Add _very incomplete_ AMBA 3 AHB Lite widget

This is just a start on the first widget. It is still very limited and
not yet functional in any way.

srdl2sv/components/addrmap.py

@@ -130,7 +130,14 @@ class AddrMap(Component):
         # Remove comma from last port entry
         output_ports_rtl[-1] = output_ports_rtl[-1].rstrip(',')
 
-        import_package_list = []
+        # Define packages to be included. Always include the
+        # b2w and w2b defines.
+        import_package_list = [
+            AddrMap.templ_dict['import_package']['rtl'].format(
+                name = 'srdl2sv_widget'),
+            '\n'
+            ]
+
         try:
             for x in self.get_package_names():
                 import_package_list.append(
@@ -139,10 +146,11 @@ class AddrMap(Component):
 
                 import_package_list.append('\n')
 
-            import_package_list.pop()
         except IndexError:
             pass
 
+        import_package_list.pop()
+        
         import getpass
         import socket
         import time

srdl2sv/components/templates/addrmap.yaml

@@ -69,8 +69,6 @@ module_declaration:
         <<INDENT>>
         // Clock & Resets
         input  reg_clk,
-        input  bus_clk,
-        input  bus_rst_n,
         {resets} 
 
         // Inputs
@@ -115,13 +113,13 @@ read_mux:
       // Read multiplexer
       always_comb
       begin
-      case(addr)
+      case(b2r.addr)
       {list_of_cases}
       endcase
       end
 default_mux_case:
     rtl: |-
-        default: sw_rd_bus = 0;
+        default: r2b.data = 0;
 list_of_mux_cases:
     rtl: |-
-        32'd{}: sw_rd_bus = {};
+        32'd{}: r2b.data = {};

srdl2sv/components/templates/fields.yaml

@@ -29,9 +29,9 @@ sw_access_field_swwel:
         begin
 sw_access_byte: 
     rtl: |-
-        if (byte_enable[{i}])
+        if (b2r.byte_en[{i}])
         <<INDENT>>
-        {path}_q{genvars}[{msb_field}:{lsb_field}] <= sw_wr_bus[{msb_bus}:{lsb_bus}];
+        {path}_q{genvars}[{msb_field}:{lsb_field}] <= b2r.data[{msb_bus}:{lsb_bus}];
         <<UNINDENT>>
     signals:
         - name: '{path}_q'
@@ -114,33 +114,33 @@ end_field_ff:
         end // of {path}'s always_ff
 OnWriteType.woset: 
     rtl: |-
-        if (byte_enable[{i}]) // woset property
+        if (b2r.byte_en[{i}]) // woset property
         begin
-        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] | sw_wr_bus[{msb_bus}:{lsb_bus}];
+        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] | b2r.data[{msb_bus}:{lsb_bus}];
         end
 OnWriteType.woclr: 
     rtl: |-
-        if (byte_enable[{i}]) // woclr property
+        if (b2r.byte_en[{i}]) // woclr property
         begin
-        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] & ~sw_wr_bus[{msb_bus}:{lsb_bus}];
+        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] & ~b2r.data[{msb_bus}:{lsb_bus}];
         end
 OnWriteType.wot: 
     rtl: |-
-        if (byte_enable[{i}]) // wot property
+        if (b2r.byte_en[{i}]) // wot property
         begin
-        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] ^ sw_wr_bus[{msb_bus}:{lsb_bus}];
+        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] ^ b2r.data[{msb_bus}:{lsb_bus}];
         end
 OnWriteType.wzs: 
     rtl: |-
-        if (byte_enable[{i}]) // wzs property
+        if (b2r.byte_en[{i}]) // wzs property
         begin
-        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] & sw_wr_bus[{msb_bus}:{lsb_bus}];
+        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] & b2r.data[{msb_bus}:{lsb_bus}];
         end
 OnWriteType.wzt: 
     rtl: |-
-        if (byte_enable[{i}]) // wzt property
+        if (b2r.byte_en[{i}]) // wzt property
         begin
-        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] ~^ sw_wr_bus[{msb_bus}:{lsb_bus}];
+        {path}_q{genvars}[{msb_field}:{lsb_field}] <= {path}_q{genvars}[{msb_field}:{lsb_field}] ~^ b2r.data[{msb_bus}:{lsb_bus}];
         end
 OnWriteType.wclr: 
     rtl: |-
@@ -210,7 +210,7 @@ swacc_assign:
     rtl: |-
 
         // Combinational block to generate swacc-output signals
-        assign {path}_swacc{genvars} = ({path_wo_field}__any_alias_sw_wr{genvars} || {path_wo_field}__any_alias_sw_rd{genvars}) && |byte_enable[{msbyte}:{lsbyte}];
+        assign {path}_swacc{genvars} = ({path_wo_field}__any_alias_sw_wr{genvars} || {path_wo_field}__any_alias_sw_rd{genvars}) && |b2r.byte_en[{msbyte}:{lsbyte}];
     output_ports:
         - name: '{path}_swacc'
           signal_type: 'logic'
@@ -228,7 +228,7 @@ swmod_always_comb:
           signal_type: 'logic'
 swmod_assign: 
     rtl: |-
-        {path}_swmod{genvars} |= {path_wo_field}__any_alias_sw_{rd_wr}{genvars} && |byte_enable[{msbyte}:{lsbyte}];
+        {path}_swmod{genvars} |= {path_wo_field}__any_alias_sw_{rd_wr}{genvars} && |b2r.byte_en[{msbyte}:{lsbyte}];
     output_ports:
         - name: '{path}_swmod'
           signal_type: 'logic'

srdl2sv/components/templates/regs.yaml

@@ -3,9 +3,9 @@ rw_wire_assign_1_dim:
     rtl: |
 
         // Register-activation for '{path}' {alias}
-        assign {path}_accss = addr == {addr};
+        assign {path}_accss = b2r.addr == {addr};
-        assign {path}_sw_wr = {path}_accss && r_vld;
+        assign {path}_sw_wr = {path}_accss && b2r.r_vld;
-        assign {path}_sw_rd = {path}_accss && w_vld;
+        assign {path}_sw_rd = {path}_accss && b2r.w_vld;
     signals:
         - name: '{path}_sw_wr'
           signal_type: 'logic'
@@ -17,9 +17,9 @@ rw_wire_assign_multi_dim:
     rtl: |-
 
         // Register-activation for '{path}' {alias}
-        assign {path}_accss{genvars} = addr == {addr}+({genvars_sum});
+        assign {path}_accss{genvars} = b2r.addr == {addr}+({genvars_sum});
-        assign {path}_sw_wr{genvars} = {path}_accss{genvars} && r_vld;
+        assign {path}_sw_wr{genvars} = {path}_accss{genvars} && b2r.r_vld;
-        assign {path}_sw_rd{genvars} = {path}_accss{genvars} && w_vld;
+        assign {path}_sw_rd{genvars} = {path}_accss{genvars} && b2r.w_vld;
     signals:
         - name: '{path}_sw_wr'
           signal_type: 'logic'

srdl2sv/components/widgets/amba3ahblite.sv

@@ -1,35 +1,174 @@
+/*
+ * Copyright 2021 Dennis Potter <dennis@dennispotter.eu>
+ * 
+ * Permission is hereby granted, free of charge, to any person 
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without 
+ * restriction, including without limitation the rights to use, 
+ * copy, modify, merge, publish, distribute, sublicense, and/or 
+ * sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following 
+ * conditions:
+ * 
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ * 
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
 module amba3ahblite_widget
+    import srdl2sv_widget_pkg::*;
+#(
+    parameter FLOP_IN = 0, // Set to '1' to flop input from the AHB bus. This is meant
+                           // to help meet timing. Don't use this to synchronize the input.
+    parameter SYNC_IO = 0  // Set to '1' to in case HCLK and bus_clk are asynchronous
+                           // By default, mainly for it to directly work in simulations,
+                           // it will double-flops based on always_ff-blocks. To replace
+                           // this module with a proper MTBF-optimized double flop cell,
+                           // the contents of the synchronizer module `srdl2sv_sync.sv`
+                           // shall be updated
+)
 (
     // Register clock
-    input         bus_clk,
+    input               reg_clk,
-    input         bus_rst_n,
 
     // Outputs to internal logic
-    output [31:0] addr,
+    output b2r_t        b2r,
-    output        w_vld,
-    output        r_vld,
-    output [ 3:0] byte_enable,
-    output [31:0] sw_wr_bus,
 
     // Inputs from internal logic
-    input  [31:0] sw_rd_bus,
+    input  r2b_t        r2b,
  
     // Bus protocol
-    input         HRESETn,
+    input               HRESETn,
-    input         HCLK,
+    input               HCLK,
-    input  [31:0] HADDR,
+    input               HSEL,
-    input         HWRITE,
+    input  [31:0]       HADDR,
-    input  [ 2:0] HSIZE,
+    input               HWRITE,
-    input  [ 2:0] HBURST,
+    input  [ 2:0]       HSIZE,
-    input  [ 3:0] HPROT,
+    input  [ 2:0]       HBURST,
-    input  [ 1:0] HTRANS,
+    input  [ 3:0]       HPROT,
-    input         HMASTLOCK,
+    input  [ 1:0]       HTRANS,
-    input         HREADY,
+    input  [31:0]       HWDATA,
+    input               HREADY,
 
-    output        HREADYOUT,
+    output logic        HREADYOUT,
-    output        HRESP,
+    output logic        HRESP,
-    output [31:0] HRDATA
+    output logic [31:0] HRDATA
 );
 
+    // TODO: Add synchronizer logic
+ 
+    /***
+     * Translate HWRITE & HSEL into a write/read operation for the register logic
+     ***/
+    logic r_vld_next;
+    logic w_vld_next;
+
+    always_comb
+    begin
+        w_vld_next = 1'b0;
+        r_vld_next = 1'b0;
+
+        if (HWRITE)
+            w_vld_next = HSEL;
+        else
+            r_vld_next = HSEL;
+    end
+
+    /***
+     * Determine the number of active bytes
+     ***/
+    logic [3:0] b2r_byte_en_next;
+
+    always_comb
+    begin
+        case (HTRANS)
+            3'b000 : b2r_byte_en_next = 4'b0001;
+            3'b001 : b2r_byte_en_next = 4'b0011;
+            3'b010 : b2r_byte_en_next = 4'b1111;
+            // TODO: Implement larger sizes
+            default: b2r_byte_en_next = 4'b1111;
+        endcase
+    end
+
+    /***
+     * Flop or sync input if required
+     ***/
+    generate
+        if (FLOP_IN)
+        begin
+            always_ff @(posedge HCLK or negedge HRESETn)
+            if (!HRESETn)
+            begin
+                b2r.r_vld <= 1'b0;
+                b2r.w_vld <= 1'b0;
+            end
+            else
+            begin
+                b2r.r_vld <= r_vld_next;
+                b2r.w_vld <= w_vld_next;
+            end
+
+            always_ff @(posedge HCLK)
+                if (HWRITE)
+                begin
+                    b2r.data    <= HWDATA;
+                    b2r.byte_en <= b2r_byte_en_next;
+                end
+        end
+        else
+        begin
+            assign b2r.r_vld = r_vld_next;
+            assign b2r.w_vld = w_vld_next;
+            assign b2r.data  = HWDATA;
+        end
+    endgenerate
+
+    /***
+     * Keep track of an ungoing transaction
+     ***/
+    logic reg_busy_q;
+
+    always_ff @(posedge HCLK or negedge HRESETn)
+        if (!HRESETn)
+            reg_busy_q <= 1'b0;
+        else if ((b2r.r_vld || b2r.w_vld) && !r2b.rdy)
+            reg_busy_q <= 1'b1;
+        else if (r2b.rdy)
+            reg_busy_q <= 1'b0;
+
+    assign HREADYOUT = !reg_busy_q;
+
+    /***
+     * Return to AHB bus once the register block is ready
+     ***/
+    // Return actual data
+    logic ongoing_read_q;
+
+    always_ff @(posedge HCLK or negedge HRESETn)
+        if (!HRESETn)
+            ongoing_read_q <= 1'b0;
+        else if (b2r.r_vld && !r2b.rdy)
+            ongoing_read_q <= 1'b1;
+        else if (r2b.rdy)
+            ongoing_read_q <= 1'b0;
+
+    always_ff @(posedge HCLK)
+        if ((b2r.r_vld || ongoing_read_q) && r2b.rdy)
+            HRDATA <= r2b.data;
+
+    // Did an error occur while reading?
+    always_ff @(posedge HCLK or negedge HRESETn)
+        if (!HRESETn)
+            HRESP <= 1'b0;
+        else
+            HRESP <= r2b.err;
 
 endmodule

srdl2sv/components/widgets/amba3ahblite.yaml

@@ -1,24 +1,30 @@
 # This file only contains the instantiation of the module
 module_instantiation:
     rtl: |-
-        /****************************
+        /*******************************************************************
          * AMBA 3 AHB Lite Widget
-         ****************************/
+         * ======================
+         * Naming conventions
+         *    - r2b.*     -> Signals from registers to bus
+         *    - b2r.*     -> Signals from bus to registers
+         *    - H*        -> Signals as defined in AMBA3 AHB Lite 
+         *                   specification
+         *    - bus_clk   -> Clock that that drives signals on bus
+         *    - reg_clk   -> Clock that drives register flops
+         *    - bus_rst_n -> Asynchronous reset that resets only the bus (but
+         *                   (not the registers). The deassertion of this
+         *                   reset shall be synchronized to bus_clk
+         *******************************************************************/
         amba3ahblite_widget
         amba3ahblite_widget_inst
-            (// Clocks & Resets
+            (// Register clock
-             .bus_clk,
+             .reg_clk,
-             .bus_rst_n,
 
              // Outputs to internal logic
-             .addr,
+             .b2r,
-             .w_vld,
-             .r_vld,
-             .byte_enable,
-             .sw_wr_bus,
 
              // Inputs from internal logic
-             .sw_rd_bus,
+             .r2b,
  
              // Bus protocol
              .HRESETn,
@@ -29,25 +35,18 @@ module_instantiation:
              .HBURST,
              .HPROT,
              .HTRANS,
-             .HMASTLOCK,
+             .HWDATA,
              .HREADY,
+             .HSEL,
 
              .HREADYOUT,
              .HRESP,
              .HRDATA);
     signals:
-        - name: 'addr'
+        - name: 'b2r'
-          signal_type: 'logic [31:0]'
+          signal_type: 'b2r_t'
-        - name: 'w_vld'
+        - name: 'r2b'
-          signal_type: 'logic'
+          signal_type: 'r2b_t'
-        - name: 'r_vld'
-          signal_type: 'logic'
-        - name: 'byte_enable'
-          signal_type: 'logic [ 3:0]'
-        - name: 'sw_wr_bus'
-          signal_type: 'logic [31:0]'
-        - name: 'sw_rd_bus'
-          signal_type: 'logic [31:0]'
     input_ports:
         - name: 'HRESETn'
           signal_type: ''
@@ -65,10 +64,12 @@ module_instantiation:
           signal_type: '[3:0]'
         - name: 'HTRANS'
           signal_type: '[1:0]'
-        - name: 'HMASTLOCK'
+        - name: 'HWDATA'
-          signal_type: ''
+          signal_type: '[31:0]'
         - name: 'HREADY'
           signal_type: ''
+        - name: 'HSEL'
+          signal_type: ''
     output_ports:
         - name: 'HREADYOUT'
           signal_type: ''

srdl2sv/components/widgets/srdl2sv_widget_pkg.sv

@@ -0,0 +1,17 @@
+package srdl2sv_widget_pkg;
+
+typedef struct {
+    logic [31:0] addr;
+    logic [31:0] data;
+    logic        w_vld;
+    logic        r_vld;
+    logic [ 3:0] byte_en;
+} b2r_t;
+
+typedef struct {
+    logic [31:0] data;
+    logic        rdy;
+    logic        err;
+} r2b_t;
+
+endpackage

srdl2sv/main.py

@@ -58,11 +58,12 @@ if __name__ == "__main__":
     out_addrmap_file = "{}/{}.sv".format(config['output_dir'], addrmap.name)
 
     with open(out_addrmap_file, 'w') as file:
-        file.write(
+        print(
             addrmap.get_rtl(
                 tab_width=config['tab_width'],
                 real_tabs=config['real_tabs']
-            )
+            ),
+            file=file
         )
 
         logger.info('Succesfully created "{}"'.format(out_addrmap_file))
@@ -75,7 +76,7 @@ if __name__ == "__main__":
     ).items():
         if value:
             with open('{}/{}_pkg.sv'.format(config['output_dir'], key), 'w') as file:
-                file.write(value)
+                print(value, file=file)
 
     # Copy over widget RTL from widget directory
     widget_rtl = pkg_resources.read_text(widgets, '{}.sv'.format(config['bus']))
@@ -83,9 +84,19 @@ if __name__ == "__main__":
     out_widget_file = "{}/{}.sv".format(config['output_dir'], config['bus'])
 
     with open(out_widget_file, 'w') as file:
-        file.write(widget_rtl)
+        print(widget_rtl, file=file)
 
     logger.info("Selected, implemented, and copied '{}' widget".format(config['bus']))
 
+    # Copy over generic srdl2sv_widget_pkg
+    widget_if_rtl = pkg_resources.read_text(widgets, 'srdl2sv_widget_pkg.sv')
+
+    out_widget_if_file = "{}/srdl2sv_widget_pkg.sv".format(config['output_dir'])
+
+    with open(out_widget_if_file, 'w') as file:
+        print(widget_if_rtl,file=file)
+
+    logger.info("Copied 'srdl2sv_widget_pkg.sv")
+
     # Print elapsed time
     logger.info("Elapsed time: %f seconds", time.time() - start)