/*
 * Symmetric Multi Processing (SMP) support for Armada XP
 *
 * Copyright (C) 2012 Marvell
 *
 * Lior Amsalem <alior@marvell.com>
 * Yehuda Yitschak <yehuday@marvell.com>
 * Gregory CLEMENT <gregory.clement@free-electrons.com>
 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 *
 * The Armada XP SoC has 4 ARMv7 PJ4B CPUs running in full HW coherency
 * This file implements the routines for preparing the SMP infrastructure
 * and waking up the secondary CPUs
 */

#include <linux/init.h>
#include <linux/smp.h>
#include <linux/clk.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/mbus.h>
#include <asm/cacheflush.h>
#include <asm/smp_plat.h>
#include "common.h"
#include "armada-370-xp.h"
#include "pmsu.h"
#include "coherency.h"

#define ARMADA_XP_MAX_CPUS 4

#define AXP_BOOTROM_BASE 0xfff00000
#define AXP_BOOTROM_SIZE 0x100000

static struct clk *boot_cpu_clk;

static struct clk *get_cpu_clk(int cpu)
{
        struct clk *cpu_clk;
        struct device_node *np = of_get_cpu_node(cpu, NULL);

        if (WARN(!np, "missing cpu node\n"))
                return NULL;
        cpu_clk = of_clk_get(np, 0);
        if (WARN_ON(IS_ERR(cpu_clk)))
                return NULL;
        return cpu_clk;
}

static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
        int ret, hw_cpu;

        pr_info("Booting CPU %d\n", cpu);

        hw_cpu = cpu_logical_map(cpu);
        mvebu_pmsu_set_cpu_boot_addr(hw_cpu, armada_xp_secondary_startup);

        /*
         * This is needed to wake up CPUs in the offline state after
         * using CPU hotplug.
         */
        arch_send_wakeup_ipi_mask(cpumask_of(cpu));

        /*
         * This is needed to take secondary CPUs out of reset on the
         * initial boot.
         */
        ret = mvebu_cpu_reset_deassert(hw_cpu);
        if (ret) {
                pr_warn("unable to boot CPU: %d\n", ret);
                return ret;
        }

        return 0;
}

/*
 * When a CPU is brought back online, either through CPU hotplug, or
 * because of the boot of a kexec'ed kernel, the PMSU configuration
 * for this CPU might be in the deep idle state, preventing this CPU
 * from receiving interrupts. Here, we therefore take out the current
 * CPU from this state, which was entered by armada_xp_cpu_die()
 * below.
 */
static void armada_xp_secondary_init(unsigned int cpu)
{
        mvebu_v7_pmsu_idle_exit();
}

static void __init armada_xp_smp_init_cpus(void)
{
        unsigned int ncores = num_possible_cpus();

        if (ncores == 0 || ncores > ARMADA_XP_MAX_CPUS)
                panic("Invalid number of CPUs in DT\n");
}

static int armada_xp_sync_secondary_clk(unsigned int cpu)
{
        struct clk *cpu_clk = get_cpu_clk(cpu);

        if (!cpu_clk || !boot_cpu_clk)
                return 0;

        clk_prepare_enable(cpu_clk);
        clk_set_rate(cpu_clk, clk_get_rate(boot_cpu_clk));

        return 0;
}

static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus)
{
        struct device_node *node;
        struct resource res;
        int err;

        flush_cache_all();
        set_cpu_coherent();

        boot_cpu_clk = get_cpu_clk(smp_processor_id());
        if (boot_cpu_clk) {
                clk_prepare_enable(boot_cpu_clk);
                cpuhp_setup_state_nocalls(CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS,
                                          "arm/mvebu/sync_clocks:online",
                                          armada_xp_sync_secondary_clk, NULL);
        }

        /*
         * In order to boot the secondary CPUs we need to ensure
         * the bootROM is mapped at the correct address.
         */
        node = of_find_compatible_node(NULL, NULL, "marvell,bootrom");
        if (!node)
                panic("Cannot find 'marvell,bootrom' compatible node");

        err = of_address_to_resource(node, 0, &res);
        of_node_put(node);
        if (err < 0)
                panic("Cannot get 'bootrom' node address");

        if (res.start != AXP_BOOTROM_BASE ||
            resource_size(&res) != AXP_BOOTROM_SIZE)
                panic("The address for the BootROM is incorrect");
}

#ifdef CONFIG_HOTPLUG_CPU
static void armada_xp_cpu_die(unsigned int cpu)
{
        /*
         * CPU hotplug is implemented by putting offline CPUs into the
         * deep idle sleep state.
         */
        armada_370_xp_pmsu_idle_enter(true);
}

/*
 * We need a dummy function, so that platform_can_cpu_hotplug() knows
 * we support CPU hotplug. However, the function does not need to do
 * anything, because CPUs going offline can enter the deep idle state
 * by themselves, without any help from a still alive CPU.
 */
static int armada_xp_cpu_kill(unsigned int cpu)
{
        return 1;
}
#endif

const struct smp_operations armada_xp_smp_ops __initconst = {
        .smp_init_cpus          = armada_xp_smp_init_cpus,
        .smp_prepare_cpus       = armada_xp_smp_prepare_cpus,
        .smp_boot_secondary     = armada_xp_boot_secondary,
        .smp_secondary_init     = armada_xp_secondary_init,
#ifdef CONFIG_HOTPLUG_CPU
        .cpu_die                = armada_xp_cpu_die,
        .cpu_kill               = armada_xp_cpu_kill,
#endif
};

CPU_METHOD_OF_DECLARE(armada_xp_smp, "marvell,armada-xp-smp",
                      &armada_xp_smp_ops);

#define MV98DX3236_CPU_RESUME_CTRL_REG 0x08
#define MV98DX3236_CPU_RESUME_ADDR_REG 0x04

static const struct of_device_id of_mv98dx3236_resume_table[] = {
        {
                .compatible = "marvell,98dx3336-resume-ctrl",
        },
        { /* end of list */ },
};

static int mv98dx3236_resume_set_cpu_boot_addr(int hw_cpu, void *boot_addr)
{
        struct device_node *np;
        void __iomem *base;
        WARN_ON(hw_cpu != 1);

        np = of_find_matching_node(NULL, of_mv98dx3236_resume_table);
        if (!np)
                return -ENODEV;

        base = of_io_request_and_map(np, 0, of_node_full_name(np));
        of_node_put(np);
        if (IS_ERR(base))
                return PTR_ERR(base);

        writel(0, base + MV98DX3236_CPU_RESUME_CTRL_REG);
        writel(__pa_symbol(boot_addr), base + MV98DX3236_CPU_RESUME_ADDR_REG);

        iounmap(base);

        return 0;
}

static int mv98dx3236_boot_secondary(unsigned int cpu, struct task_struct *idle)
{
        int ret, hw_cpu;

        hw_cpu = cpu_logical_map(cpu);
        mv98dx3236_resume_set_cpu_boot_addr(hw_cpu,
                                            armada_xp_secondary_startup);

        /*
         * This is needed to wake up CPUs in the offline state after
         * using CPU hotplug.
         */
        arch_send_wakeup_ipi_mask(cpumask_of(cpu));

        /*
         * This is needed to take secondary CPUs out of reset on the
         * initial boot.
         */
        ret = mvebu_cpu_reset_deassert(hw_cpu);
        if (ret) {
                pr_warn("unable to boot CPU: %d\n", ret);
                return ret;
        }

        return 0;
}

static const struct smp_operations mv98dx3236_smp_ops __initconst = {
        .smp_init_cpus          = armada_xp_smp_init_cpus,
        .smp_prepare_cpus       = armada_xp_smp_prepare_cpus,
        .smp_boot_secondary     = mv98dx3236_boot_secondary,
        .smp_secondary_init     = armada_xp_secondary_init,
#ifdef CONFIG_HOTPLUG_CPU
        .cpu_die                = armada_xp_cpu_die,
        .cpu_kill               = armada_xp_cpu_kill,
#endif
};

CPU_METHOD_OF_DECLARE(mv98dx3236_smp, "marvell,98dx3236-smp",
                      &mv98dx3236_smp_ops);