/*
 * This file contains Xilinx specific SMP code, used to start up
 * the second processor.
 *
 * Copyright (C) 2011-2013 Xilinx
 *
 * based on linux/arch/arm/mach-realview/platsmp.c
 *
 * Copyright (C) 2002 ARM Ltd.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/export.h>
#include <linux/jiffies.h>
#include <linux/init.h>
#include <linux/io.h>
#include <asm/cacheflush.h>
#include <asm/smp_scu.h>
#include <linux/irqchip/arm-gic.h>
#include "common.h"

/*
 * Store number of cores in the system
 * Because of scu_get_core_count() must be in __init section and can't
 * be called from zynq_cpun_start() because it is not in __init section.
 */
static int ncores;

int zynq_cpun_start(u32 address, int cpu)
{
        u32 trampoline_code_size = &zynq_secondary_trampoline_end -
                                                &zynq_secondary_trampoline;

        /* MS: Expectation that SLCR are directly map and accessible */
        /* Not possible to jump to non aligned address */
        if (!(address & 3) && (!address || (address >= trampoline_code_size))) {
                /* Store pointer to ioremap area which points to address 0x0 */
                static u8 __iomem *zero;
                u32 trampoline_size = &zynq_secondary_trampoline_jump -
                                                &zynq_secondary_trampoline;

                zynq_slcr_cpu_stop(cpu);
                if (address) {
                        if (__pa(PAGE_OFFSET)) {
                                zero = ioremap(0, trampoline_code_size);
                                if (!zero) {
                                        pr_warn("BOOTUP jump vectors not accessible\n");
                                        return -1;
                                }
                        } else {
                                zero = (__force u8 __iomem *)PAGE_OFFSET;
                        }

                        /*
                        * This is elegant way how to jump to any address
                        * 0x0: Load address at 0x8 to r0
                        * 0x4: Jump by mov instruction
                        * 0x8: Jumping address
                        */
                        memcpy((__force void *)zero, &zynq_secondary_trampoline,
                                                        trampoline_size);
                        writel(address, zero + trampoline_size);

                        flush_cache_all();
                        outer_flush_range(0, trampoline_code_size);
                        smp_wmb();

                        if (__pa(PAGE_OFFSET))
                                iounmap(zero);
                }
                zynq_slcr_cpu_start(cpu);

                return 0;
        }

        pr_warn("Can't start CPU%d: Wrong starting address %x\n", cpu, address);

        return -1;
}
EXPORT_SYMBOL(zynq_cpun_start);

static int zynq_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
        if (!zynq_efuse_cpu_state(cpu))
                return -1;

        return zynq_cpun_start(virt_to_phys(secondary_startup), cpu);
}

/*
 * Initialise the CPU possible map early - this describes the CPUs
 * which may be present or become present in the system.
 */
static void __init zynq_smp_init_cpus(void)
{
        int i;

        ncores = scu_get_core_count(zynq_scu_base);

        for (i = 0; i < ncores && i < CONFIG_NR_CPUS; i++)
                set_cpu_possible(i, true);
}

static void __init zynq_smp_prepare_cpus(unsigned int max_cpus)
{
        scu_enable(zynq_scu_base);
}

/**
 * zynq_secondary_init - Initialize secondary CPU cores
 * @cpu:        CPU that is initialized
 *
 * This function is in the hotplug path. Don't move it into the
 * init section!!
 */
static void zynq_secondary_init(unsigned int cpu)
{
        zynq_core_pm_init();
        zynq_prefetch_init();
}

#ifdef CONFIG_HOTPLUG_CPU
static int zynq_cpu_kill(unsigned cpu)
{
        unsigned long timeout = jiffies + msecs_to_jiffies(50);

        while (zynq_slcr_cpu_state_read(cpu))
                if (time_after(jiffies, timeout))
                        return 0;

        zynq_slcr_cpu_stop(cpu);
        return 1;
}

/**
 * zynq_cpu_die - Let a CPU core die
 * @cpu:        Dying CPU
 *
 * Platform-specific code to shutdown a CPU.
 * Called with IRQs disabled on the dying CPU.
 */
static void zynq_cpu_die(unsigned int cpu)
{
        zynq_slcr_cpu_state_write(cpu, true);

        /*
         * there is no power-control hardware on this platform, so all
         * we can do is put the core into WFI; this is safe as the calling
         * code will have already disabled interrupts
         */
        for (;;)
                cpu_do_idle();
}
#endif

const struct smp_operations zynq_smp_ops __initconst = {
        .smp_init_cpus          = zynq_smp_init_cpus,
        .smp_prepare_cpus       = zynq_smp_prepare_cpus,
        .smp_boot_secondary     = zynq_boot_secondary,
        .smp_secondary_init     = zynq_secondary_init,
#ifdef CONFIG_HOTPLUG_CPU
        .cpu_die                = zynq_cpu_die,
        .cpu_kill               = zynq_cpu_kill,
#endif
};