = 0 to 31 | |||||||||||||||||||||||||||||||
Redistributor_group_status_bit<x>, bit [x], for x = 0 to 31
Group status bit. In this register:
- Bits [31:16] are group status bits for PPIs.
- Bits [15:0] are group status bits for SGIs.
| Redistributor_group_status_bit<x> | Meaning |
|---|---|
| 0b0 |
When GICD_CTLR.DS==1, the corresponding interrupt is Group 0. When GICD_CTLR.DS==0, the corresponding interrupt is Secure. |
| 0b1 |
When GICD_CTLR.DS==1, the corresponding interrupt is Group 1. When GICD_CTLR.DS==0, the corresponding interrupt is Non-secure Group 1. |
When GICD_CTLR.DS == 0, the bit that corresponds to the interrupt is concatenated with the equivalent bit in GICR_IGRPMODR0 to form a 2-bit field that defines an interrupt group. The encoding of this field is at GICR_IGRPMODR0.
This field resets to an architecturally UNKNOWN value.
The considerations for the reset value of this register are the same as those for GICD_IGROUPR<n> with n=0.
Accessing the GICR_IGROUPR0
When affinity routing is not enabled for the Security state of an interrupt in GICR_IGROUPR0, the corresponding bit is RES0 and equivalent functionality is provided by GICD_IGROUPR<n> with n=0.
When GICD_CTLR.DS == 0, the register is RAZ/WI to Non-secure accesses.
Bits corresponding to unimplemented interrupts are RAZ/WI.
Implementations must ensure that an interrupt that is pending at the time of the write uses either the old value or the new value and must ensure that the interrupt is neither lost nor handled more than one time. The effect of the change must be visible in finite time.
GICR_IGROUPR0 can be accessed through the memory-mapped interfaces:
| Component | Frame | Offset | Instance |
|---|---|---|---|
| GIC Redistributor | SGI_base | 0x0080 | GICR_IGROUPR0 |
This interface is accessible as follows:
- When GICD_CTLR.DS == 0b0 accesses to this register are RW.
- When IsAccessSecure() accesses to this register are RW.
- When !IsAccessSecure() accesses to this register are RW.