From: Arnd Bergmann <arnd@arndb•de>
To: linuxppc-embedded@ozlabs•org
Cc: linuxppc@ozlabs•org, Domen Puncer <domen.puncer@telargo•com>
Subject: Re: a question on "iowrite32()"
Date: Thu, 7 Jun 2007 12:01:46 +0200 [thread overview]
Message-ID: <200706071201.46637.arnd@arndb.de> (raw)
In-Reply-To: <20070607062054.GD23294@moe.telargo.com>
On Thursday 07 June 2007, Domen Puncer wrote:
> out_be32?
> I recall something about iowrite32 being PCI stuff and therefore little
> endian, but don't count on this being right.
You're completely right, out_be32 is the correct one. The primitives
we have for writing 32 bit I/O space are:
writel(): PCI memory space from ioremap
outl(): PCI I/O space from a struct resource
iowrite32(): PCI memory or I/O space from pci_iomap
iowrite32be(): defined but not useful anywhere currently
out_be32(): big-endian memory address from of_address_to_resource or of_iomap
out_le32(): like out_be32(), but little-endian
__raw_writel(): always broken, don't use
Since of_iomap() is rather new and hardly used by any drivers, we
could still redefine it so that you would use iowrite32{,be}() instead
of out_{be,le}32, but currently that doesn't work.
I also thought about changing of_iomap() to use the devres functions,
which basically attach information about the mapping to the device
structure, and automatically unmap those when the of_platform_driver
gets unregistered.
Arnd <><
next prev parent reply other threads:[~2007-06-07 10:07 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-06 19:30 a question on "iowrite32()" Ming Liu
2007-06-07 6:20 ` Domen Puncer
2007-06-07 10:01 ` Arnd Bergmann [this message]
2007-06-07 11:20 ` Ming Liu
2007-06-07 14:09 ` Arnd Bergmann
2007-06-08 13:51 ` Ming Liu
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