From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH v2 2/5] ARM: kernel: add device tree init map function Date: Tue, 13 Nov 2012 10:06:59 +0000 Message-ID: <20121113100659.GF12287@e102568-lin.cambridge.arm.com> References: <1352471654-20207-1-git-send-email-lorenzo.pieralisi@arm.com> <1352471654-20207-3-git-send-email-lorenzo.pieralisi@arm.com> <20121112172753.GB2111@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20121112172753.GB2111@linaro.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Dave Martin Cc: Mark Rutland , Nicolas Pitre , Kukjin Kim , Russell King , Pawel Moll , Stephen Warren , Tony Lindgren , Catalin Marinas , "devicetree-discuss@lists.ozlabs.org" , Will Deacon , Amit Kucheria , Grant Likely , "rob.herring@calxeda.com" , Benjamin Herrenschmidt , David Brown , Magnus Damm , "linux-arm-kernel@lists.infradead.org" List-Id: devicetree@vger.kernel.org On Mon, Nov 12, 2012 at 05:27:53PM +0000, Dave Martin wrote: > On Fri, Nov 09, 2012 at 02:34:11PM +0000, Lorenzo Pieralisi wrote: [...] > > +Every cpu node is required to set its device_type to "cpu". > > + > > +Example: > > + > > + cpus { > > + #size-cells = <0>; > > + #address-cells = <1>; > > + > > + CPU0: cpu@0 { > > + device_type = "cpu"; > > + compatible = ; > > + reg = <0x0>; > > + }; > > + > > + CPU1: cpu@1 { > > + device_type = "cpu"; > > + compatible = ; > > + reg = <0x1>; > > + }; > > + > > + CPU2: cpu@100 { > > + device_type = "cpu"; > > + compatible = ; > > + reg = <0x100>; > > + }; > > + > > + CPU3: cpu@101 { > > Should we document the unit address convention as part of the binding > documentation? > > Using the MPIDR value here is a bit cumbersome, but I'm not sure if > there's a better alternative, unless we make a multi-element vector > out of the MPIDR to use as the address -- sounds like overkill. I just followed the booting-without-of.txt convention for /cpu nodes, where the unit-address is just the reg property stripped of its leading zeros. I think it is the default way of defining the unit-address I do not know if I need to add to this, I certainly can. > > + device_type = "cpu"; > > + compatible = ; > > + reg = <0x101>; > > + }; > > + }; > > diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h > > index aeae9c6..8dd51dc 100644 > > --- a/arch/arm/include/asm/prom.h > > +++ b/arch/arm/include/asm/prom.h > > @@ -15,6 +15,7 @@ > > > > extern struct machine_desc *setup_machine_fdt(unsigned int dt_phys); > > extern void arm_dt_memblock_reserve(void); > > +extern void __init arm_dt_init_cpu_maps(void); > > > > #else /* CONFIG_OF */ > > > > @@ -24,6 +25,7 @@ static inline struct machine_desc *setup_machine_fdt(unsigned int dt_phys) > > } > > > > static inline void arm_dt_memblock_reserve(void) { } > > +static inline void arm_dt_init_cpu_maps(void) { } > > > > #endif /* CONFIG_OF */ > > #endif /* ASMARM_PROM_H */ > > diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c > > index bee7f9d..d64d222 100644 > > --- a/arch/arm/kernel/devtree.c > > +++ b/arch/arm/kernel/devtree.c > > @@ -19,8 +19,10 @@ > > #include > > #include > > > > +#include > > #include > > #include > > +#include > > #include > > #include > > > > @@ -61,6 +63,80 @@ void __init arm_dt_memblock_reserve(void) > > } > > } > > > > +/* > > + * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree > > + * and builds the cpu logical map array containing MPIDR values related to > > + * logical cpus > > + * > > + * Updates the cpu possible mask with the number of parsed cpu nodes > > + */ > > Can this function sanity-check that we do not assign the same MPIDR > value for multiple logical CPUs? > > It turns out to be surprisingly easy to write a DT with duplicate reg > properties in the CPUs node due to careless cut-and-paste. (i.e., I > did it, but have been getting away with it up to now). Check added. Waiting for some comments on the compatible list of ids to post v3. Thanks a lot, Lorenzo