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/interrupt.h>
  22 #include <linux/kernel_stat.h>
  23 #include <linux/delay.h>
  24 #include <linux/init.h>
  25 #include <linux/spinlock.h>
  26 #include <linux/cache.h>
  27 #include <linux/err.h>
  28 #include <linux/sysdev.h>
  29 #include <linux/cpu.h>
  30
  31 #include <asm/ptrace.h>
  32 #include <asm/atomic.h>
  33 #include <asm/irq.h>
  34 #include <asm/page.h>
  35 #include <asm/pgtable.h>
  36 #include <asm/io.h>
  37 #include <asm/smp.h>
  38 #include <asm/paca.h>
  39 #include <asm/iseries/hv_call.h>
  40 #include <asm/time.h>
  41 #include <asm/machdep.h>
  42 #include <asm/cputable.h>
  43 #include <asm/system.h>
  44
  45 #include "smp.h"
  46
  47 static unsigned long iSeries_smp_message[NR_CPUS];
  48
  49 void iSeries_smp_message_recv(void)
  50 {
  51         int cpu = smp_processor_id();
  52         int msg;
  53
  54         if (num_online_cpus() < 2)
  55                 return;
  56
  57         for (msg = 0; msg < 4; msg++)
  58                 if (test_and_clear_bit(msg, &iSeries_smp_message[cpu]))
  59                         smp_message_recv(msg);
  60 }
  61
  62 static inline void smp_iSeries_do_message(int cpu, int msg)
  63 {
  64         set_bit(msg, &iSeries_smp_message[cpu]);
  65         HvCall_sendIPI(&(paca[cpu]));
  66 }
  67
  68 static void smp_iSeries_message_pass(int target, int msg)
  69 {
  70         int i;
  71
  72         if (target < NR_CPUS)
  73                 smp_iSeries_do_message(target, msg);
  74         else {
  75                 for_each_online_cpu(i) {
  76                         if ((target == MSG_ALL_BUT_SELF) &&
  77                                         (i == smp_processor_id()))
  78                                 continue;
  79                         smp_iSeries_do_message(i, msg);
  80                 }
  81         }
  82 }
  83
  84 static int smp_iSeries_probe(void)
  85 {
  86         return cpus_weight(cpu_possible_map);
  87 }
  88
  89 static void smp_iSeries_kick_cpu(int nr)
  90 {
  91         BUG_ON((nr < 0) || (nr >= NR_CPUS));
  92
  93         /* Verify that our partition has a processor nr */
  94         if (lppaca[nr].dyn_proc_status >= 2)
  95                 return;
  96
  97         /* The processor is currently spinning, waiting
  98          * for the cpu_start field to become non-zero
  99          * After we set cpu_start, the processor will
 100          * continue on to secondary_start in iSeries_head.S
 101          */
 102         paca[nr].cpu_start = 1;
 103 }
 104
 105 static void __devinit smp_iSeries_setup_cpu(int nr)
 106 {
 107 }
 108
 109 static struct smp_ops_t iSeries_smp_ops = {
 110         .message_pass = smp_iSeries_message_pass,
 111         .probe        = smp_iSeries_probe,
 112         .kick_cpu     = smp_iSeries_kick_cpu,
 113         .setup_cpu    = smp_iSeries_setup_cpu,
 114 };
 115
 116 /* This is called very early. */
 117 void __init smp_init_iSeries(void)
 118 {
 119         smp_ops = &iSeries_smp_ops;
 120 }