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/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/smp.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/kernel_stat.h>
  16 #include <linux/delay.h>
  17 #include <linux/init.h>
  18 #include <linux/spinlock.h>
  19
  20 #include <asm/ptrace.h>
  21 #include <asm/atomic.h>
  22 #include <asm/irq.h>
  23 #include <asm/page.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/sections.h>
  26 #include <asm/io.h>
  27 #include <asm/prom.h>
  28 #include <asm/smp.h>
  29 #include <asm/residual.h>
  30 #include <asm/time.h>
  31 #include <asm/machdep.h>
  32 #include <asm/mpic.h>
  33 #include <asm/rtas.h>
  34
  35 static void __devinit smp_chrp_kick_cpu(int nr)
  36 {
  37         *(unsigned long *)KERNELBASE = nr;
  38         asm volatile("dcbf 0,%0"::"r"(KERNELBASE):"memory");
  39 }
  40
  41 static void __devinit smp_chrp_setup_cpu(int cpu_nr)
  42 {
  43         mpic_setup_this_cpu();
  44 }
  45
  46 static DEFINE_SPINLOCK(timebase_lock);
  47 static unsigned int timebase_upper = 0, timebase_lower = 0;
  48
  49 void __devinit smp_chrp_give_timebase(void)
  50 {
  51         spin_lock(&timebase_lock);
  52         rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
  53         timebase_upper = get_tbu();
  54         timebase_lower = get_tbl();
  55         spin_unlock(&timebase_lock);
  56
  57         while (timebase_upper || timebase_lower)
  58                 barrier();
  59         rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
  60 }
  61
  62 void __devinit smp_chrp_take_timebase(void)
  63 {
  64         while (!(timebase_upper || timebase_lower))
  65                 barrier();
  66         spin_lock(&timebase_lock);
  67         set_tb(timebase_upper, timebase_lower);
  68         timebase_upper = 0;
  69         timebase_lower = 0;
  70         spin_unlock(&timebase_lock);
  71         printk("CPU %i taken timebase\n", smp_processor_id());
  72 }
  73
  74 /* CHRP with openpic */
  75 struct smp_ops_t chrp_smp_ops = {
  76         .message_pass = smp_mpic_message_pass,
  77         .probe = smp_mpic_probe,
  78         .kick_cpu = smp_chrp_kick_cpu,
  79         .setup_cpu = smp_chrp_setup_cpu,
  80         .give_timebase = smp_chrp_give_timebase,
  81         .take_timebase = smp_chrp_take_timebase,
  82 };