Re: isa_read/write not available on ppc - solution suggestions ??

From: Linus Torvalds (torvalds@transmeta.com)
Date: Tue May 01 2001 - 12:22:39 EST


In article <OF7A9C6B22.E1638E60-ON85256A3F.004EADC7@urscorp.com>,
 <mike_phillips@urscorp.com> wrote:
>>mike_phillips@urscorp.com wrote:
>>>
>>> To get the pcmcia ibmtr driver (ibmtr/ibmtr_cs) working on ppc, all the
>>> isa_read/write's have to be changed to regular read/write due to the
>lack
>>> of the isa_read/write functions for ppc.
>
>> Treat it like a PCI device and use ioremap(). Then change isa_readl()
>> to readl() etc.
>
>Bleurgh, the latest version of the driver (not in the kernel yet) searches
>for turbo based cards by checking the isa address space from 0xc0000 -
>0xe0000 in 8k chunks. So we'd have to ioremap each 8k section, check it,
>find out the adapter isn't there and then iounmap it.
>
>Oh well, if that's what it takes =:0

I would suggest the opposite approach instead: make the PPC just support
isa_readx/isa_writex instead.

Much simpler, and doesn't need changes to (correct) driver sources.

I bet that the patch will be smaller too. It's a simple case of
 - do the ioremap() _once_ at bootup, save the result in a static
   variable somewhere.
 - implement the (one-liner) isa_readx/isa_writex functions.

On many architectures you don't even need to do the ioremap, as it's
always available (same as on x86).

                Linus
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