// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2001, 2002, 2003 Broadcom Corporation
 */

#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
#include <linux/sched/task_stack.h>

#include <asm/mmu_context.h>
#include <asm/io.h>
#include <asm/fw/cfe/cfe_api.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>

static void *mailbox_set_regs[] = {
        IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_SET_CPU),
        IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_SET_CPU)
};

static void *mailbox_clear_regs[] = {
        IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_CLR_CPU),
        IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_CLR_CPU)
};

static void *mailbox_regs[] = {
        IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_CPU),
        IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_CPU)
};

/*
 * SMP init and finish on secondary CPUs
 */
void sb1250_smp_init(void)
{
        unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
                STATUSF_IP1 | STATUSF_IP0;

        /* Set interrupt mask, but don't enable */
        change_c0_status(ST0_IM, imask);
}

/*
 * These are routines for dealing with the sb1250 smp capabilities
 * independent of board/firmware
 */

/*
 * Simple enough; everything is set up, so just poke the appropriate mailbox
 * register, and we should be set
 */
static void sb1250_send_ipi_single(int cpu, unsigned int action)
{
        __raw_writeq((((u64)action) << 48), mailbox_set_regs[cpu]);
}

static inline void sb1250_send_ipi_mask(const struct cpumask *mask,
                                        unsigned int action)
{
        unsigned int i;

        for_each_cpu(i, mask)
                sb1250_send_ipi_single(i, action);
}

/*
 * Code to run on secondary just after probing the CPU
 */
static void sb1250_init_secondary(void)
{
        extern void sb1250_smp_init(void);

        sb1250_smp_init();
}

/*
 * Do any tidying up before marking online and running the idle
 * loop
 */
static void sb1250_smp_finish(void)
{
        extern void sb1250_clockevent_init(void);

        sb1250_clockevent_init();
        local_irq_enable();
}

/*
 * Setup the PC, SP, and GP of a secondary processor and start it
 * running!
 */
static int sb1250_boot_secondary(int cpu, struct task_struct *idle)
{
        int retval;

        retval = cfe_cpu_start(cpu_logical_map(cpu), &smp_bootstrap,
                               __KSTK_TOS(idle),
                               (unsigned long)task_thread_info(idle), 0);
        if (retval != 0)
                printk("cfe_start_cpu(%i) returned %i\n" , cpu, retval);
        return retval;
}

/*
 * Use CFE to find out how many CPUs are available, setting up
 * cpu_possible_mask and the logical/physical mappings.
 * XXXKW will the boot CPU ever not be physical 0?
 *
 * Common setup before any secondaries are started
 */
static void __init sb1250_smp_setup(void)
{
        int i, num;

        init_cpu_possible(cpumask_of(0));
        __cpu_number_map[0] = 0;
        __cpu_logical_map[0] = 0;

        for (i = 1, num = 0; i < NR_CPUS; i++) {
                if (cfe_cpu_stop(i) == 0) {
                        set_cpu_possible(i, true);
                        __cpu_number_map[i] = ++num;
                        __cpu_logical_map[num] = i;
                }
        }
        printk(KERN_INFO "Detected %i available secondary CPU(s)\n", num);
}

static void __init sb1250_prepare_cpus(unsigned int max_cpus)
{
}

const struct plat_smp_ops sb_smp_ops = {
        .send_ipi_single        = sb1250_send_ipi_single,
        .send_ipi_mask          = sb1250_send_ipi_mask,
        .init_secondary         = sb1250_init_secondary,
        .smp_finish             = sb1250_smp_finish,
        .boot_secondary         = sb1250_boot_secondary,
        .smp_setup              = sb1250_smp_setup,
        .prepare_cpus           = sb1250_prepare_cpus,
};

void sb1250_mailbox_interrupt(void)
{
        int cpu = smp_processor_id();
        int irq = K_INT_MBOX_0;
        unsigned int action;

        kstat_incr_irq_this_cpu(irq);
        /* Load the mailbox register to figure out what we're supposed to do */
        action = (____raw_readq(mailbox_regs[cpu]) >> 48) & 0xffff;

        /* Clear the mailbox to clear the interrupt */
        ____raw_writeq(((u64)action) << 48, mailbox_clear_regs[cpu]);

        if (action & SMP_RESCHEDULE_YOURSELF)
                scheduler_ipi();

        if (action & SMP_CALL_FUNCTION) {
                irq_enter();
                generic_smp_call_function_interrupt();
                irq_exit();
        }
}