1/* SPDX-License-Identifier: GPL-2.0-only */ 2/* 3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 4 */ 5 6#ifndef __ASM_ARC_SMP_H 7#define __ASM_ARC_SMP_H 8 9#ifdef CONFIG_SMP 10 11#include <linux/types.h> 12#include <linux/init.h> 13#include <linux/threads.h> 14 15#define raw_smp_processor_id() (current_thread_info()->cpu) 16 17/* including cpumask.h leads to cyclic deps hence this Forward declaration */ 18struct cpumask; 19 20/* 21 * APIs provided by arch SMP code to generic code 22 */ 23extern void arch_send_call_function_single_ipi(int cpu); 24extern void arch_send_call_function_ipi_mask(const struct cpumask *mask); 25 26/* 27 * APIs provided by arch SMP code to rest of arch code 28 */ 29extern void __init smp_init_cpus(void); 30extern void first_lines_of_secondary(void); 31extern const char *arc_platform_smp_cpuinfo(void); 32extern void arc_platform_smp_wait_to_boot(int); 33extern void start_kernel_secondary(void); 34 35/* 36 * API expected BY platform smp code (FROM arch smp code) 37 * 38 * smp_ipi_irq_setup: 39 * Takes @cpu and @hwirq to which the arch-common ISR is hooked up 40 */ 41extern int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq); 42 43/* 44 * struct plat_smp_ops - SMP callbacks provided by platform to ARC SMP 45 * 46 * @info: SoC SMP specific info for /proc/cpuinfo etc 47 * @init_early_smp: A SMP specific h/w block can init itself 48 * Could be common across platforms so not covered by 49 * mach_desc->init_early() 50 * @init_per_cpu: Called for each core so SMP h/w block driver can do 51 * any needed setup per cpu (e.g. IPI request) 52 * @cpu_kick: For Master to kickstart a cpu (optionally at a PC) 53 * @ipi_send: To send IPI to a @cpu 54 * @ips_clear: To clear IPI received at @irq 55 */ 56struct plat_smp_ops { 57 const char *info; 58 void (*init_early_smp)(void); 59 void (*init_per_cpu)(int cpu); 60 void (*cpu_kick)(int cpu, unsigned long pc); 61 void (*ipi_send)(int cpu); 62 void (*ipi_clear)(int irq); 63}; 64 65/* TBD: stop exporting it for direct population by platform */ 66extern struct plat_smp_ops plat_smp_ops; 67 68#else /* CONFIG_SMP */ 69 70static inline void smp_init_cpus(void) {} 71static inline const char *arc_platform_smp_cpuinfo(void) 72{ 73 return ""; 74} 75 76#endif /* !CONFIG_SMP */ 77 78/* 79 * ARC700 doesn't support atomic Read-Modify-Write ops. 80 * Originally Interrupts had to be disabled around code to gaurantee atomicity. 81 * The LLOCK/SCOND insns allow writing interrupt-hassle-free based atomic ops 82 * based on retry-if-irq-in-atomic (with hardware assist). 83 * However despite these, we provide the IRQ disabling variant 84 * 85 * (1) These insn were introduced only in 4.10 release. So for older released 86 * support needed. 87 * 88 * (2) In a SMP setup, the LLOCK/SCOND atomicity across CPUs needs to be 89 * gaurantted by the platform (not something which core handles). 90 * Assuming a platform won't, SMP Linux needs to use spinlocks + local IRQ 91 * disabling for atomicity. 92 * 93 * However exported spinlock API is not usable due to cyclic hdr deps 94 * (even after system.h disintegration upstream) 95 * asm/bitops.h -> linux/spinlock.h -> linux/preempt.h 96 * -> linux/thread_info.h -> linux/bitops.h -> asm/bitops.h 97 * 98 * So the workaround is to use the lowest level arch spinlock API. 99 * The exported spinlock API is smart enough to be NOP for !CONFIG_SMP, 100 * but same is not true for ARCH backend, hence the need for 2 variants 101 */ 102#ifndef CONFIG_ARC_HAS_LLSC 103 104#include <linux/irqflags.h> 105#ifdef CONFIG_SMP 106 107#include <asm/spinlock.h> 108 109extern arch_spinlock_t smp_atomic_ops_lock; 110 111#define atomic_ops_lock(flags) do { \ 112 local_irq_save(flags); \ 113 arch_spin_lock(&smp_atomic_ops_lock); \ 114} while (0) 115 116#define atomic_ops_unlock(flags) do { \ 117 arch_spin_unlock(&smp_atomic_ops_lock); \ 118 local_irq_restore(flags); \ 119} while (0) 120 121#else /* !CONFIG_SMP */ 122 123#define atomic_ops_lock(flags) local_irq_save(flags) 124#define atomic_ops_unlock(flags) local_irq_restore(flags) 125 126#endif /* !CONFIG_SMP */ 127 128#endif /* !CONFIG_ARC_HAS_LLSC */ 129 130#endif 131