GICC_DIR, CPU Interface Deactivate Interrupt Register

The GICC_DIR characteristics are:

Purpose

When interrupt priority drop is separated from interrupt deactivation, a write to this register deactivates the specified interrupt.

Configuration

This register is present only when FEAT_GICv3_LEGACY is implemented. Otherwise, direct accesses to GICC_DIR are RES0.

Attributes

GICC_DIR is a 32-bit register.

Field descriptions

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								INTID

Bits [31:24]

Reserved, RES0.

INTID, bits [23:0]

The INTID of the signaled interrupt.

Note

INTIDs 1020-1023 are reserved and convey additional information such as spurious interrupts.

When affinity routing is not enabled:

Bits [23:13] are RES0.
For SGIs, bits [12:10] identify the CPU interface corresponding to the source PE. For all other interrupts these bits are RES0.

Accessing GICC_DIR

This register is used only when System register access is not enabled. When System register access is enabled:

For AArch32 implementations, ICC_DIR provides equivalent functionality.
For AArch64 implementations, ICC_DIR_EL1 provides equivalent functionality.

Writes to this register have an effect only in the following cases:

When GICD_CTLR.DS == 1, if GICC_CTLR.EOImode == 1.
In GIC implementations that support two Security states:
- If the access is Secure and GICC_CTLR.EOImodeS == 1.
- If the access is Non-secure and GICC_CTLR.EOImodeNS == 1.

The following writes must be ignored:

Writes to this register when the corresponding EOImode field in GICC_CTLR == 0. In systems that support system error generation, an implementation might generate a system error.
Writes to this register when the corresponding EOImode field in GICC_CTLR == 0 and the corresponding interrupt is not active. In systems that support system error generation, an implementation might generate a system error. In implementations using the GIC Stream Protocol Interface, these writes correspond to a Deactivate packet for an interrupt that is not active. For more information, see 'Deactivate (ICC)' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

If the corresponding EOImode field in GICC_CTLR is 1 and this register is written to without a corresponding write to GICC_EOIR or GICC_AEOIR, the interrupt is deactivated but the bit corresponding to it in the active priorities registers remains set.

When affinity routing is enabled for a Security state, it is a programming error to use memory-mapped registers to access the GIC.

GICC_DIR can be accessed through the memory-mapped interfaces:

Component	Offset	Instance
GIC CPU interface	0x1000	GICC_DIR

This interface is accessible as follows:

When GICD_CTLR.DS == 0, accesses to this register are WO.
When an access is Secure, accesses to this register are WO.
When an access is Non-secure, accesses to this register are WO.

26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6