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[dv] fetch_enable_seq tweaks

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Previously the time over which fetch enable was disabled was randomized
at the start of the sequence and kept constant throught. Now it is
randomized for every `send_req`.

Stop generating FetchEnableOn as a possible fetch_enable value to set
and use the SecureIbex parameter to decide if full randomisation off all
of the non FetchEnableOn MUBI values if needed or we just always switch
between FetchEnableOn/FetchEnableOff

Tweaks the default min/max delay values for how long fetch remains
disabled.
This commit is contained in:
Greg Chadwick 2022-10-07 15:11:37 +01:00 • committed by Greg Chadwick
parent 27907d1d4a
commit 12952cfe13
1 changed files with 24 additions and 16 deletions
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40
dv/uvm/core_ibex/tests/core_ibex_new_seq_lib.sv
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@ -246,31 +246,39 @@ class fetch_enable_seq extends core_base_new_seq#(irq_seq_item);
`uvm_object_utils(fetch_enable_seq)
`uvm_object_new
ibex_pkg::fetch_enable_t fetch_enable;
int unsigned on_bias_pc = 50;
int unsigned max_delay = 500;
int unsigned min_delay = 75;
rand int unsigned off_delay = 0;
int unsigned min_delay = 1;
bit all_off_values = 0;
virtual task body();
dut_vif.dut_cb.fetch_enable <= ibex_pkg::FetchEnableOn;
if(off_delay == 0) begin
`DV_CHECK_MEMBER_RANDOMIZE_WITH_FATAL(off_delay,
// with {"CONSTRAINTS"}
off_delay inside {[min_delay : max_delay]};)
// SecureIbex configurations use a MUBI value for fetch enable so there are multiple off values,
// all should be tested. For other configurations only the bottom bit of the signal is used so
// there is a single off value
if (!uvm_config_db#(bit)::get(null, "", "SecureIbex", all_off_values)) begin
all_off_values = 0;
end
dut_vif.dut_cb.fetch_enable <= ibex_pkg::FetchEnableOn;
super.body();
endtask: body
virtual task send_req();
`DV_CHECK_MEMBER_RANDOMIZE_WITH_FATAL(fetch_enable,
// with {"CONSTRAINTS"}
fetch_enable dist {ibex_pkg::FetchEnableOn :/ on_bias_pc,
[0:15] :/ 100 - on_bias_pc};)
`uvm_info(`gfn, "Sending fetch enable request", UVM_LOW)
`uvm_info(`gfn, $sformatf("fetch_enable = %d", fetch_enable), UVM_LOW)
ibex_pkg::fetch_enable_t fetch_enable_off;
int unsigned off_delay;
dut_vif.dut_cb.fetch_enable <= fetch_enable;
if (all_off_values) begin
// Randomise the MUBI fetch_enable value to be one of the many possible off values
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(fetch_enable_off,
fetch_enable_off != ibex_pkg::FetchEnableOn;)
end else begin
// Otherwise use single fixed off value
fetch_enable_off = ibex_pkg::FetchEnableOff;
end
`DV_CHECK_STD_RANDOMIZE_WITH_FATAL(off_delay,
off_delay inside {[min_delay : max_delay]};)
dut_vif.dut_cb.fetch_enable <= fetch_enable_off;
clk_vif.wait_clks(off_delay);
dut_vif.dut_cb.fetch_enable <= ibex_pkg::FetchEnableOn;