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			138 lines
		
	
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			138 lines
		
	
	
	
		
			3.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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|  *
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|  * This program is free software; you can redistribute it and/or modify
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|  * it under the terms of the GNU General Public License version 2 as
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|  * published by the Free Software Foundation.
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|  */
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| 
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| #ifndef __ASM_ARC_SMP_H
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| #define __ASM_ARC_SMP_H
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| 
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| #ifdef CONFIG_SMP
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| 
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| #include <linux/types.h>
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| #include <linux/init.h>
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| #include <linux/threads.h>
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| 
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| #define raw_smp_processor_id() (current_thread_info()->cpu)
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| 
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| /* including cpumask.h leads to cyclic deps hence this Forward declaration */
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| struct cpumask;
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| 
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| /*
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|  * APIs provided by arch SMP code to generic code
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|  */
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| extern void arch_send_call_function_single_ipi(int cpu);
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| extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
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| 
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| /*
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|  * APIs provided by arch SMP code to rest of arch code
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|  */
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| extern void __init smp_init_cpus(void);
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| extern void first_lines_of_secondary(void);
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| extern const char *arc_platform_smp_cpuinfo(void);
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| 
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| /*
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|  * API expected BY platform smp code (FROM arch smp code)
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|  *
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|  * smp_ipi_irq_setup:
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|  *	Takes @cpu and @irq to which the arch-common ISR is hooked up
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|  */
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| extern int smp_ipi_irq_setup(int cpu, int irq);
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| 
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| /*
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|  * struct plat_smp_ops	- SMP callbacks provided by platform to ARC SMP
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|  *
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|  * @info:		SoC SMP specific info for /proc/cpuinfo etc
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|  * @cpu_kick:		For Master to kickstart a cpu (optionally at a PC)
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|  * @ipi_send:		To send IPI to a @cpu
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|  * @ips_clear:		To clear IPI received at @irq
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|  */
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| struct plat_smp_ops {
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| 	const char 	*info;
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| 	void		(*cpu_kick)(int cpu, unsigned long pc);
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| 	void		(*ipi_send)(int cpu);
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| 	void		(*ipi_clear)(int irq);
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| };
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| 
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| /* TBD: stop exporting it for direct population by platform */
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| extern struct plat_smp_ops  plat_smp_ops;
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| 
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| #else /* CONFIG_SMP */
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| 
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| static inline void smp_init_cpus(void) {}
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| static inline const char *arc_platform_smp_cpuinfo(void)
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| {
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| 	return "";
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| }
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| 
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| #endif  /* !CONFIG_SMP */
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| 
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| /*
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|  * ARC700 doesn't support atomic Read-Modify-Write ops.
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|  * Originally Interrupts had to be disabled around code to gaurantee atomicity.
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|  * The LLOCK/SCOND insns allow writing interrupt-hassle-free based atomic ops
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|  * based on retry-if-irq-in-atomic (with hardware assist).
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|  * However despite these, we provide the IRQ disabling variant
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|  *
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|  * (1) These insn were introduced only in 4.10 release. So for older released
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|  *	support needed.
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|  *
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|  * (2) In a SMP setup, the LLOCK/SCOND atomiticity across CPUs needs to be
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|  *	gaurantted by the platform (not something which core handles).
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|  *	Assuming a platform won't, SMP Linux needs to use spinlocks + local IRQ
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|  *	disabling for atomicity.
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|  *
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|  *	However exported spinlock API is not usable due to cyclic hdr deps
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|  *	(even after system.h disintegration upstream)
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|  *	asm/bitops.h -> linux/spinlock.h -> linux/preempt.h
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|  *		-> linux/thread_info.h -> linux/bitops.h -> asm/bitops.h
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|  *
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|  *	So the workaround is to use the lowest level arch spinlock API.
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|  *	The exported spinlock API is smart enough to be NOP for !CONFIG_SMP,
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|  *	but same is not true for ARCH backend, hence the need for 2 variants
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|  */
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| #ifndef CONFIG_ARC_HAS_LLSC
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| 
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| #include <linux/irqflags.h>
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| #ifdef CONFIG_SMP
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| 
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| #include <asm/spinlock.h>
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| 
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| extern arch_spinlock_t smp_atomic_ops_lock;
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| extern arch_spinlock_t smp_bitops_lock;
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| 
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| #define atomic_ops_lock(flags)	do {		\
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| 	local_irq_save(flags);			\
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| 	arch_spin_lock(&smp_atomic_ops_lock);	\
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| } while (0)
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| 
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| #define atomic_ops_unlock(flags) do {		\
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| 	arch_spin_unlock(&smp_atomic_ops_lock);	\
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| 	local_irq_restore(flags);		\
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| } while (0)
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| 
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| #define bitops_lock(flags)	do {		\
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| 	local_irq_save(flags);			\
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| 	arch_spin_lock(&smp_bitops_lock);	\
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| } while (0)
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| 
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| #define bitops_unlock(flags) do {		\
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| 	arch_spin_unlock(&smp_bitops_lock);	\
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| 	local_irq_restore(flags);		\
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| } while (0)
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| 
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| #else /* !CONFIG_SMP */
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| 
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| #define atomic_ops_lock(flags)		local_irq_save(flags)
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| #define atomic_ops_unlock(flags)	local_irq_restore(flags)
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| 
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| #define bitops_lock(flags)		local_irq_save(flags)
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| #define bitops_unlock(flags)		local_irq_restore(flags)
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| 
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| #endif /* !CONFIG_SMP */
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| 
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| #endif	/* !CONFIG_ARC_HAS_LLSC */
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| 
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| #endif
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