Add serial-and-milk guide

diff --git a/serial/serial-and-milk.txt b/serial/serial-and-milk.txt
new file mode 100644 (file)
index 0000000..1530938
--- /dev/null
+++ b/serial/serial-and-milk.txt
@@ -0,0 +1,73 @@
+# Patching coreboot+SeaBIOS+PXE+Linux for input over serial
+
+Instructions here are specifically tailored to the KGPE-D16, but should work
+for other boards with minor modifications, particularly to the PCI ID of the
+Ethernet controller used when building and installing iPXE.
+
+----
+
+Get the base ROM (no need to recompile most of it, but you can if you want). Consider making a backup.
+
+       # flashrom -p internal -r coreboot.rom
+
+Enable the VGA<->serial console, sercon, in SeaBIOS. 1016 is the decimal
+encoding of `0x3f8`, the port number for serial on traditional PC
+architectures. 
+
+       # ./cbfstool coreboot.rom add-int -i 1016 -n etc/sercon-port
+
+Deduplicate duplicated character duplicates.
+
+       # ./cbfstool coreboot.rom add-int -i 0 -n etc/screen-and-debug
+
+----
+
+Get IPXE source code:
+
+       $ git clone git://git.ipxe.org/ipxe.git
+
+Patching IPXE to output purely over serial, bypassing weird VGA emulation, as per https://pelican.craoc.fr/coreboot.html#ipxe
+
+       diff --git a/src/config/console.h b/src/config/console.h
+       index 9f770d09..1f181177 100644
+       --- a/src/config/console.h
+       +++ b/src/config/console.h
+       @@ -22,9 +22,9 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+         *
+         */
+        
+       -//#undef       CONSOLE_PCBIOS          /* Default BIOS console */
+       -//#undef       CONSOLE_EFI             /* Default EFI console */
+       -//#undef       CONSOLE_LINUX           /* Default Linux console */
+       +#undef CONSOLE_PCBIOS          /* Default BIOS console */
+       +#undef CONSOLE_EFI             /* Default EFI console */
+       +#undef CONSOLE_LINUX           /* Default Linux console */
+        
+        /*
+         * Additional console types
+       @@ -34,7 +34,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+         *
+         */
+        
+       -//#define      CONSOLE_SERIAL          /* Serial port console */
+       +#define        CONSOLE_SERIAL          /* Serial port console */
+        //#define      CONSOLE_FRAMEBUFFER     /* Graphical framebuffer console */
+        //#define      CONSOLE_SYSLOG          /* Syslog console */
+        //#define      CONSOLE_SYSLOGS         /* Encrypted syslog console */
+
+Build IPXE:
+
+       $ make bin/808610d3.rom
+
+------------------
+
+Remove the existing IPXE rom and replace it with our patched one, 808610d3.rom. Name/build target corresponds to the vendor/device ID in PCI
+
+       # cbfstool coreboot.rom remove -n pci8086,10d3.rom                    
+       # cbfstool coreboot.rom add -f bin/808610d3.rom -n pci8086,10d3.rom -t raw
+
+------------------
+
+Flash it back:
+
+       # flashrom -p internal -w coreboot.rom