Re: [PATCH 3/3] bus: ti-sysc: Implement display subsystem reset quirk

[Tomi Valkeinen]

On 03/03/2020 17:13, Tony Lindgren wrote:
> Hi,
>
> * Tomi Valkeinen <tomi.valkeinen@xxxxxx> [200303 06:03]:
> > On 24/02/2020 21:12, Tony Lindgren wrote:
> > > +	/* Remap the whole module range to be able to reset dispc outputs */
> > > +	devm_iounmap(ddata->dev, ddata->module_va);
> > > +	ddata->module_va = devm_ioremap(ddata->dev,
> > > +					ddata->module_pa,
> > > +					ddata->module_size);
> >
> > Why is this needed? The range is not mapped when sysc_pre_reset_quirk_dss()
> > is called? This will unmap and remap twice, as this function is called
> > twice. And then left mapped.
>
> That's because by default we only ioremap the module revision, sysconfig
> and sysstatus register are and provide the rest as a range for the child
> nodes.
>
> In the dss quirk case we need to tinker with registers also in the dispc
> range, and at the parent dss probe time dispc has not probed yet.
>
> We may be able to eventually move the reset quirk to dispc, but then
> it won't happen in the current setup until after dss top level driver
> has loaded.
>
> We leave the module range ioremapped as we still need to access
> sysconfig related registers for PM runtime.

Ok, makes sense. I guess a minor improvement would be to unmap & remap once in 
sysc_pre_reset_quirk_dss before calling sysc_quirk_dispc.

 Tomi

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