From: Paul Mundt <lethal@linux-sh.org>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] fb.h: ARM uses __raw_{read/write}
Date: Mon, 13 Jun 2011 04:00:04 +0000 [thread overview]
Message-ID: <20110613040003.GA29731@linux-sh.org> (raw)
In-Reply-To: <201106101731.08578.hartleys@visionengravers.com>
On Fri, Jun 10, 2011 at 05:31:08PM -0700, H Hartley Sweeten wrote:
> ARM provides __raw_{read/write}* functions for memory access. These
> should be used instead of the default '(*(volatile' stuff to make sure the
> memory accesses are typesafe (void __iomem *).
>
> This also fixes a number of sparse warning like:
>
> warning: cast removes address space of expression
>
> Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
> Cc: Paul Mundt <lethal@linux-sh.org>
> Cc: Russell King <linux@arm.linux.org.uk>
>
I'm not sure what semantics are desirable for ARM here, so I'll wait for
Russell to reply.
This wrapping will basically mean that the fb_read/write ops are using
__raw_xxx variants while the memset and memcpy wrappers will be using the
regular read/write[bwl] routines which contain __iormb() calls. Given
that ioread/write and friends all wrap in to the normal versions with the
barriers, I would suppose that this is the default behaviour that is
desired, as opposed to wrapping in to the __raw_xxx variants directly.
next prev parent reply other threads:[~2011-06-13 4:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-11 0:31 [PATCH] fb.h: ARM uses __raw_{read/write} H Hartley Sweeten
2011-06-13 4:00 ` Paul Mundt [this message]
2011-06-13 10:08 ` Catalin Marinas
2011-06-13 13:37 ` Arnd Bergmann
2011-06-13 13:57 ` Russell King - ARM Linux
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