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/*
* Author: Kumar Gala <galak@kernel.crashing.org>
*
* Copyright 2009 Freescale Semiconductor Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/threads.h>
#include <linux/percpu.h>
#include <asm/dbell.h>
#include <asm/irq_regs.h>
#ifdef CONFIG_SMP
struct doorbell_cpu_info {
unsigned long messages; /* current messages bits */
unsigned int tag; /* tag value */
};
static DEFINE_PER_CPU(struct doorbell_cpu_info, doorbell_cpu_info);
void doorbell_setup_this_cpu(void)
{
struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
info->messages = 0;
info->tag = mfspr(SPRN_PIR) & 0x3fff;
}
void doorbell_message_pass(int target, int msg)
{
struct doorbell_cpu_info *info;
int i;
if (target < NR_CPUS) {
info = &per_cpu(doorbell_cpu_info, target);
set_bit(msg, &info->messages);
ppc_msgsnd(PPC_DBELL, 0, info->tag);
}
else if (target == MSG_ALL_BUT_SELF) {
for_each_online_cpu(i) {
if (i == smp_processor_id())
continue;
info = &per_cpu(doorbell_cpu_info, i);
set_bit(msg, &info->messages);
ppc_msgsnd(PPC_DBELL, 0, info->tag);
}
}
else { /* target == MSG_ALL */
for_each_online_cpu(i) {
info = &per_cpu(doorbell_cpu_info, i);
set_bit(msg, &info->messages);
}
ppc_msgsnd(PPC_DBELL, PPC_DBELL_MSG_BRDCAST, 0);
}
}
void doorbell_exception(struct pt_regs *regs)
{
struct pt_regs *old_regs = set_irq_regs(regs);
struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
int msg;
/* Warning: regs can be NULL when called from irq enable */
if (!info->messages || (num_online_cpus() < 2))
goto out;
for (msg = 0; msg < 4; msg++)
if (test_and_clear_bit(msg, &info->messages))
smp_message_recv(msg);
out:
set_irq_regs(old_regs);
}
void doorbell_check_self(void)
{
struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
if (!info->messages)
return;
ppc_msgsnd(PPC_DBELL, 0, info->tag);
}
#else /* CONFIG_SMP */
void doorbell_exception(struct pt_regs *regs)
{
printk(KERN_WARNING "Received doorbell on non-smp system\n");
}
#endif /* CONFIG_SMP */
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