ppc/pnv: Add a default formatted PNOR image

The default PNOR image is erased and not recognised by skiboot, so NVRAM
gets disabled. This change adds a tiny pnor file that is a proper FFS
image with a formatted NVRAM partition. This is recognised by skiboot and
will persist across machine reboots.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

pc-bios/README

@@ -43,6 +43,19 @@
   run an hypervisor OS or simply a host OS on the "baremetal"
   platform, also known as the PowerNV (Non-Virtualized) platform.
 
+- pnv-pnor.bin is a non-volatile RAM image used by PowerNV, which stores
+  NVRAM BIOS settings among other things. This image was created with the
+  following command (the ffspart tool can be found in the skiboot source tree):
+
+  ffspart -s 0x1000 -c 34 -i pnv-pnor.in -p pnv-pnor.bin
+
+  Where pnv-pnor.in contains the two lines (no leading whitespace):
+
+  NVRAM,0x01000,0x00020000,,,/dev/zero
+  VERSION,0x21000,0x00001000,,,/dev/zero
+
+  skiboot is then booted once to format the NVRAM partition.
+
 - QemuMacDrivers (https://github.com/ozbenh/QemuMacDrivers) is a project to
   provide virtualised drivers for PPC MacOS guests.
 

pc-bios/meson.build

@@ -70,6 +70,7 @@ blobs = [
   's390-ccw.img',
   'slof.bin',
   'skiboot.lid',
+  'pnv-pnor.bin',
   'palcode-clipper',
   'u-boot.e500',
   'u-boot-sam460-20100605.bin',