Last commit before I nuke it

src/application_wrapper/cache/application_wrapper_cache_l1.sv

@@ -88,7 +88,7 @@ logic [31:0] cache_miss_count, cache_miss_count_next;
 // reset counter
 logic [INDEX_W-1:0] clear_counter, clear_counter_next;
 
-enum logic [2:0] {RESET, CLEAR, IDLE, READY, EVICT, READ} prev_state, state, state_next;
+enum logic [2:0] {RESET, CLEAR, IDLE, READY, EVICT, READ, WAIT_CLEAN_UNIQUE} prev_state, state, state_next;
 
 always_ff @(posedge i_clk) begin
     if (i_rst) begin
@@ -263,6 +263,23 @@ always_comb begin
                 // We are accessing something we just wrote to
 
                 if (latched_we) begin
+                    // if we are writing to a shared cacheline, we must make it unique first!
+                    if (current_data.shared) begin
+                        o_rdy = '0;
+
+                        o_cache_cmd = CACHE_CLEAN_UNIQUE;
+                        o_cache_valid = '1;
+
+                        latched_we_next = we_d1;
+                        latched_data_next = data_d1;
+
+                        read_index_next = index_d1;
+                        read_offset_next = offset_d1;
+
+
+                        state_next = WAIT_CLEAN_UNIQUE;
+                    end
+
                     write_data = current_data;
 
                     write_data[offset_d1*8 +: 8] = latched_data;
@@ -284,9 +301,9 @@ always_comb begin
                     end else begin
                         o_data = current_data[offset_d1*8 +: 8];
                     end
+                    o_rdy = '1;
                 end
 
-                o_rdy = '1;
             end
         end
 
@@ -303,14 +320,18 @@ always_comb begin
 
         READ: begin
             o_cache_addr = read_address;
-            o_cache_cmd = CACHE_READ;
+            if (latched_we) begin
+                o_cache_cmd = CACHE_READ_UNIQUE;
+            end else begin
+                o_cache_cmd = CACHE_READ_SHARED;
+            end
             o_cache_valid = '1;
 
             write_index = read_index;
             write_data = i_cache_data;
             write_meta_tag.tag = read_address[31:INDEX_W+OFFSET_W];
             write_meta_tag.valid = '1;
-            write_meta_tag.shared = '0;
+            write_meta_tag.shared = ~latched_we; // if we are about to write, then we requested unique
             write_meta_tag.clean = ~latched_we; // if we are about to write, then mark dirty
 
             data_write_enable = i_cache_rdy;
@@ -327,6 +348,28 @@ always_comb begin
             end            
         end
 
+        WAIT_CLEAN_UNIQUE: begin
+            // Write data after making it unique
+            if (i_cache_rdy) begin
+                write_data[offset_d1*8 +: 8] = latched_data;
+                data_write_enable = i_cache_rdy;
+
+                meta_tag_write_enable = i_cache_rdy;
+                write_meta_tag.tag = read_address[31:INDEX_W+OFFSET_W];
+                write_meta_tag.valid = '1;
+                write_meta_tag.shared = '0;
+                write_meta_tag.clean = '0;
+
+                write_index = index_d1;
+
+                if (index == write_index) begin
+                    current_data_next = write_data;
+                end
+
+                state_next = READY;
+            end
+        end
+
         default: begin
             state_next = READY;
         end
@@ -361,6 +404,20 @@ end
     already be dirty anyway.
 */
 
+/*
+
+    In order for this to be a coherent requester, we need to adjust the protocol slightly
+    
+    * CPU Requests data to READ: Send ReadShared request
+    * CPU Requests data to WRITE: Send ReadUnique request
+    * CPU Writes to data already in cache: CleanUnique
+    * Clean cacheline overwritten: Send Evict request
+    * Dirty cacheline overwritten: Send WriteBackFull request
+
+    The cache <-> CHI interface is handled by a separate module.
+*/
+
+
 
 
 endmodule

src/application_wrapper/cache/application_wrapper_cache_pkg.sv

@@ -10,10 +10,12 @@ package application_wrapper_cache_pkg;
         logic write_through;
     } page_table_entry_t;
 
-    typedef enum logic [1:0] {
+    typedef enum logic [2:0] {
         CACHE_NONE,
-        CACHE_READ,
-        CACHE_WRITE
+        CACHE_READ_SHARED,
+        CACHE_READ_UNIQUE,
+        CACHE_WRITE,
+        CACHE_CLEAN_UNIQUE
     } cache_cmd_e;
 
 endpackage