Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * SMP support for BPA machines.
 *
 * Dave Engebretsen, Peter Bergner, and
 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
 *
 * Plus various changes from other IBM teams...
 */
 
#undef DEBUG
 
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/cpu.h>
#include <linux/pgtable.h>
 
#include <asm/ptrace.h>
#include <linux/atomic.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/paca.h>
#include <asm/machdep.h>
#include <asm/cputable.h>
#include <asm/firmware.h>
#include <asm/rtas.h>
#include <asm/cputhreads.h>
#include <asm/code-patching.h>
 
#include "interrupt.h"
#include <asm/udbg.h>
 
#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
 
/*
 * The Primary thread of each non-boot processor was started from the OF client
 * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
 */
static cpumask_t of_spin_map;
 
/**
 * smp_startup_cpu() - start the given cpu
 *
 * At boot time, there is nothing to do for primary threads which were
 * started from Open Firmware.  For anything else, call RTAS with the
 * appropriate start location.
 *
 * Returns:
 *	0	- failure
 *	1	- success
 */
static inline int smp_startup_cpu(unsigned int lcpu)
{
<------>int status;
<------>unsigned long start_here =
<------><------><------>__pa(ppc_function_entry(generic_secondary_smp_init));
<------>unsigned int pcpu;
<------>int start_cpu;
 
<------>if (cpumask_test_cpu(lcpu, &of_spin_map))
<------><------>/* Already started by OF and sitting in spin loop */
<------><------>return 1;
 
<------>pcpu = get_hard_smp_processor_id(lcpu);
 
<------>/*
<------> * If the RTAS start-cpu token does not exist then presume the
<------> * cpu is already spinning.
<------> */
<------>start_cpu = rtas_token("start-cpu");
<------>if (start_cpu == RTAS_UNKNOWN_SERVICE)
<------><------>return 1;
 
<------>status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, lcpu);
<------>if (status != 0) {
<------><------>printk(KERN_ERR "start-cpu failed: %i\n", status);
<------><------>return 0;
<------>}
 
<------>return 1;
}
 
static void smp_cell_setup_cpu(int cpu)
{
<------>if (cpu != boot_cpuid)
<------><------>iic_setup_cpu();
 
<------>/*
<------> * change default DABRX to allow user watchpoints
<------> */
<------>mtspr(SPRN_DABRX, DABRX_KERNEL | DABRX_USER);
}
 
static int smp_cell_kick_cpu(int nr)
{
<------>if (nr < 0 || nr >= nr_cpu_ids)
<------><------>return -EINVAL;
 
<------>if (!smp_startup_cpu(nr))
<------><------>return -ENOENT;
 
<------>/*
<------> * The processor is currently spinning, waiting for the
<------> * cpu_start field to become non-zero After we set cpu_start,
<------> * the processor will continue on to secondary_start
<------> */
<------>paca_ptrs[nr]->cpu_start = 1;
 
<------>return 0;
}
 
static struct smp_ops_t bpa_iic_smp_ops = {
<------>.message_pass	= iic_message_pass,
<------>.probe		= iic_request_IPIs,
<------>.kick_cpu	= smp_cell_kick_cpu,
<------>.setup_cpu	= smp_cell_setup_cpu,
<------>.cpu_bootable	= smp_generic_cpu_bootable,
};
 
/* This is called very early */
void __init smp_init_cell(void)
{
<------>int i;
 
<------>DBG(" -> smp_init_cell()\n");
 
<------>smp_ops = &bpa_iic_smp_ops;
 
<------>/* Mark threads which are still spinning in hold loops. */
<------>if (cpu_has_feature(CPU_FTR_SMT)) {
<------><------>for_each_present_cpu(i) {
<------><------><------>if (cpu_thread_in_core(i) == 0)
<------><------><------><------>cpumask_set_cpu(i, &of_spin_map);
<------><------>}
<------>} else
<------><------>cpumask_copy(&of_spin_map, cpu_present_mask);
 
<------>cpumask_clear_cpu(boot_cpuid, &of_spin_map);
 
<------>/* Non-lpar has additional take/give timebase */
<------>if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
<------><------>smp_ops->give_timebase = rtas_give_timebase;
<------><------>smp_ops->take_timebase = rtas_take_timebase;
<------>}
 
<------>DBG(" <- smp_init_cell()\n");
}