| |
|
 |
|
 |
|
|
|
| |
|
|
xen-ppc-devel
Re: [XenPPC] [rfc] Serial discovery.
I was hoping to bring in and use as much as possible linux' pmac_zilog.h
that defines read and write regs inlined functions that only use readb
and writeb.
As for the NS driver I would wish for something a bit more robust that
testing the value of io_base. My changes to the serial code discovery
atm simply set io_base to be the sum of the value we squirrel in
isa_io_base and the device address. This would cause the ns device
driver on ppc to do always read/writeb. Not that is matters on ppc
becuase inb and outb in fact add the two anyway.
In general I would prefer to see logic in the serial discovery code that
decides if the device is on the isa bus, sets or checks isa_io_base, and
flags the device as one that should use inb/outb, rather than this funky
thing based on the value of io_base.
Jimi Xenidis wrote:
On May 4, 2006, at 7:54 AM, Maria Butrico wrote:
The ns device driver is shared between ia and ppc (and who knows what
else). What concerns me more is the way in which inb/outb is
selected and furthermore the fact that up to now on ppc we have been
using the emulated inb/outb and with my changes we would start using
readb/writeb exclusively.
The NS driver assumes that if the io_base > 0x10000 (the 16-bit limit
of ISA) then it must be an absolute address, and therefor has to be
ioremap()ed and accessed with the read*() interfaces that use absolute
addressing.
Not sure if we'll ever see a Zilog off an ISA, we certainly could.
It is way more likely that we'll all see an NS not on ISA :).
Hollis objects to removing the inb/outb, I don't feel as strongly so I
guess we can keep it.
Do I hear consensus on doing away with inb/outb for zilog?
I'd simply keep zilog ioremap()ed, readb()/writeb() and the first
person who sees it on an ISA can add that logic, but feel free to
repeat the NS logic if you wish.
-JX
_______________________________________________
Xen-ppc-devel mailing list
Xen-ppc-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ppc-devel
|
|
|
| |
|
Home