[hdl] handle host 32-bit address overflow in L2P DMA master

5f010f90 · Dimitris Lampridis · f2863fc1 · 5f010f90 · 5f010f90
Commit 5f010f90 authored Sep 02, 2019 by Dimitris Lampridis
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Showing with 66 additions and 12 deletions

l2p_dma_master.vhd hdl/rtl/l2p_dma_master.vhd +23 -11

main.sv hdl/sim/example_tb/main.sv +43 -1

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--- a/hdl/rtl/l2p_dma_master.vhd
+++ b/hdl/rtl/l2p_dma_master.vhd
@@ -86,7 +86,14 @@ architecture behavioral of l2p_dma_master is
    ---------------------
    -- Constants
    ---------------------
-    constant c_L2P_MAX_PAYLOAD : integer := 32;
+    -- L2P_MAX_PAYLOAD must be a power of 2 for easier 32-bit address overflow check.
+    constant c_L2P_MAX_PAYLOAD_NBITS : integer := 7;
+    constant c_L2P_MAX_PAYLOAD_BYTES : integer := 2 ** c_L2P_MAX_PAYLOAD_NBITS;
+    constant c_L2P_MAX_PAYLOAD_WORDS : integer := c_L2P_MAX_PAYLOAD_BYTES / 4;
+    constant c_L2P_A32_OVERFLOW_MASK : std_logic_vector(31 downto 0) :=
+      not std_logic_vector(to_unsigned(c_L2P_MAX_PAYLOAD_BYTES - 1, 32));
    constant c_TIMEOUT         : integer := 2000;
    -- how many pending WB requests to allow without ACK
@@ -330,13 +337,13 @@ begin
            l2p_byte_swap   <= dma_ctrl_byte_swap_i;
            l2p_last_packet <= '0';
          elsif (l2p_dma_current_state = L2P_SETUP) then
-            if (l2p_len_cnt > c_L2P_MAX_PAYLOAD) then
+            if (l2p_len_cnt > c_L2P_MAX_PAYLOAD_WORDS) then
-              l2p_data_cnt    <= TO_UNSIGNED(c_L2P_MAX_PAYLOAD, 13);
+              l2p_data_cnt    <= TO_UNSIGNED(c_L2P_MAX_PAYLOAD_WORDS, 13);
-              l2p_len_header  <= TO_UNSIGNED(c_L2P_MAX_PAYLOAD, 13);
+              l2p_len_header  <= TO_UNSIGNED(c_L2P_MAX_PAYLOAD_WORDS, 13);
              l2p_last_packet <= '0';
-            elsif (l2p_len_cnt = c_L2P_MAX_PAYLOAD) then
+            elsif (l2p_len_cnt = c_L2P_MAX_PAYLOAD_WORDS) then
-              l2p_data_cnt    <= TO_UNSIGNED(c_L2P_MAX_PAYLOAD, 13);
+              l2p_data_cnt    <= TO_UNSIGNED(c_L2P_MAX_PAYLOAD_WORDS, 13);
-              l2p_len_header  <= TO_UNSIGNED(c_L2P_MAX_PAYLOAD, 13);
+              l2p_len_header  <= TO_UNSIGNED(c_L2P_MAX_PAYLOAD_WORDS, 13);
              l2p_last_packet <= '1';
            else
              l2p_data_cnt    <= l2p_len_cnt(12 downto 0);
@@ -349,10 +356,15 @@ begin
            end if;
          elsif (l2p_dma_current_state = L2P_LAST_DATA) then
            if (l2p_last_packet = '0') then
-              -- Increase Address
+              -- Increase Address, check for overflow
-              -- TODO Not overflow safe !
+              if (l2p_address_l and (c_L2P_A32_OVERFLOW_MASK)) = c_L2P_A32_OVERFLOW_MASK then
-              l2p_address_l <= std_logic_vector(unsigned(l2p_address_l) + (c_L2P_MAX_PAYLOAD * 4));
+                l2p_address_h <= std_logic_vector(unsigned(l2p_address_h) + 1);
-              l2p_len_cnt   <= l2p_len_cnt - c_L2P_MAX_PAYLOAD;
+                l2p_address_l(31 downto c_L2P_MAX_PAYLOAD_NBITS) <= (others => '0');
+              else
+                l2p_address_l <= std_logic_vector(
+                  unsigned(l2p_address_l) + (c_L2P_MAX_PAYLOAD_BYTES));
+              end if;
+              l2p_len_cnt   <= l2p_len_cnt - c_L2P_MAX_PAYLOAD_WORDS;
            else
              l2p_len_cnt <= (others => '0');
            end if;

--- a/hdl/sim/example_tb/main.sv
+++ b/hdl/sim/example_tb/main.sv
@@ -153,7 +153,7 @@ module main;
   initial begin
      automatic int ntest = 1;
-      const     int tests = 7;
+      const     int tests = 8;
      uint32_t addr, val, expected;
@@ -321,6 +321,48 @@ module main;
         #1us;
      end
+      $write("Test %0d/%0d: 256B read over DMA with 32bit host address overflow: ",
+             ntest++, tests);
+      acc.write('h14, 'h100); // count
+      acc.write('h20, 'h00); // attrib
+      acc.write('h0c, 'hffffff80); // hstartL
+      acc.write('h10, 'h00000000); // hstartH
+      acc.write('h00, 'h01); // start
+      // Transfer will be split internally by L2P DMA master in two requests, the first
+      // one with a 32-bit adress starting at ffff_ff80 and the next one with a 64-bit
+      // address starting at 1_0000_0000
+      @(posedge DUT.cmp_wrapped_gn4124.ldm_arb_dframe);
+      @(posedge DUT.cmp_wrapped_gn4124.sys_clk);
+      val_check("Host address overflow header", 1, DUT.cmp_wrapped_gn4124.ldm_arb_data, 'h02ff0020);
+      @(posedge DUT.cmp_wrapped_gn4124.sys_clk);
+      val_check("Host address overflow address", 1, DUT.cmp_wrapped_gn4124.ldm_arb_data, 'hffffff80);
+      @(posedge DUT.cmp_wrapped_gn4124.ldm_arb_dframe);
+      @(posedge DUT.cmp_wrapped_gn4124.sys_clk);
+      val_check("Host address overflow header", 2, DUT.cmp_wrapped_gn4124.ldm_arb_data, 'h03ff0020);
+      @(posedge DUT.cmp_wrapped_gn4124.sys_clk);
+      val_check("Host address overflow address high", 2, DUT.cmp_wrapped_gn4124.ldm_arb_data, 1);
+      @(posedge DUT.cmp_wrapped_gn4124.sys_clk);
+      val_check("Host address overflow address low", 2, DUT.cmp_wrapped_gn4124.ldm_arb_data, 0);
+      @(posedge dma_irq);
+      //  Check irq status
+      reg_check('h04, 'h04);
+      if (dma_irq != 1'b1)
+        $fatal(1, "dma irq should be 1");
+      // clear irq
+      acc.write('h04, 'h04);
+      reg_check('h04, 'h00);
+      if (dma_irq != 1'b0)
+        $fatal(1, "dma irq should be 0");
+      repeat(4) @(posedge clk_125m);
+      $write("PASS\n");
      $display();
      $display("Simulation PASSED");