Re: [PATCH] QD65xx I/O ports

[Erik Mouw <erik@harddisk-recovery.com>]

On Fri, Apr 09, 2004 at 12:50:24AM +0200, Bartlomiej Zolnierkiewicz wrote:
> On Tuesday 06 of April 2004 13:31, Geert Uytterhoeven wrote:
> > I/O port numbers can be larger than 8-bit on many platforms (this caused a
> > warning when {out,in}b() cast reg to a pointer on platforms with memory
> > mapped I/O)
> 
> Was VESA Local Bus ever used on something else than 486?

IIRC there were early Pentium boards with VESA Local Bus (VLB), but my
memory is vague about that.

> I think it's better to just add "depends on X86" to drivers/ide/Kconfig.

VLB is nothing more than ISA with a 32 bit address and data bus. That
is exactly how many busses on embedded CPUs work, but with the
difference that they map the ISA 16bit memory and IO space somewhere in
their 4GB memory space.

For example: the Digital/Intel StrongARM SA-11x0 has a 32 bit bus,
which (with the help of some glue logic) works like a 32 bit ISA bus.
Quite some embedded hardware emulates a 16 bit ISA bus by mapping the
ISA memory and IO space in a special memory area which can live
anywhere in the 4GB space, and that's why Geert wants an unsigned long
address in {out,in}b().


Erik

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