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

[Leo Yan <leo.yan@arm.com>]

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 removing those unused clock properties introduces no additional
dependence on the bootloader. Could you clarify how retaining these
entries addresses the bootloader concern?

> TRM page 741
> 
> Trace Port Clock The trace port clock is used to clock the TPIU and trace
> buffer when the MIO interface is chosen and must be twice the frequency of
> the desired TPIU clock. The TPIU clock frequency must be chosen to be fast
> enough to allow the trace port to keep up with the amount of data being
> traced, but slow enough to meet the dynamic characteristics of the data
> output buffers of the TPIU.

The quoted paragraph establishes a trace-clock requirement for the TPIU
and trace buffer, how does it identify the clock inputs of the funnel
and replicator?

Thanks,
Leo