Re: [PATCH 2/6] dp8393x: don't force 32-bit register access

[Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>]

On 03/07/2021 17:29, Philippe Mathieu-Daudé wrote:

> On 7/3/21 4:39 PM, Mark Cave-Ayland wrote:
>> On 03/07/2021 15:19, Philippe Mathieu-Daudé wrote:
>>
>>> From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
>>>
>>> Commit 3fe9a838ec "dp8393x: Always use 32-bit accesses" assumed that
>>> all accesses
>>> to the registers were 32-bit but this is actually not the case. The
>>> access size is
>>> determined by the CPU instruction used and not the number of physical
>>> address lines.
>>>
>>> The big_endian workaround applied to the register read/writes was
>>> actually caused
>>> by forcing the access size to 32-bit when the guest OS was using a
>>> 16-bit access.
>>> Since the registers are 16-bit then we can simply set .impl.min_access
>>> to 2 and
>>> then the memory API will automatically do the right thing for both
>>> 16-bit accesses
>>> used by Linux and 32-bit accesses used by the MacOS toolbox ROM.
>>
>> The change should work, but the commit message above needs a slight
>> tweak - maybe something like this?
>>
>> Since the registers are 16-bit then we can simply set both
>> .impl.min_access and .impl.max_access to 2 and then the memory API will
>> automatically do the right thing for both 16-bit accesses used by Linux
>> and 32-bit accesses used by the MacOS toolbox ROM.
> 
> Do you mind sending v3 of this patch reworded (and including the .valid
> fields)?

I've sent a v3 with the rewording but dropping the .valid fields since that breaks 
MacOS and removed Finn's T-b tag as it may be there is an issue here with mips64el - 
whilst it works for me on all of my test images, I'm struggling to keep up with all 
the patches flying around everywhere :/

Now that your MIPS PR has been applied, perhaps it is worth sending a rebased v2 of 
your RFC "dp8393x: Housekeeping" patchset to ensure that everyone is up to date with 
the latest fixes? I won't be able to have a look at the CRC patchset for a few days 
though.


ATB,

Mark.