From: David Miller <davem@davemloft.net>
To: mkl@pengutronix.de
Cc: kurt.van.dijck@eia.be, socketcan-core@lists.berlios.de,
netdev@vger.kernel.org
Subject: Re: [PATCH net-next-2.6 1/2] can: add driver for Softing card
Date: Tue, 04 Jan 2011 09:31:00 -0800 (PST) [thread overview]
Message-ID: <20110104.093100.71129805.davem@davemloft.net> (raw)
In-Reply-To: <4D22FC72.7040706@pengutronix.de>
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Tue, 04 Jan 2011 11:54:42 +0100
> There's ioread() and get_unaligned(). Do we have a combination of this?
No. And there will never be.
Because it's never well defined whether it is safe to break up an
I/O operation into two sub-operations, nor in what order those
sub-operations can be done in.
For example, just reading one byte of a two-byte register might
clear the status bits in other byte if the two bytes are read in
the wrong order.
On some chips, avoiding losing information might be completely
impossible.
You have to do it by hand in your driver, because only you know
what implementation will work correctly.
next prev parent reply other threads:[~2011-01-04 17:30 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-23 9:36 [PATCH net-next-2.6 0/2] can: add driver for Softing card Kurt Van Dijck
[not found] ` <20101223093627.GA325-MxZ6Iy/zr/UdbCeoMzGj59i2O/JbrIOy@public.gmane.org>
2010-12-23 9:43 ` [PATCH net-next-2.6 1/2] " Kurt Van Dijck
[not found] ` <20101223094302.GB325-MxZ6Iy/zr/UdbCeoMzGj59i2O/JbrIOy@public.gmane.org>
2010-12-23 14:25 ` Marc Kleine-Budde
2010-12-23 20:33 ` Oliver Hartkopp
[not found] ` <4D135BC3.6070707-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2010-12-24 9:14 ` Kurt Van Dijck
[not found] ` <20101224091428.GA375-MxZ6Iy/zr/UdbCeoMzGj59i2O/JbrIOy@public.gmane.org>
2010-12-24 11:44 ` Marc Kleine-Budde
[not found] ` <4D148788.3010808-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>
2011-01-03 16:38 ` Kurt Van Dijck
[not found] ` <20110103163835.GD320-MxZ6Iy/zr/UdbCeoMzGj59i2O/JbrIOy@public.gmane.org>
2011-01-03 17:33 ` David Miller
[not found] ` <20110103.093327.104057155.davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
2011-01-04 10:54 ` Marc Kleine-Budde
2011-01-04 17:31 ` David Miller [this message]
2011-01-04 12:19 ` Kurt Van Dijck
2011-01-04 12:25 ` Marc Kleine-Budde
2011-01-03 16:28 ` Kurt Van Dijck
2010-12-23 9:47 ` [PATCH net-next-2.6 2/2] " Kurt Van Dijck
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