arch/arm64/kernel/cpu_ops.c

   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
  25 extern const struct cpu_operations smp_spin_table_ops;
  26 extern const struct cpu_operations cpu_psci_ops;
  27 #ifdef CONFIG_MTK_PSCI
  28 extern const struct cpu_operations mt_cpu_psci_ops;
  29 #endif
  30
  31 const struct cpu_operations *cpu_ops[NR_CPUS];
  32
  33 static const struct cpu_operations *supported_cpu_ops[] __initconst = {
  34 #ifdef CONFIG_SMP
  35         &smp_spin_table_ops,
  36         &cpu_psci_ops,
  37 #ifdef CONFIG_MTK_PSCI
  38         &mt_cpu_psci_ops,
  39 #endif
  40 #endif
  41         NULL,
  42 };
  43
  44 static const struct cpu_operations * __init cpu_get_ops(const char *name)
  45 {
  46         const struct cpu_operations **ops = supported_cpu_ops;
  47
  48         while (*ops) {
  49                 if (!strcmp(name, (*ops)->name))
  50                         return *ops;
  51
  52                 ops++;
  53         }
  54
  55         return NULL;
  56 }
  57
  58 /*
  59  * Read a cpu's enable method from the device tree and record it in cpu_ops.
  60  */
  61 int __init cpu_read_ops(struct device_node *dn, int cpu)
  62 {
  63         const char *enable_method = of_get_property(dn, "enable-method", NULL);
  64         if (!enable_method) {
  65                 /*
  66                  * The boot CPU may not have an enable method (e.g. when
  67                  * spin-table is used for secondaries). Don't warn spuriously.
  68                  */
  69                 if (cpu != 0)
  70                         pr_err("%s: missing enable-method property\n",
  71                                 dn->full_name);
  72                 return -ENOENT;
  73         }
  74
  75         cpu_ops[cpu] = cpu_get_ops(enable_method);
  76         if (!cpu_ops[cpu]) {
  77                 pr_err("%s: invalid enable-method property: %s\n",
  78                        dn->full_name, enable_method);
  79                 return -EOPNOTSUPP;
  80         }
  81
  82         return 0;
  83 }
  84
  85 void __init cpu_read_bootcpu_ops(void)
  86 {
  87         struct device_node *dn = NULL;
  88         u64 mpidr = cpu_logical_map(0);
  89
  90         while ((dn = of_find_node_by_type(dn, "cpu"))) {
  91                 u64 hwid;
  92                 const __be32 *prop;
  93
  94                 prop = of_get_property(dn, "reg", NULL);
  95                 if (!prop)
  96                         continue;
  97
  98                 hwid = of_read_number(prop, of_n_addr_cells(dn));
  99                 if (hwid == mpidr) {
 100                         cpu_read_ops(dn, 0);
 101                         of_node_put(dn);
 102                         return;
 103                 }
 104         }
 105 }