arch/powerpc/platforms/chrp/smp.c

   1 /*
   2  * Smp support for CHRP machines.
   3  *
   4  * Written by Cort Dougan (cort@cs.nmt.edu) borrowing a great
   5  * deal of code from the sparc and intel versions.
   6  *
   7  * Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
   8  *
   9  */
  10
  11 #include <linux/config.h>
  12 #include <linux/kernel.h>
  13 #include <linux/sched.h>
  14 #include <linux/smp.h>
  15 #include <linux/smp_lock.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/kernel_stat.h>
  18 #include <linux/delay.h>
  19 #include <linux/init.h>
  20 #include <linux/spinlock.h>
  21
  22 #include <asm/ptrace.h>
  23 #include <asm/atomic.h>
  24 #include <asm/irq.h>
  25 #include <asm/page.h>
  26 #include <asm/pgtable.h>
  27 #include <asm/sections.h>
  28 #include <asm/io.h>
  29 #include <asm/prom.h>
  30 #include <asm/smp.h>
  31 #include <asm/residual.h>
  32 #include <asm/time.h>
  33 #include <asm/open_pic.h>
  34 #include <asm/machdep.h>
  35 #include <asm/smp.h>
  36 #include <asm/mpic.h>
  37
  38 extern unsigned long smp_chrp_cpu_nr;
  39
  40 static int __init smp_chrp_probe(void)
  41 {
  42         struct device_node *cpus = NULL;
  43         unsigned int *reg;
  44         int reglen;
  45         int ncpus = 0;
  46         int cpuid;
  47         unsigned int phys;
  48
  49         /* Count CPUs in the device-tree */
  50         cpuid = 1;      /* the boot cpu is logical cpu 0 */
  51         while ((cpus = of_find_node_by_type(cpus, "cpu")) != NULL) {
  52                 phys = ncpus;
  53                 reg = (unsigned int *) get_property(cpus, "reg", &reglen);
  54                 if (reg && reglen >= sizeof(unsigned int))
  55                         /* hmmm, not having a reg property would be bad */
  56                         phys = *reg;
  57                 if (phys != boot_cpuid_phys) {
  58                         set_hard_smp_processor_id(cpuid, phys);
  59                         ++cpuid;
  60                 }
  61                 ++ncpus;
  62         }
  63
  64         printk(KERN_INFO "CHRP SMP probe found %d cpus\n", ncpus);
  65
  66         /* Nothing more to do if less than 2 of them */
  67         if (ncpus <= 1)
  68                 return 1;
  69
  70         mpic_request_ipis();
  71
  72         return ncpus;
  73 }
  74
  75 static void __devinit smp_chrp_kick_cpu(int nr)
  76 {
  77         *(unsigned long *)KERNELBASE = nr;
  78         asm volatile("dcbf 0,%0"::"r"(KERNELBASE):"memory");
  79 }
  80
  81 static void __devinit smp_chrp_setup_cpu(int cpu_nr)
  82 {
  83         mpic_setup_this_cpu();
  84 }
  85
  86 static DEFINE_SPINLOCK(timebase_lock);
  87 static unsigned int timebase_upper = 0, timebase_lower = 0;
  88
  89 void __devinit smp_chrp_give_timebase(void)
  90 {
  91         spin_lock(&timebase_lock);
  92         rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
  93         timebase_upper = get_tbu();
  94         timebase_lower = get_tbl();
  95         spin_unlock(&timebase_lock);
  96
  97         while (timebase_upper || timebase_lower)
  98                 barrier();
  99         rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
 100 }
 101
 102 void __devinit smp_chrp_take_timebase(void)
 103 {
 104         while (!(timebase_upper || timebase_lower))
 105                 barrier();
 106         spin_lock(&timebase_lock);
 107         set_tb(timebase_upper, timebase_lower);
 108         timebase_upper = 0;
 109         timebase_lower = 0;
 110         spin_unlock(&timebase_lock);
 111         printk("CPU %i taken timebase\n", smp_processor_id());
 112 }
 113
 114 /* CHRP with openpic */
 115 struct smp_ops_t chrp_smp_ops = {
 116         .message_pass = smp_mpic_message_pass,
 117         .probe = smp_chrp_probe,
 118         .kick_cpu = smp_chrp_kick_cpu,
 119         .setup_cpu = smp_chrp_setup_cpu,
 120         .give_timebase = smp_chrp_give_timebase,
 121         .take_timebase = smp_chrp_take_timebase,
 122 };