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// 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);
}
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