dear diary

THOUGHTS.txt

@@ -306,3 +306,38 @@ So
 
 Note regarding that second bullet: at the moment the static address
 service has no outputs anyway!
+
+
+Tue Oct  4 22:43:02 BST 2022
+
+While trying to make the TFTP workflow not awful I seem to have written
+a TFTP server.
+
+
+Thu Oct  6 19:26:40 BST 2022
+
+We have a booting kernel on gl-ar750, but we aren't at a point that it can
+find a root filesystem
+
+I'd *like* to be able to use the same delivery mechanism (kernel uimage
+concatenated monolithic
+
+
+Sat Oct  8 11:12:09 BST 2022
+
+We have it booting on hardware, mounting root fs, running getty :-)
+
+For NixWRT TFTP boots we used a single image with both kernel and squashfs, and
+relied on CONFIG_MTD_SPLIT_FIRMWARE to identify where the boundary was and create
+/dev/mdtn devices at the right offsets so that the kernel could find the
+squashfs
+
+For Liminix we're not going to do that.
+
+* CONFIG_MTD_SPLIT_FIRMWARE is only available in OpenWrt patches
+* it's an uncomfortable level of automagic just to save us doing two TFTPs
+  instea of one
+* the generated image is anyway not the one we'd write to flash (has unneeded
+   PHRAM support)
+* it means we need to memmap out enough ram for the whole image inc kernel when really
+  all we need to reserve is the rootfs bit

devices/gl-ar750.nix

@@ -23,17 +23,19 @@
   kernel = rec {
     checkedConfig = {
       "MIPS_ELF_APPENDED_DTB" = "y";
-      # possibly not all of these are needed, I just
-      # copied them from qemu
-      HW_CONSOLE = "y";
-      VT_HW_CONSOLE_BINDING = "y";
+      OF = "y";
+      USE_OF = "y";
       SERIAL_8250_CONSOLE = "y";
       SERIAL_8250 = "y";
       SERIAL_CORE_CONSOLE = "y";
-      DUMMY_CONSOLE = "y";
-      DUMMY_CONSOLE_COLUMNS = "80";
-      DUMMY_CONSOLE_ROWS = "25";
-      # FRAMEBUFFER_CONSOLE = "y";
+
+      # need this to open console device at boot. dmesg goes from
+      # [    0.272934] Warning: unable to open an initial console.
+      # to
+      # [    0.247413] printk: console [ttyS0] disabled
+      # [     0.25200] 18020000.uart: ttyS0 at MMIO 0x1802000 (irq = 10, base_baud = 1562500) is a 16550A
+      SERIAL_OF_PLATFORM = "y";
+
       CONSOLE_LOGLEVEL_DEFAULT = "8";
       CONSOLE_LOGLEVEL_QUIET = "4";
 
@@ -45,7 +47,7 @@
       # be present already
       BLK_DEV_INITRD = "n";
     };
-    config = checkedConfig // {
+    config = {
       CPU_LITTLE_ENDIAN= "n";
       CPU_BIG_ENDIAN= "y";
       ATH79 = "y";
@@ -65,11 +67,8 @@
       # at boot time unless we disable trying to call it
       "FW_LOADER_USER_HELPER" = "n";
 
-      # "IMAGE_CMDLINE_HACK" = "n";
-
       "MODULE_SIG" = "y";
       "MTD_CMDLINE_PARTS" = "y";
-#      "MTD_SPLIT_FIRMWARE" = "y";
       "PARTITION_ADVANCED" = "y";
       "PRINTK_TIME" = "y";
       "SQUASHFS" = "y";

modules/base.nix

@@ -55,6 +55,10 @@ in {
         PROC_FS = "y";
         # s6-linux-init mounts this on /dev
         DEVTMPFS = "y";
+        # some or all of these may be fix for "tmpfs: Unknown parameter 'mode'" error
+        TMPFS = "y";
+        TMPFS_POSIX_ACL = "y";
+        TMPFS_XATTR = "y";
       };
       checkedConfig = config;
     };

modules/s6/default.nix

@@ -73,7 +73,7 @@ let
       run = {
         file = ''
               #!${execline}/bin/execlineb -P
-              ${busybox}/bin/getty -l ${busybox}/bin/login 38400 /dev/console
+              ${busybox}/bin/getty -l ${busybox}/bin/login 115200 /dev/console
           '';
         mode = "0755";
       };