ICC_EOIR0, Interrupt Controller End Of Interrupt Register 0

The ICC_EOIR0 characteristics are:

Purpose

A PE writes to this register to inform the CPU interface that it has completed the processing of the specified Group 0 interrupt.

This register is part of:

Configuration

There is one instance of this register that is used in both Secure and Non-secure states.

AArch32 System register ICC_EOIR0 performs the same function as AArch64 System register ICC_EOIR0_EL1.

Attributes

ICC_EOIR0 is a 32-bit register.

Field descriptions

The ICC_EOIR0 bit assignments are:

313029282726252423222120191817161514131211109876543210
00000000INTID

Bits [31:24]

Reserved, RES0.

INTID, bits [23:0]

The INTID from the corresponding ICC_IAR0 access.

This field has either 16 or 24 bits implemented. The number of implemented bits can be found in ICC_CTLR.IDbits and ICC_MCTLR.IDbits. If only 16 bits are implemented, bits [23:16] of this register are RES0.

If the EOImode bit for the current Exception level and Security state is 0, a write to this register drops the priority for the interrupt, and also deactivates the interrupt.

If the EOImode bit for the current Exception level and Security state is 1, a write to this register only drops the priority for the interrupt. Software must write to ICC_DIR to deactivate the interrupt.

The appropriate EOImode bit varies as follows:

Accessing the ICC_EOIR0

This register can be written using MCR with the following syntax:

MCR <syntax>

This syntax uses the following encoding in the System instruction encoding space:

<syntax> opc1opc2CRncoprocCRm
p15, 0, <Rt>, c12, c8, 1000001110011111000

When HCR.FMO is set to 1, execution of this encoding at Non-secure EL1 results in an access to ICV_EOIR0.

Accessibility

The register is accessible as follows:

Control Accessibility
FMOIMOTGENSEL0EL1EL2EL3
xxx0 - WO n/a WO
xx11 - n/a WOWO
0x01 - WOWOWO
1x01 - ICV_EOIR0 WOWO

This table applies to all instructions that can access this register.

ICC_EOIR0 is only accessible at Non-secure EL1 when HCR.FMO is set to 0.

Note

When HCR.FMO is set to 1, at Non-secure EL1, the instruction encoding used to access ICC_EOIR0 results in an access to ICV_EOIR0.

A write to this register must correspond to the most recent valid read by this PE from an Interrupt Acknowledge Register, and must correspond to the INTID that was read from ICC_IAR0, otherwise the system behavior is UNPREDICTABLE. A valid read is a read that returns a valid INTID that is not a special INTID.

A write of a Special INTID is ignored. See Special INTIDs, for more information.

Traps and enables

For a description of the prioritization of any generated exceptions, see section G1.11.2 (Exception priority order) in the ARM® Architecture Reference Manual, ARMv8, for ARMv8-A architecture profile for exceptions taken to AArch32 state, and section D1.13.2 (Synchronous exception prioritization) for exceptions taken to AArch64 state. Subject to the prioritization rules, the following traps and enables are applicable when accessing this register.

In both Security states, and not dependent on other configuration bits:

When EL2 is implemented and is using AArch64 and SCR_EL3.NS==1 && .E2H==0 :

When EL2 is implemented and is using AArch64 and SCR_EL3.NS==1 && .E2H==1 && HCR_EL2.TGE==0 :

When EL2 is implemented and is using AArch32 and SCR_EL3.NS==1 :

When SCR_EL3.NS==1 :

When EL3 is implemented and is using AArch32 :

When EL3 is implemented and is using AArch32 and SCR_EL3.NS==1 :

When EL3 is implemented and is using AArch64 and SCR_EL3.NS==0 :

When EL3 is implemented and is using AArch64 :

When EL3 is implemented and is using AArch64 and SCR_EL3.NS==1 :




18/04/2017 17:00

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