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/percpu.h>
17
18 #include <asm/dbell.h>
19 #include <asm/irq_regs.h>
20
21 #ifdef CONFIG_SMP
22 struct doorbell_cpu_info {
23 unsigned long messages; /* current messages bits */
24 unsigned int tag; /* tag value */
25 };
26
27 static DEFINE_PER_CPU(struct doorbell_cpu_info, doorbell_cpu_info);
28
doorbell_setup_this_cpu(void)29 void doorbell_setup_this_cpu(void)
30 {
31 struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
32
33 info->messages = 0;
34 info->tag = mfspr(SPRN_PIR) & 0x3fff;
35 }
36
doorbell_message_pass(int target,int msg)37 void doorbell_message_pass(int target, int msg)
38 {
39 struct doorbell_cpu_info *info;
40 int i;
41
42 if (target < NR_CPUS) {
43 info = &per_cpu(doorbell_cpu_info, target);
44 set_bit(msg, &info->messages);
45 ppc_msgsnd(PPC_DBELL, 0, info->tag);
46 }
47 else if (target == MSG_ALL_BUT_SELF) {
48 for_each_online_cpu(i) {
49 if (i == smp_processor_id())
50 continue;
51 info = &per_cpu(doorbell_cpu_info, i);
52 set_bit(msg, &info->messages);
53 ppc_msgsnd(PPC_DBELL, 0, info->tag);
54 }
55 }
56 else { /* target == MSG_ALL */
57 for_each_online_cpu(i) {
58 info = &per_cpu(doorbell_cpu_info, i);
59 set_bit(msg, &info->messages);
60 }
61 ppc_msgsnd(PPC_DBELL, PPC_DBELL_MSG_BRDCAST, 0);
62 }
63 }
64
doorbell_exception(struct pt_regs * regs)65 void doorbell_exception(struct pt_regs *regs)
66 {
67 struct pt_regs *old_regs = set_irq_regs(regs);
68 struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
69 int msg;
70
71 /* Warning: regs can be NULL when called from irq enable */
72
73 if (!info->messages || (num_online_cpus() < 2))
74 goto out;
75
76 for (msg = 0; msg < 4; msg++)
77 if (test_and_clear_bit(msg, &info->messages))
78 smp_message_recv(msg);
79
80 out:
81 set_irq_regs(old_regs);
82 }
83
doorbell_check_self(void)84 void doorbell_check_self(void)
85 {
86 struct doorbell_cpu_info *info = &__get_cpu_var(doorbell_cpu_info);
87
88 if (!info->messages)
89 return;
90
91 ppc_msgsnd(PPC_DBELL, 0, info->tag);
92 }
93
94 #else /* CONFIG_SMP */
doorbell_exception(struct pt_regs * regs)95 void doorbell_exception(struct pt_regs *regs)
96 {
97 printk(KERN_WARNING "Received doorbell on non-smp system\n");
98 }
99 #endif /* CONFIG_SMP */
100
101