arch/ppc/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
  35 extern unsigned long smp_chrp_cpu_nr;
  36
  37 static int __init
  38 smp_chrp_probe(void)
  39 {
  40         if (smp_chrp_cpu_nr > 1)
  41                 openpic_request_IPIs();
  42
  43         return smp_chrp_cpu_nr;
  44 }
  45
  46 static void __devinit
  47 smp_chrp_kick_cpu(int nr)
  48 {
  49         *(unsigned long *)KERNELBASE = nr;
  50         asm volatile("dcbf 0,%0"::"r"(KERNELBASE):"memory");
  51 }
  52
  53 static void __devinit
  54 smp_chrp_setup_cpu(int cpu_nr)
  55 {
  56         if (OpenPIC_Addr)
  57                 do_openpic_setup_cpu();
  58 }
  59
  60 static DEFINE_SPINLOCK(timebase_lock);
  61 static unsigned int timebase_upper = 0, timebase_lower = 0;
  62
  63 void __devinit
  64 smp_chrp_give_timebase(void)
  65 {
  66         spin_lock(&timebase_lock);
  67         call_rtas("freeze-time-base", 0, 1, NULL);
  68         timebase_upper = get_tbu();
  69         timebase_lower = get_tbl();
  70         spin_unlock(&timebase_lock);
  71
  72         while (timebase_upper || timebase_lower)
  73                 barrier();
  74         call_rtas("thaw-time-base", 0, 1, NULL);
  75 }
  76
  77 void __devinit
  78 smp_chrp_take_timebase(void)
  79 {
  80         while (!(timebase_upper || timebase_lower))
  81                 barrier();
  82         spin_lock(&timebase_lock);
  83         set_tb(timebase_upper, timebase_lower);
  84         timebase_upper = 0;
  85         timebase_lower = 0;
  86         spin_unlock(&timebase_lock);
  87         printk("CPU %i taken timebase\n", smp_processor_id());
  88 }
  89
  90 /* CHRP with openpic */
  91 struct smp_ops_t chrp_smp_ops __chrpdata = {
  92         .message_pass = smp_openpic_message_pass,
  93         .probe = smp_chrp_probe,
  94         .kick_cpu = smp_chrp_kick_cpu,
  95         .setup_cpu = smp_chrp_setup_cpu,
  96         .give_timebase = smp_chrp_give_timebase,
  97         .take_timebase = smp_chrp_take_timebase,
  98 };