GITS_CWRITER, ITS Write Register

The GITS_CWRITER characteristics are:

Purpose

Specifies the offset from GITS_CBASER where software writes the next ITS command.

Configuration

Bits [63:32] and bits [31:0] are accessible separately.

Attributes

GITS_CWRITER 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
RES0												Offset															RES0				Retry

Bits [63:20]

Reserved, RES0.

Offset, bits [19:5]

Bits [19:5] of the offset from GITS_CBASER. Bits [4:0] of the offset are zero.

The reset behavior of this field is:

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

Bits [4:1]

Reserved, RES0.

Retry, bit [0]

Writing this bit has the following effects:

Retry	Meaning
0b0	No effect on the processing commands by the ITS.
0b1	Restarts the processing of commands by the ITS if it stalled because of a command error. Note If the processing of commands is not stalled because of a command error, writing 1 to this bit has no effect.

When read, this bit is RES0.

For more information, see 'The ITS command interface' in ARM® Generic Interrupt Controller Architecture Specification, GIC architecture version 3.0 and version 4.0 (ARM IHI 0069).

If GITS_CWRITER is written with a value outside of the valid range specified by GITS_CBASER.Physical_Address and GITS_CBASER.Size, behavior is a CONSTRAINED UNPREDICTABLE choice, as follows:

The command queue is considered invalid, and no further commands are processed until GITS_CWRITER is written with a value that is in the valid range.
The value is treated as a valid UNKNOWN value.

An implementation might choose to report a system error in an IMPLEMENTATION DEFINED manner.

Accessing GITS_CWRITER

GITS_CWRITER can be accessed through the memory-mapped interfaces:

Component	Offset	Instance
GIC ITS control	0x0088	GITS_CWRITER

Accesses on this interface are RW.

04/07/2023 11:26; 1b994cb0b8c6d1ae5a9a15edbc8bd6ce3b5c7d68