[PATCH v2 00/15] PCI io.h clean-up
Rob Herring
robherring2 at gmail.com
Mon Jul 16 10:03:15 EDT 2012
On 07/16/2012 02:52 AM, Andrew Lunn wrote:
> On Fri, Jul 13, 2012 at 09:03:56PM -0500, Rob Herring wrote:
>> From: Rob Herring <rob.herring at calxeda.com>
>>
>> This is the 2nd part of mach/io.h removals. This series removes io.h on
>> platforms with PCI by creating a fixed virtual I/O mapping and a common
>> __io() macro.
>
> Hi Rob
>
> Time to show my ignorance of PCI again.
>
> root at orion5x:~# cat /proc/ioports
> 00001000-0000ffff : PCI0 I/O
> 00010000-0001ffff : PCI1 I/O
>
> The changes you made for Orion decreased the window to 64K. However, i
> see here that PCI0 only gets 60K, where as PCI1 gets the full 64K.
>
> Is this asymmetry correct?
First, thanks for testing.
PC's only have 64K, so that should be enough for any platform. 0-0x1000
is reserved for legacy ISA range. Even if we set the start to 0,
pcibios_min_io would still limit it to above 0x1000.
Also, based on the address translation masking on these platforms, I
believe it should be okay to start the PCI bus address on a 64K boundary.
Rob
>
> I see this for both orion5x and kirkwood.
>
> Thanks
> Andrew
>
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