GRUB device names wrt. ieee1275

[David Miller]

One issue I need to resolve before I can send finalized
patches out for sparc is about device naming.

Currently the PowerPC ieee1275 support allows using both device
aliases and full openfirmware device path names with the usual GRUB
partition specification concatenated at the end.  For the most part
this is fine.

This works for a large group of cases, but in general it will not
work.

The problem is two fold:

1) "," characters can appear anywhere in an openfirmware path
   name.  For example my workstations disk is:

        
/address@hidden,600000/address@hidden/address@hidden/address@hidden/address@hidden/address@hidden

   There are no quick workarounds for this.  For example, even if we
   can change the partition fetching code in GRUB to use "strrchr()"
   instead of "strchr()" in kern/disk.c:grub_disk_open() it will
   still think the above path has partition ",600000" or something
   silly like that.

2) Disks can have multiple comma seperated components especially
   on SCSI in OF path names.  For example a disk on target 2,
   lun 3, would have final path component "address@hidden,3"

   And currently that ",3" would look like a parition specification
   to GRUB.

Therefore, I would suggest that we adopt the openfirmware partition
specification of ":" on GRUB for ieee1275 platforms.

Then we just have a machine specific path seperator, defined in
some <grub/machine/foo.h> header file and the kernel/disk.c code
and elsewhere use the macro instead of ","

Any objections?