arch/powerpc/kernel/dbell.c

   1 /*
   2  * Author: Kumar Gala <galak@kernel.crashing.org>
   3  *
   4  * Copyright 2009 Freescale Semiconductor Inc.
   5  *
   6  * This program is free software; you can redistribute  it and/or modify it
   7  * under  the terms of  the GNU General  Public License as published by the
   8  * Free Software Foundation;  either version 2 of the  License, or (at your
   9  * option) any later version.
  10  */
  11
  12 #include <linux/stddef.h>
  13 #include <linux/kernel.h>
  14 #include <linux/smp.h>
  15 #include <linux/threads.h>
  16
  17 #include <asm/dbell.h>
  18
  19 #ifdef CONFIG_SMP
  20 unsigned long dbell_smp_message[NR_CPUS];
  21
  22 void smp_dbell_message_pass(int target, int msg)
  23 {
  24         int i;
  25
  26         if(target < NR_CPUS) {
  27                 set_bit(msg, &dbell_smp_message[target]);
  28                 ppc_msgsnd(PPC_DBELL, 0, target);
  29         }
  30         else if(target == MSG_ALL_BUT_SELF) {
  31                 for_each_online_cpu(i) {
  32                         if (i == smp_processor_id())
  33                                 continue;
  34                         set_bit(msg, &dbell_smp_message[i]);
  35                         ppc_msgsnd(PPC_DBELL, 0, i);
  36                 }
  37         }
  38         else { /* target == MSG_ALL */
  39                 for_each_online_cpu(i)
  40                         set_bit(msg, &dbell_smp_message[i]);
  41                 ppc_msgsnd(PPC_DBELL, PPC_DBELL_MSG_BRDCAST, 0);
  42         }
  43 }
  44
  45 void doorbell_exception(struct pt_regs *regs)
  46 {
  47         int cpu = smp_processor_id();
  48         int msg;
  49
  50         if (num_online_cpus() < 2)
  51                 return;
  52
  53         for (msg = 0; msg < 4; msg++)
  54                 if (test_and_clear_bit(msg, &dbell_smp_message[cpu]))
  55                         smp_message_recv(msg);
  56 }
  57
  58 #else /* CONFIG_SMP */
  59 void doorbell_exception(struct pt_regs *regs)
  60 {
  61         printk(KERN_WARNING "Received doorbell on non-smp system\n");
  62 }
  63 #endif /* CONFIG_SMP */
  64