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Message-ID: <alpine.LRH.2.00.0902261752310.29190@vixen.sonytel.be>
Date: Thu, 26 Feb 2009 17:53:56 +0100 (CET)
From: Geert Uytterhoeven <Geert.Uytterhoeven@...ycom.com>
To: Arnd Bergmann <arnd@...db.de>
cc: Ira Snyder <iws@...o.caltech.edu>, linuxppc-dev@...abs.org,
netdev@...r.kernel.org, Rusty Russell <rusty@...tcorp.com.au>,
linux-kernel@...r.kernel.org,
Jan-Bernd Themann <THEMANN@...ibm.com>
Subject: Re: [RFC v2] virtio: add virtio-over-PCI driver
On Thu, 26 Feb 2009, Arnd Bergmann wrote:
> On Tuesday 24 February 2009, Ira Snyder wrote:
> > +/* Virtio-over-PCI descriptors: 12 bytes. These can chain together via "next" */
> > +struct vop_desc {
> > + /* Address (host physical) */
> > + __le32 addr;
^^^^
Only 32-bit? Is this future-proof?
> > + /* Length (bytes) */
> > + __le32 len;
> > + /* Flags */
> > + __le16 flags;
> > + /* Chaining for descriptors */
> > + __le16 next;
> > +} __attribute__((packed));
>
> I would drop the "packed" attribute in the structure definitions.
> It would imply that only byte accesses are allowed on these
> data structures, because the attribute invalidates any assumptions
> about alignment. None of your structures require padding, so
> the attribute does not have any positive effect either.
>
> > +/* MPC8349EMDS specific get_immrbase() */
> > +#include <sysdev/fsl_soc.h>
>
> Do you really need get_immrbase? I would expect that you can find
> all the registers you need in the device tree, or exported from
> other low-level drivers per subsystem.
>
> immrbase is a concept from the time before our device trees.
>
> > +/*
> > + * These are internal use only versions of the structures that
> > + * are exported over PCI by this driver
> > + *
> > + * They are used internally to keep track of the PowerPC queues so that
> > + * we don't have to keep flipping endianness all the time
> > + */
> > +struct vop_loc_desc {
> > + u32 addr;
^^^
Same here.
With kind regards,
Geert Uytterhoeven
Software Architect
Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium
Phone: +32 (0)2 700 8453
Fax: +32 (0)2 700 8622
E-mail: Geert.Uytterhoeven@...ycom.com
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