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Diffstat (limited to 'arch/arc/include/asm/smp.h')
| -rw-r--r-- | arch/arc/include/asm/smp.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/arch/arc/include/asm/smp.h b/arch/arc/include/asm/smp.h new file mode 100644 index 000000000..d85649160 --- /dev/null +++ b/arch/arc/include/asm/smp.h @@ -0,0 +1,128 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + */ + +#ifndef __ASM_ARC_SMP_H +#define __ASM_ARC_SMP_H + +#ifdef CONFIG_SMP + +#include <linux/types.h> +#include <linux/init.h> +#include <linux/threads.h> + +#define raw_smp_processor_id() (current_thread_info()->cpu) + +/* including cpumask.h leads to cyclic deps hence this Forward declaration */ +struct cpumask; + +/* + * APIs provided by arch SMP code to generic code + */ +extern void arch_send_call_function_single_ipi(int cpu); +extern void arch_send_call_function_ipi_mask(const struct cpumask *mask); + +/* + * APIs provided by arch SMP code to rest of arch code + */ +extern void __init smp_init_cpus(void); +extern void first_lines_of_secondary(void); +extern const char *arc_platform_smp_cpuinfo(void); + +/* + * API expected BY platform smp code (FROM arch smp code) + * + * smp_ipi_irq_setup: + * Takes @cpu and @hwirq to which the arch-common ISR is hooked up + */ +extern int smp_ipi_irq_setup(int cpu, irq_hw_number_t hwirq); + +/* + * struct plat_smp_ops - SMP callbacks provided by platform to ARC SMP + * + * @info: SoC SMP specific info for /proc/cpuinfo etc + * @init_early_smp: A SMP specific h/w block can init itself + * Could be common across platforms so not covered by + * mach_desc->init_early() + * @init_per_cpu: Called for each core so SMP h/w block driver can do + * any needed setup per cpu (e.g. IPI request) + * @cpu_kick: For Master to kickstart a cpu (optionally at a PC) + * @ipi_send: To send IPI to a @cpu + * @ips_clear: To clear IPI received at @irq + */ +struct plat_smp_ops { + const char *info; + void (*init_early_smp)(void); + void (*init_per_cpu)(int cpu); + void (*cpu_kick)(int cpu, unsigned long pc); + void (*ipi_send)(int cpu); + void (*ipi_clear)(int irq); +}; + +/* TBD: stop exporting it for direct population by platform */ +extern struct plat_smp_ops plat_smp_ops; + +#else /* CONFIG_SMP */ + +static inline void smp_init_cpus(void) {} +static inline const char *arc_platform_smp_cpuinfo(void) +{ + return ""; +} + +#endif /* !CONFIG_SMP */ + +/* + * ARC700 doesn't support atomic Read-Modify-Write ops. + * Originally Interrupts had to be disabled around code to gaurantee atomicity. + * The LLOCK/SCOND insns allow writing interrupt-hassle-free based atomic ops + * based on retry-if-irq-in-atomic (with hardware assist). + * However despite these, we provide the IRQ disabling variant + * + * (1) These insn were introduced only in 4.10 release. So for older released + * support needed. + * + * (2) In a SMP setup, the LLOCK/SCOND atomicity across CPUs needs to be + * gaurantted by the platform (not something which core handles). + * Assuming a platform won't, SMP Linux needs to use spinlocks + local IRQ + * disabling for atomicity. + * + * However exported spinlock API is not usable due to cyclic hdr deps + * (even after system.h disintegration upstream) + * asm/bitops.h -> linux/spinlock.h -> linux/preempt.h + * -> linux/thread_info.h -> linux/bitops.h -> asm/bitops.h + * + * So the workaround is to use the lowest level arch spinlock API. + * The exported spinlock API is smart enough to be NOP for !CONFIG_SMP, + * but same is not true for ARCH backend, hence the need for 2 variants + */ +#ifndef CONFIG_ARC_HAS_LLSC + +#include <linux/irqflags.h> +#ifdef CONFIG_SMP + +#include <asm/spinlock.h> + +extern arch_spinlock_t smp_atomic_ops_lock; + +#define atomic_ops_lock(flags) do { \ + local_irq_save(flags); \ + arch_spin_lock(&smp_atomic_ops_lock); \ +} while (0) + +#define atomic_ops_unlock(flags) do { \ + arch_spin_unlock(&smp_atomic_ops_lock); \ + local_irq_restore(flags); \ +} while (0) + +#else /* !CONFIG_SMP */ + +#define atomic_ops_lock(flags) local_irq_save(flags) +#define atomic_ops_unlock(flags) local_irq_restore(flags) + +#endif /* !CONFIG_SMP */ + +#endif /* !CONFIG_ARC_HAS_LLSC */ + +#endif |