LXR linux/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#include <linux/hardirq.h>
  17
  18#include <asm/dbell.h>
  19#include <asm/irq_regs.h>
  20
  21#ifdef CONFIG_SMP
  22void doorbell_setup_this_cpu(void)
  23{
  24        unsigned long tag = mfspr(SPRN_PIR) & 0x3fff;
  25
  26        smp_muxed_ipi_set_data(smp_processor_id(), tag);
  27}
  28
  29void doorbell_cause_ipi(int cpu, unsigned long data)
  30{
  31        /* Order previous accesses vs. msgsnd, which is treated as a store */
  32        mb();
  33        ppc_msgsnd(PPC_DBELL, 0, data);
  34}
  35
  36void doorbell_exception(struct pt_regs *regs)
  37{
  38        struct pt_regs *old_regs = set_irq_regs(regs);
  39
  40        irq_enter();
  41
  42        may_hard_irq_enable();
  43
  44        smp_ipi_demux();
  45
  46        irq_exit();
  47        set_irq_regs(old_regs);
  48}
  49#else /* CONFIG_SMP */
  50void doorbell_exception(struct pt_regs *regs)
  51{
  52        printk(KERN_WARNING "Received doorbell on non-smp system\n");
  53}
  54#endif /* CONFIG_SMP */
  55
  56