From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Mike Turquette <mturquette@linaro.org>,
Linus Walleij <linus.walleij@linaro.org>,
Florian Fainelli <florian@openwrt.org>,
olof@lixom.net, devicetree-discuss@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/8] ARM: support for Moschip MCS814x SoCs
Date: Tue, 17 Jul 2012 12:16:40 +0200 [thread overview]
Message-ID: <20120717121640.589780ce@skate> (raw)
In-Reply-To: <201207161554.04812.arnd@arndb.de>
Le Mon, 16 Jul 2012 15:54:04 +0000,
Arnd Bergmann <arnd@arndb.de> a écrit :
> > +void mcs814x_restart(char mode, const char *cmd)
> > +{
> > + __raw_writel(~(1 << 31), mcs814x_sysdbg_base);
> > +}
>
> You should generally avoid using __raw_readl etc. and instead use
> readl/write or readl_relaxed/writel_relaxed.
I thought that readl/writel and readl_relaxed/writel_relaxed were used
for PCI-style access, for which these macros/functions do automatically
a conversion from the CPU-endianness to the PCI-endianness
(little-endian). Here of course, this the SoC is used little-endian, it
will just work because readl/writel will not do any endianness
conversion, but if we were on a big-endian machine?
My understanding until now was that __raw_readl/__raw_writel should be
used for accesses with native endianness, but apparently, it's more
subtle than this. Would you mind expanding a bit on this?
Best regards,
Thomas
--
Thomas Petazzoni, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
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next prev parent reply other threads:[~2012-07-17 10:16 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-15 14:49 [PATCH 0/8] ARM: support for Moschip MCS814x SoCs Florian Fainelli
2012-07-15 14:49 ` [PATCH 1/8] " Florian Fainelli
2012-07-16 12:29 ` Thomas Petazzoni
2012-07-16 12:43 ` Florian Fainelli
2012-07-16 15:55 ` Arnd Bergmann
2012-07-16 17:57 ` Nicolas Pitre
2012-07-23 19:11 ` Florian Fainelli
2012-07-27 22:42 ` Linus Walleij
[not found] ` <1342363754-30808-2-git-send-email-florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>
2012-07-16 15:54 ` Arnd Bergmann
[not found] ` <201207161554.04812.arnd-r2nGTMty4D4@public.gmane.org>
2012-07-16 20:47 ` Turquette, Mike
2012-07-17 9:41 ` Florian Fainelli
2012-07-17 10:47 ` Florian Fainelli
2012-07-16 22:12 ` Linus Walleij
2012-07-17 9:35 ` Florian Fainelli
2012-07-17 9:34 ` Florian Fainelli
2012-07-17 13:07 ` Arnd Bergmann
2012-07-17 13:32 ` Florian Fainelli
2012-07-17 13:45 ` Arnd Bergmann
2012-07-17 10:16 ` Thomas Petazzoni [this message]
2012-07-17 13:12 ` Arnd Bergmann
2012-07-17 13:28 ` Thomas Petazzoni
2012-07-17 13:51 ` Arnd Bergmann
2012-07-16 22:06 ` Linus Walleij
2012-07-15 14:49 ` [PATCH 2/8] ARM: MCS814x: add Device Tree based MCS8140 board support Florian Fainelli
[not found] ` <1342363754-30808-3-git-send-email-florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>
2012-07-17 13:19 ` Arnd Bergmann
2012-07-17 13:34 ` Florian Fainelli
2012-07-17 13:53 ` Arnd Bergmann
2012-07-17 13:57 ` Florian Fainelli
2012-07-15 14:49 ` [PATCH 3/8] ARM: MCS814x: add Device Tree bindings documentation Florian Fainelli
[not found] ` <1342363754-30808-4-git-send-email-florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>
2012-07-17 13:24 ` Arnd Bergmann
2012-07-17 13:35 ` Florian Fainelli
2012-07-15 14:49 ` [PATCH 4/8] ARM: MCS814X: add DTS file for Tigal/Robotech RBT-832 Florian Fainelli
[not found] ` <1342363754-30808-5-git-send-email-florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>
2012-07-17 13:27 ` Arnd Bergmann
2012-07-15 14:49 ` [PATCH 5/8] ARM: MCS814x: add DTS file for Devolo dLAN USB Extender Florian Fainelli
2012-07-15 14:49 ` [PATCH 6/8] ARM: MCS814x: provide a sample defconfig file Florian Fainelli
2012-07-15 14:49 ` [PATCH 7/8] ARM: MSC814X: add Kconfig and Makefile to arch/arm Florian Fainelli
2012-07-15 14:49 ` [PATCH 8/8] ARM: MSC814x: add MAINTAINERS entry Florian Fainelli
[not found] ` <1342363754-30808-1-git-send-email-florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>
2012-07-15 19:59 ` [PATCH 0/8] ARM: support for Moschip MCS814x SoCs Arnd Bergmann
2012-07-16 8:16 ` Florian Fainelli
[not found] ` <201207151959.19620.arnd-r2nGTMty4D4@public.gmane.org>
2012-07-16 18:09 ` Nicolas Pitre
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