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Subject: Re: [PATCH v11 03/11] firmware: xilinx: Add zynqmp IOCTL API for
 device control
To: Olof Johansson <olof@lixom.net>, Jolly Shah <jolly.shah@xilinx.com>
CC: "ard.biesheuvel@linaro.org" <ard.biesheuvel@linaro.org>, Ingo Molnar
	<mingo@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	<matt@codeblueprint.co.uk>, Sudeep Holla <sudeep.holla@arm.com>,
	<hkallweit1@gmail.com>, Kees Cook <keescook@chromium.org>, Dmitry Torokhov
	<dmitry.torokhov@gmail.com>, Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@codeaurora.org>, Michal Simek <michal.simek@xilinx.com>,
	Rob Herring <robh+dt@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
	linux-clk <linux-clk@vger.kernel.org>, <rajanv@xilinx.com>, Linux ARM Mailing
 List <linux-arm-kernel@lists.infradead.org>, Linux Kernel Mailing List
	<linux-kernel@vger.kernel.org>, DTML <devicetree@vger.kernel.org>, Jolly Shah
	<jollys@xilinx.com>
References: <1533318808-10781-1-git-send-email-jollys@xilinx.com>
 <1533318808-10781-4-git-send-email-jollys@xilinx.com>
 <CAOesGMi7Q9L4oZkUubKtV-m8XD67MQ05ZFhPA_0Hwky_qVUxfg@mail.gmail.com>
From: Michal Simek <michal.simek@xilinx.com>
Message-ID: <89a81241-e2c3-9fdf-7436-3d50025cec4d@xilinx.com>
Date: Mon, 10 Sep 2018 14:34:35 +0200
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On 9.9.2018 03:18, Olof Johansson wrote:
> Hi,
> 
> On Fri, Aug 3, 2018 at 10:53 AM, Jolly Shah <jolly.shah@xilinx.com> wrote:
>> From: Rajan Vaja <rajanv@xilinx.com>
>>
>> Add ZynqMP firmware IOCTL API to control and configure
>> devices like PLLs, SD, Gem, etc.
>>
>> Signed-off-by: Rajan Vaja <rajanv@xilinx.com>
>> Signed-off-by: Jolly Shah <jollys@xilinx.com>
> 
> This patch worries me somewhat. It's a transparent pass-through ioctl
> driver. Is there a spec available for what the implemented IOCTLs are?

https://www.xilinx.com/support/documentation/user_guides/ug1200-eemi-api.pdf

> 
> Should some of them be proper drivers instead of an opaque
> pass-through like this? Could some of them have stability impact on
> the platform such that there are security concerns and the list of
> arguments should somehow be sanitized?

You can look at for example reset driver which is using this eemi interface.
https://lkml.org/lkml/2018/9/5/144

> What's the intended usecase anyway? Just a debug tool during
> development, or something that you expect heavy use of by some
> userspace middleware?

I am not an author of this interface but there is no intention to enable
this interface for userspace as far as I see. All functions should be
used by kernel drivers only.

Jolly: Please answer all others concern in connection to this patchset.

Thanks,
Michal