Re: [PATCH v11 03/11] firmware: xilinx: Add zynqmp IOCTL API for device control

[Michal Simek]

On 9.9.2018 03:18, Olof Johansson wrote:
> Hi,
> 
> On Fri, Aug 3, 2018 at 10:53 AM, Jolly Shah <jolly.shah@xxxxxxxxxx> wrote:
>> From: Rajan Vaja <rajanv@xxxxxxxxxx>
>>
>> Add ZynqMP firmware IOCTL API to control and configure
>> devices like PLLs, SD, Gem, etc.
>>
>> Signed-off-by: Rajan Vaja <rajanv@xxxxxxxxxx>
>> Signed-off-by: Jolly Shah <jollys@xxxxxxxxxx>
> 
> 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