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Message-ID: <20080805172324.45853d98@lappy.seanm.ca>
Date: Tue, 5 Aug 2008 17:23:24 -0400
From: Sean MacLennan <smaclennan@...atech.com>
To: "Karsten Keil" <kkeil@...e.de>
Cc: "Linus Torvalds" <torvalds@...ux-foundation.org>,
"Benjamin Herrenschmidt" <benh@...nel.crashing.org>,
"Andreas.Eversberg" <Andreas.Eversberg@...satel.de>,
<isdn4linux@...tserv.isdn4linux.de>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/4] Fix remaining big endian issue of hfcmulti
On Tue, 5 Aug 2008 23:02:39 +0200
"Karsten Keil" <kkeil@...e.de> wrote:
> On Tue, Aug 05, 2008 at 11:42:56AM -0700, Linus Torvalds wrote:
> >
> >
> > On Tue, 5 Aug 2008, Karsten Keil wrote:
> > >
> > > Maybe we can use the trick from lib/iomap.c to detect which
> > > kind of IO is needed, but unfortunately PIO_OFFSET, PIO_MASK and
> > > PIO_RESERVED are not exported so it would need to copy the
> > > defines, which isn't a really clean solution.
> >
> > Even if they were exported, you couldn't.
> >
> > lib/iomap.c is _not_ generic code. It's a library function for
> > architectures that don't do it some other way. But various
> > architectures can choose to not use lib/iomap.c at all - for
> > example, they may have MMIO and PIO in the same address space, so
> > they don't need the conditionals at all (because all the work was
> > done at mapping time, not at runtime).
> >
> > So if you actually have different models of operation for PIO and
> > MMIO, then yes, you need to handle that in the driver itself.
> >
>
> One question here, what is the better approach to do such a different
> implementation, use one local function like
>
> static void
> my_out32(struct card *c, u_int offset, u-int data)
> {
> if (c->mode == MMIO) {
> ...
> } else {
> ...
> }
> }
>
> or use 2 function, one for the MMIO and one for the PIO model and
> then use indirect calls (like c->my_out32(...)) ?
Why not select PIO or MMIO at config time?
Cheers,
Sean
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