/*
 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
 *              http://www.samsung.com
 *
 * arch/arm/mach-exynos/mcpm-exynos.c
 *
 * Based on arch/arm/mach-vexpress/dcscb.c
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/arm-cci.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/syscore_ops.h>
#include <linux/soc/samsung/exynos-regs-pmu.h>

#include <asm/cputype.h>
#include <asm/cp15.h>
#include <asm/mcpm.h>
#include <asm/smp_plat.h>

#include "common.h"

#define EXYNOS5420_CPUS_PER_CLUSTER     4
#define EXYNOS5420_NR_CLUSTERS          2

#define EXYNOS5420_ENABLE_AUTOMATIC_CORE_DOWN   BIT(9)
#define EXYNOS5420_USE_ARM_CORE_DOWN_STATE      BIT(29)
#define EXYNOS5420_USE_L2_COMMON_UP_STATE       BIT(30)

static void __iomem *ns_sram_base_addr;

/*
 * The common v7_exit_coherency_flush API could not be used because of the
 * Erratum 799270 workaround. This macro is the same as the common one (in
 * arch/arm/include/asm/cacheflush.h) except for the erratum handling.
 */
#define exynos_v7_exit_coherency_flush(level) \
        asm volatile( \
        "stmfd  sp!, {fp, ip}\n\t"\
        "mrc    p15, 0, r0, c1, c0, 0   @ get SCTLR\n\t" \
        "bic    r0, r0, #"__stringify(CR_C)"\n\t" \
        "mcr    p15, 0, r0, c1, c0, 0   @ set SCTLR\n\t" \
        "isb\n\t"\
        "bl     v7_flush_dcache_"__stringify(level)"\n\t" \
        "mrc    p15, 0, r0, c1, c0, 1   @ get ACTLR\n\t" \
        "bic    r0, r0, #(1 << 6)       @ disable local coherency\n\t" \
        /* Dummy Load of a device register to avoid Erratum 799270 */ \
        "ldr    r4, [%0]\n\t" \
        "and    r4, r4, #0\n\t" \
        "orr    r0, r0, r4\n\t" \
        "mcr    p15, 0, r0, c1, c0, 1   @ set ACTLR\n\t" \
        "isb\n\t" \
        "dsb\n\t" \
        "ldmfd  sp!, {fp, ip}" \
        : \
        : "Ir" (pmu_base_addr + S5P_INFORM0) \
        : "r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7", \
          "r9", "r10", "lr", "memory")

static int exynos_cpu_powerup(unsigned int cpu, unsigned int cluster)
{
        unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);

        pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
        if (cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
                cluster >= EXYNOS5420_NR_CLUSTERS)
                return -EINVAL;

        if (!exynos_cpu_power_state(cpunr)) {
                exynos_cpu_power_up(cpunr);

                /*
                 * This assumes the cluster number of the big cores(Cortex A15)
                 * is 0 and the Little cores(Cortex A7) is 1.
                 * When the system was booted from the Little core,
                 * they should be reset during power up cpu.
                 */
                if (cluster &&
                    cluster == MPIDR_AFFINITY_LEVEL(cpu_logical_map(0), 1)) {
                        /*
                         * Before we reset the Little cores, we should wait
                         * the SPARE2 register is set to 1 because the init
                         * codes of the iROM will set the register after
                         * initialization.
                         */
                        while (!pmu_raw_readl(S5P_PMU_SPARE2))
                                udelay(10);

                        pmu_raw_writel(EXYNOS5420_KFC_CORE_RESET(cpu),
                                        EXYNOS_SWRESET);
                }
        }

        return 0;
}

static int exynos_cluster_powerup(unsigned int cluster)
{
        pr_debug("%s: cluster %u\n", __func__, cluster);
        if (cluster >= EXYNOS5420_NR_CLUSTERS)
                return -EINVAL;

        exynos_cluster_power_up(cluster);
        return 0;
}

static void exynos_cpu_powerdown_prepare(unsigned int cpu, unsigned int cluster)
{
        unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);

        pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
        BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
                        cluster >= EXYNOS5420_NR_CLUSTERS);
        exynos_cpu_power_down(cpunr);
}

static void exynos_cluster_powerdown_prepare(unsigned int cluster)
{
        pr_debug("%s: cluster %u\n", __func__, cluster);
        BUG_ON(cluster >= EXYNOS5420_NR_CLUSTERS);
        exynos_cluster_power_down(cluster);
}

static void exynos_cpu_cache_disable(void)
{
        /* Disable and flush the local CPU cache. */
        exynos_v7_exit_coherency_flush(louis);
}

static void exynos_cluster_cache_disable(void)
{
        if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A15) {
                /*
                 * On the Cortex-A15 we need to disable
                 * L2 prefetching before flushing the cache.
                 */
                asm volatile(
                "mcr    p15, 1, %0, c15, c0, 3\n\t"
                "isb\n\t"
                "dsb"
                : : "r" (0x400));
        }

        /* Flush all cache levels for this cluster. */
        exynos_v7_exit_coherency_flush(all);

        /*
         * Disable cluster-level coherency by masking
         * incoming snoops and DVM messages:
         */
        cci_disable_port_by_cpu(read_cpuid_mpidr());
}

static int exynos_wait_for_powerdown(unsigned int cpu, unsigned int cluster)
{
        unsigned int tries = 100;
        unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);

        pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
        BUG_ON(cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
                        cluster >= EXYNOS5420_NR_CLUSTERS);

        /* Wait for the core state to be OFF */
        while (tries--) {
                if ((exynos_cpu_power_state(cpunr) == 0))
                        return 0; /* success: the CPU is halted */

                /* Otherwise, wait and retry: */
                msleep(1);
        }

        return -ETIMEDOUT; /* timeout */
}

static void exynos_cpu_is_up(unsigned int cpu, unsigned int cluster)
{
        /* especially when resuming: make sure power control is set */
        exynos_cpu_powerup(cpu, cluster);
}

static const struct mcpm_platform_ops exynos_power_ops = {
        .cpu_powerup            = exynos_cpu_powerup,
        .cluster_powerup        = exynos_cluster_powerup,
        .cpu_powerdown_prepare  = exynos_cpu_powerdown_prepare,
        .cluster_powerdown_prepare = exynos_cluster_powerdown_prepare,
        .cpu_cache_disable      = exynos_cpu_cache_disable,
        .cluster_cache_disable  = exynos_cluster_cache_disable,
        .wait_for_powerdown     = exynos_wait_for_powerdown,
        .cpu_is_up              = exynos_cpu_is_up,
};

/*
 * Enable cluster-level coherency, in preparation for turning on the MMU.
 */
static void __naked exynos_pm_power_up_setup(unsigned int affinity_level)
{
        asm volatile ("\n"
        "cmp    r0, #1\n"
        "bxne   lr\n"
        "b      cci_enable_port_for_self");
}

static const struct of_device_id exynos_dt_mcpm_match[] = {
        { .compatible = "samsung,exynos5420" },
        { .compatible = "samsung,exynos5800" },
        {},
};

static void exynos_mcpm_setup_entry_point(void)
{
        /*
         * U-Boot SPL is hardcoded to jump to the start of ns_sram_base_addr
         * as part of secondary_cpu_start().  Let's redirect it to the
         * mcpm_entry_point(). This is done during both secondary boot-up as
         * well as system resume.
         */
        __raw_writel(0xe59f0000, ns_sram_base_addr);     /* ldr r0, [pc, #0] */
        __raw_writel(0xe12fff10, ns_sram_base_addr + 4); /* bx  r0 */
        __raw_writel(virt_to_phys(mcpm_entry_point), ns_sram_base_addr + 8);
}

static struct syscore_ops exynos_mcpm_syscore_ops = {
        .resume = exynos_mcpm_setup_entry_point,
};

static int __init exynos_mcpm_init(void)
{
        struct device_node *node;
        unsigned int value, i;
        int ret;

        node = of_find_matching_node(NULL, exynos_dt_mcpm_match);
        if (!node)
                return -ENODEV;
        of_node_put(node);

        if (!cci_probed())
                return -ENODEV;

        node = of_find_compatible_node(NULL, NULL,
                        "samsung,exynos4210-sysram-ns");
        if (!node)
                return -ENODEV;

        ns_sram_base_addr = of_iomap(node, 0);
        of_node_put(node);
        if (!ns_sram_base_addr) {
                pr_err("failed to map non-secure iRAM base address\n");
                return -ENOMEM;
        }

        /*
         * To increase the stability of KFC reset we need to program
         * the PMU SPARE3 register
         */
        pmu_raw_writel(EXYNOS5420_SWRESET_KFC_SEL, S5P_PMU_SPARE3);

        ret = mcpm_platform_register(&exynos_power_ops);
        if (!ret)
                ret = mcpm_sync_init(exynos_pm_power_up_setup);
        if (!ret)
                ret = mcpm_loopback(exynos_cluster_cache_disable); /* turn on the CCI */
        if (ret) {
                iounmap(ns_sram_base_addr);
                return ret;
        }

        mcpm_smp_set_ops();

        pr_info("Exynos MCPM support installed\n");

        /*
         * On Exynos5420/5800 for the A15 and A7 clusters:
         *
         * EXYNOS5420_ENABLE_AUTOMATIC_CORE_DOWN ensures that all the cores
         * in a cluster are turned off before turning off the cluster L2.
         *
         * EXYNOS5420_USE_ARM_CORE_DOWN_STATE ensures that a cores is powered
         * off before waking it up.
         *
         * EXYNOS5420_USE_L2_COMMON_UP_STATE ensures that cluster L2 will be
         * turned on before the first man is powered up.
         */
        for (i = 0; i < EXYNOS5420_NR_CLUSTERS; i++) {
                value = pmu_raw_readl(EXYNOS_COMMON_OPTION(i));
                value |= EXYNOS5420_ENABLE_AUTOMATIC_CORE_DOWN |
                         EXYNOS5420_USE_ARM_CORE_DOWN_STATE    |
                         EXYNOS5420_USE_L2_COMMON_UP_STATE;
                pmu_raw_writel(value, EXYNOS_COMMON_OPTION(i));
        }

        exynos_mcpm_setup_entry_point();

        register_syscore_ops(&exynos_mcpm_syscore_ops);

        return ret;
}

early_initcall(exynos_mcpm_init);