From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gerd Hoffmann <kraxel@redhat.com>
Subject: Re: [PATCH v2] QEMU fw_cfg DMA interface documentation
Date: Mon, 07 Sep 2015 13:08:29 +0200
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Cc: Stefan Hajnoczi <stefanha@gmail.com>, linux-kernel <linux-kernel@vger.kernel.org>, Drew <drjones@redhat.com>, Kevin O'Connor <kevin@koconnor.net>, Laszlo <lersek@redhat.com>, Arnd Bergmann <arnd@arndb.de>, Rob Herring <rob.herring@linaro.org>, Mark Rutland <mark.rutland@arm.com>, Alexander Graf <agraf@suse.de>, devicetree@vger.kernel.org
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  Hi,

> It's just simplicity. If you want to read a few times from the same
> field (like in ACPI tables, read the data size and then the data), you
> need a way to enable and disable the selector and manage the current
> offset for that entry. This is already provided with the "old"
> interface.

Could be handled with a 'select' control bit.  Only when set select
entry and reset offset to zero.

Also: would it make sense to allow an *array* of FWCfgDmaAccess structs?
With a 'more' bit in control we could indicate that there are more
entries.  I'm not sure firmware would actually use that though ...

cheers,
  Gerd