405GP TLBHI "E" field

405GP TLBHI "E" field

[Curry, Diane]

Hello,
  I'm running 2.4.14pre3 on a custom ppc405GP board that has a little-endian device
on the peripheral bus.  I've modified the finish_tlb_load code path to recognize the
physical address of the device and set the "E" bit in the tlb entry for the page.
The driver and device work fine using this feature, but what I did in finish_tlb_load
is not a reasonable solution.  Is there a kernel interface callable from a driver
that can be used to specify the endianness of a memory range, and set the "E"
bit appropriately?  If not, are there any plans to implement this capability?

Thanks, in advance.

Diane Curry


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Re: 405GP TLBHI "E" field

[Matt Porter]

On Tue, May 21, 2002 at 10:04:21AM -0400, Curry, Diane wrote:
>
> Hello,
>   I'm running 2.4.14pre3 on a custom ppc405GP board that has a little-endian device
> on the peripheral bus.  I've modified the finish_tlb_load code path to recognize the
> physical address of the device and set the "E" bit in the tlb entry for the page.
> The driver and device work fine using this feature, but what I did in finish_tlb_load
> is not a reasonable solution.  Is there a kernel interface callable from a driver
> that can be used to specify the endianness of a memory range, and set the "E"
> bit appropriately?  If not, are there any plans to implement this capability?

There are no plans (that I've ever heard of) to implement E bit support
because it has no value in Linux.  Use read*/write* to access your little
endian device.  PPC has lwbrx/stwbrx for a reason...use them...they are
included for free.

Regards,
--
Matt Porter
porter@cox.net

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