Reads device informations / configuration from json file.

This allows many more devices to be implicitly working, once
their kernel and device-specific quirks have been ported over.

README.md

@@ -10,7 +10,7 @@ WIP notes
 ---------
 
 ```
-nix-build bootimg.nix
+nix-build bootimg.nix --arg device_name '"asus-z00t"'
 # Maybe `nix copy ./result --to ssh://another-host`
 adb wait-for-device && adb reboot bootloader
 fastboot boot result # or full path

bootimg.nix

@@ -1,24 +1,19 @@
 {
-  device_name ? "asus-z00t"
+  device_name
 }:
 with (import ./overlay);
 
 let
-  # TODO : import this from device description
+  deviceinfo = (lib.importJSON ./devices/postmarketOS-devices.json).${device_name};
   linux = pkgs."linux_${device_name}";
   kernel = "${linux}/Image.gz-dtb";
   dt = "${linux}/boot/dt.img";
-  cmdline = "androidboot.hardware=qcom ehci-hcd.park=3 androidboot.bootdevice=7824900.sdhci lpm_levels.sleep_disabled=1 androidboot.selinux=permissive";
-  ramdisk = callPackage ./rootfs.nix { inherit device_name; };
-
-  base           = "0x10000000";
-  kernel_offset  = "0x00008000";
-  second_offset  = "0x00f00000";
-  ramdisk_offset = "0x02000000";
-  tags_offset    = "0x00000100";
-  pagesize       = "2048";
 
+  # TODO : Allow appending / prepending
+  cmdline = deviceinfo.kernel_cmdline;
 
+  # TODO : make configurable?
+  initrd = callPackage ./rootfs.nix { inherit device_name; };
 in
 stdenv.mkDerivation {
   name = "nixos-mobile_${device_name}_boot.img";
@@ -36,14 +31,14 @@ stdenv.mkDerivation {
     mkbootimg \
       --kernel  ${kernel} \
       --dt      ${dt} \
-      --ramdisk ${ramdisk} \
-      --cmdline "${cmdline}" \
-      --base           ${base          } \
-      --kernel_offset  ${kernel_offset } \
-      --second_offset  ${second_offset } \
-      --ramdisk_offset ${ramdisk_offset} \
-      --tags_offset    ${tags_offset   } \
-      --pagesize       ${pagesize      } \
+      --ramdisk ${initrd} \
+      --cmdline       "${cmdline}" \
+      --base           ${deviceinfo.flash_offset_base   } \
+      --kernel_offset  ${deviceinfo.flash_offset_kernel } \
+      --second_offset  ${deviceinfo.flash_offset_second } \
+      --ramdisk_offset ${deviceinfo.flash_offset_ramdisk} \
+      --tags_offset    ${deviceinfo.flash_offset_tags   } \
+      --pagesize       ${deviceinfo.flash_pagesize      } \
       -o $out
   '';
 }