AM62LX Host Descriptions

Introduction

This chapter provides information on the set of HostIDs permitted in this AM62LX SoC. HostIDs uniquely identify each logically distinct high level software entity. A software entity identification number (HostID) can be assigned to an OS either native or virtualized, or a firmware/native application. The HostID is used to select the set of mailbox channels for which this software entity should use to communicate with the System Firmware.

As an example with an A53 core, then there could be 0, 1, or n number of A53 related hosts. The only limit is the number of available mailbox Channels. Typically though, an A53 core will be assigned one secure host as well as one non secure host, but may be assigned additional hosts for certain usecases. As for other cores, some will only use secure hosts, and others will only use non secure hosts. Since the hosts are tied to mailbox channels, hosts are just a way of sectioning off data for a designated purpose.

System Firmware also checks that the used HostID comes from software running on the correct core (as implied by Host Name in the below table) and with the correct security level (Security Status column).

Additionally, one of the key reasons why HostID is tied in with mailbox channels is because it prevents spoofing. When a message is received by System Firmware, the mailbox channel tied to the HostID in the message is verified against the mailbox channel on which the message was received.

Enumeration of Host IDs

Host ID	Host Name	Security Status	Description
0	TIFS	Secure	Device Management and Security Control
10	A53_0	Secure	Cortex A53 context 0 on Main island
11	A53_1	Secure	Cortex A53 context 1 on Main island
12	A53_2	Non Secure	Cortex A53 context 2 on Main island
13	A53_3	Non Secure	Cortex A53 context 3 on Main island
14	A53_4	Non Secure	Cortex A53 context 4 on Main island