From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH v7 11/17] ACPI / processor: Make it possible to get CPU hardware ID via GICC Date: Tue, 20 Jan 2015 16:16:46 +0000 Message-ID: <20150120161646.GJ5398@red-moon> References: <1421247905-3749-1-git-send-email-hanjun.guo@linaro.org> <1421247905-3749-12-git-send-email-hanjun.guo@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from foss-mx-na.foss.arm.com ([217.140.108.86]:39313 "EHLO foss-mx-na.foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751911AbbATQQw (ORCPT ); Tue, 20 Jan 2015 11:16:52 -0500 Content-Disposition: inline In-Reply-To: <1421247905-3749-12-git-send-email-hanjun.guo@linaro.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Hanjun Guo Cc: Catalin Marinas , "Rafael J. Wysocki" , Olof Johansson , Arnd Bergmann , Mark Rutland , "grant.likely@linaro.org" , Will Deacon , "graeme.gregory@linaro.org" , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Mark Brown , Rob Herring , Robert Richter , Randy Dunlap , Charles Garcia-Tobin , "phoenix.liyi@huawei.com" , Timur Tabi , "suravee.suthikulpanit@amd.com" , wangyijing@huawei.com On Wed, Jan 14, 2015 at 03:04:59PM +0000, Hanjun Guo wrote: > Introduce a new function map_gicc_mpidr() to allow MPIDRs to be obtained > from the GICC Structure introduced by ACPI 5.1. > > MPIDR is the CPU hardware ID as local APIC ID on x86 platform, so we use > MPIDR not the GIC CPU interface ID to identify CPUs. > > Tested-by: Suravee Suthikulpanit > Tested-by: Yijing Wang > Signed-off-by: Hanjun Guo > --- > arch/arm64/include/asm/acpi.h | 29 +++++++++++++++++++++++++++++ > arch/arm64/kernel/acpi.c | 1 - > drivers/acpi/processor_core.c | 37 +++++++++++++++++++++++++++++++++++++ > 3 files changed, 66 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index c82d4a1..639bb2a 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -12,6 +12,8 @@ > #ifndef _ASM_ACPI_H > #define _ASM_ACPI_H > > +#include > + > /* Basic configuration for ACPI */ > #ifdef CONFIG_ACPI > #define acpi_strict 1 /* No out-of-spec workarounds on ARM64 */ > @@ -45,6 +47,33 @@ static inline void enable_acpi(void) > acpi_noirq = 0; > } > > +/* MPIDR value provided in GICC structure is 64 bits, but the > + * existing apic_id (CPU hardware ID) using in acpi processor > + * driver is 32-bit, to conform to the same datatype we need > + * to repack the GICC structure MPIDR. > + * > + * Only 32 bits of MPIDR are used: > + * > + * Bits [0:7] Aff0; > + * Bits [8:15] Aff1; > + * Bits [16:23] Aff2; > + * Bits [32:39] Aff3; > + */ > +static inline u32 pack_mpidr(u64 mpidr) > +{ > + return (u32) ((mpidr & 0xff00000000) >> 8) | mpidr; > +} > + > +/* > + * The ACPI processor driver for ACPI core code needs this macro > + * to find out this cpu was already mapped (mapping from CPU hardware > + * ID to CPU logical ID) or not. > + * > + * cpu_logical_map(cpu) is the mapping of MPIDR and the logical cpu, > + * and MPIDR is the cpu hardware ID we needed to pack. > + */ > +#define cpu_physical_id(cpu) pack_mpidr(cpu_logical_map(cpu)) Do we need this mpidr packing only because in drivers/acpi/processor_core.c phys_id is defined as an int ? What you could do, is to typedef a cpuid_t type in arch code (with appropriate size and a corresponding invalid value, say ~0) and use that instead of an int in drivers/acpi/processor_core.c to store phys_id. phys_id is used as an error value too (ie -1 as a magic number), see drivers/acpi/acpi_processor.c, retrieved through acpi_get_phys_id(), it should not be that difficult to change the parsing API to keep current code behaviour unchanged and define at the same time a proper type for the cpu physical identifier, with no mpidr packing needed whatsoever. Thanks, Lorenzo