LXR linux/arch/arm/mach-mvebu/platsmp-a9.c

   1/*
   2 * Symmetric Multi Processing (SMP) support for Marvell EBU Cortex-A9
   3 * based SOCs (Armada 375/38x).
   4 *
   5 * Copyright (C) 2014 Marvell
   6 *
   7 * Gregory CLEMENT <gregory.clement@free-electrons.com>
   8 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   9 *
  10 * This file is licensed under the terms of the GNU General Public
  11 * License version 2.  This program is licensed "as is" without any
  12 * warranty of any kind, whether express or implied.
  13 */
  14
  15#include <linux/init.h>
  16#include <linux/io.h>
  17#include <linux/of.h>
  18#include <linux/smp.h>
  19#include <linux/mbus.h>
  20#include <asm/smp_scu.h>
  21#include <asm/smp_plat.h>
  22#include "common.h"
  23#include "pmsu.h"
  24
  25extern void mvebu_cortex_a9_secondary_startup(void);
  26
  27static int mvebu_cortex_a9_boot_secondary(unsigned int cpu,
  28                                                    struct task_struct *idle)
  29{
  30        int ret, hw_cpu;
  31
  32        pr_info("Booting CPU %d\n", cpu);
  33
  34        /*
  35         * Write the address of secondary startup into the system-wide
  36         * flags register. The boot monitor waits until it receives a
  37         * soft interrupt, and then the secondary CPU branches to this
  38         * address.
  39         */
  40        hw_cpu = cpu_logical_map(cpu);
  41        if (of_machine_is_compatible("marvell,armada375"))
  42                mvebu_system_controller_set_cpu_boot_addr(mvebu_cortex_a9_secondary_startup);
  43        else
  44                mvebu_pmsu_set_cpu_boot_addr(hw_cpu, mvebu_cortex_a9_secondary_startup);
  45        smp_wmb();
  46
  47        /*
  48         * Doing this before deasserting the CPUs is needed to wake up CPUs
  49         * in the offline state after using CPU hotplug.
  50         */
  51        arch_send_wakeup_ipi_mask(cpumask_of(cpu));
  52
  53        ret = mvebu_cpu_reset_deassert(hw_cpu);
  54        if (ret) {
  55                pr_err("Could not start the secondary CPU: %d\n", ret);
  56                return ret;
  57        }
  58
  59        return 0;
  60}
  61/*
  62 * When a CPU is brought back online, either through CPU hotplug, or
  63 * because of the boot of a kexec'ed kernel, the PMSU configuration
  64 * for this CPU might be in the deep idle state, preventing this CPU
  65 * from receiving interrupts. Here, we therefore take out the current
  66 * CPU from this state, which was entered by armada_38x_cpu_die()
  67 * below.
  68 */
  69static void armada_38x_secondary_init(unsigned int cpu)
  70{
  71        mvebu_v7_pmsu_idle_exit();
  72}
  73
  74#ifdef CONFIG_HOTPLUG_CPU
  75static void armada_38x_cpu_die(unsigned int cpu)
  76{
  77        /*
  78         * CPU hotplug is implemented by putting offline CPUs into the
  79         * deep idle sleep state.
  80         */
  81        armada_38x_do_cpu_suspend(true);
  82}
  83
  84/*
  85 * We need a dummy function, so that platform_can_cpu_hotplug() knows
  86 * we support CPU hotplug. However, the function does not need to do
  87 * anything, because CPUs going offline can enter the deep idle state
  88 * by themselves, without any help from a still alive CPU.
  89 */
  90static int armada_38x_cpu_kill(unsigned int cpu)
  91{
  92        return 1;
  93}
  94#endif
  95
  96static const struct smp_operations mvebu_cortex_a9_smp_ops __initconst = {
  97        .smp_boot_secondary     = mvebu_cortex_a9_boot_secondary,
  98};
  99
 100static const struct smp_operations armada_38x_smp_ops __initconst = {
 101        .smp_boot_secondary     = mvebu_cortex_a9_boot_secondary,
 102        .smp_secondary_init     = armada_38x_secondary_init,
 103#ifdef CONFIG_HOTPLUG_CPU
 104        .cpu_die                = armada_38x_cpu_die,
 105        .cpu_kill               = armada_38x_cpu_kill,
 106#endif
 107};
 108
 109CPU_METHOD_OF_DECLARE(mvebu_armada_375_smp, "marvell,armada-375-smp",
 110                      &mvebu_cortex_a9_smp_ops);
 111CPU_METHOD_OF_DECLARE(mvebu_armada_380_smp, "marvell,armada-380-smp",
 112                      &armada_38x_smp_ops);
 113CPU_METHOD_OF_DECLARE(mvebu_armada_390_smp, "marvell,armada-390-smp",
 114                      &armada_38x_smp_ops);
 115