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# MPAMCFG_CMIN, MPAM Cache Minimum Capacity Partition Configuration Register

The MPAMCFG_CMIN characteristics are:

## Purpose

The MPAMCFG_CMIN is a 32-bit read/write register that controls the fraction of the cache capacity that the PARTID selected by MPAMCFG_PART_SEL has priority to allocate.

MPAMCFG_CMIN_s controls the cache minimum capacity for the Secure PARTID selected by the Secure instance of MPAMCFG_PART_SEL. MPAMCFG_CMIN_ns controls the cache minimum capacity for the Non-secure PARTID selected by the Non-secure instance of MPAMCFG_PART_SEL. MPAMCFG_CMIN_rl controls the cache minimum capacity for the Realm PARTID selected by the Realm instance of MPAMCFG_PART_SEL. MPAMCFG_CMIN_rt controls the cache minimum capacity 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_CMIN 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_CMIN == 1. Otherwise, direct accesses to MPAMCFG_CMIN are RES0.

## Attributes

MPAMCFG_CMIN 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 | CMIN

#### Bits [31:16]

Reserved, RES0.

#### CMIN, bits [15:0]

Minimum cache capacity usage in fixed-point fraction format by the partition selected by MPAMCFG_PART_SEL. The fraction represents the portion of the total cache capacity that the PARTID has priority to allocate.

The implemented width of the fixed-point fraction is the same as the width of MPAMCFG_CMAX.CMAX which is given in MPAMF_CCAP_IDR.CMAX_WD. Unimplemented bits within the field are RAZ/WI. The implemented bits of the CMIN field are always the most significant bits of the field.

The fixed-point fraction CMIN 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_CMIN

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_CMIN_s must only be accessible from the Secure MPAM feature page.
- MPAMCFG_CMIN_ns must only be accessible from the Non-secure MPAM feature page.
- MPAMCFG_CMIN_rt must only be accessible from the Root MPAM feature page.
- MPAMCFG_CMIN_rl must only be accessible from the Realm MPAM feature page.

MPAMCFG_CMIN_s, MPAMCFG_CMIN_ns, MPAMCFG_CMIN_rt, and MPAMCFG_CMIN_rl must be separate registers:

- The Secure instance (MPAMCFG_CMIN_s) accesses the cache minimum capacity partitioning used for Secure PARTIDs.
- The Non-secure instance (MPAMCFG_CMIN_ns) accesses the cache minimum capacity partitioning used for Non-secure PARTIDs.
- The Root instance (MPAMCFG_CMIN_rt) accesses the cache minimum capacity partitioning used for Root PARTIDs.
- The Realm instance (MPAMCFG_CMIN_rl) accesses the cache minimum capacity partitioning used for Realm PARTIDs.

When RIS is implemented, loads and stores to MPAMCFG_CMIN access the cache minimum capacity 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_CMIN access the cache minimum capacity partitioning configuration settings for the PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL.

When PARTID narrowing is implemented, loads and stores to MPAMCFG_CMIN access the cache minimum capacity 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_CMIN access the cache minimum capacity partitioning configuration settings for the request PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL, and MPAMCFG_PART_SEL.INTERNAL must be 0.

#### MPAMCFG_CMIN can be accessed through the memory-mapped interfaces:

Component | Frame | Offset | Instance
--- | --- | --- | ---
MPAM | MPAMF_BASE_s | 0x0110 | MPAMCFG_CMIN_s

Accesses on this interface are RW.

Component | Frame | Offset | Instance
--- | --- | --- | ---
MPAM | MPAMF_BASE_ns | 0x0110 | MPAMCFG_CMIN_ns

Accesses on this interface are RW.

Component | Frame | Offset | Instance
--- | --- | --- | ---
MPAM | MPAMF_BASE_rt | 0x0110 | MPAMCFG_CMIN_rt

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

Component | Frame | Offset | Instance
--- | --- | --- | ---
MPAM | MPAMF_BASE_rl | 0x0110 | MPAMCFG_CMIN_rl

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

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26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6

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