diff options
Diffstat (limited to 'arch/hexagon/kernel/smp.c')
| -rw-r--r-- | arch/hexagon/kernel/smp.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/arch/hexagon/kernel/smp.c b/arch/hexagon/kernel/smp.c new file mode 100644 index 0000000000..4e8bee25b8 --- /dev/null +++ b/arch/hexagon/kernel/smp.c @@ -0,0 +1,249 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * SMP support for Hexagon + * + * Copyright (c) 2010-2012, The Linux Foundation. All rights reserved. + */ + +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/percpu.h> +#include <linux/sched/mm.h> +#include <linux/smp.h> +#include <linux/spinlock.h> +#include <linux/cpu.h> +#include <linux/mm_types.h> + +#include <asm/time.h> /* timer_interrupt */ +#include <asm/hexagon_vm.h> + +#define BASE_IPI_IRQ 26 + +/* + * cpu_possible_mask needs to be filled out prior to setup_per_cpu_areas + * (which is prior to any of our smp_prepare_cpu crap), in order to set + * up the... per_cpu areas. + */ + +struct ipi_data { + unsigned long bits; +}; + +static DEFINE_PER_CPU(struct ipi_data, ipi_data); + +static inline void __handle_ipi(unsigned long *ops, struct ipi_data *ipi, + int cpu) +{ + unsigned long msg = 0; + do { + msg = find_next_bit(ops, BITS_PER_LONG, msg+1); + + switch (msg) { + + case IPI_TIMER: + ipi_timer(); + break; + + case IPI_CALL_FUNC: + generic_smp_call_function_interrupt(); + break; + + case IPI_CPU_STOP: + /* + * call vmstop() + */ + __vmstop(); + break; + + case IPI_RESCHEDULE: + scheduler_ipi(); + break; + } + } while (msg < BITS_PER_LONG); +} + +/* Used for IPI call from other CPU's to unmask int */ +void smp_vm_unmask_irq(void *info) +{ + __vmintop_locen((long) info); +} + + +/* + * This is based on Alpha's IPI stuff. + * Supposed to take (int, void*) as args now. + * Specifically, first arg is irq, second is the irq_desc. + */ + +irqreturn_t handle_ipi(int irq, void *desc) +{ + int cpu = smp_processor_id(); + struct ipi_data *ipi = &per_cpu(ipi_data, cpu); + unsigned long ops; + + while ((ops = xchg(&ipi->bits, 0)) != 0) + __handle_ipi(&ops, ipi, cpu); + return IRQ_HANDLED; +} + +void send_ipi(const struct cpumask *cpumask, enum ipi_message_type msg) +{ + unsigned long flags; + unsigned long cpu; + unsigned long retval; + + local_irq_save(flags); + + for_each_cpu(cpu, cpumask) { + struct ipi_data *ipi = &per_cpu(ipi_data, cpu); + + set_bit(msg, &ipi->bits); + /* Possible barrier here */ + retval = __vmintop_post(BASE_IPI_IRQ+cpu); + + if (retval != 0) { + printk(KERN_ERR "interrupt %ld not configured?\n", + BASE_IPI_IRQ+cpu); + } + } + + local_irq_restore(flags); +} + +void __init smp_prepare_boot_cpu(void) +{ +} + +/* + * interrupts should already be disabled from the VM + * SP should already be correct; need to set THREADINFO_REG + * to point to current thread info + */ + +void start_secondary(void) +{ + unsigned long thread_ptr; + unsigned int cpu, irq; + + /* Calculate thread_info pointer from stack pointer */ + __asm__ __volatile__( + "%0 = SP;\n" + : "=r" (thread_ptr) + ); + + thread_ptr = thread_ptr & ~(THREAD_SIZE-1); + + __asm__ __volatile__( + QUOTED_THREADINFO_REG " = %0;\n" + : + : "r" (thread_ptr) + ); + + /* Set the memory struct */ + mmgrab(&init_mm); + current->active_mm = &init_mm; + + cpu = smp_processor_id(); + + irq = BASE_IPI_IRQ + cpu; + if (request_irq(irq, handle_ipi, IRQF_TRIGGER_RISING, "ipi_handler", + NULL)) + pr_err("Failed to request irq %u (ipi_handler)\n", irq); + + /* Register the clock_event dummy */ + setup_percpu_clockdev(); + + printk(KERN_INFO "%s cpu %d\n", __func__, current_thread_info()->cpu); + + notify_cpu_starting(cpu); + + set_cpu_online(cpu, true); + + local_irq_enable(); + + cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); +} + + +/* + * called once for each present cpu + * apparently starts up the CPU and then + * maintains control until "cpu_online(cpu)" is set. + */ + +int __cpu_up(unsigned int cpu, struct task_struct *idle) +{ + struct thread_info *thread = (struct thread_info *)idle->stack; + void *stack_start; + + thread->cpu = cpu; + + /* Boot to the head. */ + stack_start = ((void *) thread) + THREAD_SIZE; + __vmstart(start_secondary, stack_start); + + while (!cpu_online(cpu)) + barrier(); + + return 0; +} + +void __init smp_cpus_done(unsigned int max_cpus) +{ +} + +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + int i, irq = BASE_IPI_IRQ; + + /* + * should eventually have some sort of machine + * descriptor that has this stuff + */ + + /* Right now, let's just fake it. */ + for (i = 0; i < max_cpus; i++) + set_cpu_present(i, true); + + /* Also need to register the interrupts for IPI */ + if (max_cpus > 1) { + if (request_irq(irq, handle_ipi, IRQF_TRIGGER_RISING, + "ipi_handler", NULL)) + pr_err("Failed to request irq %d (ipi_handler)\n", irq); + } +} + +void arch_smp_send_reschedule(int cpu) +{ + send_ipi(cpumask_of(cpu), IPI_RESCHEDULE); +} + +void smp_send_stop(void) +{ + struct cpumask targets; + cpumask_copy(&targets, cpu_online_mask); + cpumask_clear_cpu(smp_processor_id(), &targets); + send_ipi(&targets, IPI_CPU_STOP); +} + +void arch_send_call_function_single_ipi(int cpu) +{ + send_ipi(cpumask_of(cpu), IPI_CALL_FUNC); +} + +void arch_send_call_function_ipi_mask(const struct cpumask *mask) +{ + send_ipi(mask, IPI_CALL_FUNC); +} + +void smp_start_cpus(void) +{ + int i; + + for (i = 0; i < NR_CPUS; i++) + set_cpu_possible(i, true); +} |