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
  38 static 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
  51 static 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
  71 out:
  72         put_cpu();
  73 }
  74
  75 static 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  */
 112 static void armada_xp_secondary_init(unsigned int cpu)
 113 {
 114         mvebu_v7_pmsu_idle_exit();
 115 }
 116
 117 static 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
 125 static 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         of_node_put(node);
 144         if (err < 0)
 145                 panic("Cannot get 'bootrom' node address");
 146
 147         if (res.start != AXP_BOOTROM_BASE ||
 148             resource_size(&res) != AXP_BOOTROM_SIZE)
 149                 panic("The address for the BootROM is incorrect");
 150 }
 151
 152 #ifdef CONFIG_HOTPLUG_CPU
 153 static void armada_xp_cpu_die(unsigned int cpu)
 154 {
 155         /*
 156          * CPU hotplug is implemented by putting offline CPUs into the
 157          * deep idle sleep state.
 158          */
 159         armada_370_xp_pmsu_idle_enter(true);
 160 }
 161
 162 /*
 163  * We need a dummy function, so that platform_can_cpu_hotplug() knows
 164  * we support CPU hotplug. However, the function does not need to do
 165  * anything, because CPUs going offline can enter the deep idle state
 166  * by themselves, without any help from a still alive CPU.
 167  */
 168 static int armada_xp_cpu_kill(unsigned int cpu)
 169 {
 170         return 1;
 171 }
 172 #endif
 173
 174 const struct smp_operations armada_xp_smp_ops __initconst = {
 175         .smp_init_cpus          = armada_xp_smp_init_cpus,
 176         .smp_prepare_cpus       = armada_xp_smp_prepare_cpus,
 177         .smp_boot_secondary     = armada_xp_boot_secondary,
 178         .smp_secondary_init     = armada_xp_secondary_init,
 179 #ifdef CONFIG_HOTPLUG_CPU
 180         .cpu_die                = armada_xp_cpu_die,
 181         .cpu_kill               = armada_xp_cpu_kill,
 182 #endif
 183 };
 184
 185 CPU_METHOD_OF_DECLARE(armada_xp_smp, "marvell,armada-xp-smp",
 186                       &armada_xp_smp_ops);