arch/powerpc/platforms/iseries/smp.c

   1 /*
   2  * SMP support for iSeries machines.
   3  *
   4  * Dave Engebretsen, Peter Bergner, and
   5  * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
   6  *
   7  * Plus various changes from other IBM teams...
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  */
  14
  15 #undef DEBUG
  16
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/sched.h>
  20 #include <linux/smp.h>
  21 #include <linux/smp_lock.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/kernel_stat.h>
  24 #include <linux/delay.h>
  25 #include <linux/init.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/cache.h>
  28 #include <linux/err.h>
  29 #include <linux/sysdev.h>
  30 #include <linux/cpu.h>
  31
  32 #include <asm/ptrace.h>
  33 #include <asm/atomic.h>
  34 #include <asm/irq.h>
  35 #include <asm/page.h>
  36 #include <asm/pgtable.h>
  37 #include <asm/io.h>
  38 #include <asm/smp.h>
  39 #include <asm/paca.h>
  40 #include <asm/iseries/hv_call.h>
  41 #include <asm/time.h>
  42 #include <asm/machdep.h>
  43 #include <asm/cputable.h>
  44 #include <asm/system.h>
  45
  46 #include "smp.h"
  47
  48 static unsigned long iSeries_smp_message[NR_CPUS];
  49
  50 void iSeries_smp_message_recv(void)
  51 {
  52         int cpu = smp_processor_id();
  53         int msg;
  54
  55         if (num_online_cpus() < 2)
  56                 return;
  57
  58         for (msg = 0; msg < 4; msg++)
  59                 if (test_and_clear_bit(msg, &iSeries_smp_message[cpu]))
  60                         smp_message_recv(msg);
  61 }
  62
  63 static inline void smp_iSeries_do_message(int cpu, int msg)
  64 {
  65         set_bit(msg, &iSeries_smp_message[cpu]);
  66         HvCall_sendIPI(&(paca[cpu]));
  67 }
  68
  69 static void smp_iSeries_message_pass(int target, int msg)
  70 {
  71         int i;
  72
  73         if (target < NR_CPUS)
  74                 smp_iSeries_do_message(target, msg);
  75         else {
  76                 for_each_online_cpu(i) {
  77                         if ((target == MSG_ALL_BUT_SELF) &&
  78                                         (i == smp_processor_id()))
  79                                 continue;
  80                         smp_iSeries_do_message(i, msg);
  81                 }
  82         }
  83 }
  84
  85 static int smp_iSeries_probe(void)
  86 {
  87         return cpus_weight(cpu_possible_map);
  88 }
  89
  90 static void smp_iSeries_kick_cpu(int nr)
  91 {
  92         BUG_ON((nr < 0) || (nr >= NR_CPUS));
  93
  94         /* Verify that our partition has a processor nr */
  95         if (lppaca[nr].dyn_proc_status >= 2)
  96                 return;
  97
  98         /* The processor is currently spinning, waiting
  99          * for the cpu_start field to become non-zero
 100          * After we set cpu_start, the processor will
 101          * continue on to secondary_start in iSeries_head.S
 102          */
 103         paca[nr].cpu_start = 1;
 104 }
 105
 106 static void __devinit smp_iSeries_setup_cpu(int nr)
 107 {
 108 }
 109
 110 static struct smp_ops_t iSeries_smp_ops = {
 111         .message_pass = smp_iSeries_message_pass,
 112         .probe        = smp_iSeries_probe,
 113         .kick_cpu     = smp_iSeries_kick_cpu,
 114         .setup_cpu    = smp_iSeries_setup_cpu,
 115 };
 116
 117 /* This is called very early. */
 118 void __init smp_init_iSeries(void)
 119 {
 120         smp_ops = &iSeries_smp_ops;
 121 }