Add an extension to allow X values in tdata for null bytes.

Null bytes must be ignored by the slave and the interconnect is
allowed to remove these so checking that they contain valid data
is not necessary.

vunit/vhdl/verification_components/src/axi_stream_pkg.vhd

@@ -34,39 +34,42 @@ package axi_stream_pkg is
   type axi_stream_component_type_t is (null_component, default_component, custom_component);
 
   type axi_stream_protocol_checker_t is record
-    p_type        : axi_stream_component_type_t;
-    p_actor       : actor_t;
-    p_data_length : natural;
-    p_id_length   : natural;
-    p_dest_length : natural;
-    p_user_length : natural;
-    p_logger      : logger_t;
-    p_max_waits   : natural;
+    p_type                  : axi_stream_component_type_t;
+    p_actor                 : actor_t;
+    p_data_length           : natural;
+    p_id_length             : natural;
+    p_dest_length           : natural;
+    p_user_length           : natural;
+    p_logger                : logger_t;
+    p_max_waits             : natural;
+    p_allow_x_in_null_bytes : boolean;
   end record;
 
   constant null_axi_stream_protocol_checker : axi_stream_protocol_checker_t := (
-    p_type        => null_component,
-    p_actor       => null_actor,
-    p_data_length => 0,
-    p_id_length   => 0,
-    p_dest_length => 0,
-    p_user_length => 0,
-    p_logger      => null_logger,
-    p_max_waits   => 0
+    p_type                  => null_component,
+    p_actor                 => null_actor,
+    p_data_length           => 0,
+    p_id_length             => 0,
+    p_dest_length           => 0,
+    p_user_length           => 0,
+    p_logger                => null_logger,
+    p_max_waits             => 0,
+    p_allow_x_in_null_bytes => false
   );
 
   -- The default protocol checker is used to specify that the checker
   -- configuration is defined by the parent component into which the checker is
   -- instantiated.
   constant default_axi_stream_protocol_checker : axi_stream_protocol_checker_t := (
-    p_type        => default_component,
-    p_actor       => null_actor,
-    p_data_length => 0,
-    p_id_length   => 0,
-    p_dest_length => 0,
-    p_user_length => 0,
-    p_logger      => null_logger,
-    p_max_waits   => 0
+    p_type                  => default_component,
+    p_actor                 => null_actor,
+    p_data_length           => 0,
+    p_id_length             => 0,
+    p_dest_length           => 0,
+    p_user_length           => 0,
+    p_logger                => null_logger,
+    p_max_waits             => 0,
+    p_allow_x_in_null_bytes => false
   );
 
   type axi_stream_monitor_t is record
@@ -191,13 +194,14 @@ package axi_stream_pkg is
   ) return axi_stream_monitor_t;
 
   impure function new_axi_stream_protocol_checker(
-    data_length : natural;
-    id_length   : natural  := 0;
-    dest_length : natural  := 0;
-    user_length : natural  := 0;
-    logger      : logger_t := axi_stream_logger;
-    actor       : actor_t  := null_actor;
-    max_waits   : natural  := 16
+    data_length           : natural;
+    id_length             : natural  := 0;
+    dest_length           : natural  := 0;
+    user_length           : natural  := 0;
+    logger                : logger_t := axi_stream_logger;
+    actor                 : actor_t  := null_actor;
+    max_waits             : natural  := 16;
+    allow_x_in_null_bytes : boolean  := false
   ) return axi_stream_protocol_checker_t;
 
   impure function data_length(master : axi_stream_master_t) return natural;
@@ -469,24 +473,26 @@ package body axi_stream_pkg is
   end;
 
   impure function new_axi_stream_protocol_checker(
-      data_length : natural;
-      id_length   : natural  := 0;
-      dest_length : natural  := 0;
-      user_length : natural  := 0;
-      logger      : logger_t := axi_stream_logger;
-      actor       : actor_t  := null_actor;
-      max_waits   : natural  := 16
+      data_length           : natural;
+      id_length             : natural  := 0;
+      dest_length           : natural  := 0;
+      user_length           : natural  := 0;
+      logger                : logger_t := axi_stream_logger;
+      actor                 : actor_t  := null_actor;
+      max_waits             : natural  := 16;
+      allow_x_in_null_bytes : boolean := false
     ) return axi_stream_protocol_checker_t is
   begin
     return (
-      p_type        => custom_component,
-      p_actor       => actor,
-      p_data_length => data_length,
-      p_id_length   => id_length,
-      p_dest_length => dest_length,
-      p_user_length => user_length,
-      p_logger      => logger,
-      p_max_waits   => max_waits);
+      p_type                  => custom_component,
+      p_actor                 => actor,
+      p_data_length           => data_length,
+      p_id_length             => id_length,
+      p_dest_length           => dest_length,
+      p_user_length           => user_length,
+      p_logger                => logger,
+      p_max_waits             => max_waits,
+      p_allow_x_in_null_bytes => allow_x_in_null_bytes);
   end;
 
   impure function data_length(master : axi_stream_master_t) return natural is

vunit/vhdl/verification_components/src/axi_stream_protocol_checker.vhd

@@ -69,6 +69,20 @@ architecture a of axi_stream_protocol_checker is
   signal areset_n_d  : std_logic := '0';
   signal areset_rose : std_logic;
   signal not_tvalid  : std_logic;
+
+  signal tdata_normalized : std_logic_vector(tdata'range);
+
+  function normalize_tdata(data, strb, keep : std_logic_vector) return std_logic_vector is
+    variable ret : std_logic_vector(data'range);
+  begin
+    ret := data;
+    for i in keep'range loop
+      if keep(i) = '0' and strb(i) = '0' then
+        ret(i*8+7 downto i*8) := (others => '0');
+      end if;
+    end loop;
+    return ret;
+  end function;
 begin
   handshake_is_not_x <= '1' when not is_x(tvalid) and not is_x(tready) else '0';
 
@@ -112,7 +126,8 @@ begin
 
   -- AXI4STREAM_ERRM_TDATA_X A value of X on TDATA is not permitted when TVALID
   -- is HIGH
-  check_not_unknown(rule5_checker, aclk, tvalid, tdata, result("for tdata when tvalid is high"));
+  tdata_normalized <= normalize_tdata(tdata, tstrb, tkeep) when protocol_checker.p_allow_x_in_null_bytes else tdata;
+  check_not_unknown(rule5_checker, aclk, tvalid, tdata_normalized, result("for tdata when tvalid is high"));
 
   -- AXI4STREAM_ERRM_TLAST_X A value of X on TLAST is not permitted when TVALID
   -- is HIGH