From 1aba6fb17aa00682e397e1960daf9b3885061cd0 Mon Sep 17 00:00:00 2001
From: matthewcroughan <matt@croughan.sh>
Date: Sat, 9 Jul 2022 04:28:56 +0100
Subject: [PATCH] flake: use regexp and flake inputs to automate kernel
 building

---
 base.nix   |  5 -----
 flake.lock | 31 ++++++++++++++++++++++++-------
 flake.nix  | 12 ++++++++++--
 kernel.nix | 22 ++++++++++++++--------
 4 files changed, 48 insertions(+), 22 deletions(-)

diff --git a/base.nix b/base.nix
index 7ca7c8d..0645f16 100644
--- a/base.nix
+++ b/base.nix
@@ -1,10 +1,5 @@
 { config, pkgs, lib, ... }:
 {
-  # Use the kernel from ./kernel.nix
-  boot.kernelPackages = let
-    linux_VisionFive = pkgs.callPackage ./kernel.nix { };
-  in lib.mkForce (pkgs.recurseIntoAttrs (pkgs.linuxPackagesFor linux_VisionFive));
-
   # Remove ZFS
   boot.supportedFilesystems = lib.mkForce [ "btrfs" "reiserfs" "vfat" "f2fs" "xfs" "ntfs" "cifs" "ext4" "vfat" ];
 
diff --git a/flake.lock b/flake.lock
index 76ca4e7..1640872 100644
--- a/flake.lock
+++ b/flake.lock
@@ -54,16 +54,16 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1652789813,
-        "narHash": "sha256-90QPw85Vl9+YWQpM/zRjb0/OYI+IODimC4LZufpCIh4=",
-        "owner": "Madouura",
+        "lastModified": 1657311595,
+        "narHash": "sha256-P/uhx5z7pW8OlpJzeShM7iBw7obrgv8CNLRP3G2xcG0=",
+        "owner": "matthewcroughan",
         "repo": "nixpkgs",
-        "rev": "aff8bd5ce0a12ee22402cd9bc6b3c437f0845345",
+        "rev": "6fd612ce3a656b1bcf5a1222c63294dcfcbb5361",
         "type": "github"
       },
       "original": {
-        "owner": "Madouura",
-        "ref": "dev/linux-riscv",
+        "owner": "matthewcroughan",
+        "ref": "mc/visionfive-nix",
         "repo": "nixpkgs",
         "type": "github"
       }
@@ -74,7 +74,24 @@
         "jh7100_recovery_binary": "jh7100_recovery_binary",
         "jh7100_secondBoot": "jh7100_secondBoot",
         "jh71xx-tools": "jh71xx-tools",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "vendor-kernel": "vendor-kernel"
+      }
+    },
+    "vendor-kernel": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1657015117,
+        "narHash": "sha256-WkJBcyAj1sDMZ8s/JqSAOV+CvXHwGYQrs9cLnOv0BkQ=",
+        "owner": "starfive-tech",
+        "repo": "linux",
+        "rev": "943858df470556d0b7f3b31fcc10931603f0f3cc",
+        "type": "github"
+      },
+      "original": {
+        "owner": "starfive-tech",
+        "repo": "linux",
+        "type": "github"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 3fdb61d..66100b3 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,6 +1,10 @@
 {
   inputs = {
     nixpkgs.url = "github:matthewcroughan/nixpkgs/mc/visionfive-nix";
+    vendor-kernel = {
+      url = "github:starfive-tech/linux";
+      flake = false;
+    };
     jh7100_ddrinit = {
       url = "https://github.com/starfive-tech/JH7100_ddrinit/releases/download/ddrinit-2133-211102/ddrinit-2133-211102.bin.out";
       flake = false;
@@ -18,17 +22,21 @@
       flake = false;
     };
   };
-  outputs = { self, nixpkgs, jh71xx-tools, jh7100_recovery_binary, jh7100_secondBoot, jh7100_ddrinit }:
+  outputs = { self, nixpkgs, jh71xx-tools, jh7100_recovery_binary, jh7100_secondBoot, jh7100_ddrinit, vendor-kernel }:
     let
       system = "x86_64-linux";
-      pkgs = import nixpkgs { inherit system; };
+      pkgs = import nixpkgs { inherit system; overlays = [ self.overlay ]; };
       modules = [
+        { nixpkgs.overlays = [ self.overlay ]; }
         "${nixpkgs}/nixos/modules/installer/sd-card/sd-image-riscv64-visionfive-installer.nix"
         ./base.nix
         ./configuration.nix
       ];
     in
     {
+      overlay = final: prev: {
+        linuxPackages_visionfive = final.linuxPackagesFor ((final.callPackage ./kernel.nix { inherit vendor-kernel; }).override { patches = []; });
+      };
       apps.${system} = {
         flashBootloader =
           let
diff --git a/kernel.nix b/kernel.nix
index 4f519cb..1063444 100644
--- a/kernel.nix
+++ b/kernel.nix
@@ -1,26 +1,33 @@
 { lib
 , fetchFromGitHub
 , buildLinux
+, vendor-kernel
 , ... } @ args:
 
 let
-  modDirVersion = "5.18.5";
+  kernelVersion = rec {
+    # Fully constructed string, example: "5.10.0-rc5".
+    string = "${version + "." + patchlevel + "." + sublevel + (lib.optionalString (extraversion != "") extraversion)}";
+    file = "${vendor-kernel}/Makefile";
+    version = toString (builtins.match ".+VERSION = ([0-9]+).+" (builtins.readFile file));
+    patchlevel = toString (builtins.match ".+PATCHLEVEL = ([0-9]+).+" (builtins.readFile file));
+    sublevel = toString (builtins.match ".+SUBLEVEL = ([0-9]+).+" (builtins.readFile file));
+    # rc, next, etc.
+    extraversion = toString (builtins.match ".+EXTRAVERSION = ([a-z0-9-]+).+" (builtins.readFile file));
+  };
+  modDirVersion = "${kernelVersion.string}";
 in buildLinux (args // {
   inherit modDirVersion;
   version = "${modDirVersion}-visionfive";
 
-  src = fetchFromGitHub {
-    owner = "starfive-tech";
-    repo = "linux";
-    rev = "8fb50a9b3e5d401d4ec169c858e8b7ba0a542955";
-    sha256 = "sha256-kjOoNJhmmQdpmtx0m1ZovH3mj2x4NB6iInEknxZq8Dw=";
-  };
+  src = vendor-kernel;
 
   kernelPatches = [];
 
   defconfig = "starfive_jh7100_fedora_defconfig";
 
   structuredExtraConfig = with lib.kernel; {
+    KEXEC = yes;
     SERIAL_8250_DW = yes;
     PINCTRL_STARFIVE = yes;
 
@@ -34,7 +41,6 @@ in buildLinux (args // {
   };
 
   extraMeta = {
-    branch = "visionfive-5.18.y";
     description = "Linux kernel for StarFive's JH7100 RISC-V SoC (VisionFive)";
     platforms = [ "riscv64-linux" ];
     hydraPlatforms = [ "riscv64-linux" ];