// SPDX-License-Identifier: GPL-2.0
/* leon_smp.c: Sparc-Leon SMP support.
 *
 * based on sun4m_smp.c
 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 2009 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB
 * Copyright (C) 2009 Konrad Eisele (konrad@gaisler.com) Aeroflex Gaisler AB
 */

#include <asm/head.h>

#include <linux/kernel.h>
#include <linux/sched/mm.h>
#include <linux/threads.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/of.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/profile.h>
#include <linux/pm.h>
#include <linux/delay.h>
#include <linux/gfp.h>
#include <linux/cpu.h>
#include <linux/clockchips.h>

#include <asm/cacheflush.h>
#include <asm/tlbflush.h>

#include <asm/ptrace.h>
#include <linux/atomic.h>
#include <asm/irq_regs.h>
#include <asm/traps.h>

#include <asm/delay.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/oplib.h>
#include <asm/cpudata.h>
#include <asm/asi.h>
#include <asm/leon.h>
#include <asm/leon_amba.h>
#include <asm/timer.h>

#include "kernel.h"

#include "irq.h"

extern ctxd_t *srmmu_ctx_table_phys;
static int smp_processors_ready;
extern volatile unsigned long cpu_callin_map[NR_CPUS];
extern cpumask_t smp_commenced_mask;
void leon_configure_cache_smp(void);
static void leon_ipi_init(void);

/* IRQ number of LEON IPIs */
int leon_ipi_irq = LEON3_IRQ_IPI_DEFAULT;

static inline unsigned long do_swap(volatile unsigned long *ptr,
                                    unsigned long val)
{
        __asm__ __volatile__("swapa [%2] %3, %0\n\t" : "=&r"(val)
                             : "0"(val), "r"(ptr), "i"(ASI_LEON_DCACHE_MISS)
                             : "memory");
        return val;
}

void leon_cpu_pre_starting(void *arg)
{
        leon_configure_cache_smp();
}

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

        /* Allow master to continue. The master will then give us the
         * go-ahead by setting the smp_commenced_mask and will wait without
         * timeouts until our setup is completed fully (signified by
         * our bit being set in the cpu_online_mask).
         */
        do_swap(&cpu_callin_map[cpuid], 1);

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

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

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

        while (!cpumask_test_cpu(cpuid, &smp_commenced_mask))
                mb();
}

/*
 *      Cycle through the processors asking the PROM to start each one.
 */

extern struct linux_prom_registers smp_penguin_ctable;

void leon_configure_cache_smp(void)
{
        unsigned long cfg = sparc_leon3_get_dcachecfg();
        int me = smp_processor_id();

        if (ASI_LEON3_SYSCTRL_CFG_SSIZE(cfg) > 4) {
                printk(KERN_INFO "Note: SMP with snooping only works on 4k cache, found %dk(0x%x) on cpu %d, disabling caches\n",
                     (unsigned int)ASI_LEON3_SYSCTRL_CFG_SSIZE(cfg),
                     (unsigned int)cfg, (unsigned int)me);
                sparc_leon3_disable_cache();
        } else {
                if (cfg & ASI_LEON3_SYSCTRL_CFG_SNOOPING) {
                        sparc_leon3_enable_snooping();
                } else {
                        printk(KERN_INFO "Note: You have to enable snooping in the vhdl model cpu %d, disabling caches\n",
                             me);
                        sparc_leon3_disable_cache();
                }
        }

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

static void leon_smp_setbroadcast(unsigned int mask)
{
        int broadcast =
            ((LEON3_BYPASS_LOAD_PA(&(leon3_irqctrl_regs->mpstatus)) >>
              LEON3_IRQMPSTATUS_BROADCAST) & 1);
        if (!broadcast) {
                prom_printf("######## !!!! The irqmp-ctrl must have broadcast enabled, smp wont work !!!!! ####### nr cpus: %d\n",
                     leon_smp_nrcpus());
                if (leon_smp_nrcpus() > 1) {
                        BUG();
                } else {
                        prom_printf("continue anyway\n");
                        return;
                }
        }
        LEON_BYPASS_STORE_PA(&(leon3_irqctrl_regs->mpbroadcast), mask);
}

int leon_smp_nrcpus(void)
{
        int nrcpu =
            ((LEON3_BYPASS_LOAD_PA(&(leon3_irqctrl_regs->mpstatus)) >>
              LEON3_IRQMPSTATUS_CPUNR) & 0xf) + 1;
        return nrcpu;
}

void __init leon_boot_cpus(void)
{
        int nrcpu = leon_smp_nrcpus();
        int me = smp_processor_id();

        /* Setup IPI */
        leon_ipi_init();

        printk(KERN_INFO "%d:(%d:%d) cpus mpirq at 0x%x\n", (unsigned int)me,
               (unsigned int)nrcpu, (unsigned int)NR_CPUS,
               (unsigned int)&(leon3_irqctrl_regs->mpstatus));

        leon_enable_irq_cpu(LEON3_IRQ_CROSS_CALL, me);
        leon_enable_irq_cpu(LEON3_IRQ_TICKER, me);
        leon_enable_irq_cpu(leon_ipi_irq, me);

        leon_smp_setbroadcast(1 << LEON3_IRQ_TICKER);

        leon_configure_cache_smp();
        local_ops->cache_all();

}

int leon_boot_one_cpu(int i, struct task_struct *idle)
{
        int timeout;

        current_set[i] = task_thread_info(idle);

        /* See trampoline.S:leon_smp_cpu_startup for details...
         * 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 : (irqmp: 0x%x)\n", (unsigned int)i,
               (unsigned int)&leon3_irqctrl_regs->mpstatus);
        local_ops->cache_all();

        /* Make sure all IRQs are of from the start for this new CPU */
        LEON_BYPASS_STORE_PA(&leon3_irqctrl_regs->mask[i], 0);

        /* Wake one CPU */
        LEON_BYPASS_STORE_PA(&(leon3_irqctrl_regs->mpstatus), 1 << i);

        /* wheee... it's going... */
        for (timeout = 0; timeout < 10000; timeout++) {
                if (cpu_callin_map[i])
                        break;
                udelay(200);
        }
        printk(KERN_INFO "Started CPU %d\n", (unsigned int)i);

        if (!(cpu_callin_map[i])) {
                printk(KERN_ERR "Processor %d is stuck.\n", i);
                return -ENODEV;
        } else {
                leon_enable_irq_cpu(LEON3_IRQ_CROSS_CALL, i);
                leon_enable_irq_cpu(LEON3_IRQ_TICKER, i);
                leon_enable_irq_cpu(leon_ipi_irq, i);
        }

        local_ops->cache_all();
        return 0;
}

void __init leon_smp_done(void)
{

        int i, first;
        int *prev;

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

        /* Free unneeded trap tables */
        if (!cpu_present(1)) {
                free_reserved_page(virt_to_page(&trapbase_cpu1));
        }
        if (!cpu_present(2)) {
                free_reserved_page(virt_to_page(&trapbase_cpu2));
        }
        if (!cpu_present(3)) {
                free_reserved_page(virt_to_page(&trapbase_cpu3));
        }
        /* Ok, they are spinning and ready to go. */
        smp_processors_ready = 1;

}

struct leon_ipi_work {
        int single;
        int msk;
        int resched;
};

static DEFINE_PER_CPU_SHARED_ALIGNED(struct leon_ipi_work, leon_ipi_work);

/* Initialize IPIs on the LEON, in order to save IRQ resources only one IRQ
 * is used for all three types of IPIs.
 */
static void __init leon_ipi_init(void)
{
        int cpu, len;
        struct leon_ipi_work *work;
        struct property *pp;
        struct device_node *rootnp;
        struct tt_entry *trap_table;
        unsigned long flags;

        /* Find IPI IRQ or stick with default value */
        rootnp = of_find_node_by_path("/ambapp0");
        if (rootnp) {
                pp = of_find_property(rootnp, "ipi_num", &len);
                if (pp && (*(int *)pp->value))
                        leon_ipi_irq = *(int *)pp->value;
        }
        printk(KERN_INFO "leon: SMP IPIs at IRQ %d\n", leon_ipi_irq);

        /* Adjust so that we jump directly to smpleon_ipi */
        local_irq_save(flags);
        trap_table = &sparc_ttable[SP_TRAP_IRQ1 + (leon_ipi_irq - 1)];
        trap_table->inst_three += smpleon_ipi - real_irq_entry;
        local_ops->cache_all();
        local_irq_restore(flags);

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

static void leon_send_ipi(int cpu, int level)
{
        unsigned long mask;
        mask = leon_get_irqmask(level);
        LEON3_BYPASS_STORE_PA(&leon3_irqctrl_regs->force[cpu], mask);
}

static void leon_ipi_single(int cpu)
{
        struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);

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

        /* Generate IRQ on the CPU */
        leon_send_ipi(cpu, leon_ipi_irq);
}

static void leon_ipi_mask_one(int cpu)
{
        struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);

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

        /* Generate IRQ on the CPU */
        leon_send_ipi(cpu, leon_ipi_irq);
}

static void leon_ipi_resched(int cpu)
{
        struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);

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

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

void leonsmp_ipi_interrupt(void)
{
        struct leon_ipi_work *work = this_cpu_ptr(&leon_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();
        }
}

static struct smp_funcall {
        smpfunc_t func;
        unsigned long arg1;
        unsigned long arg2;
        unsigned long arg3;
        unsigned long arg4;
        unsigned long arg5;
        unsigned long processors_in[NR_CPUS];   /* Set when ipi entered. */
        unsigned long 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 leon_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 = NR_CPUS - 1;
                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;
                                        leon_send_ipi(i, LEON3_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 leon_cross_call_irq(void)
{
        int i = 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;
}

static const struct sparc32_ipi_ops leon_ipi_ops = {
        .cross_call = leon_cross_call,
        .resched    = leon_ipi_resched,
        .single     = leon_ipi_single,
        .mask_one   = leon_ipi_mask_one,
};

void __init leon_init_smp(void)
{
        /* Patch ipi15 trap table */
        t_nmi[1] = t_nmi[1] + (linux_trap_ipi15_leon - linux_trap_ipi15_sun4m);

        sparc32_ipi_ops = &leon_ipi_ops;
}