liminix/modules/phram.nix

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{
config
, pkgs
, lib
, ...
}:
let
inherit (lib) mkOption types concatStringsSep;
cfg = config.boot.tftp;
in {
options = {
boot = {
tftp = {
loadAddress = mkOption { type = types.str; };
# These names match the uboot environment variables. I reserve
# the right to change them if I think of better ones.
ipaddr = mkOption { type = types.str; };
serverip = mkOption { type = types.str; };
};
};
};
config = {
kernel = {
config = {
MTD = "y";
MTD_PHRAM = "y";
MTD_CMDLINE_PARTS = "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
# to
# VFS: Mounted root (squashfs filesystem) readonly on device 31:0.
MTD_OF_PARTS = "y";
PARTITION_ADVANCED = "y";
MSDOS_PARTITION = "y";
EFI_PARTITION = "y";
MTD_BLKDEVS = "y";
MTD_BLOCK = "y";
# CONFIG_MTD_MTDRAM=m c'est quoi?
};
};
outputs.tftproot =
let o = config.outputs; in
pkgs.runCommand "tftproot" {} ''
mkdir $out
cd $out
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 ${o.boot-scr} flash.scr
'';
outputs.boot-scr =
let
inherit (pkgs.lib.trivial) toHexString;
in
pkgs.buildPackages.runCommand "" {} ''
uimageSize=$(($(stat -L -c %s ${config.outputs.uimage}) + 0x1000 &(~0xfff)))
squashfsStart=0x$(printf %x $((${cfg.loadAddress} + $uimageSize)))
squashfsBytes=$(($(stat -L -c %s ${config.outputs.squashfs}) + 0x100000 &(~0xfffff)))
squashfsMb=$(($squashfsBytes >> 20))
cmd="mtdparts=phram0:''${squashfsMb}M(nix) phram.phram=phram0,''${squashfsStart},''${squashfsMb}Mi memmap=''${squashfsMb}M\$''${squashfsStart} root=1f00";
cat > $out << EOF
setenv serverip ${cfg.serverip}
setenv ipaddr ${cfg.ipaddr}
setenv bootargs '${concatStringsSep " " config.boot.commandLine} $cmd'
tftp 0x$(printf %x ${cfg.loadAddress}) result/uimage ; tftp 0x$(printf %x $squashfsStart) result/squashfs
bootm 0x$(printf %x ${cfg.loadAddress})
EOF
'';
};
}