| /* Copyright (c) 2022 Intel corporation |
| * SPDX-License-Identifier: Apache-2.0 |
| */ |
| |
| #include <zephyr/kernel.h> |
| #include <zephyr/kernel_structs.h> |
| #include <zephyr/spinlock.h> |
| #include <kswap.h> |
| #include <kernel_internal.h> |
| |
| static atomic_t global_lock; |
| static atomic_t cpu_start_flag; |
| static atomic_t ready_flag; |
| |
| unsigned int z_smp_global_lock(void) |
| { |
| unsigned int key = arch_irq_lock(); |
| |
| if (!_current->base.global_lock_count) { |
| while (!atomic_cas(&global_lock, 0, 1)) { |
| } |
| } |
| |
| _current->base.global_lock_count++; |
| |
| return key; |
| } |
| |
| void z_smp_global_unlock(unsigned int key) |
| { |
| if (_current->base.global_lock_count != 0U) { |
| _current->base.global_lock_count--; |
| |
| if (!_current->base.global_lock_count) { |
| atomic_clear(&global_lock); |
| } |
| } |
| |
| arch_irq_unlock(key); |
| } |
| |
| /* Called from within z_swap(), so assumes lock already held */ |
| void z_smp_release_global_lock(struct k_thread *thread) |
| { |
| if (!thread->base.global_lock_count) { |
| atomic_clear(&global_lock); |
| } |
| } |
| |
| /* Tiny delay that relaxes bus traffic to avoid spamming a shared |
| * memory bus looking at an atomic variable |
| */ |
| static inline void local_delay(void) |
| { |
| for (volatile int i = 0; i < 1000; i++) { |
| } |
| } |
| |
| static void wait_for_start_signal(atomic_t *start_flag) |
| { |
| /* Wait for the signal to begin scheduling */ |
| while (!atomic_get(start_flag)) { |
| local_delay(); |
| } |
| } |
| |
| /* Legacy interfaces for early-version SOF CPU bringup. To be removed */ |
| #ifdef CONFIG_SOF |
| void z_smp_thread_init(void *arg, struct k_thread *thread) |
| { |
| z_dummy_thread_init(thread); |
| wait_for_start_signal(arg); |
| } |
| void z_smp_thread_swap(void) |
| { |
| z_swap_unlocked(); |
| } |
| #endif |
| |
| static inline FUNC_NORETURN void smp_init_top(void *arg) |
| { |
| struct k_thread dummy_thread; |
| |
| (void)atomic_set(&ready_flag, 1); |
| |
| wait_for_start_signal(arg); |
| z_dummy_thread_init(&dummy_thread); |
| #ifdef CONFIG_SYS_CLOCK_EXISTS |
| smp_timer_init(); |
| #endif |
| |
| z_swap_unlocked(); |
| |
| CODE_UNREACHABLE; /* LCOV_EXCL_LINE */ |
| } |
| |
| static void start_cpu(int id, atomic_t *start_flag) |
| { |
| z_init_cpu(id); |
| (void)atomic_clear(&ready_flag); |
| arch_start_cpu(id, z_interrupt_stacks[id], CONFIG_ISR_STACK_SIZE, |
| smp_init_top, start_flag); |
| while (!atomic_get(&ready_flag)) { |
| local_delay(); |
| } |
| } |
| |
| void z_smp_start_cpu(int id) |
| { |
| (void)atomic_set(&cpu_start_flag, 1); /* async, don't care */ |
| start_cpu(id, &cpu_start_flag); |
| } |
| |
| void z_smp_init(void) |
| { |
| (void)atomic_clear(&cpu_start_flag); |
| |
| unsigned int num_cpus = arch_num_cpus(); |
| |
| for (int i = 1; i < num_cpus; i++) { |
| start_cpu(i, &cpu_start_flag); |
| } |
| (void)atomic_set(&cpu_start_flag, 1); |
| } |
| |
| bool z_smp_cpu_mobile(void) |
| { |
| unsigned int k = arch_irq_lock(); |
| bool pinned = arch_is_in_isr() || !arch_irq_unlocked(k); |
| |
| arch_irq_unlock(k); |
| return !pinned; |
| } |