drbg_axis_edn_adapter

Fan a 32-bit AXI-Stream entropy source out to native EDN client ports.

Entropy passes through these pipeline stages in order:

axis (32b) into a 4-entry prim_fifo_sync staging FIFO.
prim_arbiter_ppc round-robin arbitration across N requesters.
A per-endpoint 1-deep holding FIFO.
edn_ack_sm driving edn_ack / edn_bus.

edn_fips is forwarded from the AXI-Stream tuser sideband through both FIFO stages so a FIPS-aware client such as OTBN RND sees correct provenance. Upstream producers drive tuser:

The DRBG native-EDN-to-AXIS adapter forwards edn_fips from u_edn.
External streams should drive it from the producer's FIPS policy, commonly tied low when the source is not NIST SP 800-90A approved.

clear_i synchronously flushes staged entropy and every endpoint. endpoint_cancel_i synchronously cancels only the corresponding endpoint and does not disturb another client's in-flight response. It must assert before the client's reset asserts and hold until that reset deasserts.

Parameters

Table 1. Parameters
Name	Type	Default	Description
`NUM_ENDPOINTS`	`int unsigned`	`4`	Number of native EDN clients (e.g. AES, KMAC, OTBN RND/URND).

Ports

Table 2. Ports
Name	Direction	Type	Description
`clk_i`	input	`logic`	System clock.
`rst_ni`	input	`logic`	Async reset, active-low.
`endpoint_cancel_i`	input	`logic [NUM_ENDPOINTS-1:0]`	Per-client synchronous cancel. Must assert before its reset and hold until the reset deasserts; does not disturb other clients.
`clear_i`	input	`logic`	Synchronous flush of staged entropy and every endpoint, active-high.
`axis_req_i`	input	`drbg_axis_req_t`	32b AXI-Stream sink from the producer (valid/data/strb/tuser). Adapter drives tready; only beats with every tstrb bit set are accepted, and tuser is forwarded as edn_fips.
`axis_rsp_o`	output	`drbg_axis_rsp_t`	AXI-Stream ready toward the producer; high while the 4-entry staging FIFO has space, all tstrb bits are set and clear_i is low.
`edn_req_i`	input	`edn_pkg::edn_req_t [NUM_ENDPOINTS-1:0]`	Native EDN requests from clients.
`edn_rsp_o`	output	`edn_pkg::edn_rsp_t [NUM_ENDPOINTS-1:0]`	Native EDN responses to clients; ack, bus and fips are forced to zero during clear_i or that endpoint's reset.