From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-bk0-x234.google.com (mail-bk0-x234.google.com [IPv6:2a00:1450:4008:c01::234]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 2FF4A2C024B for ; Sat, 17 Aug 2013 20:50:17 +1000 (EST) Received: by mail-bk0-f52.google.com with SMTP id e11so930673bkh.11 for ; Sat, 17 Aug 2013 03:50:11 -0700 (PDT) From: Tomasz Figa To: linux-arm-kernel@lists.infradead.org Subject: Re: [RFC PATCH v2 3/4] powerpc: refactor of_get_cpu_node to support other architectures Date: Sat, 17 Aug 2013 12:50:07 +0200 Message-ID: <2032060.4bgTKOdEX2@flatron> In-Reply-To: <1376674791-28244-2-git-send-email-Sudeep.KarkadaNagesha@arm.com> References: <1376586580-5409-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <1376674791-28244-1-git-send-email-Sudeep.KarkadaNagesha@arm.com> <1376674791-28244-2-git-send-email-Sudeep.KarkadaNagesha@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Jonas Bonn , devicetree@vger.kernel.org, Michal Simek , linux-pm@vger.kernel.org, Sudeep KarkadaNagesha , linux-kernel@vger.kernel.org, Rob Herring , "Rafael J. Wysocki" , Grant Likely , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hi Sudeep, This looks good to me overall, but I have one more question inline. On Friday 16 of August 2013 18:39:50 Sudeep KarkadaNagesha wrote: > From: Sudeep KarkadaNagesha > > Currently different drivers requiring to access cpu device node are > parsing the device tree themselves. Since the ordering in the DT need > not match the logical cpu ordering, the parsing logic needs to consider > that. However, this has resulted in lots of code duplication and in some > cases even incorrect logic. > > It's better to consolidate them by adding support for getting cpu > device node for a given logical cpu index in DT core library. However > logical to physical index mapping can be architecture specific. > > PowerPC has it's own implementation to get the cpu node for a given > logical index. > > This patch refactors the current implementation of of_get_cpu_node. > This in preparation to move the implementation to DT core library. > It separates out the logical to physical mapping so that a default > matching of the physical id to the logical cpu index can be added > when moved to common code. Architecture specific code can override it. > > Cc: Rob Herring > Cc: Grant Likely > Cc: Benjamin Herrenschmidt > Signed-off-by: Sudeep KarkadaNagesha > --- > arch/powerpc/kernel/prom.c | 76 > ++++++++++++++++++++++++++++------------------ 1 file changed, 47 > insertions(+), 29 deletions(-) > > diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c > index eb23ac9..fb12be6 100644 > --- a/arch/powerpc/kernel/prom.c > +++ b/arch/powerpc/kernel/prom.c > @@ -865,45 +865,63 @@ static int __init prom_reconfig_setup(void) > __initcall(prom_reconfig_setup); > #endif > > +bool arch_match_cpu_phys_id(int cpu, u64 phys_id) > +{ > + return (int)phys_id == get_hard_smp_processor_id(cpu); > +} > + > +static bool __of_find_n_match_cpu_property(struct device_node *cpun, > + const char *prop_name, int cpu, unsigned int *thread) > +{ > + const __be32 *cell; > + int ac, prop_len, tid; > + u64 hwid; > + > + ac = of_n_addr_cells(cpun); > + cell = of_get_property(cpun, prop_name, &prop_len); > + if (!cell) > + return false; I wonder how would this handle uniprocessor ARM (pre-v7) cores, for which the updated bindings[1] define #address-cells = <0> and so no reg property. [1] - http://thread.gmane.org/gmane.linux.ports.arm.kernel/260795 Best regards, Tomasz