From 6d191b73ae20d449c8daae8188b9474b84498011 Mon Sep 17 00:00:00 2001
From: Daniel Barlow <dan@telent.net>
Date: Thu, 2 Mar 2023 23:01:26 +0000
Subject: [PATCH] add outputs.flashable - flashable firmware.bin

---
 devices/gl-ar750/default.nix |  6 +++
 kernel/dtb.nix               |  4 ++
 modules/base.nix             |  1 +
 modules/flashable.nix        | 71 ++++++++++++++++++++++++++++++++++++
 modules/outputs.nix          |  1 +
 modules/tftpboot.nix         |  1 +
 rotuer.nix                   |  1 +
 7 files changed, 85 insertions(+)
 create mode 100644 modules/flashable.nix

diff --git a/devices/gl-ar750/default.nix b/devices/gl-ar750/default.nix
index c15f642..f77b448 100644
--- a/devices/gl-ar750/default.nix
+++ b/devices/gl-ar750/default.nix
@@ -91,6 +91,12 @@
         defaultOutput = "tftproot";
         loadAddress = "0x80060000";
         entryPoint  = "0x80060000";
+        flash = {
+          address = "0x9F060000";
+          size ="0xfa0000";
+        };
+        rootDevice = "1f05";
+
         networkInterfaces = {
           lan = interface { device = "eth0"; };
           wan = interface { device = "eth1"; };
diff --git a/kernel/dtb.nix b/kernel/dtb.nix
index b53d525..f971cec 100644
--- a/kernel/dtb.nix
+++ b/kernel/dtb.nix
@@ -1,18 +1,22 @@
 {
   stdenv
 , dtc
+, lib
 }:
 { dts
 , includes
+, commandLine
 }:let
   cppDtSearchFlags = builtins.concatStringsSep " " (map (f: "-I${f}") includes);
   dtcSearchFlags = builtins.concatStringsSep " " (map (f: "-i${f}") includes);
+  cmdline = lib.concatStringsSep " " commandLine;
 in stdenv.mkDerivation {
   name = "dtb";
   phases = [ "buildPhase" ];
   nativeBuildInputs = [ dtc ];
   buildPhase = ''
     ${stdenv.cc.targetPrefix}cpp -nostdinc -x assembler-with-cpp ${cppDtSearchFlags} -undef -D__DTS__  -o dtb.tmp ${dts}
+    echo '/{ chosen { bootargs = ${builtins.toJSON cmdline}; }; };'  >> dtb.tmp
     dtc ${dtcSearchFlags} -I dts  -O dtb -o $out dtb.tmp
     test -e $out
   '';
diff --git a/modules/base.nix b/modules/base.nix
index a142b88..b9964e9 100644
--- a/modules/base.nix
+++ b/modules/base.nix
@@ -75,6 +75,7 @@ in {
         default = [];
         example = ["ath9k" "ath10k"];
       };
+      rootDevice = mkOption { };
       networkInterfaces = mkOption {
         type = types.attrsOf types.anything;
       };
diff --git a/modules/flashable.nix b/modules/flashable.nix
new file mode 100644
index 0000000..8def6fc
--- /dev/null
+++ b/modules/flashable.nix
@@ -0,0 +1,71 @@
+{
+  config
+, pkgs
+, lib
+, ...
+}:
+let
+  inherit (lib) mkOption types concatStringsSep;
+  inherit (config.boot) tftp;
+in {
+  options = {
+    device.flash = {
+      address = mkOption { type = types.str; };
+      size = mkOption { type = types.str; };
+    };
+  };
+  config = {
+    kernel = {
+      config = {
+        MTD_SPLIT_UIMAGE_FW = "y";
+        # ignore the commandline provided by U-Boot because it's most
+        # likely wrong
+        MIPS_CMDLINE_FROM_BOOTLOADER = lib.mkForce "n";
+        MIPS_CMDLINE_FROM_DTB = "y";
+      };
+    };
+
+    boot.commandLine = [
+      "root=${config.device.rootDevice}"
+    ];
+    outputs.firmware =
+      let o = config.outputs; in
+      pkgs.runCommand "firmware" {} ''
+        dd if=${o.uimage} of=$out bs=128k conv=sync
+        dd if=${o.squashfs} of=$out bs=128k conv=sync,nocreat,notrunc oflag=append
+      '';
+    outputs.flashable =
+      let o = config.outputs; in
+      pkgs.runCommand "flashable" {} ''
+        mkdir $out
+        cd $out
+        ln -s ${o.firmware} firmware.bin
+        ln -s ${o.squashfs} squashfs
+        ln -s ${o.kernel} vmlinux
+        ln -s ${o.manifest} manifest
+        ln -s ${o.kernel.headers} build
+        ln -s ${o.uimage} uimage
+        ln -s ${o.dtb} dtb
+        ln -s ${o.flash-scr} flash.scr
+     '';
+
+    outputs.flash-scr =
+      let
+        inherit (pkgs.lib.trivial) toHexString;
+        inherit (pkgs.lib.lists) concatStringsSep;
+        inherit (config.device) flash;
+      in
+        pkgs.buildPackages.runCommand "" {} ''
+          imageSize=$(stat -L -c %s ${config.outputs.firmware})
+          cat > $out << EOF
+          setenv serverip ${tftp.serverip}
+          setenv ipaddr ${tftp.ipaddr}
+          tftp 0x$(printf %x ${tftp.loadAddress}) result/firmware.bin
+          erase 0x$(printf %x ${flash.address}) +0x$(printf %x ${flash.size})
+          cp.b 0x$(printf %x ${tftp.loadAddress}) 0x$(printf %x ${flash.address}) \''${filesize}
+          echo command line was ${builtins.toJSON (concatStringsSep " " config.boot.commandLine)}
+          EOF
+        '';
+
+  };
+}
diff --git a/modules/outputs.nix b/modules/outputs.nix
index 18e80e2..c72c9b5 100644
--- a/modules/outputs.nix
+++ b/modules/outputs.nix
@@ -23,6 +23,7 @@ in
         inherit (config.kernel) config src extraPatchPhase;
       };
       dtb =  (callPackage ../kernel/dtb.nix {}) {
+        inherit (config.boot) commandLine;
         dts = config.boot.dts.src;
         includes = config.boot.dts.includes ++ [
           "${kernel.headers}/include"
diff --git a/modules/tftpboot.nix b/modules/tftpboot.nix
index 7bd6b2f..d8e1ca2 100644
--- a/modules/tftpboot.nix
+++ b/modules/tftpboot.nix
@@ -26,6 +26,7 @@ in {
         MTD = "y";
         MTD_PHRAM = "y";
         MTD_CMDLINE_PARTS = "y";
+        MIPS_CMDLINE_FROM_BOOTLOADER = "y";
 
         # one or more of the following is required to get from
         # VFS: Cannot open root device "1f00" or unknown-block(31,0): error -6
diff --git a/rotuer.nix b/rotuer.nix
index 17ddd47..1d74bbd 100644
--- a/rotuer.nix
+++ b/rotuer.nix
@@ -44,6 +44,7 @@ in rec {
   imports = [
     ./modules/wlan.nix
     ./modules/tftpboot.nix
+    ./modules/flashable.nix
   ];
 
   kernel = {