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 #include <asm/kvm_ppc.h>
  21
  22 #ifdef CONFIG_SMP
  23 void doorbell_setup_this_cpu(void)
  24 {
  25         unsigned long tag = mfspr(SPRN_DOORBELL_CPUTAG) & PPC_DBELL_TAG_MASK;
  26
  27         smp_muxed_ipi_set_data(smp_processor_id(), tag);
  28 }
  29
  30 void doorbell_cause_ipi(int cpu, unsigned long data)
  31 {
  32         /* Order previous accesses vs. msgsnd, which is treated as a store */
  33         mb();
  34         ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, data);
  35 }
  36
  37 void doorbell_exception(struct pt_regs *regs)
  38 {
  39         struct pt_regs *old_regs = set_irq_regs(regs);
  40
  41         irq_enter();
  42
  43         may_hard_irq_enable();
  44
  45         kvmppc_set_host_ipi(smp_processor_id(), 0);
  46         __this_cpu_inc(irq_stat.doorbell_irqs);
  47
  48         smp_ipi_demux();
  49
  50         irq_exit();
  51         set_irq_regs(old_regs);
  52 }
  53 #else /* CONFIG_SMP */
  54 void doorbell_exception(struct pt_regs *regs)
  55 {
  56         printk(KERN_WARNING "Received doorbell on non-smp system\n");
  57 }
  58 #endif /* CONFIG_SMP */
  59