Before this change, OFW initrd (as md) handling code was simulating an ofwbus
device. But as there isn't really a Device Tree (DT) node representing OFW
initrd (it is specified in 2 properties under /chosen), its driver was in fact
stealing other driver's DT node. This was noticed after MD_ROOT_MEM became
default and QEMU's USB keyboard stopped working under VNC.
This change consists in simplifying the process of detection and mapping of
initrd memory, turning it into a simple startup step, instead of trying to
simulate a device.
Reviewed by: jhibbits
Differential Revision: https://reviews.freebsd.org/D20553
This is an OFW initrd module that would load the initrd from device tree
parameters and give the to the md driver.
With this patch, it is possible to pass a rootfs image through kexec in PowerNV
mode (powerpc64). In order to user it, you should set the MD_ROOT_MEM option in
your kernel configuration.
Reviewed by: jhibbits
Approved by: jhibbits (mentor)
Differential Revision: https://reviews.freebsd.org/D15705
