GITS_CWRITER

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GITS_CWRITER, ITS Write Register

Purpose

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

Configuration

Attributes

Field descriptions

Bits [63:20]

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]

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.

Additional information

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:

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