From 1e3e16e5009d3f6c86682ef23c6f00da9ba60d99 Mon Sep 17 00:00:00 2001
From: Anton Blanchard <anton@linux.ibm.com>
Date: Fri, 13 Sep 2019 20:17:17 +1000
Subject: [PATCH] Add an icache testbench

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
---
 Makefile       |   6 ++-
 icache_tb.vhdl | 120 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 125 insertions(+), 1 deletion(-)
 create mode 100644 icache_tb.vhdl

diff --git a/Makefile b/Makefile
index 3c3836f..431170f 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,7 @@ GHDL=ghdl
 GHDLFLAGS=--std=08
 CFLAGS=-O2 -Wall
 
-all = core_tb simple_ram_behavioural_tb soc_reset_tb
+all = core_tb simple_ram_behavioural_tb soc_reset_tb icache_tb
 # XXX
 # loadstore_tb fetch_tb
 
@@ -27,6 +27,7 @@ glibc_random_helpers.o:
 glibc_random.o: glibc_random_helpers.o
 helpers.o:
 icache.o: common.o wishbone_types.o
+icache_tb.o: common.o wishbone_types.o icache.o simple_ram_behavioural.o
 insn_helpers.o:
 loadstore1.o: common.o
 loadstore2.o: common.o helpers.o wishbone_types.o
@@ -54,6 +55,9 @@ core_tb: core_tb.o simple_ram_behavioural_helpers_c.o sim_console_c.o
 fetch_tb: fetch_tb.o
 	$(GHDL) -e $(GHDLFLAGS) $@
 
+icache_tb: icache_tb.o
+	$(GHDL) -e $(GHDLFLAGS) -Wl,simple_ram_behavioural_helpers_c.o $@
+
 loadstore_tb: loadstore_tb.o
 	$(GHDL) -e $(GHDLFLAGS) $@
 
diff --git a/icache_tb.vhdl b/icache_tb.vhdl
new file mode 100644
index 0000000..4955177
--- /dev/null
+++ b/icache_tb.vhdl
@@ -0,0 +1,120 @@
+library ieee;
+use ieee.std_logic_1164.all;
+
+library work;
+use work.common.all;
+use work.wishbone_types.all;
+
+entity icache_tb is
+end icache_tb;
+
+architecture behave of icache_tb is
+    signal clk          : std_ulogic;
+    signal rst          : std_ulogic;
+
+    signal i_out        : Fetch2ToIcacheType;
+    signal i_in         : IcacheToFetch2Type;
+
+    signal wb_bram_in   : wishbone_master_out;
+    signal wb_bram_out  : wishbone_slave_out;
+
+    constant clk_period : time := 10 ns;
+begin
+    icache0: entity work.icache
+        generic map(
+            LINE_SIZE_DW => 8,
+            NUM_LINES => 4
+            )
+        port map(
+            clk => clk,
+            rst => rst,
+            i_in => i_out,
+            i_out => i_in,
+            wishbone_out => wb_bram_in,
+            wishbone_in => wb_bram_out
+            );
+
+    -- BRAM Memory slave
+    bram0: entity work.mw_soc_memory
+        generic map(
+            MEMORY_SIZE   => 128,
+            RAM_INIT_FILE => "icache_test.bin"
+            )
+        port map(
+            clk => clk,
+            rst => rst,
+            wishbone_in => wb_bram_in,
+            wishbone_out => wb_bram_out
+            );
+
+    clk_process: process
+    begin
+        clk <= '0';
+        wait for clk_period/2;
+        clk <= '1';
+        wait for clk_period/2;
+    end process;
+
+    rst_process: process
+    begin
+        rst <= '1';
+        wait for 2*clk_period;
+        rst <= '0';
+        wait;
+    end process;
+
+    stim: process
+    begin
+        i_out.req <= '0';
+        i_out.addr <= (others => '0');
+
+        wait for 4*clk_period;
+
+        i_out.req <= '1';
+        i_out.addr <= x"0000000000000004";
+
+        wait for 30*clk_period;
+
+        assert i_in.ack = '1';
+        assert i_in.insn = x"00000001";
+
+        i_out.req <= '0';
+
+        wait for clk_period;
+
+        -- hit
+        i_out.req <= '1';
+        i_out.addr <= x"0000000000000008";
+        wait for clk_period/2;
+        assert i_in.ack = '1';
+        assert i_in.insn = x"00000002";
+        wait for clk_period/2;
+
+        -- another miss
+        i_out.req <= '1';
+        i_out.addr <= x"0000000000000040";
+
+        wait for 30*clk_period;
+
+        assert i_in.ack = '1';
+        assert i_in.insn = x"00000010";
+
+        -- test something that aliases
+        i_out.req <= '1';
+        i_out.addr <= x"0000000000000100";
+        wait for clk_period/2;
+        assert i_in.ack = '0';
+        wait for clk_period/2;
+
+        wait for 30*clk_period;
+
+        assert i_in.ack = '1';
+        assert i_in.insn = x"00000040";
+
+        i_out.req <= '0';
+
+        assert false report "end of test" severity failure;
+        wait;
+
+    end process;
+end;