LXR linux/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
  26static 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
  34int 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
  72static int __init smp_a2_probe(void)
  73{
  74        return num_possible_cpus();
  75}
  76
  77static 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
  85void __init a2_setup_smp(void)
  86{
  87        smp_ops = &a2_smp_ops;
  88}
  89