MPAMCFG_MBW_MIN, MPAM Cache Maximum Capacity Partition Configuration Register

The MPAMCFG_MBW_MIN characteristics are:

Purpose

MPAMCFG_MBW_MIN is a 32-bit read-write register that controls the minimum fraction of memory bandwidth that the PARTID selected by MPAMCFG_PART_SEL is permitted to use. MPAMCFG_MBW_MIN_s controls the minimum bandwidth for the Secure PARTID selected by the Secure instance of MPAMCFG_PART_SEL. MPAMCFG_MBW_MIN_ns controls the minimum bandwidth for the Non-secure PARTID selected by the Non-secure instance of MPAMCFG_PART_SEL.

A PARTID that has used less than MIN is given preferential access to bandwidth.

Configuration

The power domain of MPAMCFG_MBW_MIN is IMPLEMENTATION DEFINED.

This register is present only when MPAMF_IDR.HAS_MBW_PART == 1 and MPAMF_MBW_IDR.HAS_MIN == 1. Otherwise, direct accesses to MPAMCFG_MBW_MIN are RES0.

Attributes

MPAMCFG_MBW_MIN is a 32-bit register.

Field descriptions

The MPAMCFG_MBW_MIN bit assignments are:

Bits [31:16]

Reserved, RES0.

MIN, bits [15:0]

Memory minimum bandwidth allocated to the partition selected by MPAMCFG_PART_SEL. MIN is in fixed-point fraction format. The fraction represents the portion of the total memory bandwidth capacity through the controlled component that the PARTID is permitted to allocate.

The implemented width of the fixed-point fraction is given in MPAMF_MBW_IDR.BWA_WD. Unimplemented bits are RAZ/WI. The implemented bits of the MIN field are always to the left of the field. For example, if BWA_WD = 4, the implemented bits are MPAMCFG_MBW_MIN[15:12] and MPAMCFG_MBW_MIN[11:0] are unimplemented.

The fixed-point fraction MIN is less than 1. The implied binary point is between bits 15 and 16. This representation has as the largest fraction of the cache that can be represented in an implementation with w implemented bits is 1 - 1/w.

Accessing the MPAMCFG_MBW_MIN

This register is within the MPAM feature page memory frames. In a system that supports Secure and Non-secure memory maps, there must be both Secure and Non-secure MPAM feature pages.

MPAMCFG_MBW_MIN_s must be accessible from the Secure MPAM feature page. MPAMCFG_MBW_MIN_ns must be accessible from the Non-secure MPAM feature page.

MPAMCFG_MBW_MIN_s and MPAMCFG_MBW_MIN_ns must be separate registers. The Secure instance (MPAMCFG_MBW_MIN_s) accesses the memory minimum bandwidth partitioning used for Secure PARTIDs, and the Non-secure instance (MPAMCFG_MBW_MIN_ns) accesses the memory minimum bandwidth partitioning used for Non-secure PARTIDs.

MPAMCFG_MBW_MIN can be accessed through the memory-mapped interfaces:

Accesses on this interface are RW.

Accesses on this interface are RW.