Re: new ata_port_operations for .pmp_{read,write} ?

[Mark Lord <liml@rtr.ca>]

Tejun Heo wrote:
> Hello, Mark.
> 
> Mark Lord wrote:
>> Mark Lord wrote:
>>> An alternative to all this, might be to expose the "select_pmp()"
>>> function shown in the sample code, and have libata-pmp.c call that,
>>> instead of having the new new .pmp_{read,write} functions. 
>> ..
>>
>> I wonder if this might be more viable than first thought.
>>
>> Say the LLD, be it ata_piix or sata_mv or sata_svw, were to provide
>> an option ata_operations method for "select_pmp_port(pmp)",
>> which the core could invoke prior to any direct manipulation
>> of the shadow registers.
> 
> I don't really think that's a good solution.  That's the quickest
> solution for sata_mv but it just works around more fundamental problem
> of assuming SFF behavior in core layer which we need to drop anyway.
> 
>> I really would like to keep the LLD code small, and have good solid
>> core routines for non-hardware specific functionality.  All of this stuff
>> I'm beginning to do with sata_mv would be trivial if I wanted to bloat
>> the LLD, but really.. only a tiny bit of it need be custom to sata_mv.
>>
>> The existing SFF reset/probe/pmp stuff is just about exactly what
>> sata_mv needs.. and I feel a strong desire to not clone/duplicate
>> that hard-won functionality.
> 
> I strongly agree but am having difficult time agreeing with the proposed
> approach.
..

Okay, then.  MASSIVE code-duplication, here I come!

-ml