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

   1/*
   2 * Symmetric Multi Processing (SMP) support for Armada XP
   3 *
   4 * Copyright (C) 2012 Marvell
   5 *
   6 * Lior Amsalem <alior@marvell.com>
   7 * Yehuda Yitschak <yehuday@marvell.com>
   8 * Gregory CLEMENT <gregory.clement@free-electrons.com>
   9 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
  10 *
  11 * This file is licensed under the terms of the GNU General Public
  12 * License version 2.  This program is licensed "as is" without any
  13 * warranty of any kind, whether express or implied.
  14 *
  15 * The Armada XP SoC has 4 ARMv7 PJ4B CPUs running in full HW coherency
  16 * This file implements the routines for preparing the SMP infrastructure
  17 * and waking up the secondary CPUs
  18 */
  19
  20#include <linux/init.h>
  21#include <linux/smp.h>
  22#include <linux/clk.h>
  23#include <linux/of.h>
  24#include <linux/of_address.h>
  25#include <linux/mbus.h>
  26#include <asm/cacheflush.h>
  27#include <asm/smp_plat.h>
  28#include "common.h"
  29#include "armada-370-xp.h"
  30#include "pmsu.h"
  31#include "coherency.h"
  32
  33#define ARMADA_XP_MAX_CPUS 4
  34
  35#define AXP_BOOTROM_BASE 0xfff00000
  36#define AXP_BOOTROM_SIZE 0x100000
  37
  38static struct clk *get_cpu_clk(int cpu)
  39{
  40        struct clk *cpu_clk;
  41        struct device_node *np = of_get_cpu_node(cpu, NULL);
  42
  43        if (WARN(!np, "missing cpu node\n"))
  44                return NULL;
  45        cpu_clk = of_clk_get(np, 0);
  46        if (WARN_ON(IS_ERR(cpu_clk)))
  47                return NULL;
  48        return cpu_clk;
  49}
  50
  51static void set_secondary_cpu_clock(unsigned int cpu)
  52{
  53        int thiscpu;
  54        unsigned long rate;
  55        struct clk *cpu_clk;
  56
  57        thiscpu = get_cpu();
  58
  59        cpu_clk = get_cpu_clk(thiscpu);
  60        if (!cpu_clk)
  61                goto out;
  62        clk_prepare_enable(cpu_clk);
  63        rate = clk_get_rate(cpu_clk);
  64
  65        cpu_clk = get_cpu_clk(cpu);
  66        if (!cpu_clk)
  67                goto out;
  68        clk_set_rate(cpu_clk, rate);
  69        clk_prepare_enable(cpu_clk);
  70
  71out:
  72        put_cpu();
  73}
  74
  75static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle)
  76{
  77        int ret, hw_cpu;
  78
  79        pr_info("Booting CPU %d\n", cpu);
  80
  81        hw_cpu = cpu_logical_map(cpu);
  82        set_secondary_cpu_clock(hw_cpu);
  83        mvebu_pmsu_set_cpu_boot_addr(hw_cpu, armada_xp_secondary_startup);
  84
  85        /*
  86         * This is needed to wake up CPUs in the offline state after
  87         * using CPU hotplug.
  88         */
  89        arch_send_wakeup_ipi_mask(cpumask_of(cpu));
  90
  91        /*
  92         * This is needed to take secondary CPUs out of reset on the
  93         * initial boot.
  94         */
  95        ret = mvebu_cpu_reset_deassert(hw_cpu);
  96        if (ret) {
  97                pr_warn("unable to boot CPU: %d\n", ret);
  98                return ret;
  99        }
 100
 101        return 0;
 102}
 103
 104/*
 105 * When a CPU is brought back online, either through CPU hotplug, or
 106 * because of the boot of a kexec'ed kernel, the PMSU configuration
 107 * for this CPU might be in the deep idle state, preventing this CPU
 108 * from receiving interrupts. Here, we therefore take out the current
 109 * CPU from this state, which was entered by armada_xp_cpu_die()
 110 * below.
 111 */
 112static void armada_xp_secondary_init(unsigned int cpu)
 113{
 114        mvebu_v7_pmsu_idle_exit();
 115}
 116
 117static void __init armada_xp_smp_init_cpus(void)
 118{
 119        unsigned int ncores = num_possible_cpus();
 120
 121        if (ncores == 0 || ncores > ARMADA_XP_MAX_CPUS)
 122                panic("Invalid number of CPUs in DT\n");
 123}
 124
 125static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus)
 126{
 127        struct device_node *node;
 128        struct resource res;
 129        int err;
 130
 131        flush_cache_all();
 132        set_cpu_coherent();
 133
 134        /*
 135         * In order to boot the secondary CPUs we need to ensure
 136         * the bootROM is mapped at the correct address.
 137         */
 138        node = of_find_compatible_node(NULL, NULL, "marvell,bootrom");
 139        if (!node)
 140                panic("Cannot find 'marvell,bootrom' compatible node");
 141
 142        err = of_address_to_resource(node, 0, &res);
 143        if (err < 0)
 144                panic("Cannot get 'bootrom' node address");
 145
 146        if (res.start != AXP_BOOTROM_BASE ||
 147            resource_size(&res) != AXP_BOOTROM_SIZE)
 148                panic("The address for the BootROM is incorrect");
 149}
 150
 151#ifdef CONFIG_HOTPLUG_CPU
 152static void armada_xp_cpu_die(unsigned int cpu)
 153{
 154        /*
 155         * CPU hotplug is implemented by putting offline CPUs into the
 156         * deep idle sleep state.
 157         */
 158        armada_370_xp_pmsu_idle_enter(true);
 159}
 160
 161/*
 162 * We need a dummy function, so that platform_can_cpu_hotplug() knows
 163 * we support CPU hotplug. However, the function does not need to do
 164 * anything, because CPUs going offline can enter the deep idle state
 165 * by themselves, without any help from a still alive CPU.
 166 */
 167static int armada_xp_cpu_kill(unsigned int cpu)
 168{
 169        return 1;
 170}
 171#endif
 172
 173struct smp_operations armada_xp_smp_ops __initdata = {
 174        .smp_init_cpus          = armada_xp_smp_init_cpus,
 175        .smp_prepare_cpus       = armada_xp_smp_prepare_cpus,
 176        .smp_boot_secondary     = armada_xp_boot_secondary,
 177        .smp_secondary_init     = armada_xp_secondary_init,
 178#ifdef CONFIG_HOTPLUG_CPU
 179        .cpu_die                = armada_xp_cpu_die,
 180        .cpu_kill               = armada_xp_cpu_kill,
 181#endif
 182};
 183
 184CPU_METHOD_OF_DECLARE(armada_xp_smp, "marvell,armada-xp-smp",
 185                      &armada_xp_smp_ops);
 186