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 *boot_cpu_clk;
  39
  40 static struct clk *get_cpu_clk(int cpu)
  41 {
  42         struct clk *cpu_clk;
  43         struct device_node *np = of_get_cpu_node(cpu, NULL);
  44
  45         if (WARN(!np, "missing cpu node\n"))
  46                 return NULL;
  47         cpu_clk = of_clk_get(np, 0);
  48         if (WARN_ON(IS_ERR(cpu_clk)))
  49                 return NULL;
  50         return cpu_clk;
  51 }
  52
  53 static int armada_xp_boot_secondary(unsigned int cpu, struct task_struct *idle)
  54 {
  55         int ret, hw_cpu;
  56
  57         pr_info("Booting CPU %d\n", cpu);
  58
  59         hw_cpu = cpu_logical_map(cpu);
  60         mvebu_pmsu_set_cpu_boot_addr(hw_cpu, armada_xp_secondary_startup);
  61
  62         /*
  63          * This is needed to wake up CPUs in the offline state after
  64          * using CPU hotplug.
  65          */
  66         arch_send_wakeup_ipi_mask(cpumask_of(cpu));
  67
  68         /*
  69          * This is needed to take secondary CPUs out of reset on the
  70          * initial boot.
  71          */
  72         ret = mvebu_cpu_reset_deassert(hw_cpu);
  73         if (ret) {
  74                 pr_warn("unable to boot CPU: %d\n", ret);
  75                 return ret;
  76         }
  77
  78         return 0;
  79 }
  80
  81 /*
  82  * When a CPU is brought back online, either through CPU hotplug, or
  83  * because of the boot of a kexec'ed kernel, the PMSU configuration
  84  * for this CPU might be in the deep idle state, preventing this CPU
  85  * from receiving interrupts. Here, we therefore take out the current
  86  * CPU from this state, which was entered by armada_xp_cpu_die()
  87  * below.
  88  */
  89 static void armada_xp_secondary_init(unsigned int cpu)
  90 {
  91         mvebu_v7_pmsu_idle_exit();
  92 }
  93
  94 static void __init armada_xp_smp_init_cpus(void)
  95 {
  96         unsigned int ncores = num_possible_cpus();
  97
  98         if (ncores == 0 || ncores > ARMADA_XP_MAX_CPUS)
  99                 panic("Invalid number of CPUs in DT\n");
 100 }
 101
 102 static int armada_xp_sync_secondary_clk(unsigned int cpu)
 103 {
 104         struct clk *cpu_clk = get_cpu_clk(cpu);
 105
 106         if (!cpu_clk || !boot_cpu_clk)
 107                 return 0;
 108
 109         clk_prepare_enable(cpu_clk);
 110         clk_set_rate(cpu_clk, clk_get_rate(boot_cpu_clk));
 111
 112         return 0;
 113 }
 114
 115 static void __init armada_xp_smp_prepare_cpus(unsigned int max_cpus)
 116 {
 117         struct device_node *node;
 118         struct resource res;
 119         int err;
 120
 121         flush_cache_all();
 122         set_cpu_coherent();
 123
 124         boot_cpu_clk = get_cpu_clk(smp_processor_id());
 125         if (boot_cpu_clk) {
 126                 clk_prepare_enable(boot_cpu_clk);
 127                 cpuhp_setup_state_nocalls(CPUHP_AP_ARM_MVEBU_SYNC_CLOCKS,
 128                                           "arm/mvebu/sync_clocks:online",
 129                                           armada_xp_sync_secondary_clk, NULL);
 130         }
 131
 132         /*
 133          * In order to boot the secondary CPUs we need to ensure
 134          * the bootROM is mapped at the correct address.
 135          */
 136         node = of_find_compatible_node(NULL, NULL, "marvell,bootrom");
 137         if (!node)
 138                 panic("Cannot find 'marvell,bootrom' compatible node");
 139
 140         err = of_address_to_resource(node, 0, &res);
 141         of_node_put(node);
 142         if (err < 0)
 143                 panic("Cannot get 'bootrom' node address");
 144
 145         if (res.start != AXP_BOOTROM_BASE ||
 146             resource_size(&res) != AXP_BOOTROM_SIZE)
 147                 panic("The address for the BootROM is incorrect");
 148 }
 149
 150 #ifdef CONFIG_HOTPLUG_CPU
 151 static void armada_xp_cpu_die(unsigned int cpu)
 152 {
 153         /*
 154          * CPU hotplug is implemented by putting offline CPUs into the
 155          * deep idle sleep state.
 156          */
 157         armada_370_xp_pmsu_idle_enter(true);
 158 }
 159
 160 /*
 161  * We need a dummy function, so that platform_can_cpu_hotplug() knows
 162  * we support CPU hotplug. However, the function does not need to do
 163  * anything, because CPUs going offline can enter the deep idle state
 164  * by themselves, without any help from a still alive CPU.
 165  */
 166 static int armada_xp_cpu_kill(unsigned int cpu)
 167 {
 168         return 1;
 169 }
 170 #endif
 171
 172 const struct smp_operations armada_xp_smp_ops __initconst = {
 173         .smp_init_cpus          = armada_xp_smp_init_cpus,
 174         .smp_prepare_cpus       = armada_xp_smp_prepare_cpus,
 175         .smp_boot_secondary     = armada_xp_boot_secondary,
 176         .smp_secondary_init     = armada_xp_secondary_init,
 177 #ifdef CONFIG_HOTPLUG_CPU
 178         .cpu_die                = armada_xp_cpu_die,
 179         .cpu_kill               = armada_xp_cpu_kill,
 180 #endif
 181 };
 182
 183 CPU_METHOD_OF_DECLARE(armada_xp_smp, "marvell,armada-xp-smp",
 184                       &armada_xp_smp_ops);
 185
 186 #define MV98DX3236_CPU_RESUME_CTRL_REG 0x08
 187 #define MV98DX3236_CPU_RESUME_ADDR_REG 0x04
 188
 189 static const struct of_device_id of_mv98dx3236_resume_table[] = {
 190         {
 191                 .compatible = "marvell,98dx3336-resume-ctrl",
 192         },
 193         { /* end of list */ },
 194 };
 195
 196 static int mv98dx3236_resume_set_cpu_boot_addr(int hw_cpu, void *boot_addr)
 197 {
 198         struct device_node *np;
 199         void __iomem *base;
 200         WARN_ON(hw_cpu != 1);
 201
 202         np = of_find_matching_node(NULL, of_mv98dx3236_resume_table);
 203         if (!np)
 204                 return -ENODEV;
 205
 206         base = of_io_request_and_map(np, 0, of_node_full_name(np));
 207         of_node_put(np);
 208         if (IS_ERR(base))
 209                 return PTR_ERR(base);
 210
 211         writel(0, base + MV98DX3236_CPU_RESUME_CTRL_REG);
 212         writel(__pa_symbol(boot_addr), base + MV98DX3236_CPU_RESUME_ADDR_REG);
 213
 214         iounmap(base);
 215
 216         return 0;
 217 }
 218
 219 static int mv98dx3236_boot_secondary(unsigned int cpu, struct task_struct *idle)
 220 {
 221         int ret, hw_cpu;
 222
 223         hw_cpu = cpu_logical_map(cpu);
 224         mv98dx3236_resume_set_cpu_boot_addr(hw_cpu,
 225                                             armada_xp_secondary_startup);
 226
 227         /*
 228          * This is needed to wake up CPUs in the offline state after
 229          * using CPU hotplug.
 230          */
 231         arch_send_wakeup_ipi_mask(cpumask_of(cpu));
 232
 233         /*
 234          * This is needed to take secondary CPUs out of reset on the
 235          * initial boot.
 236          */
 237         ret = mvebu_cpu_reset_deassert(hw_cpu);
 238         if (ret) {
 239                 pr_warn("unable to boot CPU: %d\n", ret);
 240                 return ret;
 241         }
 242
 243         return 0;
 244 }
 245
 246 static const struct smp_operations mv98dx3236_smp_ops __initconst = {
 247         .smp_init_cpus          = armada_xp_smp_init_cpus,
 248         .smp_prepare_cpus       = armada_xp_smp_prepare_cpus,
 249         .smp_boot_secondary     = mv98dx3236_boot_secondary,
 250         .smp_secondary_init     = armada_xp_secondary_init,
 251 #ifdef CONFIG_HOTPLUG_CPU
 252         .cpu_die                = armada_xp_cpu_die,
 253         .cpu_kill               = armada_xp_cpu_kill,
 254 #endif
 255 };
 256
 257 CPU_METHOD_OF_DECLARE(mv98dx3236_smp, "marvell,98dx3236-smp",
 258                       &mv98dx3236_smp_ops);