/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2004-2008, 2009, 2010 Cavium Networks
 */
#include <linux/cpu.h>
#include <linux/delay.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/sched.h>
#include <linux/sched/hotplug.h>
#include <linux/sched/task_stack.h>
#include <linux/init.h>
#include <linux/export.h>

#include <asm/mmu_context.h>
#include <asm/time.h>
#include <asm/setup.h>

#include <asm/octeon/octeon.h>

#include "octeon_boot.h"

volatile unsigned long octeon_processor_boot = 0xff;
volatile unsigned long octeon_processor_sp;
volatile unsigned long octeon_processor_gp;
#ifdef CONFIG_RELOCATABLE
volatile unsigned long octeon_processor_relocated_kernel_entry;
#endif /* CONFIG_RELOCATABLE */

#ifdef CONFIG_HOTPLUG_CPU
uint64_t octeon_bootloader_entry_addr;
EXPORT_SYMBOL(octeon_bootloader_entry_addr);
#endif

extern void kernel_entry(unsigned long arg1, ...);

static void octeon_icache_flush(void)
{
        asm volatile ("synci 0($0)\n");
}

static void (*octeon_message_functions[8])(void) = {
        scheduler_ipi,
        generic_smp_call_function_interrupt,
        octeon_icache_flush,
};

static irqreturn_t mailbox_interrupt(int irq, void *dev_id)
{
        u64 mbox_clrx = CVMX_CIU_MBOX_CLRX(cvmx_get_core_num());
        u64 action;
        int i;

        /*
         * Make sure the function array initialization remains
         * correct.
         */
        BUILD_BUG_ON(SMP_RESCHEDULE_YOURSELF != (1 << 0));
        BUILD_BUG_ON(SMP_CALL_FUNCTION       != (1 << 1));
        BUILD_BUG_ON(SMP_ICACHE_FLUSH        != (1 << 2));

        /*
         * Load the mailbox register to figure out what we're supposed
         * to do.
         */
        action = cvmx_read_csr(mbox_clrx);

        if (OCTEON_IS_MODEL(OCTEON_CN68XX))
                action &= 0xff;
        else
                action &= 0xffff;

        /* Clear the mailbox to clear the interrupt */
        cvmx_write_csr(mbox_clrx, action);

        for (i = 0; i < ARRAY_SIZE(octeon_message_functions) && action;) {
                if (action & 1) {
                        void (*fn)(void) = octeon_message_functions[i];

                        if (fn)
                                fn();
                }
                action >>= 1;
                i++;
        }
        return IRQ_HANDLED;
}

/**
 * Cause the function described by call_data to be executed on the passed
 * cpu.  When the function has finished, increment the finished field of
 * call_data.
 */
void octeon_send_ipi_single(int cpu, unsigned int action)
{
        int coreid = cpu_logical_map(cpu);
        /*
        pr_info("SMP: Mailbox send cpu=%d, coreid=%d, action=%u\n", cpu,
               coreid, action);
        */
        cvmx_write_csr(CVMX_CIU_MBOX_SETX(coreid), action);
}

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

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

/**
 * Detect available CPUs, populate cpu_possible_mask
 */
static void octeon_smp_hotplug_setup(void)
{
#ifdef CONFIG_HOTPLUG_CPU
        struct linux_app_boot_info *labi;

        if (!setup_max_cpus)
                return;

        labi = (struct linux_app_boot_info *)PHYS_TO_XKSEG_CACHED(LABI_ADDR_IN_BOOTLOADER);
        if (labi->labi_signature != LABI_SIGNATURE) {
                pr_info("The bootloader on this board does not support HOTPLUG_CPU.");
                return;
        }

        octeon_bootloader_entry_addr = labi->InitTLBStart_addr;
#endif
}

static void __init octeon_smp_setup(void)
{
        const int coreid = cvmx_get_core_num();
        int cpus;
        int id;
        struct cvmx_sysinfo *sysinfo = cvmx_sysinfo_get();

#ifdef CONFIG_HOTPLUG_CPU
        int core_mask = octeon_get_boot_coremask();
        unsigned int num_cores = cvmx_octeon_num_cores();
#endif

        /* The present CPUs are initially just the boot cpu (CPU 0). */
        for (id = 0; id < NR_CPUS; id++) {
                set_cpu_possible(id, id == 0);
                set_cpu_present(id, id == 0);
        }

        __cpu_number_map[coreid] = 0;
        __cpu_logical_map[0] = coreid;

        /* The present CPUs get the lowest CPU numbers. */
        cpus = 1;
        for (id = 0; id < NR_CPUS; id++) {
                if ((id != coreid) && cvmx_coremask_is_core_set(&sysinfo->core_mask, id)) {
                        set_cpu_possible(cpus, true);
                        set_cpu_present(cpus, true);
                        __cpu_number_map[id] = cpus;
                        __cpu_logical_map[cpus] = id;
                        cpus++;
                }
        }

#ifdef CONFIG_HOTPLUG_CPU
        /*
         * The possible CPUs are all those present on the chip.  We
         * will assign CPU numbers for possible cores as well.  Cores
         * are always consecutively numberd from 0.
         */
        for (id = 0; setup_max_cpus && octeon_bootloader_entry_addr &&
                     id < num_cores && id < NR_CPUS; id++) {
                if (!(core_mask & (1 << id))) {
                        set_cpu_possible(cpus, true);
                        __cpu_number_map[id] = cpus;
                        __cpu_logical_map[cpus] = id;
                        cpus++;
                }
        }
#endif

        octeon_smp_hotplug_setup();
}


#ifdef CONFIG_RELOCATABLE
int plat_post_relocation(long offset)
{
        unsigned long entry = (unsigned long)kernel_entry;

        /* Send secondaries into relocated kernel */
        octeon_processor_relocated_kernel_entry = entry + offset;

        return 0;
}
#endif /* CONFIG_RELOCATABLE */

/**
 * Firmware CPU startup hook
 *
 */
static int octeon_boot_secondary(int cpu, struct task_struct *idle)
{
        int count;

        pr_info("SMP: Booting CPU%02d (CoreId %2d)...\n", cpu,
                cpu_logical_map(cpu));

        octeon_processor_sp = __KSTK_TOS(idle);
        octeon_processor_gp = (unsigned long)(task_thread_info(idle));
        octeon_processor_boot = cpu_logical_map(cpu);
        mb();

        count = 10000;
        while (octeon_processor_sp && count) {
                /* Waiting for processor to get the SP and GP */
                udelay(1);
                count--;
        }
        if (count == 0) {
                pr_err("Secondary boot timeout\n");
                return -ETIMEDOUT;
        }

        return 0;
}

/**
 * After we've done initial boot, this function is called to allow the
 * board code to clean up state, if needed
 */
static void octeon_init_secondary(void)
{
        unsigned int sr;

        sr = set_c0_status(ST0_BEV);
        write_c0_ebase((u32)ebase);
        write_c0_status(sr);

        octeon_check_cpu_bist();
        octeon_init_cvmcount();

        octeon_irq_setup_secondary();
}

/**
 * Callout to firmware before smp_init
 *
 */
static void __init octeon_prepare_cpus(unsigned int max_cpus)
{
        /*
         * Only the low order mailbox bits are used for IPIs, leave
         * the other bits alone.
         */
        cvmx_write_csr(CVMX_CIU_MBOX_CLRX(cvmx_get_core_num()), 0xffff);
        if (request_irq(OCTEON_IRQ_MBOX0, mailbox_interrupt,
                        IRQF_PERCPU | IRQF_NO_THREAD, "SMP-IPI",
                        mailbox_interrupt)) {
                panic("Cannot request_irq(OCTEON_IRQ_MBOX0)");
        }
}

/**
 * Last chance for the board code to finish SMP initialization before
 * the CPU is "online".
 */
static void octeon_smp_finish(void)
{
        octeon_user_io_init();

        /* to generate the first CPU timer interrupt */
        write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ);
        local_irq_enable();
}

#ifdef CONFIG_HOTPLUG_CPU

/* State of each CPU. */
DEFINE_PER_CPU(int, cpu_state);

static int octeon_cpu_disable(void)
{
        unsigned int cpu = smp_processor_id();

        if (cpu == 0)
                return -EBUSY;

        if (!octeon_bootloader_entry_addr)
                return -ENOTSUPP;

        set_cpu_online(cpu, false);
        calculate_cpu_foreign_map();
        octeon_fixup_irqs();

        __flush_cache_all();
        local_flush_tlb_all();

        return 0;
}

static void octeon_cpu_die(unsigned int cpu)
{
        int coreid = cpu_logical_map(cpu);
        uint32_t mask, new_mask;
        const struct cvmx_bootmem_named_block_desc *block_desc;

        while (per_cpu(cpu_state, cpu) != CPU_DEAD)
                cpu_relax();

        /*
         * This is a bit complicated strategics of getting/settig available
         * cores mask, copied from bootloader
         */

        mask = 1 << coreid;
        /* LINUX_APP_BOOT_BLOCK is initialized in bootoct binary */
        block_desc = cvmx_bootmem_find_named_block(LINUX_APP_BOOT_BLOCK_NAME);

        if (!block_desc) {
                struct linux_app_boot_info *labi;

                labi = (struct linux_app_boot_info *)PHYS_TO_XKSEG_CACHED(LABI_ADDR_IN_BOOTLOADER);

                labi->avail_coremask |= mask;
                new_mask = labi->avail_coremask;
        } else {                       /* alternative, already initialized */
                uint32_t *p = (uint32_t *)PHYS_TO_XKSEG_CACHED(block_desc->base_addr +
                                                               AVAIL_COREMASK_OFFSET_IN_LINUX_APP_BOOT_BLOCK);
                *p |= mask;
                new_mask = *p;
        }

        pr_info("Reset core %d. Available Coremask = 0x%x \n", coreid, new_mask);
        mb();
        cvmx_write_csr(CVMX_CIU_PP_RST, 1 << coreid);
        cvmx_write_csr(CVMX_CIU_PP_RST, 0);
}

void play_dead(void)
{
        int cpu = cpu_number_map(cvmx_get_core_num());

        idle_task_exit();
        octeon_processor_boot = 0xff;
        per_cpu(cpu_state, cpu) = CPU_DEAD;

        mb();

        while (1)       /* core will be reset here */
                ;
}

static void start_after_reset(void)
{
        kernel_entry(0, 0, 0);  /* set a2 = 0 for secondary core */
}

static int octeon_update_boot_vector(unsigned int cpu)
{

        int coreid = cpu_logical_map(cpu);
        uint32_t avail_coremask;
        const struct cvmx_bootmem_named_block_desc *block_desc;
        struct boot_init_vector *boot_vect =
                (struct boot_init_vector *)PHYS_TO_XKSEG_CACHED(BOOTLOADER_BOOT_VECTOR);

        block_desc = cvmx_bootmem_find_named_block(LINUX_APP_BOOT_BLOCK_NAME);

        if (!block_desc) {
                struct linux_app_boot_info *labi;

                labi = (struct linux_app_boot_info *)PHYS_TO_XKSEG_CACHED(LABI_ADDR_IN_BOOTLOADER);

                avail_coremask = labi->avail_coremask;
                labi->avail_coremask &= ~(1 << coreid);
        } else {                       /* alternative, already initialized */
                avail_coremask = *(uint32_t *)PHYS_TO_XKSEG_CACHED(
                        block_desc->base_addr + AVAIL_COREMASK_OFFSET_IN_LINUX_APP_BOOT_BLOCK);
        }

        if (!(avail_coremask & (1 << coreid))) {
                /* core not available, assume, that caught by simple-executive */
                cvmx_write_csr(CVMX_CIU_PP_RST, 1 << coreid);
                cvmx_write_csr(CVMX_CIU_PP_RST, 0);
        }

        boot_vect[coreid].app_start_func_addr =
                (uint32_t) (unsigned long) start_after_reset;
        boot_vect[coreid].code_addr = octeon_bootloader_entry_addr;

        mb();

        cvmx_write_csr(CVMX_CIU_NMI, (1 << coreid) & avail_coremask);

        return 0;
}

static int register_cavium_notifier(void)
{
        return cpuhp_setup_state_nocalls(CPUHP_MIPS_SOC_PREPARE,
                                         "mips/cavium:prepare",
                                         octeon_update_boot_vector, NULL);
}
late_initcall(register_cavium_notifier);

#endif  /* CONFIG_HOTPLUG_CPU */

const struct plat_smp_ops octeon_smp_ops = {
        .send_ipi_single        = octeon_send_ipi_single,
        .send_ipi_mask          = octeon_send_ipi_mask,
        .init_secondary         = octeon_init_secondary,
        .smp_finish             = octeon_smp_finish,
        .boot_secondary         = octeon_boot_secondary,
        .smp_setup              = octeon_smp_setup,
        .prepare_cpus           = octeon_prepare_cpus,
#ifdef CONFIG_HOTPLUG_CPU
        .cpu_disable            = octeon_cpu_disable,
        .cpu_die                = octeon_cpu_die,
#endif
};

static irqreturn_t octeon_78xx_reched_interrupt(int irq, void *dev_id)
{
        scheduler_ipi();
        return IRQ_HANDLED;
}

static irqreturn_t octeon_78xx_call_function_interrupt(int irq, void *dev_id)
{
        generic_smp_call_function_interrupt();
        return IRQ_HANDLED;
}

static irqreturn_t octeon_78xx_icache_flush_interrupt(int irq, void *dev_id)
{
        octeon_icache_flush();
        return IRQ_HANDLED;
}

/*
 * Callout to firmware before smp_init
 */
static void octeon_78xx_prepare_cpus(unsigned int max_cpus)
{
        if (request_irq(OCTEON_IRQ_MBOX0 + 0,
                        octeon_78xx_reched_interrupt,
                        IRQF_PERCPU | IRQF_NO_THREAD, "Scheduler",
                        octeon_78xx_reched_interrupt)) {
                panic("Cannot request_irq for SchedulerIPI");
        }
        if (request_irq(OCTEON_IRQ_MBOX0 + 1,
                        octeon_78xx_call_function_interrupt,
                        IRQF_PERCPU | IRQF_NO_THREAD, "SMP-Call",
                        octeon_78xx_call_function_interrupt)) {
                panic("Cannot request_irq for SMP-Call");
        }
        if (request_irq(OCTEON_IRQ_MBOX0 + 2,
                        octeon_78xx_icache_flush_interrupt,
                        IRQF_PERCPU | IRQF_NO_THREAD, "ICache-Flush",
                        octeon_78xx_icache_flush_interrupt)) {
                panic("Cannot request_irq for ICache-Flush");
        }
}

static void octeon_78xx_send_ipi_single(int cpu, unsigned int action)
{
        int i;

        for (i = 0; i < 8; i++) {
                if (action & 1)
                        octeon_ciu3_mbox_send(cpu, i);
                action >>= 1;
        }
}

static void octeon_78xx_send_ipi_mask(const struct cpumask *mask,
                                      unsigned int action)
{
        unsigned int cpu;

        for_each_cpu(cpu, mask)
                octeon_78xx_send_ipi_single(cpu, action);
}

static const struct plat_smp_ops octeon_78xx_smp_ops = {
        .send_ipi_single        = octeon_78xx_send_ipi_single,
        .send_ipi_mask          = octeon_78xx_send_ipi_mask,
        .init_secondary         = octeon_init_secondary,
        .smp_finish             = octeon_smp_finish,
        .boot_secondary         = octeon_boot_secondary,
        .smp_setup              = octeon_smp_setup,
        .prepare_cpus           = octeon_78xx_prepare_cpus,
#ifdef CONFIG_HOTPLUG_CPU
        .cpu_disable            = octeon_cpu_disable,
        .cpu_die                = octeon_cpu_die,
#endif
};

void __init octeon_setup_smp(void)
{
        const struct plat_smp_ops *ops;

        if (octeon_has_feature(OCTEON_FEATURE_CIU3))
                ops = &octeon_78xx_smp_ops;
        else
                ops = &octeon_smp_ops;

        register_smp_ops(ops);
}