System Control NI-Tower

The system control NI-Tower is the interconnect in the system control block which connects the AXI interfaces of RSS, MSCP, Debug block to the CMN-Cyprus interconnect.

The System Control NI-Tower needs to be able to operate in a multi-chip environment, and therefore the RSS is required to program the following memory regions based on the value in the CHIP_ID register in the RSS Integration Layer register block.

Following are the requester side interfaces present in the system control NI-Tower:

rss_main_axis: Request from RSS.
scp_axis: Request from SCP.
mcp_axis: Request from MCP.
app_axis: Request from AP.
lcp_axis: Request from LCP targeting LCP/SCP
rss_scp_axis: RSS/SCP access which is filtered out by NIC400 (specifically for region 0x200000000 - 0x23FFFFFFF) and targeted to LCP address space.

Following table shows the connections in the System Control Interconnect:

		rss_main_axis	scp_axis	mcp_axis	app_axis	lcp_axis	rss_scp_axis
rss_scp_axim	Accesses allowed to SCP TCM regions, SCP ATU, SCP RAS and INIT Ctrl registers.	X
rss_mcp_axim	Accesses allowed to MCP TCM regions, MCP ATU, MCP RAS and INIT Ctrl registers.	X
rsm_axim	Shared RAM between RSS, SCP and MCP.	X	X	X
rsm_apbm	ECC Error record register block for Shared RAM between RSS, SCP and MCP.	X	X	X
cmn_apbm	CMN Configuration Space access.	X	X	X
tcu_apbm	TCU configuration path for RSS before the System Control TBU is enabled.	X
lcp_axim	LCP Access						X
app_axim	AP Access	X	X	X
app_scp_axim	SCP Access			X	X
app_mcp_axim	MCP Access				X
lcp_mcp_axim	SCP Access					X

The address map for PSAM and APU configuration can found here: <workspace>/tf-m/platform/ext/target/arm/rss/rdfremont/bl2/ni_tower_sysctrl_lib.c