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# MSMON_CSU, MPAM Cache Storage Usage Monitor Register

The MSMON_CSU characteristics are:

## Purpose

MSMON_CSU is a 32-bit read-write register that accesses the CSU monitor selected by MSMON_CFG_MON_SEL.

## Configuration

The power domain of MSMON_CSU is IMPLEMENTATION DEFINED.

This register is present only when MPAMF_IDR.HAS_MSMON == 1 and MPAMF_MSMON_IDR.MSMON_CSU == 1. Otherwise, direct accesses to MSMON_CSU are IMPLEMENTATION DEFINED.

## Attributes

MSMON_CSU is a 32-bit register.

## Field descriptions

The MSMON_CSU bit assignments are:

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
NRDY | VALUE

#### NRDY, bit [31]

Not Ready. Indicates whether the monitor has possibly inaccurate data.

NRDY | Meaning
--- | ---
0b0 | The monitor is not ready and the contents of the VALUE field might be inaccurate or otherwise not represent the actual cache storage usage.
0b1 | The monitor is ready and the VALUE fields is accurate.

#### VALUE, bits [30:0]

Cache storage usage value if NRDY == 0. Invalid if NRDY == 1.

VALUE is the cache storage usage in bytes meeting the criteria set in MSMON_CFG_CSU_FLT and MSMON_CFG_CSU_CTL for the monitor instance selected by MSMON_CFG_MON_SEL.

## Accessing the MSMON_CSU

This register is part of the MPAMF_BASE memory frame. In a system that supports Secure and Non-secure memory maps, the MPAMF_BASE frame must be accessible in both Secure and Non-secure memory address maps.

MSMON_CSU must be accessible from the Non-secure and Secure address maps.

MSMON_CSU must be banked for the Secure and Non-secure address maps. The Secure instance accesses the cache storage usage monitor used for Secure PARTIDs, and the Non-secure instance accesses the cache storage usage monitor used for Non-secure PARTIDs.

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

Component | Frame | Offset | Instance
--- | --- | --- | ---
MPAM.any | MPAMF_BASE_s | 0x0840 | MSMON_CSU_s

Access on this interface is RW.

Component | Frame | Offset | Instance
--- | --- | --- | ---
MPAM.any | MPAMF_BASE_ns | 0x0840 | MSMON_CSU_ns

Access on this interface is RW.

AArch32 Registers | AArch64 Registers | AArch32 Instructions | AArch64 Instructions | Index by Encoding | External Registers | External Registers by Offset | Registers by Functional Group | Proprietary Notice

27/03/2019 21:59; e5e4db499bf9867a4b93324c4dbac985d3da9376

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