Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932812AbaKMMom (ORCPT ); Thu, 13 Nov 2014 07:44:42 -0500 Received: from mail-ie0-f176.google.com ([209.85.223.176]:35148 "EHLO mail-ie0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932639AbaKMMok (ORCPT ); Thu, 13 Nov 2014 07:44:40 -0500 MIME-Version: 1.0 In-Reply-To: <1415839522.5124.58.camel@kernel.crashing.org> References: <1415771461.5124.33.camel@kernel.crashing.org> <20141113091036.4e9ec43d@canb.auug.org.au> <1415833725.5124.53.camel@kernel.crashing.org> <1415839522.5124.58.camel@kernel.crashing.org> From: Grant Likely Date: Thu, 13 Nov 2014 12:44:19 +0000 X-Google-Sender-Auth: 92YafDxlLqSZVd24JZ7fNiKNGVI Message-ID: Subject: Re: [PATCH] of/base: Fix PowerPC address parsing hack To: Benjamin Herrenschmidt Cc: Stephen Rothwell , Rob Herring , Olof Johansson , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Arnd Bergmann , linuxppc-dev Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 13, 2014 at 12:45 AM, Benjamin Herrenschmidt wrote: > What about this one instead ? I want to cache it because that function > can be called quite a while and doing two additional property lookup > and string compares every time might hurt some platforms. > > ---- > > We have a historical hack that treats missing ranges properties as the > equivalent of an empty one. This is needed for ancient PowerMac "bad" > device-trees, and shouldn't be enabled for any other PowerPC platform, > otherwise we get some nasty layout of devices in sysfs or even > duplication when a set of otherwise identically named devices is > created multiple times under a different parent node with no ranges > property. > > This fix is needed for the PowerNV i2c busses to be exposed properly > and will fix a number of other embedded cases. > > Signed-off-by: Benjamin Herrenschmidt > CC: How far back does this need to go? I assume I need to get this in for v3.18. > > diff --git a/drivers/of/address.c b/drivers/of/address.c > index e371825..5eae0cd 100644 > --- a/drivers/of/address.c > +++ b/drivers/of/address.c > @@ -403,6 +403,17 @@ static struct of_bus *of_match_bus(struct device_node *np) > return NULL; > } > > +static int of_empty_ranges_quirk(void) > +{ > + /* To save cycles, we cache the result */ > + static int quirk_state = -1; > + if (IS_ENABLED(CONFIG_POWERPC)) { > + if (quirk_state < 0) > + quirk_state = of_machine_is_compatible("Power Macintosh") || > + of_machine_is_compatible("MacRISC"); > + return quirk_state; } return 0; So it gets compiled out for non powerpc. > +} > + > static int of_translate_one(struct device_node *parent, struct of_bus *bus, > struct of_bus *pbus, __be32 *addr, > int na, int ns, int pna, const char *rprop) > @@ -428,12 +439,10 @@ static int of_translate_one(struct device_node *parent, struct of_bus *bus, > * This code is only enabled on powerpc. --gcl > */ > ranges = of_get_property(parent, rprop, &rlen); > -#if !defined(CONFIG_PPC) > - if (ranges == NULL) { > + if (ranges == NULL && !of_empty_ranges_quirk()) { > pr_err("OF: no ranges; cannot translate\n"); > return 1; > } > -#endif /* !defined(CONFIG_PPC) */ > if (ranges == NULL || rlen == 0) { > offset = of_read_number(addr, na); > memset(addr, 0, pna * 4); > > -- 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/