c9018aab8e
The affinity between ARM processors is defined in the MPIDR register. We can identify which processors are in the same cluster, and which ones have performance interdependency. We can define the cpu topology of ARM platform, that is then used by sched_mc and sched_smt. The default state of sched_mc and sched_smt config is disable. When enabled, the behavior of the scheduler can be modified with sched_mc_power_savings and sched_smt_power_savings sysfs interfaces. Changes since v4 : * Remove unnecessary parentheses and blank lines Changes since v3 : * Update the format of printk message * Remove blank line Changes since v2 : * Update the commit message and some comments Changes since v1 : * Update the commit message * Add read_cpuid_mpidr in arch/arm/include/asm/cputype.h * Modify header of arch/arm/kernel/topology.c * Modify tests and manipulation of MPIDR's bitfields * Modify the place and dependancy of the config * Modify Noop functions Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
#ifndef __ASM_ARM_CPUTYPE_H
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#define __ASM_ARM_CPUTYPE_H
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#include <linux/stringify.h>
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#include <linux/kernel.h>
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#define CPUID_ID 0
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#define CPUID_CACHETYPE 1
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#define CPUID_TCM 2
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#define CPUID_TLBTYPE 3
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#define CPUID_MPIDR 5
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#define CPUID_EXT_PFR0 "c1, 0"
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#define CPUID_EXT_PFR1 "c1, 1"
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#define CPUID_EXT_DFR0 "c1, 2"
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#define CPUID_EXT_AFR0 "c1, 3"
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#define CPUID_EXT_MMFR0 "c1, 4"
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#define CPUID_EXT_MMFR1 "c1, 5"
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#define CPUID_EXT_MMFR2 "c1, 6"
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#define CPUID_EXT_MMFR3 "c1, 7"
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#define CPUID_EXT_ISAR0 "c2, 0"
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#define CPUID_EXT_ISAR1 "c2, 1"
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#define CPUID_EXT_ISAR2 "c2, 2"
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#define CPUID_EXT_ISAR3 "c2, 3"
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#define CPUID_EXT_ISAR4 "c2, 4"
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#define CPUID_EXT_ISAR5 "c2, 5"
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extern unsigned int processor_id;
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#ifdef CONFIG_CPU_CP15
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#define read_cpuid(reg) \
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({ \
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unsigned int __val; \
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asm("mrc p15, 0, %0, c0, c0, " __stringify(reg) \
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: "=r" (__val) \
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: \
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: "cc"); \
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__val; \
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})
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#define read_cpuid_ext(ext_reg) \
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({ \
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unsigned int __val; \
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asm("mrc p15, 0, %0, c0, " ext_reg \
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: "=r" (__val) \
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: \
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: "cc"); \
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__val; \
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})
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#else
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#define read_cpuid(reg) (processor_id)
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#define read_cpuid_ext(reg) 0
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#endif
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/*
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* The CPU ID never changes at run time, so we might as well tell the
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* compiler that it's constant. Use this function to read the CPU ID
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* rather than directly reading processor_id or read_cpuid() directly.
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*/
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static inline unsigned int __attribute_const__ read_cpuid_id(void)
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{
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return read_cpuid(CPUID_ID);
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}
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static inline unsigned int __attribute_const__ read_cpuid_cachetype(void)
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{
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return read_cpuid(CPUID_CACHETYPE);
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}
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static inline unsigned int __attribute_const__ read_cpuid_tcmstatus(void)
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{
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return read_cpuid(CPUID_TCM);
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}
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static inline unsigned int __attribute_const__ read_cpuid_mpidr(void)
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{
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return read_cpuid(CPUID_MPIDR);
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}
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/*
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* Intel's XScale3 core supports some v6 features (supersections, L2)
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* but advertises itself as v5 as it does not support the v6 ISA. For
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* this reason, we need a way to explicitly test for this type of CPU.
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*/
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#ifndef CONFIG_CPU_XSC3
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#define cpu_is_xsc3() 0
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#else
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static inline int cpu_is_xsc3(void)
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{
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unsigned int id;
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id = read_cpuid_id() & 0xffffe000;
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/* It covers both Intel ID and Marvell ID */
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if ((id == 0x69056000) || (id == 0x56056000))
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return 1;
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return 0;
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}
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#endif
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#if !defined(CONFIG_CPU_XSCALE) && !defined(CONFIG_CPU_XSC3)
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#define cpu_is_xscale() 0
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#else
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#define cpu_is_xscale() 1
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#endif
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#endif
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