// SPDX-License-Identifier: GPL-2.0-only
/*
 *
 * Copyright (C) 2004, 05, 06 MIPS Technologies, Inc.
 *    Elizabeth Clarke (beth@mips.com)
 *    Ralf Baechle (ralf@linux-mips.org)
 * Copyright (C) 2006 Ralf Baechle (ralf@linux-mips.org)
 */
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cpumask.h>
#include <linux/interrupt.h>
#include <linux/compiler.h>
#include <linux/sched/task_stack.h>
#include <linux/smp.h>

#include <linux/atomic.h>
#include <asm/cacheflush.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/hardirq.h>
#include <asm/mmu_context.h>
#include <asm/time.h>
#include <asm/mipsregs.h>
#include <asm/mipsmtregs.h>
#include <asm/mips_mt.h>
#include <asm/mips-cps.h>

static void __init smvp_copy_vpe_config(void)
{
        write_vpe_c0_status(
                (read_c0_status() & ~(ST0_IM | ST0_IE | ST0_KSU)) | ST0_CU0);

        /* set config to be the same as vpe0, particularly kseg0 coherency alg */
        write_vpe_c0_config( read_c0_config());

        /* make sure there are no software interrupts pending */
        write_vpe_c0_cause(0);

        /* Propagate Config7 */
        write_vpe_c0_config7(read_c0_config7());

        write_vpe_c0_count(read_c0_count());
}

static unsigned int __init smvp_vpe_init(unsigned int tc, unsigned int mvpconf0,
        unsigned int ncpu)
{
        if (tc >= smp_max_threads ||
                (tc > ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT)))
                return ncpu;

        /* Deactivate all but VPE 0 */
        if (tc != 0) {
                unsigned long tmp = read_vpe_c0_vpeconf0();

                tmp &= ~VPECONF0_VPA;

                /* master VPE */
                tmp |= VPECONF0_MVP;
                write_vpe_c0_vpeconf0(tmp);

                /* Record this as available CPU */
                set_cpu_possible(tc, true);
                set_cpu_present(tc, true);
                __cpu_number_map[tc]    = ++ncpu;
                __cpu_logical_map[ncpu] = tc;
        }

        /* Disable multi-threading with TC's */
        write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() & ~VPECONTROL_TE);

        if (tc != 0)
                smvp_copy_vpe_config();

        cpu_set_vpe_id(&cpu_data[ncpu], tc);

        return ncpu;
}

static void __init smvp_tc_init(unsigned int tc, unsigned int mvpconf0)
{
        unsigned long tmp;

        if (!tc)
                return;

        /* bind a TC to each VPE, May as well put all excess TC's
           on the last VPE */
        if (tc >= (((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT)+1))
                write_tc_c0_tcbind(read_tc_c0_tcbind() | ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT));
        else {
                write_tc_c0_tcbind(read_tc_c0_tcbind() | tc);

                /* and set XTC */
                write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | (tc << VPECONF0_XTC_SHIFT));
        }

        tmp = read_tc_c0_tcstatus();

        /* mark not allocated and not dynamically allocatable */
        tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
        tmp |= TCSTATUS_IXMT;           /* interrupt exempt */
        write_tc_c0_tcstatus(tmp);

        write_tc_c0_tchalt(TCHALT_H);
}

static void vsmp_init_secondary(void)
{
        /* This is Malta specific: IPI,performance and timer interrupts */
        if (mips_gic_present())
                change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 |
                                         STATUSF_IP4 | STATUSF_IP5 |
                                         STATUSF_IP6 | STATUSF_IP7);
        else
                change_c0_status(ST0_IM, STATUSF_IP0 | STATUSF_IP1 |
                                         STATUSF_IP6 | STATUSF_IP7);
}

static void vsmp_smp_finish(void)
{
        /* CDFIXME: remove this? */
        write_c0_compare(read_c0_count() + (8* mips_hpt_frequency/HZ));

#ifdef CONFIG_MIPS_MT_FPAFF
        /* If we have an FPU, enroll ourselves in the FPU-full mask */
        if (cpu_has_fpu)
                cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask);
#endif /* CONFIG_MIPS_MT_FPAFF */

        local_irq_enable();
}

/*
 * Setup the PC, SP, and GP of a secondary processor and start it
 * running!
 * smp_bootstrap is the place to resume from
 * __KSTK_TOS(idle) is apparently the stack pointer
 * (unsigned long)idle->thread_info the gp
 * assumes a 1:1 mapping of TC => VPE
 */
static int vsmp_boot_secondary(int cpu, struct task_struct *idle)
{
        struct thread_info *gp = task_thread_info(idle);
        dvpe();
        set_c0_mvpcontrol(MVPCONTROL_VPC);

        settc(cpu);

        /* restart */
        write_tc_c0_tcrestart((unsigned long)&smp_bootstrap);

        /* enable the tc this vpe/cpu will be running */
        write_tc_c0_tcstatus((read_tc_c0_tcstatus() & ~TCSTATUS_IXMT) | TCSTATUS_A);

        write_tc_c0_tchalt(0);

        /* enable the VPE */
        write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);

        /* stack pointer */
        write_tc_gpr_sp( __KSTK_TOS(idle));

        /* global pointer */
        write_tc_gpr_gp((unsigned long)gp);

        flush_icache_range((unsigned long)gp,
                           (unsigned long)(gp + sizeof(struct thread_info)));

        /* finally out of configuration and into chaos */
        clear_c0_mvpcontrol(MVPCONTROL_VPC);

        evpe(EVPE_ENABLE);

        return 0;
}

/*
 * Common setup before any secondaries are started
 * Make sure all CPU's are in a sensible state before we boot any of the
 * secondaries
 */
static void __init vsmp_smp_setup(void)
{
        unsigned int mvpconf0, ntc, tc, ncpu = 0;
        unsigned int nvpe;

#ifdef CONFIG_MIPS_MT_FPAFF
        /* If we have an FPU, enroll ourselves in the FPU-full mask */
        if (cpu_has_fpu)
                cpumask_set_cpu(0, &mt_fpu_cpumask);
#endif /* CONFIG_MIPS_MT_FPAFF */
        if (!cpu_has_mipsmt)
                return;

        /* disable MT so we can configure */
        dvpe();
        dmt();

        /* Put MVPE's into 'configuration state' */
        set_c0_mvpcontrol(MVPCONTROL_VPC);

        mvpconf0 = read_c0_mvpconf0();
        ntc = (mvpconf0 & MVPCONF0_PTC) >> MVPCONF0_PTC_SHIFT;

        nvpe = ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
        smp_num_siblings = nvpe;

        /* we'll always have more TC's than VPE's, so loop setting everything
           to a sensible state */
        for (tc = 0; tc <= ntc; tc++) {
                settc(tc);

                smvp_tc_init(tc, mvpconf0);
                ncpu = smvp_vpe_init(tc, mvpconf0, ncpu);
        }

        /* Release config state */
        clear_c0_mvpcontrol(MVPCONTROL_VPC);

        /* We'll wait until starting the secondaries before starting MVPE */

        printk(KERN_INFO "Detected %i available secondary CPU(s)\n", ncpu);
}

static void __init vsmp_prepare_cpus(unsigned int max_cpus)
{
        mips_mt_set_cpuoptions();
}

const struct plat_smp_ops vsmp_smp_ops = {
        .send_ipi_single        = mips_smp_send_ipi_single,
        .send_ipi_mask          = mips_smp_send_ipi_mask,
        .init_secondary         = vsmp_init_secondary,
        .smp_finish             = vsmp_smp_finish,
        .boot_secondary         = vsmp_boot_secondary,
        .smp_setup              = vsmp_smp_setup,
        .prepare_cpus           = vsmp_prepare_cpus,
};