arch/arm64/kernel/smp_spin_table.c

   1 /*
   2  * Spin Table SMP initialisation
   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 <linux/init.h>
  20 #include <linux/of.h>
  21 #include <linux/smp.h>
  22
  23 #include <asm/cacheflush.h>
  24
  25 static phys_addr_t cpu_release_addr[NR_CPUS];
  26
  27 static int __init smp_spin_table_init_cpu(struct device_node *dn, int cpu)
  28 {
  29         /*
  30          * Determine the address from which the CPU is polling.
  31          */
  32         if (of_property_read_u64(dn, "cpu-release-addr",
  33                                  &cpu_release_addr[cpu])) {
  34                 pr_err("CPU %d: missing or invalid cpu-release-addr property\n",
  35                        cpu);
  36
  37                 return -1;
  38         }
  39
  40         return 0;
  41 }
  42
  43 static int __init smp_spin_table_prepare_cpu(int cpu)
  44 {
  45         void **release_addr;
  46
  47         if (!cpu_release_addr[cpu])
  48                 return -ENODEV;
  49
  50         release_addr = __va(cpu_release_addr[cpu]);
  51         release_addr[0] = (void *)__pa(secondary_holding_pen);
  52         __flush_dcache_area(release_addr, sizeof(release_addr[0]));
  53
  54         /*
  55          * Send an event to wake up the secondary CPU.
  56          */
  57         sev();
  58
  59         return 0;
  60 }
  61
  62 const struct smp_enable_ops smp_spin_table_ops __initconst = {
  63         .name           = "spin-table",
  64         .init_cpu       = smp_spin_table_init_cpu,
  65         .prepare_cpu    = smp_spin_table_prepare_cpu,
  66 };