Properly vendor in mem_model from OpenTitan

This removes the manually copied version at dv/uvm/core_ibex/common
and vendors things properly now that the vendor tool supports such
things (this picks up the same OpenTitan version as the previous
commit: lowRISC/opentitan@067272a2).

doc/verification.rst

@@ -46,8 +46,8 @@ execution.
 Memory Model
 """"""""""""
 
-The code can be found in the
-`dv/uvm/core_ibex/common/mem_model <https://github.com/lowRISC/ibex/tree/master/dv/uvm/core_ibex/common/mem_model>`_
+The code is vendored from OpenTitan and can be found in the
+`vendor/lowrisc_ip/mem_model <https://github.com/lowRISC/ibex/tree/master/vendor/lowrisc_ip/mem_model>`_
 directory.
 The testbench instantiates a single instance of this memory model that it loads the compiled
 assembly test program into at the beginning of each test.

dv/uvm/core_ibex/common/mem_model/mem_model.sv

@@ -1,57 +0,0 @@
-// Copyright lowRISC contributors.
-// Licensed under the Apache License, Version 2.0, see LICENSE for details.
-// SPDX-License-Identifier: Apache-2.0
-
-class mem_model#(parameter int ADDR_WIDTH = 32,
-                 parameter int DATA_WIDTH = 32) extends uvm_object;
-
-  typedef bit [ADDR_WIDTH-1:0] mem_addr_t;
-  typedef bit [DATA_WIDTH-1:0] mem_data_t;
-
-  bit [7:0] system_memory[mem_addr_t];
-
-  `uvm_object_param_utils(mem_model#(ADDR_WIDTH, DATA_WIDTH))
-
-  function new(string name="");
-    super.new(name);
-  endfunction
-
-  function bit [7:0] read_byte(mem_addr_t addr);
-    bit [7:0] data;
-    if(system_memory.exists(addr)) begin
-      data = system_memory[addr];
-      `uvm_info(get_full_name(),
-                $sformatf("Read Mem  : Addr[0x%0h], Data[0x%0h]", addr, data), UVM_HIGH)
-    end
-    else begin
-      `DV_CHECK_STD_RANDOMIZE_FATAL(data)
-      `uvm_error(get_full_name(), $sformatf("read to uninitialzed addr 0x%0h", addr))
-    end
-    return data;
-  endfunction
-
-  function void write_byte(mem_addr_t addr, bit[7:0] data);
-   `uvm_info(get_full_name(),
-             $sformatf("Write Mem : Addr[0x%0h], Data[0x%0h]", addr, data), UVM_HIGH)
-    system_memory[addr] = data;
-  endfunction
-
-  function void write(input mem_addr_t addr, mem_data_t data);
-    bit [7:0] byte_data;
-    for(int i=0; i<DATA_WIDTH/8; i++) begin
-      byte_data = data[7:0];
-      write_byte(addr+i, byte_data);
-      data = data >> 8;
-    end
-  endfunction
-
-  function mem_data_t read(mem_addr_t addr);
-    mem_data_t data;
-    for(int i=DATA_WIDTH/8-1; i>=0;  i--) begin
-      data = data << 8;
-      data[7:0] = read_byte(addr+i);
-    end
-    return data;
-  endfunction
-
-endclass

dv/uvm/core_ibex/ibex_dv.f

@@ -61,13 +61,13 @@ ${PRJ_DIR}/ibex/vendor/google_riscv-dv/src/riscv_signature_pkg.sv
 +incdir+${PRJ_DIR}/ibex/dv/uvm/core_ibex/tests
 +incdir+${PRJ_DIR}/ibex/dv/uvm/core_ibex/common/ibex_mem_intf_agent
 +incdir+${PRJ_DIR}/ibex/dv/uvm/core_ibex/common/irq_agent
-+incdir+${PRJ_DIR}/ibex/dv/uvm/core_ibex/common/mem_model
++incdir+${PRJ_DIR}/ibex/vendor/lowrisc_ip/mem_model
 +incdir+${PRJ_DIR}/ibex/vendor/lowrisc_ip/dv_utils
 ${PRJ_DIR}/ibex/dv/uvm/top_pkg/top_pkg.sv
 ${PRJ_DIR}/ibex/vendor/lowrisc_ip/common_ifs/clk_rst_if.sv
 ${PRJ_DIR}/ibex/vendor/lowrisc_ip/common_ifs/pins_if.sv
 ${PRJ_DIR}/ibex/vendor/lowrisc_ip/dv_utils/dv_utils_pkg.sv
-${PRJ_DIR}/ibex/dv/uvm/core_ibex/common/mem_model/mem_model_pkg.sv
+${PRJ_DIR}/ibex/vendor/lowrisc_ip/mem_model/mem_model_pkg.sv
 ${PRJ_DIR}/ibex/dv/uvm/core_ibex/common/ibex_mem_intf_agent/ibex_mem_intf.sv
 ${PRJ_DIR}/ibex/dv/uvm/core_ibex/common/ibex_mem_intf_agent/ibex_mem_intf_agent_pkg.sv
 ${PRJ_DIR}/ibex/dv/uvm/core_ibex/common/irq_agent/irq_if.sv

vendor/lowrisc_ip.vendor.hjson

@@ -15,6 +15,7 @@
         {from: "hw/dv/sv/csr_utils",   to: "csr_utils"},
         {from: "hw/dv/sv/dv_lib",      to: "dv_lib"},
         {from: "hw/dv/sv/dv_base_reg", to: "dv_base_reg"},
+        {from: "hw/dv/sv/mem_model",   to: "mem_model"},
         {from: "hw/dv/verilator",      to: "dv_verilator"},
 
         // We apply a patch to the top_pkg core file name when vendoring in

vendor/lowrisc_ip/mem_model/README.md

@@ -0,0 +1,26 @@
+## Memory Model
+The memory model UVC models a memory device which any host interface can read
+from or write to. It is implemented as a `uvm_object`, and instantiates an
+associative array of bytes `system_memory`. This class is paramterized by both
+the address width and the data width, and creates two `typedefs` to represent
+both, `mem_addr_t` and `mem_data_t`.
+The `mem_model` class has four main functions, which are detailed below.
+
+### `read_byte(mem_addr_t addr)`
+This function looks up the byte of data corresponding to the memory address
+passed in, and returns it. If the address does not exist in `system_memory`, it
+will randomize the returned data and throw a `UVM_ERROR`.
+
+### `write_byte(mem_addr_t addr, bit [7:0] data)`
+This function simply assigns the given data to the specified memory address
+location in `system_memory`.
+
+### `write(input mem_addr_t addr, mem_data_t data)`
+This function writes a full memory word of width `mem_data_t` to the specified
+address, breaking it down into a series of back-to-back calls to `write_byte()`
+to correctly byte-address the memory.
+
+### `read(mem_addr_t addr)`
+This function reads a full memory word of width `mem_data_t` from the specified
+address, breaking it down into a series of back-to-back calls to `read_byte()`
+to correctly byte-address the memory.

vendor/lowrisc_ip/mem_model/mem_model.core

@@ -8,7 +8,7 @@ description: "DV Memory Model"
 filesets:
   files_dv:
     depend:
-      - lowrisc:dv:dv_utils
+      - lowrisc:constants:top_pkg
     files:
       - mem_model_pkg.sv
       - mem_model.sv: {is_include_file: true}

vendor/lowrisc_ip/mem_model/mem_model.sv

@@ -0,0 +1,85 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+class mem_model #(int AddrWidth = top_pkg::TL_AW,
+                  int DataWidth = top_pkg::TL_DW,
+                  int MaskWidth = top_pkg::TL_DBW) extends uvm_object;
+
+  typedef bit [AddrWidth-1:0] mem_addr_t;
+  typedef bit [DataWidth-1:0] mem_data_t;
+  typedef bit [MaskWidth-1:0] mem_mask_t;
+
+  bit [7:0] system_memory[mem_addr_t];
+
+  `uvm_object_param_utils(mem_model#(AddrWidth, DataWidth))
+
+  `uvm_object_new
+
+  function int get_written_bytes();
+    return system_memory.size();
+  endfunction
+
+  function bit [7:0] read_byte(mem_addr_t addr);
+    bit [7:0] data;
+    if (system_memory.exists(addr)) begin
+      data = system_memory[addr];
+      `uvm_info(`gfn, $sformatf("Read Mem  : Addr[0x%0h], Data[0x%0h]", addr, data), UVM_HIGH)
+    end else begin
+      `DV_CHECK_STD_RANDOMIZE_FATAL(data)
+      `uvm_error(`gfn, $sformatf("read to uninitialzed addr 0x%0h", addr))
+    end
+    return data;
+  endfunction
+
+  function void write_byte(mem_addr_t addr, bit [7:0] data);
+   `uvm_info(`gfn, $sformatf("Write Mem : Addr[0x%0h], Data[0x%0h]", addr, data), UVM_HIGH)
+    system_memory[addr] = data;
+  endfunction
+
+  function void compare_byte(mem_addr_t addr, bit [7:0] act_data);
+   `uvm_info(`gfn, $sformatf("Compare Mem : Addr[0x%0h], Act Data[0x%0h], Exp Data[0x%0h]",
+                             addr, act_data, system_memory[addr]), UVM_HIGH)
+    system_memory[addr] = act_data;
+    `DV_CHECK_EQ(act_data, system_memory[addr], $sformatf("addr 0x%0h read out mismatch", addr))
+  endfunction
+
+  function void write(input mem_addr_t addr, mem_data_t data, mem_mask_t mask = '1);
+    bit [7:0] byte_data;
+    for (int i = 0; i < DataWidth / 8; i++) begin
+      if (mask[0]) begin
+        byte_data = data[7:0];
+        write_byte(addr + i, byte_data);
+      end
+      data = data >> 8;
+      mask = mask >> 1;
+    end
+  endfunction
+
+  function mem_data_t read(mem_addr_t addr, mem_mask_t mask = '1);
+    mem_data_t data;
+    for (int i = DataWidth / 8 - 1; i >= 0; i--) begin
+      data = data << 8;
+      if (mask[MaskWidth - 1]) data[7:0] = read_byte(addr + i);
+      else                     data[7:0] = 0;
+      mask = mask << 1;
+    end
+    return data;
+  endfunction
+
+  function void compare(mem_addr_t addr, mem_data_t act_data, mem_mask_t mask = '1);
+    bit [7:0] byte_data;
+    for (int i = 0; i < DataWidth / 8; i++) begin
+      byte_data = act_data[7:0];
+      if (mask[0]) begin
+        compare_byte(addr + i, byte_data);
+      end else begin
+        `DV_CHECK_EQ(byte_data, 0,
+                     $sformatf("addr 0x%0h masked data aren't 0, mask 0x%0h", addr, mask))
+      end
+      act_data = act_data>> 8;
+      mask = mask >> 1;
+    end
+  endfunction
+
+endclass