Re: [PATCH 01/23] devicetree: bindings: hisi_sas: add v2 HW bindings

[John Garry]

> > > > +Optional main node properties:
> > > > + - am-max-trans : limit controller for am max transmissions
> > >
> > > Is this a boolean? Number?
> >
> > This is a boolean. It is for dealing with a quirk in the chipset: an
> > instance of the controller in the hip06 chipset requires registers
> > set with a different init value.
>
> Ok. I think the property at needs a better description for that.
>
> It's not clear to me how "limit controller for am max transmissions"
> maps to writing a specific value to some registers, but I don't know
> much about SAS.
>
> Is this some well-known thing, or values specific to hip06?
>
> Thanks,
> Mark.

This is a specific issue for hip06 chipset. There is a bug in the HW on 
hip06 where controller #1 has to set to 2 registers to non-default 
values to limit "am-max-transmissions". This would not be a common 
SAS/SCSI controller property and is specific to our HW.

Thanks,
John