Re: [RFC 7/8] fpga-region: add sysfs interface

From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Moritz Fischer <moritz.fischer@ettus.com>
Cc: "Nadathur, Sundar" <sundar.nadathur@intel.com>,
	Alan Tull <delicious.quinoa@gmail.com>,
	Yves Vandervennet <yves.vandervennet@linux.intel.com>,
	"matthew.gerlach@linux.intel.com"
	<matthew.gerlach@linux.intel.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	"linux-fpga@vger.kernel.org" <linux-fpga@vger.kernel.org>,
	Marek Va??ut <marex@denx.de>
Subject: Re: [RFC 7/8] fpga-region: add sysfs interface
Date: Wed, 22 Feb 2017 09:44:00 -0700	[thread overview]
Message-ID: <20170222164400.GA18745@obsidianresearch.com> (raw)
In-Reply-To: <CAAtXAHf0+DM+3uL5_dLxFZ_VmruYZzOpi5p0yu0jQwKniHA86A@mail.gmail.com>

On Tue, Feb 21, 2017 at 10:05:42PM -0800, Moritz Fischer wrote:

> That being said older drivers / fpga-mgr  will not deal with newer features.
> TLV / KV or whatever doesn't change this fact, or am I missing something?

Often a scheme will have an OPTIONAL and REQUIRED flag for each
value. If a REQUIRED value is present but the parser does not
support it then the parse fails.

For instance, we could mark Encrypted as required, and a zynq driver
that does not support the Encrypted tag would not load the bitfile
rather than try to load it wrongly.

This can be forced into any of the approaches with various levels of
hackery.

Jason