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From: Arnd Bergmann <arnd@arndb.de>
To: linuxppc-dev@ozlabs.org
Subject: Re: [PATCH] generic check_legacy_ioport
Date: Tue, 17 Apr 2007 23:22:22 +0200
References: <20070417210745.GA3567@aepfle.de>
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Cc: Olaf Hering <olaf@aepfle.de>
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On Tuesday 17 April 2007, Olaf Hering wrote:
>=20
> =A0int check_legacy_ioport(unsigned long base_port)
> =A0{
> -=A0=A0=A0=A0=A0=A0=A0if (ppc_md.check_legacy_ioport =3D=3D NULL)
> +=A0=A0=A0=A0=A0=A0=A0struct device_node *np;
> +=A0=A0=A0=A0=A0=A0=A0if (ppc_md.check_legacy_ioport =3D=3D NULL) {
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0np =3D of_find_node_by_type=
(NULL, "isa");
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0if (np =3D=3D NULL)
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0ret=
urn -ENODEV;
> +=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0of_node_put(np);
> =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0return 0;
> +=A0=A0=A0=A0=A0=A0=A0}
> =A0=A0=A0=A0=A0=A0=A0=A0return ppc_md.check_legacy_ioport(base_port);
> =A0}

I could be wrong, but I think I've seen fake 'isa' bus nodes in the device =
tree
for machines that don't actually have isa. I probably saw this on very early
cell blades (not the ones currently shipping), but perhaps others have
made the same mistake.

How about simply defining a new common function like

int generic_deny_legacy_ioport(unsigned long base_port)
{
	return -EINVAL;
}

so that not every platform has to define their own but can either
set ppc_md.check_legacy_ioport to NULL, to generic_deny_legacy_ioport
or their own function if they do something fancy?

	Arnd <><