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
doorbell_setup_this_cpu(void)22 void 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 
doorbell_cause_ipi(int cpu,unsigned long data)29 void 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 
doorbell_exception(struct pt_regs * regs)36 void 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 */
doorbell_exception(struct pt_regs * regs)50 void 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