arch/arm/mach-uniphier/platsmp.c

   1 /*
   2  * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/sizes.h>
  16 #include <linux/compiler.h>
  17 #include <linux/init.h>
  18 #include <linux/io.h>
  19 #include <linux/regmap.h>
  20 #include <linux/mfd/syscon.h>
  21 #include <asm/smp.h>
  22 #include <asm/smp_scu.h>
  23
  24 static struct regmap *sbcm_regmap;
  25
  26 static void __init uniphier_smp_prepare_cpus(unsigned int max_cpus)
  27 {
  28         static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 };
  29         unsigned long scu_base_phys = 0;
  30         void __iomem *scu_base;
  31
  32         sbcm_regmap = syscon_regmap_lookup_by_compatible(
  33                         "socionext,uniphier-system-bus-controller-misc");
  34         if (IS_ERR(sbcm_regmap)) {
  35                 pr_err("failed to regmap system-bus-controller-misc\n");
  36                 goto err;
  37         }
  38
  39         if (scu_a9_has_base())
  40                 scu_base_phys = scu_a9_get_base();
  41
  42         if (!scu_base_phys) {
  43                 pr_err("failed to get scu base\n");
  44                 goto err;
  45         }
  46
  47         scu_base = ioremap(scu_base_phys, SZ_128);
  48         if (!scu_base) {
  49                 pr_err("failed to remap scu base (0x%08lx)\n", scu_base_phys);
  50                 goto err;
  51         }
  52
  53         scu_enable(scu_base);
  54         iounmap(scu_base);
  55
  56         return;
  57 err:
  58         pr_warn("disabling SMP\n");
  59         init_cpu_present(&only_cpu_0);
  60         sbcm_regmap = NULL;
  61 }
  62
  63 static int uniphier_boot_secondary(unsigned int cpu,
  64                                    struct task_struct *idle)
  65 {
  66         int ret;
  67
  68         if (!sbcm_regmap)
  69                 return -ENODEV;
  70
  71         ret = regmap_write(sbcm_regmap, 0x1208,
  72                            virt_to_phys(secondary_startup));
  73         if (!ret)
  74                 asm("sev"); /* wake up secondary CPU */
  75
  76         return ret;
  77 }
  78
  79 struct smp_operations uniphier_smp_ops __initdata = {
  80         .smp_prepare_cpus       = uniphier_smp_prepare_cpus,
  81         .smp_boot_secondary     = uniphier_boot_secondary,
  82 };
  83 CPU_METHOD_OF_DECLARE(uniphier_smp, "socionext,uniphier-smp",
  84                       &uniphier_smp_ops);