LXR linux/arch/arm64/kernel/cpu

   1/*
   2 * CPU kernel entry/exit control
   3 *
   4 * Copyright (C) 2013 ARM Ltd.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19#include <asm/cpu_ops.h>
  20#include <asm/smp_plat.h>
  21#include <linux/errno.h>
  22#include <linux/of.h>
  23#include <linux/string.h>
  24
  25extern const struct cpu_operations smp_spin_table_ops;
  26extern const struct cpu_operations cpu_psci_ops;
  27
  28const struct cpu_operations *cpu_ops[NR_CPUS];
  29
  30static const struct cpu_operations *supported_cpu_ops[] __initconst = {
  31#ifdef CONFIG_SMP
  32        &smp_spin_table_ops,
  33#endif
  34        &cpu_psci_ops,
  35        NULL,
  36};
  37
  38static const struct cpu_operations * __init cpu_get_ops(const char *name)
  39{
  40        const struct cpu_operations **ops = supported_cpu_ops;
  41
  42        while (*ops) {
  43                if (!strcmp(name, (*ops)->name))
  44                        return *ops;
  45
  46                ops++;
  47        }
  48
  49        return NULL;
  50}
  51
  52/*
  53 * Read a cpu's enable method from the device tree and record it in cpu_ops.
  54 */
  55int __init cpu_read_ops(struct device_node *dn, int cpu)
  56{
  57        const char *enable_method = of_get_property(dn, "enable-method", NULL);
  58        if (!enable_method) {
  59                /*
  60                 * The boot CPU may not have an enable method (e.g. when
  61                 * spin-table is used for secondaries). Don't warn spuriously.
  62                 */
  63                if (cpu != 0)
  64                        pr_err("%s: missing enable-method property\n",
  65                                dn->full_name);
  66                return -ENOENT;
  67        }
  68
  69        cpu_ops[cpu] = cpu_get_ops(enable_method);
  70        if (!cpu_ops[cpu]) {
  71                pr_warn("%s: unsupported enable-method property: %s\n",
  72                        dn->full_name, enable_method);
  73                return -EOPNOTSUPP;
  74        }
  75
  76        return 0;
  77}
  78
  79void __init cpu_read_bootcpu_ops(void)
  80{
  81        struct device_node *dn = of_get_cpu_node(0, NULL);
  82        if (!dn) {
  83                pr_err("Failed to find device node for boot cpu\n");
  84                return;
  85        }
  86        cpu_read_ops(dn, 0);
  87}
  88