platsmp.c

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/*
 *  linux/arch/arm/mach-vexpress/platsmp.c
 *
 *  Copyright (C) 2002 ARM Ltd.
 *  All Rights Reserved
 *
 * 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/init.h>
#include <linux/errno.h>
#include <linux/smp.h>
#include <linux/io.h>
#include <linux/of_fdt.h>

#include <asm/smp_scu.h>
#include <asm/hardware/gic.h>
#include <asm/mach/map.h>

#include <mach/motherboard.h>

#include <plat/platsmp.h>

#include "core.h"

#if defined(CONFIG_OF)

static enum {
    GENERIC_SCU,
    CORTEX_A9_SCU,
} vexpress_dt_scu __initdata = GENERIC_SCU;

static struct map_desc vexpress_dt_cortex_a9_scu_map __initdata = {
    .virtual    = V2T_PERIPH,
    /* .pfn set in vexpress_dt_init_cortex_a9_scu() */
    .length     = SZ_128,
    .type       = MT_DEVICE,
};

static void *vexpress_dt_cortex_a9_scu_base __initdata;

const static char *vexpress_dt_cortex_a9_match[] __initconst = {
    "arm,cortex-a5-scu",
    "arm,cortex-a9-scu",
    NULL
};

static int __init vexpress_dt_find_scu(unsigned long node,
        const char *uname, int depth, void *data)
{
    if (of_flat_dt_match(node, vexpress_dt_cortex_a9_match)) {
        phys_addr_t phys_addr;
        __be32 *reg = of_get_flat_dt_prop(node, "reg", NULL);

        if (WARN_ON(!reg))
            return -EINVAL;

        phys_addr = be32_to_cpup(reg);
        vexpress_dt_scu = CORTEX_A9_SCU;

        vexpress_dt_cortex_a9_scu_map.pfn = __phys_to_pfn(phys_addr);
        iotable_init(&vexpress_dt_cortex_a9_scu_map, 1);
        vexpress_dt_cortex_a9_scu_base = ioremap(phys_addr, SZ_256);
        if (WARN_ON(!vexpress_dt_cortex_a9_scu_base))
            return -EFAULT;
    }

    return 0;
}

void __init vexpress_dt_smp_map_io(void)
{
    if (initial_boot_params)
        WARN_ON(of_scan_flat_dt(vexpress_dt_find_scu, NULL));
}

static int __init vexpress_dt_cpus_num(unsigned long node, const char *uname,
        int depth, void *data)
{
    static int prev_depth = -1;
    static int nr_cpus = -1;

    if (prev_depth > depth && nr_cpus > 0)
        return nr_cpus;

    if (nr_cpus < 0 && strcmp(uname, "cpus") == 0)
        nr_cpus = 0;

    if (nr_cpus >= 0) {
        const char *device_type = of_get_flat_dt_prop(node,
                "device_type", NULL);

        if (device_type && strcmp(device_type, "cpu") == 0)
            nr_cpus++;
    }

    prev_depth = depth;

    return 0;
}

static void __init vexpress_dt_smp_init_cpus(void)
{
    int ncores = 0, i;

    switch (vexpress_dt_scu) {
    case GENERIC_SCU:
        ncores = of_scan_flat_dt(vexpress_dt_cpus_num, NULL);
        break;
    case CORTEX_A9_SCU:
        ncores = scu_get_core_count(vexpress_dt_cortex_a9_scu_base);
        break;
    default:
        WARN_ON(1);
        break;
    }

    if (ncores < 2)
        return;

    if (ncores > nr_cpu_ids) {
        pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
                ncores, nr_cpu_ids);
        ncores = nr_cpu_ids;
    }

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

    set_smp_cross_call(gic_raise_softirq);
}

static void __init vexpress_dt_smp_prepare_cpus(unsigned int max_cpus)
{
    int i;

    switch (vexpress_dt_scu) {
    case GENERIC_SCU:
        for (i = 0; i < max_cpus; i++)
            set_cpu_present(i, true);
        break;
    case CORTEX_A9_SCU:
        scu_enable(vexpress_dt_cortex_a9_scu_base);
        break;
    default:
        WARN_ON(1);
        break;
    }
}

#else

static void __init vexpress_dt_smp_init_cpus(void)
{
    WARN_ON(1);
}

void __init vexpress_dt_smp_prepare_cpus(unsigned int max_cpus)
{
    WARN_ON(1);
}

#endif

/*
 * Initialise the CPU possible map early - this describes the CPUs
 * which may be present or become present in the system.
 */
static void __init vexpress_smp_init_cpus(void)
{
    if (ct_desc)
        ct_desc->init_cpu_map();
    else
        vexpress_dt_smp_init_cpus();

}

static void __init vexpress_smp_prepare_cpus(unsigned int max_cpus)
{
    /*
     * Initialise the present map, which describes the set of CPUs
     * actually populated at the present time.
     */
    if (ct_desc)
        ct_desc->smp_enable(max_cpus);
    else
        vexpress_dt_smp_prepare_cpus(max_cpus);

    /*
     * Write the address of secondary startup into the
     * system-wide flags register. The boot monitor waits
     * until it receives a soft interrupt, and then the
     * secondary CPU branches to this address.
     */
    v2m_flags_set(virt_to_phys(versatile_secondary_startup));
}

struct smp_operations __initdata vexpress_smp_ops = {
    .smp_init_cpus      = vexpress_smp_init_cpus,
    .smp_prepare_cpus   = vexpress_smp_prepare_cpus,
    .smp_secondary_init = versatile_secondary_init,
    .smp_boot_secondary = versatile_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
    .cpu_die        = vexpress_cpu_die,
#endif
};