MPAMCFG_CASSOC, MPAM Cache Maximum Associativity Partition Configuration Register

The MPAMCFG_CASSOC characteristics are:

Purpose

The MPAMCFG_CASSOC is a 32-bit read/write register that controls the maximum fraction of the cache associativity that the PARTID selected by MPAMCFG_PART_SEL is permitted to allocate.

MPAMCFG_CASSOC_s controls the cache maximum associativity for the Secure PARTID selected by the Secure instance of MPAMCFG_PART_SEL. MPAMCFG_CASSOC_ns controls the cache maximum associativity for the Non-secure PARTID selected by the Non-secure instance of MPAMCFG_PART_SEL. MPAMCFG_CASSOC_rl controls the cache maximum associativity for the Realm PARTID selected by the Realm instance of MPAMCFG_PART_SEL. MPAMCFG_CASSOC_rt controls the cache maximum associativity for the Root PARTID selected by the Root instance of MPAMCFG_PART_SEL.

If MPAMF_IDR.HAS_RIS is 1, the control settings accessed are those of the resource instance currently selected by MPAMCFG_PART_SEL.RIS and the PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL.

Configuration

The power domain of MPAMCFG_CASSOC is IMPLEMENTATION DEFINED.

This register is present only when MPAMF_IDR.HAS_CCAP_PART == 1, (FEAT_MPAMv0p1 is implemented or FEAT_MPAMv1p1 is implemented) and MPAMF_CCAP_IDR.HAS_CASSOC == 1. Otherwise, direct accesses to MPAMCFG_CASSOC are RES0.

Attributes

MPAMCFG_CASSOC 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																CASSOC

Bits [31:16]

Reserved, RES0.

CASSOC, bits [15:0]

Maximum cache associativity usage in fixed-point fraction format by the partition selected by MPAMCFG_PART_SEL. The fraction represents the portion of the cache associativity that the PARTID is permitted to allocate. CASSOC controls the fraction of associativity in each associativity grouping of the cache. In a set associative cache, CASSOC applies to the fraction of the ways in each set.

The implemented width of the fixed-point fraction is given in MPAMF_CCAP_IDR.CASSOC_WD. Unimplemented bits within the field are RAZ/WI. The implemented bits of the CASSOC field are always the most significant bits of the field.

The fixed-point fraction CASSOC is less than 1. The implied binary point is between bits 15 and 16. In an implementation with w implemented bits, the largest fraction of the cache that can be represented is 1- (0.5)^w.

Accessing MPAMCFG_CASSOC

This register is within the MPAM feature page memory frames.

In a system that supports Secure, Non-secure, Root, and Realm memory maps, there must be MPAM feature pages in all four address maps:

MPAMCFG_CASSOC_s must only be accessible from the Secure MPAM feature page.
MPAMCFG_CASSOC_ns must only be accessible from the Non-secure MPAM feature page.
MPAMCFG_CASSOC_rt must only be accessible from the Root MPAM feature page.
MPAMCFG_CASSOC_rl must only be accessible from the Realm MPAM feature page.

MPAMCFG_CASSOC_s, MPAMCFG_CASSOC_ns, MPAMCFG_CASSOC_rt, and MPAMCFG_CASSOC_rl must be separate registers:

The Secure instance (MPAMCFG_CASSOC_s) accesses the cache maximum associativity partitioning used for Secure PARTIDs.
The Non-secure instance (MPAMCFG_CASSOC_ns) accesses the cache maximum associativity partitioning used for Non-secure PARTIDs.
The Root instance (MPAMCFG_CASSOC_rt) accesses the cache maximum associativity partitioning used for Root PARTIDs.
The Realm instance (MPAMCFG_CASSOC_rl) accesses the cache maximum associativity partitioning used for Realm PARTIDs.

When RIS is implemented, loads and stores to MPAMCFG_CASSOC access the cache maximum associativity partitioning configuration settings for the cache resource instance selected by MPAMCFG_PART_SEL.RIS and the PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL.

When RIS is not implemented, loads and stores to MPAMCFG_CASSOC access the cache maximum associativity partitioning configuration settings for the PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL.

When PARTID narrowing is implemented, loads and stores to MPAMCFG_CASSOC access the cache maximum associativity partitioning configuration settings for the internal PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL, and MPAMCFG_PART_SEL.INTERNAL must be 1.

When PARTID narrowing is not implemented, loads and stores to MPAMCFG_CASSOC access the cache maximum associativity partitioning configuration settings for the request PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL, and MPAMCFG_PART_SEL.INTERNAL must be 0.

MPAMCFG_CASSOC can be accessed through the memory-mapped interfaces:

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_s	0x0118	MPAMCFG_CASSOC_s

Accesses on this interface are RW.

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_ns	0x0118	MPAMCFG_CASSOC_ns

Accesses on this interface are RW.

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_rt	0x0118	MPAMCFG_CASSOC_rt

When FEAT_RME is implemented, accesses on this interface are RW.

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_rl	0x0118	MPAMCFG_CASSOC_rl

When FEAT_RME is implemented, accesses on this interface are RW.

26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6