linux-kernel - Re: [PATCH] Clarify pci_iomap() usage for MMIO-only devices

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Message-ID: <43e72e890709181312sf2b421cn49be3389b3786a2a@mail.gmail.com>
Date:	Tue, 18 Sep 2007 16:12:56 -0400
From:	"Luis R. Rodriguez" <mcgrof@...il.com>
To:	"Linus Torvalds" <torvalds@...ux-foundation.org>
Cc:	"Alan Cox" <alan@...rguk.ukuu.org.uk>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	"Jeff Garzik" <jeff@...zik.org>,
	"John W. Linville" <linville@...driver.com>,
	linux-wireless <linux-wireless@...r.kernel.org>
Subject: Re: [PATCH] Clarify pci_iomap() usage for MMIO-only devices

On 9/18/07, Linus Torvalds <torvalds@...ux-foundation.org> wrote:
>
>
> On Tue, 18 Sep 2007, Luis R. Rodriguez wrote:
> >
> > ACK -- driver developers use this just to save themselves a few lines
> > from calling pci_resource_start() and friends. How about having an
> > inline which does what pci_iomap() does except it doesn't call
> > ioport_map() ? I am just not sure where this would go..
>
> I'm not understanding what the problem is?
>
> Why don't these people just use "ioread*()/iowrite*()"?
>
> In other words, the whole point of *not* using "read*/write*()" is that
> you get a whole slew of much nicer interfaces.
>
> So can people explain this fundamental issue? Why do people insist on
> using the old interfaces (and matching them with the new setup)?

An extra branch is created on MMIO-only devices on read/writes on the
IO_COND macro using this interface -- or is this optimized out?

  Luis
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