From: u.kleine-koenig@pengutronix.de (Uwe Kleine-König)
To: linux-arm-kernel@lists.infradead.org
Subject: drivers/rtc/rtc-pl031.c uses __raw_readl()?
Date: Tue, 17 Nov 2009 11:02:56 +0100 [thread overview]
Message-ID: <20091117100256.GC7407@pengutronix.de> (raw)
In-Reply-To: <63386a3d0911120043y2143c7f5w7289bc83b2e31847@mail.gmail.com>
On Thu, Nov 12, 2009 at 09:43:43AM +0100, Linus Walleij wrote:
> 2009/11/11 Linus Walleij <linus.ml.walleij@gmail.com>:
>
> > Is there some special reason as to why drivers/rtc/rtc-pl031.c uses
> > the __raw_[read|write]l() macro instead of plain [read|write]l()?
>
> Reading the macro definitions I come to the conclusion that readl()
> is always little-endian and __raw_readl() is the machine endianness,
Actually the readl part is not necessarily true I think.
At least arch/arm/mach-bcmring/include/mach/io.h has:
/* Do not enable mem_pci for a big endian arm architecture or unexpected byteswaps will */
/* happen in readw/writew etc. */
#define readb(c) __raw_readb(c)
...
But maybe this is a bug in mach-bcmring?! Or a work-around of drivers
using readb et al in wrong sitatations?
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2009-11-17 10:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-11 9:30 drivers/rtc/rtc-pl031.c uses __raw_readl()? Linus Walleij
2009-11-12 8:43 ` Linus Walleij
2009-11-13 23:26 ` Russell King - ARM Linux
2009-11-19 9:43 ` Russell King - ARM Linux
2009-11-19 10:49 ` Russell King - ARM Linux
2009-11-17 10:02 ` Uwe Kleine-König [this message]
2009-11-18 22:19 ` Leo (Hao) Chen
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