MPAMCFG_MBW_MIN, MPAM Memory Bandwidth Minimum 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. MPAMCFG_MBW_MIN_rt controls the minimum bandwidth for the Root PARTID selected by the Root instance of MPAMCFG_PART_SEL. MPAMCFG_MBW_MIN_rl controls the minimum bandwidth for the Realm PARTID selected by the Realm instance of MPAMCFG_PART_SEL.

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

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_MBW_MIN is IMPLEMENTATION DEFINED.

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

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

Attributes

MPAMCFG_MBW_MIN 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																MIN

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. In an implementation with w implemented bits, the largest fraction of the bandwidth that can be represented is 1- (0.5)^w.

Accessing MPAMCFG_MBW_MIN

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_MBW_MIN_s must only be accessible from the Secure MPAM feature page.
MPAMCFG_MBW_MIN_ns must only be accessible from the Non-secure MPAM feature page.
MPAMCFG_MBW_MIN_rt must only be accessible from the Root MPAM feature page.
MPAMCFG_MBW_MIN_rl must only be accessible from the Realm MPAM feature page.

MPAMCFG_MBW_MIN_s, MPAMCFG_MBW_MIN_ns, MPAMCFG_MBW_MIN_rt, and MPAMCFG_MBW_MIN_rl must be separate registers:

The Secure instance (MPAMCFG_MBW_MIN_s) accesses the memory minimum bandwidth partitioning used for Secure PARTIDs.
The Non-secure instance (MPAMCFG_MBW_MIN_ns) accesses the memory minimum bandwidth partitioning used for Non-secure PARTIDs.
The Root instance (MPAMCFG_MBW_MIN_rt) accesses the memory minimum bandwidth partitioning used for Root PARTIDs.
The Realm instance (MPAMCFG_MBW_MIN_rl) accesses the memory minimum bandwidth partitioning used for Realm PARTIDs.

When RIS is implemented, loads and stores to MPAMCFG_MBW_MIN access the memory minimum bandwidth partitioning configuration settings for the bandwidth 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_MBW_MIN access the memory minimum bandwidth partitioning configuration settings for the PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL.

When PARTID narrowing is implemented, loads and stores to MPAMCFG_MBW_MIN access the memory minimum bandwidth 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_MBW_MIN access the memory minimum bandwidth partitioning configuration settings for the request PARTID selected by MPAMCFG_PART_SEL.PARTID_SEL, and MPAMCFG_PART_SEL.INTERNAL must be 0.

MPAMCFG_MBW_MIN can be accessed through the memory-mapped interfaces:

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_s	0x0200	MPAMCFG_MBW_MIN_s

Accesses on this interface are RW.

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_ns	0x0200	MPAMCFG_MBW_MIN_ns

Accesses on this interface are RW.

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_rt	0x0200	MPAMCFG_MBW_MIN_rt

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

Component	Frame	Offset	Instance
MPAM	MPAMF_BASE_rl	0x0200	MPAMCFG_MBW_MIN_rl

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

26/03/2024 09:49; 67c0ae5282a7629ba0ea0ba7267b43cd4f7939f6