Re: [PATCH v2 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts

From: Simon Horman <horms@verge.net.au>
To: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Magnus Damm <magnus.damm@gmail.com>,
	linux-renesas-soc@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 0/7] soc: renesas: rcar-gen3-sysc: Fix power request conflicts
Date: Sat, 31 Aug 2019 11:48:33 +0200	[thread overview]
Message-ID: <20190831094833.qhj6otyocnq2di5l@verge.net.au> (raw)
In-Reply-To: <20190828113618.6672-1-geert+renesas@glider.be>

On Wed, Aug 28, 2019 at 01:36:11PM +0200, Geert Uytterhoeven wrote:
> 	Hi all,
> 
> Recent R-Car Gen3 SoCs added an External Request Mask Register to the
> System Controller (SYSC).  This register allows to mask external power
> requests for CPU or 3DG domains, to prevent conflicts between powering
> off CPU cores or the 3D Graphics Engine, and changing the state of
> another power domain through SYSC, which could lead to CPG state machine
> lock-ups.
> 
> This patch series starts making use of this register.  Note that the
> register is optional, and that its location and contents are
> SoC-specific.
> 
> This was inspired by a patch in the BSP by Dien Pham
> <dien.pham.ry@renesas.com>.
> 
> Note that the issue fixed cannot happen in the upstream kernel, as
> upstream has no support for graphics acceleration yet.  SoCs lacking the
> External Request Mask Register may need a different mitigation in the
> future.
> 
> Changes compared to v1[1]:
>   - Improve description of cover letter and first patch.
> 
> Changes compared to RFC[2]:
>   - Rebased.
> 
> This has been boot-tested on R-Car H3 ES1.0, H3 ES2.0, M3-W ES1.0, M3-N,
> V3M, and E3 (only the last 3 have this register!), and regression-tested
> on R-Car Gen2.
> 
> This has not been tested on R-Car H3 ES3.0, M3-W ES2.0, and V3H.
> 
> For your convenience, this series is available in the
> topic/rcar3-sysc-extmask-v2 branch of my renesas-drivers git repository at
> git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git.
> 
> Thanks for your comments!

Looks good to me.

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>