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MSMON_MBWU

MSMON_MBWU, MPAM Memory Bandwidth Usage Monitor Register

The MSMON_MBWU characteristics are:

Purpose

Accesses the monitor instance selected by MSMON_CFG_MON_SEL.

Configuration

The power domain of MSMON_MBWU is IMPLEMENTATION DEFINED.

This register is present only when (FEAT_MPAMv0p1 is implemented or FEAT_MPAMv1p0 is implemented), MPAMF_IDR.HAS_MSMON == 1, and MPAMF_MSMON_IDR.MSMON_MBWU == 1. Otherwise, direct accesses to MSMON_MBWU are RES0.

If FEAT_MPAM is implemented, the following statements apply:

MSMON_MBWU_s is the Secure memory bandwidth usage monitor instance selected by the Secure instance of MSMON_CFG_MON_SEL.
MSMON_MBWU_ns is the Non-secure memory bandwidth usage monitor instance selected by the Non-secure instance of MSMON_CFG_MON_SEL.
If FEAT_RME is implemented, the following statements also apply:
MSMON_MBWU_rt is the Root memory bandwidth usage monitor instance selected by the Root instance of MSMON_CFG_MON_SEL.
MSMON_MBWU_rl is the Realm memory bandwidth usage monitor instance selected by the Realm instance of MSMON_CFG_MON_SEL.

If any one of these features is implemented:

FEAT_MPAMv0p1
FEAT_MPAMv1p1

then, the following statements apply:

If MPAMF_IDR.HAS_RIS is 1, the monitor instance register accessed is for the resource instance currently selected by MSMON_CFG_MON_SEL.RIS and the monitor instance of that resource instance selected by MSMON_CFG_MON_SEL.MON_SEL.

The power and reset domain of each MSC component is specific to that component.

Attributes

MSMON_MBWU 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
NRDY	VALUE

NRDY, bit [31]

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

NRDY	Meaning
0b0	The monitor instance is ready and the MSMON_MBWU.VALUE field is accurate.
0b1	The monitor instance is not ready and the contents of the MSMON_MBWU.VALUE field might be inaccurate or otherwise not represent the actual memory bandwidth usage.

VALUE, bits [30:0]

Memory bandwidth usage counter value if MSMON_MBWU.NRDY is 0. Invalid if MSMON_MBWU.NRDY is 1.

VALUE is the scaled count of bytes transferred since the monitor was last reset that met the criteria set in MSMON_CFG_MBWU_FLT and MSMON_CFG_MBWU_CTL for the monitor instance selected by MSMON_CFG_MON_SEL.

If MSMON_CFG_MBWU_CTL.SCLEN enables scaling, the count in VALUE is the number of bytes shifted right by MPAMF_MBWUMON_IDR.SCALE bit positions and rounded.

Accessing MSMON_MBWU

If both FEAT_MPAM and FEAT_RME are implemented, the following statements apply:

In a system that supports Secure, Non-secure, Root, and Realm memory maps, there must be MPAM feature pages in all four address maps:
MSMON_MBWU_s must only be accessible from the Secure MPAM feature page.
MSMON_MBWU_ns must only be accessible from the Non-secure MPAM feature page.
MSMON_MBWU_rt must only be accessible from the Root MPAM feature page.
MSMON_MBWU_rl must only be accessible from the Realm MPAM feature page.
MSMON_MBWU_s, MSMON_MBWU_ns, MSMON_MBWU_rt, and MSMON_MBWU_rl must be separate registers:
The Secure instance (MSMON_MBWU_s) accesses the memory bandwidth usage monitor used for Secure PARTIDs.
The Non-secure instance (MSMON_MBWU_ns) accesses the memory bandwidth usage monitor used for Non-secure PARTIDs.
The Root instance (MSMON_MBWU_rt) accesses the memory bandwidth usage monitor used for Root PARTIDs.
The Realm instance (MSMON_MBWU_rl) accesses the memory bandwidth usage monitor used for Realm PARTIDs.

If any one of these features is implemented:

FEAT_MPAMv0p1
FEAT_MPAMv1p1

then, the following statements apply:

When RIS is implemented, reads and writes to MSMON_MBWU access the memory bandwidth usage monitor instance for the resource instance selected by MSMON_CFG_MON_SEL.RIS and the memory bandwidth usage monitor instance selected by MSMON_CFG_MON_SEL.MON_SEL.
When RIS is not implemented, reads and writes to MSMON_MBWU access the memory bandwidth usage monitor instance for the memory bandwidth usage monitor instance selected by MSMON_CFG_MON_SEL.MON_SEL.

Otherwise, the following statements apply:

Reads and writes to MSMON_MBWU access the memory bandwidth usage monitor for the memory bandwidth usage monitor instance selected by MSMON_CFG_MON_SEL.MON_SEL.

MSMON_MBWU can be accessed through the memory-mapped interfaces:

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_s	0x0860	MSMON_MBWU_s

Accesses to this register are RW.

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_ns	0x0860	MSMON_MBWU_ns

Accesses to this register are RW.

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_rt	0x0860	MSMON_MBWU_rt

When FEAT_RME is implemented, accesses to this register are RW.

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_rl	0x0860	MSMON_MBWU_rl

When FEAT_RME is implemented, accesses to this register are RW.

2026-03-12 12:23:09, 2025-09_rel_asl1