From: Ralf Baechle <ralf@linux-mips.org>
To: Manuel Lauss <manuel.lauss@googlemail.com>
Cc: Linux-MIPS <linux-mips@linux-mips.org>
Subject: Re: Reason for PIO_MASK?
Date: Tue, 6 Oct 2009 13:52:20 +0200 [thread overview]
Message-ID: <20091006115220.GC25263@linux-mips.org> (raw)
In-Reply-To: <f861ec6f0910030748l396b45bck858f15460354e58e@mail.gmail.com>
On Sat, Oct 03, 2009 at 04:48:12PM +0200, Manuel Lauss wrote:
> In arch/mips/lib/iomap.c there's this "#define PIO_MASK 0x0ffff"
> which limits the ability to successfully call ioport_map() to the
> first 64kB. This causes pata_pcmcia to error out on CF card
> probe because devm_ioport_map() is called with the remapped
> PCMCIA IO area, which is somewhere in MAP_BASE space.
Remapped, so that then actually be a physical address? That'd be wrong.
> I've temporarily removed the PIO_MASK check and pata_pcmcia
> works as expected. Is there any way around this, other than
> creating an Alchemy-specific ioport_map() function?
The provocative question - why would you want to have more than 64k I/O port
space?
I/O ports are x86 legacy and deprecated. PCI limits allocations to at
most 256 bytes and I don't know of any devices that even come close to
that.
When I wrote ioport_map I reviwed all uses of ioport addresses > 64k and
found each of them to be buggy ...
Ralf
next prev parent reply other threads:[~2009-10-06 11:51 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-03 14:48 Reason for PIO_MASK? Manuel Lauss
2009-10-06 11:52 ` Ralf Baechle [this message]
2009-10-06 12:11 ` Manuel Lauss
2009-10-06 14:25 ` Ralf Baechle
2009-10-06 14:59 ` Manuel Lauss
2009-10-07 15:49 ` Sergei Shtylyov
2009-10-07 16:07 ` Manuel Lauss
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