Re: Big Fix for 2.2.1

Linux Lists (lists@cyclades.com)
Wed, 27 Jan 1999 12:16:19 -0800 (PST)


On Wed, 27 Jan 1999, Linus Torvalds wrote:
>
> On Wed, 27 Jan 1999, MOLNAR Ingo wrote:
> >
> > the attached patch works for me, but i guess it's definitely too ugly to
> > live in the stock kernel. Anyway, if anyone wants to have non-power-2
> > -PAGE_OFFSET, this patch might help...
>
> It's definitely too ugly.
>
> What you can do, is just something silly like this at bootup:
>
> global void * isa_legacy_region;
>
>
> pci_setup() or whatever {
> isa_legacy_region = ioremap(0xA0000, 0x60000);
> }
>
> and then change everybody who uses "readX/writeX" to legacy addresses to
> do read_ISA_X/write_ISA_X and then have something like
>
> static inline unsigned char read_ISA_b(unsigned int legacy_address)
> {
> return readb(legacy_address+isa_legacy_region);
> }

Please don't do that. The Cyclades driver supports both ISA and PCI cards,
and it follows correctly the current definition, by ioremap'ing addresses
above 1MB and using readX/writeX for _all_ accesses to MMIO resources (in
ISA or PCI). Doing this change would mean having to test which card I'm
accessing _every time_ I do a readX/writeX, which is completelly
unacceptable (for obvious performance reasons).

Regards,
Ivan Passos

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