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 #include <asm/cpu_ops.h>
  25
  26 static phys_addr_t cpu_release_addr[NR_CPUS];
  27
  28 static int smp_spin_table_cpu_init(struct device_node *dn, unsigned int cpu)
  29 {
  30         /*
  31          * Determine the address from which the CPU is polling.
  32          */
  33         if (of_property_read_u64(dn, "cpu-release-addr",
  34                                  &cpu_release_addr[cpu])) {
  35                 pr_err("CPU %d: missing or invalid cpu-release-addr property\n",
  36                        cpu);
  37
  38                 return -1;
  39         }
  40
  41         return 0;
  42 }
  43
  44 static int smp_spin_table_cpu_prepare(unsigned int cpu)
  45 {
  46         void **release_addr;
  47
  48         if (!cpu_release_addr[cpu])
  49                 return -ENODEV;
  50
  51         release_addr = __va(cpu_release_addr[cpu]);
  52         release_addr[0] = (void *)__pa(secondary_holding_pen);
  53         __flush_dcache_area(release_addr, sizeof(release_addr[0]));
  54
  55         /*
  56          * Send an event to wake up the secondary CPU.
  57          */
  58         sev();
  59
  60         return 0;
  61 }
  62
  63 const struct cpu_operations smp_spin_table_ops = {
  64         .name           = "spin-table",
  65         .cpu_init       = smp_spin_table_cpu_init,
  66         .cpu_prepare    = smp_spin_table_cpu_prepare,
  67 };