// SPDX-License-Identifier: GPL-2.0
/* Sparc SS1000/SC2000 SMP support.
 *
 * Copyright (C) 1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 *
 * Based on sun4m's smp.c, which is:
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 */

#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/profile.h>
#include <linux/delay.h>
#include <linux/sched/mm.h>
#include <linux/cpu.h>

#include <asm/cacheflush.h>
#include <asm/switch_to.h>
#include <asm/tlbflush.h>
#include <asm/timer.h>
#include <asm/oplib.h>
#include <asm/sbi.h>
#include <asm/mmu.h>

#include "kernel.h"
#include "irq.h"

#define IRQ_CROSS_CALL          15

static volatile int smp_processors_ready;
static int smp_highest_cpu;

static inline unsigned long sun4d_swap(volatile unsigned long *ptr, unsigned long val)
{
        __asm__ __volatile__("swap [%1], %0\n\t" :
                             "=&r" (val), "=&r" (ptr) :
                             "0" (val), "1" (ptr));
        return val;
}

static void smp4d_ipi_init(void);

static unsigned char cpu_leds[32];

static inline void show_leds(int cpuid)
{
        cpuid &= 0x1e;
        __asm__ __volatile__ ("stba %0, [%1] %2" : :
                              "r" ((cpu_leds[cpuid] << 4) | cpu_leds[cpuid+1]),
                              "r" (ECSR_BASE(cpuid) | BB_LEDS),
                              "i" (ASI_M_CTL));
}

void sun4d_cpu_pre_starting(void *arg)
{
        int cpuid = hard_smp_processor_id();

        /* Show we are alive */
        cpu_leds[cpuid] = 0x6;
        show_leds(cpuid);

        /* Enable level15 interrupt, disable level14 interrupt for now */
        cc_set_imsk((cc_get_imsk() & ~0x8000) | 0x4000);
}

void sun4d_cpu_pre_online(void *arg)
{
        unsigned long flags;
        int cpuid;

        cpuid = hard_smp_processor_id();

        /* Unblock the master CPU _only_ when the scheduler state
         * of all secondary CPUs will be up-to-date, so after
         * the SMP initialization the master will be just allowed
         * to call the scheduler code.
         */
        sun4d_swap((unsigned long *)&cpu_callin_map[cpuid], 1);
        local_ops->cache_all();
        local_ops->tlb_all();

        while ((unsigned long)current_set[cpuid] < PAGE_OFFSET)
                barrier();

        while (current_set[cpuid]->cpu != cpuid)
                barrier();

        /* Fix idle thread fields. */
        __asm__ __volatile__("ld [%0], %%g6\n\t"
                             : : "r" (&current_set[cpuid])
                             : "memory" /* paranoid */);

        cpu_leds[cpuid] = 0x9;
        show_leds(cpuid);

        /* Attach to the address space of init_task. */
        mmgrab(&init_mm);
        current->active_mm = &init_mm;

        local_ops->cache_all();
        local_ops->tlb_all();

        while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
                barrier();

        spin_lock_irqsave(&sun4d_imsk_lock, flags);
        cc_set_imsk(cc_get_imsk() & ~0x4000); /* Allow PIL 14 as well */
        spin_unlock_irqrestore(&sun4d_imsk_lock, flags);
}

/*
 *      Cycle through the processors asking the PROM to start each one.
 */
void __init smp4d_boot_cpus(void)
{
        smp4d_ipi_init();
        if (boot_cpu_id)
                current_set[0] = NULL;
        local_ops->cache_all();
}

int smp4d_boot_one_cpu(int i, struct task_struct *idle)
{
        unsigned long *entry = &sun4d_cpu_startup;
        int timeout;
        int cpu_node;

        cpu_find_by_instance(i, &cpu_node, NULL);
        current_set[i] = task_thread_info(idle);
        /*
         * Initialize the contexts table
         * Since the call to prom_startcpu() trashes the structure,
         * we need to re-initialize it for each cpu
         */
        smp_penguin_ctable.which_io = 0;
        smp_penguin_ctable.phys_addr = (unsigned int) srmmu_ctx_table_phys;
        smp_penguin_ctable.reg_size = 0;

        /* whirrr, whirrr, whirrrrrrrrr... */
        printk(KERN_INFO "Starting CPU %d at %p\n", i, entry);
        local_ops->cache_all();
        prom_startcpu(cpu_node,
                      &smp_penguin_ctable, 0, (char *)entry);

        printk(KERN_INFO "prom_startcpu returned :)\n");

        /* wheee... it's going... */
        for (timeout = 0; timeout < 10000; timeout++) {
                if (cpu_callin_map[i])
                        break;
                udelay(200);
        }

        if (!(cpu_callin_map[i])) {
                printk(KERN_ERR "Processor %d is stuck.\n", i);
                return -ENODEV;

        }
        local_ops->cache_all();
        return 0;
}

void __init smp4d_smp_done(void)
{
        int i, first;
        int *prev;

        /* setup cpu list for irq rotation */
        first = 0;
        prev = &first;
        for_each_online_cpu(i) {
                *prev = i;
                prev = &cpu_data(i).next;
        }
        *prev = first;
        local_ops->cache_all();

        /* Ok, they are spinning and ready to go. */
        smp_processors_ready = 1;
        sun4d_distribute_irqs();
}

/* Memory structure giving interrupt handler information about IPI generated */
struct sun4d_ipi_work {
        int single;
        int msk;
        int resched;
};

static DEFINE_PER_CPU_SHARED_ALIGNED(struct sun4d_ipi_work, sun4d_ipi_work);

/* Initialize IPIs on the SUN4D SMP machine */
static void __init smp4d_ipi_init(void)
{
        int cpu;
        struct sun4d_ipi_work *work;

        printk(KERN_INFO "smp4d: setup IPI at IRQ %d\n", SUN4D_IPI_IRQ);

        for_each_possible_cpu(cpu) {
                work = &per_cpu(sun4d_ipi_work, cpu);
                work->single = work->msk = work->resched = 0;
        }
}

void sun4d_ipi_interrupt(void)
{
        struct sun4d_ipi_work *work = this_cpu_ptr(&sun4d_ipi_work);

        if (work->single) {
                work->single = 0;
                smp_call_function_single_interrupt();
        }
        if (work->msk) {
                work->msk = 0;
                smp_call_function_interrupt();
        }
        if (work->resched) {
                work->resched = 0;
                smp_resched_interrupt();
        }
}

/* +-------+-------------+-----------+------------------------------------+
 * | bcast |  devid      |   sid     |              levels mask           |
 * +-------+-------------+-----------+------------------------------------+
 *  31      30         23 22       15 14                                 0
 */
#define IGEN_MESSAGE(bcast, devid, sid, levels) \
        (((bcast) << 31) | ((devid) << 23) | ((sid) << 15) | (levels))

static void sun4d_send_ipi(int cpu, int level)
{
        cc_set_igen(IGEN_MESSAGE(0, cpu << 3, 6 + ((level >> 1) & 7), 1 << (level - 1)));
}

static void sun4d_ipi_single(int cpu)
{
        struct sun4d_ipi_work *work = &per_cpu(sun4d_ipi_work, cpu);

        /* Mark work */
        work->single = 1;

        /* Generate IRQ on the CPU */
        sun4d_send_ipi(cpu, SUN4D_IPI_IRQ);
}

static void sun4d_ipi_mask_one(int cpu)
{
        struct sun4d_ipi_work *work = &per_cpu(sun4d_ipi_work, cpu);

        /* Mark work */
        work->msk = 1;

        /* Generate IRQ on the CPU */
        sun4d_send_ipi(cpu, SUN4D_IPI_IRQ);
}

static void sun4d_ipi_resched(int cpu)
{
        struct sun4d_ipi_work *work = &per_cpu(sun4d_ipi_work, cpu);

        /* Mark work */
        work->resched = 1;

        /* Generate IRQ on the CPU (any IRQ will cause resched) */
        sun4d_send_ipi(cpu, SUN4D_IPI_IRQ);
}

static struct smp_funcall {
        smpfunc_t func;
        unsigned long arg1;
        unsigned long arg2;
        unsigned long arg3;
        unsigned long arg4;
        unsigned long arg5;
        unsigned char processors_in[NR_CPUS];  /* Set when ipi entered. */
        unsigned char processors_out[NR_CPUS]; /* Set when ipi exited. */
} ccall_info __attribute__((aligned(8)));

static DEFINE_SPINLOCK(cross_call_lock);

/* Cross calls must be serialized, at least currently. */
static void sun4d_cross_call(smpfunc_t func, cpumask_t mask, unsigned long arg1,
                             unsigned long arg2, unsigned long arg3,
                             unsigned long arg4)
{
        if (smp_processors_ready) {
                register int high = smp_highest_cpu;
                unsigned long flags;

                spin_lock_irqsave(&cross_call_lock, flags);

                {
                        /*
                         * If you make changes here, make sure
                         * gcc generates proper code...
                         */
                        register smpfunc_t f asm("i0") = func;
                        register unsigned long a1 asm("i1") = arg1;
                        register unsigned long a2 asm("i2") = arg2;
                        register unsigned long a3 asm("i3") = arg3;
                        register unsigned long a4 asm("i4") = arg4;
                        register unsigned long a5 asm("i5") = 0;

                        __asm__ __volatile__(
                                "std %0, [%6]\n\t"
                                "std %2, [%6 + 8]\n\t"
                                "std %4, [%6 + 16]\n\t" : :
                                "r"(f), "r"(a1), "r"(a2), "r"(a3), "r"(a4), "r"(a5),
                                "r" (&ccall_info.func));
                }

                /* Init receive/complete mapping, plus fire the IPI's off. */
                {
                        register int i;

                        cpumask_clear_cpu(smp_processor_id(), &mask);
                        cpumask_and(&mask, cpu_online_mask, &mask);
                        for (i = 0; i <= high; i++) {
                                if (cpumask_test_cpu(i, &mask)) {
                                        ccall_info.processors_in[i] = 0;
                                        ccall_info.processors_out[i] = 0;
                                        sun4d_send_ipi(i, IRQ_CROSS_CALL);
                                }
                        }
                }

                {
                        register int i;

                        i = 0;
                        do {
                                if (!cpumask_test_cpu(i, &mask))
                                        continue;
                                while (!ccall_info.processors_in[i])
                                        barrier();
                        } while (++i <= high);

                        i = 0;
                        do {
                                if (!cpumask_test_cpu(i, &mask))
                                        continue;
                                while (!ccall_info.processors_out[i])
                                        barrier();
                        } while (++i <= high);
                }

                spin_unlock_irqrestore(&cross_call_lock, flags);
        }
}

/* Running cross calls. */
void smp4d_cross_call_irq(void)
{
        int i = hard_smp_processor_id();

        ccall_info.processors_in[i] = 1;
        ccall_info.func(ccall_info.arg1, ccall_info.arg2, ccall_info.arg3,
                        ccall_info.arg4, ccall_info.arg5);
        ccall_info.processors_out[i] = 1;
}

void smp4d_percpu_timer_interrupt(struct pt_regs *regs)
{
        struct pt_regs *old_regs;
        int cpu = hard_smp_processor_id();
        struct clock_event_device *ce;
        static int cpu_tick[NR_CPUS];
        static char led_mask[] = { 0xe, 0xd, 0xb, 0x7, 0xb, 0xd };

        old_regs = set_irq_regs(regs);
        bw_get_prof_limit(cpu);
        bw_clear_intr_mask(0, 1);       /* INTR_TABLE[0] & 1 is Profile IRQ */

        cpu_tick[cpu]++;
        if (!(cpu_tick[cpu] & 15)) {
                if (cpu_tick[cpu] == 0x60)
                        cpu_tick[cpu] = 0;
                cpu_leds[cpu] = led_mask[cpu_tick[cpu] >> 4];
                show_leds(cpu);
        }

        ce = &per_cpu(sparc32_clockevent, cpu);

        irq_enter();
        ce->event_handler(ce);
        irq_exit();

        set_irq_regs(old_regs);
}

static const struct sparc32_ipi_ops sun4d_ipi_ops = {
        .cross_call = sun4d_cross_call,
        .resched    = sun4d_ipi_resched,
        .single     = sun4d_ipi_single,
        .mask_one   = sun4d_ipi_mask_one,
};

void __init sun4d_init_smp(void)
{
        int i;

        /* Patch ipi15 trap table */
        t_nmi[1] = t_nmi[1] + (linux_trap_ipi15_sun4d - linux_trap_ipi15_sun4m);

        sparc32_ipi_ops = &sun4d_ipi_ops;

        for (i = 0; i < NR_CPUS; i++) {
                ccall_info.processors_in[i] = 1;
                ccall_info.processors_out[i] = 1;
        }
}