nixos/amdgpu: init module

nixos/modules/module-list.nix

@@ -549,6 +549,7 @@
   ./services/games/xonotic.nix
   ./services/hardware/acpid.nix
   ./services/hardware/actkbd.nix
+  ./services/hardware/amdgpu.nix
   ./services/hardware/amdvlk.nix
   ./services/hardware/argonone.nix
   ./services/hardware/asusd.nix

nixos/modules/services/hardware/amdgpu.nix

@@ -0,0 +1,43 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.hardware.amdgpu;
+in {
+  options.hardware.amdgpu = {
+    legacySupport.enable = lib.mkEnableOption ''
+      using `amdgpu` kernel driver instead of `radeon` for Southern Islands
+      (Radeon HD 7000) series and Sea Islands (Radeon HD 8000)
+      series cards. Note: this removes support for analog video outputs,
+      which is only available in the `radeon` driver
+    '';
+    initrd.enable = lib.mkEnableOption ''
+      loading `amdgpu` kernelModule in stage 1.
+      Can fix lower resolution in boot screen during initramfs phase
+    '';
+    opencl.enable = lib.mkEnableOption ''OpenCL support using ROCM runtime library'';
+    # cfg.amdvlk option is defined in ./amdvlk.nix module
+  };
+
+  config = {
+    boot.kernelParams = lib.optionals cfg.legacySupport.enable [
+      "amdgpu.si_support=1"
+      "amdgpu.cik_support=1"
+      "radeon.si_support=0"
+      "radeon.cik_support=0"
+    ];
+
+    boot.initrd.kernelModules = lib.optionals cfg.initrd.enable [ "amdgpu" ];
+
+    hardware.opengl = lib.mkIf cfg.opencl.enable {
+      enable = lib.mkDefault true;
+      extraPackages = [
+        pkgs.rocmPackages.clr
+        pkgs.rocmPackages.clr.icd
+      ];
+    };
+  };
+
+  meta = {
+    maintainers = with lib.maintainers; [ johnrtitor ];
+  };
+}