acorn: Add support for the Acorn CLE 215+

This is a NiteFury based PCIe M2 form-factor board originally
used for mining. It contains a speed grade 2 Artix 7 200T,
1GB of DDR3 and 32MB of flash.

The serial port is routed to pin 2 (RX) and 3 (TX) of the P2
connector (pin 1 is GND).

Note: Only 16MB of flash is currently usable until code is added
to configure the flash controller to use 4-bytes address commands
on that part.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

litedram/gen-src/acorn-cle-215.yml

@@ -0,0 +1,42 @@
+# This file is Copyright (c) 2018-2019 Florent Kermarrec <florent@enjoy-digital.fr>
+# License: BSD
+
+{
+    # General ------------------------------------------------------------------
+    "cpu":        "None",  # Type of CPU used for init/calib (vexriscv, lm32)
+    "cpu_variant":"standard",
+    "speedgrade": -2,          # FPGA speedgrade
+    "memtype":    "DDR3",      # DRAM type
+
+    # PHY ----------------------------------------------------------------------
+    "cmd_delay":       0,             # Command additional delay (in taps)
+    "cmd_latency":     0,             # Command additional latency
+    "sdram_module":    "MT41K512M16", # SDRAM modules of the board or SO-DIMM
+    "sdram_module_nb": 2,             # Number of byte groups
+    "sdram_rank_nb":   1,             # Number of ranks
+    "sdram_phy":       "A7DDRPHY",    # Type of FPGA PHY
+
+    # Electrical ---------------------------------------------------------------
+    "rtt_nom": "60ohm",  # Nominal termination
+    "rtt_wr":  "60ohm",  # Write termination
+    "ron":     "34ohm",  # Output driver impedance
+
+    # Frequency ----------------------------------------------------------------
+    "input_clk_freq":   200e6, # Input clock frequency
+    "sys_clk_freq":     100e6, # System clock frequency (DDR_clk = 4 x sys_clk)
+    "iodelay_clk_freq": 200e6, # IODELAYs reference clock frequency
+
+    # Core ---------------------------------------------------------------------
+    "cmd_buffer_depth": 16,    # Depth of the command buffer
+
+    # User Ports ---------------------------------------------------------------
+    "user_ports": {
+        "native_0": {
+            "type": "native",
+        },
+    },
+
+    # CSR Port -----------------------------------------------------------------
+    "csr_alignment"  : 32,
+    "csr_data_width" : 32,
+}

litedram/gen-src/generate.py

@@ -140,7 +140,7 @@ def generate_one(t):
 
 def main():
 
-    targets = ['arty','nexys-video', 'genesys2', 'sim']
+    targets = ['arty','nexys-video', 'genesys2', 'acorn-cle-215', 'sim']
     for t in targets:
         generate_one(t)
     

litedram/generated/acorn-cle-215/litedram-initmem.vhdl

@@ -0,0 +1,123 @@
+library ieee;
+use ieee.std_logic_1164.all;
+use ieee.numeric_std.all;
+use std.textio.all;
+
+library work;
+use work.wishbone_types.all;
+use work.utils.all;
+
+entity dram_init_mem is
+    generic (
+        EXTRA_PAYLOAD_FILE : string   := "";
+        EXTRA_PAYLOAD_SIZE : integer  := 0
+        );
+    port (
+        clk     : in std_ulogic;
+        wb_in   : in wb_io_master_out;
+        wb_out  : out wb_io_slave_out
+      );
+end entity dram_init_mem;
+
+architecture rtl of dram_init_mem is
+
+    constant INIT_RAM_SIZE    : integer := 24576;
+    constant RND_PAYLOAD_SIZE : integer := round_up(EXTRA_PAYLOAD_SIZE, 8);
+    constant TOTAL_RAM_SIZE   : integer := INIT_RAM_SIZE + RND_PAYLOAD_SIZE;
+    constant INIT_RAM_ABITS   : integer := log2ceil(TOTAL_RAM_SIZE-1);
+    constant INIT_RAM_FILE    : string := "litedram_core.init";
+
+    type ram_t is array(0 to (TOTAL_RAM_SIZE / 4) - 1) of std_logic_vector(31 downto 0);
+
+    -- XXX FIXME: Have a single init function called twice with
+    -- an offset as argument
+    procedure init_load_payload(ram: inout ram_t; filename: string) is
+        file payload_file : text open read_mode is filename;
+        variable ram_line : line;
+        variable temp_word : std_logic_vector(63 downto 0);
+    begin
+        for i in 0 to RND_PAYLOAD_SIZE-1 loop
+            exit when endfile(payload_file);
+            readline(payload_file, ram_line);
+            hread(ram_line, temp_word);
+            ram((INIT_RAM_SIZE/4) + i*2) := temp_word(31 downto 0);
+            ram((INIT_RAM_SIZE/4) + i*2+1) := temp_word(63 downto 32);
+        end loop;
+        assert endfile(payload_file) report "Payload too big !" severity failure;
+    end procedure;
+
+    impure function init_load_ram(name : string) return ram_t is
+        file ram_file : text open read_mode is name;
+        variable temp_word : std_logic_vector(63 downto 0);
+        variable temp_ram : ram_t := (others => (others => '0'));
+        variable ram_line : line;
+    begin
+        report "Payload size:" & integer'image(EXTRA_PAYLOAD_SIZE) &
+            " rounded to:" & integer'image(RND_PAYLOAD_SIZE);
+        report "Total RAM size:" & integer'image(TOTAL_RAM_SIZE) &
+            " bytes using " & integer'image(INIT_RAM_ABITS) &
+            " address bits";
+        for i in 0 to (INIT_RAM_SIZE/8)-1 loop
+            exit when endfile(ram_file);
+            readline(ram_file, ram_line);
+            hread(ram_line, temp_word);
+            temp_ram(i*2) := temp_word(31 downto 0);
+            temp_ram(i*2+1) := temp_word(63 downto 32);
+        end loop;
+        if RND_PAYLOAD_SIZE /= 0 then
+            init_load_payload(temp_ram, EXTRA_PAYLOAD_FILE);
+        end if;
+        return temp_ram;
+    end function;
+
+    impure function init_zero return ram_t is
+        variable temp_ram : ram_t := (others => (others => '0'));
+    begin
+        return temp_ram;
+    end function;
+
+    impure function initialize_ram(filename: string) return ram_t is
+    begin
+        report "Opening file " & filename;
+        if filename'length = 0 then
+            return init_zero;
+        else
+            return init_load_ram(filename);
+        end if;
+    end function;
+    signal init_ram : ram_t := initialize_ram(INIT_RAM_FILE);
+
+    attribute ram_style : string;
+    attribute ram_style of init_ram: signal is "block";
+
+    signal obuf : std_ulogic_vector(31 downto 0);
+    signal oack : std_ulogic;
+begin
+
+    init_ram_0: process(clk)
+        variable adr  : integer;
+    begin
+        if rising_edge(clk) then
+            oack <= '0';
+            if (wb_in.cyc and wb_in.stb) = '1' then
+                adr := to_integer((unsigned(wb_in.adr(INIT_RAM_ABITS-1 downto 2))));
+                if wb_in.we = '0' then
+                   obuf <= init_ram(adr);
+                else
+                    for i in 0 to 3 loop
+                        if wb_in.sel(i) = '1' then
+                            init_ram(adr)(((i + 1) * 8) - 1 downto i * 8) <=
+                                wb_in.dat(((i + 1) * 8) - 1 downto i * 8);
+                        end if;
+                    end loop;
+                end if;
+                oack <= '1';
+            end if;
+            wb_out.ack <= oack;
+            wb_out.dat <= obuf;
+        end if;
+    end process;
+
+    wb_out.stall <= '0';
+
+end architecture rtl;