Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933051AbaKMMy2 (ORCPT ); Thu, 13 Nov 2014 07:54:28 -0500 Received: from gate.crashing.org ([63.228.1.57]:52650 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932498AbaKMMy0 (ORCPT ); Thu, 13 Nov 2014 07:54:26 -0500 Message-ID: <1415883227.666.6.camel@kernel.crashing.org> Subject: Re: [PATCH] of/base: Fix PowerPC address parsing hack From: Benjamin Herrenschmidt To: Grant Likely Cc: Stephen Rothwell , Rob Herring , Olof Johansson , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Arnd Bergmann , linuxppc-dev Date: Thu, 13 Nov 2014 23:53:47 +1100 In-Reply-To: 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> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.7-0ubuntu1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-11-13 at 12:44 +0000, Grant Likely wrote: > 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. I'd like some distro to pick it up in 3.16 > > 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. Yeah, I'm set in my ways, keep forgetting about all the shiny new stuff. > > +} > > + > > 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 devicetree" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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/