From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 0598D1A01F4 for ; Thu, 13 Nov 2014 11:45:49 +1100 (AEDT) Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 529CC1400B6 for ; Thu, 13 Nov 2014 11:45:48 +1100 (AEDT) Message-ID: <1415839522.5124.58.camel@kernel.crashing.org> Subject: Re: [PATCH] of/base: Fix PowerPC address parsing hack From: Benjamin Herrenschmidt To: Stephen Rothwell Date: Thu, 13 Nov 2014 11:45:22 +1100 In-Reply-To: <1415833725.5124.53.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> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Cc: "devicetree@vger.kernel.org" , Arnd Bergmann , linuxppc-dev@ozlabs.org, "linux-kernel@vger.kernel.org" , Olof Johansson , Rob Herring , Grant Likely List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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: 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 (quirk_state < 0) + quirk_state = of_machine_is_compatible("Power Macintosh") || + of_machine_is_compatible("MacRISC"); + return quirk_state; +} + 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);