1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #ifndef __ASM_ARC_SMP_H 10 #define __ASM_ARC_SMP_H 11 12 #ifdef CONFIG_SMP 13 14 #include <linux/types.h> 15 #include <linux/init.h> 16 #include <linux/threads.h> 17 18 #define raw_smp_processor_id() (current_thread_info()->cpu) 19 20 /* including cpumask.h leads to cyclic deps hence this Forward declaration */ 21 struct cpumask; 22 23 /* 24 * APIs provided by arch SMP code to generic code 25 */ 26 extern void arch_send_call_function_single_ipi(int cpu); 27 extern void arch_send_call_function_ipi_mask(const struct cpumask *mask); 28 29 /* 30 * APIs provided by arch SMP code to rest of arch code 31 */ 32 extern void __init smp_init_cpus(void); 33 extern void first_lines_of_secondary(void); 34 extern const char *arc_platform_smp_cpuinfo(void); 35 36 /* 37 * API expected BY platform smp code (FROM arch smp code) 38 * 39 * smp_ipi_irq_setup: 40 * Takes @cpu and @irq to which the arch-common ISR is hooked up 41 */ 42 extern int smp_ipi_irq_setup(int cpu, int irq); 43 44 /* 45 * struct plat_smp_ops - SMP callbacks provided by platform to ARC SMP 46 * 47 * @info: SoC SMP specific info for /proc/cpuinfo etc 48 * @cpu_kick: For Master to kickstart a cpu (optionally at a PC) 49 * @ipi_send: To send IPI to a @cpu 50 * @ips_clear: To clear IPI received at @irq 51 */ 52 struct plat_smp_ops { 53 const char *info; 54 void (*cpu_kick)(int cpu, unsigned long pc); 55 void (*ipi_send)(int cpu); 56 void (*ipi_clear)(int irq); 57 }; 58 59 /* TBD: stop exporting it for direct population by platform */ 60 extern struct plat_smp_ops plat_smp_ops; 61 62 #else /* CONFIG_SMP */ 63 64 static inline void smp_init_cpus(void) {} 65 static inline const char *arc_platform_smp_cpuinfo(void) 66 { 67 return ""; 68 } 69 70 #endif /* !CONFIG_SMP */ 71 72 /* 73 * ARC700 doesn't support atomic Read-Modify-Write ops. 74 * Originally Interrupts had to be disabled around code to gaurantee atomicity. 75 * The LLOCK/SCOND insns allow writing interrupt-hassle-free based atomic ops 76 * based on retry-if-irq-in-atomic (with hardware assist). 77 * However despite these, we provide the IRQ disabling variant 78 * 79 * (1) These insn were introduced only in 4.10 release. So for older released 80 * support needed. 81 * 82 * (2) In a SMP setup, the LLOCK/SCOND atomiticity across CPUs needs to be 83 * gaurantted by the platform (not something which core handles). 84 * Assuming a platform won't, SMP Linux needs to use spinlocks + local IRQ 85 * disabling for atomicity. 86 * 87 * However exported spinlock API is not usable due to cyclic hdr deps 88 * (even after system.h disintegration upstream) 89 * asm/bitops.h -> linux/spinlock.h -> linux/preempt.h 90 * -> linux/thread_info.h -> linux/bitops.h -> asm/bitops.h 91 * 92 * So the workaround is to use the lowest level arch spinlock API. 93 * The exported spinlock API is smart enough to be NOP for !CONFIG_SMP, 94 * but same is not true for ARCH backend, hence the need for 2 variants 95 */ 96 #ifndef CONFIG_ARC_HAS_LLSC 97 98 #include <linux/irqflags.h> 99 #ifdef CONFIG_SMP 100 101 #include <asm/spinlock.h> 102 103 extern arch_spinlock_t smp_atomic_ops_lock; 104 extern arch_spinlock_t smp_bitops_lock; 105 106 #define atomic_ops_lock(flags) do { \ 107 local_irq_save(flags); \ 108 arch_spin_lock(&smp_atomic_ops_lock); \ 109 } while (0) 110 111 #define atomic_ops_unlock(flags) do { \ 112 arch_spin_unlock(&smp_atomic_ops_lock); \ 113 local_irq_restore(flags); \ 114 } while (0) 115 116 #define bitops_lock(flags) do { \ 117 local_irq_save(flags); \ 118 arch_spin_lock(&smp_bitops_lock); \ 119 } while (0) 120 121 #define bitops_unlock(flags) do { \ 122 arch_spin_unlock(&smp_bitops_lock); \ 123 local_irq_restore(flags); \ 124 } while (0) 125 126 #else /* !CONFIG_SMP */ 127 128 #define atomic_ops_lock(flags) local_irq_save(flags) 129 #define atomic_ops_unlock(flags) local_irq_restore(flags) 130 131 #define bitops_lock(flags) local_irq_save(flags) 132 #define bitops_unlock(flags) local_irq_restore(flags) 133 134 #endif /* !CONFIG_SMP */ 135 136 #endif /* !CONFIG_ARC_HAS_LLSC */ 137 138 #endif 139