From mboxrd@z Thu Jan 1 00:00:00 1970 From: juri.lelli@arm.com (Juri Lelli) Date: Wed, 13 Aug 2014 12:14:40 +0100 Subject: [PATCH] cpuidle/cpuidle-big_little: fix reading cpu id part number In-Reply-To: <20140813104431.GJ30401@n2100.arm.linux.org.uk> References: <1407501757-15231-1-git-send-email-juri.lelli@arm.com> <20140808132105.GB30282@n2100.arm.linux.org.uk> <20140808164737.GB11623@e102568-lin.cambridge.arm.com> <53EB381D.7080604@arm.com> <20140813104431.GJ30401@n2100.arm.linux.org.uk> Message-ID: <53EB48A0.3040204@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 13/08/14 11:44, Russell King - ARM Linux wrote: > On Wed, Aug 13, 2014 at 11:04:13AM +0100, Juri Lelli wrote: >> Thanks a lot for the comment. Does what below address it? > > Yes, thanks, but a few of nitpicks though. > >> +/* >> + * smp_cpuid_part() - return part id for a given cpu >> + * >> + * @cpu: logical cpu id >> + * >> + * Return: part id of logical cpu passed as argument >> + * >> + */ > > If this is supposed to be a kerneldoc-compatible comment, please read > Documentation/kernel-doc-nano-HOWTO.txt for the correct format. > >> +static inline unsigned int smp_cpuid_part(int cpu) >> +{ >> + struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpu); >> + >> + return is_smp() ? (cpu_info->cpuid & ARM_CPU_PART_MASK) : > > Parens are not required, and there's a double space before &. > > The BNF for the ?: operator is: > > cond-expr: > log-or-expr ? expr : cond-expr > > So the compiler knows that whatever is between the ? and : is a single > expression, and the parens are surplus. > >> -static int __init bl_idle_driver_init(struct cpuidle_driver *drv, int cpu_id) >> +static int __init bl_idle_driver_init(struct cpuidle_driver *drv, int match_id) > > If we're changing the name, "part_id" would probably be better than the > opaque "match_id" here. > Right, thanks! What follows has those fixed. Should I send it as a new post? Thanks, - Juri >>From 61b88de0f021213f894e843c8e4673203f953ca9 Mon Sep 17 00:00:00 2001 From: Juri Lelli Date: Thu, 7 Aug 2014 17:26:54 +0100 Subject: [PATCH] cpuidle/cpuidle-big_little: fix reading cpu id part number Commit af040ffc9ba1e079ee4c0748aff64fa3d4716fa5 by Russell King changed ARM_CPU_PART_X masks, and the way they are returned and checked against. Usage of read_cpuid_part_number() is now deprecated, and calling places updated accordingly. This actually broke cpuidle-big_little initialization, as bl_idle_driver_init() performs a check using and hardcoded mask on cpu_id. Create an interface to perform the check (that is now even easier to read). Define also a proper mask (ARM_CPU_PART_MASK) that makes this kind of checks cleaner and helps preventing bugs in the future. Update usage accordingly. Signed-off-by: Juri Lelli Signed-off-by: Lorenzo Pieralisi --- arch/arm/include/asm/cputype.h | 3 ++- arch/arm/include/asm/smp_plat.h | 15 +++++++++++++++ drivers/cpuidle/cpuidle-big_little.c | 13 +++---------- 3 files changed, 20 insertions(+), 11 deletions(-) diff --git a/arch/arm/include/asm/cputype.h b/arch/arm/include/asm/cputype.h index 963a251..819777d 100644 --- a/arch/arm/include/asm/cputype.h +++ b/arch/arm/include/asm/cputype.h @@ -74,6 +74,7 @@ #define ARM_CPU_PART_CORTEX_A12 0x4100c0d0 #define ARM_CPU_PART_CORTEX_A17 0x4100c0e0 #define ARM_CPU_PART_CORTEX_A15 0x4100c0f0 +#define ARM_CPU_PART_MASK 0xff00fff0 #define ARM_CPU_XSCALE_ARCH_MASK 0xe000 #define ARM_CPU_XSCALE_ARCH_V1 0x2000 @@ -179,7 +180,7 @@ static inline unsigned int __attribute_const__ read_cpuid_implementor(void) */ static inline unsigned int __attribute_const__ read_cpuid_part(void) { - return read_cpuid_id() & 0xff00fff0; + return read_cpuid_id() & ARM_CPU_PART_MASK; } static inline unsigned int __attribute_const__ __deprecated read_cpuid_part_number(void) diff --git a/arch/arm/include/asm/smp_plat.h b/arch/arm/include/asm/smp_plat.h index a252c0b..0ad7d49 100644 --- a/arch/arm/include/asm/smp_plat.h +++ b/arch/arm/include/asm/smp_plat.h @@ -8,6 +8,7 @@ #include #include +#include #include /* @@ -25,6 +26,20 @@ static inline bool is_smp(void) #endif } +/** + * smp_cpuid_part() - return part id for a given cpu + * @cpu: logical cpu id. + * + * Return: part id of logical cpu passed as argument. + */ +static inline unsigned int smp_cpuid_part(int cpu) +{ + struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpu); + + return is_smp() ? cpu_info->cpuid & ARM_CPU_PART_MASK : + read_cpuid_part(); +} + /* all SMP configurations have the extended CPUID registers */ #ifndef CONFIG_MMU #define tlb_ops_need_broadcast() 0 diff --git a/drivers/cpuidle/cpuidle-big_little.c b/drivers/cpuidle/cpuidle-big_little.c index 344d79fa..ef94c3b 100644 --- a/drivers/cpuidle/cpuidle-big_little.c +++ b/drivers/cpuidle/cpuidle-big_little.c @@ -138,25 +138,18 @@ static int bl_enter_powerdown(struct cpuidle_device *dev, return idx; } -static int __init bl_idle_driver_init(struct cpuidle_driver *drv, int cpu_id) +static int __init bl_idle_driver_init(struct cpuidle_driver *drv, int part_id) { - struct cpuinfo_arm *cpu_info; struct cpumask *cpumask; - unsigned long cpuid; int cpu; cpumask = kzalloc(cpumask_size(), GFP_KERNEL); if (!cpumask) return -ENOMEM; - for_each_possible_cpu(cpu) { - cpu_info = &per_cpu(cpu_data, cpu); - cpuid = is_smp() ? cpu_info->cpuid : read_cpuid_id(); - - /* read cpu id part number */ - if ((cpuid & 0xFFF0) == cpu_id) + for_each_possible_cpu(cpu) + if (smp_cpuid_part(cpu) == part_id) cpumask_set_cpu(cpu, cpumask); - } drv->cpumask = cpumask; -- 2.0.4