linux-kernel - Re: [PATCH 00/13] arm64: Allwinner A64 support based on sunxi-ng

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Date:	Mon, 1 Aug 2016 10:30:24 +0200
From:	Jean-Francois Moine <moinejf@...e.fr>
To:	André Przywara <andre.przywara@....com>
Cc:	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Rob Herring <robh+dt@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
	Mike Turquette <mturquette@...libre.com>,
	Stephen Boyd <sboyd@...eaurora.org>,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org
Subject: Re: [PATCH 00/13] arm64: Allwinner A64 support based on sunxi-ng

On Mon, 1 Aug 2016 02:43:06 +0100
André Przywara <andre.przywara@....com> wrote:

> As this became quite a long read, here a TL;DR:
> - We consider using an SCPI based clock system for the A64, alongside
> allwinner,simple-gates and fixed clocks. We try to avoid any Allwinner
> specific clocks (apart from the simple-gates).
> - ARM Trusted Firmware provides the SCPI implementation - for now, later
> we may move this into a possible arisc firmware.
> - We upstream some basic DT first, possibly omitting any controversial
> clock parts at all.
> 
> Let me know what you think!

Hi André,

This looks interesting.
As I understand, the clock enable/rate setting functions would be in
the arisc. The arisc firmware would be loaded only once in the Soc and
would contain the code for handling this specific SoC.
>From my calculations, this would save about 1Mb of clock descriptions
in the kernel for a universal Allwinner kernel.

But I don't see why you are keeping the simple-gates. The bus gate may
be ungated/gated when the clock is enabled/disabled, and that's what
Allwinner's software does.

-- 
Ken ar c'hentañ	|	      ** Breizh ha Linux atav! **
Jef		|		http://moinejf.free.fr/