arch/powerpc/platforms/wsp/smp.c

   1 /*
   2  *  SMP Support for A2 platforms
   3  *
   4  *  Copyright 2007 Benjamin Herrenschmidt, IBM Corp.
   5  *
   6  *  This program is free software; you can redistribute it and/or
   7  *  modify it under the terms of the GNU General Public License
   8  *  as published by the Free Software Foundation; either version
   9  *  2 of the License, or (at your option) any later version.
  10  *
  11  */
  12
  13 #include <linux/cpumask.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/of.h>
  17 #include <linux/smp.h>
  18
  19 #include <asm/dbell.h>
  20 #include <asm/machdep.h>
  21 #include <asm/xics.h>
  22
  23 #include "ics.h"
  24 #include "wsp.h"
  25
  26 static void smp_a2_setup_cpu(int cpu)
  27 {
  28         doorbell_setup_this_cpu();
  29
  30         if (cpu != boot_cpuid)
  31                 xics_setup_cpu();
  32 }
  33
  34 int smp_a2_kick_cpu(int nr)
  35 {
  36         const char *enable_method;
  37         struct device_node *np;
  38         int thr_idx;
  39
  40         if (nr < 0 || nr >= NR_CPUS)
  41                 return -ENOENT;
  42
  43         np = of_get_cpu_node(nr, &thr_idx);
  44         if (!np)
  45                 return -ENODEV;
  46
  47         enable_method = of_get_property(np, "enable-method", NULL);
  48         pr_devel("CPU%d has enable-method: \"%s\"\n", nr, enable_method);
  49
  50         if (!enable_method) {
  51                 printk(KERN_ERR "CPU%d has no enable-method\n", nr);
  52                 return -ENOENT;
  53         } else if (strcmp(enable_method, "ibm,a2-scom") == 0) {
  54                 if (a2_scom_startup_cpu(nr, thr_idx, np))
  55                         return -1;
  56         } else {
  57                 printk(KERN_ERR "CPU%d: Don't understand enable-method \"%s\"\n",
  58                        nr, enable_method);
  59                 return -EINVAL;
  60         }
  61
  62         /*
  63          * The processor is currently spinning, waiting for the
  64          * cpu_start field to become non-zero After we set cpu_start,
  65          * the processor will continue on to secondary_start
  66          */
  67         paca[nr].cpu_start = 1;
  68
  69         return 0;
  70 }
  71
  72 static int __init smp_a2_probe(void)
  73 {
  74         return num_possible_cpus();
  75 }
  76
  77 static struct smp_ops_t a2_smp_ops = {
  78         .message_pass   = NULL, /* Use smp_muxed_ipi_message_pass */
  79         .cause_ipi      = doorbell_cause_ipi,
  80         .probe          = smp_a2_probe,
  81         .kick_cpu       = smp_a2_kick_cpu,
  82         .setup_cpu      = smp_a2_setup_cpu,
  83 };
  84
  85 void __init a2_setup_smp(void)
  86 {
  87         smp_ops = &a2_smp_ops;
  88 }