SPI fixes, and remove reset controller and PLL

We need to expose all the input, output and output enable SPI lines
in order to use QSPI.

Remove the reset controller and PLL, since we are driving these
directly from caravel.

fpga/top-caravel.vhdl

@@ -15,9 +15,9 @@ entity toplevel is
         HAS_FPU            : boolean  := false;
         NO_BRAM            : boolean  := false;
         DISABLE_FLATTEN_CORE : boolean := false;
-        SPI_FLASH_OFFSET   : integer := 4194304;
+        SPI_FLASH_OFFSET   : integer := 0;
-        SPI_FLASH_DEF_CKDV : natural := 1;
+        SPI_FLASH_DEF_CKDV : natural := 4;
-        SPI_FLASH_DEF_QUAD : boolean := true;
+        SPI_FLASH_DEF_QUAD : boolean := false;
         LOG_LENGTH         : natural := 16;
         UART_IS_16550      : boolean := true;
         HAS_UART1          : boolean := false;
@@ -36,12 +36,11 @@ entity toplevel is
         uart1_rxd : in std_ulogic;
 
         -- SPI
-        spi_flash_cs_n   : out std_ulogic;
+        spi_flash_cs_n    : out std_ulogic;
-        spi_flash_clk    : out std_ulogic;
+        spi_flash_clk     : out std_ulogic;
-        spi_flash_mosi   : inout std_ulogic;
+        spi_flash_sdat_i  : in std_ulogic_vector(3 downto 0);
-        spi_flash_miso   : inout std_ulogic;
+        spi_flash_sdat_o  : out std_ulogic_vector(3 downto 0);
-        spi_flash_wp_n   : inout std_ulogic;
+        spi_flash_sdat_oe : out std_ulogic_vector(3 downto 0);
-        spi_flash_hold_n : inout std_ulogic;
 
         -- JTAG signals:
         jtag_tck  : in std_ulogic;
@@ -64,21 +63,14 @@ entity toplevel is
 end entity toplevel;
 
 architecture behaviour of toplevel is
+    -- reset signals
+    signal system_rst : std_ulogic;
 
-    -- Reset signals:
+    -- external bus wishbone connection
-    signal soc_rst : std_ulogic;
-    signal pll_rst : std_ulogic;
-
-    -- Internal clock signals:
-    signal system_clk        : std_ulogic;
-    signal system_clk_locked : std_ulogic;
-    signal ext_rst_n : std_ulogic;
-
-    -- wishbone over logic analyzer connection
     signal wb_dram_out : wishbone_master_out;
     signal wb_dram_in  : wishbone_slave_out;
 
-    -- Wishbone over LA
+    -- external bus
     signal wb_mc_adr   : wishbone_addr_type;
     signal wb_mc_dat_o : wishbone_data_type;
     signal wb_mc_cyc   : std_ulogic;
@@ -88,16 +80,10 @@ architecture behaviour of toplevel is
     signal wb_mc_dat_i : wishbone_data_type;
     signal wb_mc_ack   : std_ulogic;
     signal wb_mc_stall : std_ulogic;
-
-    -- SPI flash
-    signal spi_sck     : std_ulogic;
-    signal spi_cs_n    : std_ulogic;
-    signal spi_sdat_o  : std_ulogic_vector(3 downto 0);
-    signal spi_sdat_oe : std_ulogic_vector(3 downto 0);
-    signal spi_sdat_i  : std_ulogic_vector(3 downto 0);
-
 begin
 
+    system_rst <= not ext_rst when RESET_LOW else ext_rst;
+
     -- Main SoC
     soc0: entity work.soc
         generic map(
@@ -122,8 +108,8 @@ begin
             )
         port map (
             -- System signals
-            system_clk        => system_clk,
+            system_clk        => ext_clk,
-            rst               => soc_rst,
+            rst               => system_rst,
 
             -- UART signals
             uart0_txd         => uart0_txd,
@@ -134,11 +120,11 @@ begin
             uart1_rxd         => uart1_rxd,
 
             -- SPI signals
-            spi_flash_sck     => spi_sck,
+            spi_flash_sck     => spi_flash_clk,
-            spi_flash_cs_n    => spi_cs_n,
+            spi_flash_cs_n    => spi_flash_cs_n,
-            spi_flash_sdat_o  => spi_sdat_o,
+            spi_flash_sdat_o  => spi_flash_sdat_o,
-            spi_flash_sdat_oe => spi_sdat_oe,
+            spi_flash_sdat_oe => spi_flash_sdat_oe,
-            spi_flash_sdat_i  => spi_sdat_i,
+            spi_flash_sdat_i  => spi_flash_sdat_i,
 
             -- JTAG signals
             jtag_tck          => jtag_tck,
@@ -155,8 +141,6 @@ begin
 	    alt_reset            => alt_reset
             );
 
-    ext_rst_n <= not ext_rst;
-
     mc0: entity work.mc
 	generic map(
 	    WB_AW          => 32,        -- wishbone_addr_bits
@@ -168,8 +152,8 @@ begin
 					 -- chunk at top for config space.
 	    )
 	port map (
-	    clk	         => system_clk,
+	    clk	         => ext_clk,
-	    rst   	 => ext_rst_n,
+	    rst   	 => system_rst,
 
 	    wb_cyc       => wb_mc_cyc,
 	    wb_stb       => wb_mc_stb,
@@ -190,19 +174,7 @@ begin
 --	    int          => ob int
     );
 
-    -- SPI Flash
+    -- External bus wishbone
-    spi_flash_cs_n   <= spi_cs_n;
-    spi_flash_mosi   <= spi_sdat_o(0) when spi_sdat_oe(0) = '1' else 'Z';
-    spi_flash_miso   <= spi_sdat_o(1) when spi_sdat_oe(1) = '1' else 'Z';
-    spi_flash_wp_n   <= spi_sdat_o(2) when spi_sdat_oe(2) = '1' else 'Z';
-    spi_flash_hold_n <= spi_sdat_o(3) when spi_sdat_oe(3) = '1' else 'Z';
-    spi_sdat_i(0)    <= spi_flash_mosi;
-    spi_sdat_i(1)    <= spi_flash_miso;
-    spi_sdat_i(2)    <= spi_flash_wp_n;
-    spi_sdat_i(3)    <= spi_flash_hold_n;
-    spi_flash_clk    <= spi_sck;
-
-    -- Wishbone over LA
     wb_mc_adr      <= wb_dram_out.adr;
     wb_mc_dat_o    <= wb_dram_out.dat;
     wb_mc_cyc      <= wb_dram_out.cyc;
@@ -214,29 +186,4 @@ begin
     wb_dram_in.ack   <= wb_mc_ack;
     wb_dram_in.stall <= wb_mc_stall;
 
-    reset_controller: entity work.soc_reset
-        generic map(
-            RESET_LOW => RESET_LOW
-            )
-        port map(
-            ext_clk => ext_clk,
-            pll_clk => system_clk,
-            pll_locked_in => system_clk_locked,
-            ext_rst_in => ext_rst,
-            pll_rst_out => pll_rst,
-            rst_out => soc_rst
-            );
-
-    clkgen: entity work.clock_generator
-        generic map(
-            CLK_INPUT_HZ => CLK_INPUT,
-            CLK_OUTPUT_HZ => CLK_FREQUENCY
-            )
-        port map(
-            ext_clk => ext_clk,
-            pll_rst_in => pll_rst,
-            pll_clk_out => system_clk,
-            pll_locked_out => system_clk_locked
-            );
-
 end architecture behaviour;