Re: [PATCH 1/5] dt-bindings: arm: coresight: Limit static replicator to atclk

[Leo Yan]

On Tue, Oct 13, 2026 at 07:53:20AM +0200, Michal Simek wrote:
> 
> 
> On 10/12/26 18:28, Leo Yan wrote:
> > On Mon, Oct 12, 2026 at 02:35:37PM +0200, Michal Simek wrote:
> > > 
> > > 
> > > On 10/2/26 17:07, Leo Yan wrote:
> > > > Static replicators have no programmable registers and need no APB
> > > > programming clock.
> > > > 
> > > > The Zynq clock controller registers dbg_trc and dbg_apb and calls
> > > > clk_prepare_enable() for each gate the bootloader left on.
> > > 
> > > That's one bootloader behavior. If there is another bootloader that clocks
> > > can be simply disabled. I don't think there is any reason to depends on
> > > bootloader behavior. If there are clocks which has to be ON I can't see any
> > > reason not to drive them.
> > 
> > My reference to zynq_clk_setup() was to explain that this patch leaves
> > the existing management of dbg_trc and dbg_apb unchanged.
> > 
> > The CoreSight drivers do not request clocks named "dbg_trc" or "dbg_apb".
> 
> And this is the point. DT binding is not describing what Linux driver handles.
> Binding describes HW itself.

I agreed that "Binding describes HW itself".

The question is which hardware clock connections the DT properties
describe. Arm DDI 0314H, Table B-1 [1], lists ATCLK for the replicator,
and ATCLK and PCLKDBG for the trace funnel. The static modules have no
APB programming interface.

> And for proper functionality these 2 clocks need to be handled.

Please point to the Zynq TRM section or clock diagram showing how
dbg_trc and dbg_apb supply the replicator and funnel.

> That Linux driver is not doing it that's different issue.

My understanding is the CoreSight drivers have already followed spec to
support clocks.

[1] https://support.arm.com/documentation/ddi0314/h/CoreSight-Components-and-Clock-Domains/CoreSight-components-and-clock-domains