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[edn] Improve FSM coverage #23092

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May 14, 2024
Merged

[edn] Improve FSM coverage #23092

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3d8c6e0
[edn/rtl] Make Error main SM state terminal again
vogelpi May 13, 2024
5c56c7f
[edn/dv] Fix FSM coverage holes
vogelpi May 13, 2024
4453fba
[edn/rtl] Fix Verilator lint errors and warnings
vogelpi May 13, 2024
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25 changes: 22 additions & 3 deletions hw/ip/edn/dv/env/seq_lib/edn_err_vseq.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,8 @@ class edn_err_vseq extends edn_base_vseq;
// If EDN is configured in Boot mode, randomly select one of the Boot states.
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(exp_state,
exp_state inside {BootLoadIns, BootInsAckWait, BootLoadGen,
BootGenAckWait, BootPulse, BootDone};)
BootGenAckWait, BootPulse, BootDone,
BootLoadUni, BootUniAckWait};)
end else if (cfg.auto_req_mode == MuBi4True) begin
// If instead EDN is configured in Auto mode, randomly select one of the Auto states.
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(exp_state,
Expand All @@ -80,8 +81,10 @@ class edn_err_vseq extends edn_base_vseq;
AutoCaptGenCnt, AutoSendGenCmd,
AutoCaptReseedCnt, AutoSendReseedCmd};)
end else begin
// If EDN is configured neither in Boot nor in Auto mode, select the SW state.
exp_state = SWPortMode;
// If EDN is configured neither in Boot nor in Auto mode, select among the remaining non-idle
// states.
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(exp_state,
exp_state inside {SWPortMode, RejectCsrngEntropy};)
end

`uvm_info(`gfn, $sformatf("Waiting for main_sm to reach state %s", exp_state.name()), UVM_HIGH)
Expand Down Expand Up @@ -137,6 +140,22 @@ class edn_err_vseq extends edn_base_vseq;
// Set wait_cmd_req_done to 0 since we don't want to wait for the ack.
wr_cmd(.cmd_type(edn_env_pkg::Sw), .acmd(csrng_pkg::INS), .clen(0),
.flags(MuBi4False), .glen(0), .mode(mode), .wait_for_ack(0));
end else if (cfg.boot_req_mode == MuBi4True &&
(exp_state == BootLoadUni || exp_state == BootUniAckWait)) begin
// The Uninstantiate command is automatically sent upon disabling boot mode (after
// entering the BootDone state).
ral.ctrl.boot_req_mode.set(prim_mubi_pkg::MuBi4False);
csr_update(.csr(ral.ctrl));
end
if (exp_state == RejectCsrngEntropy) begin
// Make sure the next CSRNG acknowledgement returns an error status.
cfg.m_csrng_agent_cfg.rsp_sts_err = csrng_pkg::CMD_STS_INVALID_ACMD;
// Trigger a CSRNG acknowledgement. For boot and auto mode, we should eventually get
// a CSRNG command acknowledgement anyway. In SW mode, we could trigger any command.
if (cfg.boot_req_mode != MuBi4True && cfg.auto_req_mode != MuBi4True) begin
wr_cmd(.cmd_type(edn_env_pkg::Sw), .acmd(csrng_pkg::INS), .clen(0),
.flags(MuBi4False), .glen(0), .mode(mode), .wait_for_ack(0));
end
end
end
join_none
Expand Down
8 changes: 5 additions & 3 deletions hw/ip/edn/rtl/edn_core.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -370,7 +370,7 @@ module edn_core import edn_pkg::*;

// CSRNG acknowledgement error status
assign csrng_ack_err = edn_enable_fo[CsrngAckErr] &&
csrng_cmd_i.csrng_rsp_sts && csrng_cmd_i.csrng_rsp_ack;
csrng_cmd_i.csrng_rsp_ack && (csrng_cmd_i.csrng_rsp_sts != csrng_pkg::CMD_STS_SUCCESS);
assign hw2reg.recov_alert_sts.csrng_ack_err.de = csrng_ack_err;
assign hw2reg.recov_alert_sts.csrng_ack_err.d = csrng_ack_err;

Expand Down Expand Up @@ -608,7 +608,8 @@ module edn_core import edn_pkg::*;
!edn_enable_fo[HwCmdSts] ? csrng_pkg::CMD_STS_SUCCESS :
sw_cmd_valid ? csrng_hw_cmd_sts_q :
(cs_cmd_req_vld_out_q && csrng_cmd_i.csrng_req_ready) ? csrng_pkg::CMD_STS_SUCCESS :
csrng_cmd_i.csrng_rsp_ack && csrng_cmd_i.csrng_rsp_sts ? csrng_cmd_i.csrng_rsp_sts :
csrng_cmd_i.csrng_rsp_ack && (csrng_cmd_i.csrng_rsp_sts != csrng_pkg::CMD_STS_SUCCESS) ?
csrng_cmd_i.csrng_rsp_sts :
csrng_hw_cmd_sts_q;
// Set the cmd_ack signal to high whenever a hardware command is acknowledged and set it
// to low whenever a new hardware command is issued to the CSRNG.
Expand Down Expand Up @@ -857,7 +858,8 @@ module edn_core import edn_pkg::*;

assign packer_cs_clr = !edn_enable_fo[CsrngPackerClr];
assign packer_cs_push = csrng_cmd_i.genbits_valid && !reject_csrng_entropy &&
!(csrng_cmd_i.csrng_rsp_sts && csrng_cmd_i.csrng_rsp_ack);
!((csrng_cmd_i.csrng_rsp_sts != csrng_pkg::CMD_STS_SUCCESS) &&
csrng_cmd_i.csrng_rsp_ack);
assign packer_cs_wdata = csrng_cmd_i.genbits_bus;
assign csrng_cmd_o.genbits_ready = packer_cs_wready && !reject_csrng_entropy;
assign packer_cs_rready = packer_arb_valid;
Expand Down
9 changes: 5 additions & 4 deletions hw/ip/edn/rtl/edn_main_sm.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -6,9 +6,8 @@
//
// does hardware-based csrng app interface command requests

module edn_main_sm import edn_pkg::*; #(
localparam int StateWidth = 9
) (
module edn_main_sm import edn_pkg::*;
(
input logic clk_i,
input logic rst_ni,

Expand Down Expand Up @@ -181,7 +180,9 @@ module edn_main_sm import edn_pkg::*; #(
endcase

if (local_escalate_i || csrng_ack_err_i) begin
state_d = local_escalate_i ? Error : RejectCsrngEntropy;
// Either move into RejectCsrngEntropy or Error but don't move out of Error as it's terminal.
state_d = local_escalate_i ? Error :
state_q == Error ? Error : RejectCsrngEntropy;
Comment on lines +183 to +185
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Great that you caught that.

// Tie off outputs, except for main_sm_err_o and reject_csrng_entropy_o.
boot_wr_ins_cmd_o = 1'b0;
boot_wr_gen_cmd_o = 1'b0;
Expand Down