Introduce multiple partitions support to disk_image

Rootfses that should be written to disk as their own partition are
called *_ROOTFS instead of *_RAMDISK.

This change makes the config file clearer and more consistent. However
it changes the current behavior as the Dom0 RAMDISK (not ROOTFS) was
written to disk as its own partition before, and now it is not.

In the case of uboot-script-gen, dom0less guests cannot access disk
partitions yet (missing PV drivers support). Hence, if one or more domU
ROOTFSes are specified, print an error and exit. For dom0, base the
root= parameter generation on the presence of DOM0_ROOTFS.

Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>
Signed-off-by: Brian Woods <brian.woods@xilinx.com>
Reviewed-by: Brian Woods <brian.woods@xilinx.com>

1 files changed, 14 insertions, 4 deletions

diff --git a/README.md b/README.md
index f7da514..eaa7431 100644
--- a/README.md
+++ b/README.md
@@ -106,10 +106,20 @@ Where:\
 
 ## scripts/disk\_image
 
-The ImageBuilder script that generates a disk image file to load on a
-SD or SATA drive.  This creates 2 partitions: boot partition where the
-boot files from working directory (-c option) are, and the dom0 ramdisk
-uncompressed into the root FS partition.
+The ImageBuilder script that generates a disk image file to load on a SD
+or SATA drive.  This creates multiple partitions: 1 boot partition where
+the boot files from working directory (-c option) are, and 1 additional
+partition for each Dom0/DomU cpio archive to write to disk.
+
+disk\_image will write to disk as separate partition each file specified
+as follows:
+
+- DOM0_ROOTFS specifies the Dom0 rootfs to use. Note that the file to
+  write should be a regular cpio.gz file, not a u-boot binary.
+
+- DOMU_ROOTFS[number] specifies the DomU rootfs to use. Note that it
+  should be a regular cpio.gz file, not a u-boot binary.
+
 
 After you've generated the u-boot scripts using the uboot-script-gen
 script, disk_image is run as follows: