[rom_ctrl,dv] Scramble when randomizing ROM contents
This ensures that the ECC bits actually match what we expect, which is
needed in the smoke sequence. There's a design bug which means that we
were discarding those bits and replacing them with ones that are
correct. Oops!
Putting the right checksum in place means that we can now fix the
design without everything breaking.
Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
diff --git a/hw/ip/rom_ctrl/dv/env/seq_lib/rom_ctrl_base_vseq.sv b/hw/ip/rom_ctrl/dv/env/seq_lib/rom_ctrl_base_vseq.sv
index b1c2cd7..54064df 100644
--- a/hw/ip/rom_ctrl/dv/env/seq_lib/rom_ctrl_base_vseq.sv
+++ b/hw/ip/rom_ctrl/dv/env/seq_lib/rom_ctrl_base_vseq.sv
@@ -35,8 +35,21 @@
// Task to build a random rom in memory
virtual task rom_ctrl_mem_init();
- // randomize the memory contents
- cfg.mem_bkdr_util_h.randomize_mem();
+ bit [31:0] rnd_data;
+
+ // Randomize the memory contents.
+ //
+ // We can't just use the mem_bkdr_util randomize_mem function because that doesn't obey the
+ // scrambling key. This wouldn't be a problem (the memory is supposed to be random!), except
+ // that we also need to pick ECC values that match.
+ for (int i = 0; i < rom_ctrl_reg_pkg::ROM_CTRL_ROM_SIZE / 4; i++) begin
+ `DV_CHECK_STD_RANDOMIZE_FATAL(rnd_data)
+ cfg.mem_bkdr_util_h.rom_encrypt_write32_integ(i * 4,
+ rnd_data,
+ RND_CNST_SCR_KEY,
+ RND_CNST_SCR_NONCE,
+ 1'b1);
+ end
endtask
// Task to perform `num_ops` fully randomized memory transactions.
