didn't need u-boot

THOUGHTS.txt

@@ -2436,3 +2436,17 @@ Sun Sep 17 16:44:31 BST 2023
 Can we figure out which bits of the old doc are missing from the new
 one and just transplant those? Then we can merge it sooner
 instead of blocking on writig all the new stuff
+
+We need to find a nice place for an introduction to choosing
+rootfsType
+
+Mon Sep 18 17:07:56 BST 2023
+
+Let's see if we can hack up an aarch64 qemu port
+
+From https://gist.github.com/oznu/ac9efae7c24fd1f37f1d933254587aa4 :
+
+curl -L https://releases.linaro.org/components/kernel/uefi-linaro/latest/release/qemu64/QEMU_EFI.fd -O
+dd if=/dev/zero of=flash1.img bs=1M count=64
+dd if=/dev/zero of=flash0.img bs=1M count=64
+dd if=QEMU_EFI.fd of=flash0.img conv=notrunc

devices/qemu-aarch64/default.nix

@@ -0,0 +1,75 @@
+# This "device" generates images that can be used with the QEMU
+# emulator. The default output is a directory containing separate
+# kernel (uncompressed vmlinux) and initrd (squashfs) images
+{
+  system = {
+    crossSystem = {
+      config = "aarch64-unknown-linux-musl";
+    };
+  };
+
+  module = {pkgs, config, ... }: {
+    kernel = {
+      src = pkgs.pkgsBuildBuild.fetchurl {
+        name = "linux.tar.gz";
+        url = "https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.15.71.tar.gz";
+        hash = "sha256-yhO2cXIeIgUxkSZf/4aAsF11uxyh+UUZu6D1h92vCD8=";
+      };
+      config = {
+        CPU_LITTLE_ENDIAN= "y";
+        CPU_BIG_ENDIAN= "n";
+
+        VIRTUALIZATION = "y";
+        PCI_HOST_GENERIC="y";
+
+        MTD = "y";
+        MTD_BLOCK2MTD = "y";
+        MTD_BLKDEVS = "y";
+        MTD_BLOCK = "y";
+
+        VIRTIO_MENU = "y";
+        PCI = "y";
+        VIRTIO_PCI = "y";
+        BLOCK = "y";
+        VIRTIO_BLK = "y";
+        NETDEVICES = "y";
+        VIRTIO_NET = "y";
+
+        # https://stackoverflow.com/a/68340492
+        CMDLINE="\"earlycon=smh console=ttyAMA0\"";
+        CMDLINE_FROM_BOOTLOADER = "y";
+
+        SERIAL_EARLYCON_ARM_SEMIHOST = "y"; # earlycon=smh
+        SERIAL_AMBA_PL011 = "y";
+        SERIAL_AMBA_PL011_CONSOLE = "y";
+      };
+    };
+    hardware =
+      let
+        mac80211 =  pkgs.mac80211.override {
+          drivers = ["mac80211_hwsim"];
+          klibBuild = config.system.outputs.kernel.modulesupport;
+        };
+      in {
+        defaultOutput = "vmroot";
+        loadAddress = "0x0";
+        entryPoint  = "0x0";
+        dts.src = ./empty.dts;
+        rootDevice = "/dev/mtd1";
+
+        flash.eraseBlockSize = "65536"; # c.f. pkgs/mips-vm/mips-vm.sh
+        networkInterfaces =
+          let inherit (config.system.service.network) link;
+          in {
+            wan = link.build { ifname = "eth0"; };
+            lan = link.build { ifname = "eth1"; };
+
+            wlan_24 = link.build {
+              ifname = "wlan0";
+              dependencies = [ mac80211 ];
+            };
+          };
+      };
+
+  };
+}

devices/qemu-aarch64/empty.dts

@@ -0,0 +1,3 @@
+/dts-v1/;
+
+/ { };

doc/admin.rst

@@ -120,13 +120,14 @@ hardware-specific, and sometimes involves soldering: please refer
 to the :ref:`development manual <tftp server>`.
 
 
-Flashing from OpenWrt (not currently advised!)
-==============================================
+Flashing from OpenWrt
+=====================
 
-.. CAUTION:: At your own risk! This will (at least in some
-             circumstances) lead to bricking the device: we think this
-             flash method is currently incompatible with use of a
-             writeable (jffs2) filesystem.
+.. CAUTION:: Untested! A previous version of these instructions
+	     (without the -e flag) led to bricking the device
+	     when flashing a jffs2 image. If you are reading
+	     this message, nobody has yet reported on whether the
+	     new instructions are any better.
 
 If your device is running OpenWrt then it probably has the
 :command:`mtd` command installed. After transferring the image onto the
@@ -134,7 +135,10 @@ device using e.g. :command:`ssh`,  you can run it as follows:
 
 .. code-block:: console
 
-   mtd -r write /tmp/firmware.bin firmware
+   mtd -e -r write /tmp/firmware.bin firmware
+
+The options to this command are for "erase before writing" and "reboot
+after writing". 
    
 For more information, please see the `OpenWrt manual <https://openwrt.org/docs/guide-user/installation/sysupgrade.cli>`_ which may also contain (hardware-dependent) instructions on how to flash an image using the vendor firmware - perhaps even from a web interface.
 

kernel/uimage.nix

@@ -6,6 +6,7 @@
 } :
 let
   objcopy = "${stdenv.cc.bintools.targetPrefix}objcopy";
+  arch = "arm64";
 in {
   kernel
 , commandLine
@@ -40,7 +41,7 @@ stdenv.mkDerivation {
   buildPhase = ''
     ${objcopy} -O binary -R .reginfo -R .notes -R .note -R .comment -R .mdebug -R .note.gnu.build-id -S vmlinux.elf vmlinux.bin
     rm -f vmlinux.bin.lzma ; lzma -k -z  vmlinux.bin
-    mkimage -A mips -O linux -T kernel -C lzma -a ${loadAddress} -e ${entryPoint} -n 'MIPS Liminix Linux ${extraName}' -d vmlinux.bin.lzma kernel.uimage
+    mkimage -A ${arch} -O linux -T kernel -C lzma -a ${loadAddress} -e ${entryPoint} -n '${arch} Liminix Linux ${extraName}' -d vmlinux.bin.lzma kernel.uimage
   '';
   installPhase = ''
     cp kernel.uimage $out

modules/kernel.nix

@@ -56,9 +56,9 @@ in {
         MODULE_SIG = if modular then "y" else "n";
         DEBUG_FS = "y";
 
-        MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE = "y";
-        MIPS_BOOTLOADER_CMDLINE_COOKIE = "\"liminix\"";
-        MIPS_CMDLINE_DTB_EXTEND = "y";
+        # MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE = "y";
+        # MIPS_BOOTLOADER_CMDLINE_COOKIE = "\"liminix\"";
+        # MIPS_CMDLINE_DTB_EXTEND = "y";
 
         # basic networking protocols
         NET = "y";

modules/outputs.nix

@@ -76,11 +76,12 @@ in
         inherit dtb;
       };
       # could use trivial-builders.linkFarmFromDrvs here?
-      vmroot = pkgs.runCommand "qemu" {} ''
+      vmroot = pkgs.runCommandCC "vmroot" {} ''
         mkdir $out
         cd $out
         ln -s ${config.system.outputs.rootfs} rootfs
         ln -s ${kernel} vmlinux
+        ${pkgs.stdenv.cc.targetPrefix}objcopy -O binary -S ${kernel} Image
         ln -s ${manifest} manifest
         ln -s ${kernel.headers} build
       '';

pkgs/kernel/default.nix

@@ -28,7 +28,7 @@ stdenv.mkDerivation rec {
     "-I${openssl.dev}/include -L${openssl.out}/lib -L${ncurses.out}/lib";
   PKG_CONFIG_PATH = "./pkgconfig";
   CROSS_COMPILE = stdenv.cc.bintools.targetPrefix;
-  ARCH = "mips";  # kernel uses "mips" here for both mips and mipsel
+  ARCH = "arm64";
   KBUILD_BUILD_HOST = "liminix.builder";
 
   dontStrip = true;
@@ -47,7 +47,7 @@ stdenv.mkDerivation rec {
   ];
 
   patches = [
-    ./cmdline-cookie.patch
+#    ./cmdline-cookie.patch
   ];
 
   # this is here to work around what I think is a bug in nixpkgs

pkgs/mips-vm/mips-vm.sh

@@ -42,10 +42,13 @@ fi
 
 INIT=${INIT-/bin/init}
 echo $QEMU_OPTIONS
-qemu-system-mips \
-    -M malta -m 256 \
+
+qemu-system-aarch64 \
+    -M virt  -m 512 \
     -echr 16 \
-    -append "liminix default console=ttyS0,38400n8 panic=10 oops=panic init=$INIT loglevel=8 root=/dev/mtdblock0 block2mtd.block2mtd=/dev/vda,65536" \
+    -append "liminix default earlycon=smh console=ttyAMA0,38400n8 panic=10 oops=panic init=$INIT loglevel=8 root=/dev/mtdblock0 block2mtd.block2mtd=/dev/vda,65536" \
+    -semihosting \
+    -cpu cortex-a72 \
     -drive file=$rootfs,format=raw,readonly=off,if=virtio,index=0 \
     ${initramfs} \
     -netdev socket,id=access,mcast=230.0.0.1:1234,localaddr=127.0.0.1 \

shell.nix

@@ -1,7 +1,7 @@
 let
   nixpkgs = <nixpkgs>;
   liminix = (import ./default.nix {
-    device = (import ./devices/qemu);
+    device = (import ./devices/qemu-aarch64);
     liminix-config = ./vanilla-configuration.nix;
     inherit nixpkgs;
   });