From c8efa952f9d76c058972f12007f9945ff7bf3ee8 Mon Sep 17 00:00:00 2001
From: Rodrigo Arias Mallo <rodrigo.arias@bsc.es>
Date: Tue, 25 Jun 2024 11:11:05 +0200
Subject: [PATCH] Add configuration for Lagarto Ox

---
 flake.nix      |  35 +++++++++++++
 lagarto-ox.nix | 132 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 167 insertions(+)
 create mode 100644 lagarto-ox.nix

diff --git a/flake.nix b/flake.nix
index f549cf1..cef84f7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -58,6 +58,17 @@
           ./no-compressed.nix
         ];
       };
+
+      # FPGA Lagarto Ox CPU
+      lagarto-ox = nixosSystem {
+        specialArgs = { inherit self; };
+        system = "${system}";
+        modules = [
+          ./configuration.nix
+          ./lagarto-ox.nix
+          ./no-compressed.nix
+        ];
+      };
     };
 
     # A development shell with QEMU ready to boot the RISC-V system in an x86
@@ -97,5 +108,29 @@
         echo " UBOOT_ENV = $UBOOT_ENV"
       '';
     };
+
+    devShells.x86_64-linux.lagarto-ox =
+    let
+      nixosconf = self.nixosConfigurations.lagarto-ox;
+      syspkgs = nixosconf.pkgs;
+      build = nixosconf.config.system.build;
+    in syspkgs.mkShell {
+      pname = "lagarto-ox-shell";
+      TOPLEVEL = build.toplevel;
+      OPENSBI = syspkgs.opensbi;
+      KERNEL = build.kernel;
+      INITRD = build.initialRamdisk;
+      ROOTFS = build.sdImage;
+      UBOOT_ENV = syspkgs.uboot-env;
+      shellHook = ''
+        echo "Here are the current system pieces:"
+        echo " TOPLEVEL  = $TOPLEVEL"
+        echo " KERNEL    = $KERNEL"
+        echo " OPENSBI   = $OPENSBI"
+        echo " INITRD    = $INITRD"
+        echo " ROOTFS    = $ROOTFS"
+        echo " UBOOT_ENV = $UBOOT_ENV"
+      '';
+    };
   };
 }
diff --git a/lagarto-ox.nix b/lagarto-ox.nix
new file mode 100644
index 0000000..51359ba
--- /dev/null
+++ b/lagarto-ox.nix
@@ -0,0 +1,132 @@
+{ config, lib, pkgs, modulesPath, ... }:
+
+{
+  imports = [
+    "${modulesPath}/installer/sd-card/sd-image.nix"
+  ];
+
+  #boot.kernelPackages = pkgs.linuxPackages_latest;
+  boot = {
+    kernelPatches = [
+      {
+        name = assert false; "sbi-early-console";
+        patch = null;
+        extraConfig =
+        # Early console via SBI
+        ''
+          RISCV_SBI y
+          RISCV_SBI_V01 y
+          SERIAL_EARLYCON y
+          SERIAL_EARLYCON_RISCV_SBI y
+          HVC_DRIVER y
+          HVC_RISCV_SBI y
+        ''
+        # Allows regions of persistent memory to be described in the device-tree.
+        + ''
+          OF_PMEM y
+        ''
+        # Allow you to use a contiguous range of reserved memory as one or more
+        # persistent block devices (/dev/pmem0)
+        + ''
+          LIBNVDIMM y
+          BLK_DEV_PMEM y
+        ''
+        ;
+      }
+    ];
+
+    initrd = {
+      # Avoid zstd as we don't have the tools in "cucu" machine
+      compressor = "gzip";
+      kernelModules = [ ];
+    };
+
+    loader = {
+      grub.enable = false;
+      generic-extlinux-compatible.enable = true;
+    };
+  };
+
+  # No network
+  services.openssh.enable = false;
+
+  # Run getty on /dev/console and restartt until it works
+  systemd.services."serial-getty@console" = {
+    enable = true;
+    wantedBy = [ "getty.target" ]; # to start at boot
+    serviceConfig.Restart = "always";
+  };
+
+  # Disable hvc0 as it is racing for the same console
+  systemd.services."serial-getty@hvc0" = {
+    enable = lib.mkForce false;
+    wantedBy = lib.mkForce [ ];
+  };
+
+  sdImage = {
+    # The image will be loaded as-is in memory, so no compression
+    compressImage = false;
+    imageName = "rootfs.img";
+    # Not needed for now
+    expandOnBoot = false;
+    populateFirmwareCommands = "";
+    populateRootCommands = ''
+      mkdir -p ./files/boot
+      ${config.boot.loader.generic-extlinux-compatible.populateCmd} \
+        -c ${config.system.build.toplevel} \
+        -d ./files/boot
+    '';
+  };
+
+  nixpkgs.overlays = [ (final: prev: {
+    uboot = prev.ubootQemuRiscv64Smode.override {
+      filesToInstall = [ "u-boot.bin" "u-boot-nodtb.bin" ];
+      extraConfig = ''
+        CONFIG_RISCV_ISA_C=n
+        CONFIG_REQUIRE_SERIAL_CONSOLE=n
+        CONFIG_SERIAL_SEARCH_ALL=y
+        CONFIG_OF_CONTROL=y
+        CONFIG_OF_BOARD=y
+        CONFIG_OF_HAS_PRIOR_STAGE=y
+        CONFIG_BLKMAP=y
+        CONFIG_CMD_BLKMAP=y
+        CONFIG_SBI_V01=y
+        CONFIG_DEBUG_UART=y
+        CONFIG_DEBUG_UART_ANNOUNCE=y
+        CONFIG_DEBUG_SBI_CONSOLE=y
+      '';
+    };
+
+    uboot-env = let
+      init = "${config.system.build.toplevel}/init";
+      initrd = "${config.system.build.initialRamdisk}/initrd";
+    in prev.runCommand "uboot.txt" {} ''
+      cat > $out <<EOF
+      # Create pmem of 3 GiB [0x140000000, 0x200000000)
+      fdt mknode / pmem@0x140000000
+      fdt set /pmem@0x140000000 compatible "pmem-region"
+      fdt set /pmem@0x140000000 reg <0x1 0x40000000 0x0 0xc0000000>
+
+      # Reduce memory to 3 GiB [0x80000000, 0x140000000)
+      fdt set /memory@80000000  reg <0x0 0x80000000 0x0 0xc0000000>
+
+      # Set kernel options
+      setenv bootargs "root=/dev/ram0 loglevel=7 debug rw earlycon=sbi boot.trace console=hvc0 init=${init}"
+
+      EOF
+
+      # Populate the bood commands from the initrd size
+      echo "# Boot system" >> $out
+      echo "setenv ramdisk_size $(stat --format %s $(readlink -f ${initrd}))" >> $out
+      echo 'booti ''${kernel_addr_r} ''${ramdisk_addr_r}:''${ramdisk_size} ''${fdtcontroladdr}' >> $out
+    '';
+
+    opensbi = prev.opensbi.overrideAttrs (old: {
+      makeFlags = old.makeFlags ++ [
+        "PLATFORM=fpga/openpiton"
+        "FW_PAYLOAD_PATH=${final.uboot}/u-boot-nodtb.bin"
+      ];
+      patches = [ ./opensbi-lagarto-hun.patch ];
+    });
+  }) ];
+}