MIME-Version: 1.0
In-Reply-To: <20150701065948.GA4355@lst.de>
References: <20150622081028.35954.89885.stgit@dwillia2-desk3.jf.intel.com>
	<20150622082427.35954.73529.stgit@dwillia2-desk3.jf.intel.com>
	<20150622161002.GB8240@lst.de>
	<CAPcyv4h5OXyRvZvLGD5ZknO-YUPn675YGv0XdtW1QOO9qmZsug@mail.gmail.com>
	<20150701062352.GA3739@lst.de>
	<CAMuHMdUO4uSWH1Qc0SfDTLuXbiG2N9fq8Tf6j+3RoqVKdPugbA@mail.gmail.com>
	<20150701065948.GA4355@lst.de>
Date: Wed, 1 Jul 2015 09:19:29 +0200
Message-ID: <CAMuHMdXqjmo2T3V=msZySVSu2j4YjyE7FnVXWTjySEyfYLSg1A@mail.gmail.com>
Subject: Re: [PATCH v5 2/6] arch: unify ioremap prototypes and macro aliases
From: Geert Uytterhoeven <geert@linux-m68k.org>
To: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>, Arnd Bergmann <arnd@arndb.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
        Ross Zwisler <ross.zwisler@linux.intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Juergen Gross <jgross@suse.com>, X86 ML <x86@kernel.org>,
        "Kani, Toshimitsu" <toshi.kani@hp.com>,
        "linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Luis Rodriguez <mcgrof@suse.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Stefan Bader <stefan.bader@canonical.com>,
        Andy Lutomirski <luto@amacapital.net>, Linux MM <linux-mm@kvack.org>,
        Ralf Baechle <ralf@linux-mips.org>,
        Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
        Michael Ellerman <mpe@ellerman.id.au>, Tejun Heo <tj@kernel.org>,
        Paul Mackerras <paulus@samba.org>,
        Russell King - ARM Linux <linux@arm.linux.org.uk>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Content-Type: text/plain; charset=UTF-8
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1475
Lines: 37

On Wed, Jul 1, 2015 at 8:59 AM, Christoph Hellwig <hch@lst.de> wrote:
> On Wed, Jul 01, 2015 at 08:55:57AM +0200, Geert Uytterhoeven wrote:
>> >
>> > I think doing this at runtime might be a better idea.  E.g. a
>> > ioremap_flags with the CACHED argument will return -EOPNOTSUP unless
>> > actually implemented.  On various architectures different CPUs or
>> > boards will have different capabilities in this area.
>>
>> So it would be the responsibility of the caller to fall back from
>> ioremap(..., CACHED) to ioremap(..., UNCACHED)?
>> I.e. all drivers using it should be changed...
>
> All of the zero users we currently have will need to be changed, yes.

Good. Less work to convert all of these ;-)

> Note that I propose to leave ioremap(), aka ioremap_flags(..., 0) as
> a default that always has to work, -EOPNOTSUP is only a valid return
> value for non-default flaga.

OK.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/